Patent GB-766151-A (GB)
Title: Improvements in oxidative alkaline fusion of organic compounds
IPC: C07C37/04
Filed: 1953-04-20
Abstract: Aliphatic organic compounds susceptible of being oxidized by alkali fusion are subjected to oxidative alkaline fusion by (a) charging the compound and an effective amount of a strong base, both of these compounds being in finelydivided form, into an enclosure, at least stoichiometric amounts of water being present in the <PICT:0766151/IV(b)/1> <PICT:0766151/IV(b)/2> enclosure when water is necessary in the oxidation reaction; (b) introducing an elastic fluid substantially simultaneously into the enclosure to produce a fine suspension of the contents of the enclosure; and (c) heating the contents to an elevated temperature.  Specified aliphatic compounds are unsaturated aliphatic carboxylic acids, such as crotonic acid, tiglic acid, angelic acid, undecylenic acid, oleic acid, and ricinoleic acid; aliphatic mercaptans such as propyl-, heptyl-, hendecyl-, and heneicosyl mercaptans, unsaturated mercaptans, e.g. oleyl and undecylenyl mercaptan, dimercaptans, and the corresponding thioethers, e.g. diheptyl thioether.  The esters, amides and other functional derivatives of the unsaturated acids may also be used. The aliphatic compound may be used in the form of a salt thereof with a strong base.  When water is required for the reaction it can be injected into the enclosure in the form of steam, this steam then serving to provide water for the reaction and as the elastic fluid. The steam, e.g. superheated steam, may also serve as the source of heat for the reaction which may be carried out at a temperature within the range of about 180 DEG  to 425 DEG  C.  If necessary, a catalyst comprising a metal or metal compound of Groups IV or VIII of the Periodic Table or mixtures of said metals or metal compounds may be added to the charge.  Such catalysts are necessary in the oxidation of mercaptans or thioethers.  The strong base may be an alkali or alkaline earth metal oxide, hydroxide, or carbonate, or a quaternary ammonium hydroxide.  It is preferred to use an alkali metal hydroxide and it is advantageous to use an excess of the base, e.g. about 1.4 to 4 times the stoichiometric amount.  Where the organic compound is capable of salt formation and reacts as such, sufficient additional base should be present in the reaction charge for the in situ conversion of the organic compound into its salt. Steam is the preferred elastic fluid but inert gases, e.g. nitrogen, may be used instead of or in addition to steam when the reaction mixture contains sufficient moisture for the reaction.  The reaction charge may be prepared by premixing the reactants and then reducing the mixture to finely-divided form or the reactants can be introduced separately, in finelydivided form, into the reaction enclosure.  The maximum satisfactory particle size is about 10 microns, the preferred range for the size of the particles being 2 to 8 microns.  In the case of liquid reactants it is desirable to introduce them into the reaction zone via nozzles which break the liquid up into a fine mist. The process may be carried out in the apparatus shown in Fig. 1, in which the direction of flow of reactants and products is indicated by arrows.  The reactants, when solid, are charged to hopper 13 and are charged to the reactor by means of an elastic fluid such as superheated steam which is injected into the upper end of inlet pipe 11 which is provided with a venturi 12.  Heated elastic fluid which may be superheated steam and/or an inert gas is charged through pipe 14 into manifold 15 from which it passes through nozzles 16 and impinges in the form of jets on the reactants charged through pipe 11, thus directing the reactants up leg 10 and creating conditions of turbulence which promote the reaction. A liquid such as water may be injected through pipe 17 to control the temperature.  The apparatus is arranged to provide a cycle including a return leg 18 near the top of which a series of baffles may be provided as indicated at outlet 19.  The reaction mixture passes out of leg 18 through the outlet 19 and then to a cyclone and condenser 20.  When one of the reactants is a liquid there may be more than one inlet pipe 11 and when the mixture of reactants is liquid a metering device can be used to introduce the reactants.  In one embodiment the leg 18 may be blocked off below the outlet 19 as indicated at 22 so that the entire reaction mixture leaves the apparatus in one pass through the reaction zone via outlet 19.  The grinding of solid reaction mixtures can be effected in the apparatus and a suitable arrangement for use in continuous operation comprises two or more of such apparatus mounted in series, the first being used for grinding the reaction mixture and the subsequent apparatus being used for effecting the desired reaction.  A simpler apparatus (Fig. 2), comprises a feed-pipe 111 and an upright tube 181 for feeding solids or liquids or both and a side tube 141 for admitting heated elastic fluid, the lower end of tube 181 being connected by a U-coupling to an upright reaction tube 101 the top of which is provided with a connection 211 for discharge of the reaction products to a cyclone and condenser. The heated elastic fluid passes through nozzles 161 and impinges on the reactant particles and sweeps them up the reaction leg 101.  The reaction products may, if desired, be recycled through a second similar reactor.  Examples are given for the oxidation of sodium crotonate with sodium hydroxide to form sodium acetate; of the alkali metal salts of tiglic acid and angelic acid to the corresponding salts of acetic and propionic acids; of undecylenic acid with potassium hydoxide to form potassium pelargonate and potassium acetate, of oleic acid with potassium hydroxide to form potassium palmitate and potassium acetate, of methyl ricinoleate with sodium hydroxide in the presence of water to form sebacic acid and capryl alcohol; of technical potassium ricinoleate and potassium hydroxide to yield sebacic acid and capryl alcohol; of barium ricinoleate with barium hydroxide to yield the same products, of sodium ricinoleate and solid sodium hydroxide to yield omega-hydroxydecanoic acid, sebacic acid, methyl hexyl ketone and capryl alcohol using heated nitrogen as the elastic fluid; of sodium ricinoleate with anhydrous sodium carbonate to yield sebacic acid and capryl alcohol; and of sodium ricinoleate with sodium hydroxide to yield sebacic acid and capryl alcohol, the ricinoleatesodium hydroxide mixture being melted under vacuum and charged to the apparatus of Fig. 1 through fog-type nozzles located in the inlet pipe 11.  Apart from the above example in which nitrogen is used, superheated steam is used in each case as the elastic fluid for injection into the reactor. In another example, dodecyl mercaptan is oxidized with sodium hydroxide in the presence of finely ground nickel-tungsten sulphide as catalyst to yield sodium laurate, the reactants being introduced separately in finely-divided form into a copperlined apparatus of the type shown in Fig. 2, whilst superheated steam is charged to the reactor and serves as the source of heat.  Other mercaptans and thioethers in which the sulphur atom is attached to an aliphatic carbon atom or atoms may be oxidized similarly.  The mercaptans may be substituted by an alicyclic, aromatic or alkoxy group or by a halogen atom, a nitro group, an amino group or an alkyl amino group.  If more than one mercapto group is present polycarboxylic acids are produced.  Specified carboxylic acids which may be obtained from mercaptans by the process of the invention are butyric, valeric, trimethyl acetic, caproic, heptanoic, caprylic, pelargonic, capric, undecanoic, lauric, tridecanoic, myristic, pentadecanoic, palmitic, margaric, stearic, nonadecanoic, arachidic, adipic, tetradecanedioic, 4-tetradecenoic and oleic acids. The reaction of diheptyl thioether by fusion with sodium hydroxide in the presence of molybdenumnickel sulphide as catalyst to form sodium heptanoate is also referred to.  Specification 678,568 is referred to.