New process for sustainable fuels and chemicals from bio-based alcohols and acetone
Synthesizing complex and large molecules out of small molecules derived by fermentation processes is a key factor for future processes based on renewable resources. Promising steps are the self-condensation of alcohols and the cross-condensation of alcohols with acetone. The presented continuous heterogeneous-catalytic gas-phase process makes it possible to condense small alcohols and ketones to larger hydrocarbon molecules containing only one atom of oxygen per molecule. After an optional oxygen-removing step such as hydrotreatment, fuel-identical hydrocarbons including jet fuel can be obtained. A tailor-made carbon chain distribution and additionally carbon-chain branching can be achieved. The choice of raw materials, the process conditions and the recycling of intermediate products are tuning factors. The crude or partially distilled product can be used neat as drop-in fuel for diesel. The intermediates - longer ketones, primary and secondary alcohols - also serve as value-added raw materials and intermediates for many chemical applications, i.e. plasticizers, surfactants, alkenes, solvents, fatty alcohols, and lubricants. The presented process offers an attractive alternative to other competing processes producing long-chain hydrocarbons, like Fischer-Tropsch or hydrotreatment of fats and oils. Being based on inexpensive, long-term stable and commercially available catalysts and designed for a wide range of possible raw materials optionally stemming from residues, the suggested route is ready for scale-up. Future process development can be performed on data already gathered on a bench-scale process allowing the production of 10 liters of purified product per week.