TOLYL DIISOCYANATE

Otto Bayer produced PUs in the 1940 s by reacting diisocyanates, such as tolyl diisocyanate, with dihydric alcohols, such as ethylene glycol. In another experiment he added a diisocyanate to cure synthetic rubber (SR) containing hydroxyl groups. The rubber was cured (vulcanized), but it stuck to the mold. Variations of products from these two experiments are now used as two-component adhesives for bonding footwear and automotive plastic parts. 

Starch reacts with isocyanates to produce carbamates (urethanes), which are esters of carbamic acid. Several reactions of starch with phenyl-, various aryl-, 1-naphthyl-isocyanates or 1,6-hexamethylene- and 2,4-tolyl-diisocyanates were conducted either in pyridine or morpholine below the boiling point of these solvents.2546-2548 In each case all three hydroxyl groups of the glucose units reacted to give tricarbanilates, provided a sufficient amount of the isocyanate reagent was used. 

Butcher B, O Neil CE, Reed AIA, et al Radioallergosorbent testing with p-tolyl monoisocyanate in toluene diisocyanate workers. Clin Aller 13 31-34, 1983... 

Tolylene Diisocyanate Tolyl Epoxypropyl Ether Tolyl Glycidyl Ether Tosic Acid Toxaphene... 

Ethyl, n-propyl, n-butyl, and phenyl isocyanates also react with wood without the need for a catalyst but p-tolyl isocyanate, 1,6-diisocyanatohexane, and tolylene 2,4-diisocyanate require either DMF or triethylamine as a catalyst (80). High weight gains are observed with these last three isocyanates, but little or no dimensional stability results from the reaction. Therefore, polymerization must be taking place in the void structure. 

Dibutyltin dilaurate (DBTDL) (M T Chem. Co.), 1,4-diaza [2,2,2.]. octane (Air Products), isocyanatoethyl methacrylate (IEM) and carbamoyl chloride of IEM (Dow Chem. Co.) and hexamethylene diisocyanate were used as supplied. Phenyl isocyanate, p-tolyl isocyanate, p-chlorophenyl Isocyanate (all Aldrich Chem. Co.), 2-ethoxyethyl acetate (Eastman Kodak Co.) and n-butanol (Mallinkrodt) were purified by distillation before use. 

Karol, M. H., Ioset, H. H., Alarie, Y. C. Tolyl-specific IgE antibodies in workers with hypersensitivity to toluene diisocyanate. Am Ind Hyg Assoc J 39 454-58, 1978. 

This is not the case with higher molecular weight isocyanates such as ethyl, n-propyl, n-butyl, phenyl and -tolyl isocyanates, 1,6-diisocyanate hexane and tolylene-2,4-diisocyanate. 

At lower weight add-ons for ethyl, jt-propyl and ji-butyl isocyanates the increase in wood volume is approximately equal to the volume of isocyanate added (Table II). At higher weight add-ons for these and for phenyl and p-tolyl isocyanates, 1,6-diisocyanate hexane and tolylene-2,4-diisocyanate, there is far more volume of chemical added to the wood than there is in expansion of wood volume. This means that polymerization of the isocyanate is taking place in the lumen (homopolymer formation) and little of the chemical ends up in the cell wall. 

In those reactions where the isocyanate enters the cell wall and bulking takes place, the ASE values will be high. If, on the other hand, the isocyanate polymerizes in the lumen and no cell wall bulking takes place, there will be little, if any, ASE as a result of the treatment. Table III shows varying degrees of dimensional stability by reacting southern pine with ethyl, ri-propyl and ji-butyl isocyanate. Less dimensional stability is achieved with phenyl and p-tolyl isocyanates, and 1,6-diisocyanate hexane and none with tolylene-2,4-diisocyanate. 

All chemicals used in this study were reagent grade. Butyl isocyanate (BuNCO, 99% from the Upjohn Chemical Co.), hexamethy-lene diisocyanate (HDI, 99% from the Mobay Chemical Co.), phenyl isocyanate (PhNCO, 99%, from the Upjohn Chemical Co.), p-tolyl isocyanate (MePhNCO, 99% from the Aldrich Chmical Co.), p-chloro-phenyl isocyanate (CIPhNCO, 99%, from the Aldrich Chemical Co.) and cyclohexyl isocyanate (CHI, 98%, from the Aldrich Chemical Co.) were purified by vacuum distillation. Methylene diphenyl diisocyanate (MDI, 99%+, from the Mobay Chemical Co.) was used without further purification. N,N-Dimethylformamide (DMF, reagent grade, from the Mallinckrodt) was dried by molecular sieves 4a. The NCO-terminated prepolymers were prepared from poly(oxy-tetramethylenediol) (POTMD, mol. wt. 650, 1000, 2000, Quaker Oats Chem. Co.) and MDI. 

Toluylene-2,4-diisocyanate. See Toluene-2,4-diisocyanate Toluylene-2,6-diisocyanate. See Toluene-2,6-diisocyanate 1-o-Tolylbiguanide. Seeo-Tolyl biguanide... 

This family of foidamers consists of two, three, or five alternating aromatic heterocydes (pyridazine, pyrimidine, or pyrazine) and methyl-substituted aromatic carbocycles (tolyl, o-xylyl, or m-xylyl) cormected via urea groups (8 Figure 9.3) [14]. In a typical synthesis, heterocyclic diamine compounds were treated with aryl diisocyanate compounds to install a urea linkage between aromatic heterocyde and aromatic carbocyde (Umax = 5). 

Triphosgene is used as a carbonylating agent in the synthesis of 2-tolyl isocyanate 262 and in the synthesis of 4,4 -diphenylmethane diisocyanate (MDI) 264 from the corresponding diamine in high yield (92%) [53]. 

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