56.
    发明专利
    未知

    公开(公告)号:DE19922722A1

    公开(公告)日:2000-11-23

    申请号:DE19922722

    申请日:1999-05-18

    Applicant: BASF AG

    Abstract: The cracking residues of the oxyester-containing sump product which has been obtained after distilling off unreacted materia and the ester in the catalysed esterification of (meth)acrylic acid with an alcohol are combined with the distillation residue a then hydrolysed in the presence of water and acids or bases. Catalysed esterification of (meth)acrylic acid with an alcohol involves distilling off the unreacted materials and the este leave an oxyester-containing sump product which is either: (a) optionally treated with (meth)acrylic acid or oligomeric acid and then cracked using an acid catalyst other than a (meth)acrylic acid or oligomer, with the cracked product removed to leave a cracking residue; or (b) distilled to remove the oxyester and leave a distillation residue, with the oxyester then being optionally treated and cracked as per (a) above. The novel feature is that the cracking residue from (a) or (b) is hydrolysed together with the distillation residue in the presence of water and acids or bases.

    Continuous production of alkyl (meth)acrylate, useful for producing aqueous polymer dispersions, e.g. adhesive, uses 3-stage pre-purification of reaction mixture, with final extraction with water to remove salts

    公开(公告)号:DE19935453A1

    公开(公告)日:2000-10-19

    申请号:DE19935453

    申请日:1999-07-28

    Applicant: BASF AG

    Abstract: Alkyl (meth)acrylates (I) is produced by reacting (meth)acrylic acid, 4-8 carbon alkanol and a strongly acid esterification catalyst (IV) in a solvent-free phase in a rectification unit; and pre-purification of the mixture containing (I) by extracting most of (IV) with water and reactive extraction with aqueous alkali solution and then with water to remove residual salts and aqueous impurities. Continuous production of alkyl (meth)acrylates (I) by elevated temperature reaction in a solvent-free phase involves: (a) feeding (meth)acrylic acid (II), 4-8 carbon (C) alkanol (III) and a strongly acid esterification catalyst (IV) to a reaction zone, (b) separating the water formed during a residence time in a first rectification unit acting as reaction zone; (c) separating the resultant distillate into an organic phase containing (III) and an aqueous phase, (d) recycling the organic phase to the rectification unit, and (e) discharging the reaction mixture containing (I) from the reaction zone and passing it to pre-purification. Pre-purification involves: (i) separating most of (IV) by extraction with water; and (ii) reactive extraction with aqueous alkali solution to neutralize and extract the strongly acid components. The remaining organic reaction mixture is then passed to a separation zone comprising other rectification units, in which (I) is separated. The novelty is that the organic reaction mixture leaving the second pre-purification stage is extracted with water to remove residual salts and aqueous impurity fractions before it is passed to the separation zone. An Independent claim is also included for the equipment used for pre-purification.

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