Di-isopropyl ether (DIPE) is not currently produced at an industrial level, but it represents an important option as an oxygenate due to its antiknocking properties and low volatility, among other features. However, it presents the disadvantage of the auto oxidation with the subsequent production of low solubility and explosive peroxides. To neutralize this effect, the addition of antioxidants in amounts as small as 20 ppm is enough, which does not allow the production of more peroxides than the ones formed during MTBE synthesis (Ancillotti and Fattore, 1998). DIPE is produced by the addition of water to isopropylene for producing isopropylalcohol, which is added to other molecules of isopropylene obtaining DIPE. Hydration reac­tion is carried out with catalysts of the type ZSM-5 or acid polysulfone resins at 700 to 24,000 kPa. The second reaction is accomplished using acid zeolites at 450 to 7,000 kPa (Harandi et al., 1992). In this case, the need for employing alcohols is eliminated because oxygen is supplied by the water. Like the ETBE, the production of DIPE by reactive distillation has been proposed (Cardona et al., 2000, 2002).

Ethers, as gasoline oxygenates, have demonstrated several advantages derived from their oxygen content, antiknocking properties, and compatibility with the gasoline, among other factors. Nevertheless, the concerns arising from the low biodegradability and high mobility of MTBE have imposed serious limitations to the production of this type of oxygenates in some countries, particularly in the United States where even the usage of ETBE and TAME has been restricted in California. A limiting factor is that the toxicological properties and the environ­mental impacts of these ethers are not sufficiently known. It is considered that due to the similarity in the molecular structure of the different ethers, their properties should be analogous to those of MTBE. For this reason, contamination problems in groundwater as a consequence of using oxygenates like ETBE, TAME, TAEE, or DIPE are expected (Graham et al., 2000; Nadim et al., 2001).