Biodiesel production direct from high acid value oil with a novel magnetic carbonaceous acid

A novel magnetic carbonaceous acid catalyst was synthesized from glucose and iron chloride by a new method of double hydrothermal precipitation and pyrolysis, and subsequent sulfonation. The catalyst presents high active, stable and recoverable in the production of Jatropha biodiesel with high yields for 3 cycles (90.5%, 91.8%, 90.3%), slight reduction in total acid density (2.43 vs. 2.79 mmol/g) and high catalyst recovery rate of 96.3%.150