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AssigneeMitsubishi Gas Chemical Company, Inc.
InventorsTakashi Okawa, Tomoo Tsujimoto, Hideo Ikarashi, Masaharu Doya, Yutaka Kanbara
Estimating the term…
Provided a process for producing higher content of trans 1,4-bis(aminomethyl)cyclohexane which is used as the raw material for producing polyamides or polyurethanes having physically and chemically excellent properties from 1,4-bis(aminomethyl)cyclohexane which is generally produced by hydrogenation of p-xylylenediamine. That is, a mixture of cis and trans 1,4-bis(aminomethyl)cyclohexane is isomerized by heating at 120 to 250.degree. C. in the presence of a platinum group catalyst to change to trans isomer. 1,4-bis(aminomethyl)cyclohexane containing more than 80% trans isomer is produced by combining this isomerization technique and crystallization technique.
A method for isomerization of 1,4-bis(aminomethyl)cyclohexane which consists essentially of heating cis 1,4-bis(aminomethyl)cyclohexane at 120 to 250.degree. C. in the presence of a platinum group catalyst to isomerize it in the absence of hydrogen and optionally in the presence of ammonia to trans isomer.
A process for producing trans 1,4-bis(aminomethyl)cyclohexane, which comprises isomerizing cis 1,4-bis(aminomethyl)cyclohexane at 120 to 250.degree. C. in the presence of a platinum group catalyst to form an isomerized liquor containing trans isomer in a first step, separating crystals of the trans isomer from the isomerized liquor by crystallization in a second step, and recycling the mother liquor separated by crystallization to the first step to isomerize it.
Dependencies are inferred from the claim text.