Mitsui Toatsu Chemicals, Incorporated

Akinobu Takagi

Ryuichi Yamamoto

Mitsumasa Umemoto

Takeshi Nishida

Yutaka Hirai

Tamotsu Asano

Masafumi Kataita

Kenji Obata

Hironobu Horie

Zyunzi Tashima

Shigeki Mori

Nobuyasu Tamura

Process for preparation of 3-phenoxybenzyl

A two-stage continuous preparation process for organic isocyanates uses a primary amine which is reacted with stoichiometrically excess phosgene at a gauge pressure of 10 Kg/cm.sup.2 or lower and a temperature of 60.degree.-100.degree. C. in an inert organic solvent. Then, the resultant reaction mixture is maintained at a gauge pressure of 10 Kg/cm.sup.2 or lower and a temperature of 120.degree.-160.degree. C. until the reaction is completed.

Continuous preparation of organic isocyanates

Lactam-blocked products of alicyclic isocyanates are obtained by blocking an aromatic isocyanate with lactam and subjecting the resulting blocked product to catalytic hydrogenation with use of a Rh catalyst. The blocked alicyclic isocyanate obtained thus can be used, for example, as a curing agent for synthetic resins such as epoxy resins or as a starting material of urethane coatings. The blocked isocyanate, if desired, may be subject to distillation whereby an alicyclic isocyanate is isolated by thermal dissociation and separation of the blocking agent.

Process for preparing alicyclic isocyanates

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Omuta, Japan

Akinobu Takagi