Optimal catalysts and process variables for the Sylvan process for renewable diesel from biomass

11 February 2012

Dr. Avelino Corma and colleagues at Universitat Politècnica de València (Spain) report in a new paper in the RSC journal Energy & Environmental Science on optimal catalyst and process variables for their Sylvan process to produce high-quality diesel from cellulose and hemicellulose. (Earlier post.)

The process uses platform molecules derived from hexoses (5-methylfurfural) and from pentoses (2-methylfuran, or Sylvan) from lignocellulosic biomass through two consecutive catalytic steps that involve hydroxyalkylation/alkylation and hydrodeoxygenation, with an overall yield of 87%. 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.

—Corma et al.

Resources

• Avelino Corma, Olalla de la Torre and Michael Renz (2012) Production of high quality diesel from cellulose and hemicellulose by the Sylvan process: catalysts and process variables. Energy Environ. Sci. doi: 10.1039/C2EE02778J