Dimethyl carbonate

Dimethyl carbonate (DMC) is an organic compound with the formula OC(OCH3)2. It is a colourless, flammable liquid. It is classified as a carbonate ester. This compound has found use as a methylating agent and more recently as a solvent that is exempt from the restrictions placed on most volatile organic compounds (VOCs) in the US.[1] Dimethyl carbonate is often considered to be a green reagent.[2]

Dimethyl carbonate
Dimethyl carbonate
Ball-and-stick model of dimethyl carbonate
Names
IUPAC name
Dimethyl carbonate
Other names
DMC
Methyl carbonate
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.009.527
Properties
C3H6O3
Molar mass 90.078 g·mol−1
Appearance Clear liquid
Density 1.069-1.073 g/mL
Melting point 2 to 4 °C (36 to 39 °F; 275 to 277 K)
Boiling point 90 °C (194 °F; 363 K)
13.9 g/100 mL
Hazards
Main hazards Flammable
Flash point 17 °C (63 °F; 290 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Production

World production in 1997 was estimated at 1000 barrels a day.[3] Production of dimethyl carbonate worldwide is limited to Asia, the Middle East, and Europe.

Dimethyl carbonate is traditionally prepared by the reaction of phosgene and methanol. Methyl chloroformate is produced as an intermediate:

COCl2 + CH3OH → CH3OCOCl + HCl
CH3OCOCl + CH3OH → CH3OCO2CH3 + HCl

This synthesis route has been largely replaced by oxidative carbonylation. In this process, carbon monoxide and an oxidizer provide the equivalent of CO2+:[4][5]

CO + 1/2 O2 + 2 CH3OH → (CH3O)2CO + H2O

It can also produced industrially by a transesterification of ethylene carbonate or propylene carbonate and methanol, which also affords respectively ethylene glycol or propylene glycol.

Reactions and potential applications

Methylating agent

Dimethyl carbonate methylates anilines, phenols, and carboxylic acids, but many of these reactions require the use of an autoclave.[6][7]

Methylation of phenylacetic acid by dimethyl carbonate promoted by DBU
Methylation of phenylacetic acid by dimethyl carbonate promoted by DBU

Dimethyl carbonate's main benefit over other methylating reagents such as iodomethane and dimethyl sulfate is its low toxicity. Additionally, it is biodegradable.[4] Unfortunately, it is a relatively weak methylating agent compared to these traditional reagents.

Solvent

In the US, dimethyl carbonate was exempted under the definition of volatile organic compounds (VOCs) by the U.S. EPA in 2009.[8] Due to its classification as VOC exempt, dimethyl carbonate has grown in popularity and applications as a replacement for methyl ethyl ketone (MEK), tert-butyl acetate, and parachlorobenzotrifluoride. Dimethyl carbonate has an ester- or alcohol-like odor, which is more favorable to users than most hydrocarbon solvents it replaces. Dimethyl carbonate has an evaporation rate of 3.22 (butyl acetate = 1.0), which slightly slower than MEK (3.8) and ethyl acetate (4.1), and faster than toluene (2.0) and isopropanol (1.7). Dimethyl carbonate has solubility profile similar to common glycol ethers, meaning dimethyl carbonate can dissolve most common coating resins except perhaps rubber based resins. Hildebrand solubility parameter is 20.3 MPa and Hansen solubility parameters are: dispersion = 15.5, polar = 3.9, H bonding = 9.7.[9] Dimethyl carbonate is partially soluble in water up to 13%, however it is hydrolyzed in water-based systems over time to methanol and CO2 unless properly buffered. Dimethyl carbonate can freeze at same temperatures as water, it can be thawed out with no loss of properties to itself or coatings based on dimethyl carbonate.

Intermediate in polycarbonate synthesis

A large captive use of dimethyl carbonate is for the production of diphenyl carbonate through transesterification with phenol. Diphenyl carbonate is a widely used raw material for the synthesis of bisphenol-A-polycarbonate in a melt polycondensation process. The most common route is described by Fukuoka, of the Japanese "Asahi Kasei" chemical corporation.[10]

Alternative fuel additive

There is also interest in using this compound as a fuel oxygenate additive.[3]

Safety

DMC is a flammable liquid with a flash point of 17 °C (63 °F), which limits its use in consumer and indoor applications. DMC is still safer than acetone, methyl acetate and methyl ethyl ketone from a flammability point of view. DMC has a recommended exposure limit (REL) limit of 100 ppm by inhalation over an 8-hour work day, which is similar to that of a number of common industrial solvents (toluene, methyl ethyl ketone). Workers should wear protective organic vapor respirators when using DMC indoors or in other conditions where concentrations exceed the REL. DMC is metabolized by the body to methanol and carbon dioxide, so accidental ingestion should be treated in the same manner as methanol poisoning.

See also

References

  1. ^ "Update: U.S. EPA Exempt Volatile Organic Compounds". American Coatings Association. 2018-01-30. Retrieved 2019-03-20.
  2. ^ Kreutzberger., Charles B. (2001), "Chloroformates and Carbonates", Kirk-Othmer Encyclopedia of Chemical Technology, New York: John Wiley, doi:10.1002/0471238961.0301180204011312.a01.pub2, ISBN 9780471238966
  3. ^ a b Pacheco, Michael A.; Marshall, Christopher L. (1997). "Review of Dimethyl Carbonate (DMC) Manufacture and Its Characteristics as a Fuel Additive". Energy Fuels. 11: 2–29. doi:10.1021/ef9600974.
  4. ^ a b Pietro Tundo & Maurizio Selva (2002). "The Chemistry of Dimethyl Carbonate". Acc. Chem. Res. 35 (9): 706–16. doi:10.1021/ar010076f.
  5. ^ Hans-Josef Buysch. "Carbonic Esters". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a05_197/full.
  6. ^ Shieh, Wen-Chung; Dell, Stephen; Repič, Oljan (2002). "Nucleophilic Catalysis with 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) for the Esterification of Carboxylic Acids with Dimethyl Carbonate". J. Org. Chem. 67 (7): 2188–2191. doi:10.1021/jo011036s.
  7. ^ Shieh, Wen-Chung; Dell, Steven; Repič, Oljan (2001). "1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) and Microwave-Accelerated Green Chemistry in Methylation of Phenols, Indoles, and Benzimidazoles with Dimethyl Carbonate". Organic Letters. 3 (26): 4279–81. doi:10.1021/ol016949n. PMID 11784197.
  8. ^ http://www.epa.gov/ttn/oarpg/t1/fact_sheets/voc_exemp01011309.pdf. Information about the EPA's action on exempting dimethyl carbonate as a VOC and petitioner's background information, public comments and other references are available electronically at http://www.regulations.gov, EPA’s electronic public docket and comment system. The docket number for this action is Docket ID No. EPA-HQ-OAR-2006-0948. See http://www.epa.gov/ttn/oarpg/t1pfpr.html and scroll down to Jan 13, 2009 pdf for the rule.
  9. ^ Kanegsberg, Barbara; Kanegsberg, Edward (2011-04-04). Handbook for Critical Cleaning: Cleaning Agents and Systems, Second Edition (Second ed.). CRC Press. p. 16. ISBN 9781439828281.
  10. ^ Non phosgene Polycarbonate from CO2 - Industrialization of Green Chemical Process, Shinsuke Fukuoka (Asahi Kasei Chemicals Corporation)
C3H6O3

The molecular formula C3H6O3 may refer to:

Dihydroxyacetone

Dimethyl carbonate

Glyceraldehyde

3-Hydroxypropionic acid

Lactic acid

Trioxanes

1,2,4-Trioxane

1,3,5-Trioxane

Carbonate ester

A carbonate ester (organic carbonate or organocarbonate) is an ester of carbonic acid. This functional group consists of a carbonyl group flanked by two alkoxy groups. The general structure of these carbonates is R1O(C=O)OR2 and they are related to esters R1O(C=O)R and ethers R1OR2 and also to the inorganic carbonates.

Monomers of polycarbonate (e.g. Lexan) are linked by carbonate groups. These polycarbonates are used in eyeglass lenses, compact discs, and bulletproof glass. Small carbonate esters like dimethyl carbonate, ethylene carbonate, propylene carbonate are used as solvents. Dimethyl carbonate is also a mild methylating agent.

Carbonylation

Carbonylation refers to reactions that introduce carbon monoxide into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. The term carbonylation also refers to oxidation of protein side chains.

Dicopper chloride trihydroxide

Dicopper chloride trihydroxide is the chemical compound with the formula Cu2(OH)3Cl. It is often referred to as tribasic copper chloride (TBCC), copper trihydroxyl chloride or copper hydroxychloride. It is a greenish crystalline solid encountered in mineral deposits, metal corrosion products, industrial products, art and archeological objects, and some living systems. It was originally manufactured on an industrial scale as a precipitated material used as either a chemical intermediate or a fungicide. Since 1994, a purified, crystallized product has been produced at the scale of thousands of tons per year, and used extensively as a nutritional supplement for animals.

Dimethyl oxalate

Dimethyl oxalate is the organic compound with the formula (CH3O2C)2. It is the dimethyl ester of oxalic acid. Dimethyl oxalate is a colorless or white solid that is soluble in water.

Dimethyl sulfate

Dimethyl sulfate is a chemical compound with formula (CH3O)2SO2. As the diester of methanol and sulfuric acid, its formula is often written as (CH3)2SO4 or even Me2SO4, where CH3 or Me is methyl. Me2SO4 is mainly used as a methylating agent in organic synthesis.

Me2SO4 is a colourless oily liquid with a slight onion-like odour (although smelling it would represent significant exposure). Like all strong alkylating agents, Me2SO4 is extremely toxic. Its use as a laboratory reagent has been superseded to some extent by methyl triflate, CF3SO3CH3, the methyl ester of trifluoromethanesulfonic acid.

Diphenyl carbonate

Diphenyl carbonate is the organic compound with the formula (C6H5O)2CO. It is classified as an acyclic carbonate ester. It is a colorless solid. It is both a monomer in combination with bisphenol A in the production of polycarbonate polymers and a product of the decomposition of polycarbonates.

Dual carbon battery

A dual carbon battery is one that uses carbon for both the cathode and the anode.

Ethylene carbonate

Ethylene carbonate (sometimes abbreviated EC) is the organic compound with the formula (CH2O)2CO. It is classified as the carbonate ester of ethylene glycol and carbonic acid. At room temperature (25 °C) ethylene carbonate is a transparent crystalline solid, practically odorless and colorless, and somewhat soluble in water. In the liquid state (m.p. 34-37 °C) it is a colorless odorless liquid.

List of UN numbers 1101 to 1200

The UN numbers from UN1101 to UN1200 as assigned by the United Nations Committee of Experts on the Transport of Dangerous Goods.

Lithium hexafluorophosphate

Lithium hexafluorophosphate is an inorganic compound with the formula LiPF6. It is a white crystalline powder. It is used in commercial secondary batteries, an application that exploits its high solubility in non aqueous, polar solvents. Specifically, solutions of lithium hexafluorophosphate in carbonate blends of ethylene carbonate, dimethyl carbonate, diethyl carbonate and/or ethyl methyl carbonate, with a small amount of one or many additives like vinylene carbonate, serve as state-of-the-art electrolytes in lithium-ion batteries. This application also exploits the inertness of the hexafluorophosphate anion toward strong reducing agents, such as lithium metal.

The salt is relatively stable thermally, but loses 50% weight at 200 °C (392 °F). It hydrolyzes near 70 °C (158 °F) according to the following equation:

LiPF6 + H2O → HF + PF5 + LiOHOwing to the Lewis acidity of the Li+ ions, LiPF6 also catalyses the tetrahydropyranylation of tertiary alcohols.In lithium-ion batteries, LiPF6 reacts with Li2CO3 in the following way, which could be catalysed by small amounts of HF:

LiPF6 + Li2CO3 → POF3 + CO2 + 3 LiFA recent research also proposed, based on nuclear magnetic resonance results and density functional theory calculations, that LiPF6 could react in a mixture of ethylene carbonate and dimethyl carbonate with alumina powder or alumina coated lithium-ion batteries cathode materials to form lithium difluorophosphate and alumina oxyfluoride via the reaction:

2 Al2O3 (s) + x LiPF6 (solv) → 2 Al2O3-xF2x (s) + x LiPO2F2 (solv)Since lithium difluorophosphate is known to improve the performance of lithium-ion batteries, this suggest a new mechanism of action for alumina coatings in lithium-ion batteries.

Methyl carbamate

Methyl carbamate (also called methylurethane, or urethylane) is an organic compound and the simplest ester of carbamic acid (H2NCO2H). It is a colourless solid.Methyl carbamate is prepared by the reaction of methanol and urea:

CO(NH2)2 + CH3OH → CH3OC(O)NH2 + NH3It also forms in the reaction of ammonia with methyl chloroformate or dimethyl carbonate.

Methyl tert-butyl ether

Methyl tert-butyl ether (MTBE), also known as tert-butyl methyl ether, is an organic compound with a structural formula (CH3)3COCH3. MTBE is a volatile, flammable, and colorless liquid that is sparingly soluble in water. It has a minty smell vaguely reminiscent of diethyl ether, leading to unpleasant taste and odor in water. MTBE is a blending component of gasoline, used as an oxygenate to raise the octane number and to replace lead. Its use is controversial in some parts of the world, such as the US, because of contamination of groundwater, which was followed by legislation favoring ethanol. However, worldwide production of MTBE has been constant owing to growth in Asian markets.

Methylation

In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group, rather than a larger carbon chain, replacing a hydrogen atom. These terms are commonly used in chemistry, biochemistry, soil science, and the biological sciences.

In biological systems, methylation is catalyzed by enzymes; such methylation can be involved in modification of heavy metals, regulation of gene expression, regulation of protein function, and RNA processing. In vitro methylation of tissue samples is also one method for reducing certain histological staining artifacts. The counterpart of methylation is called demethylation.

Triphosgene

Triphosgene (bis(trichloromethyl) carbonate (BTC), C3Cl6O3) is a chemical compound that is used as a safer substitute for phosgene, because, at room temperature, it is a solid crystal, as opposed to phosgene, which is a gas. Triphosgene crystals decompose above 200 °C.

Triuret

Triuret is an organic compound with the formula (H2NC(O)NH)2CO. It is a product from the pyrolysis of urea. Triuret is a colorless, crystalline, hygroscopic solid, slightly soluble in cold water or ether, and more soluble in hot water. It is a planar molecule. The central carbonyl is hydrogen-bonded to both terminal amino groups.

Uranyl zinc acetate

Uranyl zinc acetate (ZnUO2(CH3COO)4) is a compound of uranium.

Uranyl zinc acetate is used as a laboratory reagent in the determination of sodium concentrations of solutions using a method of quantitatively precipitating sodium with uranyl zinc acetate and gravimetrically determining the sodium as uranyl zinc sodium acetate, (UO2)3ZnNa(CH3CO2)9·6H2O. The presence of caesium and rubidium does not interfere with this reaction, but the presence of potassium and lithium must be removed prior to analysis.This method was important to determine Na in urine for diagnostic purposes. Zinc uranyl acetate is sometimes called "sodium reagent" since pale yellow NaZn(UO2)3(C2H3O2)9 is one of the very few insoluble sodium compounds.

VOC exempt solvent

VOC exempt solvents are organic compounds that are exempt from restrictions placed on most volatile organic compounds (VOCs) in the United States. This class currently includes acetone, dimethyl carbonate, methyl acetate, parachlorobenzotrifluoride (Oxsol 100), tert-butyl acetate, and propylene carbonate.

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