Paraphenylene diisocyanate

PPDI PPG Prepolymer Processability initiating agent. An abbreviation for paraphenylene diisocyanate. Polypropylene glycol. The product from reacting a polyol with an isocyanate. The relative ease with which a raw or compounded polymer can be handled. 

Paraphenylene Diisocyanate (PPDI) and Cyclohexyl Diisocyanate (CHDI) US Government Federal Hazardous Substances Act and EEC regulations... 

Paraphenylene diisocyanate is another important isocyanate. It produces excellent elastomers but its use is limited due to a very high price. 

Paraphenylene diisocyanate (PPDI) (Parathion) see Ethyl parathion (PCB) see Polychlorinated biphenyls 104-49-4 CX... 

Methylene bisphenyl-4,4 -diisocyanate Paraphenylene diisocyanate crude Polymethylene polyphenyl isocyanate Toluene-1,3-diisocyanate Toluene-2,4-diisocyanate Toluene-2,4-diisocyanate >70% Toluene-2,6-diisocyanate... 

Isoouanates. Various isocyanates are employed in the polymer industry. These compounds are powerful irritants and they are highly toxic. Of particular interest are methylene-di-paraphenylene isocyanate (MDI) and toluene-2,4-diisocyanate (TDI). Various alkyl isocyanates (e.g., methyl, ethyl, propyl, butyl, and cyclohexyl) derivatives may also be of current interest with respect to potential occupational health hazards. Simultaneous analysis of MDI and TDI by HPLC has been accomplished by a modification of the method of Dunlap et al. (28). Air samples are collected in impingers containing p-nitrobenzyl-n-... 

The production of aniline is a major international business, carried on in the US, Europe and Asia, mainly for the conversion, by reaction with formaldehyde under acid-catalyzed conditions, into diaminodiphenylmethanes 9a, 9b and 9c, and then into isocyanates, mainly 4,4/-methylenebis(phenylisocyanate) (MDI, also known as 4,4 -methylene-di-paraphenylene isocyanate, 4,4 -diphenylmethane diisocyanate, methylene diphenylene diisocyanate and diisocyanato diphenyl methane) (9d), from which polyurethanes are produced. This accounts for well over 60% of total demand (Figure 1). Aniline is also used in bulk for the production of antioxidants and vulcanization accelerators for rubber. Some 15.5 million lbs. of cyclohexylamine are made each year mainly by catalytic hydrogenation of aniline. Half the demand is for use as a boiler water additive. Other major uses include in the manufacture of herbicides, plasticizers, emulsifying agents, dyes, dry-cleaning soaps, acid gas absorbents and, in Asia, cyclamate sweeteners. Apart from India, the use of aniline for dyestuff manufacture represents about 10% of demand. 

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