DMC Market Potential Needs to Be Developed   

By Sun Yuxiao   

Dimethyl carbonate (DMC) has excellent reaction activity and very low toxicity. It is an important environmental friendly intermediate for organic synthesis.

Large-scale development

China has more than 20 DMC producers, with a combined capacity of over 200 000 t/a. The biggest domestic DMC producer is Shandong Shida Shenghua Chemical Co., Ltd. It has a capacity of 55 000 t/a, accounting for around 30% of the national total. Dongying Hi-tech Spring Chemical Industry Co., Ltd. and Hebei Chaoyang Chemical Co., Ltd. follow close behind.
   Through more than 20 years of research and practice, DMC production processes in China have developed rapidly. Production units using the outdated phosgene process have all been shut down. The advanced ester exchange process is becoming well developed and several such production units with a capacity of over 10 000 t/a have been constructed. The new liquid-phase carbonyl oxidation process has entered the commercialization stage and two production units using this process have been constructed. The ester exchange process is relatively simple and mature. It features easily available raw materials, small investment, low cost and no environmental pollution. It has become the major process for DMC production in China, and the combined capacity of units using the process accounts for over 90% of the total.

Extensive consumption sectors

China is one of the world's major DMC producers and exporters. The output, the consumption and the export volume of DMC have all grown rapidly in recent years. China produced around 150 000 tons of DMC in 2008 and exported more than one fourth of it. Major export targets include the United States, Japan, Italy, Korea and India.
   China consumed 122 000 tons of DMC in 2008. Nearly a half of that was used to make coatings and adhesives and the balance was used in the pharmaceutical and pesticide sectors.
   Coatings and adhesive sectors: DMC is an environmental friendly solvent. Owing to its relatively low price, DMC can replace other solvents such as toluene, xylene, ethyl acetate, butyl acetate, acetone and butanone in coatings and adhesive sectors and the application prospect is bright.
   Pharmaceutical sector: In the pharmaceutical sector DMC is mainly used as methylating agent to replace high-toxicity dimentyl sulfate. It is also used in the synthesis of anti-infective drugs, analgesic-antipyretic drugs, vitamins and central nervous system drugs. The domestic pharmaceutical sector consumed around 8 000 tons of DMC in 2008.
   Bis(trichloromethyl) carbonate sector: The production of bis(trichloromethyl) carbonate in China uses the DMC process. In the long run, bis(trichloromethyl) carbonate used as a substitute for phosgene will have considerable development space. Output of bis(trichloromethyl) carbonate in China reached 10 000 tons in 2008, consuming around 3 000 tons of DMC.
   Battery electrolyte sector: The application of carbonates in the battery electrolyte sector has aroused widespread interest. Mobile appliances such as cellular phones, portable computers, video cameras and cameras in China have developed rapidly in recent years. The output and consumption of lithium cells have therefore increased remarkably. The demand for DMC in the lithium cell sector will grow considerably.
   Pesticide sector: Consumption of DMC in the pesticide sector is still relatively small today. Nevertheless, China is a big pesticide producer. With the accelerated restructuring of the pesticide sector and the prohibition of the use of five high-toxicity organophosphorus pesticides including methamidophos, the market share of substitute pesticides made from DMC, such as carbofuran and indoxacarb, will increase further. The demand for DMC in the pesticide sector will continue to grow.

Sectors worth development

(1) Use as additive in gasoline and diesel fuel

Research on the use of DMC as an additive in gasoline and diesel has been robust in recent years. Usually 10% of MTBE (methyl tert-butyl ether) is added, while only 3.3% DMC is needed. (The oxygen content of a DMC molecule is 53% whereas the oxygen content of an MTBE molecule is 17%.) With the intensive research on its use as an additive for gasoline and diesel fuel, the constant improvement of its production technology and further reduction of its production costs, DMC will likely enter the gasoline/diesel additive market with huge potential.

(2) Use in the synthesis of isocyanates

Isocyanates include MDI (diphenylmethane diisocyanate), HDI (hexamethylene diisocyanate) and TDI (toluene diisocyanate). These products can produce polyurethane foam plastics, construction insulation materials, coatings, elastomers, adhesives, insecticides and herbicides. Chengdu Organic Chemicals Company Ltd. of Chinese Academy of Sciences has already completed bench tests on the preparation of MDI and HDI through the DMC ammonolysis process and achieved good results. Pilot tests will be conducted in collaboration with chemical producers.