Abstract: Disclosed herein is a process for preparing a reaction product containing methylene diphenylamine, comprising reacting aniline and formaldehyde in the presence of an acid catalyst wherein the acid level of the resulting reaction mixture is reduced during digestion of the reaction mixture.

Abstract: Disclosed herein is a process for preparing a reaction product containing methylene diphenylamine, comprising reacting aniline and formaldehyde in the presence of an acid catalyst wherein the acid level of the resulting reaction mixture is reduced during digestion of the reaction mixture.

Abstract: A process is described for the separation and recovery of isocyanate monomers from isocyanate concentrates which leaves a residue which is liquid and burnable. The process for the separation and recovery of isocyanate monomers from isocyanate concentrates formed in the production of isocyanates and comprising a volatile isocyanate monomer and by-products comprises the steps of:(A) preparing a mixture comprising(A-1) the isocyanate concentrate; and(A-2) an oil solution comprising;(A-2-a) a major amount of hydrocarbon oil, and(A-2-b) a minor amount of at least one ashless dispersant; and(B) heating the mixture to an elevated temperature at reduced pressure whereby isocyanate monomer is distilled and recovered leaving a liquid residue.

Abstract: Disclosed herein is a process for recovering toluene diisocyanate (TDI) from a TDI residue solution, comprising mixing the residue solution with a polyisocyanate consisting essentially of methylenediphenyl diisocyanate (MDI) or MDI in combination with its higher ring oligomer, followed by heating the resulting mixture over a temperature range of 130.degree. to 250.degree. C. for a period of time sufficient to remove free TDI and thermally splittable TDI generated from equilibration of the TDI residue with MDI or the MDI oligomer by either a batch or continuous process.