A device for manufacturing dimethyl carbonate including a reaction section and a separation section is provided. The reaction section includes a first distillation column, a methanol supply device, a carbon dioxide supply device, a dehydrating agent supply device, and a side reactor. The methanol supply device is connected to the first distillation column. The carbon dioxide supply device is connected to the first distillation column. The dehydrating agent supply device is connected to the first distillation column. A feed nozzle of the side reactor is connected to a gas outlet of a top of the first distillation column. A discharge nozzle of the side reactor is connected to a recycle nozzle of the first distillation column. A catalyst is disposed in the side reactor. The separation section includes a second distillation column. The second distillation column is connected to a liquid outlet of a bottom of the first distillation column.

The invention relates to a process for preparing a specific hydroxy compound by means of decarboxylation of a specific carboxylic acid compound or a salt of said carboxylic acid compound, to a method for preparing a diaryl carbonate, a bisphenol or a polycarbonate, a diaryl carbonate or bisphenol, a polycarbonate, and to a method for adjusting the isotope ratio of C14 to C12 in a polymer. A specific solvent is used during decarboxylation.

The invention relates to a process for preparing a specific hydroxy compound by means of decarboxylation of a specific carboxylic acid compound or a salt of said carboxylic acid compound, to a method for preparing a diaryl carbonate, a bisphenol or a polycarbonate, a diaryl carbonate or bisphenol, a polycarbonate, and to a method for adjusting the isotope ratio of C14 to C12 in a polymer. A specific solvent is used during decarboxylation.

The invention relates to a process for preparing a specific hydroxy compound by means of decarboxylation of a specific carboxylic acid compound or a salt of said carboxylic acid compound, to a method for preparing a diaryl carbonate, a bisphenol or a polycarbonate, a diaryl carbonate or bisphenol, a polycarbonate, and to a method for adjusting the isotope ratio of C14 to C12 in a polymer. A specific solvent is used during decarboxylation.

The invention relates to a process for preparing a specific hydroxy compound by means of decarboxylation of a specific carboxylic acid compound or a salt of said carboxylic acid compound, to a method for preparing a diaryl carbonate, a bisphenol or a polycarbonate, a diaryl carbonate or bisphenol, a polycarbonate, and to a method for adjusting the isotope ratio of C14 to C12 in a polymer. A specific solvent is used during decarboxylation.

Provided is a dialkyl carbonate production method that enables a dialkyl carbonate to be produced in a simple manner and in a short reaction time and enables easy processing of by-products. This dialkyl carbonate production method involves generation reaction of a carbonate ester through reaction between carbon dioxide and an alcohol represented by formula (1), wherein the generation reaction of a carbonate ester is performed in the presence of a carbodiimide compound represented by formula (2) (R.sub.1-R.sub.3 in the formula are as described in the description of the present application).

[Chemical formula 1]

R.sub.1—OH  (1)

[Chemical formula 2]

R.sub.2—N═C═N—R.sub.3  (2)

Provided is a dialkyl carbonate production method that enables a dialkyl carbonate to be produced in a simple manner and in a short reaction time and enables easy processing of by-products. This dialkyl carbonate production method involves generation reaction of a carbonate ester through reaction between carbon dioxide and an alcohol represented by formula (1), wherein the generation reaction of a carbonate ester is performed in the presence of a carbodiimide compound represented by formula (2) (R.sub.1-R.sub.3 in the formula are as described in the description of the present application).

[Chemical formula 1]

R.sub.1—OH  (1)

[Chemical formula 2]

R.sub.2—N═C═N—R.sub.3  (2)

Provided is a dialkyl carbonate production method that enables a dialkyl carbonate to be produced in a simple manner and in a short reaction time and enables easy processing of by-products. This dialkyl carbonate production method involves generation reaction of a carbonate ester through reaction between carbon dioxide and an alcohol represented by formula (1), wherein the generation reaction of a carbonate ester is performed in the presence of a carbodiimide compound represented by formula (2) (R.sub.1-R.sub.3 in the formula are as described in the description of the present application).

[Chemical formula 1]

R.sub.1—OH  (1)

[Chemical formula 2]

R.sub.2—N═C═N—R.sub.3  (2)

Provided is a method for regenerating an aromatic amide compound into a corresponding aromatic nitrile compound, the method realizing a dehydration reaction of providing a target compound selectively at a high yield, with generation of a by-product being suppressed. Also provided is a method for producing an aromatic nitrile compound that decreases the number of steps of the dehydration reaction and significantly improves the reaction speed even at a pressure close to normal pressure. In addition, the above-described production method is applied to a carbonate ester production method to provide a method for producing a carbonate ester efficiently. The above-described methods are realized by a method for producing an aromatic nitrile compound including a dehydration reaction of dehydrating an aromatic amide compound, in which the dehydration reaction uses, as a solvent, any of 1,2-dimethoxybenzene, 1,3-dimethoxybenzene and 1,3,5-trimethoxybenzene.

The present invention provides a method for producing an aromatic nitrile compound, the method comprising a dehydration reaction wherein a desired compound can be selectively obtained with high yield while suppressing the generation of byproducts during the regeneration of an aromatic amide compound into the corresponding aromatic nitrile compound. In addition, the present invention realizes a method for efficiently producing a carbonate ester by applying the abovementioned production method to a method for producing a carbonate ester. The above are achieved by means of a method for producing an aromatic nitrile compound involving a dehydration reaction wherein an aromatic amide compound is dehydrated, the method having a contact step for bringing the aromatic amide compound into contact with a catalyst in a gas phase during the dehydration reaction.