Chemical conversion involves a number of widely known and extensively employed processes since the nineteenth century. In fact, the chemical process currently in use for the preparation of biodiesel from biomass (transesterification of oils) is the same as has been used for many years. Feedstocks utilised for the preparation of biofuels are also very similar, with peanut, hemp, corn oil and animal tallow been partially replaced by soybean, rapeseed, recycled oil, forest wastes, trees and sugar cane.

First-generation biodiesel is currently the most common example of a biofuel prepared by chemical conversion. It is currently the most widely developed biofuel in Europe. In 2007, 19 biodiesel plants in the new EU member states were starting operations or were under construction/planning. Relatively large plants (with capacities of 100 000 tonnes/year) can be found in Lithuania, Poland and Romania.

The conventional methodology for the production of biodiesel involves the transesterification of triglycerides (TG) from vegetable oils (palm, corn, soybean, rapeseed, sunflower, etc.) with short-chain alcohols, including methanol and ethanol, to yield fatty acid (m)ethyl esters (FAM/EE) and glycerol as by-products (Scheme 1.1).

However, non-edible feedstocks, including Jatropha, Brasicca species and microalgae oil, are becoming increasingly important nowadays for the production of biodiesel and are considered to be an important asset for future biodiesel production. The methods of biodiesel preparation can be classified into three

types: chemical catalytic (base or acid catalysis: homogeneous and/or heterogeneous), biocatalytic (enzyme catalysis: homogeneous and/or heterogeneous) and non­catalytic processes. Several reviews on the preparation of biodiesel from different feedstocks utilising various technologies can be found in the literature.8-12

The production of related biofuels via chemical processes (i. e. (trans)- esterifications) has also been reported. These biofuels have been specifically developed in research institutions, and commercial processes for their implementation as transport fuels are still under development (see Chapter 7 for more details). For more specific details, the readers are referred to Part II of the book (Chapters 5 and 6 as well as some related content in Chapter 22), in which more detailed information about processes, technologies and biofuels produced will be given.