ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Preparation of Lewis acid ionic liquids for one-pot synthesis of benzofuranol from pyrocatechol and 3-chloro-2-methylpropene
Han-Cheng Zhou, Xiu-Lei Li, Juan-Li Liu, Cheng Peng, Bin Zhang, Jin Chen, Qiong Su, Lan Wu, and You-Zhu Yuan
Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest University for Nationalities, Lanzhou 730030, China
Abstract: Several Lewis acid ionic liquids (LAILs) with different acidic scales were synthesised and used as catalysts for the synthesis of benzofuranol by condensation of pyrocatechol and 3-chloro-2- methylpropene in one pot. The catalytic activity of these ionic liquids was correlated with their Lewis acidity. Low to moderate conversion with excellent selectivity to benzofuranol was obtained in the presence of the appropriate LAILs. Compared to the two-step synthetic method currently used in industry, a higher yield plateau (81.1 %) of benzofuranol was achieved in the presence of [BMIm][AlCl4] IL as catalyst at 418 K after 4 h. Furthermore, the catalyst is readily separated from the resultant products via decantation and could be reused after treatment in vacuum.
Keywords: benzofuranol – condensation – Lewis acid ionic liquid – acidity
Full paper is available at www.springerlink.com.
Chemical Papers 69 (10) 1361–1366 (2015)