Process for preparing acrylic acid and methacrylic acid

    公开(公告)号:CZ2000885A3

    公开(公告)日:2000-08-16

    申请号:CZ2000885

    申请日:1998-09-09

    Applicant: BASF AG

    Abstract: A process for preparing acrylic acid or methacrylic acid comprises preparing a gaseous product mixture having essentially the composition of a reaction mixture of the catalytic gas phase oxidation of C3-/C4-alkanes, -alkenes, -alkanols and/or -alkanals and/or precursors thereof to form acrylic acid or methacrylic acid. The product is removed from the gaseous product mixture by a process comprising the following steps:(a) condensing said gaseous product mixture,(b) crystallizing acrylic acid or methacrylic acid from the solution obtained in step (a),(c) removing the resulting crystals from the mother liquor, and(d) recycling at least a portion of said mother liquor from step (c) into step (a).

    SEPARATION OF A C.SUB.4-HYDROCARBON MIXTURE ESSENTIALLY CONTAINING N-BUTENES AND BUTANES

    公开(公告)号:CA1222258A

    公开(公告)日:1987-05-26

    申请号:CA455081

    申请日:1984-05-24

    Applicant: BASF AG

    Abstract: The invention relates to a process for the separation of a C4-hydrocarbon mixture which essentially contains n-butenes and butanes. This process is characterized in that the mixture is reacted with a carboxylic acid in the presence of an acidic catalyst to form a butyl carboxylate; the reaction mixture obtained from the esterification zone is distilled to give, as the top product, a fraction containing the butanes, and, as the bottom product, a fraction containing the resulting butyl carboxylate; the butyl carboxylate is decomposed at elevated temperatures to give the carboxylic acid and n-butenes; and the mixture of n-butenes and carboxylic acid is then distilled, the n-butenes being obtained as the top product, and the carboxylic acid as the bottom product. This process permits to use apparatus that are less expensive than those required for the conventional extractive distillation method.

    OBTAINING A CONJUGATED DIOLEFIN FROM A MIXTURE OF C.SUB.4 OR C.SUB.5 HYDROCARBONS

    公开(公告)号:CA1182774A

    公开(公告)日:1985-02-19

    申请号:CA402343

    申请日:1982-05-05

    Applicant: BASF AG

    Abstract: A process for obtaining a conjugated diolefin from a mixture of C4 or C5 hydrocarbons which contains this diolefin, by single-stage or multistage extractive distillation using a selective solvent and recycling the latter to the extractive distillation, after it has been obtained from the stripping zone downstream from each extractive distillation, a bleed stream of the recycled selective solvent being regenerated in a solvent purification stage in which the high-boiling or non-volatile impurities present in the solvent are separated off, and the regenerated solvent obtained from the solvent purification stage also being recycled, which process comprises regenerating the solvent in a thin-film evaporation zone.

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