tolylene diisocyanate

noun

: any of six isomeric esters CH₃C₆H₃(NCO)₂ of isocyanic acid or a mixture of them

especially : a liquid isomer made by reaction of tolylenediamine (see tolylenediamine sense a) and phosgene and used by itself or in a mixture with another meta isomer in making polyurethanes; 4-methyl-meta-phenylene diisocyanate

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