One-pot synthesis of cyclohexylphenol via isopropyl alcohol-assisted phenol conversion using the tandem system RANEY® Nickel plus hierarchical Beta zeolite. Issue 23 (7th November 2022)

• Record Type: Journal Article
• Authors: García-Minguillán, A. M.; Briones, L.; Alonso-Doncel, M.; Čejka, J.; Serrano, D. P.; Botas, J. A.; Escola, J. M.
• Is Part Of: Green chemistry. Volume 24:Issue 23(2022)
• Page Start: 9168
• Page End: 9179
• Publication Date: 2022-11-07
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/d2gc01353c
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : Cyclohexylphenols are valuable intermediate chemicals applied in the manufacture of dyes, resins, and pharmaceutical drugs. Abstract : Cyclohexylphenols are valuable intermediate chemicals applied in the manufacture of dyes, resins, and pharmaceutical drugs. However, they are synthesized using raw chemicals derived from fossil fuels rather than sustainable sources ( e.g., lignin-derived phenol). In this article, we report a one-pot synthesis of cyclohexylphenols via phenol-assisted conversion with isopropyl alcohol over the tandem catalytic system formed by RANEY® Nickel plus hierarchical Beta zeolite. Over this tandem catalytic system, cyclohexylphenols were synthesized with remarkable selectivity (∼70%) at high conversion rates (64%) after 1 h of reaction at 150° C. In contrast, higher temperatures (175 °C) were required to obtain alkylphenols over the Al-SBA-15 catalyst, which is highly accessible thanks to its uniform mesoporous structure, albeit with weaker Lewis acid sites. Additionally, selectivity to cyclohexylphenols over Al-SBA-15 was far lower (19%) than over hierarchical Beta zeolite, and cresols were instead the most abundant alkylphenol (26%). Therefore, the combination of suitable accessibility and Brønsted acidity of hierarchical Beta with the hydrogenating ability of RANEY® Ni through catalytic hydrogen transfer from isopropyl alcohol drives the selectivity of this tandem system towards the production of cyclohexylphenols.