34.
    发明专利
    未知

    公开(公告)号:BR9710251A

    公开(公告)日:1999-08-10

    申请号:BR9710251

    申请日:1997-07-09

    Applicant: BASF AG

    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.

    36.
    发明专利
    未知

    公开(公告)号:MX9809574A

    公开(公告)日:1999-03-31

    申请号:MX9809574

    申请日:1997-06-24

    Applicant: BASF AG

    Abstract: PCT No. PCT/EP97/03304 Sec. 371 Date Dec. 30, 1998 Sec. 102(e) Date Dec. 30, 1998 PCT Filed Jun. 24, 1997 PCT Pub. No. WO98/01414 PCT Pub. Date Jan. 15, 19981,4-Dibenzothiazine-comprising crude acrylic acid is purified by crystallization by raising its diacrylic acid content to at least 1% by weight prior to the crystallization step.

    37.
    发明专利
    未知

    公开(公告)号:DE19718088A1

    公开(公告)日:1998-11-05

    申请号:DE19718088

    申请日:1997-04-29

    Applicant: BASF AG

    Abstract: - Crystallisation of a material (I) to be recovered involves (i) evaporation of a fluid (II) from a melt or solution containing (I), (II) and optionally other components; and (ii) condensation or absorption of (II) vapour in a liquid material to form a liquid mixture, in which (I) and (II) are selected from (a) inorganic salts and salts of organic compounds and their solvates, preferably hydrates, in water and/or organic solvents; (b) organic components in a mixture of organic compounds and/or water with close boiling points, where the difference in concentrations of the gas and liquid phases in equilibrium at the crystallisation pressure and temperature is

    39.
    发明专利
    未知

    公开(公告)号:DE19637380C1

    公开(公告)日:1998-04-09

    申请号:DE19637380

    申请日:1996-09-13

    Applicant: BASF AG

    Abstract: The production of neopentyl glycolhydroxypivalate (NPG-HP) granules (I) comprises pouring molten NPG-HP onto a cooling surface so that the melt solidifies, using a melt containing 3 wt.% NPG-HP crystals. Also claimed are: (i) NPG-HP granules (I) obtained by the above process, especially: (a) spherical granules with an average diameter of 3-16 mm; or (b) granules with an average diameter of 20-100 mm and at least two parallel faces 15-30 mm apart; and (ii) the use of a granulating system for the above process, with a precooler (2) for the NPG-HP melt, a precrystalliser (3), and a drop-forming system (4) or a flat spreader to bring the melt onto a cooling belt (6), with a crusher if a flat spreader is used.

    40.
    发明专利
    未知

    公开(公告)号:ID17665A

    公开(公告)日:1998-01-15

    申请号:ID972392

    申请日:1997-07-10

    Applicant: BASF AG

    Abstract: PCT No. PCT/EP97/03304 Sec. 371 Date Dec. 30, 1998 Sec. 102(e) Date Dec. 30, 1998 PCT Filed Jun. 24, 1997 PCT Pub. No. WO98/01414 PCT Pub. Date Jan. 15, 19981,4-Dibenzothiazine-comprising crude acrylic acid is purified by crystallization by raising its diacrylic acid content to at least 1% by weight prior to the crystallization step.

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