Chemically catalytic upgrading of fermentation-derived biobutanol to long-chain biofuels

Abstract

The upgrading of acetone-butanol-ethanol (ABE) mixture from biomass to long-chain biofuels has aroused increasing attention since it is beneficial for alleviating energy crises and promoting high-value utilization of biomass. The main key to the ABE conversion is to find catalysts that are widely available and inexpensive. In this study, a simple way to prepare a low-cost highly dispersed Cu/MgO catalyst for ABE alkylation was proposed, resulting in C5–C11 molecules. The effects of experimental parameters such as reduction method, copper loading, reaction time, reaction temperature, and gas atmosphere on the production of long-chain products were also investigated. Compared to using hydrogen gas for reduction, the use of sodium borohydride in methanol results in the highest long-chain product yields. A copper loading of 2.5% or 5% is optimal, while an excessive copper load causes its aggregation. Within 18 h, the longer the reaction time, the higher the total yield and the higher the proportion of long-chain products. When the temperature increases from 250 °C to 300 °C, the total yield increases while the proportion of by-products decreases. The nitrogen atmosphere is conducive to increasing total production as hydrogen can cause the loss of acetone via hydrogenation.