Claims
- 1. A continuous process for the preparation of isocyanates by reacting appropriate primary amines with phosgene in the presence of an isocyanate as solvent, characterised in that the primary amine optionally dissolved in an inert, organic solvent is reacted with phosgene which is dissolved in the isocyanate in a quantity of 10 to 60 wt. % based on the isocyanate/phosgene solution, at temperatures of 60 to 180.degree. C. and at pressures of 1 to 30 bar (10.sup.5 to 3.10.sup.6 Pa) to obtain the corresponding isocyanate, wherein the molar ratio of phosgene to amine used is 4:1 to 1:1 and the isocyanate used as solvent is solids-free and has a value for hydrolysable chlorine of less than 2%.
- 2. A process according to claim 1, characterised in that the amine used is an amine of the diaminodiphenylmethane series or mixtures thereof, optionally with higher homologues thereof.
- 3. A process according to claim 1, characterised in that the aromatic amine used is toluene diamine and isomer mixtures thereof.
- 4. A process according to claim 1, characterised in that the reaction of the amine with phosgene is carried out in a tubular reactor.
Priority Claims (2)
Number |
Date |
Country |
Kind |
44 40 917 |
Nov 1994 |
DEX |
|
195 21 800 |
Jun 1995 |
DEX |
|
Parent Case Info
This application is a 371 of PCT/EP95/04354 filed Nov. 6, 1995.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/EP95/04354 |
11/6/1995 |
|
|
5/12/1997 |
5/12/1997 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO96/16028 |
5/30/1996 |
|
|
US Referenced Citations (5)
Foreign Referenced Citations (4)
Number |
Date |
Country |
1191641 |
May 1965 |
DEX |
60-10774 |
Jan 1985 |
JPX |
1255638 |
Dec 1971 |
GBX |
1341311 |
Dec 1973 |
GBX |