Process for the preparation of toluylene diisocyanate, specific mixtures of toluylene diamine and water, and the use of toluylene diamine and water mixtures to prepare toluylene diisocyanate

摘要

Toluylene diisocyanate is produced by nitration of toluene toy yield dinitrotoluene, hydrogenation of the dinitrotoluene, optionally in the presence of a solvent or diluent, to yield a crude solution of toluylene diamine and reaction water, processing the crude solution of toluylene diamine and water to yield an intermediate mixture of toluylene diamine and water wherein the processing is interrupted to result in a water content of about 1-40% by weight, preferably about 2-10% by weight of the intermediate mixture, transporting this intermediate mixture from a first production facility to a second production facility, whereat the intermediate mixture of TDA and water is completed to yield dry toluylene diamine of commercial quality, and followed by phosgenation of the toluylene diamine to give toluylene diisocyanate. It is optional to additionally process the dry toluylene diamine prior to phosgenation.;The invention also relates to intermediate mixtures of toluylene diamine and water which have a solidification point of at most 95° C., and the use of these intermediate mixtures for producing toluylene diisocyanate. It is preferable that the use of these intermediate mixtures to produce toluylene diisocyanate is performed at a site (or location) which is different from the site of production of the intermediate mixtures of toluylene diamine and water.