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    PROCESS FOR PREPARING ACRYLIC AND METHACRYLIC ACIDS
    72.
    发明专利
    PROCESS FOR PREPARING ACRYLIC AND METHACRYLIC ACIDS 未知

    公开(公告)号：CZ7399A3

    公开(公告)日：1999-05-12

    申请号：CZ7399

    申请日：1997-07-09

    Applicant: BASF AG

    Inventor： ECK BERND ,  MACHHAMMER OTTO ,  PROLL THEO ,  SCHLIEPHAKE VOLKER

    IPC: C07C57/04 ,  C07C51/21 ,  C07C51/43 ,  C07C57/05 ,  C07C57/07

    Abstract: A process for preparing acrylic acid or methacrylic acid comprises(a) 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, characterized by(b) condensing said product mixture,(c) crystallizing acrylic acid or methacrylic acid from the solution obtained in step (b), and(d) removing the resulting crystals from the mother liquor.

    METHOD FOR PRODUCING ACRYLIC ACID AND METHACRYLIC ACID
    74.
    发明专利
    METHOD FOR PRODUCING ACRYLIC ACID AND METHACRYLIC ACID 未知

    公开(公告)号：CA2303445A1

    公开(公告)日：1999-03-25

    申请号：CA2303445

    申请日：1998-09-09

    Applicant: BASF AG

    Inventor： BROLLOS KLAUS ,  THIEL JOACHIM ,  SCHLIEPHAKE VOLKER ,  MACHHAMMER OTTO ,  PROLL THEO ,  ECK BERND

    IPC: C07C51/43 ,  C07C51/44 ,  C07C57/07

    Abstract: The invention relates to a method for producing acrylic acid and methacrylic acid by producing a gaseous product mixture which essentially has the composition of a reaction mixture of the catalytic gas phase oxidation of C3/C4- alkanes, -alkenes, -alkanols or -alkanals or precursors thereof to form acrylic acid or methacrylic acid. The product is separated from the gaseous product mixture according to a method comprising the following steps: a) condensing the gaseous product mixture; b) crystallising the acrylic acid or methacrylic acid from the solution obtained in (a); c) separating the resulting crystals from the mother liquor and d) returning at least a part of the mother liquor from stage (c) to stage (a).

    PURIFICATION OF ACRYLIC AND METHACRYLIC ACIDS
    78.
    发明专利
    PURIFICATION OF ACRYLIC AND METHACRYLIC ACIDS 未知

    公开(公告)号：CZ43697A3

    公开(公告)日：1997-09-17

    申请号：CZ43697

    申请日：1997-02-12

    Applicant: BASF AG

    Inventor： MACHHAMMER OTTO ,  DAMS ALBRECHT ,  ECK BERND ,  PROLL THEO

    IPC: C07C57/04 ,  C07C51/43 ,  C07C57/05 ,  C07C57/07

    Abstract: A process for purifying (meth)acrylic acid by phase separation techniques comprises the following steps: (a) a mixture containing (meth)acrylic acid is separated into distinct phases in the presence of an organic solvent, with the composition of the (meth)acrylic acid-rich phase remaining essentially unchanged, and this acid-rich phase is separated; (b) the remaining phase from step (a) is separated into indistinct phases; and (c) one of the phases from step (b) is returned to step (a). Also claimed is preparation of (meth)acrylic acid. Preferably in step (c) the acid-rich phase is returned to step (a). 1-100 (100) wt.% of the phase remaining from step (a) is used in step (b). Pure end product is added to steps (a) and (b). Step (a) involves crystallisation, freezing or sublimation, preferably static and/or dynamic crystallisation, and most preferably a combined static and dynamic crystallisation in which the residue from the dynamic crystallisation is added to the static crystallisation step and the crystallised product from the static crystallisation is returned to the dynamic crystallisation.

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