Method for separation of close-boiling mixture of polyols

US9926251B2 · kind B2 · utility

Assignee

• DALIAN INSTITUTE OF CHEMICAL PHYSICS, CHINESE ACADEMY OF SCIENCES · CN

Inventors

• Tao Zhang · Beijing, CN
• Shuo Al · 东风镇, CN
• Mingyuan Zheng · Dalian, CN
• Aiqin Wang · Dalian, CN
• Weizhen Li · Beijing, CN
• Xiaodong Wang · Zhejiang, CN

Key dates

• Filing date: Nov 26, 2015
• Grant date: Mar 27, 2018
• Expiry date: Nov 26, 2035

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/584
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

This invention discloses an approach for the separation of the close-boiling mixture of polyols. The raw material is ethylene glycol containing miscellaneous polyols (such as 1,2-propylene glycol and 1,2-butanediol). Over an acid catalyst, these miscellaneous polyols, through (1) a dehydration reaction, (2) pinacol rearrangement, and (3) acetalization or ketalization reaction, are converted into aldehydes (small amounts), acetals, and ketals (trace amount), which are simultaneously and readily separated via distillation. Meanwhile, after the reaction, the mixture is further separated to obtain an ethylene glycol product at a high purity. The invention provides a technique to remove the miscellaneous polyols from ethylene glycol via liquid-phase dehydration reactions under mild conditions, with low energy consumption. In particular, this approach is markedly effective for the removal of 1,2-butanediol that is difficult to be removed via conventional techniques. The purity of the resulting ethylene glycol product is high, and value-added acetals or ketals are co-produced.