Oxygenates water tolerance

The oxygenate must tolerate at least 1000 ppm of water and should not separate into two phases. 

The butanols and their methyl and ethyl ethers have several advantages as oxygenates over methanol and ethanol in gasoline blends. Their energy contents are closer to those of gasoline the compatibility and miscibility problems with petroleum fuels are nil excessive vapor pressure and volatility problems do not occur and they are water tolerant and can be transported in gasoline blends by pipeline without danger of phase separation due to moisture absorption. Fermentation processes (Weizmann process) have been developed for simultaneous production of 1-butanol, 2-propanol, acetone, and ethanol from... 

Whereas gasoline and water are almost entirely immiscible, and will readily separate into two phases, a gasoline-oxygenate blend is used to dissolve water without phase separation, hence the use of the term water tolerance. Gasoline-oxygenate blends will dissolve some water but will also separate into two phases when contacted with water that is beyond the threshold concentration. Such a phenomenon is a major issue for alcohol-containing blends. 

ETBE is made from com ethanol, a domestic renewable oxygenate. This could drastically cut down the dependence on oil imports. As an ether, ETBE displays superior water tolerance properties and can be shipped by pipeline. 

Water tolerance. This is the highest temperature that causes phase separation of oxygenated fuels. The limits vary according to location and month. 

The choice between the various oxygenates is being influenced by cost, availability, and their impact on fuel properties. All have high octane, but alcohols (especially methanol) can have an effect on volatility, water tolerance, and elastomer compatibility. 

Acetone is potentially useful in blends with gasoline as it can increase the oxygen content, the octane rating, and the water tolerance of the fuel (Bolt 1980 Noon 1982). Acetone can also be blended with butanol, ethanol, and water to serve as an automobile fuel (see the next section Butanol in this chapter). 

Based on work with aqueous mthenium-based metathesis systems, stable, active, and well-defined ruthenium metathesis catalysts were developed. As will be demonstrated, the early promise of broadly functional group-tolerant and water-tolerant initiators based on mthenium have been realized. The first complex, 10, was not particularly reactive, but would polymerize norbomene and its derivatives. These complexes were much more stable to functional groups, water, and oxygen than prior systems. It was demonstrated that these systems would give a living polymer with norbomene and could be used to form block polymers. ... 

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