Organic compounds -- part of the class 532-570 series – Organic compounds – Carbonate esters
Patent
1998-02-03
1999-02-23
Ambrose, Michael G.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbonate esters
C07C 6806
Patent
active
058746056
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a process for preparing an aromatic carbonate ester by transesterification of an aromatic carboxylate with an aliphatic carbonate ester and/or aromatic.aliphatic carbonate ester using a multistage reactive distillation equipment. The aromatic carbonate esters are industrially useful compounds.
BACKGROUND ART
As a process for preparing an aromatic carbonate ester by, for example, transesterification of an aliphatic carbonate ester with an aromatic hydroxy compound or aromatic carboxylate has been known. In particular, as a process for preparing diphenyl carbonate as a kind of aromatic carbonate esters, many methods have been proposed. For example, U.S. Pat. No. 4,533,504 discloses a process for preparing diphenyl carbonate by reacting dimethyl carbonate as a kind of aliphatic carbonate esters with phenyl acetate as a kind of aromatic carboxylates.
Moreover, Japanese Patent Publication (Tokukaihei) No. 3-291257 discloses a process for preparing a diphenyl carbonate as a target product using a continuous multistage distillation column (reactive distillation equipment) in which a reaction of dimethyl carbonate with phenol as a kind of aromatic hydroxy compounds is carried out to generate methyl phenyl carbonate, and then methyl phenyl carbonate is disproportionated to produce diphenyl carbonate.
In the method disclosed in U.S. Pat. No. 4,533,504, the conversion of dimethyl carbonate is as high as 70 mole percent or more. However, since this method is a batch system, high productivity cannot be achieved. Therefore, diphenyl carbonate can not be prepared efficiently by this method.
The method disclosed in Japanese Patent Publication (Tokukaihei) No. 3-291257 also suffers from low productivity because the conversion of dimethyl carbonate is around 1.6 mole percent to 24 mole percent. Additionally, in this method, since diphenyl carbonate is obtained by disproportionation of methyl phenyl carbonate, many processing steps need to be carried out to prepare the diphenyl carbonate. Thus, the diphenyl carbonate cannot be prepared efficiently by this method.
Therefore, there is a great demand for a process that ensures efficient preparation of diphenyl carbonate, i.e., aromatic carbonate ester. Namely, in order to solve the above-mentioned problems associated with the conventional methods, it is an object of the present invention to provide a process for continuously and efficiently preparing aromatic carbonate esters.
DISCLOSURE OF THE INVENTION
In order to solve the problems associated with the conventional methods, the present inventors eagerly studied the process for preparing aromatic carbonate esters. The inventors found as a result of study that the reaction efficiency of the transesterification of an aromatic carboxylate with an aliphatic carbonate ester and/or aromatic.aliphatic carbonate ester using a multistage reactive distillation equipment can be improved by continuously feeding a raw material including these compounds to the first stage of the equipment and continuously feeding to the second stage lower than the first stage an aliphatic carbonate ester whose boiling point is lower than that of a reactant liquid that is present in the second stage. In short, the inventors completed the present invention based on such a discovery that the aromatic carbonate ester can be continuously and efficiently prepared by feeding the aliphatic carbonate ester whose boiling point is lower than the boiling point of the reactant liquid that is present in the second stage continuously to the second stage lower than the first stage to which the raw material is fed.
Namely, in order to solve the above-mentioned problems, a process for preparing aromatic carbonate esters of the present invention is a process for preparing an aromatic carbonate ester by transesterification of an aromatic carboxylate with an aliphatic carbonate ester and/or aromatic.aliphatic carbonate ester, and characterized by using a multistage reactive distillation equipment having a first stage and a
REFERENCES:
patent: 4533504 (1985-08-01), Bolon et al.
patent: 5210268 (1993-05-01), Fukuoka et al.
patent: 5543546 (1996-08-01), Tsuneki et al.
Moriya Atusi
Onda Yoshiyuki
Tsuneki Hideaki
Wakayama Hiroki
Watanabe Ken'ichi
Ambrose Michael G.
Nippon Shokubai Co. , Ltd.
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