Patent GB-796133-A (GB)
Title: Improvements in or relating to unsaturated bicyclic compounds and their polymers
Inventor: ROSE JOHN BREWSTER
IPC: C07C31/27
Filed: 1955-03-21
Abstract: The Specification comprises compounds represented by formul  (1) and (2): <FORM:0796133/IV (b)/1> <FORM:0796133/IV (b)/2> in which X represents -H or -CH3 and in formula (1) Y represents -CH2CH2-; -O-; or -CO-O- and in formula (2) Y represents -CH2-; -CH2-CH2-; or -O-. These compounds can be polymerized or copolymerized (see Group IV (a)).  The monomeric compounds can be prepared by formation of the 2- and 3-methylene groups from the corresponding compounds containing substituted 2- and 3-methyl groups -CH2Z, where Z may be Cl, Br, I, OH or OCOR, R being an alkyl group preferably methyl, by removal of HZ.  When Z is OH, dehydration can be carried out by heating in the presence of a catalyst such as alumina, aluminium silicate, phosphoric acid on silica gel, or silica-alumina, at a temperature between 65 DEG  and 150 DEG  C.  When Z is halogen, dehydrohalogenation can be performed by heating under reflux with alcoholic caustic alkali.  When Z is acyloxy the desired compound can be formed by pyrolysing the acyloxy derivative at a temperature between 450 DEG  and 550 DEG  C. These intermediate substituted 2,3-dimethyl compounds may themselves be prepared generally by a Diels-Alder condensation between a compound of the formula (3): <FORM:0796133/IV (b)/3> in which X and Y are as defined as above, and maleic anhydride, maleic esters, maleic acid or fumaric acid.  The resultant bicyclic compound contains a 5,6-olefinic bond which may be reduced to give the fully saturated compound if desired.  The acid, anhydride or ester formation is converted into a 2,3-dimethylol formation either by reduction of the acid or anhydride with LiAlH4 or converting into an ester which may be reduced by the action of hydrogen and a copper chromite catalyst or by sodium and alcohol. The 2,3-dimethylol groups can be converted into the corresponding halogen or acyloxy derivative by normal halogenation, e.g. with a phosphorus halide, or acylation, e.g. with an acid anhydride. Another less general method of forming the intermediate substituted dimethyl compounds is by a Diels-Alder condensation between cyclopentadiene or 1-methyl cyclopentadiene and a butene-2 derivative which may be HOCH2CH = CHCH2OH; ClCH2CH = CH-CH2Cl or RCOOCH2CH = CHCH2COOR, the product being a 2,3-dimethyl-bicyclo-[2,2,1]-hept-5-ene, in which the methyl groups carry hydroxy, chloro or acyloxy groups and in which there may be a 1-methyl substituent.  Particularly suitable starting compounds for the Dials-Alder condensation are cyclopentadiene; cyclohexadiene-1,3; furan; 2-methyl furan and 1,2-pyrone, or any compound which yields such materials under the reaction conditions, e.g. dicyclopentadiene may be substituted for the monomeric material.  The compounds containing no 5,6-double bond may be prepared by reduction of the corresponding unsaturated compound at any stage prior to the formation of the methylene groups.  In examples: (1) 1,3-cyclohexadiene was condensed with maleic anhydride, hydrogenated to give the saturated compound and reduced to the 2,3-dimethyl derivative with LiAlH4.  This was acetylated and pyrolysed to yield 2,3 - dimethylenebicyclo - [2 : 2 : 2] - octane (b.p. 89 DEG  C. at 58 mm.); (2) using the general method of Example (1) 7-oxabicyclo-[2 : 2 : 1]-heptane was prepared from furan; (3) 1 : 4-dichlorobutene-2 was condensed with cyclopentadiene (introduced as the dimer) and the resultant 2,3 - di - (chloromethyl) - bicyclo - [2 : 2 : 1]-heptane-5 was dehydrochlorinated by refluxing with alcoholic caustic potash to give 2,3 - dimethylanebicyclo - [2 : 2 : 1] - heptane - 5.ALSO:Compounds represented by formul  (1) and (2): <FORM:0796133/IV (a)/1> in which X is -H or -CH3 and in formula (1) Y is -CH2-CH2-, -O-, or -COO-; and in formula (2) is -CH2-, -CH2-CH2- or -O-(see Group IV (b)) may be polymerized in the presence of free radical-yielding catalysts.  They may also be copolymerized with 1,3-butadiene, isoprene, styrene, a -methyl styrene and chlorostyrene.  They may be polymerized at 40-60 DEG  C. in aqueous emulsion in the presence of potassium persulphate or in bulk at 90-110 DEG  C. in the presence of benzoyl peroxide.  They may also be polymerized suspended in water using a monomer-soluble catalyst to obtain granules of polymeric material.  In examples: (1) 2,3-dimethylenebicyclo[2 : 2]octane was polymerized in aqueous emulsion at 50 DEG  C. using sodium oleate as emulsifying agent with potassium persulphate and n-dodecyl mercaptan as catalyst system; (2) and (3) 2,3-dimethylene-7-oxabicyclo-[2 : 2 : 1]-heptane and 2,3-dimethylenebicyclo-[2 : 2 : 1]-heptane-5 were similarly polymerized.