GB426519A - A process for the manufacture of chlorhydrins - Google Patents

Abstract

<PICT:0426519/IV/1> An aliphatic olefinic hydrocarbon is subjected in excess and preferably in a finely-divided state to the action of a finely-divided aqueous solution of hypochlorous acid. Mixtures of olefines with unreactive compounds, such as are obtained by cracking petroleum and shale oil, tars, pitches and asphalts and by the destructive distillation of brown coal, may be used, when the inert material serves to extract the products, if it is liquid, or if gaseous, is removed from time to time. The chlorhydrin is recovered by distillation. According to examples, ethylene, b -butylene, isobutylene, and mixed isobutylene and n-butane are treated in a reaction unit in which the air has been displaced by the respective olefines, so that the olefine is at all times in excess, with a spray, film or other finely-divided form of an aqueous solution of hypochlorous acid which is established outside the reaction chamber by known methods. A dispersing agent may be present in either or both the reacting fluids. The chlorhydrin mixture produced is drawn off, and a specified concentration of chlorhydrin and hydrochloric acid maintained in the circulating chlorine solution at all times by thus intermittently or continuously withdrawing a portion of the solution produced and replacing it by chlorine and water. In the accompanying drawing a spray chamber 1 is fitted with one or more atomizers 9 for the solution of hypochlorous acid, introduced through lines 8 communicating with vessel 7, and the air in reaction chamber 1 is replaced by gaseous or vapourized olefine, at any suitable pressure and temperature introduced directly and/or by bubbling through a quantity of aqueous solution of chlorhydrin and hydrochloric acid in the lower part of the chamber. A scrubbing tower 2 is provided with means 3 for introducing chlorine into the column, draw-off means 5 for removal of water-insoluble byeproducts, draw-off means 6 for removal of chlorhydrin, hydrochloric acid and water. Fresh water is introduced at 13 and initially in tank 7, whence pump 11 provides for the circulation of the hypochlorous acid through the spray chamber where it meets the olefine from lines 14, and returns through the tower 2 to the tank 7. The necessary filters, pumps and means for adjusting the temperature and pressure are included. Further specified olefines suitable for the conversion to the chlorhydrin include propylene, amylenes, butylenes, allene, butadiene, isoprene, butane-butene and other fractions from the cracking of petroleum products and generally tertiary olefines and those which can be maintained in a state of vapour at a temperature and pressure at which the free hypochlorous acid does not decompose. Specifications 265,259, [Class 2 (iii)], and 377,595 are referred to.