A method of producing a diaryl carbonate, comprising: performing both a transesterification reaction and a disproportionation reaction within a reactive distillation column by introducing a feed stream comprising a dialkyl carbonate to the reactive distillation column at a point above a reboiler, and introducing an aromatic hydroxyl compound to the reactive distillation column; producing a diaryl carbonate, within the reactive distillation column; and withdrawing a bottom product stream comprising the diaryl carbonate from the reactive distillation column, preferably the diaryl carbonate has a purity of greater than or equal to 99.97 wt %.

A compound represented by a formula [1D] as shown below (wherein R.sup.1A, R.sup.1B, R.sup.2A, R.sup.2B, R.sup.3A and R.sup.3B represent a hydrogen atom, an optionally substituted C.sub.1-6 alkyl group, and the like) is useful as an intermediate for producing a thionucleoside, and the production method of the present invention is useful as a method for producing a thionucleoside. ##STR00001##

A compound represented by a formula [1D] as shown below (wherein R.sup.1A, R.sup.1B, R.sup.2A, R.sup.2B, R.sup.3A and R.sup.3B represent a hydrogen atom, an optionally substituted C.sub.1-6 alkyl group, and the like) is useful as an intermediate for producing a thionucleoside, and the production method of the present invention is useful as a method for producing a thionucleoside. ##STR00001##

A compound represented by a formula [1D] as shown below (wherein R.sup.1A, R.sup.1B, R.sup.2A, R.sup.2B, R.sup.3A and R.sup.3B represent a hydrogen atom, an optionally substituted C.sub.1-6 alkyl group, and the like) is useful as an intermediate for producing a thionucleoside, and the production method of the present invention is useful as a method for producing a thionucleoside. ##STR00001##

The present disclosure discloses an energy-saving method for preparing electronic-grade carbonate, including the following steps that: industrial-grade dimethyl carbonate and anhydrous ethanol enter a reaction process after being preheated by a preheater, and are subjected to an esterification reaction under the action of a catalyst to obtain a mixture containing dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate, and an azeotrope of dimethyl carbonate and methanol; the above-mentioned mixture enters a recovery process of dimethyl carbonate to recover unreacted dimethyl carbonate; a mixture of ethyl methyl carbonate and diethyl carbonate then enters a crude separation process to obtain crude ethyl methyl carbonate and crude diethyl carbonate; and the crude ethyl methyl carbonate is subjected to a refining process of ethyl methyl carbonate to obtain electronic-grade ethyl methyl carbonate, and the crude diethyl carbonate is subjected to a refining process of diethyl carbonate to obtain electronic-grade diethyl carbonate.

The present disclosure discloses an energy-saving method for preparing electronic-grade carbonate, including the following steps that: industrial-grade dimethyl carbonate and anhydrous ethanol enter a reaction process after being preheated by a preheater, and are subjected to an esterification reaction under the action of a catalyst to obtain a mixture containing dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate, and an azeotrope of dimethyl carbonate and methanol; the above-mentioned mixture enters a recovery process of dimethyl carbonate to recover unreacted dimethyl carbonate; a mixture of ethyl methyl carbonate and diethyl carbonate then enters a crude separation process to obtain crude ethyl methyl carbonate and crude diethyl carbonate; and the crude ethyl methyl carbonate is subjected to a refining process of ethyl methyl carbonate to obtain electronic-grade ethyl methyl carbonate, and the crude diethyl carbonate is subjected to a refining process of diethyl carbonate to obtain electronic-grade diethyl carbonate.

Provided is a method for preparing an asymmetric linear carbonate, the method comprising: subjecting two kinds of different symmetric linear carbonates to a transesterification reaction in the presence of a metal alkoxide catalyst to prepare an asymmetric linear carbonate, wherein the metal of the metal alkoxide is at least one selected from the group consisting of aluminum (Al), magnesium (Mg), germanium (Ge), gallium (Ga), cobalt (Co), calcium (Ca), hafnium (Hf), iron (Fe), nickel (Ni), niobium (Nb), molybdenum (Mo), lanthanum (La), rhenium (Re), scandium (Sc), silicon (Si), tantalum (Ta), tungsten (W), yttrium (Y), zirconium (Zr) and vanadium (V). Also provided is an asymmetric linear carbonate including the metal alkoxide catalyst.

Provided is a method for preparing an asymmetric linear carbonate, the method comprising: subjecting two kinds of different symmetric linear carbonates to a transesterification reaction in the presence of a metal alkoxide catalyst to prepare an asymmetric linear carbonate, wherein the metal of the metal alkoxide is at least one selected from the group consisting of aluminum (Al), magnesium (Mg), germanium (Ge), gallium (Ga), cobalt (Co), calcium (Ca), hafnium (Hf), iron (Fe), nickel (Ni), niobium (Nb), molybdenum (Mo), lanthanum (La), rhenium (Re), scandium (Sc), silicon (Si), tantalum (Ta), tungsten (W), yttrium (Y), zirconium (Zr) and vanadium (V). Also provided is an asymmetric linear carbonate including the metal alkoxide catalyst.

Provided is a method for preparing an asymmetric linear carbonate, the method comprising: subjecting two kinds of different symmetric linear carbonates to a transesterification reaction in the presence of a metal alkoxide catalyst to prepare an asymmetric linear carbonate, wherein the metal of the metal alkoxide is at least one selected from the group consisting of aluminum (Al), magnesium (Mg), germanium (Ge), gallium (Ga), cobalt (Co), calcium (Ca), hafnium (Hf), iron (Fe), nickel (Ni), niobium (Nb), molybdenum (Mo), lanthanum (La), rhenium (Re), scandium (Sc), silicon (Si), tantalum (Ta), tungsten (W), yttrium (Y), zirconium (Zr) and vanadium (V). Also provided is an asymmetric linear carbonate including the metal alkoxide catalyst.

This invention relates to aprocess for the preparation of glycerolcarbonate from the reaction of glycerol and a dialkyl-carbonate, for example dimethyl carbonate, or a cyclic alkylene carbonate. More specifically, the invention relates to a process where the synthesis of glycerolcarbonate is conducted in the presence of a homogeneous transesterificationcatalyst and involves the partial reaction of a glycerol reactant stream and a dialkyl carbonateor cyclic alkylene carbonate reactant stream and an intermediate step of alcohol by-product separation before further reaction in order to improve glycerol conversion and glycerol carbonate selectivity and yield.