The manufacture method of diaryl oxalate

Abstract

Disclosed is a process for preparing a diaryl oxalate which comprises the step of transesterifying a dialkyl oxalate or / and an alkylaryl oxalate with an aryl alcohol in the presence of a tetra(aryloxy)titanium as a catalyst, wherein the tetra(aryloxy)titanium is fed into a reaction system of the transesterification as an aryl alcohol solution of the tetra(aryloxy)titanium which is prepared by reacting a tetraalkoxy titanium and an excess amount of the aryl alcohol and removing a by-producing alkyl alcohol.

Description

technical field

[0001] The present invention relates to a method for producing a diaryl oxalate by transesterifying a dialkyl oxalate or / and an alkylaryl oxalate with an aryl alcohol, and the like. Background technique

[0002] Diaryl oxalate can be used as a raw material of diaryl carbonate which has been widely used as a monomer in the production of polycarbonate by the melt method by decarbonylation, and is a compound attracting attention in recent years. Diaryl oxalate can be produced by transesterifying dialkyl oxalate and aryl alcohol, and dialkyl oxalate used at this time can be produced from carbon monoxide and alkyl nitrite.

[0003] A series of methods for producing diaryl carbonate from carbon monoxide and alkyl nitrite via dialkyl oxalate and diaryl oxalate have been proposed (see Patent Document 1).

[0004] In addition, a method for producing diaryl oxalate has been proposed, which is characterized in that dialkyl oxalate and aryl alcohol are subjected to a tr...

Examples

Embodiment

[0192] The present invention is illustrated in detail by way of examples below. However, the present invention is not limited to the following examples at all.

Synthetic example 1

[0194] Synthesis of tetraphenoxytitanium

[0195] 300 ml of phenol was charged at the bottom of a flat-bottomed flask with an inner diameter of 32 mm and an Oldershaw type reactive distillation column (hereinafter referred to as "reactive distillation column for catalyst synthesis") having a volume of 1 L, and heated with an oil bath to raise the temperature. After the temperature distribution in the reactive distillation tower for catalyst synthesis was stabilized while maintaining the total reflux state, phenol was fed at a flow rate of 342.4g / h, and titanium tetraisopropoxide (TIPT) was fed at a flow rate of 21.6g / h . The ratio of the number of moles of phenol fed to the number of moles of Ti atoms in the TIPT (phenol / Ti) was 48. Keeping the reflux ratio at 5 the distillate from the top was withdrawn. In addition, it was continuously withdrawn from the bottom of the reaction distillation column for catalyst synthesis so that the liquid level at the bottom was maintained a...

Synthetic example 2～4

[0200] Synthesis of tetraphenoxytitanium

[0201] The same experiment as in Synthesis Example 1 was performed by changing some of the conditions shown in Table 1, and the results are shown in Table 1.

[0202] In addition, in the reaction solution of Synthesis Example 4, TPT was partially separated.

technical field

[0001] The present invention relates to a method for producing a diaryl oxalate by transesterifying a dialkyl oxalate or / and an alkylaryl oxalate with an aryl alcohol, and the like. Background technique

[0002] Diaryl oxalate can be used as a raw material of diaryl carbonate which has been widely used as a monomer in the production of polycarbonate by the melt method by decarbonylation, and is a compound attracting attention in recent years. Diaryl oxalate can be produced by transesterifying dialkyl oxalate and aryl alcohol, and dialkyl oxalate used at this time can be produced from carbon monoxide and alkyl nitrite.

[0003] A series of methods for producing diaryl carbonate from carbon monoxide and alkyl nitrite via dialkyl oxalate and diaryl oxalate have been proposed (see Patent Document 1).

[0004] In addition, a method for producing diaryl oxalate has been proposed, which is characterized in that dialkyl oxalate and aryl alcohol are subjected to a tr...

Examples

Embodiment

[0192] The present invention is illustrated in detail by way of examples below. However, the present invention is not limited to the following examples at all.

Synthetic example 1

[0194] Synthesis of tetraphenoxytitanium

[0195] 300 ml of phenol was charged at the bottom of a flat-bottomed flask with an inner diameter of 32 mm and an Oldershaw type reactive distillation column (hereinafter referred to as "reactive distillation column for catalyst synthesis") having a volume of 1 L, and heated with an oil bath to raise the temperature. After the temperature distribution in the reactive distillation tower for catalyst synthesis was stabilized while maintaining the total reflux state, phenol was fed at a flow rate of 342.4g / h, and titanium tetraisopropoxide (TIPT) was fed at a flow rate of 21.6g / h . The ratio of the number of moles of phenol fed to the number of moles of Ti atoms in the TIPT (phenol / Ti) was 48. Keeping the reflux ratio at 5 the distillate from the top was withdrawn. In addition, it was continuously withdrawn from the bottom of the reaction distillation column for catalyst synthesis so that the liquid level at the bottom was maintained a...

Synthetic example 2～4

[0200] Synthesis of tetraphenoxytitanium

[0201] The same experiment as in Synthesis Example 1 was performed by changing some of the conditions shown in Table 1, and the results are shown in Table 1.

[0202] In addition, in the reaction solution of Synthesis Example 4, TPT was partially separated.

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