Production of high quality diesel from cellulose and hemicellulose by the Sylvan process: catalysts and process variables

Abstract

The Sylvan (2-methylfuran) diesel process involves the conversion of pentose biopolymers into premium diesel via furfural, by means of hydroxyalkylation/alkylation and hydrodeoxygenation reactions. In the hydroxyalkylation/alkylation step two Sylvan molecules are reacted with an aldehyde or a ketone to yield C₁₂+ oxygenated intermediate molecules. Thus, the manuscript describes first the performance of the hydroxyalkylation/alkylation step with different soluble and solid catalysts, and among solids delaminated zeolites were identified as promising catalysts. The scope of the process has also been studied by reacting Sylvan with different aldehyde and ketone molecules. It has been found that for the one-step trimerization of Sylvan, sulfuric acid appears the most adequate catalyst and can be reused. The final hydrodeoxygenation step is studied in detail starting with C₁₄ intermediates generated from two Sylvan and one butanal molecules as well as with the product generated by direct trimerization of Sylvan to yield the final corresponding mono-branched paraffinic diesel product. The Sylvan diesel process is an environmentally friendly process able to produce a high yield (87%) of a premium diesel with a cetane number of >70 and upper pour point of −75 °C from non-food biomass.