公开(公告)号：US3073754A

公开(公告)日：1963-01-15

申请号：US383360

申请日：1960-01-21

Applicant: BASF AG

Inventor： AROYAN HARRY JAMES ,  SINN RICHARD ,  SCHERF KARL ,  VOGEL LUDWIG

IPC: B01D9/00 ,  C07C69/82

CPC classification number: B01D9/0013 ,  B01D9/0059 ,  C07C67/54 ,  C07C69/82

Abstract: Pure dimethyl terephthalate is recovered from mixtures of the ester with methanol, water and other impurities by a process in which a distillation column 1 is maintained at a pressure at which the condensation temperature of the vaporized methanol-water mixture is above the solidification temperature of the ester, i.e. at least 8 atmospheres, an overhead fraction of methanol, water and low-boiling impurities is led off by line 5 to a second, dehydrating, distillation column 10 from which pure methanol is obtained overhead by line 11 and water and impurities are drained off by line 35, the ester mixed with high-boiling impurities is led by line 9 into a third distillation column 14 maintained at atmospheric or slightly elevated pressure up to 1 atmosphere gauge, to which column methanol vapour is also fed by line 13, and the pure ester is separated from methanol after the fraction consisting of ester and methanol distilled off by line 18 is condensed. High-boiling impurities are discharged by line 16. Crude mixtures preferably contain 1.5 to 8 parts of methanol per part of ester and the water content is between 1 and 30% of the methanol content. Two columns instead of column 1 may be used. The vapours in line 18 are condensed at atmospheric or reduced pressure in a vessel 20 and the condensate is cooled further, e.g. to between 40 DEG C. and -10 DEG C., in a container 21 to crystallize the ester, which is then separated from methanol in a centrifuge 24. The ester, after washing, if desired, with methanol from line 26, is passed to a drier 28 while excess methanol is passed to a reservoir 25 for use in the esterification of terephthalic acid or for circulation to the second column 10 by line 33.

公开(公告)号：US3449238A

公开(公告)日：1969-06-10

申请号：US3449238D

申请日：1966-08-26

Applicant: BASF AG

Inventor： STOCKBURGER DIETER ,  SINN RICHARD ,  RAICHLE LUDWIG ,  BUSCHMANN KARL ,  STEGE WOLF-DIETER

IPC: C09C1/56 ,  C10G17/04 ,  B01D1/16

CPC classification number: C09C1/56 ,  C01P2004/51 ,  C01P2004/61

公开(公告)号：US2828330A

公开(公告)日：1958-03-25

申请号：US49230355

申请日：1955-03-04

Applicant: BASF AG

Inventor： SINN RICHARD

IPC: C07C69/82

CPC classification number: C07C67/52 ,  C07C69/82