1,4-DMN; 2,6-DIPN

055802; 055803

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

MEMORANDUM

DATE: August 22, 2012

SUBJECT: Product Chemistry Scoping Document for the Registration Review of 

Dimethylnaphthalene (1,4

Registration Review Case #: 

PC Codes: 055802, 055803

CAS Numbers: 571-

Chemical Class: Biochemical

Review Type: Product Chemistry

FROM: Gina Burnett, M.S., Biologist

Biochemical Pesticides Branch

Biopesticides & Pollution Prevention Division (7511P)

TO: Colin Walsh, Regulatory

Biochemical Pesticides Branch

Biopesticides & Pollution Prevention Division (7511P) 

AND: Leonard Cole, Regulatory

Biochemical Pesticides Branch

Biopesticides & Pollution Prevention Division (7511P) 

ACTION REQUESTED

A preliminary assessment of available information on product chemistry data associated with the 

biopesticides 1,4-dimethylnaphthalene (1,4

in support of the development of a Registration Revie

Registration Review 

 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

Product Chemistry Scoping Document for the Registration Review of 

Dimethylnaphthalene (1,4-DMN) and 2,6- Diisopropylnaphthalene (2,6

Registration Review Case #: 6029

055802, 055803

-58-4, 24157-81-1

Biochemical

Review Type: Product Chemistry

M.S., Biologist /s/ 8/22/12

Biochemical Pesticides Branch

Biopesticides & Pollution Prevention Division (7511P)

, Regulatory Action Leader

Biochemical Pesticides Branch

Biopesticides & Pollution Prevention Division (7511P) 

, Regulatory Action Leader

Biochemical Pesticides Branch

Biopesticides & Pollution Prevention Division (7511P) 

A preliminary assessment of available information on product chemistry data associated with the 

imethylnaphthalene (1,4-DMN) and 2,6- diisopropylnaphthalene (2,6

in support of the development of a Registration Review Work Plan.

Registration Review Case #: 6029

 Product Chemistry

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

Product Chemistry Scoping Document for the Registration Review of 1,4-

Diisopropylnaphthalene (2,6-DIPN). 

A preliminary assessment of available information on product chemistry data associated with the 

iisopropylnaphthalene (2,6-DIPN)
1,4-DMN; 2,6-DIPN Registration Review Case #: 6029

055802; 055803 Product Chemistry

Introduction

The Agency has determined that all necessary product chemistry information is available 

on the pesticide active ingredients 1,4-dimethylenaphthalene (1,4-DMN) and 2,6-

diisopropylnaphthalene (2,6-DIPN) with the exception of the UV/Visible light absorption 

data requirement (OCSPP Guideline 830.7050). This data requirement has not been 

fulfilled for either chemical. The Agency requires UV/Visible light absorption data for all 

technical grade active ingredients. 

1,4-DMN is a biochemical pesticide intended for use as a growth regulator (potato sprout 

inhibitor). The first product containing this active ingredient was registered with the Agency in 

1994. Currently, there are four active registrations containing 1,4-DMN; one manufacturing use 

product (MUP) and three end-use products (EPs). A tolerance exemption listed at 40 CFR

1180.1142 establishes an exemption from the requirement of a tolerance for residues of 1,4-

DMN when applied post harvest to potatoes in accordance with good agricultural practices.

2,6-DIPN is also a biochemical pesticide intended for use as a growth regulator (potato sprout 

inhibitor). The first product containing this active ingredient was registered with the Agency in 

2003. Currently, there are two active registrations containing 2,6-DIPN. A tolerance for residues

listed at 40 CFR 180.590 establishes residue levels for 2,6-DIPN and its metabolites and 

degredates in potato, cattle, goat horse, milk and sheep.

Concerning the product chemistry of 1,4-DMN and 2,6-DIPN, all biochemical pesticide data 

requirements for the technical grade active ingredients have been satisfied and are summarized in 

Tables 3 and 4, respectively. UV/Visible light absorption data is the only product chemistry data 

outstanding for the products currently registered. Future registrations must adequately address all 

of the biochemical pesticides product chemistry data requirements.
1,4-DMN; 2,6-DIPN Registration Review Case #: 6029

055802; 055803 Product Chemistry

3

Table 1. Product Identity and Composition for 1,4-DMN

Common Name 1,4-Dimethylnaphthalene (1,4-DMN)

Chemical Name, IUPAC Naphthalene, 1,4-dimethylMolecular Weight 156.22

PC Code 055802

CAS Registry Number 571-58-4

Empirical Formula C12H12

Registration Review Case Number 6029

Chemical Structure

Table 2. Product Identity and Composition for 2,6-DIPN

Common Name 2,6-Diisopropylnaphthalene (2,6-DIPN)

Chemical Name, IUPAC Naphthalene, 2,6-bis(1-methylethyl)

Molecular Weight 212.33

PC Code 055803

CAS Registry Number 24157-81-1

Empirical Formula C16H20

Registration Review Case Number 6029

Chemical Structure
1,4-DMN; 2,6-DIPN Registration Review Case #: 6029

055802; 055803 Product Chemistry

4

Product Chemistry Summary

The Agency has conducted a review of the available product chemistry data and information for 

1,4-DMN. These data are summarized in Table 3, below.

Table 3. Biochemical Pesticides Product Chemistry Data Requirements for 1,4-DMN

Guideline No. Physical and Chemical 

Properties

Status1 Value MRID

830.1100 Product Identity and 

Composition

A Refer to Table 1. -

830.1200 Description of starting 

materials, production and 

formulation process

A CBI -

830.1400 Discussion of formation of 

impurities

A CBI -

830.1700 Preliminary analysis A CBI -

830.6302 Color A Pale yellow to 

colorless

43082506

830.6303 Physical state A Liquid at room 

temperature

43082506

830.6304 Odor A Petroleum 

distillate

43082506

830.6313 Stability to normal and 

elevated temperatures, 

metals and metal ions

A Stable at normal 

temp.; 6-7% loss 

at elevated 

temp.; stable in 

presence of 

metals. 

43082509

830.7000 pH A 5.9 at 25oC 43082506

830.7050 UV/Visible light absorption N/D - -

830.7200 Melting point/melting range N/A N/A; not a solid -

830.7220 Boiling point/boiling range A 264oC 43280506

830.7300 Density A 1.014 g/ml at 

25oC

43280506

830.7520 Particle size, fiber length, 

and diameter distribution

N/A N/A; soluble in 

water

-

830.7550

830.7560

830.7570

Partition coefficient (nOctanol/Water)N/A N/A; soluble in 

water

-

830.7840 Water solubility A Soluble at 

5.1ppm

43082507

830.7950 Vapor pressure A 1.88x10-2 Torr at 

25oC

43082508

1. A=Acceptable. N/A=Not Applicable. N/D=Not Determined.
1,4-DMN; 2,6-DIPN Registration Review Case #: 6029

055802; 055803 Product Chemistry

5

The Agency has conducted a review of the available product chemistry data and information for 

2,6-DIPN. These data are summarized in Table 4, below.

Table 4. Biochemical Pesticides Product Chemistry Data Requirements for 2,6-DIPN

Guideline No. Physical and Chemical 

Properties

Status1 Value MRID

830.1100 Product Identity and 

Composition

A Refer to Table 

1.

-

830.1200 Description of starting 

materials, production and 

formulation process

A CBI -

830.1400 Discussion of formation of 

impurities

A CBI -

830.1700 Preliminary analysis A CBI -

830.6302 Color A Munsell color 

systems: N 9.5 

90.0% R

44614103

830.6303 Physical state A Crystalline 

solid at 25oC

44614103

830.6304 Odor A No noticeable 

odor

44614103

830.6313 Stability to normal and 

elevated temperatures, 

metals and metal ions

A Stable at 

normal and 

elevated

temperatures; 

stable in 

presence of Al 

and Zn, 7% 

reduction in 

presence of Cu

44614103

830.7000 pH A 6.00 at 20oC 44614103

830.7050 UV/Visible light absorption N/D - -

830.7200 Melting point/melting range A 67.8oC to 

68.9oC

44614103

830.7220 Boiling point/boiling range N/A N/A; not a 

liquid

-

830.7300 Density A 0.49 g/ml at 

25oC

44614103

830.7520 Particle size, fiber length, 

and diameter distribution

N/A N/A; soluble 

in water

-

830.7550

830.7560

830.7570

Partition coefficient (nOctanol/Water)A Soluble in 1-

octanol at 

39,559ppm

44614103

830.7840 Water solubility A 0.02ppm 44614103

830.7950 Vapor pressure A 6.1x10-4 Torr 

at 25

oC

44614103

1. A=Acceptable. N/A=Not Applicable. N/D=Not Determined.
1,4-DMN; 2,6-DIPN Registration Review Case #: 6029

055802; 055803 Product Chemistry

6

References

Irving, J.W., Pesticide Assessment Guidelines, Subdivision M, Series: 151-17, (Physical and 

Chemical Properties). Study performed by DARTEC, Inc. and submitted to EPA by Plate 

Chemical Co. MRID 446141-03. 1998.

Lorence, P.J., Vargyas, L.D., and J.R. Marat. 1,4-DMN Batch H5510-Color, Physical State, 

Odor, Boiling Point, Specific Gravity, PH, Flammability, Impact Explodability, 

Viscosity, Lab Project Number 4373-93-0226-AS. Private study performed by Ricerca, 

Inc. and submitted to EPA by D-I-1-4, Inc. MRID 430825-06. 1993. 

Lorence, P.J., Vargyas, L.D., and J.R. Marat. 1,4-DMN Solubility, Lab Project Number 4373-93-

0250-AS. Private study performed by Ricerca, Inc. and submitted to EPA by D-I-1-4, Inc. 

MRID 430825-07. 1993. 

Lorence, P.J., Vargyas, L.D., and J.R. Marat. 1,4-DMN – Vapor Pressure. Lab Project Number 

4373-93-0249-AS. Private study performed by Ricerca, Inc. and submitted to EPA by DI-1-4, Inc. MRID 430825-08. 1993. 

Lorence, P.J., Vargyas, L.D., and J.R. Marat. 1,4-DMN Stability, Lab Project Number 4373-93-

0247-AS. Private study performed by Ricerca, Inc. and submitted to EPA by D-I-1-4, Inc. 

MRID 430825-09. 1993. 

National Organic Standards Board Technical Advisory Panel (TAP) Review . 1,4-

dimethylnaphthalene for use as a post-harvest adjuvant. 

http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5057592. 

8/14/2012.

PubChem. http://pubchem.ncbi.nlm.nih.gov/. 8/14/2012.