Li Z, Wang T, Qi X, Yang Q, Gao L, Zhang D, Zhao X, Wang Y. Green synthesis of benzonitrile using ionic liquid with multiple roles as the recycling agent.
RSC Adv 2019;
9:17631-17638. [PMID:
35520601 PMCID:
PMC9064556 DOI:
10.1039/c9ra02296a]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/18/2019] [Indexed: 01/18/2023] Open
Abstract
Preparation of benzonitrile from benzaldehyde and hydroxylamine hydrochloride is one of the most advantageous approaches. Nevertheless, it suffers from various constraints such as longer reaction time, corrosion and recovery of hydrochloric acid, the use of metal salt catalysts and their separation. For these reasons, a novel green benzonitrile synthetic route was proposed with ionic liquid as the recycling agent in this study. The results indicated that hydroxylamine 1-sulfobutyl pyridine hydrosulfate salt ((NH2OH)2·[HSO3-b-Py]·HSO4) was an expert alternative to hydroxylamine hydrochloride. Meanwhile, the ionic liquid [HSO3-b-Py]·HSO4 exhibited the multiple roles of co-solvent, catalysis and phase separation, thus the use of metal salt catalyst was eliminated, and no additional catalyst was needed. Hence, the separation process was greatly simplified. When the molar ratio of benzaldehyde to (NH2OH)2·[HSO3-b-Py]·HSO4 was 1 : 1.5, the volume ratio of paraxylene to [HSO3-b-Py]·HSO4 was 2 : 1, the benzaldehyde conversion and benzonitrile yield were both 100% at 120 °C in 2 h. Even better, the ionic liquid could be recovered easily by phase separation, and recycled directly after reaction. Additionally, this novel route is applicable to the green synthesis of a variety of aromatic, heteroaromatic and aliphatic nitriles with excellent yields.
ILs exhibited good co-solvent, catalytic, phase separation and recycling performance in the green synthesis of benzonitrile from benzaldehyde and (NH2OH)2·ILs.![]()
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