1,1'-BIPHENYL, 4,4'-DIISOCYANATO-3,3'-DIMETHYL- 137534-82-8 3,3'-Bitolylene-4,4'-diisocyanate 3,3'-Dimethyl-4,4'-biphenylene diisocyanate 3,3'-Dimethyl-4,4'-biphenylene isocyanate