The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 28, 2017
Filed:
Nov. 22, 2013
Wanhua Chemical Group Co., Ltd., Yantai, Shandong, CN;
Wanhua Chemical (Ningbo) Co., Ltd., Ningo, Zhejiang, CN;
Xin Li, Shandong, CN;
Hao Chen, Shandong, CN;
Congying Zhang, Shandong, CN;
Shan Gao, Shandong, CN;
Zhenguo Liu, Shandong, CN;
Weijia Wang, Shandong, CN;
Lei Tang, Shandong, CN;
Zhipeng Liu, Shandong, CN;
Yuan Li, Shandong, CN;
Qingmei Jiang, Shandong, CN;
Jinhong Song, Shandong, CN;
Weiqi Hua, Shandong, CN;
Hao Ding, Shandong, CN;
Wanhua Chemical Group Co., Ltd., Ningbo, Zhejiang, CN;
Abstract
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 %.