Roseli Ap. Ferrari1, Anna Leticia M. Turtelli Pighinelli2 and Kil Jin Park2

1Food Technology Institute 2Campinas State University Brazil

1. Introduction

Fossil fuels are, nowadays, the most used worldwide but that are some problems involving their utilization. First of all, the price, which is growing often and makes petroleum no longer economically sustainable. Second, during the burning of petrochemical sources there is emission of very dangerous pollutants for human health, like carbon dioxide that is the main reason of the global warming. In addition, fossil fuels are non-renewable resources, so they will last for a limited period of time. For all these reasons, vegetable oils are emerging as a great alternative fuel, because of their renewable nature and environmental benefits (Ferella et al., 2010).

Despite all the advantages, the use of vegetable oils as fuel has some disadvantages. The direct use in internal combustion engines is problematic because vegetables oils have high viscosity than diesel fuel and low volatility, so they do not burn completely and form deposits in the fuel injectors of diesel engine.

According to specialized literature there are five ways to reduce the problems mentioned above: blending of vegetable oil and diesel, thermal cracking (pyrolysis), microemulsions, esterification and transesterification (Ma & Hanna, 1999). Esterification and transesterification reactions are currently the most favored reaction pathways to produce biodiesel (Janaun & Ellis, 2010).

Biodiesel, defined as the simple alkyl monoesters of long chain fatty acids derived from renewable feedstocks, is the most suitable substitute to diesel. For this reason the research on this biofuel are steadily growing all over the planet. In Brazil, the focus of research is the production of biodiesel using ethanol, since this alcohol is produced on a large scale in the country. Ethanolysis produces a biodiesel less damage to the environment than that produced by methyl alcohol, since ethanol is derived from sugar cane or corn. In the rest of the world, the production takes place mostly in the methyl route and with use of heterogeneous catalysts (Pighinelli, 2010).

Biodiesel is highly biodegradable in fresh water as well as in soil and great part of it is mineralized in until 28 days under aerobic or anaerobic conditions (Makareviciene & Janulis, 2003; Pasqualino et al., 2006; Zhang et al., 1998). It is also a carbon-free fuel, as the plants that serve as raw material for its production absorb more carbon than that which is released during the burning of this biofuel (Antolin et al., 2002; Lang et al., 2001; Sharma et al., 2008; Vicente & Martinez, 2004).

Moreover, when biodiesel is burned in diesel engines the emissions of hydrocarbons, carbon monoxide, particulate matter and sulphur dioxide are reduced with the exception of

nitrogen oxides, that emission increases due to the oxygen content of biodiesel (Canakci et al., 2006; Labeckas & Slavinskas, 2006; Turrio-Baldassarry, 2004).

Biodiesel sold today is still considered expensive, since the production costs involved are influenced by the main raw material, which are vegetable or animal fat and oils. It is estimated that approximately 80% of the total cost of biodiesel production is related to the acquisition of triglycerols source (Pighinelli, 2010). Another problem that has been discussed frequently is the competition between "food production" and "energy production". Some researchers argue that there will be food shortages if the available land is used for oilseed cultivation.

In order to reduce the production costs and to make it competitive with petroleum diesel, biodiesel producers should choose a raw material longer available in their territory, as soybean in Brazil, but also, search for alternatives crops, such as non-edible oils, as Crambe Abyssinica, Jatropha Curcas and others, and also waste frying oils (Marchetti et al., 2007).

The production of biodiesel is considered a current topic of great relevance worldwide. Thus, this chapter will be discussed: how biodiesel is produced, which are the main parameters affecting the chemical reactions and the most important issues for assuring biodiesel quality related to its production as well as some post-production parameters.