Patent GB-839437-A (GB)
Title: Unsaturated dilactones, their manufacture and the preparation of a dibasic acid therefrom
IPC: C07D311/10
Filed: 1957-02-27
Abstract: Unsaturated dilactones of the formulae <FORM:0839437/IV (b)/1> or <FORM:0839437/IV (b)/2> and generally other oxygen containing compounds such as coumarin and polymers of the general formula (C3H2O)x where x is from 3 to 6, are prepared by reacting carbon monoxide with acetylene at elevated temperature and an elevated pressure of up to 28 atmospheres gauge in the absence of water or other compounds having a replaceable hydrogen atom combined with a hetero atom, in the presence of a cobalt catalyst composed of a cobalt carbonyl and/or a cobalt carbonyl hydride and/or a salt thereof and/or metallic cobalt and/or a cobalt compound (other than the carbonyl compounds), from which cobalt carbonyls are formed by reaction with CO under the reaction conditions, as one ingredient and an organic non-cobalt containing compound forming a complex compound with carbonyls and containing no heterogeneously combined replaceable hydrogen atoms as the other ingredient, the organic complex forming compound being a member of the group consisting of mono- and di-nitriles, saturated aliphatic open-chain or cyclic ketones, esters of mono- and polybasic carboxylic acids, N-disubstituted carboxylic amides, lactones, lactams, acetylene and other unsaturated hydrocarbons, and ethers including open and cyclic ethers and acetals, and numerous examples of such complexformers are given. These complex-formers may be used in the stoichiometric proportions or less, or excess may be present as a solvent.  Other inert solvents may be present. The complexes may be formed in situ.  The preferred cobalt compounds are the octa carbonyl and polymeric tricarbonyl. The catalyst may be used in a rigidly arranged form, for example on a carrier.  The reaction may be effected at 40-100 DEG  C. under pressures of about 5 to 28 atmospheres, and batchwise or continuously.  The acetylene and CO are generally used in equi-volume amounts and may contain inert diluents.  The dilactones are formed as a cis-trans isomeric mixture which may be separated.  The so-obtained or obtainable lactones as a mixture or as individual isomers may be converted into suberic acid by catalytic hydrogenation, preferably using a metal of Group VIII or a compound thereof as catalyst, such as platinum oxide, palladium, nickel or cobalt; by-products including the corresponding saturated dilactones and butyro lactonebutyric acid are further reduced to suberic acid by means of stannous chloride or by treatment with aqueous HI at elevated temperature, suitably at 160-180 DEG  C. in a closed vessel.  The hydrogenation may be effected at room or elevated temperature, and if desired, in the presence of a solvent and under raised pressure.  Examples 1-6 describe the preparation of the cis- and trans-unsaturated dilactones and the isolation of the cis-trans isomeric mixture of the dilactones, polymeric materials (C3H2O)3-6, coumarin and various polymeric residues, by a series of fractional distillations, solvent extractions and crystallizations.  The cis- and trans-isomers are separated by fractional crystallization from acetone or by sublimation.  In Example 7, a cis-trans mixture of the unsaturated dilactones in tetrahydrofurane is catalytically hydrogenated using a Pd catalyst and the product comprising suberic acid, after removal of solvent and catalyst is further reduced by means of aqueous HI; (8) the same dilactone mixture is catalytically hydrogenated using PtO in glacial acetic acid, the catalyst and solvent are then removed, the suberic acid residue is extracted with ethyl acetate and the extract further reduced by means of aqueous HI. Specifications 708,593 and 811,498 are referred to.