Technology and Development of Diphenyl Methane-4,4’-Diisocyanate

The research of continuous condensing,purifying MDI and reducing product color value was reviewed in producing MDI by phosenge approach. The research of catalysts that involved in the reaction of synthesizing MPC, catalysts, methylating agent,solvent that involved in the reaction of synthesizing Diphenylmethane Dicarbamic(MDU), catalysts, solvent that involved in the thermolysis reaction of synthesizing MDI were reviewed in producing MDI by non-phosenge approach. There are some disadvantages in phosenge approach. The method producing MDI by carbamate decomposeing is research focus.