Alcohols are an oxygenation alternative for gasoline considering the environmental disadvantages of the ethers mentioned above. The blends of alcohols and gasoline have comparable properties related to the traditional fuels based on oil. Despite their lower combustion heat compared to gasoline, the increase in fuel consumption when alcohols are used as oxygenates is not significant in principle. Moreover, the possi­bility of increasing the conversion of the blend and, therefore, the engine efficiency, represents a great advantage for alcohol-containing gasoline. Furthermore, the emis­sions of hydrocarbons and carbon monoxide are reduced, although a considerable increase in the emission of aldehydes is presented (Rasskazchikova et al., 2004).

In the 1970s, several researches were carried out in countries like Japan, the United States, and Germany aimed at the utilization of methanol (CH3OH) as an additive for enhancing the octane number of gasoline (see Table 1.1). Ethanol was pushed into the background due to its high comparative costs. However, despite its high octane number, methanol usage was limited and even banned in many countries due to its high toxicity, volatility (the highest RVP values of the ana­lyzed oxygenates), and hygroscopicity, which generates a series of technical dif­ficulties for the use of methanol-gasoline blends. Furthermore, the formaldehyde formed during methanol oxidation results in the formation of a substance consid­ered dangerous (Rasskazchikova et al., 2004).

At the beginning of the 1980s, the mixture of methanol and tert-butyl alcohol was commercialized under the trademark Oxynol™. Nevertheless, the high vola­tility of the blends containing methanol, due to the formation of one azeotrope with the gasoline hydrocarbons, caused the market to refuse it (Ancillotti and Fattore, 1998). Currently, methanol is employed as feedstock for the production of MTBE and TAME.