Patent GB-453147-A (GB)
Title: A process for the production of hydrated olefines
IPC: C07C29/04
Filed: 1935-03-05
Abstract: <PICT:0453147/IV/1> Olefines are catalytically hydrated at a temperature above 100 DEG  C. and under a super-atmospheric pressure in the presence of liquid water and an acid reacting catalyst, the process being characterized in that the hydration is effected in a converter which is constructed of or lined with a metal whose normal electrode potential is between + 0,2 and -0,4 on the scale in which the normal electrode potential of hydrogen is 0, or with an alloy predominating in such metals, such as copper and alloys thereof.  The invention is particularly useful in catalytic hydrations where the catalyst is dilute sulphuric acid, but favourable results are also obtained with organic sulphonic acids, phosphoric acid, hydrochloric acid, boric acid and acetic acid. In addition to the use of free acids, the presence as catalysts of sulphates, acid sulphates, halides, nitrates, phosphates, and pyrophosphates is mentioned. Metals which may be present in the form of their sulphates in the catalytic solution are beryllium, magnesium, zinc, cadmium, aluminium, manganese, chromium, cobalt and nickel.  It is stated that the presence of the above sulphates in addition to the free acid has the effect of reducing the amount of polymerization of the olefines. The preferred temperature range is 100--374 DEG  C.  Pressures which may be used vary from slightly above the vapour pressure of water at the operating temperature to as high as 10,000 lbs. per square inch. The concentration of the acid is always less than 15 per cent and preferably less than 5 per cent.  Water is added in the liquid phase in amount at least equal to that used in the reaction, the rate of addition being adjusted to maintain constant the volume and concentration of the acid catalyst.  The process of the invention is applicable to normal, secondary, and/or tertiary olefines, preferably those which are normally gaseous such as ethylene, propylene, butene-1, butene-2, and gamma butene.  Pure olefines or mixtures of olefines may be used.  If desired the tertiary olefine content may be first selectively removed prior to the hydration.  The olefines may be heated prior to introduction into the converter by the method of heat exchange.  In an example, a mixture of olefine, paraffin hydrocarbons and water are mixed in 1, heated in the heat-exchanger 2, passed through line 3 to heater 4.  The vapours mixed with liquid water next pass to the converter 5 lined with copper through a perforated copper pipe at the bottom.  The operating temperature is 225 DEG  C. and the pressure 3000 lbs. per square inch.  The catalyst is 5 per cent sulphuric acid.  The hot reaction products leave the reaction chamber 5, pass through the heat-exchanger 2 and thence to a pressure condenser 6.  The material in the liquid state flows past a control valve 8 into a receiver 10.  The converter is filled to a predetermined level with acid catalyst and maintained at this level by an automatic electric levelling device 16.  This consists of a platinum rod 18 passing through the top of the converter enclosed in a water-cooled pressure fitting into contact with the surface of the catalyst, and insulated from the converter.  The wall of the converter and the platinum rod form respectively the terminals from the battery 19.  When the level of the catalyst falls, the circuit is broken.  This actuates an electric relay 20 which in turn controls a high pressure liquid pumping system 17 which forces water in to replace that which has been used in the reaction.