Patent GB-788662-A (GB)
Title: Improvements in or relating to polymerizable cyclic compounds
IPC: C08G61/00
Filed: 1954-09-29
Abstract: The invention comprises a polymerizable cyclic compound in a condensed phase having a quinoidal or diradical structure and which may be identified by being readily reactable with iodine below minus 45 DEG  C. to produce 1 : 4-diiodomethyl benzene; 1 : 4-diiodomethyl naphthalene; a heterocyclic 1 : 4-diiodomethyl compound having one or two six-membered rings and containing at least one hetero nitrogen atom vicinal only to carbon atoms, or a nuclear substitution product of the foregoing compounds with fluorine and/or chlorine atoms and with methyl groups.  The term "quinoidal structure" refers to a dimethylene cyclohexadiene and its naphthalene and heterocyclic analogues.  The compound can also exist in its alternative resonance form, i.e. as the aromatic diradical structure.  The term "condensed phase" covers both the solid and liquid state of the product.  The invention also comprises a method of preparing in stable form and in a condensed phase, a cyclic compound capable of polymerization, which comprises pyrolysing (1) p-xylene, (2) 1 :4-dimethylnaphthalene, (3) a heterocyclic 1 :4-dimethyl compound having one or two six-membered rings and containing at least one nitrogen atom vicinal only to carbon atoms, or a nuclear substitution product of the foregoing compounds with fluorine and/or chlorine atoms and with additional methyl groups, at a temperature between about 700 DEG  and 1300 DEG C. and at a total pressure not higher than about 400 mm. Hg. for a period of not more than one second and quenching the pyrolyzed vapours in a cold liquid at a temperature not higher than about minus 45 DEG  C.  The pyrolysis is preferably effected at 950 DEG  to 1300 DEG  C. for a time between 0.1 and 0.001 second.  It may be effected in the presence of an inert gas such as carbon dioxide, steam or nitrogen, particularly when the partial pressure of the compound is 10 mm. or less.  Liquids for quenching include various paraffinic, cycloparaffinic and aromatic hydrocarbons, halogenated hydrocarbons carbonyl compounds, alcohols, and other liquids such as carbon disulphide.  Starting materials specified are para-xylene, pseudocumene, durene, isodurene, prehnitene, pentamethylbenzene, hexamethylbenzene, 1 : 4-dimethyl naphthalene and 1,2,3,4,6,7 - hexamethylnaphthalene; 2 : 5 - dimethylpyrazine, 2 : 5-lutidine, 2 : 5-dimethylpyrimidine, 5,8-dimethyl quinoline, 1,4-dimethyl isoquinoline, 5,8-dimethyl quinazoline, 5,8 - dimethyl quinoxaline, 2,3,5 - trimethyl pyrazine, 2,3,5,6-tetramethyl pyrazine, 2,3,5-or 2,4,5-trimethyl pyradine, 5,6,8-trimethyl quinoline; 2-chloro-p-xylene, 2-fluoro-p-xylene, 2,5 - dichloro - p - xylene, 2,5 - difluoro - p - xylene, 2,3,5 - trichloro - p - xylene, 2,3,5 - trifluoro - p - xylene, 2,3,5,6 - tetrachloro - p - xylene, 2,3,5,6 - tetrafluoro - p - xylene, 2 chloro - 3,5,6 - trimethyl - benzene, 6 - chloro - 1,4 - dimethyl naphthalene, 2,3,6,7 - tetrachloro - 1,4 - dimethyl naphthalene and 2,5-dimethyl-6-chloro-pyrazine.  A mixture of terpenes acts as a polymerization inhibitor for the products.  In Example (1) p-xylene vapour at 5 mm. pressure and 700 DEG  C. is passed through a pyrolysis tube heated at 1000 DEG  C., the vapours being passed into a chloroform-carbon tetrachloride mixture cooled to minus 80 DEG  C. Solid p-xylene and solid monomer precipitate and are filtered off. The mother liquor and the precipitate both react with iodine to give 1,4-diiodomethyl benzene.  The monomer, in chloroform-carbon tetrachloride solution, if warmed to room temperature, gives an insoluble polymer.  Other examples describe the pyrolysis under somewhat similar conditions of (2) 2-fluoro-p-xylene; (3) 1,4-dimethyl naphthalene; (4) pseudocumene, the monomer being collected and allowed to polymerize, and in Examples (2) and (3) being reacted with iodine to give 2-fluoro-1,4-di-iodomethyl benzene and 1,4-di-iodomethyl naphthalene respectively.  Specifications 650,947, 673,651 and 718,106, [Group IV (a)], are referred to.ALSO:Polymers are obtained by polymerization of a polymerizable cyclic compound in a condensed phase having a quinoidal or diradical structure and which may be identified by being readily reactable with iodine below minus 45 DEG  C. to produce 1:4-di-iodomethyl benzene; 1:4-di-iodomethyl naphthalene; a heterocyclic 1:4-di-iodomethyl compound having one or two six-membered rings and containing at least one hetero nitrogen atom vicinal only to carbon atoms, or a nuclear substitution product of the foregoing compounds with fluorine and/or chlorine atoms and with methyl groups.  The term "quinodial structure" refers to a dimethylene cyclohexadiene and its naphthalene and heterocyclic analogues.  Such polymerizable compounds are obtained by pyrolysing (1) p-xylene, (2) 1:4-dimethylnaphthalene, (3) a heterocyclic 1:4-dimethyl compound having one or two six-membered rings and containing at least one nitrogen atom vicinal only to carbon atoms or a nuclear substitution product of the foregoing compounds with fluorine and/or chlorine atoms and with additional methyl groups, at a temperature in the range of about 700 DEG  to 1300 DEG  C. and at a total pressure not higher than about 400 mm. mercury for a period of not more than one second and quenching the pyrolysed vapours in a cold liquid at a temperature not higher than about minus 45 DEG  C.  Starting materials specified are p-xylene, pseudocumene, durene, isodurene, prehnitene, pentamethylbenzene, hexamethylbenzene, 1,4 - dimethylnaphthalene and 1,2,3,4,6,7 - hexamethylnaphthalene; 2,5 - dimethylpyrazine, 2,5-butidine, 2,5-dimethylpyrimidine, 5,8-dimethylquinoline, 1,4-dimethylisoquinoline, 5,8-dimethylquinazoline, 5,8-dimethylquinoxaline, 2,3,5 - trimethylpyrazine, 2,3,5,6 - tetramethylpyrazine, 2,3,5- or 2,4,5-trimethylpyradine, 5,6,8 - trimethylquinoline; 2 - chloro - p - xylene, 2 - fluoro - p - xylene, 2,5 - dichloro - p - xylene, 2,5 - difluoro - p-xylene, 2,3,5 - trichloro - p - xylene, 2,3,5-trifluoro - p - xylene, 2,3,5,6 - tetrachloro - p-xylene, 2,3,5,6 - tetrafluoro - p - xylene, 2-chloro - 3,5,6 - trimethylbenzene, 6 - chloro-1,4 - dimethyl - naphthalene, 2,3,6,7 - tetrachloro - 1,4 - dimethyl - naphthalene and 2,5-dimethyl - 6 - chloro - pyrazine. Copolymers of the condensed monomers may also be prepared. Examples describe the preparation of polymers by heating to room temperature monomeric pyrolysis products of (1) p-xylene; (2) 2-fluoro-p-xylene; (3) 1:4-dimethyl naphthalene; (4) pseudocumene. Specifications 650,947, 673,651 and 718,106 are referred to.