Catalytic production of biodiesel and diesel-like hydrocarbons from triglycerides

Abstract

Because of their high viscosity and density, crude fats and oils extracted from animal or vegetable sources (containing mainly triglycerides) cannot be directly combusted in modern diesel engines; therefore, they must be converted into biofuels. This important transformation is currently a technological bottleneck for the generation of biofuels either by thermocatalytic cracking to produce diesel-like hydrocarbons or by alcoholysis to yield mono-alcohol fatty acid esters (biodiesel). Although both transformations are relatively simple chemical reactions (thermolysis ((hydro)cracking) and (trans)esterification of triglycerides), they have several drawbacks, mainly related to catalyst efficiency and water and energy consumption. The most recent catalytic approaches and achievements, such as alcoholysis of triglycerides under multiphase conditions using classical acid or base catalysts as well as biocatalysts, are highlighted and discussed.