公开(公告)号：DE59707380D1

公开(公告)日：2002-07-11

申请号：DE59707380

申请日：1997-02-20

Applicant: BASF AG

Inventor： MACHHAMMER DR ,  DAMS DR ,  ECK BERND ,  PROLL DR

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.

公开(公告)号：DE50001029D1

公开(公告)日：2003-02-13

申请号：DE50001029

申请日：2000-05-18

Applicant: BASF AG

Inventor： DAMS DR ,  AICHINGER DR ,  HERBST DR ,  NESTLER DR ,  SCHROEDER DR

IPC: C07C67/08 ,  C07C67/327 ,  C07C69/54

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.

公开(公告)号：DE59606209D1

公开(公告)日：2001-01-18

申请号：DE59606209

申请日：1996-09-26

Applicant: BASF AG

Inventor： EXNER DR ,  BAUR DR ,  DOCKNER DR ,  POTTHOFF CHRISTIANE ,  DAMS DR

IPC: C07C67/08 ,  C07C67/54 ,  C07C69/54

Abstract: The continuous prodn. of alkyl(meth)acrylates (I) by the reaction of (meth)acrylic acid (II) and 1-8C monohydric alcohols (III) in homogeneous liq. phase at elevated temp. in the absence of solvent and in presence of an acid esterification catalyst (IV). The process comprises (a) feeding (II), (III) and (IV) continuously into a reaction zone (RZ), (b) removing (I) after a residence time in the form of an azeotrope contg. water or water and (III) in addn. to (I) at the top of a rectifier column (RC) mounted over the RZ, (c) separating the distillate into an organic phase contg. (I) and aq. phase(s) contg. water, (d) recycling part of the organic phase via the top of the column and opt. returning water to the RZ, (e) separating (I) from the rest of the organic phase and removing part of the reaction mixt. continuously from the RZ. The RZ consists of a cascade of at least two reactors in series, and the outflow from one reactor provides the input flow for the next reactor. Also claimed is an appts. for this process.