Preparation of Dialkyl Sulphates

As is known, the pyrosulphates of alkalies, such as sodiun pyrosulphate, can be manufactured according to various methods. The cheapest way of making sodium pyrosulphate, for example, which is a very cheap raw material, is to heat sodium bisulphate in vacuo. The pyrosulphates can also be made by combining sulphur trioxide with a sulphate, such as sodium sulphate. Similarly the chlorosulphonates of alkalies can be made by combining sulphur trioxide with a chloride, such as sodium chloride. 

228 parts of sodium pyrosulphate and 92 parts of alcohol are mixed at ordinary temperature for 1—2 hours, then heated under a reflux condenser at 80°—100° C. for a further 4—5 hours, the diethyl sulphate so formed being distilled off in vacuo. A high yield of diethyl sulphate can be thus obtained. 

Alcohol vapour may be passed over sodium pyrosulphate heatecj to about 150° C. If reduced pressure is maintained in the apparatus tl ie diethyl sulphate will distill off as fast as formed, together with any excess of alcohol. The diethyl sulphate can be isolated in any known or suitable way. 

It is to be understood that I do not confine myself to any particular methods or details of working, and that the manner carrying the invention into effect can be varied within wide limits. 

The sodium pyrosulphate may he used in the proportion of aboui two molecules to two molecules of alcohol or of about one molecule of tlx pyrosulphate to one molecule of ether. I do not confine myself t( employing the materials in these proportions but may use the alcohol o ether in excess, or otherwise vary the proportions. 

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