公开(公告)号：CA1225999A

公开(公告)日：1987-08-25

申请号：CA452343

申请日：1984-04-18

Applicant: BASF AG

Inventor： MERGER FRANZ ,  TOWAE FRIEDRICH ,  HELLBACH HANS ,  ISBARN GUNTHER ,  KOEHLER WALDEMAR

IPC: C07C265/14 ,  C07C67/00 ,  C07C69/00 ,  C07C241/00 ,  C07C263/04 ,  C07C263/06 ,  C07C265/04 ,  C07C119/042

Abstract: MULTIPLE-STEP PROCESS FOR THE PREPARATION OF HEXAMETHYLENE DIISOCYANATE-1,6 AND/OR ISOMERIC ALIPHATIC DIISOCYANATES WITH SIX CARBON ATOMS IN THE ALKYLENE RESIDUE Hexamethylene diisocyanate and/or isomeric alkylene diisocyanates having 6 carbon atoms in the alkylene radical, preferably 2-methylpentamethylene 1,5-diiqocyanate and/or 2-ethyltetramethylene 1,4-diisocyanate are prepared without the use of phosgene in a multiple-step process by means of a) reacting hexamethylene 1,6-diamine and/or isomeric alkylene diamines having 6 carbon atoms in the alkylene radical with urea and alcohol in the presence of dialkyl carbonate and/or carbamic acid alkyl ester as well as, in some cases, catalysts to form hexamethylene 1,6-dialkylurethane and/or isomeric alkylene dialkylurethanes having 6 carbon atoms in the alkylene radical, b) separation and return to reaction step (a) of alcohol, dialkyl carbonate, and/or carbamic acid alkyl ester from the reaction mixture c) evaporation of the hexamethylene 1,6-dialkylurethane and/or isomeric alkylene dialkylurethanes having 6 carbon atoms in the alkylene radical, d) cleavage of the vaporized diurethanes into hexa methylene diisocyanate and/or isomeric alkylene diisocyanate having 6 carbon atoms in the alkylene radical and alcohol, and e) fractional condensation of the cleavage products.