Patent GB-1082808-A (GB)
Title: Cyclobutanes
Filed: 1964-11-25
Abstract: As co-monomers in the manufacture of fibre- and film-forming polymers, use is made of cyclobutanone or cyclobutanol derivatives of either of the formulae <FORM:1082808/C3/1> or <FORM:1082808/C3/2> in which the substituents R2, taken singly, are alkyl groups of 1-8 carbon atoms or, taken collectively with the carbon atom to which they are attached, denote a saturated carbocyclic ring of 4-8 carbon atoms, each of the substituents R3 may be hydrogen or a halogen atom or an alkyl group of 1-8 carbon atoms and the substituents R4, taken singly, may be hydrogen or halogen atoms or alkyl groups of 1-8 carbon atoms or, taken collectively with the carbon atoms to which they are attached, denote an unsaturated carbocyclic ring of 4-8 carbon atoms (see Division C2).  Thus, the compounds may be co-polymerized with one or more polymerizable vinyl monomers or the cyclobutanols may be esterified with dicarboxylic acids to yield difunctional monomers useful for cross-linking resins.  Examples are given of the polymerization in aqueous medium of 2 - butyl - 2 - ethyl - 3 - vinylcyclobutanol and 2 - butyl - 2 - ethyl - 3 - vinylcyclobutanone with acrylonitrile in the presence of sodium lauryl sulphate and ammonium persulphate. The polymers obtained can be spun into fibres from dimethylformamide solutions.ALSO:The invention comprises compounds of the formula <FORM:1082808/C2/1> in which the substituents R2, taken singly, are alkyl groups of 1-8 carbon atoms or, taken collectively with the carbon atom to which they are attached, denote a saturated carbocyclic ring of 4-8 carbon atoms, each of the substituents R3 may be hydrogen or a halogen atom or an alkyl group of 1-8 carbon atoms and the substituents R4, taken singly, may be hydrogen or halogen atoms or alkyl groups of 1-8 carbon atoms or, taken collectively with the carbon atoms to which they are attached, denote an unsaturated carbocyclic ring of 4-8 carbon atoms.  The compounds are obtainable by reacting a dialkyl ketene with a conjugated diene.  Suitable dialkyl ketenes include dimethylketene, dipropylketene, dioctylketene, pentamethyleneketene, ethylbutylketene and di(2-ethylhexyl)ketene. Suitable conjugated dienes include 1,3-butadiene, isoprene, piperylene, vinyl-1-cyclohexene, chloroprene, propenyl-1-cyclo-octene and 2-(tert.-butyl)-1,3-butadiene. In typical examples, (1) butylethylketene and 1,3 - butadiene yield 2 - butyl - 2 - ethyl - 3-vinylcyclobutanone and, as a by-product, 2,4-dibutyl - 2,4 - diethyl - 1,3 - cyclobutanedione, (2) butylethylketene and isoprene yield a mixture of isomeric 3-substituted-2-butyl-2-ethylcyclobutanones, and (3) ethylisobutyl-ketene and chloroprene yield 2-ethyl-2-isobutyl-3-(1-chlorovinyl)cyclobutanone. Other specified products include 2,2-dibutyl-3-(2-methylpropenyl)-cyclobutanone, 2 - butyl - 2 - ethyl - 3 - (1-cyclohexenyl)cyclobutanone and 1-oxo-3-vinylspiro-(3,5)-nonane. The invention also comprises products of the formula <FORM:1082808/C2/2> in which R2, R3 and R4 are as specified above. These compounds are obtainable by treating a compound of the first formula above with a reagent which reduces the keto group but does not reduce the double bond.  Specified reducing agents of this kind are metal hydrides, e.g. lithium hydride, lithium aluminium hydride or sodium or potassium borohydride, aluminium alkoxides, e.g. aluminium isopropoxide, and metallic sodium in ethanol.  Examples are given of the reduction of 2-butyl-2-ethyl-3-vinylcyclobutanone, 2 - ethyl - 2 - butyl - 3-propenylcyclobutanone, 2 - ethyl - 2 - isobutyl-3 - (1 - chlorovinyl)cyclobutanone and 2,2-dibutyl - 3 - (1 - butenyl)cyclobutanone with lithium aluminium hydride.  The products are useful as comonomers in the preparation of copolymers (see Division C3).