EPA/600/R-09/037 | April 2009 | www. epa.gov/athens



# Composition and Behavior of Fuel Ethanol

Ecosystems Research Division, Athens, GA 30605 National Exposure Research Laboratory Office of Research and DevelopmentEPA/600/R-09/037 April 2009



# Composition and Behavior of Fuel Ethanol by

James W. Weaver (a) 

### Sheldon A. Skaggs (b)



### David L. Spidle (a) 

### Guthrie C. Stone (c)

(a) Ecosystems Research Division, National Exposur e Research Laboratory, Office of Research and Development, United States Environmental Protection Agency, Athens, Georgia (b) Sheldon Skaggs, Inc, Athens, Georgia (c) The University of Georgia, Athens Georgia



### Ecosystems Research Division National Exposure Research Laboratory

Office of Research and Development United States Environmental Protection Agency Athens, Georgia 30605

U.S. Environmental Protection Agency

Office of Research and Development Washington, DC 20460

## Notice The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research de scribed here. It has been subjected to the Agency = s peer and administrative review and ha s been approved for publication as an EPA document. Mention of tr ade names or commercial pr oducts does not constitute endorsement or recommendation for use. The information provided in this paper is not intended for determining compliance with state or federal regulations fo r air quality, gasoline composition or other similar purposes. For these purposes, information should be obt ained from the appropr iate local, state and federal regulatory agencies, the Clean Air Ac t, the United States Code, the Code of Federal Regulations, the Federal Re gister and other sources.

2

## Abstract Ethanol usage in the United States has incr eased due in part to the elimination of methyl tert-butyl ether from the fuel suppl y and to the mandates of Congress. Two samples, one each from a wet mill and a dry mill ethanol plant, were obtained before denaturing. Each of these samples contained mostly ethanol, but also low concentrations of water, methanol, and higher molecular wei ght alcohols (up to five carbons). The wet mill sample also contained ethyl acetate and an ether, 1,1-diethoxyethan e. The allowable denaturants for fuel ethanol are similar to ga soline. Since the denaturants are immiscible with water, the ability of the denatured fuel ethanol to absorb water is limited. Experiments with E95 and E85 showed that these both began to phase separate when about 15% water was added to the E95 or E 85. The gasoline was re leased gradually as water was added to the fuel. For E95, there is a smaller amount of gasoline in the fuel (2% to 5%) so less gasoline can be released. The change s in volume when water and ethanol or water and E85 are mixed displaye d a deficit of 3% at maximum. The byproducts of fuel ethanol production are less soluble, sorb more, diffuse less readily, and are less volatile than etha nol. It’s likely, however, that the increased ethanol concentration in water will increase the so lubility of the byproducts, as it does the petroleum hydrocarbons The production byproduct s compose less than 1% of the mass of the fuel. Releases of fuel ethanol will be dominated by the ethanol.

3

## Foreword The National Exposure Research Laboratory = s Ecosystems Research Division (ERD) in Athens, Georgia, conducts research on orga nic and inorganic chemicals, greenhouse gas biogeochemical cycles, and la nd use perturbations that cr eate direct and indirect, chemical and non-chemical stresses, expos ures, and potential risks to humans and ecosystems. ERD develops, tests, applie s and provides technical support for exposure and ecosystem response models used for a ssessing and managing risks to humans and ecosystems, within a watershed / regional context. The Regulatory Support Branch (RSB) conducts problem-driven and applied research, develops technology tools, and provides t echnical support to customer Program and Regional Offices, States, Municipalities, and Tribes. Models are distributed and supported via the EPA Center for Exposur e Assessment Modeling (CEAM) and through access to Internet tools ( www.epa.gov/athens/onsite). Fuel composition provides the starting point for evaluation of releases to the environment. For ethanol gasolines, the co mposition of the fuel differs from typical gasoline by the addition of large amounts of ethanol and the presence of fermentation byproducts. Physically, the fuel can be s ubject to phase separa tion upon contact with water. This report provides basic information on usage of ethanol in U.S. gasoline, fuel ethanol production methods, analytical methods for fuel and water samples, fuel ethanol composition and properties, and phase behavi or. This information forms the starting point for evaluation of potential enviro nmental impacts and ecosystem and human exposures.

Eric J. Weber, Ph.D. Acting Director Ecosystems Research Division Athens, Georgia

4

## Oil Spill Report Series

A series of research reports is planned to present data and models for oil spill planning and response. To date, these include: 1. Oil Composition James W. Weaver, Sheldon A. Skaggs, David C. Spidle, Guthrie Stone, 2009, Composition of Fuel Ethanol, Unite d States Environmental Protection Agency, Washington, D.C., EPA/600/R-09/037.

Zhendi Wang, B.P. Hollebone, M. Fingas, B. Fieldhouse, L. Sigouin, M. Landriault, P. Smith, J. Noonan, and G. Thouin, 2003, Characteristics of Spilled Oils, Fuels, and Petroleum Products: 1. Composition a nd Properties of Selected Oils, United States Environmental Protection Agency, National Exposure Research Laboratory, EPA/600/R-03/072. 2. Dispersants George Sorial, Subhashini Chandrasekar, James W. Weaver, 2004, Characteristics of Spilled Oils, Fuels, and Petroleum Products : 2a. Dispersant Effectiveness Data for a Suite of Environmental Conditions – The Effects of Temperature, Volatilization, and Energy, United Stat es Environmental Protection Agency, National Exposure Research Laboratory, EPA/600/R-04/119.

3. Simulation Models James W. Weaver, 2004, Character istics of Spilled Oils, Fuel s, and Petroleum Products: 3a. Simulation of Oil Spills and Disper sants Under Conditions of Uncertainty, United States Environmental Protecti on Agency, National Exposure Research Laboratory, EPA/600/R-04/120.

As more reports are added to the series, they may be found on EPA’s web site at: http://www.epa.gov/athens/publications

.

5

## Leaking Underground Storage Tank Assessment Report Series

A series of research reports is planned to present data and models for leaking underground storage tank risk assessments. To date these include: 1. Gasoline Composition James W. Weaver, Sheldon A. Skaggs, David C. Spidle, Guthrie Stone, 2009, Composition of Fuel Ethanol, Unite d States Environmental Protection Agency, Washington, D.C., EPA/600/R-09/037. James W. Weaver, Linda R. Exum, Lour des M. Prieto, 2008, Gasoline Composition Regulations Affecting LUST Sites, United States Environmental Protection Agency, Washington, D.C., EPA/600/R-08/xxx. Weaver, James W., Lewis Jordan and Daniel B. Hall, 2005, Predic ted Ground Water, Soil and Soil Gas Impacts from US Gasolines , 2004: First Analysis of the Autumnal Data, United States Environmental Protection Agency, Washington, D.C., EPA/600/R-05/032.

2. Simulation Models Gorokhovski, Vikenti M. and James W. W eaver, 2007, A Catalog of Ground Water Flow Solutions for Plume Diving Calculations , United States Environmental Protection Agency, Washington, D.C. Weaver, James W., 2004, On-line Tools for A ssessing Petroleum Releases, United States Environmental Protection Agency, Washington, D.C ., EPA 600/R-04/101. 3. Model Background and Evaluation Weaver, James W. and C. S. Sosik, 2007, Asse ssment of Modeling Reports for Petroleum Release and Brownfields Sites, United States Environmental Protection Agency, Washington, D.C ., EPA 600/R-07/101.

As more reports are added to the series, they may be found on EPA = s web site at: http://www.epa.gov/athens/publications.

6

## Contents

Notice

............................................................................................................................... ... 2 Abstract ............................................................................................................................... 3 Foreword ............................................................................................................................. 4 Oil Spill Report Series ........................................................................................................ 5 Leaking Underground Storage Tank Assessment Report Series ........................................ 6 Contents .............................................................................................................................. 7 Figures

............................................................................................................................... .. 8 Tables

............................................................................................................................... . 10 Terminology ...................................................................................................................... 11 Introduction ....................................................................................................................... 12 Background and Literature Review .................................................................................. 14 Regulatory History of Gasoline .................................................................................... 14 Ethanol Use in Gasoline ................................................................................................ 14 Gasoline Production in the United States ..................................................................... 16 Fuel Ethanol.................................................................................................................. 21 Byproducts in Fuel Ethanol .......................................................................................... 22 Analytical Methods ....................................................................................................... 24 Phase Separation and Co-solvency ............................................................................... 24 Fuel Ethanol Analyses ...................................................................................................... 29 Phase Separation ............................................................................................................... 35 Fuel Ethanol Component Properties ................................................................................. 39 Solubility ....................................................................................................................... 39 Octanol-Water Partition Coefficient ............................................................................. 41 Water and Air Phase Diffusion Coefficients ................................................................ 41 Vapor Pressure .............................................................................................................. 41 Henry’s Constant .......................................................................................................... 42 Property Variation with Temperature ........................................................................... 42 Discussion and Conclusions ............................................................................................. 46 References ......................................................................................................................... 48 Appendix A Analytical Methods ..................................................................................... 52 Fuel Ethanol Analysis ................................................................................................... 52 Phase Separation ........................................................................................................... 53 Appendix B Detected and tentatively identi fied chemicals from an ethanol plant in Minnesota [10]. ................................................................................................................. 55 Appendix C Ethanol and Water Mixtures ........................................................................ 57 Appendix D Comparison of results from the EPI Suite TM calculator and SPARC for K ow for 5 o C and 25 o C. ............................................................................................................ 59 Appendix E SPARC Property Results for 5 o C to 45 o C ................................................. 61

7

## Figures Figure 1 Renewable and biofuel mandates from the Energy Policy Act (EPAct) of 2005 and the Energy Independence and Security Act (EISA) of 2007. .................................... 15 Figure 2 DOE gasoline production and importati on data. Prior to the Clean Air Act Amendments, there was no distin ction between conven tional and reformulated gasoline. The proportion of conventional gasoline (2/3) has remained roughly constant over the period 1995 to 2007. ......................................................................................................... 17 Figure 3 Production of reformulated gaso line with ether and alcohol, conventional gasoline with alcohol and total ga soline production on a weekly basis. .......................... 18 Figure 4 Benzene and ethanol content in conventional gasoline collected by Northop Grumman in 2007. ............................................................................................................ 20 Figure 5 Benzene and ethanol content in reformulated gasoline collected by Northop Grumman in 2007. ............................................................................................................ 20 Figure 6 Methanol-Water-Hydrocarbon phase diagram. ................................................. 25 Figure 7 Estimated benzene solubility using the co-solvency relationship developed by Heerman and Powers [19]. The hypothetical mi xtures consisted of blendstock containing 1 vol % benzene mixed with ethanol containing 2% of a denaturant that itself contained 1% benzene. Curves are plotted for the average parameters from Heerman and Powers [19] and their extreme parameter sets gi ving the lowest and highest peak benzene concentrations. .................................................................................................................. 28 Figure 8 Wet mill sample chromatogram. Retention times are shown in Error! Reference source not found.. .............................................................................................................. 30 Figure 9 Dry mill sample chromatogram. Retention times are shown in Table 1. ......... 31 Figure 10 QA blank -- showi ng internal standard (1, 3-Dibromo-2-propanol with retention time of 17.089 minut es) and alcohol matrix (retention time of 2.192 and 2.326 minutes). ............................................................................................................................ 31 Figure 11 Unbranched alcohols: Methanol CH 4 O (top) and Ethanol C 2 H 6 O (center) and 1-Propanol C 3 H 8 O (bottom) molecules. ........................................................................... 32 Figure 12 Branched chain al cohols: Isobutyl alcohol C 4 H 10 O (top), 2-methyl 1-butanol C 5 H 12 O (center) and 3-methyl 1-butanol C 5 H 12 O (bottom) molecules. .......................... 33 Figure 13 Ethyl acetate C 4 H 8 O 2 molecule. ....................................................................... 34 Figure 14 Ethers: The di-ether 1,1-diethoxyethane C 6 H 14 O 2 (top) and MTBE C 6 H 12 O (bottom) molecules. .......................................................................................................... 34 Figure 15 Release of gasoline from E95 (top) and E85 (bottom) at varying amounts of water added. The gasoline is normalized to the nominal amount of gasoline in the E95 (5% of 7 ml) or E85 (15% of 20 ml). The wa ter is normalized to the volume of E95 (7 ml) or E85 (20 mL). .......................................................................................................... 37

8Figure 16 Volume changes as water is added to a sample of E85. All the volumes are normalized to the volume of E85 (20 ml). ........................................................................ 38 Figure 17 Total volume reduction dur ing addition of water to ethanol. ......................... 38 Figure 18 Benzene C 6 H 6 molecule. ................................................................................. 40 Figure 19 Estimates from the EPA EPI Suite calculator, SPARC at 5 o C and 25 o C plotted against experimental results reported with EPI Suite results. ............................... 59 Figure 20 Example of variation in SPARC results given an assumed variability (error) of one-half log unit. The left hand graph show s results on a log-log sc ale. The right hand graph shows the same variation on a linear scale. ............................................................ 60 Figure 21 Solubility of the alcohols found in the wet and dry mill samples. Ethanol and methanol do not appear because their solubility is infinite. .............................................. 61 Figure 22 Solubility of ethyl acetate and 1,1-diethoxy ethane, compounds found in the wet mill sample. Solubilities of bezene and MTBE are plotted for comparison. ............ 61 Figure 23 Properties (Henry's Law coeffici ent, vapor pressure, air phase diffusion coefficient, octanol/water part ition coefficient) for methanol and ethanol estimated by the SPARC calculator. ............................................................................................................ 62 Figure 24 Properties (Henry's Law coeffici ent, vapor pressure, air phase diffusion coefficient, octanol/water pa rtition coefficient) for 1-propanol and isobutyl alcohol estimated by the SPARC calculator. ................................................................................. 63 Figure 25 Properties (Henry's Law coeffici ent, vapor pressure, air phase diffusion coefficient, octanol/water partition coeffici ent) for 2-methyl 1-butane and 3-methyl 1- butane estimated by the SPARC calculator. ..................................................................... 64 Figure 26 Properties (Henry's Law coeffici ent, vapor pressure, air phase diffusion coefficient, octanol/water partition coeffici ent) for ethyl acetate estimated by the SPARC calculator. .......................................................................................................................... 65 Figure 27 Properties (Henry's Law coeffi cient, vapor pressure , air phase diffusion coefficient, octanol/water pa rtition coefficient) for 1,1-diethoxyethane estimated by the SPARC calculator. ............................................................................................................ 66 Figure 28 Properties (Henry's Law coeffi cient, vapor pressure , air phase diffusion coefficient, octanol/water partition coefficient) for benzene and methyl tert -butyl ether (MTBE) estimated by the SPARC calculator. .................................................................. 67

9

## Tables

Table 1 Compounds identified by GC-MS in two samples of fuel ethanol. Concentrations were determined by re tention time analysis using GC-FID. ................... 30 Table 2 Solubility, Henry's Constant, Va por Pressure, Air Phase Diffusion Coefficient and Octanol-Water Partition Coefficient estimated by the SPARC calculator for fuel ethanol components, benzene and MTBE at 15 C. ........................................................... 43 Table 3 SPARC estimated properties at 15 o C ranked from lowest to highest. .............. 44

10

## Terminology

Following ASTM D 4806 – 08a Standard Speci fication for Denatured Feul Ethanol for Blending with Gasolines for Use as Au tomotive Spark-Ignition Engine Fuel.

Denaturant -- a material added to fuel etha nol to make it unsuitable for beverage use, but not for unsuitable for automotive use. Fuel Ethanol -- ethanol with impurities comm on to its production including water but not denaturants. Denatured Fuel Ethanol – fuel ethanol made unfit for beverage use by the addition of denaturants. Higher Molecular Weight Alcohols – aliphatic alcohols of general formula C n H 2n+1 OH with n from 3 to 8. Following the Code of Federal Regulations ( 40 CFR) Part 80 – Regulation of Fuels and Fuel Additives: Reformulated Gasoline (RFG) is any gasoline whose formulation has been certifited under 40 CFR § 80.40 and which meets each of the standards and requirements prescribed under 40 CFR § 80.41. From 1995 until 2006, RFG was required to contain 2 % by weight oxygencontaining compounds (“oxygenates”) Conventional Gasoline (CG ) is any gasoline which has not been certified under 40 CFR § 80.40. Oxygenated Gasoline (OG) is any gasoline which contains a measurable amount of oxygenate.

11

## Introduction

Gasoline composition has changed because of engine requirements, clean-air and energy-policy legislation, and EPA rule-mak ing. Although ethanol has been in use in motor gasolines for many years, its usage began to increase after 2000 due to concerns over methyl tert -butyl ether (MTBE) pollution of gr ound waters and the resulting state bans of MTBE. Later Congress passed legi slation that both removed the oxygenate requirement for reformulated gasoline and requ ired increased use of renewable fuels. Thus since 2006 there has been a large incr ease in the use of et hanol in the U.S. The object of this report is the comp osition and behavior of fuel ethanol, denatured fuel ethanol, and consumer blends (particularly the 15% gasoline-containing E85). Because of Bureau of Alcohol and Tobacco regulations, producers of fuel ethanol generally do not distribute th eir product in a non-d enatured form. Further, analysis of denatured fuel ethanol is complicated by the addition of the numerous constituents of the typical denaturant, namely gasoline. An objec tive of this research was to obtain samples of non-denatured fuel ethanol. One sample each of the two main production methods – wet milling and dry milling -- was obtained for analysis. The quantity of these samples was limited so analyses were performed on s lightly less limited quantities of denatured fuel ethanol (E95) and the easily obtained consumer product E85. These samples were used to investigate composition of fuel ethanol. Literature on alcohol production for fuel and beverage s was used as a guide for the possible constituents of these products. Gas chromatography (GC) coupled with mass spectroscopy (MS) was used for unambiguous identification of the constituents. Subsequent analyses using GC with a flame ionization detector (FID) and Karl Fischer

12titration was used to quantify the concentrations of the constituents. Properties of the identified components of fuel ethanol were then estimated using the SPARC chemical property estimator. SPARC was us ed so that temperature de pendence of properties could be explored. Phase separation of E95 and E85 was studied because when spilled or released to the environment, in most cases these fuels w ill encounter either surface water in the form of flowing streams, creeks, or rivers; ponds, lakes or estuaries; or soil moisture and ground water. Response to incidents may vary if the fuel forms a separate phase or mixes

with water. Since the fuels have a certai n water tolerance, phase separation may depend on the composition of the fuel and the nature of the release to water. Ethanol and water

are known not to mix in direct proportion to their volumes. This effect might change the behavior of the fuel/water system during rel eases. Simple experiments were devised to determine the volume changes in various ethanol/ gasoline blends. The report is intended to provide a brief overview of the composition and properties of ethanol fuels and contains the following sections describing four topics: composition, chemical properties, phase separation and volume changes.

13

## Background and Literature Review The background and literature review is di vided into seven sections, each of which bears on the objectives of the report. The topics are

• Regulatory History of Gasoline,

• Ethanol Use in Gasoline,

• Gasoline Production in the United States,

• Fuel Ethanol,

• Byproducts in Fuel Ethanol,

• Analytical Methods, and

• Phase Separation and Co-solvency.



### Regulatory History of Gasoline

The Clean Air Act Amendments of 1990 introduced a number of different requirements that had a major impact on gasoline composition throughout the entire United States from their implementation in 1992 and 1995 until the present. See Weaver et al. [1] for more detail. The most impor tant factors for understanding the current usage of ethanol were the total ban on lead in ga soline, requirements for conventional gasoline (CG), reformulated gasoline (RFG), and oxygenated gasoline (OG). Both RFG and OG programs required usage of oxygenated gasoline additives, and for the first years of the programs, the most commonly used oxygenate was MTBE.



### Ethanol Use in Gasoline Because of subsurface water quality concer ns from releases of fuels containing MTBE, states began in 2000 to ban MTBE and, in some cases, other ethers and alcohols

14as fuel additives. Since they were actions taken by state legislatur es, they did not affect federal requirements for oxygenate usage. Th e bans had the effect of causing ethanol usage as a fuel oxygenate to increase in th e U.S. The oxygen mandate for reformulated gasoline was removed by the Energy Policy Ac t of 2005. The act al so required usage of renewable fuels, causing another increase in ethanol usage. The Energy Independence and Security Act (EISA) of 2007 increased the mandated amounts of biofuels for 2008 through 2012 and extended the period of require d use of biofuels to 2022. The EISA also required targeted amounts of advanced and ce llulosic biofuels for the periods 2009 to 2022 and 2010 to 2022, respectively ( Figure 1 ).

2006 2008 2010 2012 2014 2016 2018 2020 2022 

## Year 0 10 20 30 40Billion Gallons Renewable Fuel Mandates EISA 2007 Renewable Fuel EISA 2007 Conventional Biofuel EISA 2007 Conventional and Cellulosic Biofuel EPAct 2005 Renewable Fuel

Cellulosic

Conventional (starch based) Other Advanced

Figure 1 Renewable and biofuel mandates from the Energy Policy Act (EPAct) of 2005 and the Energy Independence and Securi ty Act (EISA) of 2007.

15

### Gasoline Production in the United States

Gasoline production data compiled by the Department of Energy’s Energy Information Agency (EIA) documents the production and importa tion of conventional and reformulated gasoline [2]. These da ta show that production of RFG began in September 1994 shortly before the imp lementation of the RFG program ( Figure 2 ). RFG replaced part of the total production of ga soline in the U.S. The remainder became conventional gasoline simply by definition (see 40 CFR §80.2). Production of both types of gasoline tended to increase, although RFG production increased faster than conventional gasoline production. Even so, conventional gasoline accounts for roughly two thirds of U.S. gasoline, a proportion that has been consistent since the beginning of the RFG/CG designation. EIA began differen tiating RFG containing et her, alcohol or no oxygenate in 2004 ( Figure 3 ). By this time most of the MTBE bans were in place so alcohol use in RFG was highest. The use of MTBE was slowly declining until the oxygenate mandate was removed by the Ener gy Policy Act of 2005 (EPAct 2005). In mid 2006 MTBE was abruptly remo ved from the fuel supply ( Figure 3 ) and the amount

of RFG made with ether decr eased to a negligible amount , while the amount of RFG made with alcohol abruptly increased. The EPAct 2005 legislation also required increased use of biofuels. Conventional ga soline showed increasi ng amounts of alcohol, especially after mid 2007. In 2007 the Ener gy Independence and Security Act mandated

increased levels of biofuel usage through 2022. As of Ma rch, 2009, EIA data show that 75% of the total gasoline produced in the U.S. contained alcohol. 1

1 For the week ending March 6, 2009, there were 8539 thousand barrels produced per day of finished motor gasoline. Of this there were 2896 thousand barrels produced per day of reformulated gasoline

16198219841986198819901992199419961998200020022004200620082010

Date 0 2000 4000 6000 8000 10000Thousand Barrels PerDay Total Production

Conventional

Reformulated

Figure 2 DOE gasoline production and importation data. Prior to the Clean Air Act Amendments, there was no distinction between conventional a nd reformulated gasoline. The proportion of conventional gasoline (2/3) has remained roughly cons tant over the period 1995 to 2007.

containing alcohol and 3549 thousand barrels produced per day of conventional gasoline containing alcohol.

172004200520062007200820092010

Date 0 2000 4000 6000 8000 10000Thousand Barrels perDay Total Production

Conventional and Reformulated with Alcohol

Reformulated with Alcohol

Reformulated with ether

Figure 3 Production of reformulated gasoline with ether and alcohol, conventional gasoline with alcohol and total gasoline production on a weekly basis.

Petroleum product surveys are conducted annually by Northrop Grumman [3]. Samples are collected from service stations and analyzed for selected compositional and physical properties. The benzene and ethanol data presented below were determined by ASTM methods [3]. These data show the variability of ethanol content within the

conventional and reformulated classes from cities representing the continental United

States. The benzene data were included b ecause it is an important gasoline component and is subject to specific regul ation by the Clean Air Act.

18For the summer sampling of 2007, conventional gasoline ( Figure 4 ) contained varying amounts of ethanol with two domina nt levels: about 10% and, with fewer samples, none. The samples with about 10% ethanol represent E10 and illustrate the observed variability for summer 2007. Outliers contained as much as 14.4% ethanol. Both premium (defined here as octane numbe rs (ON) greater than 90) and regular had ethanol contents throughout th e range from 0 to 11%. Benzene levels ranged to 3.6%

which is due to the benzene levels in conventional gasoline being set from 1990 producer/importer baselines [1] The summer 2007 reformulated gasoline ( Figure 5 )

showed also showed two dominant ethanol levels: around 10% and just under 6%.. Regular and premium gasoline showed no disc ernable patterns, but were represented throughout the data range. Compared to c onventional gasoline, benzene levels were lower in reformulated gasoline due to clean air act requirements. Most samples showed benzene levels below 1% by volume.

19

### Conventional Gasoline

0 0.5

1 1.5

2 2.5

3 3.5

4

0 2 4 6 81 0 1 2 1 4 1 6 Ethanol (vol %)Benzene (vol %) CG < 90 ON CG > 90 ON

Figure 4 Benzene and ethanol co ntent in conventional gasoline co llected by Northop Grumman in 2007. 

### Reformulated Gasoline

0 0.5

1 1.5

2 2.5

3 3.5

4

0 2 4 6 8 1 0 1 2 1 4 1 6 Ethanol (vol %)Benzene (vol %) RFG < 90 ON RFG > 90 ON

Figure 5 Benzene and ethanol content in reformu lated gasoline collected by Northop Grumman in 2007.

20

### Fuel Ethanol Fuel ethanol is produced by several methods. The most common is the dry mill process that accounts for 75% of current pr oduction. Dry mill plants typically produce ethanol as the primary product with animal f eed (called Dried Distiller’s Grains with Solubles, DDGS) and carbon dioxide as co-products. In dry milling the entire corn kernel is ground and used as the feed stock for ethanol production [4, 5]. In wet milling, the corn is first separated into its components: starch, fiber, gluten and germ [4]. These plants produce ethanol as one of several food industry products including corn oil, corn syrup, and corn sugar. After fermentation th e alcohol is distilled to 190 proof to reduce the water content. Afterward, molecular sieve technology is used to remove the remaining water. For use as a fuel, ethanol is made unfit fo r drinking by addition of a denaturant. ASTM [6] gives requirements for fuel ethanol and accepta ble denaturants for use in automobile engines. Fuel ethanol is permitted by ASTM to contain 1.76% to 5.0% denaturant. Beginning on January 1, 2009, the 2008 Food, Conservation, and Energy Act allows a full ethanol production credit onl y so long as the denatu rant content is no more than 2% [7]. Because of measurement difficulties, the Internal Revenue Service is temporarily allowing credits as long as th e denaturant(s) do not exceed 2.5% of the volume of the fuel ethanol [8]. The allowable denaturants are:

• natural gasoline,

• gasoline components, or

• unleaded gasoline.

.

21The ethanol content, after de naturing, is to be a minimu m of 92.1% at the time of blending with gasoline and the water content of the fuel ethanol is to be less than 1%. ASTM also specifies prohibited denaturants:

• hydrocarbons with an end boiling point above 225 o C,

• methanol not meeting ASTM D1152,

• pyrroles,

• turpentine,

• ketones, and

• tars. These substances are said to have potentia lly extreme adverse effects on fuel stability, automotive engines, and fuel systems. Sin ce the typical boiling range of gasoline is 90

o C to 200 o C [9], the first prohibited denaturant list ed above indicates that denaturants for fuel ethanol are intended to be very much like gasoline.



### Byproducts in Fuel Ethanol

Fermentation of corn starch produces ethanol and other compounds. Although ethanol is the dominant alcohol produced, a variety of others have been documented [10]. Air emissions from a beer brewer/d ry-mill ethanol plant were monitored and a number of hydrocarbons were identified. Clas ses of compounds incl uded tearing agents (lacrimators), respiratory irritants and odorants. Specific examples included formaldehyde, acetaldehyde, furfural, 2- Furancarboxaldeyde, acrolein, benzene, methanol, ethanol, glycerol, styrene, lactic acid and acetic acid [11]. The complete list of compounds is given in Appendix B, although most of these have not been reported as

constituents of fuel ethanol itself. Th e main byproducts of ethanol production are isopropyl and isobutyl alcohols, but also include methyl , amyl, iso-amyl, n-propyl,

22glycerol (1,2,3-propanetriol), higher alcohols, ethers, acet ic aldehyde and acids. The presence of pentoses leads to production of furfural (furan-2- carbaldehyde), which degrades rubber or elastomeric seals 2 . Production of the byproducts can reduce ethanol production by 10%. Because of competiti on among microorganisms, the longer that fermentation continues, the more equilibri um shifts toward the higher alcohols, aldehydes, acids or methane [11]. For comparison purposes, the following literature on beverage alcohol production was reviewed as a related pr oduction activity might show in sight into issues of fuel ethanol. In production of beverages [13] found acetal s (i.e., 1-1 diethoxyethane) occurring in small quantities. The occurren ce of acetals began to be significant after 4 hours of fermentation and is related to higher ac idity related to infect ions of acid-forming bacteria. Esters are formed from organic ac ids and predominantly ethanol. In the first hours of fermentation ethyl and methyl esters of acetic acid were produced. In later stages of fermentation esters of higher al cohols appeared (isoamyl acetate, isobytyl acetate, and ethyl hexanate)

. Other compounds produced include 2-propanol, acroleine (in the form of acroleine diethy lacetal), acetic aldehyde [13] . Production of fermentation byproducts is important to beverage producers or consumers because volatile esters impart flav ors [13, 14], contaminants can be present in illegally produced alcohol [ 15], and reduction in some byproducts is needed for foodgrade alcohol [16]. Fan and Qian found a la rge number of flavor imparting compounds in increased concentration in five-year ol d Chinese Liquor which was aged in a clay vessel [14]. In a study of contaminants of illegally-produced dri nking alcohol, analysis

2 Corrosion of steel is attributed to the formation of ethanol/water molecular structures as well as the amount of water itself [12].

23was performed for the ethanol, isopropanol, ace tone, methanol, ethylene glycol and lead contents [15]. A later summary of studies indicated analysis fo r ethanol, methanol, 1- propanol, iso-butanol and isoa myl alcohol were commonly an alyzed in evaluation of these liquors [17]. 

### Analytical Methods

There are common aspects of analytical methods for alcohol analyses. ASTM specifies a long nonspecific narr ow-bore capillary column and direct injection to a gas chromatograph (GC) with a flame ionization det ector (FID) [18]. Others have used direct injection to a CG-FID [19] using a wax column [13] or non-polar fused silica column [20]. Trace level analyses of ethanol , MTBE and other alcohols and ethers have been conducted with solid phase micro ex traction (SPME) using a DVB/Carbozen/PDMS fiber, a GC equipped with a fused silica co lumn and mass selective detector [14, 21]. Solid phase extraction was used to concentr ate impurities in Brazilian ethanol prior to GC-MS identification [22].



### Phase Separation and Co-solvency

Although water and gasoline are mutually immiscible, a small amount of each is soluble in the other. Typical water contents of non-ethanol gasolines are on the order of 0.01%. As the ethanol content increases, th e amount of water that can be accommodated

in the fuel increases. There is a limit, however, to this tolerance beyond which the fuel separates into a predominantly water phase and a predominantly gasoline phase. Phase

24partitioning data that represent this phenom ena are commonly represented on tri-linear phase diagrams, where a boundary separates the single- from the two-phase regions. An example phase diagram is shown in Figure 6 . The solid curve on the diagram represents the boundary between a one-phase region and a two-phase region. At any point on the diagram, the amount of water, ethanol and hydr ocarbon can be read from the three axes. If a mixture contained 85% ethanol, 15% hydrocarbon and no water, its location on the diagram is the beginning point of the dashed ar row. The mixture would exist as a single phase. By increasing the water content, the mi xture moves in the direction of the arrow. Once the phase boundary is reached, then the mixture breaks into two phases: a predominantly aqueous/alcohol phase and an predominantly oil phase. Note, however, each of the three components is presen t to some degree in the two phases.

0 0.2 0.4 0.6 0.8 1 % Hyd r oca r bon 1

0.8

0.6

0.4

0.2

0 %

E t h a n o l

1 0.8 0.6 0.4 0.2 0

%

W

a t e r

Two Phase One Phase

Figure 6 Methanol-Water-Hydrocarbon phase diagram.

For gasoline fuels, the tri-linear diagram has some conceptual utility, but there are many more than three species present. Regardless, the approach allows for a visual

25representation of the various combinations of water, ethanol, and “gasoline” that co-exist in solution in either a single or dual phase. Letcher et al. [23] m easured phase separation in gasoline-water-alcohol systems and f ound somewhat suppressed phase separation at higher temperatures. Phase separation was al so suppressed in the order: methanol, 1- butanol, ethanol and 1-propanol. K. Y. Lee [24] compared published phase equilibrium data against predicted phase boundaries in th ree phase water/solvent and BTEX systems and also in systems with a mixed solvent. These showed reasonable agreement for

ethanol and methanol as solvents. Naka yama [25] described phase separation in methanol-gasolines as potentially including three layers: water, emulsified watergasoline and gasoline. Higher molecular weig ht alcohols were shown by H. K. Lee and coworkers [26] to have suppressed phase se paration at low temperatures in methanolsurrogate gasoline blends. French and Malone [27] presented an exte nsive review of the effects of ethanol on gasoline, including in creased vapor pressure at certain ethanol concentrations, materials compatibility and the influence of temperature on phase separation. More detail on pot ential impacts from subsurf ace releases from ethanol fuels can be found in Rixey and co-workers [28]. In multicomponent systems, ethanol has the ability to increase the apparent solubility of a partly miscible compound. For the case of the ethanol gasoline, there might be sufficient ethanol present to increa se the concentration of gasoline components in water. Heermann and Powers [19] determin ed the equilibrium phase concentrations of benzene, toluene, ethylbenzen e and xylenes (BTEX) for va rious amounts of ethanol in solution. Their purpose was to determin e the degree of co-solvency caused by the alcohol and to identify modeling approaches for predicting equilibrium concentrations.

26They concluded that the best fit consis ted of a piecewise model that had a linear relationship for low ethanol contents (approximately 25% or less) and a log-linear relationship for higher ethanol contents. Data were fit to a surrogate gasoline consisting of eight compounds and then used to pred ict BTEX concentrations for commercial gasolines. Estimated aqueous concentrations of benzene calculated from the method developed by Heerman and Powers are shown in Figure 7 . The aqueous concentration of benzene from a gasoline mixture depends on th e amount of benzene pr esent in the fuel and the co-solvency due to the presence of ethanol in water 3 . As the amount of ethanol increases, so does the co-solve ncy, but this effect is balanced by the decline in benzenecontaining blendstock used in formulating hi gher ethanol content fu els. A hypothetical mixture of blendstock containing 1% benzene and denatured fuel ethanol is plotted in Figure 7 . The fuel ethanol was assumed to be denatured with 2% gasoline which itself contained 1% benzene. At ethanol contents below a bout 25 volume %, there is no increase in benzene solubility for this mixt ure. The aqueous benzene concentration peaks at about 85% ethanol. Higher ethanol content causes a decline in the benzene

concentration due to the reduction in benzene content of the fuel. The plot shows the estimated concentration for the average paramete r set and the extreme values of the fitted parameters that give the lowe st and highest peak concentration. The latter are included because Heerman and Powers gave 95% confidence limits on their fitted parameters. The

estimate of benzene concentration from these considerations is 645 +/- 85 mg/L at a

3 When phase separation of an ethanol blend gasoline occurs the bulk of the ethanol partitions to the water phase [23]. thus, assuming that most of the alcohol initially present in the gasoline phase moves to the water phase is reasonable. This behavior differs from mixtures where 1-propanol or 1-butanol serve as the alcohol phase. For these the bulk of th e alcohol stays with the gasoline phase.

27volume fraction of 87.5% denatured alcohol. This value is about 20 times the aqueous phase concentration of benzene when no ethanol is present (i.e., 33.7 mg/L).



### Estimated Benzene Concentration

0 100 200 300 400 500 600 700 800

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Ethanol Volume FractionEstimated Benzene Concentration(mg/L) Average Case 3 Case 6

Figure 7 Estimated benzene solubility using the co -solvency relationship de veloped by Heerman and Powers [19]. The hypothetical mixtures consiste d of blendstock containi ng 1 vol % benzene mixed with ethanol containing 2% of a denaturant that it self contained 1% benzene. Curves are plotted for the average parameters from Heerman and Powers [ 19] and their extreme parameter sets giving the lowest and highest peak benzene concentrations.

28

## Fuel Ethanol Analyses Two samples of corn-based, fuel etha nol (non-denatured) were obtained from their manufacturers and analyzed according to the following procedure. There was one sample each from a wet mill and dry mill process. First, gas chromatography/mass spectroscopy (GC/MS) was used to identify the unknown constituents of the samples, followed by quantitation of the concentration us ing GC/FID, and Karl Fischer titration of the samples for their water content. The deta ils of the analytical methods used in this study are presented in Appendix A. Analysis of the wet and dry mill samples showed that the fuel ethanol samples included one-, two- and thre e-carbon unbranched alcohols: methanol, ethanol and propanol ( Table 1 and Figure 11 ); four- and five-carbon bran ched alcohols: isobutyl alcohol and the two isomers of pentanol (also known as am yl alcohol, see Figure 12 ): 2- methyl 1-butanol (active amyl alcohol) and 3-methyl, 1-butanol (isoamyl alcohol). The wet mill sample contained two additional compounds both known byproducts of fermentation: ethyl acetate ( Figure 13 ) and, the di-ether, 1,1-diethoxyethane ( Figure 14 ). Although higher molecular weight alcohol s were found in each sample, the bulk of the samples, 97.30% of the wet mill and 96.60% of the dry mill sample were composed of ethanol. The three to five carbon alcohols composed 0.26% and 0.19% of the samples, respectively. Subtracting the total weight percents of the quantitated compounds and water from 1.00, gives the amount of unidentified material as 1.28% and 3.00% respectively.

29Table 1 Compounds identified by GC-MS in two sa mples of fuel ethanol. Concentrations were determined by retention time analysis using GC-FID.

Concentration (wt. %) Name Formula CAS. Number Retention Time (min) Wet Mill Sample Dry Mill Sample

Water (1) H 2 O 7732-18-15 n.a. 0.65 0.08 Methanol CH 4 O 67-55-1 2.191 0.07 0.06 Ethanol (2) C 2 H 6 O 64-17-5 2.324 97.3 96.60 1-Propanol C 3 H 8 O 71-23-8 2.673 0.03 0.08 Isobutyl Alcohol C 4 H 10 O 78-83-1 3.186 0.10 0.08

2-Methyl 1-

Butanol C 5 H 12 O 137-32-6 5.147 0.06 0.01 3-Methyl 1-

Butanol C 5 H 12 O 123-51-3 5.033 0.21 0.02 Ethyl Acetate C 4 H 8 O 2 141-78-6 3.077 0.02 -- 1,1- Diethoxyethane C 6 H 14 O 2 105-57-7 4.958 0.28 -- (1) Determined by Karl Fischer titration (2) Determined by remainder of other compounds

Figure 8 Wet mill sample chromatogram. Retention times are shown in Error! Reference source not found. .

30Figure 9 Dry mill sample chromatogr am. Retention times are shown in Table 1 .

Figure 10 QA blank -- showing internal standard (1, 3-Dibromo-2-propanol with retention time of 17.089 minutes) and alcoho l matrix (retention time of 2.192 and 2.326 minutes).

31Figure 11 Unbranched alcohols: Methanol CH 4 O (top) and Ethanol C 2 H 6 O (center) and 1-Propanol C 3 H 8 O (bottom) molecules.

32Figure 12 Branched chain alcohols: Isobutyl alcohol C 4 H 10 O (top), 2-methyl 1-butanol C 5 H 12 O (center) and 3-methyl 1-butanol C 5 H 12 O (bottom) molecules.

33Figure 13 Ethyl acetate C 4 H 8 O 2 molecule.

Figure 14 Ethers: The di -ether 1,1-diethoxyethane C 6 H 14 O 2 (top) and MTBE C 6 H 12 O (bottom) molecules.

34

## Phase Separation

Phase separation results for an E95 and an E85 sample are shown in Figure 15 . A

limited amount of E95 was available for test ing so a simplified procedure was used (See Appendix A). The results show that phase se paration occurs with addition of water to

each of these fuels. Each fuel accommodated a certain amount of water. In both cases this was approximately 15% to 20% of the fu el volume. When the water added to the fuel increased beyond this level, gasoline was released from the fuel. The release of gasoline, however, occurred ove r an interval of water addi tions that continued until approximately 45% of the E95 volume and 50% of the E85 volume. At higher amounts of water added, the maximum amount of gaso line was released. Since the amount of gasoline in the E95 and E85 was unknown the re leased volumes might not have reached the presumed total (i.e, the normalized gasoline levels are below 1.0). Particularly for the E95, the volume of gasoline was very small ( 0.21 mL or less), so that the measurement accuracy is fairly low. For higher levels of water added to E 85, the gasoline volume was reduced from its maximum. This might have occurred because of the small volumes of gasoline released, the presence of an emulsified la yer, and volume changes when E85 and water are combined. When ethanol is added to gaso line, the volume of the mixture is slightly greater than the sum of the volumes. When water is added to etha nol the volume of the

mixture is less than the sum of the volumes. This phenomena occurs because some of the polar ethanol molecules are accommodated within the structure that forms from the polar water molecules [29]. The volume reduction fo r alcohol-water mixtures is on the order

35of 5%. (See Appendix C for a discussion of the physical chemistry of these ethanolwater volume effects.) Figure 16 shows the volume changes observed when water was added to E85. Here the average values from the four experiments plotted in Figure 15 were used to determine the average volume of the aqueous phase (solid line), the average volume of the gasoline phase and the tota l volume (dot-dash line). These are compared against the total volume added during the experiments (uppe r dashed line). The figure shows that the total volume resulting from the addition of water to E85 is less than the sum of the water and E85 combined (upper dashed line). The deficit of volume was about 3% for these experiments. Figure 17 shows experimental and theore tical results for the volume

of mixtures of water and ethanol. The theo retical calculation was made from the theory presented in Appendix C a nd the data published by Pe č ar and Dole č ek [30]. The maximum reduction found in both the experime nt and theoretical calculation of about 3.5% roughly corresponds to the reduction in volume observed for mixtures of E85 and water ( Figure 16 ).

360 0.4 0.8 1.2 1.6 2 

## Normalized Water Addition 0 0.2 0.4 0.6 0.8

1Normalized Gasoline Released

E85 and E95 E85 - 1 E85 - 2 E85 - 3 E85 - 4 0 0.4 0.8 1.2 1.6 2 

## Normalized Water Addition 0 0.2 0.4 0.6 0.8

1Normalized Gasoline Released

E85 and E95 E95

Figure 15 Release of gasoline from E95 (top) and E85 (bottom) at varying amounts of water added. The gasoline is normalized to the nominal amount of gasoline in the E95 (5% of 7 ml) or E85 (15% of 20 ml). The water is normalized to th e volume of E95 (7 ml) or E85 (20 mL).

370 0

. 4 0

. 8 1

. 2 1

. 6 No 2 r malized Wate r A dded 0.8 1.2 1.6

2 2.4 2.8 3.2Normalized Volume Volume Effects Cumulative Volume Added Average Aqueous and Fuel Phases Average Aqueous Phase

Figure 16 Volume changes as water is added to a samp le of E85. All the volumes are normalized to the volume of E85 (20 ml).

0 0.4 0.8 1.2 1.6 2 Fraction of Water Volume Added to Ethanol Volume 0 1 2 3 4Percent Volume Reduction

Ethanol-Water Volume Mixtures Theory 25 C at 0.1 MPa Experiment 1 Experiment 2

Figure 17 Total volume reduction duri ng addition of water to ethanol.

38

## Fuel Ethanol Component Properties

The properties of the chemicals found in the fuel ethanol samples were estimated using the SPARC calculator [31] that is available for use via the Internet. 4 These estimates were used, because all parameters were not found in the literature for all chemicals and, more importantl y, measured values are not av ailable for all temperatures of interest (5 o C to 45 o C). For comparison purposes, properties of benzene and methyl

tert -butyl ether (MTBE) were also estimat ed from SPARC. Appendix D contains a comparison of SPARC-generated and EPI Suite TM -generated properties, along with an estimate of error in SPARC properties.

Table 2 shows the results for 15 o C from SPARC for solubility, Henry’s constant, vapor pressure, the air phase diffusion coefficient, the water phase diffusion coefficient, and the octanol-water partiti on coefficient. The compounds are ordered first by number of oxygen atoms (one or two) and then by number of carbon atoms. Table 3 shows the

same 15 o C results ordered by parameter value.



### Solubility Solubility can be viewed as a dir ect measurement of hydrophobicity or the tendency of water to exclude a substance from solution. The solubility is the maximum concentration which an aqueous solution will tolerate before the onset of phase separation [32]. Ethanol and methanol are infinitely so luble in water. Any amount of ethanol or

methanol can be dissolved in water without forming a separate phase. All of the other

4 http://ibmlc2.chem.uga.edu/sparc/

39compounds found in the samples have finite so lubility. Alcohols, though, have a greater affinity for water than either benzene, MTBE or the 1,1-diethoxyethane. Benzene is nonpolar (observe the symmetric structure with no oxygen in Figure 18 ) so it’s solubility is the lowest of this group. Figure 21 and Figure 22 show the variation in solubility from 5

o C to 45 o C. The actual water phase concentrations resulting from par titioning of these compounds or other constituents of gaso line are significantly lower than these

solubilities. In effect the concentration obtained from a mi xture depends on the solubility of a component and the amount present in the mixture [ 33]. Consequently the solubilities presented in Table 2 , Table 3 , Figure 21 and Figure 22 are much greater than the

concentrations that would be observe d in water contacted with gasoline.

Figure 18 Benzene C 6 H 6 molecule.

40

### Octanol-Water Partition Coefficient The octanol-water partition coefficient, K ow, is a measure of the tendency for a chemical to preferentially partition from water to organic matter [34]. This coefficient is generally inversely related to solubility and provides information similar to the compound’s solubility—albeit in an inverse sense. The most soluble compounds have the least degree of partitioning to octanol. The SPARC results show almost a direct reversal from solubility. In the environm ent the octanol-water partition coefficient corresponds to the tendency to partition to soil organic matter or animal tissues.



### Water and Air Phase Diffusion Coefficients The diffusion coefficients for water and air are measures of the ability of the molecule to diffuse through intermolecular co llisions [34]. Generally, the air phase diffusion coefficients are roughly four orders of magnitude higher than the water phase

diffusion coefficients. Obvious ly, diffusion through air occurs much more readily that diffusion in water (similarly diffusion coefficien ts in solids are again much lower than those for water). Generally smaller molecules diffuse more readily than larger molecules

and this trend is evident in the SPARC results for both water and air.



### Vapor Pressure

Vapor pressure is a measure of the maximum possible concentration of a compound in the gas phase at a given temperatur e. This quantity re presents equilibrium partitioning of an organic chemical betw een the gaseous phase and compound itself

4142 (liquid or solid). It provides informati on on the attractive forces among the compound’s

molecules in the conde nsed phase [35]. Table 3 shows that at 15 o C the vapor pressures of the alcohols were inversely related to th eir molecular weight. Therefore methanol had the highest vapor pressure and 3-methyl 1-butanol the lowest.



### Henry’s Constant The Henry’s Constant measures equilibrium partitioning between air and water.

Table 3 shows that for the alcohols the Henr y’s Constants increase with increasing molecular weight. The ordering is generally inverse to that for the solubility, as the higher the water solubility the less tendency to partition to the air.



### Property Variation with Temperature

The SPARC calculator provides prediction of temperature-dependence of all its estimated property values. The variation over the range of 5 o C to 45 o C of the properties discussed here are pres ented in Appendix E.Table 2 Solubility, Henry's Constant, Vapor Pressure, Air Phase Diffusion Coefficient and Octanol-Water Partition Coefficientestimated by theSPARC calculator for fuel ethanol components, benzene and MTBE at 15 C.SPARC(1)estimated properties at 15 CSolubilityHenry’sConstantVaporPressureAir DiffusionCoefficientWaterDiffusionCoefficientOctanol-WaterPartitionCoefficientNameFormula(mg/L)(atmm3/mol)(torr)(cm2/s)(cm2/s)(dimensionless)MethanolCH4OInfinite3.4 x 10-6770.1501.3 x 10-50.24EthanolC2H6OInfinite5.4 x 10-6460.1101.0 x 10-50.741-PropanolC3H8O2.2 x 1057.3 x 10-6150.0948.7 x 10-63.31Isobutyl AlcoholC4H10O9.3 x 1049.0 x 10-670.0817.7 x 10-68.512-Methyl 1-ButanolC5H12O2.8 x 1041.1 x 10-530.0727.0 x 10-623.403-Methyl 1-ButanolC5H12O1.9 x 1041.2 x 10-520.0716.9 x 10-633.11BenzeneC6H61.0 x 1037.0 x 10-3690.0858.7 x 10-6147.91MTBEC6H12O1.8 x 1041.2 x 10-31900.0746.5 x 10-634.67Ethyl AcetateC4H8O24.3 x 1041.5 x 10-4540.0807.4 x 10-67.081,1-DiethoxyethaneC6H14O22.1 x 1041.8 x 10-4240.0625.8 x 10-634.67(1)SPARC estimates were generated from May 2008 release w4.2.1405-s4.2.1408,http://ibmlc2.chem.uga.edu/sparc/on 8/30/2008 and 8/31/200843Table 3 SPARC estimated properties at 15 o C ranked from lowest to highest. Solubility Octanol-Water Partition Coefficient Water Diffusion Coefficient g/L (dimensionless) cm 2 /s

name value name value name value

Benzene 1.0x 10 3 Methanol 0.24 1,1-Diethoxyethane 5.8 x 10 -6

MTBE 1.8 x 10 3 Ethanol 0.74 MTBE 6.5 x 10 -6

3-methyl 1-butanol 1.9 x 10 4 1-Propanol 3.31 3-methyl 1-butanol 6.9 x 10 -6

1,1-Diethoxyethane 2.1 x 10 4 Ethyl Acetate 7.08 2-methyl 1-butanol 7.0 x 10 -6

2-methyl 1-butanol 2.8 x 10 4 Isobutyl Alcohol 8.51 Ethyl acetate 7.4 x 10 -6

Ethyl acetate 4.3 x 10 4 2-Methyl 1-Butanol 23.40 Isobutyl alcohol 7.7 x 10 -6

Isobutyl alcohol 9.3 x 10 4 3-Methyl 1-Butanol 33.11 Benzene 8.7 x 10 -6

1-Propanol 2.2 x 10 5 1,1-Diethoxyethane 34.67 1-Propanol 8.7 x 10 -6

Ethanol Infinite MTBE 34.67 Ethanol 1.0 x 10 -5

Methanol infinite Benzene 147.91 Methanol 1.3 x 10 -5

4445 Table 3 (continued) SPARC estimated properties at 15 o C ranked from lowest to highest. Henry’s Constant Vapor Pressu re Air Diffusion Coefficient atm m 3 /mol torr cm 2 /s

name value Name value Name value

Methanol 3.4 x 10 -6 3-Methyl 1-Butanol 2 1,1-Diethoxyethane 0.062

Ethanol 5.4 x 10 -6 2-Methyl 1-Butanol 3 3-Methyl 1-Butanol 0.071 1-Propanol 7.3 x 10 -6 Isobutyl Alcohol 7 2-Methyl 1-Butanol 0.072 Isobutyl Alcohol 9.0 x 10 -6 1-Propanol 15 MTBE 0.074 2-methyl 1-Butanol 1.1 x 10 -5 1,1-Diethoxyethane 24 Ethyl Acetate 0.080 3-methyl 1-Butanol 1.2 x 10 -5 Ethanol 46 Isobutyl Alcohol 0.081 Ethyl Acetate 1.5 x 10 -4 Ethyl Acetate 54 Benzene 0.085 1,1-Diethoxyethane 1.8 x 10 -4 Benzene 69 1-Propanol 0.094

MTBE 1.2 x 10 -3 Methanol 77 Ethanol 0.110 Benzene 7.0 x 10 -3 MTBE 190 Methanol 0.150

## Discussion and Conclusions

Ethanol usage in the United States has incr eased due in part to the elimination of methyl tert-butyl ether from the fuel supply and to the mandates of Congress. Required

amounts of ethanol in fuel with increase the total through the y ear 2022. Current data show that 75% of U.S. produced gasoline contains ethanol. For the year 2007, the amounts in conventional gasoline ranged from none to 10.5%, with outliers at higher concentration. Premium gasolin e showed two maximums one near 6% and the other at about 10%. Two samples of non-denatured fu el grade ethanol, one each from a wet mill and a dry mill ethanol plant, were obtained before denaturing. Each of these samples contained mostly ethanol, but also low con centrations of water, methanol, and higher molecular weight alcohols (up to five carbons). The wet mill sample also contained ethyl acetate and an ether, 1,1-diethoxyethane. These two compounds might have been present due to the difference in production method, as wet milling is intended to produce a wide range of products from the components of corn.

The allowable denaturants for fuel etha nol are similar to gasoline. Unleaded gasoline, gasoline range hydrocar bons, natural gasoline or conde nsate can be used for this purpose. Since pure ethanol, the primary constitue nt of fuel ethanol is miscible in water, a large amount of water can be accommodated in fuel ethanol. Since the denaturants are immiscible with water, the abil ity of the denatured fuel ethanol to absorb water is limited. Experiments with E95 and E85 showed that these both began to phase separate when about 15% water was added to the E95 or E 85. The gasoline was re leased gradually as water was added to the fuel. Because about 50% water was needed for complete phase

46separation of the E95 and E85, phase sepa ration effects in flowing water can be estimated: If the flow in the receiving water body is 50% or greater than the release rate of the E95 or E85 phase separa tion is a likelihood. In these cases an “oil” slick composed of gasoline should be expected. For E95, there is a smaller am ount of gasoline in the fuel (2% to 5%) and the slick would be less massi ve than for the same spill of E85. The changes in volume when water and ethanol or water and E85 are mixed displayed a deficit of 3% at maximum. For example, a fuel spill that caused a release to a creek would increase the flow volume by its volum e less 3%. This phenomena for is unlikely to be environmentally significant. The byproducts of fuel ethanol produc tion are less soluble, sorb more, diffuse less readily, and are less volatile than ethanol. It’s likely, however, that the increased

ethanol concentration in water will increase the solubility of the byproducts, as it does the petroleum hydrocarbons. The byproducts compos e less than 1% of the mass of the fuel so releases of fuel ethanol will be dominated by the ethanol. Increased solubility of petroleum hydrocarbons is possible when the et hanol fraction is greater than about 20%. The solubility of benzene could increase by a factor of 20 due to the presence of the

ethanol.

47

## References

1. Weaver, J.W., L.R. Exum, and L.M. Prieto, Historical Impacts of Federal Regulation on Gasoline Composition 1990 – 2007. Environmental Forensics, 2008. 2. U.S. Department of Energy. Petroleum Refining & Processing, from the Petroleum Navigator . 2009 [cited 2009 March 15]; Available from: http://www.eia.doe.gov/

. 3. Dickson, S.L., Motor Gasolines, Summer 2003 NGMS-233 PPS 2004/1 . 2004, Northrop Grumman Mission Systems: Bartlesville, OK. 4. Bothast, R.J. and M.A. Schlicher, Biotechnological Processes for Conversion of Corn into Ethanol. Applied Microbiology and Biotechnology, 2005. 67 : p. 19-25. 5. Sánchez, Ó.J. and C.A. Cardona, Trends in biotechnologi cal production of fuel ethanol from different feedstocks Bioresource Technology, 2007. 99 (1-3): p. 5270-5295. 6. ASTM International, Standard Specification for Automotive Spark-Ignition Engine Fuel D 4814-09 . 2009, ASTM Internationa l: West Conshohocken, PA. 7. United States of America, Food, Conservation, and Energy Act of 2008 Public Law 110-123 . 2008. 8. U.S. Internal Revenue Service, Calculation of Volume of Alcohol for Fuel Credits; Denaturants, Notice 2009-06 , 2009. 9. Gary, J.H. and G.E. Handwerk, Petroleum Refining, Technology and Economics

. 4th ed. 2001, New York: Marcel Dekker, Inc. 441. 10. Anonymous, Public health assessment gopher st ate ethanol, City of St. Paul , in Report Under Cooperative Agreement with the Agency for Toxic Substances and Disease Registry . 2003, Minnesota Department of Health: St. Paul, Minnesota. 11. Patzek, T., A statistical analysis of the theore ctical yield of ethanol from corn starch. Natural Resources Reseach, 2006. 15 (3): p. 205-212. 12. Yahagi, Y. and Y. Mizutani, Corrosive wear of steel in gasoline-ethanol-water mixtures. Wear, 1984. 97 : p. 17 - 25. 13. Klosowski, G. and B. Czuprynski, Kinetics of acetals and esters formation during alcoholic fermentation of various starchy raw materials with application of yeasts Saccharomyces cerevisiae. Journal of Food Engineering, 2006. 72 : p. 242-246. 14. Fan, W. and M. Qian, Headspace solid phase mi croextraction and gas chromatography - olfactometry diluti on analysis of young and aged Chinese "Yanghe Daqu" liquors. Journal of Agricultural and Food Chemistry, 2005. 53 : p. 7931-7938. 15. Holstege, C., J. Ferguson, C. Wolf, A. Baer, and A. Poklis, Analysis of moonshine for contaminants. Journal of Toxicology - Clinical T oxicology, 2004. 42 (5): p. 597-601. 16. van Leeuwen, H., R. Wood, and J. Koziel, Method and system for purifying ethanol, Patent 20070284310 2007: United States.

4817. Lachenmeier, D.W., Rapid quality control of spir it drinks and beer using multivariate data analysis of Fourier transform infrared spectra. Food Chemistry, 2007. 101 (2): p. 825-832. 18. ASTM International, Standard Test Method for Determ ination of Ethanol Content of Denatured Fuel Ethanol by Gas Chromatography D5501-04 . 2004, ASTM International: West Conshohocken, PA. 19. Heermann, S.E. and S.E. Powers, Modeling the partitioning of BTEX in waterreformulated gasoline systems containing ethanol. Journal of Contaminant Hydrology, 1998. 34 : p. 315 - 341. 20. Rahman, M.A., M. Asadullah, M.S. Rahman, M.N. Nabi, and M.A.K. Azad, Extraction of gasohol grade ethanol from aqueous solution using gasoline as solvent. Bangladesh Journal of Scientif ic and Industrial Research 2007. 42 (3): p. 287 - 298. 21. Cassada, D.A., Y. Zhang, D.D. Snow, and R.F. Spalding, Trace analysis of ethanol, MTBE, and related oxygenate co mpounds in water using solid-phase microextraction and gas chro matograhpy/mass spectrometry. Analytical Chemistry, 2000. 72 : p. 4654 - 4658. 22. Vilar, R., R. da Silva, P. Schossler, R. Veses, C. Piatnicki, D. Samios, and E. Caramao, Preliminary characterization of anhy drous ethanol used in Brazil as automotive fuel. Journal of Chromatography A, 2003. 985 : p. 367-373. 23. Letcher, T.M., S.W. Heyward, and B. Shuttleworth, Ternary phase diagrams for gasoline-water-alcohol mixtures. Fuel, 1986. 65 : p. 891 - 894. 24. Lee, K.Y., Phase partitioning modeling of ethanol, isopropanol, and methanol with BTEX compounds in water. Environmental Pollution, 2008. 154 : p. 320 - 329. 25. Nakayama, M., Water tolerability of methanol-g asoline blends (phase separation and SI engine performances). SAE Technical Paper Series. 852200 : p. 185 - 191. 26. Lee, H.K., D.O. Shah, and N.D. Brinkman, Enhancing low-temperature phase stability of a 50/50 methanol/hydrocarbon blend. SAE Technical Paper Series, 1988. 881680 : p. 1 -8. 27. French, R. and P. Malone, Phase equilibria of ethanol fuel blends. Fluid Phase Equilibria, 2005. 228-229 : p. 27 - 40. 28. Rixey, W.G., X.H. He, and B.P. Stafford, The Impact of Gasohol and Fuel-Grade Ethanol on BTX and Other Hydrocarbons in Ground Water: Effect on Concentrations Near a Source, API So il and Groundwater Technical Task Force No. 23 . 2005, American Petroleum Institute: Washington, DC. 29. Pinho, S.P. and E.A. Macedo, Experimental measurement and of modeling KBr solubility in water, methanol, ethanol, and its binary mixed solvents at different temperatures. Journal of Chemcial Thermodymanics, 2002. 34 : p. 337 - 360. 30. Pecar, D. and V. Dolecek, Volumetric properties of ethanol-water mixtures under high temperature and pressures. Fluid Phase Equilibria, 2005. 230 : p. 36 - 44. 31. Karickhoff, S.W., V.K. Mc Daniel, C. Melton, A.N. Ve llino, D.E. Nute, and L.A. Carriera, Predicting chemical reactivity by computer. Environmental Toxicology and Chemistry, 1991. 10 : p. 1405-1416.

4932. Mackay, D., Solubility in Water , in Handbook of Property Estimation Methods for Chemicals, Environmental and Health Sciences , R.S. Boethling and D. Mackay, Editors. 2000, Lewis Pulishers: Boca Raton. p. 125-139. 33. Cline, P.V., J.J. Delfino, and P.S.C. Rao, Partitioning of aromatic constituents into water from gasoline and ot her complex solvent mixtures. Environmental Science and Technology, 1991. 25 : p. 914-920. 34. Gustafson, J.B., J.G. Tell, and D. Orem, Selection of Representative TPH Fractions Base on Fate and Transport Considerations . Total Petroleum Hydrocarbon Criteria Working Grou p Series. Vol. 3. 1997, Amherst, Massachusetts: Amherst Scie ntific Publishers. 102. 35. Schwarzenbach, R.P., P.M. Gschwend, and D.M. Imboden, Environmental Organic Chemistry . Second ed. 2003, Hoboken, New Je rsey: Wiley-Interscience. 36. Harris, D.C., Quantitative Chemical Analysis . 5th ed. 1999, New York: W. H. Freeman and Company. 37. Silbey, R.J. and R.A. Alberty, Physical Chemistry . 2000, New York, New York: John Wiley & Sons. 959.

50

## Acknowledgments

The authors appreciate the a ssistance of Mark Toso, A ndrew Sedeky, and Tom Higgins of the Minnesota Pollution Control Agency; Ileana Rhodes of Shell Global Solutions; Stephen Duirk, Said Hilal and Susan Richardson of the U.S. EPA, Office of Research and Development in Athens, Georgia. The aut hors also appreciate the comments from reviewers representing academia, industry and government.

51

## Appendix A Analytical Methods

Fuel Ethanol Analysis The undenatured fuel ethanol samples were directly injected into an Agilent 6890

GC with a 5973 MSD. The 2.0 μ L injected sample was split in the injector at a 200:1 ratio with the inject or temperature at 250  ̊ C. Separation of the compounds was achieved

with a 30m Restek Rtx-200 MS column with an ID of 250 μ m, film thickness of 0.5 μ m, and a flow rate of 0.7 mL / minute. Initial oven temperature was 40  ̊ C for 4 minutes, followed by a 1  ̊ C / minute temperature ramp to 50  ̊ C. A final temperature ramp of 30  ̊ C

/ minute to 250  ̊ C was used to elute late boilers and clean the column. Once reaching

250  ̊ C, there was a final hold time of 5.33 minut es. Total run time was 26 minutes. The transfer line to the MSD was kept at 280  ̊ C, the MS source at 230  ̊ C, and the MS quadrupole at 150  ̊ C for the entire analysis. The sa mple was ionized as it entered the MSD by electron impact. The MSD was turned on after a 1 minute solvent delay, and

scanned from 15 to 550 M/Z. Subsequently, chemical standards were obt ained and three calibration curves were developed for an Agilent 6890 gas chromatogr aph with a flame ionization detector (GCFID). For all the compounds except ethanol 1.0 μ L was injected and the split ratio and temperature programs were the same. Ethanol analysis was achieved by first diluting the sample in acetone to 0.5% of the starting c oncentration and only splitting the sample 50:1. Compound separation was achieved with a 30m J&W HP-5 column with an ID of

320 μ m, film thickness of 0.25 μ m, and flow of 0.5 mL per minute. Calibration curve points were 2.0%, 1.0%, 0.5%, 0.2%, 0.1%, a nd 0.05% by volume of each suspected

52compound. Linear correlation lines were compared to area counts from the fuel samples to determine the percentages of compounds in the samples. Because of overlapping retention times, 3-Methyl 1-Bu tanol and ethanol were calibrated separately from the rest of the compounds. An internal standard of 0.1% by volume of 1, 3-Dibromo-2-propanol was spiked into every sample. The Karl Fischer (KF) coulometric method was used to determine the water content in the ethanol sample s [36]. Samples were analyzed using a Brinkman Metrohm

Titrino 831 KF Coulometer wi th Coulomat AG reagent. This system detects trace amounts of water by titrating the sample to a bipotentiometric end point and is selective to water. One to three milliliters of sample was weighed to the nearest 0.0001 g. The sample was then injected into the titration vessel, and the sample weight was entered into the titrator software. The sample was automatically titrated by the instrument and the water content calculated by the software wh ich was displayed to the nearest 0.01%. Water content values were manually recorded into a laboratory notebook. 

### Phase Separation

Separation experiments were conducted by adding various amounts of deionized

water to a fixed amount of E-85 fuel at ambien t temperature. E-85: water ratios included 5:0.5, 5: 0.625, 5:0.75, 5:0.875, 5:1, 5:1.5, 5:2, 5:2.5, 5:3, 5:3.5, 5:4, 5:4.5, 1:1, 1:1.25, 1:1.5, 1:1.75, and 1:2. First, 20 ml of E-85 was transferred by class “A” volumetric pipette into a separatory funnel that was appropriately sized fo r the total volume expected. Amounts of deionized water were th en added to the E-85 to the desired ratio by class “A” volumetric pipette. The separatory flask was then gently shaken and vented

53three times before allowing the mixture to rema in undisturbed for five minutes in order to allow separation to occur. After five minutes the aqueous (bottom) phase was slowly and carefully drained into an appropriately sized graduated cylinder. The remaining oil (top) phase was then slowly and carefully draine d into an appropriately sized graduated cylinder. The volume of the liquid in each cylinder was then recorded for each phase. A screening method was developed for rapid assessment of phase separation potential, that was particularly useful since the available volume of sample was limited. Measured portions of three commercial ethanol/gasoline mixed samples (E10, E85, and E95) were placed in a 10 ml graduated cylinder. A burette was used to deliver 0.1 ml of deionized water at set increments. Sample mixing was obtained by a continual stirring of a magnetic stir bar at the base of the graduate d cylinder. Emulsions were allowed to stir for five minutes before any readings were ta ken. The affects of the addition of the water (emulsion and/or the presence of two phase behavior) was noted af ter each addition. The volume of the bottom phase (assumed to be ethanol/water) was read from the markings on the graduated cylinder. Shrinkage of the total volume was also noted by reading the total volume of the solution in the graduated cylinder compared to the initial ethanol/gasoline volume pl us the added water volume. Synthetic samples of approximately E25 and E35 were created by ad ding 1 ml and 2 ml of 100% Ethanol to 5

ml of E10. These were tested in the same manner as the E10.

54

## Appendix B Detected and tentatively identified chemicals from an ethanol plant in Minnesota [10].

Chemical Detected Chemical Tentatively Identified Chemical Tentatively Identified Plant Location: DDGS Dryer Stack

Methanol 1,3-butadiene 2-methyl-butanal

Ethanol 1,3-butadiene, 2-me thyl- 2-methyl-furan Toluene 1,3-pentadiene 2-methypropenal Ethylbenzene 1-2-propadiene 2-pentyl-furan Acetone 1-4-pentadiene 2-propen-1-ol Formaldehyde 1-decene 2-propenal Acetaldehyde 1-dodecene 3-methyl-butanal Acrolein 1-heptene 6-heptenoic acid Benzene 1-hexene acetaldehyde Styrene 1-methy-2-cyclopropene benzaldehyde Lactic Acid 1-nonene ethanol Acetic Acid 1-octene furan Furfuraldehyde 1-undecene hexanal 2-butanone Nitro-methane

2-butenal nonanal 2-furancarboxaldehyde propene 2-heptenal 2-methyl-1-pentene 2-methyl-2-propenal

55Chemical Detected Chemical Tentatively Identified Plant Location: Distillation Dryer Stack

Methanol 1 butanol 3-methyl

Ethanol 1 butanol 3-methyl, aceta Carbonyl Sulfide 1-butanol, 3methyl- (S)

Formaldehyde 1-butanol, 3methyl- aceta Acetaldehyde butane MEK/Butyraldehydes butane, 2, 2-dimethyl

m,p-Tolualdehyde butane, 2, 3-dimethyl butane, 2-methyl cyclopentane, methylethanol ethyl acetate heptane hexane hexane 2-methyl hexane, 3-methyl pentane pentane, 2 methyl 2-methyl-1-pentene 2-methyl-2-propenal

Chemical Detected Chemical Tentatively Identified

Plant Location: Fermetation Scrubber

Methanol 1 butanol 3-methyl

Ethanol 1 butanol 2-methyl Carbonyl Sulfide 1 butanol 2-methyl (s)

Formaldehyde 1-butanol, 3methyl- aceta Acetaldehyde 1,3-pentadiene Hydrogen Sulfide 1-propanol Dimethyl Sulfide 1-propanol, 2-methyl acetaldehyde dimethyl sulfide ethanol ethyl acetate formic acid

pentane propanoic acid

56

## Appendix C Ethanol and Water Mixtures

When water and ethanol form a mixture, a unique volumetric effect occurs: the resulting volume is less than the sum of th e individual water and ethanol volumes. This phenomenon of contracting volume is a resu lt of interstitial packing and molecular interaction (hydrogen bonding) between water and ethanol molecules in solution. Because the volume of the solution depends on its composition, it is convenient to

discuss volumetric effects of ethanol-water mixtures in terms of partial molar volume. The partial molar volume, V i , is defined as follows:

V

i = ( ∂ V/ ∂ n i ) T,p,nj . The equation above can be stated by saying that V i is the change in total volume per mole of “i” added, when some amount of “i” is a dded to the mixture at constant temperature, pressure and amount of other substances [ 37]. Using partial molar volumes, the total volume of a solution can be gi ven by the following equation:

V T = V 1 n 1 + V 2 n 2 +...+ V N n N

V T = ( ∂ V/ ∂ n 1 ) T,p,nj * n 1 + ( ∂ V/ ∂ n 2 ) T,p,nj * n 2 +...+ ( ∂ V/ ∂ n N ) T,p,nj * n N

The total volume of the solution can be discovered by determining the partial molar volumes of ethanol and water, as well as the mass fractions of the mixture. Partial

molar volumes of water and ethanol can be found using the equation below [30].

V

e = 

# ( υ + ω w ( ∂ V/ ∂ω e ) T,p,nj . 

# ) M e & V w = 

# ( υ + ω e ( ∂ V/ ∂ω w ) T,p,nj . 

# ) M w ,

In this equation, υ refers to the specific volume of the solution, ω represents the mass fraction, M is indicative of mo lecular weight, and the subscripts “e” and “w” refer to

57water and ethanol, respectively. The densities of 54 different water- ethanol mixtures are given by Pecar and Dolecek along with their respective mole fractions of ethanol. The

mass fraction of ethanol and its corresponding specific volume are calculated using the data provided for these different mixtures. Specific volumes are plotted against the mass

fraction of ethanol and the best fit curve is applied to the data-plot by the third degree polynomial. Then, the derivative of this pol ynomial is deduced, and the partial molar

volume can be determined. The total volume of solution can then be predicted using the following equation:

V T = ( ∂ V/ ∂ n e ) T,p,nj * n e + ( ∂ V/ ∂ n w ) T,p,nj * n 2 By assuming that 1 mole of solution is present, n e & n w can be set equal to the mole

fractions of ethanol a nd water, respectively. Using the equations above and data provided by Pecar & Dolecek it can be shown that approximately one mole of ethanol and a relatively small amount of water has a total volume nearly equal to the molar volume of ethanol. However, when significant amounts of both water and ethanol are present in a mi xture, the total volume is less than the

individual volumes of ethanol and water standing alone. A table illustrating these volumetric effects is provided with a maxi mum contraction of -3.4% occurring at an

ethanol mole fraction of 0.2745.

58

## Appendix D Comparison of results from the EPI Suite TM 

## calculator and SPARC for K ow 

## for 5 o 

## C and 25 o 

## C.

Figure 19 shows a comparison of log K ow results from SPARC at 5 o C and 15 o C,

EPI-Suite TM , and experimental data reported by EPI-Suite TM . Generally good agreement was seen among these sources. The SPARC results show more variation with temperature at higher K ow s than for the low values. Figure 20 shows assumed variability of one-half log unit in SPARC K ow results on both log-log and linear scal es. Note that as the value of

K ow increases so does the variability on the linear scale.

- 10 1 2 EPI Suite Reported Experimental Log K ow 3 -1 0 1 2 3Estimated Log Kow Comparison EPI Suite SPARC 5 C SPARC 25 C

Figure 19 Estimates from the EPA EPI Suite calculator, SPARC at 5 o C and 25 o C plotted against experimental results reported with EPI Suite results.

59-2 0 2 4 

### Log Median Value -2 0 2 4Log Median Value+/- 1/4log unit Vairation Median Median - 1/4 log unit Median + 1/4 log unit

0 200 400 600 800 1000 

### Median Value 0 400 800 1200 1600 2000

Figure 20 Example of variation in SPARC results given an assumed variabilit y (error) of one-half log unit. The left hand graph shows results on a log-log scale. The right hand graph shows the same variation on a linear scale.

60

## Appendix E SPARC Property Results for 5 o 

## C to 45 o 

## C

10 20 30 40 Temperature (C) 0 50000 100000 150000 200000 250000Solubility (mg/L) 1-Propanol

Isobutyl Alcohol

2-Methyl 1-Butanol

3-Methyl 1-Butanol

Figure 21 Solubility of the alcohols found in the wet and dry mill samples. Ethanol and methanol do not appear because their solubility is infinite.

10 20 30 40 Tempe r atu r e (C) 0 10000 20000 30000 40000 50000Solubility (mg/L) Ethyl Acetate

1,1-diethoxy ethane MTBE

Benzene

Figure 22 Solubility of ethyl acetate and 1,1- diethoxy ethane, compounds found in the wet mill sample. Solubilities of bezene and MTBE are plotted for comparison.

610 10 20 30 40 50 0 1E-005 2E-005 3E-005 4E-005 5E-005Henry's Law Coefficient(atm m3/mol)

0 10 20 30 40 50 0.1

1 10 100 1000Vapor Pressure(Torr)

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2Air PhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 Temperature (C) 0 0.2 0.4 0.6 0.8

1Octanol WaterPartition Coefficient 0 10 20 30 40 50 0 1E-005 2E-005 3E-005 4E-005 5E-005

0 10 20 30 40 50 0.1

1 10 100 1000

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2

0 10 20 30 40 50 Temperature (C) 0 0.2 0.4 0.6 0.8

1 

### Methanol Ethanol

0 10 20 30 40 50 0 1E-005 2E-005 3E-005WaterPhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 0 1E-005 2E-005 3E-005

Figure 23 Properties (Henry's Law coefficient, vapor pressure, air phase diffusion coefficient, octanol/water partition co efficient) for methanol an d ethanol estimated by the SPARC calculator.

620 10 20 30 40 50 0 1E-005 2E-005 3E-005 4E-005 5E-005Henry's Law Coefficient(atm m3/mol)

0 10 20 30 40 50 0.1

1 10 100 1000Vapor Pressure(Torr)

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2Air PhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 Temperature (C) 0 5 10 15Octanol WaterPartition Coefficient 0 10 20 30 40 50 0 1E-005 2E-005 3E-005 4E-005 5E-005

0 10 20 30 40 50 0.1

1 10 100 1000

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2

0 10 20 30 40 50 Temperature (C) 0 5 10 15 

### 1-Propanol Isobutyl Alcohol

0 10 20 30 40 50 0 1E-005 2E-005 3E-005WaterPhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 0 1E-005 2E-005 3E-005

Figure 24 Properties (Henry's Law coefficient, vapor pressure, air phase diffusion coefficient, octanol/water partition coefficient) for 1-propanol and isobutyl alcohol estimated by the SPARC calculator.

630 10 20 30 40 50 0 1E-005 2E-005 3E-005 4E-005 5E-005Henry's Law Coefficient(atm m3/mol)

0 10 20 30 40 50 0.1

1 10 100 1000Vapor Pressure(Torr)

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2Air PhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 Temperature (C) 0 10 20 30 40 50Octanol WaterPartition Coefficient 0 10 20 30 40 50 0 1E-005 2E-005 3E-005 4E-005 5E-005

0 10 20 30 40 50 0.1

1 10 100 1000

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2

0 10 20 30 40 50 Temperature (C) 0 10 20 30 40 50 

### 2-Methanol 1-Butanol 3-Methyl 1-Butanol

0 10 20 30 40 50 0 1E-005 2E-005 3E-005WaterPhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 0 1E-005 2E-005 3E-005

Figure 25 Properties (Henry's Law coefficient, vapor pressure, air phase diffusion coefficient, octanol/water partition coef ficient) for 2-methyl 1-butane and 3-methyl 1-butane estimated by the SPARC calculator.

640 10 20 30 40 50 0 0.0002 0.0004 0.0006 0.0008

0.001Henry's Law Coefficient(atm m3/mol)

0 10 20 30 40 50

0.1

1 10 100 1000Vapor Pressure(Torr)

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2Air PhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 Temperature (C) 0 2 4 6 8 10Octanol WaterPartition Coefficient 

### Ethyl Acetate

0 10 20 30 40 50 0 1E-005 2E-005 3E-005Water PhaseDiffusion Coefficient(cm2/s)

Figure 26 Properties (Henry's Law coefficient, va por pressure, air phase diffusion coefficient, octanol/water partition coeffici ent) for ethyl acetate estimated by the SPARC calculator.

650 10 20 30 40 50 0 0.0004 0.0008 0.0012 0.0016

0.002Henry's Law Coefficient(atm m3/mol)

0 10 20 30 40 50

0.1

1 10 100 1000Vapor Pressure(Torr)

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2Air PhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 Temperature (C) 0 2 4 6 8 10Octanol WaterPartition Coefficient 

### 1,1-Diethoxyethane

0 10 20 30 40 50 0 1E-005 2E-005 3E-005WaterPhaseDiffusion Coefficient(cm2/s)

Figure 27 Properties (Henry's Law coefficient, vapor pressure, air phase diffusion coefficient, octanol/water partition co efficient) for 1,1-diethoxyethane estimated by the SPARC calculator.

660 10 20 30 40 50 0 0.002 0.004 0.006 0.008

0.01Henry's Law Coefficient(atm m3/mol)

0 10 20 30 40 50

0.1

1 10 100 1000Vapor Pressure(Torr)

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2Air PhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 Temperature (C) 0 50 100 150 200Octanol WaterPartition Coefficient 0 10 20 30 40 50 0 0.002 0.004 0.006 0.008

0.01

0 10 20 30 40 50

0.1

1 10 100 1000

0 10 20 30 40 50 0 0.04 0.08 0.12 0.16

0.2

0 10 20 30 40 50 Temperature (C) 0 50 100 150 200 

### Benzene MTBE

0 10 20 30 40 50 0 1E-005 2E-005 3E-005WaterPhaseDiffusion Coefficient(cm2/s)

0 10 20 30 40 50 0 1E-005 2E-005 3E-005

Figure 28 Properties (Henry's Law coefficient, vapor pressure, air phase diffusion coefficient, octanol/water partition coeffi cient) for benzene and methyl tert -butyl ether (MTBE) estimated by the SPARC calculator.

67Please make all necessary changes on the below label, detach or copy, and return to the address in the upper left-hand corner. If you do not wish to receive these reports CHECK HERE □ ; detach, or copy this cover, and return to the address in the upper left-hand corner. PRESORTED STANDARD POSTAGE & FEES PAID EPA PERMIT No. G-35

Office of Research and Development (8101R) W ashington, DC 20460 Official Business Penalty for Private Use $ 300 EPA/600/R-09/037 April 2009 www.epa.gov



# v Recycled/Recyclable Printed with vegetable-based ink on paper that contains a minimum of 50% post-consumer fib content er processed chlorine free