Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-01-08
2004-04-06
Killos, Paul J. (Department: 1623)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S002000, C524S003000, C524S004000, C560S224000
Reexamination Certificate
active
06716896
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for the production of an esterified product and an apparatus therefor. More particularly, the invention relates to a method for efficiently producing a (meth)acrylic ester (occasionally referred to briefly as “esterified product” in the present specification) of high quality by the esterification reaction of an alcohol with (meth)acrylic acid, and to an apparatus therefor. Especially, in quantity production of an esterified product on a commercial scale by continuous operation of an apparatus for production, this invention relates to a method for the production of the esterified product excelling in production efficiency, and the apparatus therefor.
2. Description of the Related Art
A varying alkoxy polyalkylene glycol mono(meth)acrylic ester type monomer component which forms a raw material for a polymer component to be used in cement dispersants, and pigment dispersants for calcium carbonate, carbon black, ink, and other pigments, scale removers, dispersants for a slurry of gypsum and water, dispersants for CWM, thickeners, and etc. can be obtained by subjecting an alkoxy polyalkylene glycol and (meth)acrylic acid to the esterification reaction. Since this esterification reaction by-produces water simultaneously, the reaction which is equilibratory in nature ceases to proceed in the direction of forming the esterified product unless the water formed by the reaction is removed from the reaction system (namely when the water formed by the reaction is suffered to accumulate therein).
As found in Controls 1 and 2 cited in JP-A-09-328,346, for example, the synthesis of a varying alkoxy polyalkylene glycol mono(meth) acrylic ester type monomer component which forms a raw material for a polymer component to be used in a cement dispersant resorts to a principle of providing a water separator for accomplishing the separation of the water formed by the reaction. More specifically, this publication discloses a method for synthesizing an expected esterified product by using a reaction vessel designed for the synthesis of an alkoxy polyalkylene glycol mono(meth)acrylic ester type monomer by the esterification reaction and adapted to permit separation of the water formed by the reaction by providing a reaction vessel (a separable flask) with a thermometer, a stirrer, and a water separator, performing the esterification reaction by placing methacrylic acid, methoxy polyethylene glycol (an average addition mol number of oxyethylene groups of 10 mols), sulfuric acid (Control 1) or paratoluene sulfonic acid (Control 2) as an acid catalyst, phenothiazine as a polymerization inhibitor, and cyclohexane as a solvent in the reaction vessel and meanwhile stirring and heating the reactants and consequently effecting distillation of a cyclohexane-water azeotropic mixture under normal pressure, removing the water formed by the reaction with the water separator, and refluxing the cyclohexane, and after the completion of the esterification reaction, expelling the used cyclohexane by distillation.
No technical tasks other than the idea of providing a water separator for separating and removing the water formed by the reaction during the course of the esterification reaction or the idea of expelling a dehydrating solvent by distillation after the completion of the esterification reaction using a dehydrating solvent as disclosed in the patent publication mentioned above has heretofore been reported to the literature.
SUMMARY OF THE INVENTION
An object of this invention, therefore, is to solve the technical problems of the prior art and to provide a method for the production of an esterified product and an apparatus therefor.
Another object of this invention is to provide a method for the production of an esterified product which prevents the occurrence of a gel-like substance during the separation and removal of the water formed by the reaction by causing an antigelling agent to act on the distillate and consequently permits efficient production of the esterified product of high quality, and an apparatus therefor.
Still another object of this invention is to provide a method for the production of an esterified product which prevents the occurrence of a gel-like substance during the expulsion of a dehydrating solvent by distillation after the esterification reaction and consequently permits efficient production of the esterified product of high quality, and an apparatus therefor.
Further object of this invention is to provide a method for the production of an esterified product by the esterification reaction of an alcohol and (meth)acrylic acid which always prevents effectively the occurrence of a gel-like substance on a path for expulsion by distillation by causing a sufficient amount of an anti-gelling agent-containing solution to act on the distillate and consequently permits efficient and inexpensive formation of the esterified product of high quality, and an apparatus therefor.
Still further object of this invention is to provide a method for the production of an esterified product which, when a dehydrating solvent is used in the production of the esterified product, represses growth of an amount of a residue of condensate returned to a reaction tank besides fulfilling the object mentioned above as small as possible by causing a sufficient amount of an antigelling agent-containing solution to act on the distillate and consequently permits efficient and inexpensive formation of the esterified product of high quality, and an apparatus therefor.
The prevent inventors, while continuing a diligent study with a view to attaining efficient formation of an esterified product of high quality, have found that a gel-like substance is formed during the condensation of a distillate arising from the esterification reaction (an azeotropic mixture of a solvent with water formed by the reaction) and that this gel-like substance gives birth to numerous technical problems as evinced by the fact that a part of this gel-like substance, on being refluxed in conjunction with the solvent, persists as an extraneous substance in the reaction tank, mingles into a finished product (for example, a cement dispersant, a pigment dispersant, a scale remover, a dispersant for a slurry of gypsum and water, a dispersant for CWM, and a thickener), and forms a cause for degrading the performance and quality of the product, that the gel-like substance, when the esterified product is produced in a large quantity on a commercial scale, cumulatively adheres to the inner wall of a piping and a device (for example, a condenser), i.e. means for condensing, separating, and removing water formed by the reaction, and eventually induces possible degradation of the heat-exchange efficiency during the condensation, that the deposit of the gel-like substance, when the operation is repeated or continued with a view to attaining quantity production on a commercial scale, impairs the flow of the fluid (mainly the liquid resulting from the condensation) in the condenser and the piping, possibly induces clogging thereof, and consequently compels the operation to be periodically suspended for permitting removal of the gel-like substance from the interior of the condenser and the piping by washing.
The present inventors have further found that the expulsion of the dehydrating solvent to be effected in the form of an azeotropic mixture with added water after the completion of the esterification reaction by the use of a dehydrating solvent reflux system fulfilling the purpose of separating and removing the water formed by the reaction forms a gel-like substance besides the gel-like substance formed during the esterification reaction and that the distillate containing this gel-like substance, when suffered to reach the step of polymerization and eventually mingle into the finished product (for example, a cement dispersant, a pigment dispersant, a scale remover, a dispersant for a slurry of gypsum and water, a dispersant for CWM, and a thickener), degrades the performance and
Hirata Tsuyoshi
Tanaka Hiromichi
Yuasa Tsutomu
Killos Paul J.
Mathews, Collins Shepherd & McKay, P.A.
Nippon Shokubai Co. , Ltd.
Oh Taylor Victor
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