公开(公告)号：DE59704095D1

公开(公告)日：2001-08-30

申请号：DE59704095

申请日：1997-02-04

Applicant: BASF AG

Inventor： SCHMIDT WILLI ,  GEISENDOERFER DR ,  DOCKNER DR ,  HERBST DR ,  NESTLER DR ,  WECK ALEXANDER

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

公开(公告)号：DE59606299D1

公开(公告)日：2001-02-15

申请号：DE59606299

申请日：1996-09-26

Applicant: BASF AG

Inventor： AICHINGER HEINRICH DR ,  GEISENDOERFER DR ,  HERBST DR ,  NESTLER DR

IPC: C07C27/02 ,  C07C67/08 ,  C07C67/327 ,  C07C67/60 ,  C07C69/54

Abstract: In the esterification of (meth)acrylic acid with an alkanol in the presence of an acid esterification catalyst, in which unreacted starting materials and the (meth)acrylic ester are sepd. by distn., a sump prod. (I) contg. oxy esters (II) is formed. The novelty is that (I) is sepd. and heated at 150-250 degrees C in the presence of acid and at a pressure at which prods. formed by cracking (II) vaporise directly.