US 7,547,801 B2
Process for the continuous preparation of isocyanates
Fritz Pohl, Brunsbuttel (Germany); Ricardo Serra, Krefeld (Germany); Matthias Ehlers, Mame (Germany); Jeffrey S. Bolton, Dusseldorf (Germany); Gary B. Solak, League City, Tex. (US); Kirk J. Bourgeois, Baytown, Tex. (US); Gregory L. McCullough, Highlands, Tex. (US); Amber R. Hicks, Manvel, Tex. (US); Richard G. Hillman, Houston, Tex. (US); James E. Sager, Highlands, Tex. (US); Xiaoyan Wang, League City, Tex. (US); Spotswood Miller, Friendswood, Tex. (US); Ralf Ochel, Seabrook, Tex. (US); and Sara DeLucia, Pittsburgh, Pa. (US)
Assigned to Bayer MaterialScience LLC, Pittsburgh, Pa. (US); and Bayer MaterialScience AG, Leverkusen (Germany)
Filed on Jun. 26, 2006, as Appl. No. 11/474,795.
Prior Publication US 2007/0299279 A1, Dec. 27, 2007
Int. Cl. C07C 249/00 (2006.01)
U.S. Cl. 560—347 10 Claims
 
1. A process for the preparation of isocyanate by the reaction of an organic amine with phosgene in at least three stages comprising:
a) a first stage conducted in a dynamic mixer,
b) a second stage conducted in at least one reactor, and
c) a third stage conducted in at least one material separating apparatus
in which (1) the second stage reactor pressure is greater than the first stage dynamic mixer pressure, and (2) the third stage material separating apparatus pressure is lower than the pressure in the reactor of the second stage.