Xin Guo , Zhiyuan Wang , Ye Yang , Jiahui Zhang , Yanduo Liu , Zhiyuan Mu , Siqi Jiang , Chunxiao Ren , Dan Lv , Yufeng Hu , Zhichang Liu
{"title":"Highly efficient catalyzed by imidazolium-based dual-sulfonic acid functionalized ionic liquids for liquid phase Beckmann rearrangement: experiments and COSMO-RS calculations","authors":"Xin Guo , Zhiyuan Wang , Ye Yang , Jiahui Zhang , Yanduo Liu , Zhiyuan Mu , Siqi Jiang , Chunxiao Ren , Dan Lv , Yufeng Hu , Zhichang Liu","doi":"10.1016/j.gce.2023.01.002","DOIUrl":null,"url":null,"abstract":"<div><p>A production technique with the high yield and environmentally friendly process need be developed for ε-Caprolactam (CPL) in the chemical industry. This technology is highly desired to design and synthesize high−performance catalysts for liquid phase Beckmann rearrangement of cyclohexanone oxime (CHO) to CPL. In this work, 3-methyl-1-(propyl-4-sulfonyl) imidazolium methanesulfonate ([PHSO<sub>3</sub>MIM][MSA]) with highly efficient and excellent yield is synthesized successfully. When the optimum molar ratio of ZnCl<sub>2</sub> over [PHSO<sub>3</sub>MIM][MSA] was 0.02, it exhibits the high selectivity (94%) of CPL at 90 °C for 1 h. Interestingly, Fourier-transform infrared (FT-IR) investigations show that the functional Brønsted−Lewis acidic types of ionic liquids (ILs) are formed by the uniformly distributed ZnCl<sub>2</sub> and [PHSO<sub>3</sub>MIM][MSA]. In addition, the hydrogen bond (H-bond) is formed between CHO and ILs. After ten reaction cycles, no significant structure changes are observed in the recovered [PHSO<sub>3</sub>MIM][MSA]·ZnCl<sub>2</sub>. The solubilities of ILs are predicted by using COSMO-RS model, the results show that [PHSO<sub>3</sub>MIM][MSA] is a promising candidate for the liquid phase Beckmann rearrangement of CHO into CPL. Finally, a theoretical model of the H-bond interactions between ILs and CHO is further confirmed to support the advance of reaction mechanism. A feasible way is provided for the CPL production technique in the liquid phase Beckmann rearrangement reaction.</p></div>","PeriodicalId":66474,"journal":{"name":"Green Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":9.1000,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S266695282300002X/pdfft?md5=002bb455dd31b2676ca2f2054ad8ab83&pid=1-s2.0-S266695282300002X-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Green Chemical Engineering","FirstCategoryId":"1089","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S266695282300002X","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
A production technique with the high yield and environmentally friendly process need be developed for ε-Caprolactam (CPL) in the chemical industry. This technology is highly desired to design and synthesize high−performance catalysts for liquid phase Beckmann rearrangement of cyclohexanone oxime (CHO) to CPL. In this work, 3-methyl-1-(propyl-4-sulfonyl) imidazolium methanesulfonate ([PHSO3MIM][MSA]) with highly efficient and excellent yield is synthesized successfully. When the optimum molar ratio of ZnCl2 over [PHSO3MIM][MSA] was 0.02, it exhibits the high selectivity (94%) of CPL at 90 °C for 1 h. Interestingly, Fourier-transform infrared (FT-IR) investigations show that the functional Brønsted−Lewis acidic types of ionic liquids (ILs) are formed by the uniformly distributed ZnCl2 and [PHSO3MIM][MSA]. In addition, the hydrogen bond (H-bond) is formed between CHO and ILs. After ten reaction cycles, no significant structure changes are observed in the recovered [PHSO3MIM][MSA]·ZnCl2. The solubilities of ILs are predicted by using COSMO-RS model, the results show that [PHSO3MIM][MSA] is a promising candidate for the liquid phase Beckmann rearrangement of CHO into CPL. Finally, a theoretical model of the H-bond interactions between ILs and CHO is further confirmed to support the advance of reaction mechanism. A feasible way is provided for the CPL production technique in the liquid phase Beckmann rearrangement reaction.