Methanol dimethyl carbonate production from

Dimethyl carbonate [616-38-6] and dimethyl oxalate [553-90-2] are both obtained from carbon monoxide, oxygen, and methanol at 363 K and 10 MPa (100 atm) or less. The choice of catalyst is critical cuprous chloride (66) gives the carbonate (eq. 20) a palladium chloride—copper chloride mixture (67,68) gives the oxalate, (eq. 21). Anhydrous conditions should be maintained by removing product water to minimize the formation of by-product carbon dioxide. 

Oxygenates and Chemicals A whole host of oxygenated products, i.e., fuels, fuel additives, and chemicals, can be produced from synthesis gas. These include such produc ts as methanol, ethylene, isobutanol, dimethyl ether, dimethyl carbonate, and many other hydrocarbons and oxyhydrocarbons. Typical oxygenate-producing reactions are ... 

Both new catalysts and new processes need to be developed for a complete exploitation of the potential of CO2 use [41]. The key motivation to producing chemicals from CO2 is that CO2 can lead to totally new polymeric materials and also new routes to existing chemical intermediates and products could be more efficient and economical than current methods. As a case in point, the conventional method for methanol production is based on fossil feedstock and the production of dimethyl carbonate (DMC) involves the use of toxic phosgene or CO. A proposed alternative production process involves the use of CO2 as a raw material (Figure 7.1)... 

This method of transesterification is of high technical interest. Particularly the reaction of bisphenol A with diphenyl carbonate is a preferred phosgene-free process because biphenyl carbonate can be obtained directly from phenol and dimethyl carbonate.The latter is an industrial product made from CO and methanol. 

To a 2 liter Hoke pressure cylinder are added 20.0 gm (0.21 mole) of aniline, 13.8 gm (0.43 mole) of sulfur, 100 ml of methanol, and 82 ml of an 8.75 M (0.73 mole) aqueous dimethylamine. The cylinder is pressurized with 100 psig of carbon monoxide, and then heated for 2 hr at 100°C. The cylinder is then vented and the contents removed from the cylinder by washing with hot methanol. The combined product and methanol washings were filtered hot and evaporated to dryness from the methanol. The urea product is recrystallized from 400 ml of water to give 27.8 gm (79%) of l,l-dimethyl-3-phenylurea, m.p. 130°-133°C. 

Diphenyl carbonate from dimethyl carbonate and phenol Dibutyl phthalate from butanol and phthalic acid Ethyl acetate from ethanol and butyl acetate Recovery of acetic acid and methanol from methyl acetate by-product of vinyl acetate production Nylon 6,6 prepolymer from adipic acid and hexamethylenediamine MTBE from isobutene and methanol TAME from pentenes and methanol Separation of close boiling 3- and 4-picoline by complexation with organic acids Separation of close-boiling meta and para xylenes by formation of tert-butyl meta-xyxlene Cumene from propylene and benzene General process for the alkylation of aromatics with olefins Production of specific higher and lower alkenes from butenes... 

The concept of co-carbonylation of methanol/methyl acetate mixtures was first introduced by BASF in the early 1950s, but the reaction chemistry was not fully developed to commercial realization [75]. Not until the mid-1980s, after the development of carbonylation processes to produce acetic acid and acetic anhydride, were co-carbonylation processes patented using homogeneous rhodium/iodine catalyst systems (Table 2) [2, 56]. The basic process concept is to manufacture acetic acid and acetic anhydride from methanol and carbon monoxide as the only raw materials and to generate methyl acetate within the process. Similiarly, the suitability of dimethyl ether as a raw material for the generation of the anhydride equivalent in addition to or as a substitute for methyl acetate was revealed by Hoechst [76]. To produce a small fraction of acetic acid besides acetic anhydride as the main product, the carbonylation of methyl acetate could be conducted with small amounts of water or methanol. This variant, first demonstrated by Hoechst [56], is practiced by Eastman Kodak [2]. 

Ethylene carbonate has the advantage of a high boiling point (bp) (236 °C at 101 MPa) and it is possible to eliminate the resulting ethylene glycol (bp = 197.3 °C at 101 MPa) without major elimination of ethylene carbonate from the reaction system. Dimethyl carbonate has the advantage of elimination of a much lower boiling point product methanol (bp = 64.7 °C at 101 MPa). 

Application The Polimeri/Lummus process is a phosgene-free route for the production of diphenyl carbonate (DPC)—a polycarbonate intermediate—from dimethyl carbonate (DMC) and phenol. The Polimeri/Lummus DPC process has no environmental or corrosion problems, and the byproduct methanol can be recycled back to the DMC process. 

In almost all of the work reported so far on electrochemical reactions in supercritical fluids, the emphasis has not been on preparative organic synthesis. One of the principal questions tackled has been whether the Stokes-Einstein relationship between diffusion and viscosity continues to be valid for an SCF, and the conclusion is that it probably is. In synthesis, the only significant study is the production of dimethyl carbonate from CO and methanol using sc CO2 as a cosolvent with methanol (Dombro et al., 1988). The use of sc CO2 in place of water enabled the reaction to be carried out near the critical point, that is, at a lower temperature. Tetrabutylammonium bromide (TBAB) in a concentration of 1-5% was used as an electrolyte and bromide source. The reactions occurring at the two electrodes are... 

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