Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2001-08-12
2003-12-09
Rotman, Alan L. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C560S209000, C560S218000
Reexamination Certificate
active
06660881
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Technical Field
The present invention relates to a process for producing a (meth)acrylic ester which uses an ion-exchange resin as a catalyst.
B. Background Art
An ion-exchange resin which has been so far used as a catalyst when a (meth)acrylic ester is produced from raw materials of an alcohol and an acid is often marketed in a moistened condition with water. When the ion-exchange resin is used in a reaction, water is usually projected into a reaction vessel in advance so as to prevent the damage of the resin. Then, the water is drained outside the reaction vessel after the ion-exchange resin is projected, so that the ion-exchange resin is packed in the reaction vessel.
However, an esterification reaction is an equilibrium reaction. Therefore, if water exists in a system of reaction, a conversion rate is low and a reaction is difficult to proceed. Therefore, the problem arises that the more water content the ion-exchange resin used as a catalyst in the esterification reaction contains, the more greatly a reaction yield falls. Accordingly, it is desired that the water content contained in the ion-exchange resin should be decreased as much as possible, before the ion-exchange resin is used in the esterification reaction.
Furthermore, a reaction to produce a hydroxyalkyl (meth)acrylate among the (meth)acrylic ester from raw materials of the alkylene oxide and the acid is not an equilibrium reaction. However, in the case where the ion-exchange resin is used as a catalyst of the esterification reaction, the more water the ion-exchange resin contains, the more greatly the concentration of raw materials in a system of reaction and a reaction yield falls. Accordingly, it is desired that the water content contained in the ion-exchange resin should be decreased as much as possible.
The decrease of water content contained in the ion-exchange resin has so far been performed by methods such as azeotropic dehydration by use of a solvent, warming under reduced pressure, and washing by use of a polar solvent.
However, if the effective utilization of a distillate as formed on the occasion of azeotropic dehydration is taken into account, it is preferred that such a solvent as forms a binary liquid phase with water is used, and that an oil phase separated from a water phase is recycled as a reflux. However, in the case where azeotropic distillation is performed with a stirred tank apparatus by use of an water-insoluble solvent, the ion-exchange resin tends to aggregate in the solvent, and in its turn an operational problem, such as a difficulty in stirring, tends to arise.
SUMMARY OF THE INVENTION
A. Objects of the Invention
An object of the present invention is to provide a process for producing a (meth)acrylic ester which enables to obtain a (meth)acrylic ester in an excellent reaction yield.
B. Disclosure of the Invention
The present inventors studied and studied with encouragement to themselves and great efforts to solve the above problems. As a result, the inventors have completed the present invention by finding out that in the case of the production of the (meth)acrylic ester, prior to performing an esterification reaction step, it becomes possible to improve a yield remarkably in the esterification reaction by performing a dehydration step of removing water impregnated in an ion-exchange resin by use of an alcohol and/or an acid of raw materials in an esterification reaction and/or the resulting ester in the esterification reaction.
Furthermore, the inventors have completed the present invention by finding out that in the case of the production of the (meth)acrylic ester from raw materials of the alkylene oxide and the acid, it becomes possible to prevent the aggregation of the ion-exchange resin on the occasion of dehydration by azeotropic removal of water as contained in the ion-exchange resin by using a solvent which not only forms a binary liquid phase with water but also has a constant solubility to water, and that it becomes possible to decrease effectively the water content as contained in the ion-exchange resin.
That is to say, the primary process for producing a (meth)acrylic ester according to the present invention is a process which uses an alcohol and an acid as raw materials and an ion-exchange resin as a catalyst, and the process is characterized by comprising a dehydration step and an esterification step, wherein the esterification reaction step follows the dehydration step in which water impregnated in the ion-exchange resin is removed by using as a dehydrating solvent at least one member selected from the group consisting of the alcohol, the acid, and the resulting ester.
Furthermore, the second process for producing a (meth)acrylic ester according to the present invention is a process which uses an alkylene oxide and an acid as raw materials and an ion-exchange resin as a catalyst, and the process is characterized by comprising a dehydration step and an esterification step, wherein the esterification reaction step follows the dehydration step in which water impregnated in the ion-exchange resin is azeotropically dehydrated by distilling a solvent (A) together with the ion-exchange resin, wherein the solvent (A) exhibits a solubility of not less than 0.05 g per 100 g of water at 20° C., and forms a binary liquid phase with water.
Furthermore, the third process for producing a (meth)acrylic ester according to the present invention is a process which uses an alkylene oxide and an acid as raw materials and an ion-exchange resin as a catalyst, and the process is characterized by comprising a dehydration step and an esterification step, wherein the esterification reaction step follows the dehydration step in which water impregnated in the ion-exchange resin is azeotropically dehydrated by distilling a solution of a mixture of solvents (B) and (C) together with the ion-exchange resin, wherein the solvent (B) is soluble in water in arbitrary ratio and wherein the solvent (C) exhibits a solubility of less than 0.05 g per 100 g of water at 20° C. and forms a binary liquid phase with water.
These and other objects and the advantages of the present invention will be more fully apparent for the following detailed disclosure.
DETAILED DESCRIPTION OF THE INVENTION
Modes for carrying out the present invention are hereinafter described in detail.
In a process for producing a (meth)acrylic ester of the present invention, prior to an esterification reaction step, it is important to perform a dehydration step to remove water impregnated in an ion-exchange resin used as a catalyst. In the dehydration step, it becomes possible to improve a yield in the esterification reaction following the dehydration step by decreasing the water content in the ion-exchange resin sufficiently in advance in the dehydration step.
In the present invention, the aforementioned dehydration step is a step of removing water impregnated in the ion-exchange resin by using as a dehydrating solvent at least one member selected from the group consisting of an alcohol, an acid (raw materials of the esterification reaction), and the resulting ester in the esterification reaction. In the case where the dehydrating solvent remains in the ion-exchange resin after dehydration, it becomes possible to improve a reaction yield effectively without preventing the esterification reaction by using as dehydrating solvents raw materials of the esterification reaction, or the resulting ester in the esterification reaction.
In the aforementioned dehydration step, a method of removing water impregnated in the ion-exchange resin is not especially limited except for using the aforementioned dehydrating solvent. For example, a method of washing the ion-exchange resin with the aforementioned solvent, a method of removing water by performing distillation after adding the aforementioned solvent to the ion-exchange resin or such is preferably enumerated.
In the case of the method of washing the ion-exchange resin with the aforementioned solvent, more specifically in the case of washing by use of a fixed-bed react
Kajihara Tetsuya
Matsumoto Hajime
Munechika Fumio
Nakahara Sei
Shingai Yasuhiro
Haugen Law Firm PLLP
Nippon Shokubai Co. , Ltd.
Oh Taylor V
Rotman Alan L.
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