公开(公告)号：ES2178313T3

公开(公告)日：2002-12-16

申请号：ES99104411

申请日：1999-03-05

Applicant: BASF AG

Inventor： KIEFER MATTHIAS DR ,  SIEGEL WOLFGANG DR ,  THERRE JORG DR ,  PAHL MELANIE ,  AQUILA WERNER DR ,  SCHAFER-LUDERSSEN ULRICH DR

IPC: C07C29/56 ,  C07C29/80 ,  C07C33/02 ,  C07C33/03

Abstract: Continuous production of dimethyl vinyl carbinol (DMVC) comprises reaction of prenol with an aqueous solution of a protonic acid in the bottom or upper part of a rectification column while distilling off the DMVC as an azeotropic mixture with water under specified conditions. Continuous production of dimethyl vinyl carbinol (DMVC) by reaction of prenol with an aqueous solution of a protonic acid in the bottom or upper part of a rectification column while distilling off the DMVC as an azeotropic mixture with water is performed in such a way that (a) the amount of liquid two-phase mixture formed during the reaction is minimized, (b) the DMVC is distilled off with a reflux ratio of at least 2, and (c) the reaction volume (V in ml) and/or the amount of prenol added per hour (P in ml/hour) and/or the proton concentration in the reaction mixture (C in moles/liter) is such that VC/P = 0.001-1 h.mol/l.

公开(公告)号：ES2192006T3

公开(公告)日：2003-09-16

申请号：ES99118458

申请日：1999-09-17

Applicant: BASF AG

Inventor： THERRE JORG DR ,  KAIBEL GERD DR ,  AQUILA WERNER DR ,  WEGNER GUNTER DR ,  FUCHS HARTWIG

IPC: C07B61/00 ,  C07C41/28 ,  B01J27/16 ,  C07C43/15 ,  C07C45/37 ,  C07C45/51 ,  C07C45/54 ,  C07C45/67 ,  C07C47/21 ,  C07C49/203

Abstract: Preparation of citral (I) comprises thermal decomposition of 3-methyl-2-buten-1-al-diprenylacetal and rearrangement of obtained intermediates cis/trans-prenyl-(methyl-butadienyl)-ether (IV) and 2,4,4-trimethyl-3-formyl-1,5-hexadiene (V). (IV) and (V) are continuously distilled off and converted into (I) before or after removal of by-product prenol. Preparation of 3,7-dimethyl-2,6-octadien-1-al (citral) of formula (I) comprises: (1) thermal decomposition of 3-methyl-2-buten-1-al-diprenylacetal of formula (II) optionally in the presence of an acid catalyst to split off 3-methyl-buten-1-ol (prenol) of formula (III) and form cis/trans-prenyl-(methyl-butadienyl)-ether of formula (IV); (2) Claisen rearrangement of (IV) to give 2,4,4-trimethyl-3-formyl-1,5-hexadiene of formula (V); and (3) Cope rearrangement of (V) to form (I). The transitionally formed (IV) and (V) and the desired citral as well as the prenol (III) are continuously distilled out of the reaction mixture and (IV) and (V), before or after distillative separation of (III) and optional by-products, are subjected to rearrangement to form (I) at 100-200 degrees C.