Method for reducing chlorine-containing impurities in isocyanate

• Main Authors: ZHANG TONGXI, LI LING, XIANG WEI, YU GUANGXIONG, MAO JIANYONG, DU QIANQIAN, WANG HUI
• Format: Patent
• Language: Chinese; English
• Published: 09.07.2024
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR RELEVANT APPARATUS; TRANSPORTING

The invention relates to a method for reducing chlorine-containing impurities in isocyanate. The method comprises a step of carrying out hydrodechlorination reaction on an isocyanate crude product obtained by a phosgene method and hydrogen in the presence of a catalyst, the isocyanate crude product comprises chlorine-containing impurities, the catalyst is a supported catalyst and comprises a carrier, an active component and an auxiliary agent, the active component is a group VIII metal, and the auxiliary agent is a group VIII metal or a group VIII metal or a group VIII metal or a group VIII metal or a group VIII metal or a group VIII metal or a group VIII metal or a group VIII metal or a group VIII metal. The auxiliary agent is selected from one or a combination of more of Ag, Cu, Sn, Zn, Cd, In, Ba, K and Au. Preferably, the carrier is alkaline anion exchange resin with a quaternary ammonium functional group. According to the method, the content of chlorine-containing impurities in the isocyanate crude produ