10-03-2016 дата публикации
Номер: US20160068472A1
Автор:
Chen Hao,
Ding Hao,
Gao Shan,
Hua Weiqi,
Jiang Qingmei,
Li Xin,
Li Yuan,
Liu Zhenguo,
Liu Zhipeng,
Song Jinhong,
Tang Lei,
WANG Weijia,
Zhang Congying
Принадлежит:
Disclosed is a method for preparing diamino-dicyclohexyl methane (HMDA) by hydrogenation of diamino-diphenyl methane (MDA). In the process, 4,4′-MDA used as the starting material is firstly hydrogenated to prepare 4,4′-HMDA. When the activity of the catalyst is reduced, the feed is switched from 4,4′-MDA to the mixture of 2,4′-MDA and 4,4′-MDA, and then when the conversion is stabilized, the feed is switched to 4,4′-MDA again. The deactivated catalyst is activated on line by switching the feed to the mixture of 2,4′-MDA and 4,4′-MDA. 4,4′-HMDA having the trans-trans isomer content of 16˜24 wt % is produced, and the mixture of 2,4′-HMDA and 4,4′-HMDA is also produced, wherein the content of 2,4′-HMDA in the mixture is 4˜15 wt %. 1. A method for preparing diamino-dicyclohexyl methane , wherein said method comprising the following steps:1) 4,4′-diamino-diphenyl methane feed is hydrogenated in a reactor packed with catalyst to prepare 4,4′-diamino-dicyclohexyl methane at the conversion of 98-99.99%;2) When the conversion in step 1) is 90-98%, the feed is switched from 4,4′-diamino-diphenyl methane to a mixture of 2,4′-diamino-diphenyl methane and 4,4′-diamino-diphenyl methane, and the hydrogenation reaction is continued to prepare 2,4′-diamino-dicyclohexyl methane and 4,4′-diamino-dicyclohexyl methane;3) After the conversion of the mixture of 2,4′-diamino-diphenyl methane and 4,4′-diamino-diphenyl methane in step 2) is ≧90% and the reaction is lasted at said conversion for 20-40 h, the feed is switched from the mixture of 2,4′-diamino-diphenyl methane and 4,4′-diamino-diphenyl methane to 4,4′-diamino-diphenyl methane, and the hydrogenation reaction is continued to prepare 4,4′-diamino-dicyclohexyl methane.2. The method as claimed in claim 1 , wherein the 4 claim 1 ,4′-diamino-diphenyl methane feed is composed of 98-100 wt % 4 claim 1 ,4′-diamino-diphenyl methane claim 1 , 0-2 wt % 2 claim 1 ,4′-diamino-diphenyl methane claim 1 , 0-1 wt % N-methyl-4 claim 1 ,4′-diamino ...
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