From Biomass to Chemicals: Synthesis of Precursors of Biodegradable Surfactants from 5-Hydroxymethylfurfural

Abstract

The selective acetalization of 5-hydroxymethylfurfural (HMF) with long-chain alkyl alcohols has been performed to obtain precursors of molecules with surfactant properties. If direct acetalization of HMF with n-octanol is performed in the presence of strong acids (homogeneous and heterogeneous catalysts), an increase in etherification versus acetalization occurs. Beta zeolite catalyzes both reactions. However, if the acidity of a zeolite (Beta) was controlled by partial exchange of H⁺ with Na⁺, the dioctyl acetal of HMF can be achieved in 95 % yield by transacetalization. It is possible to achieve a high yield in a very short reaction time through a two-step one-pot process, which includes the synthesis of the dimethyl acetal of HMF followed by transacetalization with n-octanol. The one-pot process could be extended to other alcohols that contain 6–12 carbon atoms to afford 87–98 % yield of the corresponding dialkyl acetal with a selectivity higher than 96 %. The optimized catalyst with an adequate Na content (1.5NaBeta) could be recycled without loss of activity or selectivity.