GB651275A - A process of producing ethyl alcohol - Google Patents

Abstract

<PICT:0651275/IV (b)/1> Ethyl alcohol is continuously prepared by the hydration of ethylene by passing a mixture of ethylene and water vapour at elevated temperature and pressure into intimate contact with a catalyst bed made up of a solid porous support containing absorbed phosphoric acid, of a concentration of at least 70 per cent, the acid having been supplied to the support in a more dilute form and been concentrated in situ on the support. The solid support for the phosphoric acid may be any strong, porous material having good absorptivity for aqueous phosphoric acid. The preferred material is a calcined diatomaceous earth, preferably the product sold under the trade name "Celite". The solid supporting material is impregnated with an aqueous solution of phosphoric acid, preferably of concentration between 55 and 65 per cent to form the catalyst bed which is then heated, preferably by recycling heated ethylene gas through the system under pressure until its temperature reaches 175-200 DEG C. Steam is then gradually mixed with the ethylene and the temperature is raised until when the desired operating ratio of steam to ethylene is established a temperature of 270-280 DEG C. is reached. The average temperature of the bed is controlled between 270 DEG and 310 DEG C., preferably between 290 DEG and 300 DEG C. In the Figure, various curves show how a given concentration of phosphoric acid may be attained at any given temperature by using one of the many combinations of pressure and water vapour-ethylene molecular ratio. As the reaction progresses some phosphoric acid is lost from the bed and to maintain the efficiency of the catalyst it is desirable to add further amounts of phosphoric acid to the bed, the quantity added depending on the amount of ethyl alcohol formed. The ethylene used in the process may be obtained from the catalytic or thermal cracking of petroleum hydrocarbons. If the ethylene is contaminated with acetylene the reactants should be copper-free and should be conducted to the catalyst bed out of contact with any copper surfaces to avoid the formation of cuprene.