Method of preparing an isopropanol and diisopropyl ether oxygenate motor

Abstract

Propene is reacted with water in a multi-stage, fluidized bed catalytic reactor to produce an oxygenate motor fuel additive containing a major proportion of isopropanol (IPA), some diisopropyl ether (IPE) and some water. The molar ratio of water to propene introduced into each catalytic stage of the multi-stage reactor is maintained within a range of from about 2:1 to about 6:1. The temperature of the reactants in each of the catalytic stages is maintained within a range of from about 250.degree. F. to about 300.degree. F. and the pressure at a level of from about 1200 psia to about 3000 psia. The temperature in each catalytic stage increases from the initial catalytic stage to the final catalytic stage with the temperature increase being limited to a value within a range of from about 8.degree. F. to about 2.degree. F. The pressure of the final stage of the catalytic section is controlled so that the reaction product containing the organic constituents including oxygenates provides a concentrated, less dense liquid stream which may be easily separated from the aqueous liquid phase in the final stage. The liquid phase is recycled to the catalytic zone while unreacted propene is separated from the oxygenates. Some water is purposefully retained in the oxygenate to take advantage of the solubilization of the IPA component. Seasonal gasoline component specifications may be met by simply controlling the amount of water allowed to remain in the oxygenate product. Relatively small distillation towers are suitable in the present process because of the 92% conversion factor of the propene entering. Thus, only about 1/3rd of the quantity of unconverted hydrocarbons must be separated in the present process as compared with existing commercial methods for the same yield of motor fuel oxygenates.