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    Polymerisation inhibitor mixture containing p-phenylene diamine
    22.
    发明专利
    Polymerisation inhibitor mixture containing p-phenylene diamine 未知

    公开(公告)号：DE19735223A1

    公开(公告)日：1999-02-18

    申请号：DE19735223

    申请日：1997-08-15

    Applicant: BASF AG

    Inventor： AICHINGER HEINRICH DR ,  HERBST HOLGER DR ,  NESTLER GERHARD DR

    IPC: C07C67/62 ,  C07C69/54

    Abstract: A process for the stabilisation of esters of (meth)acrylic acid as a pure substance or as a component within a mixture that does not contain a Bronsted acid having a Bronsted acid strength greater than that of acrylic acid is claimed by addition of a p-phenylene diamine containing polymerisation inhibitor as a pure substance or mixture of inhibitors that contains (A) a nitroxyl radical and/or an organic compound containing a nitroso group and (B) a p-phenylene diamine.

    CONTINUOUS PREPARATION OF (METH)ACRYLIC ACID ALKYL ESTERS
    28.
    发明专利
    CONTINUOUS PREPARATION OF (METH)ACRYLIC ACID ALKYL ESTERS 未知

    公开(公告)号：CZ30997A3

    公开(公告)日：1997-10-15

    申请号：CZ30997

    申请日：1997-02-03

    Applicant: BASF AG

    Inventor： SCHMIDT WILLI ,  MATTHIAS GEISENDORFER DR ,  DOCKNER TONI DR ,  HERBST HOLGER DR ,  NESTLER GERHARD DR

    IPC: B01J31/02 ,  C07B61/00 ,  C07C67/08 ,  C07C67/54 ,  C07C69/54

    Abstract: In the continuous production of alkyl (meth)acrylates (AA) by reacting (meth)acrylic acid with 1-8 carbon (C) monohydric alkanols in homogeneous liquid phase, free from solvent, at elevated temperature and in the presence of an acid esterification catalyst; (a) (meth)acrylic acid, alkanol and catalyst are fed to a reaction zone; (b) during a residence time, the water formed is separated in a rectification unit (RU) III above the reaction zone; (c) the aqueous distillate is separated into an organic phase containing the alkanol and an aqueous phase; (d) the organic phase is recycled to RU III; and (e) the reaction mixture is discharged from the reaction zone and passed to another RU, where AA is separated by distillation. The novel features are that: (i) the molar ratio of (meth)acrylic acid and alkanol is 1:(0.75-2); (ii) the aqueous phase from RU III is partly recycled to RU III; (iii) the reaction mixture is passed to RU I, in which it is separated into a product (II) containing the catalyst and a product (I) containing AA, residual alkanol and residual (meth)acrylic acid; and (iv) (I) is passed to RU II, in which AA is separated from residual alkanol and residual (meth)acrylic acid and the alkanol and acid are recycled to the reaction zone. Preferably the alkanol is 2-ethylhexanol. The catalyst is para-toluenesulphonic acid (p-TSA) and/or other organic sulphonic acids, e.g. methane-, benzene- or dodecylbenzene-sulphonic acid, and/or sulphuric acid (H2SO4). The catalyst concentration in the reaction mixture is 0.1-10, especially 0.1-6 wt.% p-TSA in the reaction zone and 2.5-50 wt.% p-TSA in the sump or an equimolar amount of organic sulphonic acid and/or H2SO4. The reaction zone consists of a cascade of NOTLESS 2, especially 2-4 consecutive sections, especially reactors with circulating vapourisers. All rectification units are rectification columns.

    30.
    发明专利
    未知

    公开(公告)号：DE19501325A1

    公开(公告)日：1996-07-25

    申请号：DE19501325

    申请日：1995-01-18

    Applicant: BASF AG

    Inventor： HERBST HOLGER DR ,  NESTLER GERHARD DR ,  HAMMON ULRICH DR

    IPC: C07C57/04 ,  C07C51/44 ,  C07C57/05 ,  C07C57/07

    Abstract: In the sepn. of (meth)acrylic acid (I) from mixts. by rectification, in which (I) is discharged from the column at a point higher than the inlet for the mixt., the refluxing liq. is removed in at least one position of the column, the oligomerised and/or polymerised (I) is sepd. and the liq. is recycled to the column.

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