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Method for the continuous production of unsaturated carboxylic acid anhydrides

An unsaturated, carboxylic acid anhydride technology, applied in the direction of carboxylic acid anhydride preparation, chemical instruments and methods, carboxylate preparation, etc., can solve the problem that by-products cannot be completely removed

Active Publication Date: 2009-05-06
EVONIK OPERATIONS GMBH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Forms many by-products that cannot be completely removed

Method used

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  • Method for the continuous production of unsaturated carboxylic acid anhydrides
  • Method for the continuous production of unsaturated carboxylic acid anhydrides

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Embodiment Construction

[0059] The preparation of ketene (3) is carried out according to a conventional method. A detailed description of the preparation of ketene is contained, for example, in H. Held, A. Rengstl and D. Mayer, Acetic anhydride and mixed fatty acid anhydrides, Ullmann's Encyclopedia of Industrial Chemistry, 6th edition, Wiley VCH, Weinheim, 2003, pp. 184-185 Page.

[0060] The following reaction of ketene with (meth)acrylic acid (=(M)AS) in reaction zone (1) is likewise carried out according to conventional methods (see also H. Held et al., p. 185ff.). At this point the crude anhydride mixture (4) is fed into a further reaction zone (2). The temperature of reactant can be adjusted through heat exchanger (5) during adding.

[0061] Reactor (2) is preferably a flow tube reactor containing a fixed bed catalyst. As fixed-bed catalysts, preference is given to using acidic ion exchangers.

[0062] The reactor waste stream (6) is fed into a rectification column (7), preferably in the lo...

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Abstract

The invention relates to a method for the continuous production of unsaturated carboxylic acid anhydrides of general formula (I): R-C(O)-O-C(O)-R (I), wherein R is an unsaturated organic group with 2 to 12 C atoms, by reaction of a ketene with an unsaturated carboxylic acid of general formula (II): R-COOH (II), wherein R is defined as above, in an apparatus which has a reaction zone (1) for the reaction of a ketene with an unsaturated carboxylic acid of general formula (II), and a reaction zone (2) for the subsequent reaction of the crude anhydride mixture and a rectification column with an upper, a middle and a lower zone, in the sump of which an inert boiling oil is present.

Description

technical field [0001] The present invention describes a process for the continuous preparation of unsaturated carboxylic anhydrides, in particular the reaction of unsaturated carboxylic acids with ketenes. Background technique [0002] DE-A-3510035 describes a process for the continuous preparation of unsaturated carboxylic anhydrides by acid-catalyzed anhydride exchange reaction of acetic anhydride with unsaturated carboxylic acids in the middle part of a distillation column. To achieve complete reaction, acetic anhydride is used in excess of 0.1 to 0.5 Mol / Mol carboxylic acid, then a mixture of acetic acid and acetic anhydride is produced at the top of the column, ie no pure acetic acid is obtained. [0003] In addition, products are formed which are contaminated with catalysts which have to be removed only in further process steps. [0004] In US-A-4,857,239 a process is described for the preparation of methacrylic anhydride in which the molar ratio of methacrylic acid ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/04
CPCC07C51/56C07C51/567C07C57/04C07C51/00C07C67/04C07C69/757
Inventor D·布罗尔H·西格特
Owner EVONIK OPERATIONS GMBH
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