NMERI 99/8/33350 

TROPODEGRADABLE BROMOCARBON EXTINGUISHANTS 

Joseph Lifke, April Martinez, and Robert E. Tapscott, J. Douglas Mather 

Center for Global Environmental Technologies 

NEW MEXICO ENGINEERING RESEARCH INSTITUTE 

The University of New Mexico 

901 University Boulevard SE 

Albuquerque, New Mexico 87106-4339 

Final Report, 3/98 – 9/99 

May, 2001 

Sponsored by: 

The Department of Defense 

Strategic Environmental Research and Development Program

The views and conclusions contained in this document are those of the authors and should not be 

interpreted as representing the official policies, either expressed or implied, of the Strategic 

Environmental Research and Development Program or any other part of the U.S. Government. 
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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 

 5/2001

3. REPORT TYPE AND DATES COVERED 

Final Report, 3/98 – 9/99

4. TITLE AND SUBTITLE 

 TROPOEGRADABLE BROMOCARBON 

EXTNGUISHANTS 

5. FUNDING NUMBERS 

 

DASW01-00-P3345 

6. AUTHOR(S) 

J. Douglas Mather, Robert E. Tapscott, Joseph Lifke, 

April Martinez 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 

New Mexico Engineering Research Institute 

The University of New Mexico 

Albuquerque, New Mexico 87106-4339

8. PERFORMING ORGANIZATION 

REPORT NUMBER 

 NMERI 99/8/33350

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 

Department of Defense – Strategic Environmental Research and 

Development Program

10. SPONSORING/MONITORING 

AGENCY REPORT NUMBER 

11 SUPPLEMENTARY NOTES 

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE 

13. ABSTRACT (Maximum 200 words)

Current commercially available Halon 1301 replacement compounds (other than CF3I) lack the fire suppression 

effectiveness of halon primarily because they do not contain bromine in their molecular structure. Bromine is thought to catalyze 

radical recombination reactions which deprive the combustion process of the •OH and •H radical species which promote the 

combustion of fuel molecules in the gas phase. This project was conceived to develop new fire suppressants incorporating bromine 

by basing the compounds on chemical families with expected or demonstrated short atmospheric lifetimes. These compounds are 

said to be tropodegradable bromocarbons. The targeted chemical families in order of importance were partially fluorinated alkenes, 

ethers, and amines. The alkenes have now been shown to have very short lifetimes on the order of days. This project identified 

several low boiling brominated and partially fluorinated alkenes, ethers, and amines with potential of meeting the toxicity, fire 

suppression, and environmental criteria currently identified under the EPA’s SNAP program for halon replacements. Several of 

these tropodegradable compounds were subsequently acquired and their cup-burner flame suppression performance evaluated with

promising results. Several of the bromofluoro alkenes have now also been evaluated in an acute inhalation toxicity test which

yielded extremely promising results for this chemical family. This is an interim report covering the first phase of an ongoing effort. 

14. SUBJECT TERMS 

 Bromofluoro-alkene; Bromofluoro-ether, Bromofluoro-amine, Halon 1301,

15. NUMBER OF PAGES 

Fire Extinguishant, tropodegradable, cup-burner, atmospheric lifetime 16. PRICE CODE 

17. SECURITY

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ii
PREFACE 

This report was prepared by the Center for Global Environmental Technologies (CGET) 

at the New Mexico Engineering Research Institute (NMERI), The University of New Mexico, 

Albuquerque, New Mexico, for the Department of Defense Strategic Environmental Research 

and Development Program Next Generation Fire Suppression Program under Contract 

DASW01-00-P3345. The corresponding University of New Mexico Contract Number is 8-

33350. 

The Start Date was March 1, 1998, and the End Date was September 30, 1999. The NGP 

Contracting Officer’s Technical Representative is Dr. Ronald Sheinson and the NMERI 

Principal Investigator is Dr. J. Douglas Mather and the Co-Principal Investigator is Dr. Robert E. 

Tapscott. 

NMERI 99/8/33350 

(The reverse of this page is intentionally left blank.) 

iii
EXECUTIVE SUMMARY 

The objective of the Tropodegradable Bromocarbon Extinguishants project is to identify 

new chemical compounds with the potential to replace Halon 1301 in total flood fire 

extinguishment and explosion inertion applications. 

Development of replacement chemicals for existing halons is mandated by international 

treaty, based on the now widely accepted link between atmospheric bromine levels and 

stratospheric ozone depletion. 

Under the Montreal Protocol, an international treaty enacted in 1987 and amended in 

1990, 1992, and 1995, the production of halon fire and explosion protection agents was phased 

out in the United States and other industrialized nations at the end of 1993. One of these agents, 

Halon 1301, is used throughout the US DoD in total flood applications. To date, no 

environmentally acceptable substitute equivalent to Halon 1301 in toxicity, effectiveness, and 

dimensionality has been identified. Most of the replacements now being commercialized or 

proposed for commercialization are saturated fluorine-containing halocarbons: 

hydrofluorocarbons (HFC), hydrochlorofluorocarbons (HCFC), and perfluorocarbons (PFC or 

FC) and fluoroiodocarbons (FIC). Except for CF3I these replacement chemicals are less 

effective than Halon 1301 in most scenarios and/or and have one or more adverse global 

environmental impacts (ozone depletion, global warming, long atmospheric lifetime). It is 

unlikely that new, exceptionally effective, and environmentally acceptable halon replacements 

will be identified among the normal saturated fluorine-containing halocarbons. Earlier DoD 

funded projects determined that brominated halocarbons with chemical features leading to very 

short atmospheric lifetimes (“tropodegradable” bromocarbons) are very promising compounds 

for evaluation as halon replacements. This projects goal was to identify, acquire and 

characterize the flame extinguishment performance of tropodegradable bromocarbons with the 

potential of meeting all toxicity, environmental, and performance requirements of a Halon 1301 

replacement. 

The history of halon replacement development reflects concurrent progress in fire science 

and basic environmental and atmospheric research areas. Halon development history has the 

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iv
appearance of a sequential process involving research-based agent discovery, environmental 

research resulting in tighter acceptance and selection criteria followed by rejection of developed 

alternatives, and a resumption of applied research focused on fire suppression agents. At this 

point environmental property requirements and to a lesser extent toxicological performance 

targets for halon replacements have become more clearly refined and reliably serve as guides in 

compound selection and evaluation. 

The targeted compounds in this project all contain bromine and are fluorinated to render 

them non-flammable. Their expected short atmospheric lifetimes translate directly into very low 

ozone depletion and global warming potentials. The chemical families of interest include the 

bromofluoro alkenes, ethers, and amines. 

In this project, bromofluoroalkenes were the primary focus of compound selection, 

acquisition and testing efforts due to their promising toxicity, flame suppression, short 

atmospheric lifetime, and acceptable physical properties. The bromofluoro-alkene chemical 

family is probably the most studies of all candidate families. Should the remaining chemical 

families advance to the same level of study they may also prove to be just or more promising as 

sources of halon replacements. 

Data from the RTECS database as well as acute inhalation toxicity and subsequent 

AMES test data for several of the bromofluoro alkenes of interest here is very promising. Flame 

extinguishment testing of several bromofluoro alkenes have yielded cup-burner values 

comparable to those of halon 1301 and 1211. Finally, synthetic methods, in some cases, are 

expected to enable relatively low cost manufacture of selected bromofluoroalkenes and give 

hope to the potential for low cost industrial preparation of others. 

This project continued previous efforts to identify tropodegradable bromofluoro organic 

compounds with optimal boiling point and flame extinguishment properties. Through 

collaboration with the Advanced Agent Working Group (AAWG) and a U.S. Air Force Halon 

1211 replacement project eight bromofluoro-alkenes were evaluated for acute inhalation toxicity 

resulting in the identification of five promising compounds. 

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v
TABLE OF CONTENTS 

Section Page

SECTION I. PROJECT SUMMARY..............................................................................................1 

A. BACKGROUND ..................................................................................................1 

B. PROJECT TASKS................................................................................................5 

Task 1. Compound selection................................................................................5 

Task 2. Acquisition - Synthesis and Characterization ..........................................6 

Task 3. Cup-Burner Testing..................................................................................6 

C. TECHNICAL PROBLEMS..................................................................................7 

D. GENERAL METHODOLOGY............................................................................7 

E. TECHNICAL RESULTS......................................................................................8 

F. IMPORTANT FINDINGS..................................................................................10 

G. SIGNIFICANT HARDWARE DEVELOPMENT.............................................10 

H. SPECIAL COMMENTS.....................................................................................11 

I. IMPLICATIONS FOR FURTHER RESEARCH...............................................11 

SECTION II. BIBLIOGRAPHY ...................................................................................................13 

A. PAPERS PRESENTED ......................................................................................13 

SECTION III PROJECT DESCRIPTION.....................................................................................14 

A. COMPOUND SELECTION...............................................................................14 

1. Alkene toxicity information reviewed .......................................................16 

2. Amine Toxicity Information Reviewed.....................................................21 

3. Ether Toxicity Information Reviewed .......................................................21 

4. Atmospheric lifetime estimates for alkenes...............................................24 

5. Atmospheric lifetime estimates for ethers.................................................27 

6. Atmospheric lifetime estimates for amines................................................30 

7. Physical property estimates – boiling point effects...................................31 

B. COMPOUND SYNTHESIS AND ACQUISITION...........................................33 

vi
1. Bromofluoro-alkenes .................................................................................34 

2. Bromofluoro-ethers....................................................................................35 

3. Bromofluoro-amines..................................................................................36 

C. SYNTHESES PERFORMED OR ATTEMPTED..............................................37 

1. 2-Bromo-3,3,3-trifluoropropene, CH2=CBrCF3 ........................................37 

2. 1-Bromo-2-trifluoromethyl propene, ((CF3)2C=CHBr) ...........................38 

3. Fluorobromoalkyl-amines..........................................................................38 

D. COMMERCIAL AND ACADEMIC SOURCES...............................................38 

1. Compounds acquired .................................................................................39 

E. CUP-BURNER TESTING..................................................................................41 

SECTION IV. TECHNICAL PROBLEMS...................................................................................45 

SECTION V. RECOMMENDATIONS ........................................................................................46 

SECTION VI. CONCLUSION......................................................................................................47 

REFERENCES ..............................................................................................................................48 

APPENDIX A Glossary.................................................................................................................52 

vii
LIST OF FIGURES 

Figure Page

NMERI cup-burner utilizing mass loss flow rate characterization ............................................42 

NMERI cup-burner with premixed agent/air source. .................................................................43 

viii
LIST OF TABLES 

Table Page

Tropdegradable Compound Cup-Burner Values..........................................................................2 

Tropospheric Removal Mechanisms ............................................................................................4 

Targeted Halon 1301 Replacement Criteria .................................................................................6 

Tropodegradable Brominated Halocarbon Cup-burner Values....................................................9 

Tropodegradable Bromofluoro-Amines .....................................................................................10 

Acute Inhalation Data for Tropodegradable Alkenes.................................................................12 

List of 26 Halon 1301 Replacement Candidates ........................................................................15 

General Toxicity and Cardiac Sensitization Rules.....................................................................16 

ALC Values for Halogenated Amines........................................................................................17 

Selected Inhalation LC50 Toxicity Information. .........................................................................18 

Selected RTECS Alkene LCLO Inhalation Toxicity Information. ..............................................19 

Acute Inhalation Toxicity of HFAs. ...........................................................................................21

Toxicity of Ethers.......................................................................................................................22 

Toxicity of HFEs. .......................................................................................................................23 

HFE Toxicity evaluation.............................................................................................................23 

Atmospheric Lifetimes and ODP Values for Common HCFCs and CFCs. ...............................24 

Estimated hydrogen atom abstraction rate constants and alkene atmospheric lifetimes............26 

Partial List of Tropodegradable Alkenes....................................................................................27 

Tropodegradable Ethers..............................................................................................................29 

Three Carbon Tropodegradable Amines– NR1R2R3...................................................................31 

Four Carbon Tropodegradable Amines– NR1R2R3 ..................................................................31 

Estimated Maximum Boiling Point That Can Achieve a Given Concentration.........................33 

Amines Prepared by Bromobis-(trifluoromethyl)amine Addition to Alkenes. ..........................37 

Brominated Tropodegradable Alkenes Acquired .......................................................................39 

Tropodegradable Bromofluoro-amines Acquired.......................................................................40 

Compound Suppliers...................................................................................................................40 

Cup-burner Flame Extinguishment and Application Temperature Limits.................................44 

NMERI Cup-Burner Flame Extinguishment and Application Temperature Limits ..................44 

ix
x
LIST OF ABBREVIATIONS 

AAWG Advanced Agent Working Group 

ALC Approximate Lethal Concentration 

AD50 Dose that is anesthetic to 50 percent of an animal test population 

CAS Chemical Abstracts Service (American Chemical Society) 

CCOD CGET Chemical Options Database 

CGET Center for Global Environmental Technologies 

CSNOAEL cardiac sensitization - no observable adverse effect level 

DoD Department of Defense 

DTIC Defense Technical Information Center 

EPA U.S. Environmental Protection Agency 

FC (per)fluorocarbon 

FEC flame extinguishment concentration 

FIC fluoroiodocarbon 

GWP Global Warming Potential 

HCFC hydrochlorofluorocarbon 

HCFPE hydrochorofluoropolyether 

HFC hydrofluorocarbon 

HFE hydrofluoroether 

HFPE hydrofluoropolyether 

IR infrared 

IUPAC International Union of Pure and Applied Chemistry 

LCLO lowest concentration causing death 

LC50 concentration required to cause death in 50 percent of an animal test population 

LD50 dose required to cause death in 50 percent of an animal test population 

LOAEL Lowest Observable Adverse Effect Level 

MEDLARS Medical Literature Analysis and Retrieval System

MSDS Material Safety Data Sheet 

NIOSH National Institute for Occupational Safety and Health 

NGP Next Generation Program

xi
LIST OF ABBREVIATIONS (concluded) 

NOAEL No Observed Adverse Effect Level 

ODP Ozone Depletion Potential 

PFC perfluorocarbon 

QSAR Quantitative Structure-Activity Relationship 

QSPR Quantitative Structure-Property Relationship 

RTECS Registry of Toxic Effects of Chemical Substances 

SERDP Strategic Environmental Research and Development Program

SNAP Significant New Alternatives Policy 

TSCA Toxic Substance Control Act 

USAF United States Air Force 

UV ultraviolet 

WPAFB Wright-Patterson Air Force Base 

xii
LIST OF UNITS AND SYMBOLS 

A constant in vapor pressure equation 

B coefficient in vapor pressure equation 

g gram

H hour 

K Kelvin 

lb pound 

M minute 

mL milliliter 

p pressure 

ppm parts per million 

s second 

T temperature 

vol.% percent by volume 

wt.% percent by weight 

• denotes a free radical, e.g., •OH, the hydroxyl free radical 

xiii
SECTION I. PROJECT SUMMARY 

A. BACKGROUND 

Under the Montreal Protocol the production of the fire and explosion protection agents 

Halon 1301, Halon 1211, and Halon 2402 was phased out in the U.S. at the end of 1993.* To 

date, no environmentally acceptable halon substitute comparable to the existing halons in 

toxicity, effectiveness, and dimensionality has been identified. 

Halocarbons as replacements for halons have been well studied, and exceptionally 

effective, halon replacements have not been identified among the normal saturated halocarbons 

(excluding iodides and other halocarbons with chemical features leading to short atmospheric 

lifetimes).† The hydrochlorofluorocarbons (HCFC), perfluorocarbons (PFC or FC), and 

hydrofluorocarbons (HFC) are all less effective than the present halons in most scenarios. 

Moreover, all of these have some adverse global environmental impact (ozone depletion, global 

warming, and/or long atmospheric lifetime). PFCs and HCFCs are already subject to some

restrictions, and such restrictions may eventually extend to HFCs. 

There is, therefore, reason to look at compounds other than the normal saturated 

halocarbons. Nonhalocarbon candidates and halocarbons with chemical features leading to very 

short atmospheric lifetimes (“tropodegradable” halocarbons) are known as “advanced agents” 

have been assessed in detail [1, 2]. These compounds represent an opportunity to retain bromine 

in the chemical structure of the fire suppressant without risking significant impact on 

stratospheric ozone levels. 

Prior to this project very few tropodegradable bromocarbons had been acquired and 

evaluated for cup-burner performance. Those compounds for which data existed, Table 1, 

provided limited evidence of the potential of this group of chemicals to be halon replacements. 

 

*Only Halon 1211 and Halon 1301 have had significant use in the U.S. The primary use of 

Halon 2402 has been in the former Soviet Union and in a few eastern European countries. 

†Appendix A contains a glossary of chemical, toxicological, and other terms. 

1
Table 1. Tropdegradable Compound Cup-Burner Values 

Compound name Compound formula a

Cup-Burner, 

% 

1-bromo-3,3,3-trifluoropropene CHBr=CHCF3 4.5 

3-bromo-3,3-difluoropropene CH2=CHCBrF2

b

4.5 

2-bromo-3,3,3-trifluoropropene CH2=CBrCF3 2.6 

4-bromo-3,3,4,4-tetrafluorobutene CH2=CHCF2CBrF2 3.5 

4-bromo-3-chloro-3,4,4-trifluorobutene CH2=CHCClFCBrF2 4.5 

1-bromo-2,3,5,6-tetrafluoro-4-(trifluoromethyl)benzene C6BrF4CF3 4.3 

3-bromo-1,1,1-trifluoro-2-propanol CF3CHOHCH2Br 4.1 

3,3-dibromo-1,1,1-trifluoro-2-propanol CF3CHOHCHBr2 4.9 

a

n-heptane fuel using the NMERI Cup-Burner and mixing of separate air/agent flows. 

b

A value of 8.5% was reported earlier based on insufficient compound. 

Short atmospheric lifetimes of tropodegradable result from one or more of the following: 

(1) reaction with atmospheric hydroxyl free radicals; (2) photolysis; (3) reaction with 

tropospheric ozone; and (4) physical removal (rain-out) [2]. A number of tropodegradable or 

potentially tropodegradable halocarbons (e.g., alkenes, aromatics, polar-substituted halocarbons) 

have been identified as promising candidates for both Halon 1301 and Halon 1301 replacement. 

For the compounds of interest here, the atmospheric hydroxyl free radicals (•OH) 

abstract a hydrogen atom and/or add to an unsaturated molecule to give polar products. It has 

been found that the activation energy for hydrogen atom abstraction decreases (as expected) with 

decreasing dissociation energy of the C-H bond. Replacement of either a fluorine atom or a 

hydrogen atom by an oxygen or nitrogen atom alpha to a CH group decreases the bond 

dissociation energy and increases the reaction rate. Beta substitution generally has a much lower 

substituent effect on bond dissociation energies. We have calculated (in agreement with some

experimental data) that rate constants for reaction with hydroxyl free radicals increase by a factor 

of approximately 200 for addition of an ether linkage adjacent to a hydrogen atom. This gives 

atmospheric lifetimes as short as 0.3 years for some hydrofluoroethers (HFEs). Replacement of 

a fluorine with a bromine will reduce the atmospheric lifetime by about a factor of 10. Thus 

brominated HFEs should have atmospheric lifetimes as short as 11 days. Experimental 

2
characterization of OH radical addition to alkene double bonds indicate the trans-2-butene 

derivatives are likely to have the highest rates of OH addition to the double bond. 

Unfortunately, no reliable data exist for amines containing fluorine substitution. The 

atmospheric environmental parameters of some HFAs have been reported [3]. The reported 

lifetime for (CF3)2NCH3 of 0.28 years is of particular interest since replacement of one of the 

fluorine atoms by bromine is likely to reduce this to about 0.028 years due to enhanced 

photolysis[4]. A very small amount of data indicates that for bromine-containing compounds, 

each 10 years increase in atmospheric lifetime increases the ODP by approximately 2. Thus, for 

an atmospheric lifetime of 0.028, (CBrF2)(CF3)NCH3 would have an ODP of 0.006. 

Addition of •OH free radicals to unsaturated chemicals is a highly effective removal 

process. For alkenes, the hydroxyl radical adds to give a highly energetic product radical. The 

energetic product can then either revert back to products, or it can be stabilized by collision with 

another molecule which can carry off the excess energy. The reverse reaction is probably not 

important below 100°C. Hydroxyl free radicals can also add to a triple bond and to aromatics. 

In general, halocarbons require one of the groups carbonyl, conjugated double bonds, 

double bond conjugated to aromatic, polynuclear aromatic, nitro aromatic, or bromine/iodine to 

be present for there to be significant absorption and photodissociation in the troposphere. All of 

the proposed compounds contain bromine; otherwise, only carbonyls are of major interest in the 

proposed research as far as photolysis is concerned. 

The only chemicals exhibiting rapid reaction with tropospheric ozone are the alkenes. 

Removal by tropospheric ozone is expected to be significant for these compounds. The 

mechanisms of these reactions are not well understood, and the potential for reaction of highly 

fluorinated alkenes with tropospheric ozone is uncertain. For a globally averaged tropospheric 

ozone concentration of [O3] = 5.0 x 1011 molecules/cm3 and using a maximum repeated rate 

constant of 2 x 10-16 cm3/molecule-s reported in the literature, one calculates a first-order 

reaction rate constant of k1 = (kO3)[O3] = 1 x 10-

4

. This allows a calculation for alkenes for the 

atmospheric lifetime of t1/e = 1/k1 = 104 seconds or less than one day. Thus, removal by 

tropospheric ozone could be significant for alkenes. Generally, estimates of the atmospheric 

3
lifetime of alkenes focus entirely on the hydroxyl radical reaction rate constant and ignore the 

ozonolosis reaction. 

Table 2

Table 2. Tropospheric Removal Mechanisms

lists the various removal mechanisms and the families that are likely to have 

significantly decreased tropospheric lifetimes due to each mechanism.

Primary removal mechanism Example families 

Photodegradation Iodides, Carbonyls, Bromides 

Reaction with Hydroxyl Alkenes, Aromatics, HydrogenContaining Amines, Hydrogen-Containing 

Ethers, Carbonyls 

Physical Removal Ketones, Alcohols, Esters 

Reaction with Tropospheric Ozone Alkenes 

The successful development of a halon replacement is predicated on the identification of 

all critical parameters needed for eventual SNAP approval as well as those parameters central to 

the intended fire and explosion inertion and suppression application(s). The compound selection 

criteria employed in this project reflect current toxicity and environmental concerns and overall 

were the result of an evolving understanding of desired halon replacement properties. 

This project identified and acquired several tropodegradable compounds (primarily 

alkenes) estimated to satisfy the requirements of a Halon 1301 replacement. The compound 

properties reviewed or estimated included toxicity, boiling point, fire extinguishment 

performance, and tropospheric lifetime. 

Commercial chemical companies and institutes of chemical science in Russia and the US 

were provided with lists of the compounds of interest and quotes for synthesis were requested. 

Commercially available and synthesizable compounds were obtained and evaluated. 

Extinguishment tests run on the acquired compounds employed the NMERI cup-burner. 

4
B. PROJECT TASKS 

In order to advance the study of tropodegradable bromocarbon extinguishants as possible 

Halon 1301 replacements three tasks were identified and undertaken. The development of lists 

of potential tropodegradable bromocarbons preceded this effort as has the identification of 

chemical syntheses and some commercial sources of compounds. Earlier studies compiled 

toxicity information, atmospheric lifetime estimates, and preliminary lists of potential 

compounds of interest [1, 2]. Despite these assets few tropodegradable compounds had actually 

been acquired and had their flame extinguishment properties evaluated. The lack of actual flame 

extinguishment data (and toxicity test data) greatly slowed earlier efforts in the area of halon 

replacement research. 

Three basic tasks identified to advance research in this area are identified briefly below. 

Task 1. Compound selection. 

Of critical importance in the selection of candidate compounds is an adequate 

understanding of chemical compositional and structural factors contributing to compound 

toxicity and extinguishment capability. Target compounds were evaluated and promising 

candidates identified. The compound properties reviewed or estimated included toxicity, boiling 

point, fire extinguishment performance, and tropospheric lifetime. Toxicity estimates are based 

on toxicity literature, toxicology databases and anesthesiology reports. Promising 

tropodegradable compounds were selected based on either known or predicted properties and 

subsequently procured or synthesized. Toxicity and anesthesiology literature review coupled 

with results from Quantitative Structure-Activity Relationships (QSAR) and Quantitative 

Structure-Property Relationships (QSPR) computational evaluations of chemical properties were 

employed to identify tropodegradable compounds with promise as Halon 1301 replacements. In 

all cases, the compounds selected are predicted to have low tropospheric lifetimes (on the order 

of days), low toxicities (LC50 comparable to that of Halon 1301), fire extinguishing 

concentrations as measured by the cup-burner method of no more than 5 vol.% in air, and boiling 

points generally below 50°C. 

5
Table 3

Table 3. Targeted Halon 1301 Replacement Criteria 

lists initial targeted performance criteria for Halon 1301 replacement candidate 

compound physical, environmental, and toxicological properties. These criteria, are similar to 

those employed in the selection of streaming agent replacements.* 

Attribute Guideline

Boiling Point Dependent on application 

temperature (<50°C) 

LC50 (4-hour) > 50,000 ppm (5.0%) 

Cup-Burner Ext. Concentration < 5.0% 

Ozone Depletion Potential < 0.02a

Global Warming Potential < 5,000b

Atmospheric Lifetime << 0.1 years 

Cardiac Sensitization – No 

Adverse Effect Level 

> 2 times the cup-burner value 

a

With respect to CFC-11 

b

With respect to CO2 

Task 2. Acquisition - Synthesis and Characterization 

A survey of commercial and academic sources of chemical synthesis expertise was 

performed and lists of selected bromofluoro-alkenes, bromofluoro-ethers, and bromofluoroamines were sent to all potential sources of synthetic support. Synthetic pathways to the 

compounds of interest were in some cases identified and tested in order to support the synthesis 

efforts being made by suppliers [2]. 

Task 3. Cup-Burner Testing 

Extinguishment performance of selected tropodegradable bromocarbons was conducted 

using the NMERI Standard Cup-Burner. Use of this cup burner significantly reduces the cost of 

compounds and provides a reliable means of quickly screening compounds to determine flame 

 

*Juan A. Vitali, Applied Research Assoc., personal correspondence to J. Douglas Mather, NMERI, February 1997. 

6
extinguishment performance. NMERI Cup-burner test methods developed in earlier halon 

replacement efforts require approximately 50g of the test compound and give significantly less 

scatter than an apparatus similar to the ISO burner.* Subsequent modifications to the standard 

method were developed in the course of this research effort. The modified method involves 

introducing premixed agent/air mixtures into the flame zone. This permits flame extinguishment 

characterization of with as little as 2 to 5 grams of a chemical depending on molecular weight 

and actual cup-burner flame extinguishment performance. Observed flame extinguishment 

concentration values were employed in the ongoing review and compound selection process. 

C. TECHNICAL PROBLEMS 

The acquisition of chemicals, most of whom have never been synthesized, is very costly 

and very time consuming. In order to minimize per compound costs a modification to cupburner test methods was developed as indicated in Task 3. This modification makes it possible 

to obtain an upper-bound value for the cup-burner extinguishment using as little as 2 grams of a 

test compound instead of the typical 50 gram requirement. This modification does not affect the 

utility of the resulting cup-burner value and in fact provides greater stability and accuracy in air 

concentration measurements and actual test conditions. This modification will be described in 

greater detail in Section 4, Detailed Description of the Project. 

D. GENERAL METHODOLOGY 

Alkene halocarbons are among the chemical groups identified as being tropodegradable 

and having low atmospheric lifetimes. The relative ease of syntheses and the low atmospheric 

lifetimes of bromofluoro-alkenes result in their being considered a very promising source of 

Halon 1301 replacement candidates. Alkenes react rapidly with tropospheric •OH radicals 

through addition to the double bond, a reaction that proceeds faster than H atom abstraction. In 

addition, the alkene double bond readily undergoes reaction with tropospheric O3 in a process 

referred to as “ozonolysis.” Both OH and ozonolysis reaction products are expected to be 

 

*Testing in our laboratory comparing cup burners of various sizes and types have shown this.

7
rapidly removed from the troposphere by rainout. This project focused most of its efforts on the 

identification, acquisition, and testing of bromofluoro-alkenes. 

Tropodegradable compounds, with an emphasis on bromofluoro-alkenes, were evaluated 

and a list of potential replacements was developed. Promising tropodegradable compounds were 

selected based on either known or predicted properties and subsequently procured or 

synthesized. The compound properties reviewed or estimated included toxicity, boiling point, 

fire extinguishment performance, and atmospheric lifetime. Toxicity estimates were attempted 

using QSPR/ QSAR, toxicity literature, and anesthesiology reports. Toxicity, cup-burner 

performance, and atmospheric lifetime estimates were made on these and similar compounds. 

Synthetic routes for the compounds of interest were investigated, starting materials were 

determined, and several compounds were synthesized. Commercial chemical companies and 

institutes of chemical science in Russia were provided with lists of the compounds of interest 

and quotes for synthesis were requested. Extinguishment tests run on the selected compounds 

utilized the NMERI Standard Cup-burner. 

E. TECHNICAL RESULTS 

Tropodegradable bromofluoro-alkenes were evaluated in fire suppression tests during the 

program. The results of laboratory cup-burner tests with the tropodegradable bromofluoroalkene, 2-bromo-3,3,3-trifluoropropene (CH2=CBrCF3) demonstrated fire extinguishment 

performance close to that of Halon 1301, Table 4 and Table 5. 

Extinguishment test results and (limited) toxicity information show the potential of 

tropodegradable bromofluoro-alkenes as Halon 1301 replacements. Future work should continue 

to focus on these compounds. 

8
Table 4. Tropodegradable Brominated Halocarbon Cup-burner Values 

CCOD 

ID 

Compound, Formula Boiling 

point (°C) 

Cupburner 

(%) 

707 1-Bromo-3,3,3-trifluoropropene, CF3CH=CHBr 40 3.5*

872 3-Bromo-3,3-difluoropropene, CBrF2CH=CH2 42 4.5

873 2-Bromo-3,3,3-trifluoropropene, CF3CBr=CH2 34 2.6

903 4-Bromo-3,3,4,4-tetrafluorobutene, CF2BrCF2CH=CH2 54 3.5

1116 2-Bromo-3,3,4,4,4-pentafluorobutene, CF3CF2CBr=CH2 56 3.8*

1358 2-Bromo-3,3,4,4,5,5,5-heptafluoropentene,

CF3CF2CF2CBr=CH2

78 3.7*

1359 2-Bromo-3-trifluoromethyl-3,4,4,4-tetrafluorobutene, 

CF3CF(CF3)CBr=CH2

78 3.3*

1360 2-Bromo-3-trifluoromethoxy-3,4,4,4-tetrafluorobutene, 

CF3CF(OCF3)CBr=CH2

75 3.8*

1391 1-Bromo-2-trifluoromethyl-3,3,3-trifluoropropene, 

(CF3)2C=CHBr 

63 2.6*

1413 1-Bromo-4,4,4,3,3-pentafluorobutene,

CF3CF2CH=CHBr 

58 3.1*

*Testing performed using premixed agent/air mixtures all others involved mixing of 

separate air/agent flows 

9
Table 5. Tropodegradable Bromofluoro-Amines 

CCOD 

ID** 

Compound, Formula Boiling 

point 

°C 

Cupburner 

(%) 

1392 Bis(trifluoromethyl)-2-bromo-1,2,2-trifluoroethyl

amine, N(CF3)2(CHFCF2Br) 

72 

1393 Bis(trifluoromethyl)-2-bromo-1,1,2-trifluoroethyl

amine, N(CF3)2(CF2CFHBr) 

72 

2.4* 

1398 Bis(trifluoromethyl)-2-bromo-2-fluoroethylamine,

N(CF3)2(CH2CF2Br) 

80 2.4

Testing performed using premixed agent/air mixtures 

* Results of a 60/40 blend of CCOD’s 1392 and 1393 

** NMERI Chemical Compound Options Database ID 

F. IMPORTANT FINDINGS 

The findings to date continue to be promising. Cup-burner extinguishment data and 

limited toxicity data both are encouraging and several of the bromofluoro-alkenes and the 

bromofluoro-amines demonstrated flame extinguishment performance comparable to Halon 

1301. By far, bromofluoro-alkenes are the easiest group of compounds to acquire while 

bromofluoro-amines are the most difficult and expensive. 

G. SIGNIFICANT HARDWARE DEVELOPMENT 

The NMERI Cup-burner as originally designed employed a gravimetric method for 

dispensing liquid agents into the cup-burner base where an air stream aided by heating 

evaporated the agent as quickly as it is added. This method required approximately 50 to 100 

grams of test agent depending on the agents density and extinguishment properties. This method 

was revised to employ premixed agent air mixtures of air and agent which decreased the amount 

of material required and hence the cost of performing this test. The agent/air mixture is 

contained in a 10L Tedlar gas sample bag which is itself housed within an airtight rigid 

container. The container is penetrated by a sample line which connects to the Tedlar bag and a 

second line which simply penetrates into the air space between the bag and the inner wall of the 

rigid container. Detailed drawings are provided in Section III. 

10
H. SPECIAL COMMENTS 

Very few commercial or academic laboratories are willing to entertain the challenge of 

synthesizing unknown compounds. Environmental regulations have eliminated a lot of the small 

molecule starting materials required to attempt synthesis of compounds of interest and have also 

significantly driven-up the cost of acquiring chemicals. Consolidation of the commercial 

fluorochemical synthesis companies has greatly reduced the number of sources of synthetic 

expertise. All of these factors greatly limit the number of compounds that can be obtained and 

tested. 

I. IMPLICATIONS FOR FURTHER RESEARCH 

In this project, bromofluoroalkenes were the primary focus of compound selection, 

acquisition and testing efforts due to their promising toxicity, flame suppression, short 

atmospheric lifetime, and acceptable physical properties. Data from the RTECS database as well 

as acute inhalation toxicity and subsequent AMES test data for several of the bromofluoro 

alkenes of interest here is very promising. 

This project has resulted in the identification and acquisition of a number of 

tropodegradable bromofluoro-alkenes and bromofluoro-amines with expected low atmospheric 

lifetimes and demonstrated flame extinguishment performance. Their expected short 

atmospheric lifetimes translate directly into very low ozone depletion and global warming 

potentials. Some of these compounds were evaluated in acute inhalation toxicity exposures at 

5% (vol./vol.) for 30 minutes, Table 6[5]. The results of this test were very promising as three of 

the bromofluoro-alkenes evidenced no mortality and no changes in lung tissue appearance or 

weight. 

Flame extinguishment testing of several bromofluoro alkenes have yielded cup-burner 

values comparable to those of halon 1301 and 1211. Finally, synthetic methods, in some cases, 

are expected to enable relatively low cost manufacture of selected bromofluoroalkenes and give 

hope to the potential for low cost industrial preparation of others. 

11
Table 6. Acute Inhalation Data for Tropodegradable Alkenes 

CCO

D ID 

Compound Formula Mortality Lung Tissue

Condition 

873 2-Bromo-3,3,3-trifluoropropene CH2=CBrCF3 0 Normal

707 1-Bromo-3,3,3-trifluoropropene CHBr=CHCF3 0 Normal

872 3-Bromo-3,3-difluoropropene CH2=CHCBrF2 7 Mottled

903 4-Bromo-3,3,4,4-

tetrafluorobutene 

CH2=CHCF2CBrF2 0 Normal

1116 2-Bromo-3,3,4,4,4-

pentafluorobutene 

CH2=CBrCF2CF3 0 Mottled

1360 2-Bromo-3-trifluoromethoxy3,4,4,4-tetrafluorobutene CH2=CBr(OCF3)CFC

F3

10 Mottled

1358 2-Bromo-3,3,4,4,5,5,5-

heptafluoropentene 

CH2=CBrCF2CF2CF3 1 (post

exposure) 

Mottled 

1359 2-Bromo-3-trifluoromethyl3,4,4,4-tetrafluorobutene CH2=CBrCFC(CF3)2 10 Marked

mottling 

It is recommended that future work continue the acquisition of these compounds, with an 

emphasis on those with low boiling points, in quantities sufficient to allow flame extinguishment 

performance characterization. Toxicity screening studies leading to the selection of several 

compounds judged to have a high probability of meeting all SNAP requirements should be 

followed by manufacturing evaluations to select the least costly chemical(s) for the final phase of 

toxicity testing and development. 

12
SECTION II. 

BIBLIOGRAPHY 

A. PAPERS PRESENTED 

Tapscott, R.E., and Mather, J.D., “Research on Main Group Element Compounds and 

Tropodegradable Halocarbons as Halon Substitutes,” Proceedings, Fire Suppression and 

Detection Research Application Symposium, Orlando, National Fire Protection Research 

Foundation, 1999. 

Mather, J.D., and Tapscott, R.E., “Tropodegradable Halocarbons and Main Group Element 

Compounds,” Proceedings of the 1999 Halon Options Technical Working Conference, 

Albuquerque, 1999. 

Tapscott, R.E and Mather, J.D., “Tropodegradable Fluorocarbon Replacements for Ozone 

Depleting and Global Warming Chemicals, International Conference on Fluorine Chemistry ’99, 

Tokyo, 1999. 

13
SECTION III 

PROJECT DESCRIPTION 

A. COMPOUND SELECTION 

Three tasks were identified in order to accomplish the objectives of this project. These 

are: (1) to identify and select for acquisition promising tropodegradable fluorinated 

organobromine compounds; (2) acquire or synthesize identified compounds; and (3) to test the 

flame extinguishment capability of the acquired compounds. All targeted compounds in this 

effort were estimated to have acceptably low toxicity, ODP, and GWP for use as total flooding 

agents. 

The goal of the selection process is to identify compounds meeting the fundamental 

requirement of adequate to excellent flame extinguishment performance that also comply with 

standards of environmental performance in the areas of ozone depletion and global warming 

potential. Additionally, these compounds also needed to meet physical property requirements 

(boiling point, fill-density for drop in applications) related to the range of applications and 

delivery systems, and their toxicity must judged as not presenting undue hazard under the 

circumstances of use and handling i.e. normally occupied vs. unoccupied spaces. To this core of 

requirements could be added the eventual requirement that the finalist in this process of 

development must be manufacturable at a cost that is acceptable by the user. This project is 

focused only on the primary elements of the halon replacement selection process, those being 

estimated acceptable environmental, flame extinguishment performance, toxicity, and physical 

properties as the first step in the identification of a tropodegradable chemical as a Halon 1301 

replacement. 

Chemical families presented in an early list of tropodegradable compounds, reviewed by 

the AAWG, all contained functionalities which limit atmospheric lifetime through reaction with 

atmospheric •OH or O3 and or render the compound naturally prone to rainout, Table 7. 

14
Table 7. List of 26 Halon 1301 Replacement Candidates 

Formula Name

Alkenes 

CH2=CHCF2Br 3-bromo-3,3-difluoropropene

CF2BrCH=CHCF3 cis- and trans-1-bromo-1,1,4,4,4-pentafluoro-2-butene 

CF2BrCF2CH=CH2 4-bromo-3,3,4,4-tetrafluorobutene

CF2BrC(CF3)=CH2 3-bromo-3,3-difluoro-2-(trifluoromethyl)propene 

Alcohols 

CF2BrCH2OH 2-bromo-2,2-difluoroethanol

CF3CFBrCH2OH 2-bromo-2,3,3,3-tetrafluoropropanol

CF2BrCF2CH2OH 3-bromo-2,2,3,3-tetrafluoropropanol

CF3CHOHCH2Br 3-bromo-1,1,1-trifluoro-2-propanol

Ethers 

CF2H-O-CFHBr (bromofluoromethyl)(difluoromethyl)ether

CF2Br-O-CH3 (bromodifluoromethyl)(methyl)ether

CF2BrCH2-O-CF3 (2-bromo-2,2-difluoroethyl)(trifluoromethyl)ether

CF2BrCF2-O-CH3 (2-bromo-1,1,2,2-tetrafluoroethyl)(methyl)ether

-CH2CF2CBrFCH2-O- 3-bromo-2,2,3-trifluorooxolane

Amines 

(CBrF2)(CHF2)2N bis(difluoromethyl)(bromodifluoromethyl)amine

(CBrF2)(CF3)(CH3)N (bromodifluoromethyl)(trifluoromethyl)(methyl)amine

(CF3)2(CH2CBrF2)N bis(trifluoromethyl)(2-bromo-2,2-difluoroethyl)amine

(CBrF2)(CF3)2N bis(trifluoromethyl)(bromodifluoromethyl)amine

Carbonyl Compounds 

CBrF2CH2C(O)H 3-bromo-3,3-difluoropropanal

CH3C(O)CH2CF2Br 4-bromo-4,4-difluoro-2-butanone

CBrF2CH2C(O)OCH3 methyl 3-bromo-3,3-difluoropropionate

CBrF2CH2C(O)OCF3 trifluoromethyl 3-bromo-3,3-difluoropropionate 

Aromatics 

C6F5Br bromopentafluorobenzene

C6F5CBrF2 (bromodifluoromethyl)pentafluorobenzene

C6BrF4CF3 2-bromoheptafluorotoluene

3-bromoheptafluorotoluene 

4-bromoheptafluorotoluene 

15
The AAWG review of these chemical families yielded the recommendation that several 

be dropped from further consideration, primarily for toxicity and or physical property reasons. 

The compound groups selected for study in this project were in order of decreasing 

promise the bromofluoro-alkenes, the bromofluoro-ethers, and bromofluoro-amines. Each of 

these groups is discussed in the balance of this section with respect to estimates of flame 

extinguishment, toxicity, atmospheric lifetime, and relevant physical properties. 

1. Alkene toxicity information reviewed 

Some general (but not universal) toxicity trends shown in Table 8 have been used to 

provide a relative toxicity ranking for the candidate compounds and compound groups (alkenes, 

ethers, cyclics etc.)* 

Table 8. General Toxicity and Cardiac Sensitization Rules 

Toxicity Ranking Criteria

Aromatics are more toxic than aliphatics. 

Asymmetric molecules are more toxic than symmetric. 

Straight (carbon) chains are more toxic than branched. 

Ethers are more toxic than alkanes. 

Short chain ethers are more toxic than long chain ethers. 

Vinyl ethers are more toxic than saturated ethers. 

Polyoxy ethers are more toxic than mono ethers. 

Cardiac Sensitization Ranking Criteria

Halogen presence is more potent than hydrogen. 

Bromine presence is more potent than fluorine presence. 

 

*Allen Vinegar, ManTech Environmental Technology Inc., Dayton, Ohio, personal 

correspondence to Robert E. Tapscott, New Mexico Engineering Research Institute, The 

University of New Mexico, Albuquerque, New Mexico, May 1997. 

16
Approximate Lethal Concentration (ALC) data Table 9 [6] indicate that for 

halogenated ethenes, toxicity increases with increasing halogen substitution and that chlorine 

substitution gives a higher toxicity than does fluorine substitution. Note that for alkanes, toxicity 

is observed to first increase and then decrease with increasing fluorine substitution. For 

example, perfluoroalkanes and non-fluorinated alkanes are generally less toxic than the 

hydrofluoroalkanes. 

Table 9. ALC Values for Halogenated Amines. 

Compound name Compound formula a

ALC, ppm

Fluoroethene CH2=CHF >800,000

1,1-Difluoroethene CH2=CF2 >128,000

Tetrafluoroethene CF2=CF2 40,000

Chlorotrifluoroethene CF2=CClF 4,000

1,1-Dichloro-2,2-difluoroethene CF2=CCl2 1,000

a

One exposure of 4 to 19 hours. 

A compilation of the inhalation toxicity of all halogenated compounds listed in 

the Registry of Toxic Effects of Chemical Substances (RTECS) database was reviewed.* This 

information was accessed through the Chemical Abstracts STN service. LC50 and LCLO data for 

selected halogenated compounds, tropodegradable alkenes, and ethers were complied from this 

information and are presented in Table 10 and Table 11. 

 

*Lawrence R. Grzyll, Mainstream Engineering Corporation, Rockledge, Florida, personal 

correspondence to J. Douglas Mather, New Mexico Engineering Research Institute, The 

University of New Mexico, Albuquerque, New Mexico, April 1997. 

17
Table 10. Selected Inhalation LC50 Toxicity Information. 

CAS No. Compound name Species Durationa LC50, ppm

20591-32-6 2-Bromo-1,1,1,4,4,4-hexafluoro-2-butene Mouse 1H 5,000

11111-49-2 Dichlorohexafluorobutene Rat 4H 16

“ Mouse 4H 26

“ Dog 4H 182

2418-21-5 trans-2,3-Dichloro-1,1,1,4,4,4-hexafluoro2-butene Mouse 1H 61

706-79-6 1,2-Dichlorohexafluorocyclopentene Mouse 2H 210

677-21-4 3,3,3-Trifluoropropene Mouse 2H 430,676

434-64-0 Octafluorotoluene Rat 1H 1141

392-56-3 Hexafluorobenzene Mouse 2H 12,487

382-21-8 Perfluoroisobutylene Rat 6H 0.50

382-10-5 3,3,3,4,4,4-Hexafluoroisobutylene Rat 4H 1,425

360-58-7 Ethylheptafluoroisobutenyl ether Mouse NR 4,976 

344-07-0 Chloropentafluorobenzene Rat 4H >59

303-04-8 2,3-Dichlorohexafluoro-2-butene Rat 4H 16

“ Mouse 4H 26

“ Dog 4H 182

116-15-4 Hexafluoropropene Rat 4H 1825

“ Mouse 4H 750

116-14-3 Perfluoroethene Rat 4H 40,000

“ Mouse 4H 34,963

392-56-3 Perfluorobenzene Mouse 2H 12,500

336-19-6 1,2-Dichloro octafluorocyclohexene Mouse 2H 76

79-35-6 1,1-Dichloro-2,2-difluoroethylene Rat 4H 93

11111-49-2 Dichlorohexafluorobutene Rat 4H 16

79-38-9 Chlorotrifluoroethylene Rat 4H 1,000

18
Table 11. Selected RTECS Alkene LCLO Inhalation Toxicity Information. 

CAS No. Compound name Species Durationa LCLO, ppm

2356-01-6 1-(2',2',2'-Trifluoroethoxy)nonafluoro

cyclohexene 

Mouse 15M 19,000

1759-60-0 Monomethoxyheptafluorocyclopentene Mouse NR 12,000

2418-22-6 cis-2,3-Dichlorohexafluoro-2-butene Mouse 1H 179

697-11-0 Hexafluorocyclobutene Mouse NR 50,000

647-53-0 Monomethylnonafluorocyclohexene Mouse NR 8,000

598-73-2 Bromotrifluoroethene Rat 4H 279

434-64-0 Perfluorotoluene Mouse 10M 5,000

360-89-4 Octafluoro-2-butene Mouse 4H 6,100

355-75-9 Decafluorocyclohexene Mouse NR 8,000

79-47-0 3-Chloropentafluoro-3-propene Rat NR 27

2418-22-6 2,3-Dichlorohexafluoro-2-butene Mouse 1H 179

a H = hours, M = minutes. NR indicates duration not reported. 

Experimental data for three bromofluoro-alkenes and fluoro-alkenes highlight the 

potential for these lower molecular weight compounds to meet toxicity requirements for a Halon 

1301 replacement. Toxicity information for these three compounds is presented below. 

3,3,3-Trifluoropropene has been reported to have a 2-hour mouse LC50 of 430,676 ppm, 

. This is a rather impressive and hopeful result. A number of mono-brominated 

structural isomers can be easily envisioned based on this molecule. 

Table 10

More extensive information is available on 4-Bromo-3,3,4,4-tetrafluorobutene. This 

compound has been reported [7] to have a 4-hour ALC in rats greater than 19,300 ppm. The 

compound is not mutagenic in Ames bacterial assay, with and without metabolic activation, in 

strains TA 1537, TA 1538, and TA 98, and it is not clastogenic in Chinese Hamster Ovary 

(CHO) cell assay with and without metabolic activation. In a 2-week sub chronic study, male 

rats were exposed to concentrations of 0, 1000 or 10,000 ppm, 6 hours/day, 5 days/week for 2 

weeks. Clinical observations during exposure included a decreased response to sound and loss 

of coordination in rats exposed to 10,000 ppm. Rats in this group had significantly lower body 

19
weights than controls during the exposure period but showed a normal rate of weight gain during 

recovery period. Rats exposed to 1000 ppm showed a normal rate of weight gain throughout the 

study. Pathological examination showed no compound-related macroscopic or microscopic 

changes in any of the rats. The mean relative liver weight of rats exposed to 10,000 ppm was 

significantly higher upon comparison with controls after Exposure 10 but was in the normal 

range after 14 days recovery. Mean absolute spleen weights for rats in both test groups were 

significantly lower than those of controls after 14 days recovery. In the absence of any 

microscopic changes, the relevance of these organ weight changes is questionable. Clinical 

chemistry measurements showed that rats exposed to 1,000 ppm excreted more fluoride than 

controls following exposure while rats exposed to 10,000 ppm showed an increase in both 

concentration and in the total amount of urine excreted. 

2-Bromo-3,3,3-trifluoropropene, CH2=CBrCF3, has been reported to be an “excellent 

anesthetic with a rapid, uneventful recovery” in exposures of dogs [8]. It is impossible to 

determine the anesthetic potency of this chemical since the concentrations used were not 

reported; however, since anesthesia was attained and no adverse effects were observed, this 

material appeared to have a low acute inhalation toxicity (this conclusion was later confirmed in 

testing). 2-Bromo-3,3,3-trifluoropropene is one of two bromine adducts of 3,3,3-

trifluoropropene whose low inhalation toxicity, , is discussed above. Based on these

results the mono-brominated trifluoro- and possibly tetrafluoro- three carbon alkenes appear to 

be a promising area for consideration as halon replacement candidates. There is no evidence that 

the mono-bromo tetrafluoro- and pentafluoro-butenes should not also be considered promising. 

Table 10

3-Bromo-3,3-difluoropropene’s rat ALC is 10,000 ppm all four animals in this test died 

in the last hour of the 4-hour exposure. It is expected that compounds in which the bromine is 

alpha to the double bond will be more likely to form allyl cations (Reference 9). These cations 

could contribute to toxicity. 

20
2. Amine Toxicity Information Reviewed 

The acute inhalation toxicity of some fluorinated alkyl amines are give in Table 12.* In 

addition to these, the LCLO for mouse inhalation has been reported as 500 mg/m3

 for 2,2,2-

trifluoroethylamine ((CF3CH2)NH2, CAS No. = 753-90-2, SAX No. = TKA500) with a SAX 

Hazard Rating (HR) of 2, [10]. 

TABLE 12. ACUTE INHALATION TOXICITY OF HFAs. 

Compound LC50, mg/L Conditions 

(CF3)2NCH3 >20 3-Hour rat

(CF3)2NCF2CF2H >20 3-Hour rat

(CF3)2NCFHCF3 >20 3-Hour rat

(CF3)2NCH2CF3 >20 3-Hour rat

(CF3)2NCH2CF2H >20 4-Hour rat

(CF3)2NCH2CH3 >20 4-Hour rat

3. Ether Toxicity Information Reviewed 

Ethers have relatively low toxicities due to the low reactivity of the C–O–C functional 

group arising from the high strength of the C–O bond. Volatile ethers can affect the CNS, 

however, flammability and the formation of explosive peroxides tend to be more serious 

problems than toxicity. Table 13, Table 14,† and Table 15 indicate that most of the HFEs 

exhibit relatively low toxicities and are not mutagenetic. 

 

*Misaki, S., and Sekiya, A., “Development of a New Refrigerant,” presented at the International 

Chemical Congress of Pacific Basin Societies, Honolulu, Hawaii, 17-22 December 1995. 

†Misaki, S., and Sekiya, A., “Development of a New Refrigerant,” presented at the International 

Chemical Congress of Pacific Basin Societies, Honolulu, Hawaii, 17-22 December 1995. 

21
TABLE 13. TOXICITY OF ETHERS 

Formula a

Hazard rating bToxicity comments 

CF2HOCF2H c No toxicity data available. 

CF2HOCHF3 c No toxicity data available. 

CF2HOCF2CHFCl 2 Used as an anesthetic under names enflurane and 

enthrane. Mildly toxic by inhalation, ingestion, and 

subcutaneous routes. 

CF3CHClOCHF2 c Used as an anesthetic under name isoflurane. 

C4F9C4F7O c Used as blood substitute. 

CF2BrOCF2Br c No toxicity data available. 

CF2BrOCF3 c No toxicity data available. 

CF2BrOCF2CHFCl c No toxicity data available. The non-brominated 

version is an anesthetic known as enflurane. 

C5F8O c No toxicity data available. The perfluorobutyl 

substituted compound is used as a blood substitute, 

and the toxicity of this compound may be 

acceptable. 

C4F7BrO c No toxicity data available. 

a

[10], b[11], cNot available. 

22
TABLE 14. TOXICITY OF HFEs. 

Compound a,bAcute oral 

LD50, mg/kg 

Acute 

inhalation 

LC50, mg/L 

a,cMutagenicity, 

Ames test 

Skin irritation, 

rabbit 

CH3OCH2CH2F <30 0.5-2.0 mg/L Negative Not available 

CH3OCF2CHF2 >300 >20 Negative Non-irritant

CHF2OCF2CH2F >300 >20 Negative Non-irritant

CH3OCF2CF2CF3 >300 >20 Negative Non-irritant

CHF2OCH2CF2CF3 >300 >20 Negative Non-irritant

CH3OCH(CF3)2 >300 >20 Negative Non-irritant

CH3CH2OCF2CHF2 >300 >20 Negative Slight irritant

CF3CH2OCF2CHF2 >300 >20 Negative Non-irritant

a

 Misaki, S., and Sekiya, A., “Development of a New Refrigerant,” presented at the 

International Chemical Congress of Pacific Basin Societies, Honolulu, Hawaii, 

17-22 December, 1995.

b

Rat, 2 doses. The authors of the paper cited consider an LD50 < 30mg/kg to be toxic. 

c

Rat, 4-hour. The authors of the paper cited consider an LC50 of 0.5-2.0 mg/L to be toxic. 

TABLE 15. HFE TOXICITY EVALUATION. 

Compound Toxicity evaluation

CH3OCF(CF3)2 Acute inhalation, 3% for 4 hours: no observable effects 

Subacute inhalation, 6 hr/day for 7 days: NOAEL >2.0g/m3

CH3OCF2CF3 Acute inhalation, 3% for 4 hours: no observable effects 

Inhalation test, 28 days: NOAEL >20.0 g/m3

Ames test: Negative 

Chromosome aberration: Negative 

CH3OCF2CF2CF3 Acute inhalation, 3% for 4 hours: no observable effects 

Acute oral: LD50 > 2 g/kg 

Ames test: Negative 

Subacute inhalation: 6 hr/day for 7 days: NOAEL 7.0 g/m3

23
4. Atmospheric lifetime estimates for alkenes 

Estimates of atmospheric lifetime were developed and reported in an earlier 

publication a synopsis of which is presented in this subsection [1]. Comparison of these 

estimates reveals a striking differences between the three favored candidate families. 

TABLE 16. ATMOSPHERIC LIFETIMES AND ODP VALUES FOR COMMON HCFCs 

AND CFCs. 

Halocarbon 

number 

IUPAC name Formula Lifetime, 

years 

ODP 

HCFC-141b 1,1-dichloro-1-fluoroethane CH3CCl2F 9.4 0.1

HCFC-124 2-chloro-1,1,1,2-

tetrafluoroethane 

CHClFCF3 5.9 0.03

HCFC-123 2,2-dichloro-1,1,1-

trifluoroethane 

CHCl2CF3 1.4 0.014

HCFC-225ca 3,3-dichloro-1,1,1,2,2-

pentafluoropropane 

CF3CF2CHCl2 2.5 0.02

HCFC-225cb 1,3-dichloro-1,1,2,2,3-

pentafluoropropane 

CClF2CF2CHClF 6.6 0.02

HCFC-22 chlorodifluoromethane CHClF2 13.3 0.04

HCFC-142b 1-chloro-1,1-difluoroethane CH3CClF2 19.5 0.05

CFC-11 trichlorofluoromethane CCl3F 50 1

CFC-12 dichlorodifluoromethane CCl2F2 102 0.82

CFC-13 chlorotrifluoromethane CClF3 640 1

CFC-113 1,1,2-trichloro-1,2,2-

trifluoroethane 

CCl2FCClF2 85 0.9

CFC-114 1,2-dichloro-1,1,2,2-

tetrafluoroethane 

CClF2CClF2 300 0.85

CFC-115 chloropentafluoroethane CClF2CF3 1700 0.4

The reaction rates of haloalkenes with hydroxyl radicals range from approximately 10-13

to 10-11

 cm3/molecule-s compared with approximately 10-15 to 10-12 cm3/molecule-s for saturated 

24
halocarbons 12.* On an average, the reactions are about 100 times faster for alkenes than for 

alkanes, and the atmospheric lifetimes are reduced accordingly. Thus, based on an atmospheric 

lifetime on the order of 10 years for a typical HCFC, Table 16, one would predict atmospheric 

lifetimes of approximately 1/10 year (about 1 month) for a typical haloalkene. 

Estimates of reaction rate constants and atmospheric lifetimes using the method of 

Wuebbles and Connell several things should be noted [13]. This has been done for several 

alkenes, Table 17. First, the addition of fluorine atoms at the double bond increases the 

atmospheric lifetime. Second, lifetime decreases when alkyl groups are placed at the double 

bond. Finally, photodecomposition due to the presence of bromine and, to a lesser extent, the 

reaction of compounds containing hydrogen with tropospheric hydroxyl free radicals will lower 

the lifetimes. These approximations indicate that lifetimes for compounds of interest will range 

from 3 months down to less than a day. 

Removal by reaction with tropospheric ozone is also possible for alkenes. A number of 

halogenated alkenes have atmospheric lifetimes that range from less than 1 day to about 7 days 

as a result of the reaction with tropospheric ozone [14]. The reaction is faster when alkyl groups 

(but not totally fluorinated alkyl groups) are substituted at the double bond. 

Taking all of this into account, haloalkenes (more importantly, fluoroalkenes) are 

expected to have tropospheric lifetimes on the order of days due to reaction with hydroxyl free 

radicals and ozone, and this is likely to be even lower with bromine substitution [15]. 

 

*These rate constants are for 298 K (0 oC). This is a little higher than the actual average for 

tropospheric temperature; however, it is difficult to find reported or estimated rate constants at 

265 K, the temperature that is closer to the average. Unless reported otherwise, assume that all 

rate constants in this report are for 298 K or approximately this temperature. 

25
Table 17. Estimated hydrogen atom abstraction rate constants and alkene atmospheric lifetimes 

Compound K[•OH], s-1 Lifetime, days

CF2=CFBr 1.3 x 10-7 90

CF2=CFCF2Br 5.8 x 10-7 19

cis-CF3CF=CFCF2Br 2.2 x 10-6 5.4

trans-CF3CF=CFCF2Br 2.5 x 10-6 4.6

(CF3)2C=CFCF2Br 4.8 x 10-6 2.4

(CF3)2C=C(CF3)CF2Br 1.5 x 10-5 0.8

CH2=CFBr 3.6 x 10-7 32

(CF3)2C=CHCF2Br 8 x 10-6 1.4

For the initial acquisition effort selection of candidate bromofluoro-alkenes, for 

acquisition and cup-burner evaluation, employed the following general guidance. Compounds 

were limited to three, four and five carbon alkene structures. Fluorination of each structure was 

limited to the non-vinylic positions. Selected molecules were partially fluorinated such that the 

number of fluorine’s exceeds the number of hydrogens to ensure non-flammability. Bromination 

sites avoided the allylic position. These guidelines ensured that only non-flammable compounds 

would be acquired and eliminated the higher boiling alkenes from consideration. They also 

avoided the possibility of toxicity associated with the allylic bromination site, and avoided, for 

the time being, the possibility of flammability due to fluorination of vinylic sites. Examples of 

the compounds considered are presented in Table 18. 

26
Table 18. Partial List of Tropodegradable Alkenes 

IUPAC name Compound formula 

1-Bromo-2-trifluoromethyl-3,3,3,-

trifluoropropene 

(CF3)2C=CHBr 

1-Bromo-2-trifluoromethyl-1,3,3,3,-

tetrafluoropropene 

(CF3)2C=CFBr 

1-Bromo-3,3,3-trifluoropropene CF3CH=CHBr 

2-Bromo-3,3,3-trifluoropropene CF3CBr=CH2

2-Bromo-1,3,3-trifluoropropene CF2HCBr=CHF 

1-Bromo-2,3,3-trifluoropropene CF2HCF=CHBr 

1-Bromo-1,3,3-trifluoropropene CF2HCH=CFBr 

2-Bromo-1,3,3,3-tetrafluoropropene CF3CBr=CHF 

1-Bromo-2,3,3,3-tetrafluoropropene CF3CF=CHBr 

1-Bromo-1,3,3,3-tetrafluoropropene CF3CH=CFBr 

2-Bromo-3,3,4,4-tetrafluorobutene CF2HCF2CBr=CH2

1-Bromo-3,3,4,4-tetrafluorobutene CF2HCF2CH=CHBr 

4-Bromo-3,3,4,4-tetrafluorobutene CF2BrCF2CH=CH2

4-Bromo-2,3,3,4,4-pentafluorobutene CF2BrCF2CF=CH2

4-Bromo-1,3,3,4,4-pentafluorobutene CF2BrCF2CH=CHF 

2-Bromo-3,3,4,4,4-pentafluorobutene CF3CF2CBr=CH2

1-Bromo-3,3,4,4,4-pentafluorobutene CF3CF2CH=CHBr 

2-Bromo-3,3,4,4,5,5,5-heptafluoropentene CF3CF2CF2CBr=CH2

1-Bromo-3,3,4,4,5,5,5-heptafluoropentene CF3CF2CF2CH=CHBr 

5-Bromo-3,3,4,4,5,5-hexafluoropentene CF2BrCF2CF2CH=CH2

2-Bromo-3,3,4,4-tetrafluorobutene CF2HCF2CBr=CH2

5. Atmospheric lifetime estimates for ethers 

Estimates of atmospheric lifetime were developed and reported in an earlier publication a 

synopsis of which is presented in this subsection [1]. The atmospheric lifetimes of PFEs are very 

long, and there is little evidence that the presence of an oxygen atom (which would give a small 

increase in polarity) causes a significant decrease in atmospheric lifetime. On the other hand, the 

27
addition of hydrogen atoms makes hydrogen atom abstraction possible by hydroxyl free radicals. 

Moreover, the presence of an ether linkage increases the reaction rate. Insertion of an ether 

group alpha to the position from which hydrogen abstraction occurs should increase the rate 

constant. Moving a CF3 group out of this position also increases the rate constant 16. Indeed, 

data for a number of ethers show rate constants approximately 102 larger than similar 

hydrocarbons [12]. 

Lifetimes reported for HFEs vary widely. For example, pentafluorodimethyl ether, 

CHF2OCF3 (HFE-125) and bis(difluoromethyl)ether, CHF2OCHF2 (HFE-134) are reported to 

have atmospheric lifetimes of 82 years and 8 years [17]. The value for HFE-125 is particularly 

long. On the other hand, a recent report lists HFEs with atmospheric lifetimes as low as 0.3 

years.

*,† As expected, the atmospheric lifetimes decrease as the number of hydrogen atoms 

increase[1]. The presence of the oxygen atom makes the α-carbons hydrogens C-H bond weaker 

suggesting that for the same number of hydrogens those compounds with the largest number on 

α-carbons will have the lowest atmospheric lifetimes. Table 19 lists a number of ethers, those 

with the largest number hydrogens and greatest percentage on α-carbons are predicted to have 

the shortest atmospheric lifetimes. 

 

*Misaki, S., and Sekiya, A., “Development of a New Refrigerant,” presented at the International 

Chemical Congress of Pacific Basin Societies, Honolulu, Hawaii, 17-22 December 1995. 

†Grenvell, M. W., Klin,, F. W., Owns, J. G., and Yanome, H., “New Fluorinated Solvent 

Alternatives,” Precision Cleaning ‘95, Rosemont, Illinois, 15-17 May 1995. 

28
TABLE 19. Tropodegradable Ethers 

IUPAC name Compound formula Mol. 

Wt.

Hydrogens

α/Total 

1-Bromo-2-trifluoromethoxy-1,1-

difluoroethane 

CF3-O-CH2CF2Br 228.9 2/2

1-Bromo-2-trifluoromethoxy-1,1,2,2-

tetrafluoroethane 

CF2H-O-CFHCF2Br 228.9 2/2

1-Bromo-2-fluoromethoxy-1,1,2,2-

tetrafluoroethane 

CH2F-O-CF2CF2Br 228.9 2/2

1-Bromo-2-(1,2,2,2-

tetrafluoroethoxy)-1,1,2-

trifluoroethane 

CF3CFH-O-CFHCF2Br 278.9 2/2

1-Bromo-2-perfluoroethoxy-1,1-

difluoroethane 

CF3CF2-O-CH2CF2Br 278.9 2/2

1-Bromo-2-(2,2,2-trifluoroethoxy)-

1,1,2,2-tetrafluoroethane 

CF3CH2-O-CF2CF2Br 278.9 2/2

1-Bromo-2-(2,2-difluoroethoxy)-

1,1,2,2-tetrafluoroethane 

CF2HCH2-O-CF2CF2Br 260.9 2/3

1-Bromo-2-(2-fluoroethoxy)-1,1,2,2-

tetrafluoroethane 

CH2FCH2-O-CF2CF2Br 242.9 2/4

1-Bromo-2-fluoromethoxy-1,2-

difluoroethane 

CH2F-O-CFHCFHBr 192.9 3/4

1-Bromo-2-(2,2,2-trifluoroethoxy)-

1,1,2-trifluoroethane 

CF3CH2-O-CFHCF2Br 260.96 3/3

1-Bromo-2-difluoromethoxy-1,1-

difluoroethane 

CF2H-O-CH2CF2Br 210.95 3/3

1-Bromo-2-fluoromethoxy-1,1,2-

trifluoroethane 

CH2F-O-CFHCF2Br 210.95 3/3

1-Bromo-2-methoxy-1,1,2,2-

tetrafluoroethane 

CH3-O-CF2CF2Br 210.95 3/3

1-Bromo-2-(2,2-difluoroethoxy)-1,1,2-

trifluoroethane 

CF2HCH2-OCHFCF2Br 

242.97 3/4

1-Bromo-2-(2,2-difluoroethoxy)-1,1-

difluoroethane 

CF2HCH2-OCH2CF2Br 

224.98 3/5

1-Bromo-2-(2,2,2-trifluoroethoxy)-

1,1-difluoroethane 

CF3CH2-O-CH2CF2Br 242.97 4/4

29
Table 19 (continued). Tropodegradable Ethers 

IUPAC name Compound formula Mol. 

Wt.

Hydrogens

α/Total 

1-Bromo-2-methoxy-1,1,2-

trifluoroethane 

CH3-O-CFHCF2Br 192.96 4/4

1-Bromo-2-fluoromethoxy-1,1-

difluoroethane 

CH2F-O-CH2CF2Br 192.96 4/4

1-Bromo-2-(2,2,2-trifluoroethoxy)-

1,1-difluoroethane 

CF3CH2-O-CH2CF2Br 242.97 4/4

1-Bromo-2-(2,2-difluoroethoxy)-1,1-

difluoroethane 

CF2HCH2-OCH2CF2Br 

224.98 4/5

6. Atmospheric lifetime estimates for amines 

Estimates of atmospheric lifetime were developed and reported in an earlier publication a 

synopsis of which is presented in this subsection [1]. When hydrogen atoms are present on both 

an amine alkyl group and on the nitrogen, C-H abstraction tends to occur in preference to or in 

competition with N-H abstraction. The presence of a nitrogen atom decreases the C-H bond 

strength. Thus, the bond energies for C-H in CH4, CH3NH2, (CH3)2NH, and (CH3)3N are, 

respectively, 435, 391, 364, and 352 kJ/mol (104, 93.3, 87, and 84 kcal/mol) [18]). As would be 

expected from these data, a nitrogen atom alpha to a C-H bond significantly increases the 

reaction rate constant for hydrogen abstraction by hydroxyl free radicals. This can be seen in the 

comparison of rate constants between amines and structurally similar hydrocarbons [1]. For this 

limited set of data, the amine rate constants are 23 to 65 times large than the hydrocarbon rate 

constants. The calculated atmospheric lifetimes t1/e for mono-, di- and tri-methyl amines are less 

than 1 day based on their reactions with tropospheric hydroxyl free radicals only [1]. 

Limiting consideration to three, Table 20, and four, Table 21, carbon amines for the 

present potential candidates for acquisition can be readily identified and compared. Atmospheric 

life time is predicted to decrease for compounds further down each list. Potential toxicity due to 

the presence of brominated α-carbons is a concern in the selection process but data which would 

provide concrete guidance is lacking. 

30
TABLE 20. THREE CARBON TROPODEGRADABLE AMINES– NR1R2R3

Formula R1 R2 R3 Hydrogens

α/Total 

Mol. Wt. 

NC3F7HBr CF3 CF3 CFHBr 1/1 263.9

NC3F7HBr CF3 CF2H CF2Br 1/1 263.9

NC3F6H2Br CF3 CF2H CFHBr 2/2 245.9

NC3F6H2Br CF3 CF3 CH2Br 2/2 245.9

NC3F6H2Br CF3 CF2H CFHBr 2/2 245.9

NC3F6H2Br CF2H CF2H CF2Br 2/2 245.9

NC3F6H2Br CF3 CF3 CH2Br 2/2 245.9

NC3F5H3Br CF3 CF2H CH2Br 3/3 227.9

NC3F5H3Br CF3 CF2H CH2Br 3/3 227.9

NC3F5H3Br CF2H CF2H CFHBr 3/3 227.9

NC3F4H4Br CF2H CF2H CH2Br 4/4 209.9

TABLE 21. FOUR CARBON TROPODEGRADABLE AMINES– NR1R2R3 

Formula R1 R2 R3 Hydrogens

α/Total 

Mol. 

Wt.

NC4F9HBr CF3 CF3 CFHCF2Br 1/1 313.9

NC4F9HBr CF3 CF2H CF2CF2Br 1/1 313.9

NC4F8H2Br CF3 CF3 CFHCFHBr 1/2 295.9

NC4F8H2Br CF3 CF2H CFHCF2Br 2/2 295.9

NC4F8H2Br CF2H CF2H CF2CF2Br 2/2 295.9

NC4F8H2Br CF3 CF3 CH2CF2Br 2/2 295.9

NC4F7H3Br CF3 CF2H CFHCFHBr 2/3 277.9

NC4F7H3Br CF3 CF2H CFHCFHBr 2/3 277.9

NC4F6H4Br CF3 CF3 CH2CH2Br 2/4 259.9

NC4F7H3Br CF3 CF2H CH2CF2Br 3/3 277.9

NC4F7H3Br CF2H CF2H CFHCF2Br 3/3 277.9

NC4F6H4Br CF2H CF2H CFHCFHBr 3/4 259.9

NC4F5H5Br CF3 CF2H CH2CH2Br 3/5 241.9

NC4F4H6Br CF2H CF2H CH2CH2Br 3/6 223.9

NC4F6H4Br CF2H CF2H CH2CF2Br 4/4 259.9

α-Hydrogens are attached to those carbons directly bonded to amine nitrogens (i.e., H-C-N). 

7. Physical property estimates – boiling point effects 

A major criterion for any liquid to perform as a total flood agent is an ability to 

evaporate and fill a space to a required concentration within the time required for extinguishment 

31
under the ambient conditions. Thus, evaporation properties must be taken into account during 

compound review and selection in addition to a full understanding of the temperature range for 

application. Areas that must be considered are evaporation equilibrium and evaporation rate. 

An estimate of the effects of the boiling point on evaporation equilibrium and application 

temperature was partially undertaken under this project and a related project “Main Group 

Compounds as Extinguishants” also funded under the NGP program. This presentation can be 

found in full in the associated final project report for the NGP project “Main Group Compounds 

as Extinguishants” only the results are presented here. 

The question of whether a given compound can achieve the required 

extinguishment concentration is easily answered since only thermodynamics are involved. The 

logarithm of the ratio of the vapor pressure (p) at two different temperatures T2 and T1 can be 

estimated from the Clausius-Clapeyron equation. For closely related compounds, ∆Svap at the 

boiling point is nearly constant with a value of tc, Trouton’s constant. Thus, by selecting T1 as 

the boiling point (Tb) at, for example, 1 atmosphere pressure (i.e., p1 = 760 Torr), one can 

estimate the vapor pressure at some other temperature and develop an approximate vapor 

pressure/temperature curve if tc is known. Table 22 gives the estimated maximum boiling point 

Tb that can achieve concentrations from 1 vol.% to 20 vol.% for a Trouton constant of 

88 J/K-mol, (1). 

Tb = [1-(Log(C/100)/0.05221065tc)]T2 (1)

This analysis shows that a compound with a boiling point of over 100 °C can 

likely achieve a concentration of 5 vol.% at normal room temperature (25 °C). Whether such a 

compound can achieve such a concentration in a reasonable amount of time is, however, a quite 

separate question. The shaded region represents the lower end of the compound boiling points of 

those compounds acquired and tested in the course of this project and the projected application 

temperature limitations. 

32
TABLE 22. ESTIMATED MAXIMUM BOILING POINT THAT CAN ACHIEVE A GIVEN 

CONCENTRATION. 

Conc. Ambient Temperature, °C 

% -60 -50 -40 -30 -20 -10 0 10 20 30 40 50

1 33 47 61 76 90 105 119 133 148 162 176 191

2 19 33 46 60 74 87 101 115 128 142 156 169

3 11 24 37 51 64 77 91 104 117 130 144 157

4 5 18 31 44 57 70 83 96 109 122 135 148

5 0 13 26 39 52 65 77 90 103 116 129 142

6 -3 9 22 35 47 60 73 85 98 111 123 136

7 -6 6 19 31 44 56 69 81 94 106 119 131

8 -9 3 16 28 40 53 65 78 90 102 115 127

9 -11 1 13 25 38 50 62 74 87 99 111 124

10 -14 -1 11 23 35 47 59 72 84 96 108 120

11 -16 -3 9 21 33 45 57 69 81 93 105 117

12 -17 -5 7 19 31 43 55 67 79 91 103 115

13 -19 -7 5 17 29 41 53 65 77 88 100 112

14 -20 -9 3 15 27 39 51 63 74 86 98 110

15 -22 -10 2 14 25 37 49 61 73 84 96 108

16 -23 -11 0 12 24 36 47 59 71 83 94 106

17 -24 -13 -1 11 22 34 46 57 69 81 92 104

18 -25 -14 -2 9 21 33 44 56 68 79 91 102

19 -27 -15 -3 8 20 31 43 54 66 78 89 101

20 -28 -16 -5 7 19 30 42 53 65 76 88 99

B. COMPOUND SYNTHESIS AND ACQUISITION 

Synthetic efforts were directed to providing experimental quantities of the 

tropodegradable compounds from the bromofluoro-alkene, bromofluoro-amine, and 

bromofluoro-ethers. While synthesis approaches were readily identifiable actual laboratory 

synthesis efforts were inevitably constrained by the availability of required starting materials. 

33
Commercial chemical sources frequently required up to six months to synthesize and deliver 

chemicals project. 

In preparation for the planned compound synthesis effort, an extensive survey of 

database sources for information on existing bromofluoro-alkenes and methods for their 

synthesis was performed. The information obtained was carefully summarized and is presented 

in the following sections grouped according to the basic functionality of the molecular structure. 

1. Bromofluoro-alkenes 

An extensive literature search revealed that several bromofluoro-alkenes have been 

prepared by dehydrohalogenation of the appropriate partially fluorinated dibromopropanes with 

a base (e.g., Reaction 1) (Reference 19). Depending on the difficulty in preparing the starting 

materials, this is a fairly straightforward reaction. Other preparations following the same scheme

(References 20, through 22) and an improved procedure to prepare the precursors (Reference 23) 

have been reported. Many of the precursors are classified as Class 1 Ozone depleters and as 

such have all but disappeared from commercial catalogues. 

CBrF2CH2CH2Br + OH- → CBrF2CH=CH2 + H2O + Br- (1) 

A preparation has been reported for the dibrominated compound 2,3-dibromo-3,3-

difluoropropene [20]). Fluorination of this compound gives 2-bromo-3,3,3-trifluoropropene 

[20]. 3-Bromo-1,1-difluoropropene has been obtained in small amounts by reaction of 

hexafluorocyclopropane with vinyl bromide [24]). The preparation of 1-bromo-3,3,3-

trifluoropropene by dehydrohalogenation of CBrF2CH2CBrF2 has been reported [21]. A number 

of (mostly) higher molecular weight alkenes, some with multiple bromine atoms and some

containing chlorine, have been reported [25], [26]. 1-Bromo-1,1,2,2-tetrafluoro-3-pentene, 

boiling point 97 °C and 1-bromo-1,1,2,2-tetrafluoro-4-methyl-3-pentene, boiling point 116 °C 

have been prepared by dehydrohalogenation of 1,1,2,2-tetrafluoro-1,4-dibromopentane and 

1,1,2,2-tetrafluoro-1,4-dibromo-4-methylpentane, respectively [27 and 28]. 

Dehydrohalogenation reactions of brominated fluorinated alkanes involve the 

formation of an alkene by removal of HF or HBr from an incompletely halogenated alkane. The 

dehydrohalogenation reaction typically requires heating of the incompletely halogenated 

34
compound in the presence of potassium hydroxide. The reactions can be selective, yielding a 

single alkene product in high purity. 

Additional methods applicable to the synthesis of bromofluoro-alkenes include 

the Wittig reaction. This synthetic approach employs substituted methylenetriphenylphosphoranes, (C6H5)3P=CR1R2), where R1,2 = H, F, CF3, etc. Methylenetriphenylphosphoranes 

are reactive when combined with carbonyl containing compounds. The reaction results in 

replacement of the carbonyl oxygen (C=0) of the carbonyl compound with the methylene 

(CR1R2) group from the methylenetriphenylphosphoranes and yields an alkene product one 

carbon longer than the original carbonyl compound. 

The Wittig reaction has been demonstrated for numerous fluorine-containing carbonyl 

compounds and can provide high yields of product compounds. Triphenylphosphorane starting 

materials are not expensive, and the reaction conditions are not extreme. Compounds can be 

isolated and purified by standard methods. 

2. Bromofluoro-ethers 

The hydrobromofluoro-ether (HBFE) 1-bromo-1,1,2,2-tetrafluoro-6-ethoxyhexane, 

boiling point 67 oC has been isolated during dehydrohalogenation of 

CBrF2CF2CH2CH2CH2CH2Br with KOH in ethanol [25]. 1-Bromo-1,2,2-trifluoro-3-

methoxypropane, boiling point 125 oC has been prepared in a multi-step synthesis. 

Reactions of alkenes with CF3OF and CF3OCl has allowed preparation of HBFEs and a 

hydrobromochlorofluoroether (HBCFE) (Reference 29). 2-Bromo-1,1,2-trifluoro-1-

(trifluoromethoxy)ethane and 2-bromo-1,1,1-trifluoro-2-(trifluoromethoxy)ethane are provided 

by reaction of CF2=CHBr with CF3OF. The two regioisomers (CF3-O-CF2CHBrF and 

CF3CHBr-O-CF3) are difficult to separate. Reaction of CH2=CHBr with CF3OF gives 1-bromo1-fluoro-2-(trifluoromethoxy)ethane. 2-Bromo-2-chloro-1,1-difluoro-1-

(trifluoromethoxy)ethane is prepared by reaction of CF2=CHBr with CF3OCl. The IR (in some

cases of a mixture) and 19F NMR spectra are reported for all of these compounds. 

A number of hydrobromofluoro-ethers have been prepared by addition of alcohols 

(alkoxides) to bromofluoroethenes [30 and 31]. The preparation of 2-bromo-1,1,2-trifluoro-1-

35
ethoxyethane by this same route has been reported elsewhere [32]. 1-Bromo-1,1,2,2-tetrafluoro2-methoxyethane has been prepared by reaction of CXF2CBrF2 (X = halogen) with methoxide 

ion [33]. 

Reaction of formaldehyde and HF with 2-bromo-1,1-difluoroethene (CF2=CHBr) gives 

2-bromo-1,1,1-trifluoro-3-(2-bromo-3,3,3-trifluoropropoxy)propane, boiling point 167 °C) and 

bis(2-bromo-3,3,3-trifluoropropoxy)methane. Reaction of chloro-1,2-bis(trifluoromethoxy)-

ethene with bromine has been used to prepare 1,2-dibromo-chloro-1,2-bis(trifluoromethoxy)-

ethane, boiling point 94 to 95 °C. 

3. Bromofluoro-amines 

A number of fluorinated amines have been prepared by reactions of alkenes with 

bromobis(trifluoromethyl)amine (NBr(CF3)2) (Table 23) [34]. N,NBis(trifluoromethyl)bromodifluoromethanamine, boiling point 35.6 °C has been prepared by 

ultraviolet (UV)-induced decarbonylation of N,N-dimethylaminodifluoroacetyl bromide 

((CH3)2NCF2C(O)Br) [35] and by reaction of (difluoromethylene)(trifluoromethyl)amine (F3CN=CF2) with bromodifluoromethyl)triphenyl-phosphonium bromide ((C6H5)3(CF2Br)P+ Br-

) 

[36]. The latter synthesis also gives N,N-bis(trifluoromethyl)difluoromethanamine, boiling point 

7.8 °C. 

36
Table 23. Amines Prepared by Bromobis-(trifluoromethyl)amine Addition to Alkenes. 

CCOD 

ID 

Compound name Compound formula a Boiling 

point, °C 

919 N,N-bis(trifluoromethyl)-1-bromo-1,1,2,2-

tetrafluoroethan-2-amine 

N(CF3)2(CF2CF2Br) 60.9

1053 N,N-bis(trifluoromethyl)-2-bromo-2,2-

difluoroethanamine 

N(CF3)2(CH2CBrF2) 79.9

1200 2-bromo-1,2-difluoro-N,Nbis(trifluoromethyl)ethanamine N(CF3)2CHFCHBrF 76.4

1202 2-bromo-N,N-bis(trifluoromethyl)ethanamine N(CF3)2(CH2CH2Br) 85.6

1203 2-bromo-1,2,2-trifluoro-N,Nbis(trifluoromethyl)ethanamine N(CF3)2(CHFCF2Br) 62.4

1204 2-bromo-1,1,2-trifluoro-N,Nbis(trifluoromethyl)ethanamine N(CF3)2(CF2CHFBr) 74

1207 2-bromo-2-chloro-1,1,2-trifluoro-N,Nbis(trifluoromethyl)ethanamine N(CF3)2(CF2CFClBr) 93.5

1208 2-bromo-1,2-dichloro-1,2-difluoro-N,Nbis(trifluoromethyl)ethanamine N(CF3)2(CFClCFClBr) 125.6

1209 2-bromo-1,1,2,3,3,3-hexafluoro-N,Nbis(trifluoromethyl)propanamine N(CF3)2(CF2CFBrCF3) 82.2

a

At one atmosphere. 

C. SYNTHESES PERFORMED OR ATTEMPTED 

1. 2-Bromo-3,3,3-trifluoropropene, CH2=CBrCF3

The synthesis of 2-bromo-3,3,3-trifluoropropene (CH2=CBrCF3) was successful. 

Commercially available and relatively inexpensive 3,3,3-trifluoropropene (CF3CH=CH2) was 

brominated to produce the intermediate compound 1,2-dibromo-3,3,3-trifluoropropane 

(CF3CHBrCH2Br), which was subsequently dehydrohalogenated yielding the final product 2-

bromo-3,3,3-trifluoropropene. Bromination of 3,3,3-trifluoropropene was performed 

photochemically in the presence of carbon tetrachloride and under reflux conditions to yield 1,2-

dibromo-3,3,3-trifluoropropene. This compound was subsequently dehydrohalogenated using 

37
dry potassium hydroxide and reflux conditions. The product 2-bromo-3,3,3-trifluoropropene 

was isolated quantitatively following distillation. 

2. 1-Bromo-2-trifluoromethyl propene, ((CF3)2C=CHBr) 

Wittig reaction has been used for a long time as a generally useful method for the 

synthesis of alkenes from carbonyl compounds under mild conditions. Considering the 

commercial availability of starting material hexafluoroacetone (CF3)2C=O, it is a reasonable 

way to use Wittig reaction to synthesize 1-Bromo-2-trifluoromethyl propene (I).This reaction 

route consists of two steps. The first step is the synthesis of Bromomethyltriphenylphosphonium

Bromide. The second step involves generating the corresponding ylide and carrying out the 

Wittig reaction to generate the alkene. Though this effort did result in 1-bromo-2-

trifluoromethyl propene being identified by gas chromatography/mass spectroscopy a 

commercial source ultimately was located and the material acquired for testing. 

3. Fluorobromoalkyl-amines 

Several potential commercial sources for the synthesis the starting material, 

(CF3)2NBr, which would be used in subsequent synthesis of several of the bromofluoro-amines 

of interest were contacted. This starting material is reported to readily undergo insertion 

reactions with a variety of alkenes yielding compounds of the general structure 

(CF3)2NC2HxFyBr. The approach was abandoned following repeated unsuccessful attempts to 

obtain this starting material. Bromofluoroalky-amines were eventually acquired by an alternate 

synthetic method, Section III, D. 

D. COMMERCIAL AND ACADEMIC SOURCES 

To take advantage of a broad range of synthetic specialists and facilitate the acquisition 

of compounds for test and evaluation inquires were addressed to the former Soviet Union; Sigma 

Aldrich; Fluorochem Limited; PCR, Inc.; Oakwood Products, Inc.; Lancaster Synthesis; 

SynQuest Laboratories, Inc.; Durham Organics; Dr. Ed Kiskowski (Flura Corp.); P&M-1, LTD; 

Dr. Bill Banister (University of Massachusetts, Lowell); Dr. Jon Kremsky (Prime Organics); Dr. 

38
Jean’ne Shreeve, University of Idaho; Dr. William Allcock (University of Tenn.); and Dr. 

Lorrain Deck (Univ. of New Mexico). 

1. Compounds acquired 

The ten bromofluoro-alkenes and bromofluoro-amines acquired are listed in

and . Boiling points ranged from 40°C for 1-bromo-3,3,3-trifluoropropene to a high 

of 80°C for bis(trifluoromethyl)-2-bromo-2-fluoroethylamine. 

Table

24

Table 24. Brominated Tropodegradable Alkenes Acquired 

Table 25

CCOD 

ID 

Compound, Formula Boiling 

point (°C) 

707 1-Bromo-3,3,3-trifluoropropene, CF3CH=CHBr 40

1116 2-Bromo-3,3,4,4,4-pentafluorobutene, CF3CF2CBr=CH2 56

1358 2-Bromo-3,3,4,4,5,5,5-heptafluoropentene,

CF3CF2CF2CBr=CH2

78 

1359 2-Bromo-3-trifluoromethyl-3,4,4,4-tetrafluorobutene, 

CF3CF(CF3)CBr=CH2

78 

1360 2-Bromo-3-trifluoromethoxy-3,4,4,4-tetrafluorobutene, 

CF3CF(OCF3)CBr=CH2

75 

1391 1-Bromo-2-trifluoromethyl-3,3,3-trifluoropropene, 

(CF3)2C=CHBr 

63 

1413 1-Bromo-4,4,4,3,3-pentafluorobutene,

CF3CF2CH=CHBr 

58 

*Testing performed using premixed agent/air mixtures 

39
Table 25. Tropodegradable Bromofluoro-amines Acquired 

CCOD 

ID** 

Compound, Formula Boiling 

point 

°C 

1392 Bis(trifluoromethyl)-2-bromo-1,2,2-trifluoroethyl

amine, N(CF3)2(CHFCF2Br) 

72* 

1393 Bis(trifluoromethyl)-2-bromo-1,1,2-trifluoroethyl

amine, N(CF3)2(CF2CFHBr) 

72* 

1398 Bis(trifluoromethyl)-2-bromo-2-fluoroethylamine,

N(CF3)2(CH2CF2Br) 

80 

* As a 60/40 mixture of 1392 and 1393 

** NMERI Chemical Compound Options Database ID 

The source of each of the compounds acquired is listed in Table 26. 

Table 26. Compound Suppliers 

CCOD 

ID 

Compound, Formula Source 

707 1-Bromo-3,3,3-trifluoropropene, CF3CH=CHBr SynQuest

Laboratories 

1116 2-Bromo-3,3,4,4,4-pentafluorobutene, CF3CF2CBr=CH2 P&M-1, Ltd

1358 2-Bromo-3,3,4,4,5,5,5-heptafluoropentene, CF3CF2CF2CBr=CH2 P&M-1, Ltd

1359 2-Bromo-3-trifluoromethyl-3,4,4,4-tetrafluorobutene, 

CF3CF(CF3)CBr=CH2

P&M-1, Ltd 

1360 2-Bromo-3-trifluoromethoxy-3,4,4,4-tetrafluorobutene, 

CF3CF(OCF3)CBr=CH2

P&M-1, Ltd 

1391 1-Bromo-2-trifluoromethyl-3,3,3-trifluoropropene, 

(CF3)2C=CHBr 

SynQuest 

Laboratories 

1413 1-Bromo-4,4,4,3,3-pentafluorobutene, CF3CF2CH=CHBr P&M-1, Ltd

1392 Bis(trifluoromethyl)-2-bromo-1,2,2-trifluoroethyl amine,

N(CF3)2(CHFCF2Br) 

Univ. of Idaho 

1393 Bis(trifluoromethyl)-2-bromo-1,1,2-trifluoroethyl amine,

N(CF3)2(CF2CFHBr) 

Univ. of Idaho 

1398 Bis(trifluoromethyl)-2-bromo-2-fluoroethylamine,

N(CF3)2(CH2CF2Br) 

Univ. of Idaho 

40
E. CUP-BURNER TESTING 

While the basic cup-burner design employed at NMERI to characterize the flame 

extinguishments of test compounds has not changed the manner in which samples are introduced 

has undergone improvement. Illustrated below is the approach employed in gathering data prior 

to this project, Figure 1. The method introduces liquid or gaseous agents from a pressurized 

storage vessel situated on a computer interfaced standard balance into the air stream entering the 

base of the cup-burner. The base of the cup-burner is heated to ensure complete evaporation of 

liquids. Agent/air concentrations are automatically calculated based on input on weight loss 

rates and total air flow. 

While this method works well in principal occasionally the flow of gaseous as well as 

highly volatile liquid agents is not smooth due to evaporation in the needle valve assembly and 

the capillary tubing employed. Higher boiling liquid agents can also present a flow rate 

calculation problem when they fail to instantly evaporate o introduction into the base of the cupburner. Both of these problems can vary in severity depending on the precise conditions of the 

test. To eliminate errors and allow a more precise comparison of the flame extinguishments 

performance of agents tested the agent introduction method was modified. 

41
 Air Inlet 

(Regulated to 26 lb/in2 ) 

MixingChamber

Digital Thermometer 

Cup Burner Apparatus

0 10 

Metering Valve 

Fuel

Pressure Gage 

0 100

Pressure Gage 

0 

L/min

Heated Sand Bath

8-kg Scale (0.1 g)

 with RS-232 Output

Needle Valve

Data Acquisition Computer

Digital Flowmeter

Metering

 Valve

Glass Beads

Agent Fill Piping

175-ml Cylinder

Support

Stand 

Agent

 Flow

Septum

Figure 1. NMERI cup-burner utilizing mass loss flow rate characterization 

Illustrated below are the changes and improvements made to the agent introduction 

method, Figure 2. The principal change is the use of a pre-mixed and pre-analyzed agent/air 

reservoir. This change ensures uniformity in agent/air concentrations during flame 

extinguishment testing as well as sufficient sample for analytical determination of the agent 

concentration. In the current configuration a 10L Tedlar bag is employed. This allows several 

extinguishment determinations to be made from the same sample. The technique employed 

starts with an air concentration of approximately 5% (vol./vol.). Flame extinguishment for the 

compounds studied is very rapid (<<5 sec.) at this level. Following each successful 

extinguishment the bag of agent and air is diluted, mixed and retested. This process is repeated 

until the agent/air mixture no longer extinguishes the flame. 

42
Figure 2. NMERI cup-burner with premixed agent/air source. 

The twelve tropodegradable compounds acquired in this project were tested for their 

flame extinguishment performance using this technique. The extinguishment concentrations (% 

vol./vol.) observed are listed in Table 27 and Table 28. All agent air concentration data were 

determined by capillary gas chromatography employing three point calibration curves bracketing 

the air concentration ranges tested. Calibration standards were prepared from the neat liquid 

agent and room air as 0.5L or 1.0L samples. Compound purity, barometric pressure and ambient 

temperature corrections were employed in the preparation of all standards. 

43
Table 27. Cup-burner Flame Extinguishment and Application Temperature Limits 

Compound Formula Boiling

point 

(°C) 

Cupburner 

(%) 

Lowest 

temp for 

5% conc. 

1-Bromo-3,3,3-trifluoropropene CF3CH=CHBr 40 (3.5) -30 °C 

3-Bromo-3,3-difluoropropene CBrF2CH=CH2 42 4.5 -30 °C 

2-Bromo-3,3,3-trifluoropropene CF3CBr=CH2 34 2.6 -35 °C 

4-Bromo-3,3,4,4-tetrafluorobutene CF2BrCF2CH=CH2 54 3.5 -15 °C 

2-Bromo-3,3,4,4,4-

pentafluorobutene 

CF3CF2CBr=CH2 56 (3.8) -15 °C 

2-Bromo-3,3,4,4,5,5,5-

heptafluoropentene 

CF3CF2CF2CBr=CH

2

78 (3.7) -10 °C 

2-Bromo-3-trifluoromethyl3,4,4,4-tetrafluorobutene CF3CF(CF3)CBr=C

H2

78 (3.3) -10 °C 

2-Bromo-3-trifluoromethoxy3,4,4,4-tetrafluorobutene CF3CF(OCF3)CBr=

CH2

75 (3.8) -10 °C 

1-Bromo-2-trifluoromethyl-3,3,3-

trifluoropropene 

(CF3)2C=CHBr 63 (2.6) -15 °C 

1-Bromo-4,4,4,3,3-

pentafluorobutene 

CF3CF2CH=CHBr 58 (3.1) -15 °C 

Table 28. NMERI Cup-Burner Flame Extinguishment and Application Temperature Limits 

CCOD 

ID** 

Compound, Formula Boiling 

point 

°C 

Cupburner 

(%) 

Lowest 

temp for 

5% conc. 

1392 Bis(trifluoromethyl)-2-bromo-1,2,2-trifluoroethyl

amine, N(CF3)2(CHFCF2Br) 

72 2.4* -10

1393 Bis(trifluoromethyl)-2-bromo-1,1,2-trifluoroethyl

amine, N(CF3)2(CF2CFHBr) 

72 2.4* -10

1398 Bis(trifluoromethyl)-2-bromo-2-

fluoroethylamine, N(CF3)2(CH2CF2Br) 

80 2.4 -10

* Results of a 60/40 blend of CCOD’s 1392 and 1393 

** NMERI Chemical Compound Options Database ID 

44
SECTION IV. 

TECHNICAL PROBLEMS 

The acquisition of chemicals, most of whom have never been synthesized, is very costly 

and very time consuming. In order to minimize per compound costs a modification to cupburner test methods was developed and indicated in Task 3. This modification makes it possible 

to obtain an upper-bound value for the cup-burner extinguishment using as little as 2 grams of a 

test compound, in some cases, instead of 50 grams. This modification does not affect the utility 

of the resulting cup-burner value and in fact provides greater accuracy in air concentration 

measurements and actual test conditions. This modification was described earlier in greater 

detail in Section 4, Detailed Description of the Project. 

45
SECTION V. 

RECOMMENDATIONS 

This project has further developed the list of tropodegradable bromocarbons for which 

flame extinguishment performance is known. Recent data on the inhalation toxicity the 

bromofluoro-alkenes underscores the potential of these compounds. The boiling points of the 

current bromofluoro-alkenes which range down to 34 and in some cases as low as 25 °C may 

permit their use at application temperatures as low as –40°C depending on actual evaporation 

rates and low temperature fire suppression requirements. 

The identification of compounds with lower boiling points is highly likely and would 

potentially enhance the low temperature performance of this class of compounds in fire 

suppression applications. There remain several bromofluoro-alkene structures with the potential 

to have lower boiling points than that of 2-bromo-3,3,3-trifluoropropene. The acquisition and 

cup-burner testing of these compounds should be a priority. 

Limited toxicity testing is essential to progress in the area of compound selection. As has 

been stated in this report on several occasions actual toxicity test data on the bromofluoroalkenes, ethers, and amines of interest is very limited. Cost effective sources of testing have 

been identified and should be considered for future projects. 

46
SECTION VI. 

CONCLUSION 

The objective of the project is to develop new chemical compounds to replace Halon 

1301 for total flood fire extinguishment applications. Potential halon replacements must be 

highly efficient fire suppressants, have low environmental and toxicological impacts, have the 

same performance characteristics as Halon 1301, and be compatible with existing fire 

extinguishing equipment and aircraft materials. This research program includes syntheses of 

new compounds; laboratory analyses of fire suppression characteristics; analyses of 

environmental and toxicity parameters. This project builds on several previous DoD funded 

projects [37 and 38]. 

Past research work on tropodegradable bromocarbons had limited funding from the U.S. 

Air Force (USAF) and U.S. Navy (USN). Cup-burner flame extinguishment testing presented 

here and in previous reports as well as the recent acute inhalation toxicity testing data continue 

to underscore the potential of tropodegradable bromocarbons as to perform as Halon 1301 

replacements [2, 39]. This research project greatly expanded the list of tropodegradable 

bromocarbons whose flame extinguishment has been characterized and also provided estimations 

of compound environmental characteristics, evaluations of acute inhalation toxicity, physical 

properties, and boiling point limitations affecting agent air concentrations. 

In this project, bromofluoroalkenes were the primary focus of compound selection, 

acquisition and testing efforts due to their promising toxicity, flame suppression, short 

atmospheric lifetime, and acceptable physical properties. Data from the RTECS database as well 

as acute inhalation toxicity and subsequent AMES test data for several of the bromofluoro 

alkenes of interest here is very promising. Flame extinguishment testing of several bromofluoro 

alkenes have yielded cup-burner values comparable to those of halon 1301 and 1211. Finally, 

synthetic methods, in some cases, are expected to enable relatively low cost manufacture of 

selected bromofluoroalkenes and give hope to the potential for low cost industrial preparation of 

others. 

 

47
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48
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an Exploratory List of Chemicals to Initiate the Search for Halon Alternatives, NIST 

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16 Atkinson, R., “Estimations of OH Radical Rate Constants from H-Atom Abstraction from

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18. McMillen, D. F., and Golden, D. M., Annual Reviews of Physical Chemistry, Vol. 33, 

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49
21. Larsen, E. R., Ilgenfritz, E. M., and Ruh, R. P., “3,3-Difluoroallyl Esters,” USA, Patent 

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22. Seyferth, D., Simon, R. M., Sepelak, D. J., and Klein, H. A., “gem-Difluoroallyllithium:

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23. Seyferth, D., Simon, R. M., Sepelak, D. J., and Klein, H. A., “gem-(Difluroallyl)lithium: 

Preparation by Lithium-Halogen Exchange and Utilization in Organosilicon and Organic 

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24. Birchall, J. M., Fields, R., Haszeldine, R. N., and McLean, R. J., “Cyclopropane 

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25. Tarrant, P., and Tandon, J. P., “The Peroxide-Initiated Addition of Some

Polyfluorochloro- and Polyfluorobromoalkanes to Some Hydrocarbon Olefins,” Journal 

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26. Muramatsu, H., and Tarrant, P., “The Addition Reaction of Bromotrichloromethane to 

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27. Ueda, K., and Muraki, T., “β-Bromotetrafluoropropionic Acid,” Japan, Patent Number 68 

29129, 13 December 1968. Assigned to Toyo Rayon Company, Ltd. 

28. Santini, G., Le Blanc, M., and Riess, J. G., “19F NMR Chemical Shifts of n-F-Alkyl 

Compounds,” Journal of Fluorine Chemistry, Vol. 10, pp. 363-373, 1977. 

29. Johri, K. K., and DesMarteau, D. D., “Comparison of the Reactivity of CF3OX (X = Cl, 

F) with Some Simple Alkenes,” Journal of Organic Chemistry, Vol. 48, pp. 242-250, 

1983. 

30. Demiel, A., “Addition of Alcohols to Fluorinated Ethylenes,” Journal of Organic 

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31. Jiang, X.-K., Ji, G.-Z., and Shi, Y. Q., “Observation of a Competitive Path in the 

Nucleophilic Addition of Fluoroolefins: The Bromophilic Reaction of the Adduct 

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32. Haszeldine, R. N., “The Reactions of Metallic Salts of Acids with Halogens. Part III. 

Some Reactions of Salts of Fluorohalogenoacetates and of Perfluoro-acids,” Journal of 

the Chemical Society, pp. 4259-4268, 1952. 

50
33. Carle, W. P., and Ezzell, B. R., “Halofluoroalkyl Ethers,” U.S. Patent 4,423,249, 27 

December 1973. Assigned to Dow Chemical Company (Chemical Abstracts, 102755a, 

Vol. 100, 1984). 

34. Haszeldine, R. N., and Tipping, A. E., “Perfluoroalkyl Derivatives of Nitrogen. Part 

XVII. The Reaction of N-Bromobistrifluoromethylamine with Olefins,” Journal of the 

Chemical Society, pp. 6141-6145, 1965. 

35. Fukaya, H., Ave, T., Eiji, H., Hayakawa, Y, and Baba, H., “Nitrogen-Containing 

Perfluoroalkyl Bromides and Their Manufacture,” Japan, Patent Number 06,122,658, 6 

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1994). 

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37. Heinonen, E. W., Kaizerman, J. A., Lifke, J. L., Mather, J. D., Moore, T. A., and 

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51
APPENDIX A 

GLOSSARY 

Acute Toxicity—The effect of a single high-level exposure, as would occur during accidental 

release. 

Alcohol—Compounds containing one or more hydroxyl (-OH) groups attached to a nonaromatic 

hydrocarbon. Examples are methanol (CH3OH), ethanol (C2H5OH), and ethylene glycol 

[C2H2(OH)2]. 

Alkene—Also designated “olefin.” A compound containing doubly bonded carbon atoms 

(excluding aromatic compounds) as in ethene (H2C=CH2) and propene (H2C=CHCH3). 

Alkoxy—A group of the type -OR, where R is an aliphatic hydrocarbon radical or a substituted 

aliphatic radical. Examples are methoxy (-OCH3) and ethoxy (-OC2H5). 

Alkyl—An aliphatic substituent. Examples are methyl (-CH3), ethyl (-CH2CH3 or -C2H5), npropyl (-CH2CH2CH3 or -C3H7), i-propyl (-CH(CH3)2), n-butyl (-CH2CH2CH2CH3 or -C4H9), 

t-butyl (-C(CH3)3). 

Ames Assay—A preliminary test for mutagenicity on bacteria - designed primarily as a rapid 

screen for possible carcinogens. Both false positives and false negatives are common, so the test 

is never used on its own. 

Aromatic—Cyclic molecules or fused cyclic molecules containing formally alternating single 

and double bonds with delocalized π electrons. The most common simple aromatic compound is 

benzene. 

Carcinogenic or Carcinogenicity—A term applied to substances causing cancer. 

Cardiac—Having to do with the heart. 

Cardiac Sensitization—An effect in which the heart is rendered more sensitive to the action of

adrenaline and similar drugs. This can result in sudden heart failure. 

Ether—Compound containing the group C-O-C as in dimethyl ether, CH3-O-CH3. 

Genotoxicity—The ability of a material to cause damage to genes or chromosomes. 

Genotoxicity studies provide an early screen for possible cancer-inducing activity.

Haloalkane—Saturated halocarbons containing only carbon, halogen, and, in some cases, 

hydrogen atoms. 

52
53

Haloalkoxy—A group of the type -OR, where R is an aliphatic hydrocarbon group or a 

substituted aliphatic group containing one or more halogen atoms. Examples are chloromethoxy 

(-OCH2Cl) and 2-bromoethoxy (-CH2CH2Br). 

Haloalkyl—An aliphatic substituent containing one or more halogen atoms. Examples are 

tribromomethyl (-CBr3) and 2-chloroethyl (-CH2CH2Cl). 

Halocarbon—A compound of carbon and one or more halogen atoms with or without hydrogen. 

Halogenated—Containing halogen atoms or having halogen atoms added to the structure. 

Hydrochlorofluorocarbon—An aliphatic compound containing only hydrogen, chlorine, 

fluorine, and carbon. An example is HCFC-123, CHCl2CF3. 

Hydrofluorocarbon—An aliphatic compound containing only hydrogen, fluorine, and carbon. 

An example is HFC-134a, CH2FCF3. 

In vitro—Studies or methods using cultured cells or organisms. 

In vivo—Studies or methods which involve the use of whole animals. 

LC50—Lethal concentration 50%; a measure of acute toxicity. The concentration of a substance 

in air expected to kill half of a group of test animals exposed for a specified period. 

LD50—Lethal dosage 50%; a measure of acute toxicity. The dose of a substance expected to kill 

half of a group of test animals exposed for a specified period. 

LOAEL—Lowest Observed Adverse Effect Level. The minimum dose or concentration at 

which a sign of harm is observed. 

Mouse Micronucleus Assay—An in vivo test for clastogens using a mouse. 

NOAEL—No Observed Adverse Effect Level. The maximum dose or concentration at which 

no signs of harm are observed. 

Perfluorocarbon—An aliphatic compound containing only fluorine and carbon. An example is 

FC-218 (sometimes called PFC-218), CF3CF2CF3. 

Quantitative Structure-Analysis Relationships—Correlations between a biological activity 

and physical, chemical, and structural composition of a compound. QSARs are used to 

determine the toxicity of an unknown substance based on the measured toxicity of similar 

chemicals.

Tropodegradable—An adjective applied to compounds that are rapidly removed from the 

earth’s troposphere by such mechanisms as photolysis, reaction with hydroxyl free radical, 

rainout, and physical removal.