Abstract: The present invention relates to a process for preparing (meth)acrylates, which comprises the transesterification of an alcohol with a low-boiling ester of (meth)acrylic acid in the presence of catalysts, with the alcohol liberated from the low-boiling ester of (meth)acrylic acid being separated off by distillation, characterized in that the molar ratio of low-boiling ester of (meth)acrylic acid to starting alcohol present in the reaction mixture is increased during the reaction by addition of low-boiling ester of (meth)acrylic acid. The process of the invention makes a particularly inexpensive preparation of (meth)acrylates having a very high purity possible.

Abstract: The present invention relates to a process for preparing butanediol dimethacrylates, which comprises the transesterification of butanediol with an ester of methacrylic acid in the presence of catalysts, wherein a combination comprising at least one lithium compound and at least one calcium compound is used as catalyst, at least one of the compounds of lithium and/or of calcium is an oxide, a hydroxide, an alkoxide having from 1 to 4 carbon atoms or a carboxylate having from 1 to 4 carbon atoms and at least part of the reaction is carried out in the presence of an effective amount of water. The process of the invention makes a particularly inexpensive preparation of butanediol dimethacrylates having a very high purity possible.

Abstract: The present invention relates to a process for preparation of pure methacrylic acid, at least comprising the process steps: a) gas phase oxidation of a C4 compound to obtain a methacrylic acid-comprising gas phase, b) condensation of the methacrylic acid-comprising gas phase to obtain an aqueous methacrylic acid solution, c) separation of at least a part of the methacrylic acid from the aqueous methacrylic acid solution to obtain at least one crude methacrylic acid-comprising product; d) separation of at least a part of the methacrylic acid from the at least one crude methacrylic acid-comprising product by means of a thermal separation process to obtain a pure methacrylic acid.

Abstract: The present invention relates to a process for preparing (meth)acrylates, which comprises the transesterification of an alcohol with a low-boiling ester of (meth)acrylic acid in the presence of catalysts, with the alcohol liberated from the low-boiling ester of (meth)acrylic acid being separated off by distillation, characterized in that the molar ratio of low-boiling ester of (meth)acrylic acid to starting alcohol present in the reaction mixture is increased during the reaction by addition of low-boiling ester of (meth)acrylic acid. The process of the invention makes a particularly inexpensive preparation of (meth)acrylates having a very high purity possible.

Abstract: The present invention relates to a process for preparing butanediol dimethacrylates, which comprises the transesterification of butanediol with an ester of methacrylic acid in the presence of catalysts, wherein a combination comprising at least one lithium compound and at least one calcium compound is used as catalyst, at least one of the compounds of lithium and/or of calcium is an oxide, a hydroxide, an alkoxide having from 1 to 4 carbon atoms or a carboxylate having from 1 to 4 carbon atoms and at least part of the reaction is carried out in the presence of an effective amount of water. The process of the invention makes a particularly inexpensive preparation of butanediol dimethacrylates having a very high purity possible.