Conditions of phase stability in a gasoline-methanol-cyclohexanol-water system

The problem of using methanol as a component of automotive gasoline has arisen recently in connection with the search for sources of nonpetroleum raw materials for production of motor fuel. The use of methanol as an additive to gasoline may be promising if the problem of stabilizing gasoline-methanol mixtures is solved (these mixtures separate under certain conditions unless stabilizers are added). We are testing as motor fuel a isobutanol-stabilized gasoline-methanol mixture. If gasoline-methanol mixtures are put into extensive use, the existing isobutanol plants cannot meet the need for the stabilizers. The search for more economical and efficient stabilizers may include cyclohexanol, which is produced on an industrial scale. We have tested the effect of added cyclohexanol and water on the separation point of gasoline-methanol mixtures in a wide range of CH/sub 3/OH concentrations. The data offer an answer to the question of what the separation temperature of gasoline-methanol mixtures will be in a wide range of methanol concentrations in dependence on the concentration of cyclohexanol and water in them. From these data we constructed the dependence of the separation temperature of gasoline-methanol mixtures containing 15% methanol on the amount of cyclohexanol and water in them. The increase of the separationmore » temperature of the gasoline-methanol mixtures with an increase of the amount of water in them is lower, the higher the concentration of cyclohexanol, i.e. a decrease of the methanol:cyclohexanol ratio permits the amount of water in these mixtures to be increased. Thus, the addition of cyclohexanol to a gasoline-methanol system contributes to a decrease of the separation temperature of gasoline-methanol mixtures.« less