Patent GB-811498-A (GB)
Title: Improvements in or relating to dilactones
Inventor: SAUER JOHN CARL
IPC: C07D307/34
Filed: 1955-05-10
Abstract: Dilactones having the structural formula <FORM:0811498/IV (a)/1> wherein one free valency in each ring is satisfied by R and the others by R1, and wherein R and R1 represent hydrogen, haloaryl, alkoxyaryl or hydrocarbon radicals free from non-aromatic unsaturation may be used as modifiers for polymeric resins, e.g. as plasticisers for vinyl chloride resins.  Specified radicals representable by R or R1 include methyl, octyl, dodecyl, phenyl, benzyl, cyclohexyl, methoxy-phenyl, dodecyloxy - naphthyl and chloro - naphthyl.  Tetrahydro - [2,21 - bifuran] - 5,51 - (2H,21H)-dione is given as an example, but numerous unsaturated dilactones from which the above compounds are obtained (see Group IV (b)) are listed.ALSO:The invention comprises unsaturated dilactones of the formula C8(RR1)2O4, wherein R and R1 represent hydrogen, haloaryl, alkoxyaryl or hydrocarbon radicals free from non-aromatic unsaturation, and wherein when R and R1 are different one of each is present in each lactone ring, the di-lactones yielding a suberic acid on hydrogenation with a platinum catalyst and showing strong absorption lines in the U.V. spectrum in the region of 3300 to 4400 and having specific absorption coefficients of 75 to 224.  The compounds exist in the cis and trans forms and when R and R1 are different positional isomers exist.  The dilactones are prepared by reacting an acetylenic compound R-C­C-R1, where R and R1 are as defined above, with carbon monoxide under at least 50 atmospheres pressure and at a temperature of 60-175 DEG  C., in the presence of a cobalt carbonyl catalyst and in an inert organic liquid free from active hydrogen.  Specified acetylenic compounds include acetylene, methyl-acetylene, 2-decyne, p-ethoxy or decyloxyphenyl acetylene, benzyl acetylene, cyclohexyl acetylene and others mentioned later in the examples.  Numerous suitable solvent media are listed.  The catalyst is a cobalt carbonyl, a reaction product thereof with an electron-donor solvent, e.g. a ketone or nitrile, or a compound which forms a cobalt carbonyl in the process, e.g. cobalt acetyl acetonate. The process, which may be effected continuously, yields cis and trans products which are separable by crystallization from methyl ethyl ketone.  The trans form can be converted into the cis form by crystallization from dimethyl formamide or by treatment with sulphuric acid, phosphoric acid, pyridine or a mixture of acetic acid and p-nitro aniline. The cis isomer can be obtained directly as principal product by carrying out the synthesis in the presence of hydrogen sulphide or a strong acid.  The unsaturated dilactones can be converted into the corresponding saturated dilactones by hydrogenation using a palladium catalyst which may be the metal or a compound thereof, e.g. the oxide, chloride or nitrate and may be in fluid or fixed bed state and, if desired, supported on a carrier. The unsaturated dilactones may also be hydrogenated in the presence of a platinum catalyst to yield a suberic acid.  Both hydrogenations may be effected in a solvent medium.  The unsaturated dilactones may be used as fungicides, e.g. in controlling tomato blight and as inhibitors of light-catalysed polymerization, e.g. of methyl methacrylate.  The saturated dilactones are useful as resin plasticizers (see Group IV (a)).  In examples: (1) acetylene is reacted with CO at 90-112 DEG  C. and pressures from 600-950 atmos. using cobalt carbonyl as catalyst and various solvent media such as acetonitrile, acetone, cyclohexanone, xylene, ethyl acetate and methyl pyrrolidone.  The product is treated with ether, filtered and the residue is crystallized from acetone, acetonitrile or ethyl acetate to recover the resulting [D 2,21(5H,51 -bifuran] -5,51-dione which may also be isolated by sublimation.  The product is mainly the trans dilactone and its isolation by crystallization from acetone and its conversion to the pure cis isomer by the above-mentioned methods is described.  The conversion of the unsaturated dilactone to the saturated dilactone, and saponification of the latter to the disodium salt of the corresponding dihydroxy dicarboxylic acid, and conversion of the unsaturated dilactone to suberic acid are also given in detail.  Further examples describe the preparation by the method of (1) of analogous compounds: (4) the bi-(phenyl furan) dione, a dyestuff (see Group IV (c)), from phenyl acetylene; (5) the bi-(n-butyl furan) dione from butyl-acetylene, and its hydrogenation to a suberic acid; (6) the bi-(diethyl furan) dione from hexyne-3; (12) the bi-(b -naphthyl furan) dione from b -naphthyl acetylene; (13) the bi-(p-chlorophenyl furan) dione from p-chlorophenyl acetylene; and (14) the bi-(o-methoxyphenyl furan) dione from o-methoxy phenyl acetylene.  Other examples (24) and (25) describe the preparation of the cis form of [2,21(5H,51H) - bifuran] - 5,51 - dione, by affecting the method of (1) in the presence of hydrogen sulphide, and its hydrogenation to the hexahydro-dilactone. According to the Provisional Specification the reaction may be carried out at elevated temperature and pressure utilizing any acetylenic hydrocarbon free from non-aromatic unsaturation, e.g. a dialkyl-acetylene or diphenyl acetylene.ALSO:The invention comprises the unsaturated dilactone - [D 2,21(5H,51H)- bi -phenylfuran)]-5,51- dione obtainable by reacting phenyl acetylene with carbon monoxide under a pressure of at least 50 atms. at a temperature of 60-175 DEG C. in the presence of a cobalt carbonyl catalyst in an inert organic liquid free from active hydrogen, this liquid being acetone in the Example (4). The compound exists in the cis-and trans-isomeric forms which are separable and the trans-isomer can be converted into the cis form by described methods (see Group IV (b)).  The dilactone dyes cellulose acetate, "Dacron" polyester fibre and "Orlon" acrylic fibre a yellow to orange colour using, for example, a dye-bath prepared by dissolving the dilactone in ethylene glycol monomethyl ether and diluting the solution with boiling water containing some acetic acid. The names "Dacron" and "Orlon" are Registered Trade Marks.