1. DIMETHYL CARBONATE DMC The Next VOC Exempt Solvent
Kowa American Corp
Revised Jan 15, 2009

2. Status of VOC Exempt Program
Approx 50 chemicals or chemicals groups approved since inception of program (1977)
EPA will continue to add qualified chemicals to exempt list on a case by case basis
EPA will allow petitions on both a per gram and per mole reactivity comparison to their benchmark ethane reactivity using Maximum Incremental Reactivity (MIR) values
EPA will take into consideration toxicity and environmental factors in petition process

3. Previous VOC Exempt Coating Solvents
Realistically there are only a handful of VOC exempt solvents that are not HAPS (or ODS) and under $ 2.00/lb that formulators can consider for coating & adhesive solvents:
Acetone
Methyl acetate (MeAc)
tert-Butyl Acetate (tBAc)
p-Chlorobenzotrifluoride (PCBTF)

4. Solvents recently exempted by the EPA
Dimethyl Carbonate (DMC) & Propylene Carbonate exempted by EPA on Jan 13, 2009
Effective date for rule is 30 days from publication date of final rule in federal register
Each state and/or Air Management District must also approve, most states automatically approve by reference to the Federal VOC exempt approved list, some must add by adminstrative or legislative process, others like Calif. must do a full regulatory review.

5. Dimethyl Carbonate (DMC)
VOC exemption petition filed July 2004 by Kowa American Corp.
DMC has perhaps lowest MIR value of any liquid chemical in commercial use based on studies conducted by Dr. William Carter (study funded by Exxon Mobil Chemical)
Ultra-low MIR should allow for rapid approvals by the various states and AMD’s

6. MIR Reactivity Values MIR gram basis MIR mole basis DMC 0.06 5.4
Ethane
0.31
9.3
Acetone
0.43
25.0
Methyl Acetate
0.07
5.2
BTF
0.26
12.1

7. DMC General Properties
DMC is a colorless, fast evaporating solvent
Has substantial polar nature, and moderate h-bonding strength effective in replacing esters, glycol ethers and ketones in formulations
Has low toxicity, an unobjectionable methanol type odor and low skin irritation
Freezes at 2 – 4 ºC (36 –38 ºF)
Flammable Liquid, Flash point 17 ºC (63 ºF)

8. DMC Evaporation Rate
Fast to moderate evaporation rate (3.22 –3.4, BuAC = 1.0), similar to tBAC (2.8), BTF (2.8) and isopropyl acetate (3.0)
Can be used to as slightly slower evaporating replacement for MEK (3.8), Ethyl Acetate ( ), or as faster evaporating replacement for IPA (1.7), MPK (2.3), Ethanol (1.8) and MIBK (1.6)

9. DMC - Flammability DMC has a flashpoint of 63ºF (17ºC)
Flammability will limit use in consumer coatings or indoor applications
Flammability risk still much lower than acetone (-4º F), ethyl acetate (26ºF) or MEK (26ºF), which DMC can readily replace
Flammability as minor solvent (<13.9%) in water borne coatings needs to be evaluated

10. Flashpoint, E. rate, Boiling point
Evaporation Rate BuAc =1.0
Flashpoint ºF
Boiling point ºC
Acetone
6.3 -4 56
Ethyl ace
4.1 27 75
DMC
3.22 63 90
BTF
2.8 54
102
tBAc 40 98
PCBTF .9
109*
139

11. DMC Solubility Properties
Hildebrand solubility parameter 20.3 Mpa
Hansen solubility parameters: Dispersion polar 3.9 h-bond 9.7 molar vol. 84.2
Similar solubility parameters to some common glycol ethers: cellosolve acetate, ethylene glycol butyl ether acetate, propylene glycol monobutyl ether and propylene glycol monoethyl ether acetate

12. DMC Solubility Properties
DMC has been described as useful in acrylics, urethane and alkyd systems as a co-solvent
DMC is miscible with almost all organic solvents
DMC would easily replace oxygenated solvents like esters and glycol ethers
DMC should replace alcohols and ketones with appropriate co-solvents

13. DMC – Toxicity
DMC has low acute oral toxicity (LD50 rat 12,900 mg/Kg, LD50 mouse 6,000 mg/Kg)
Kowa has a recommend exposure limit TWA of 200 ppm, which is based on exposure limits of methanol , one of its primary metabolites
DMC was found to be negative in mutagenic tests (in vitro Ames & comet assay)
Readily biodegradable and has low potential to bioaccumulate, possibly toxic to algae
Not expected to be toxic to fish or bacteria

14. DMC - Azeotropes
There have been a few cryptic references in literature to DMC forming azeotropes with alcohols and ketones without further data
Azeotropes using DMC could be the “wild card” in developing coating or cleaning formulations, substantially changing the evaporation rate, solubility and perhaps flammability profiles

15. Propylene Carbonate
Propylene Carbonate is a very slow evaporating solvent (evaporation rate <.005, BuAc =1). This will restrict its solvent use.
Low viscosity 2.4 cps, high flashpoint 253º F
Practically non-toxic by oral, dermal or Inhalation, slight skin irritant, eye irritant
Available from Kowa from same Chinese source as our Dimethyl Carbonate.

16. Benzotrifluoride Status
Benzotrifluoride (BTF) –was dropped from same review process as DMC & PC due to recently revised MIR values showing it is slightly higher than the Ethane MIR standard
Kowa intends to re-apply for consideration of BTF, now that DMC is approved
BTF is a perfect toluene substitute: similar solvency, aromatic, fast evaporating (2.8)

17. Benzotrifluoride - BTF
Kowa American is a co-petitioner on this VOC exemption petition
Aromatic solvent useful for replacing toluene, aromatics and aliphatic solvents
Evaporation rate 2.8, flash point 54ºF
Clear colorless liquid, 100 ppm TLV
Slightly irritating to skin & respiratory tract
Readily volatilizes from ground and water