The present application addresses the problem of providing a method for efficiently producing a dialkyl carbonate. The problem can be solved by a method for producing a dialkyl carbonate by reacting urea and at least one alkyl carbamate with an aliphatic alcohol in the presence of a catalyst, the method including introducing a gas for expelling ammonia generated by the reaction into a reactor in which the reaction is being conducted and discharging the ammonia generated in the reactor and the introduced gas, the reaction being conducted so that the gas introduction satisfies relationship (1).
52.0<((A+B)×22400+L×M/17.03×22400)/L<91.0  (1)
(In formula (1), A, B, L, and M are as defined above.)

The present application addresses the problem of providing a method for efficiently producing a dialkyl carbonate. The problem can be solved by a method for producing a dialkyl carbonate by reacting urea and at least one alkyl carbamate with an aliphatic alcohol in the presence of a catalyst, the method including introducing a gas for expelling ammonia generated by the reaction into a reactor in which the reaction is being conducted and discharging the ammonia generated in the reactor and the introduced gas, the reaction being conducted so that the gas introduction satisfies relationship (1).
52.0<((A+B)×22400+L×M/17.03×22400)/L<91.0  (1)
(In formula (1), A, B, L, and M are as defined above.)

The present application addresses the problem of providing a method for efficiently producing a dialkyl carbonate. The problem can be solved by a method for producing a dialkyl carbonate by reacting urea and at least one alkyl carbamate with an aliphatic alcohol in the presence of a catalyst, the method including introducing a gas for expelling ammonia generated by the reaction into a reactor in which the reaction is being conducted and discharging the ammonia generated in the reactor and the introduced gas, the reaction being conducted so that the gas introduction satisfies relationship (1).
52.0<((A+B)×22400+L×M/17.03×22400)/L<91.0  (1)
(In formula (1), A, B, L, and M are as defined above.)

A dialkyl carbonate is prepared by reacting urea with an alkyl monohydric alcohol at 70 C. to 150 C. under normal pressure or reduced pressure. The reaction is conducted for 6 h to 30 h under stirring and reflux, with one or more of magnesium, calcium, aluminum, chromium, manganese, iron, cobalt, nickel, copper and zinc as a primary catalyst and one or more compounds including an electron-donating nitrogen, phosphonis, oxygen or sulfur atom as a catalyst promoter. The dialkyl carbonate is prepared under low reaction temperature and normal pressure or reduced pressure, with high selectivity and high yield. With simple operations, high safety and low cost for the process, the method has prominent industrial application prospects.

A dialkyl carbonate is prepared by reacting urea with an alkyl monohydric alcohol at 70 C. to 150 C. under normal pressure or reduced pressure. The reaction is conducted for 6 h to 30 h under stirring and reflux, with one or more of magnesium, calcium, aluminum, chromium, manganese, iron, cobalt, nickel, copper and zinc as a primary catalyst and one or more compounds including an electron-donating nitrogen, phosphonis, oxygen or sulfur atom as a catalyst promoter. The dialkyl carbonate is prepared under low reaction temperature and normal pressure or reduced pressure, with high selectivity and high yield. With simple operations, high safety and low cost for the process, the method has prominent industrial application prospects.

A dialkyl carbonate is prepared by reacting urea with an alkyl monohydric alcohol at 70 C. to 150 C. under normal pressure or reduced pressure. The reaction is conducted for 6 h to 30 h under stirring and reflux, with one or more of magnesium, calcium, aluminum, chromium, manganese, iron, cobalt, nickel, copper and zinc as a primary catalyst and one or more compounds including an electron-donating nitrogen, phosphonis, oxygen or sulfur atom as a catalyst promoter. The dialkyl carbonate is prepared under low reaction temperature and normal pressure or reduced pressure, with high selectivity and high yield. With simple operations, high safety and low cost for the process, the method has prominent industrial application prospects.

A dialkyl carbonate is prepared by reacting urea with an alkyl monohydric alcohol at 70 C. to 150 C. under normal pressure or reduced pressure. The reaction is conducted for 6 h to 30 h under stirring and reflux, with one or more of magnesium, calcium, aluminum, chromium, manganese, iron, cobalt, nickel, copper and zinc as a primary catalyst and one or more compounds including an electron-donating nitrogen, phosphonis, oxygen or sulfur atom as a catalyst promoter. The dialkyl carbonate is prepared under low reaction temperature and normal pressure or reduced pressure, with high selectivity and high yield. With simple operations, high safety and low cost for the process, the method has prominent industrial application prospects.

A dialkyl carbonate is prepared by reacting urea with an alkyl monohydric alcohol at 70 C. to 150 C. under normal pressure or reduced pressure. The reaction is conducted for 6 h to 30 h under stirring and reflux, with one or more of magnesium, calcium, aluminum, chromium, manganese, iron, cobalt, nickel, copper and zinc as a primary catalyst and one or more compounds including an electron-donating nitrogen, phosphonis, oxygen or sulfur atom as a catalyst promoter. The dialkyl carbonate is prepared under low reaction temperature and normal pressure or reduced pressure, with high selectivity and high yield. With simple operations, high safety and low cost for the process, the method has prominent industrial application prospects.

A process for preparing a silver-containing catalyst for the selective oxidation of ethylene to ethylene oxide including the steps of: (a) providing a multimodal support, (b) preparing an impregnation solution comprising a silver component, (c) impregnating, at least once, the multimodal support of step (a) with the silver-containing impregnation solution of step (b) to form an impregnated support; (d) subjecting the impregnated multimodal support from step (c) to a removal means, such as a centrifuge, at least once, for a time sufficient to remove impregnated silver impregnation solution from the multimodal support and to control the amount of silver in the pores of the multimodal support by selectively removing impregnated silver impregnation solution from a set of larger pores in the multimodal support; (e) roasting, at least once, the multimodal support after the step (d); (f) optionally, repeating the impregnation step (c), (g) optionally, repeating the centrifugation step (d), and (h) optionally, repeating the calcination step (e).

A process for preparing a silver-containing catalyst for the selective oxidation of ethylene to ethylene oxide including the steps of: (a) providing a multimodal support, (b) preparing an impregnation solution comprising a silver component, (c) impregnating, at least once, the multimodal support of step (a) with the silver-containing impregnation solution of step (b) to form an impregnated support; (d) subjecting the impregnated multimodal support from step (c) to a removal means, such as a centrifuge, at least once, for a time sufficient to remove impregnated silver impregnation solution from the multimodal support and to control the amount of silver in the pores of the multimodal support by selectively removing impregnated silver impregnation solution from a set of larger pores in the multimodal support; (e) roasting, at least once, the multimodal support after the step (d); (f) optionally, repeating the impregnation step (c), (g) optionally, repeating the centrifugation step (d), and (h) optionally, repeating the calcination step (e).