Dimethyl carbonate methanol

Comelli, F. and Francesconi, R. Isothermal vapor-liquid equilibria measurements, excess molar enthalpies, and excess molar volumes of dimethyl carbonate + methanol. + ethanol, and propan-l -ol at 313.15 K. J. Chem. Eng. Data, 42(4) 705-709, 1997. 

Lummus Technology Dimethyl Carbonate Methanol, carbon monoxide and oxygen Produces DMC via oxidative carbonylatlon of methanol, avoiding the use of phosgene 3 1995... 

An analogue of the transesterification process has also been demonstrated, in which the diacetate of BPA is transesterified with dimethyl carbonate, producing polycarbonate and methyl acetate (33). Removal of the methyl acetate from the equihbrium drives the reaction to completion. Methanol carbonylation, transesterification using phenol to diphenyl carbonate, and polymerization using BPA is commercially viable. The GE plant is the first to produce polycarbonate via a solventiess and phosgene-free process. 

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 ... 

Dimethyl sulfate (16 g) is added to a mixture of dimethyl carbonate (400 g) and deuterium oxide (1(X) g) in a 1 liter flask. Two reflux condensers and a drying tube are attached in series (initial rapid evolution of carbon dioxide may entrain some liquid), and the reaction mixture is heated under reflux for 72 hr. The methanol-OD is distilled directly from the reaction flask through a 30 cm Vigreux column. Redistillation from a small amount of sodium yields 275 g of pure methanol-OD bp 66-66.5° isotopic purity, 98.6%. ... 

Dimethyl carbonate (DMC) is a colorless liquid with a pleasant odor. It is soluble in most organic solvents but insoluble in water. The classical synthesis of DMC is the reaction of methanol with phosgene. Because phosgene is toxic, a non-phosgene-route may be preferred. The new route reacts methanol with urea over a tin catalyst. However, the yield is low. Using electron donor solvents such as trimethylene glycol dimethyl ether and continually distilling off the product increases the yield. ... 

Ethylene carbonate is a reactive chemical. It reacts smoothly with methanol and produces ethylene glycol in addition to dimethyl carbonate ... 

The alkali-catalysed methanolysis of poly(2,2-bis(4-hydroxyphenyljpropane carbonate) (PC) in a mixture of methanol (MeOH) and toluene or dioxane was studied. The treatment of PC in meOH, with a catalytic amount of sodium hydroxide, yielded only 7% bisphenol A. Using a mixed solvent of MeOH and toluene completely depolymerised PC to give 96% free bisphenol A in solid form and dimethyl carbonate in solution. The eharaeteristies of the catalysis are discussed together with the pseudo-first rate kinetics of the depolymerisation. The reaetion eonditions were investigated to facilitate the reeyeling of PC plasties. 17 refs. 

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)... 

Today most dimethyl carbonate is made by methanol carbonylation (Equation 3.2) using a copper chloride catalyst with a very long life. This process produces pure dimethyl carbonate, which is not now classified as harmful, and water as a by-product. 

Synthesis of dimethyl carbonate by transesterification of ethylene carbonate and methanol using quaternary ammonium salt catalysts... 

Selva, M. Perosa, A. (2008) Green Chemistry Metrics A Comparative Evaluation of Dimethyl Carbonate, Methyl Iodide, Dimethyl Sulfate and Methanol as Methylating Agents. Green Chemistry, 10, 457-464. 

A potential green route to dimethyltin carbonate can be based on the reaction of methanol and carbon dioxide, catalyzed by dimethyltin dimethoxide. In supercritical CO2 as solvent, the dimethoxide reacts to give the monocarbonate, which at 180 °C and 300 atm pressure gives dimethyl carbonate, probably by an intramolecular rearrangement, with regeneration of the dimethoxide (Equation (139)).385,386... 

The oxidative carbonylation of alcohols and phenols to carbonates can be catalyzed by palladium or copper species [154-213]. This reaction is of particular practical importance, since it can be developed into an industrial process for the phosgene-free synthesis of dimethyl carbonate (DMC) and diphenyl carbonate (DPC), which are important industrial intermediates for the production of polycarbonates. Moreover, DMC can be used as an eco-friendly methylation and carbonylation agent [214,215]. The industrial production of DMC by oxidative carbonylation of methanol has been achieved by Enichem [216] and Ube [217]. 

Aminabhavi, T.M. and Banerjee, K. Density, viscosity, refractive index, and speed of sound in binary mixtures of dimethyl carbonate with methanol, chloroform, carbon tetrachloride, cyclohexane, and dichloromethane in the temperature interval (298.15-308.15) K, / Chem. Eng. Data, 43(6) 1096-1101,1998a. 

The teirperature dependencies of the chemical shift values for both Cl and C4 were determined in four different solvents (water, dimethyl sulfoxide, methanol and dioxane) and are shown in Figures 8 and 9. The resonance for Cl at 298 C varied from 101.6 ppm in D2O to 104.0 ppm in methanol. The resonance for C4 at the same temperature varied from 75.3 ppm in dimethyl sulfoxide to 78.3 ppm in methanol. The most pronounced tenperature dependence is observed in water and dioxane, where Cl and C4 signals varied from 101.4 ppm to 101.9 ppm (Cl, water, 278-358 K) and from 75.7 ppm to 76.5 ppm (C4, dioxane, 288-360 K), respectively. Thus, both tenperature and solvent dependence of C shifts indicate different conformational behavior of the molecule at various physico-chemico conditions. This feature is manifested even more clearly by the dependencies of the three-bond proton-carbon J and J coupling constants (< ) - Hl -Cl -04-C4 and f = H4-C4-04-C1 ) which are plotted against tenperature in Figures 10 and 11. 

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. 

The oxidative carbonylation of methanol to dimethyl carbonate has found small industrial application (26-27). The reaction can be carried out in two steps following Equation 10 and 11 or also in one step. 

Me have studied the Co-I-PPh catalyzed reductive carbonylation of methanol, dimethyl ketalsf dimethyl carbonate and methyl esters ( 10 JL5 >2 ) 0 goal was to achieve high acetaldehyde... 

The reaction of dimethyl carbonate with synthesis gas requires a cobalt-iodide catalyst and operating conditions of 180 C and 4000 psig. The acetaldehyde rate approaches 30 M/hr with selectivities greater than 85%. The productivities are much better than with methanol however, recycle of the CO and methanol back to dimethyl carbonate is very difficult ... 

The main obstacle to percntaneous penetration of water and xenobiotics is the onter-most membrane of the epidermis. This is called the stratum comeum. All entry of substances through the stratum comeum occurs by passive diffusion across several cell layers. The locus of entry varies, depending on the chemical properties of xenobiotics. Polar substances are believed to penetrate cell membranes through the protein filaments nonpolar ones enter through the hpid matrix. Hydration of the stratnm comenm increases its permeability for polar substances. Electrolytes enter mainly in a nonionized form, and thus the pH of the solution applied to the skin affects permeabUity. Many hpophdic substances, such as carbon tetrachloride and organophosphate insecticides, readily penetrate the stratum comeum. Pretreatment of the skin with solvents, snch as dimethyl sulfoxide, methanol, ethanol, hexane, acetone, and, in particular, a mixture of chloroform and methanol, increases permeability of the skin (Loomis, 1978). 

Daicel Chemical Industries in Japan patented a promising phosgene-free process involving the reaction of an aliphatic diamine with dimethyl carbonate (DMC) to produce carbamate esters, which are then thermally converted to the corresponding aliphatic diisocyanates [38] (Scheme 5.4). It is noteworthy that this process could be a total phosgene-free process since the reactant, DMC, can be made directly from methanol and carbon dioxide (or urea) and eliminates the use of phosgene [39]. 

Dimethyl Carbonate. An industrial process to manufacture dimethyl carbonate through the oxidative carbonylation of methanol catalyzed by cuprous chloride has been developed and commercialized by EniChem.197,198 The reaction occurs in two steps. Cupric methoxy chloride is formed in the first oxidation step [Eq. (7.21)], which is then reduced to yield dimethyl carbonate and regenerate cuprous chloride [Eq. (7.22)] ... 

---