Industrial processes dimethyl carbonate

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]. 

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. 

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)] ... 

In order to produce methyl isocyanate in good safety s conditions, Bayer A.-G. has developed an industrial process based on the reaction of diphenyl carbonate with N,N -dimethyl urea at high temperature according to scheme 158 (Ref. 212). 

Different variations of the Enichem process have been described that may show some improvements in selectivity and efficiency of the catalyst system, but they generally seem to be less attractive from the economic point of view and none of them has been realized until now. For example, since 1986 the Japanese company Daicel especially has applied for numerous patents on modifications of the Enichem process, in which dimethyl carbonate is prepared in the presence of catalyst systems that contain copper and palladium salts and additional modifiers, e. g., quinoid compounds and quatemery phosphonium halides [40-48]. Although Daicel has announced several times the constmction of an industrial plant for the production of dimethyl carbonate, all investment plans now seem to be put aside. The separation of the reaction product from the complicated catalyst system as well as the complete recycling of the palladium compounds, which is a necessary requirement for any economic process design, seem not to be solved sufficiently. 

Linear dialkyl carbonates and in particular dimethyl carbonate (DMC) are used in many industrial applications in the industry [70, 71], The usual way of synthesizing carbonates involves reactive Ci agents such as phosgene or CO [72]. Although these methods are from an economical viewpoint more than profitable, the development of an environmentally friendly industrial process involving CO2 as a Cl-building block attracts an ever-increasing interest. 

Development of environmentally benign industrial processes utilizing CO2, which is a cheap and safe Ci resource as well as a nontoxic reaction medium, has received much interest. One of the attractive reactions is the synthesis of dimethyl carbonate (DMC) from CO2 and methanol. The reaction is reversible and can be expressed by eqn. (3) ... 

Oxidative carbonylation of methanol to dimethyl carbonate. Dimethyl carbonate (DMC) is made industrially by the phosgenation of methanol, but it can also be produced without the use of phosgene by the oxidative carbonylation of methanol. Enichem has commercialized a process for dimethyl carbonate based on oxidative carbonylation [25]. 

Cyclic carbonate synthesis from epoxide and CO2 is one of the few industrial processes that use CO2 as a feedstock. The reaction proceeds in the presence of catalysts that are typically metal halides or tetraalkylammonium halides. The products (e.g. ethylene carbonate, which is an important intermediate of dimethyl carbonate) are utilized for polycarbonate synthesis via a non-phosgene, melt polymerization process. 

Reactions that require phosgene are dangerous, and dimethyl carbonate (DMC) 33 is the most promising phosgene substitute. Current industrial processes for DMC synthesis are oxidative carbonylation of methanol and transesterification of ethylene carbonate with methanol. Hence, the direct reaction of CO2 and methanol (Scheme 58) is regarded as an attractive, next-generation process, but the limitation... 

Industrial processes for dialkyl oxalate and dimethyl carbonate from CO, alcohol and oxygen catalyzed by Pd have been developed by Ube Industries in Japan [2]. 

The standard composition of an electrolyte in LlBs is a mixture of cycUc carbonates (such as ethylene carbonate (EC) and propylene carbonate (PC)) and chain carbonates (such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC abbreviated as MEC below), and diethyl carbonate (DEC)), to which about 1 mol/L of a lithium salt (such as lithium hexafluorophosphate (LiPF )) is added. Ube Industries, Ltd. discovered that if small amounts of impurities exist in the electrolyte, decomposition current generated from the impurities begins to flow, which leads to the formation of undesirable thick SET This spurred the development of a pioneering high-grade purification process for the base electrolyte in 1997 [16]. High purity is a key feature of functional electrolytes developed by Ube Industries, Ltd. and enables production of transparent and chemically stable electrolytes, in contrast to the conventional electrolytes which were less stable and brown owing to its low purity (Fig. 3.1). 

Daicel Chemical Industries, Ltd., has patented a process for reacting diamines, such as isophorone diamine (IPDA), with dimethyl carbonate. The condensation is accomplished in the presence of an alkaline catalyst, such as methanolic sodium methylate at 70 °C, to produce the diurethane. Treatment of the diurethane with hydrogenated terphenyl containing manganese acetate at 230 °C in vacuo produces isophorone diisocyanate by thermal decomposition. This non-phosgene process has a reported product yield of 93% of IPDI containing 1% isophorone monoisocyanate. 

Carbonylation of alcohol group, methanol to dimethyl carbonate (DMC) and dimethyl oxalate (DMO), phenol to diphenyl carbonate (DPC), is very important chemical process in the current chemical industry. Dialkoxyl carbonate is key material for phosgene free process. The electrocarbonylation has great advantages to compare with a conventional catalytic carbonylation with O2. A particular advantage of electrocarbonylation is to be able to suppress CO2 formation by oxidation of CO because oxidizing power can be controlled as finely as one millivolt and there is no oxygen. 

Dimethyl carbonate (DMG) is a Uquid equivalent of phosgene (mp 2-4 °G bp 90 °C). Reported toxicity and ecotoxicity data lead to the classification of DMC as both a non-toxic and environmentally benign chemical [116, 117] (see also Chapter 3). The areas in which DMC serves, or can serve, as an actual or potential phosgene substitute correspond to the main areas of phosgene industrial applications, e.g. the production of aromatic polycarbonate and isocyanates, leading the production of these important chemicals out of the chlorine cycle [117]. However, one major aspect has to be considered in this context, i.e. the production of DMC itself, since the traditional process for DMC production has involved phosgene as a raw material [118]. 

Keller, N. Rebmann, G. Keller, V. Catalysts, Mechanisms and Industrial Processes for the Dimethyl Carbonate Synthesis. J. Mol. Catal. A Chem. 2010, 317,1-18. 

Sulfides find use (Table 3) in the refinery and petrochemical industries. " Some refiners use dimethyl sulfide as a sulfiding agent to convert the metal oxide hydrotreating catalysts to their sulfide form. In ethylene manufacture, ethane or other hydrocarbon liquid like naphtha is reacted at high temperatures with steam. The process would make an unacceptable amount of coke and produce too much carbon... 

Combustion processes constitute an important class of reactions, and the enthalpy changes associated with them give important information for operators of industrial plant as well as for internal combustion engineers. As an example, consider the hydrocarbon 3,3-dimethyl pentane, C7Hi6, a component of high-octane petrol. For combustion to carbon dioxide and liquid water ... 

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