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      	UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
       		WASHINGTON, D.C. 20460
      
      
      
      
                                          
                                                                               
                             OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION


MEMORANDUM

DATE: 		August 22, 2012


SUBJECT:	Product Chemistry Scoping Document for the Registration Review of 1,4-Dimethylnaphthalene (1,4-DMN) and 2,6- Diisopropylnaphthalene (2,6-DIPN).  

            Registration Review Case #: 6029
            PC Codes: 055802, 055803			
            CAS Numbers: 571-58-4, 24157-81-1				
            Chemical Class: Biochemical
            Review Type: Product Chemistry
                                                                  
FROM:		Gina Burnett, M.S., Biologist   /s/    8/22/12
            Biochemical Pesticides Branch
            Biopesticides & Pollution Prevention Division (7511P)

TO:			Colin Walsh, Regulatory Action Leader
            Biochemical Pesticides Branch
            Biopesticides & Pollution Prevention Division (7511P) 

AND:			Leonard Cole, Regulatory Action Leader
            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-DMN) and 2,6- diisopropylnaphthalene (2,6-DIPN) in support of the development of a Registration Review Work Plan.



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.






Table 1. Product Identity and Composition for 1,4-DMN
Common Name
1,4-Dimethylnaphthalene (1,4-DMN)
Chemical Name, IUPAC
Naphthalene, 1,4-dimethyl-
Molecular 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
                                       



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
                                   Status[1]
                                     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 25[o]C
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
264[o]C
43280506
830.7300
Density
                                       A
1.014 g/ml at 25[o]C
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 (n-Octanol/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 25[o]C
43082508
   1. A=Acceptable. N/A=Not Applicable. N/D=Not Determined.





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
                                   Status[1]
                                     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 25[o]C
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 20[o]C
44614103
830.7050
UV/Visible light absorption

                                      N/D
                                       -
                                       -
830.7200
Melting point/melting range
                                       A
67.8[o]C to 68.9[o]C
44614103
830.7220
Boiling point/boiling range
                                      N/A
                               N/A; not a liquid
                                       -
830.7300
Density
                                       A
0.49 g/ml at 25[o]C
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 (n-Octanol/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[o]C
44614103
   1. A=Acceptable. N/A=Not Applicable. N/D=Not Determined.


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 D-I-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.

