Improved production of alcohols and/or esters

摘要

Carboxylates of lead, cadmium or copper, or mixtures thereof, are reduced so as to give the corresponding alcohols, or esters thereof with the carboxylic acids, in a continuous process in which hydrogen is brought, at elevated temperature and pressure, into intimate contact with the molten carboxylate by passing excess of turbulence or by using the molten carboxylate in finely divided form or in the form of thin films. When unsaturated carboxylates are used, the products may contain a smaller number of unsaturated bonds than the starting material. With lead and copper carboxylates, the products are mainly alcohols, while with cadmium carboxylates the esters are the main product. Saturation tends to occur when unsaturated copper carboxylates are employed as starting material. Carboxylates of metals other than those of copper, cadmium and lead may be present, e.g. those of nickel and chromium. In the examples: (1) lead soaps of coconut oil fatty acids prepared by agitating and heating the acids with litharge are introduced in molten condition into the apparatus shown in Fig. 1 by means of pump 11. They are further heated in the bottom of the reaction chamber 13. Hydrogen is continuously applied at a fast rate and under high pressure into the reaction vessel, via the preheater 14 and beneath the surface of the carboxylates. The reactants and reaction products move upwards in the chamber 13 through holes 18 and 19 in the baffles 16, the products finally passing into the high-pressure receiver 23, the gaseous materials being passed through condenser 24 and trap 27 and finally recycled. The product is collected in tank 28 after cooling by means of cooling coils within receiver 23 or by flash evaporation of the water present on reduction to atmospheric pressure. Molten lead formed in the reaction is removed through outlet 20 and may be used to prepare more lead oxide; (2) molten lead soaps of coconut oil acids are preheated and sprayed in finely divided form into vessel 113 of the apparatus shown in Fig. 2 through the spray nozzle 117. Hydrogen is introduced under high pressure via the preheater 114. The liquid products are collected in the high pressure receiver 126, which may contain a cooling coil, whilst the gases pass through the trap 123 and condenser 124 and are recycled. The product is collected in tank 128, molten lead being removed through outlet 120; (3) molten cupric soaps of coconut oil fatty acids are caused to flow in thin films over vertical surfaces and sloping baffles in contact with preheated hydrogen under high pressure. The products contain finely divided copper which settles out; (4) and (5) similar processes to that of example (1) are carried out using cadmium stearate and lead benzoate respectively; (6) a similar process to that of example (3) is carried out using lead soaps of coconut oil fatty acids. Other methods of ensuring intimate contact of the reactants may be used such as mechanical agitation. Higher fatty alcohols prepared by this process may be sulphated or sulphonated for use in detergents, wetting agents or emulsifying agents. Alcohols or esters prepared from rosin acids or fatty acids derived from drying oils may be used to prepare drying compositions for use in p paints and varnishes. Synthetic waxes and plasticisers may also be prepared. Specifications 562,609 and 562,610 are referred to.