Abstract: An alkyl nitrite can be produced on an industrial scale with a high efficiency and with a low yield of by-products by the process wherein nitrogen oxide-containing feed gas is brought into an alkyl alcohol liquid in a distillation column reactor while circulating a liquid fraction, produced in the reactor and containing the alkyl alcohol, through a circulation path including a lower section of the reactor and a cooler to remove the reaction heat vigorously generated in the reactor, and while controlling the weight ratio of the circulating liquid fraction to the total alkyl alcohol fed into the reactor to 50:1 to 200:1, the molar ratio of the total alkyl alcohol fed to the reactor and contained in the circulating liquid fraction to nitrogen oxide in the feed gas to 20:1 to 150:1, and the content of the alkyl alcohol in the liquid fraction to 15 to 60% by weight; and the resultant gas fraction containing the target alkyl nitrite is collected from the reactor.

Abstract: The present invention relates to a process for producing a diaryl oxalate, characterized in that an alkylaryl oxalate is subjected to a disproportionation reaction in the presence of a disproportionation catalyst, thereby to produce a diaryl oxalate while removing a by-product comprising a dialkyl oxalate.The production process of the present invention is advantageous in that the kinds of the by-products are fewer than that in conventional production process for diaryl oxalate, and thus can be practically utilized in industry, and the diaryl oxalates such as diphenyl oxalate, produced by the production process of the present invention are very important industrial materials for producing chemical products such as carbamates.

Abstract: A diaryl carbonate is produced by decarbonylating a diaryl oxalate, which can be prepared by transesterification of a dialkyl oxalate with a hydroxyaryl compound, in the presence of a catalyst, while removing the resultant carbon monoxide as a by-product, and then optionally refined by an evaporation and/or distillation, and then the resultant diaryl carbonate is condensation-polymerized with a polyhydroxyl compound, while recovering a resultant hydroxyaryl compound from the reaction system, to produce a polycarbonate.

Abstract: A process for preparing a diaryl carbonate from a diaryl oxalate in a liquid phase by decarbonylation is conducted by the steps of:1) performing a decarbonylation reaction of a diaryl oxalate in the presence of an organic phosphorus compound catalyst to give a reaction mixture of a diaryl carbonate and the organic phosphorus compound catalyst;2) recovering the diaryl carbonate from the reaction mixture; and3) performing a decarbonylation reaction of a diaryl oxalate in the presence of the reaction mixture from which the diaryl carbonate has been recovered and to which a halogen atom-containing compound is added, to give a reaction mixture of a diaryl carbonate and the organic phosphorus compound catalyst.

Abstract: A catalyst composed of an organic phosphorus compound having a trivalent or pentavalent phosphorus atom and at least one carbon-phosphorus bonding or a combination of the organic phosphorus compound and a halogen atom-containing compound is effective for decarbonylation, that is, for releasing carbon monoxide from a compound containing a moiety of --CO--CO--O-- in its molecular structure.

Abstract: An ester compound, for example, carbonic acid ester or succinic acid ester, is produced by catalytically reacting, in gas phase, carbon monoxide with a nitrous acid ester and optionally an olefin in the presence of a catalyst and in the presence of a chlorine-containing substance, bringing the reaction product-containing mixed gas into contact with a solid catalyst such as activated carbon or inorganic oxide to reduce the content of the chlorine-containing substance, cool-condensing the resultant mixed gas, and collecting the target ester compound from the condensed liquid.

Abstract: A high purity diaryl carbonate is produced with a high efficiency by reacting carbon monoxide with an alkyl nitrite and/or an alkyl alcohol; reacting the resultant dialkyl oxalate with a hydroxyaryl compound, for example, phenol; decarbonylating the resultant diaryl oxalate to produce a diaryl carbonate and carbon monoxide; and collecting the diaryl carbonate from the decarbonylation reaction product mixture, the carbon monoxide produced in the decabonylation step being optionally reused for the production of the dialkyl oxalate.

Abstract: A diaryl carbonate with a high degree of purity is produced at a high yield by (A) subjecting (a) a diaryl oxalate and a phenol compound or (b) an alkylaryl oxalate to transesterification reaction in one or two stages in the presence of a catalyst to prepare a diaryl oxalate, while removing a by-product from the reaction system; (B) collecting the diaryl oxalate from the resultant reaction product mixture of the step (A); (C) subjecting the diaryl oxalate to a decarbonylation reaction, preferably in the presence of a phosphorous compound-containing catalyst, to convert the diaryl oxalate to a corresponding diaryl carbonate, while removing a reaction by-product comprising carbon monoxide from the reaction system; and (D) collecting the diaryl carbonate from the reaction product mixture of the step (C).

Abstract: A diaryl carbonate with a high degree of purity is produced at a high yield by (A) subjecting (a) a diaryl oxalate and a phenol compound or (b) an alkylaryl oxalate to transesterification reaction in one or two stages in the presence of a catalyst to prepare a diaryl oxalate, while removing a by-product from the reaction system; (B) collecting the diaryl oxalate from the resultant reaction product mixture of the step (A); (C) subjecting the diaryl oxalate to a decarbonylation reaction, preferably in the presence of a phosphorous compound-containing catalyst, to convert the diaryl oxalate to a corresponding diaryl carbonate, while removing a reaction by-product comprising carbon monoxide from the reaction system; and (D) collecting the diaryl carbonate from the reaction product mixture of the step (C).

Abstract: A novel crystalline adduct of diphenyl oxalate and phenol in a molar ratio of 1:2 and having a high purity is produced by melting a mixture containing diphenyl oxalate and phenol at a temperature of 100.degree. C. or more; cooling the melt to a temperature of less than 100.degree. C. to allow a resultant adduct of diphenyl oxalate and phenol in a molar ratio of 1:2 to crystallize and deposit from the melt; and collecting the crystalline adduct. Diphenyl oxalate with a high purity is produced by melting the crystalline adduct to dissociate it into diphenyl oxalate and phenol, and evaporating away the dissociated phenol from the melt to collect the dissociated diphenyl oxalate.

Abstract: A diaryl carbonate is prepared at a high yield and a high selectivity by heating a diaryl oxalate in the presence of an organic phosphorous compound to release carbon monoxide therefrom. A halogen atom-containing compound can be employed in combination with the organic phosphorous compound.

Abstract: Dimethyl carbonate ((CH.sub.3 O).sub.2 CO) is continuously produced by a catalytic reaction (first step) of CO with CH.sub.3 NO.sub.2, with a significantly reduced loss of CH.sub.3 ONO by the process including a second step wherein (CH.sub.3 O).sub.2 CO in a reaction product gas of the first step is absorbed by dimethyl oxalate while contacting the resultant liquid fraction with CO to recover CH.sub.3 ONO, a third step wherein CH.sub.3 ONO is regenerated from NO in the condensed gas fraction produced in the second step and molecular oxygen and CH.sub.3 OH introduced into the third step, the resultant regenerated gas fraction being recycled and reused as a feed gas for the first step, and a fourth step wherein (CH.sub.3 O).sub.2 CO contained in the liquid fraction of the second step is collected.

Abstract: A process for producing dimethyl carbonate is carried out by a first step of catalytically reacting carbon monoxide with methyl nitrite to produce dimethyl carbonate; a second step of absorbing dimethyl carbonate contained in a gas fraction withdrawn from the first step by dimethyl oxalate; a third step of regenerating methyl nitrite by contacting nitrogen monoxide contained in a gas fraction withdrawn from the second step with a molecular oxygen-containing gas and methyl alcohol; a fourth step of collecting dimethyl carbonate by distilling a liquid fraction withdrawn from the second step; and a fifth step of producing and recovering methyl nitrite from a purge gas consisting of a minor portion of a gas fraction withdrawn from one of the second step and the third step by bringing the purge gas together with an ammonia-oxidation product gas into contact with methyl alcohol in a methyl nitrite-recovering column, to thereby produce and recover methyl nitrite contained in the recovering column with a high efficie

Abstract: A process for producing dimethyl carbonate is carried out by a first step of catalytically reacting carbon monoxide with methyl nitrite to produce dimethyl carbonate; a second step of absorbing dimethyl carbonate contained in a gas fraction withdrawn from the first step by dimethyl oxalate; a third step of regenerating methyl nitrite by contacting nitrogen monoxide contained in a gas fraction withdrawn from the second step with a molecular oxygen-containing gas and methyl alcohol; a fourth step of collecting dimethyl carbonate by distilling a liquid fraction withdrawn from the second step; and a fifth step of recovering methyl nitrite from a purge gas consisting of a portion of a regenerated gas fraction withdrawn from the third step by absorbing methyl nitrite in the purge gas by methyl alcohol to provide a methyl nitrite-containing liquid fraction and a nitrogen monoxide-containing gas fraction and bringing the gas fraction into contact with a molecular oxygen and methyl alcohol, to convert nitrogen monoxid

Abstract: Disclosed is a process for preparing carbamates comprising reacting carbonic acid diester with ammonia or amines in a liquid phase in the presence of at least 1 mole % of water based on carbonic acid diester.

Abstract: Disclosed is a process for preparing carbonic diester comprising the formation of carbonic diester by the vapor phase catalytic reaction of an alkyl nitrite and carbon monoxide in the presence of a solid catalyst, wherein platinum group metal ion in the solid catalyst is exchanged on an ion exchange zeolite carrier.

Abstract: An N-hydroxycarbamate compound of the formula ROCONHOH in which R is C.sub.1-8 alkyl, C.sub.3-12 cycloalkyl, aryl or aralkyl group, is produced by reacting a carbonic acid diester of the formula ROCOOR in which R is as defined above, with hydroxylamine in the presence of a basic substance, for example, an alkali metal hydroxide or alkoxide.

Abstract: Disclosed a process for purifying dimethyl carbonate which comprises distillating a mixture of dimethyl carbonate and methanol in the presence of dimethyl oxalate to separate and remove methanol.

Abstract: The present invention provides a method of preparing sodium formyl acetone using acetone, methyl formate and sodium methoxide as raw materials. A mixture consisting of an acetone and a methyl formate is supplied to a methanol solution of sodium methoxide, or an acetone and a methyl formate are separately supplied simultaneously to the methanol solution of sodium methoxide. The resultant mixture is sufficiently stirred over a predetermined period of time so as to carry out the reaction to form sodium formyl acetone. Also provided is a method of preparing 4,4-dimethoxy-2-butanone. In this method, the reaction mixture obtained in the reaction to form sodium formyl acetone is directly charged into a reaction vessel simultaneously with sulfuric acid to neutralize and acetalize sodium formyl acetone contained in the reaction mixture so as to obtain 4,4-dimethoxy-2-butanone.

Abstract: Disclosed is a continuous process for preparing dimethyl carbonate which comprises:a first step of introducing a gas containing carbon monoxide and methyl nitrite into a reactor filled with a solid catalyst to obtain a reaction product containing dimethyl carbonate;a second step of separating the reaction product to a non-condensed gas and a solution containing dimethyl carbonate by adding dimethyl oxalate;a third step of introducing the non-condensed gas into a regenerating column to contact it with a molecular state oxygen-containing gas and methanol whereby regenerating nitrogen monoxide to methyl nitrite, so as to contain 2 to 7% by volume of nitrogen monoxide in a non-absorbed gas at an outlet of the column, which in turn is introduced in the reactor of the first step;a fourth step of extracting, distilling and separating dimethyl carbonate from the solution by further adding dimethyl oxalate to remove methanol; anda fifth step of distilling and separating dimethyl carbonate from a mixed solution to remo