Patent GB-566868-A (GB)
Title: Improvements in and relating to the production of dicarboxylic acids
IPC: C07C51/12
Filed: 1943-05-06
Abstract: Aliphatic dicarboxylic acids are prepared by reacting at elevated temperature and pressure, carbon monoxide and water with an olefinic or hydroxy aliphatic carboxylic acid, an ester thereof, or a compound or compounds giving rise to such an acid or ester under the conditions of the reaction, the olefinic linkage or hydroxyl group of such an acid or ester being separated from the carboxyl carbon by a chain of at least two contiguous carbon atoms, the reaction being carried out in the presence of a catalyst comprising a halogen compound of an amphoteric element or of an element, the oxide of which on hydrolysis forms a weak base, the said base forming a complex with alcohols, ethers or esters.  In addition, the catalyst may be sulphuric, hydrochloric, phosphoric, boro-phosphoric or boro-tungstic acid.  Crude carbon monoxide may be employed, but should be freed from objectionable constituents such as sulphur compounds, metallic carbonyls, carbon dioxide, oxygen.  Inert gases, such as nitrogen, in the carbon monoxide is sometimes desirable as an acid in modifying the reaction rate.  The preferred operating carbon monoxide pressure range is between 400 and 1000 atmospheres and temperatures between 75 DEG  and 300 DEG  C. are employed, dependent on the nature of the starting materials employed.  Suitable aliphatic monocarboxylic acids specified are oleic, undecylenic, erucic, elaidic, petroselinic, brassidic, isoerucic, ricinoleic, linoleic, abietic, oleostearic, or their esters, anhydrides or salts. Compounds which are functionally capable of dehydration or rearrangement to give the desired olefinic or hydroxy acids are also suitable; thus, the hydroxy acids, such as those obtainable by hydrolysis of hydrogenated castor oil (presumably 12-hydroxy stearic acid) or hydrogenated oiticica oil (presumably 14-hydroxy stearic acid), 10-hydroxy stearic acid, 9.10-dihydroxy stearic acid, and lactones such as gamma-butyrolactone, delta valerolactone, and stearolactone may be used.  Catalysts in addition to those already specified are the following anhydrous metal and non-metal halides: titanium, antimony, boron, aluminium, beryllium, zirconium, hafnium, thorium, columbium, sulphur, silicon, phosphorus, tantalum, chromium, vanadium and molybdenum halides.  When using boron trifluoride as catalyst, the interior of the reaction vessel should be protected against corrosion, the products of which may have an inhibitory effect; glass-lined apparatus, use of and resistant alloy steels containing for example high proportions of molybdenum, cobalt, tungsten, chromium, manganese or nickel, or plating of the inner surfaces with chromium or silver are mentioned.  The dibasic acids may be separated by converting them into readily distillable esters and purifying by fractionation, by subjecting the acids to fractional precipitation, by crystallisation of the metallic salts or of the free acids in those cases in which solid crystalline products are obtained. These dibasic acids are useful in the preparation of polymeric condensation products such as polyamides which are valuable as coating compositions, textile fibres and the like and also alkyd resins useful as protective coating compositions.  In examples: (1) oleic acid, boron trifluoride and water in the molecular ratio of 3 : 1.03 : 2.6 are heated in the presence of carbon monoxide at 400 atmospheres pressure and at 150-159 DEG  C. resulting in a 30 per cent conversion of oleic acid to dibasic acid; (2) the same starting materials in the ratio 3 : 1.2 : 3 are similarly treated at 700-800 atmospheres pressure with carbon monoxide and the dibasic acid isolated by formation of the methyl ester and its subsequent saponification.  Spinnable polyamides are prepared from the dibasic acid by heating with decamethylene-diamine and also hexamethylenediamine.  A spinnable polyamide is also obtained by preparing a 50 : 50 interpolymer of the dibasic acid and hexamethylene-diamine with hexamethylene diammonium adipate; (3) methyl 12-hydroxystearate, water and boron fluoride are reacted under similar conditions yielding mainly methyl carboxystearate.