Chloroindate(III) ionic liquids as catalysts for alkylation of phenols and catechol with alkenes

摘要

Chloroindate(III) ionic liquids are shown to be versatile catalysts for the alkylation of phenols with alkenes, giving high conversions to alkylated phenols with high selectivities. Alkylated phenols and their derivatives are used in the production of resins, durable surface coatings, varnishes, wire enamels, printing inks, surface active agents, antioxidants, flame retardants, UV absorbers, fungicide and insecticide formulations, petroleum additives, non-ionic surfactants and fragrances.For example, the triphosphate derivative of 2,4-di-tert-butylphenol is employed as a stabiliser for poly(vinyl chloride) (PVC), whereas its benzotriazole derivative is used as a UV absorber in polyalkenes. 4-tert-Butylcatechol is utilised as a polymerisation inhibitor for a number of monomers. Thymol (2-isopropyl-3-methylphenol) and other isopropyl phenols have been used in the production of perfumes, and thymol (in particular) is a precursor of (—)-menthol.