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:
Dec. 12, 2017
Filed:
Apr. 11, 2014
Wanhua Chemical Group Co., Ltd., Yantai, CN;
Hongke Zhang, Yantai, CN;
Yu Yao, Yantai, CN;
Dongke Zhao, Yantai, CN;
Weiqi Hua, Yantai, CN;
Bin Chen, Yantai, CN;
Dekai Shi, Yantai, CN;
Qinglong Chen, Yantai, CN;
Dan Xu, Yantai, CN;
Yang Wang, Yantai, CN;
Qile Shi, Yantai, CN;
Abstract
A solvent refining method for isocyanate prepared by the phosgene method and multistage absorbing towers used in same. Solvent to be refined which contains water, iron, and/or phosgene, hydrogen chloride and other materials with color is dealt by the present method and multistage absorbing towers, which can effectively prevent a drying agent from absorbing water and hardening, partial overheating in the tower and generating channeling. Meanwhile, the pressure drop is effectively lowered. In addition, the content of water is ≦50 ppm, the content of iron is ≦5 ppm, the content of phosgene and hydrogen chloride is ≦20 ppm, Pt—Co chroma is ≦20 in the refined solvent. Therefore, the refined solvent can be used as the solvent for preparing isocyanate in the phosgene method and remarkably improve an L color of isocyanate.