GB409676A - Improvements in or relating to the hydration of olefines - Google Patents

Abstract

The hydration of olefines not higher than hexylene to produce alcohols and ethers is effected by the successive or simultaneous action of an acid containing at least 5 per cent of an ester of an inorganic acid (or organic-inorganic acid such as a sulphonic acid) and of water or water vapour. The acid may be a strong mineral acid of low volatility such as sulphuric or phosphoric acid or a sulphonic acid, and the ester may be a sulphuric or phosphoric ester of a glycol or polyhydric alcohol or higher hydroxy fatty acid but not an unsubstituted alkyl ester of a mineral or sulphonic acid in which the alkyl group contains not more than six carbon atoms. Suitable esters are glycol monosulphate, glycerol sulphates, hydroxystearosulphuric acid, sulphoricinoleic acid, sulphoaromatic acids (Twitchell reagents) and glycol and glycerol phosphates. When the esters contain free acid groups they may be used without any other acid. The olefine may be absorbed in the ester-containing acid, the product being subsequently hydrolyzed or the olefine may be caused to react continuously with water or water-vapour and with the ester-containing acid while the hydration products are continuously removed for instance by distillation. For the two-stage process sulphuric acid of 60--90 per cent may be used containing 5--40 per cent of ester, the temperature being 60--80 DEG C. for the absorption of ethylene, but lower temperatures may be used for homologues of ethylene. When mixtures of olefines are employed, absorbent solutions of increasing concentration and-or temperature may be used. The absorption may be effected under pressure for instance up to 5 atmospheres, and the acid may contain in addition to the ester, catalysts such as calcium, lead, iron, ferrous-ammonium or mercurous sulphates or silver or copper. When a continuous process is employed the temperature may be 100--350 DEG C. and the pressure may be up to 25 atmospheres; the gases may be passed in finely-divided form into the acid liquor or may meet it in counter-current in a tower. For the production of ether, the ethylene should be present in at least twice the quantity of the water vapour, but for alcohol equimolecular quantities may be employed. The gases may be preheated for instance to 150 DEG C. The ethylene mixed with a small quantity of water may be introduced into ester-containing sulphuric acid of 50--60 per cent strength, liquid water being added as required to maintain the concentration constant. In examples: (1) ethylene is passed into 90 per cent sulphuric acid containing 5 per cent of glycol monosulphate and 10 per cent of sulphoricinoleic acid, at 79 DEG C. and 2 atmospheres pressure; the absorption liquor is finally diluted with 3 times its weight of water and boiled, ethyl alcohol being separated for instance by fractionation; (2) a mixture of lower olefines from an oil-cracking plant is freed from sulphur compounds and led up a tower in counter-current with 50 per cent sulphuric acid containing 5 per cent of hydroxystearosulphuric acid and 5 per cent of sulphoaromatic stearic acids at 20 DEG C. whereby the more reactive olefines are absorbed and may be recovered as alcohols by hydrolysis; the remaining gases, mainly ethylene and propylene are passed up a tower in countercurrent with 70 per cent sulphuric acid containing 15 per cent of sulphoaromatic stearic acids and 5 per cent of hydroxystearosulphuric acid, the tower being maintained at 180 DEG C. by means of a heating-jacket; the vapours leaving the top of the tower are condensed to recover alcohols and hydration products.