Patent GB-760364-A (GB)
Title: Improvements in the production of oxygen-containing organic compounds
IPC: C07C51/12
Filed: 1954-06-09
Abstract: Oxygen-containing organic compounds especially carboxylic acids and their functional derivatives are obtained by catalytic reaction of aliphatic alcohols, esters, or ethers with carbon monoxide, if desired in the presence of hydrogen, at raised temperature and pressure using a catalyst which contains besides iron and halogen in free or combined form, also hydrazine, a polyamine or a quaternary organic ammonium, phosphonium, arsonium or stibonium compound.  The catalyst may be used in the form of a ready-made complex but it is preferred to use the components which form the catalyst.  The iron may be made available by using iron metal or iron alloys, preferably in powdered form, inorganic or organic iron salts such as ferric carbonate, ferrous sulphide, iron disulphide, ammonium ferric alum, ferrous sulphate, ferric cyanide, ferric-formate, -acetate, -citrate, or -oxalate, iron halides, iron carbonyls and their derivatives such as iron carbonyl hydride, and their salts, and complex iron conpounds such as potassium ferrocyanide, potassium ferricyanide, ferro hexahydroxy sulphate Fe(OH)6SO4 and ferro hexa-acetonitrile chloride Fe(CH3CN)6Cl2.3H2O.  As the halogen component of the catalyst it is preferred to use iodine or bromine or both together, either in the form of the elements or in the form of their compounds, e.g. halogen hydracids, metal halides, or organic halogen compounds, e.g. alkyl halides.  The third main component of the catalyst may be introduced as a salt preferably as a halide of a quaternary organic ammonium, phosphonium, arsonium or stibonium compound which is either introduced as such or allowed to form during the carbonylation from organic amines, phosphines, arsines or stibines, and compounds suitable for the formation of onium salts, e.g. alkyl or aralkyl halides.  In some cases the addition of alkyl halides is not necessary since when alcohols are used in conjunction with halogen hydracids, e.g. hydriodic acid, they may be formed "in situ."  The reaction is preferably carried out at 200-300 DEG C. and at pressures of at least 50 atmospheres, e.g. between 200 and 700 atmospheres. Hydrogen may be added but it is preferred to use an excess of carbon monoxide, e.g. a ratio of CO : H2 of at least 70 : 30.  The process may be carried out continuously or discontinuously and when working continuously the feed, catalyst, and carbon monoxide or gas containing carbon monoxide may enter the reaction vessel at its lower end and product discharge taken from the upper end or the starting material and catalyst may be introduced at the upper end and the gas at the lower end, the product being withdrawn through a siphon at the lower end of the vessel.  The starting material or the reaction product may be used as solvent or water, dioxane, hydrocarbons, or amides may be used as solvent.  The reaction products are generally carboxylic acids or esters, or carboxylic acid anhydrides when working in the absence of water.  By increasing the hydrogen content of the carbon monoxide aldehydes and their derivatives may also be formed.  In examples: (1) acetic acid containing a small amount of methyl acetate is obtained by reacting methanol in an autoclave, filled with nitrogen, with carbon monoxide containing a small amount of hydrogen in the presence of a mixture of iron pentacarbonyl, iron acetate, iodine, and triphenylethyl phosphonium iodide, the reaction being carried out at 275 DEG  C. and 300 atmospheres pressure; (2) as in (1) except that trimethyl ethyl ammonium iodide is used instead of triphenylethyl phosphonium iodide; (3) as in (1) except that ethylene diamine is used instead of the phosphonium iodide and the reaction temperature is 285 DEG  C., a higher proportion of methyl acetate being obtained in this case.