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 precursor of molecules with surfactants properties. If direct acetalization of HMF with n-octanol is performed in the presence of strong acids (homogeneous and heterogeneous catalysts), an increase in the 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 with 95% yield by transacetalization. It is possible to achieve high yield in a very short reaction time through a two-step one-pot process, which includes the synthesis of 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 selectivity higher than 96%. The optimized catalyst with an adequate Na content (1.5NaBeta) could be recycled without loss of activity or selectivity.