Patent GB-324897-A (GB)
Title: Improvements in or relating to process and apparatus for the hydration of olefines
IPC: C07C29/04
Filed: 1928-11-01
Abstract: 324,897. Carpmael, A., (I. G. Farbenindustrie Akt.-Ges.). Nov. 1, 1928. Secondary and tertiary alcohols; ethylene.- Secondary and tertiary alcohols, for example, isopropyl and isobutyl alcohols, are produced by causing higher homologues of ethylene to react with a dilute acid or aqueous salt solution having an acid reaction, in the presence of a catalyst comprising one or more compounds of bismuth or of a heavy metal of the first group of the periodic table. The reaction is carried out at temperatures between 100‹ C. and 250‹ C., and at a partial pressure of the higher homologue of ethylene not substantially less than 10 atmospheres. Catalysts specified are bismuth chloride, bismuth oxychloride, cuprous chloride, copper sulphate, copper phosphate, copper p-toluenesulphonate, copper naphthalenedisulphonate, silver sulphate, and silver naphthalenedisulphonate. As dilute acids, hydrochloric, sulphuric, or phosphoric acid, or organic sulphonic acids such as p-toluenesulphonic or naphthalenedisulphonic acid may be employed, preferably at a concentration below 3 mols. per litre. As starting material, industrial gases containing propylene, butylene, amylene, &c. may be used, if necessary after concentration by partial liquefaction or other suitable method. The process may be used to enrich gases containing ethylene and higher homologues in their ethylene content, the residual gases after the removal of the higher homologues being used for the production of pure ethylene derivatives such as ethylene glycol. In carrying out the process, the olefinic gases may be forced by stages into an acid-proof autoclave containing the dilute acid and catalyst, and after cooling and allowing the pressure to decrease, the alcohol or alcohols may be recovered by distillation in the form of their azeotropic mixtures with water; or the process may be made continuous by introducing the gases into the reaction space, the temperature of which is so adjusted that the alcohols produced and the non-reacting gases escape continuously. In another method, the dilute acid containing the catalyst is caused to flow in countercurrent to the gases, at a pressure greater than the vapour pressure of the liquid at the temperature employed. The liquid containing the alcohols produced is then drawn off and replenished by the corresponding quantity of fresh dilute acid and catalyst. In carrying out the process by means of the apparatus shown, propylene is forced through a pipe 7 and valve 7<1> into a tubular steel chamber 1 lined with silver, the lower part of which contains dilute sulphuric acid maintained at a temperature of 220‹ C. by means of an electric resistance heater 2. Water is supplied through the pipe 12 and valve 12' at the rate at which it is consumed. Vapours of water and of the isopropyl alcohol produced are rectified in the upper part of the tube 1, which is packed with a filling material such as Raschig rings, and pass to a reflux condenser 4, the temperature of which is regulated so that vapours rich in isopropyl alcohol escape to a receiver 5, where they are condensed, and drawn off through a valve 11. The excess propylene passes through a pipe 8 and is returned to the chamber 1 by means of a circulating pump 9. Should the gas contain inert constituents, these are finally led off through a pipe and valve 10. 3, 3<1> are thermocouples assisting control of temperatures in the chamber 1. 6 is a manometer. Silver sulphate may be added to the dilute sulphuric acid in the chamber 1, if traces of silver dissolved by the acid from the lining of the vessel are insufficient to promote the reaction.