Halomethylation of polymer
AssigneeBayer Rubber Inc.
InventorAkhtar Osman
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Abstract
A process is provided for the halomethylation of the aromatic groups in an isoolefin-vinylidene aromatic monomer polymer by the in situ generation of the halomethylating species formed by the reaction of a methoxy alkoxy methane with a thionyl halide, the halomethylation of the polymer being catalyzed by a Lewis acid.
Claims12
A process for the preparation of a halogen-containing polymer without the substantial formation of gel by reacting a polymer containing a C.sub.4 to C.sub.7 isomonoolefin and a vinylidene substituted aromatic monomer selected from styrene and alpha-methylstyrene with a halomethylating agent generated in situ which comprise the step of:
- (i) providing in a suitable reaction vessel (a) a solution in an organic solvent of the polymer wherein said polymer contains from about 80 to about 98 weight percent of the C.sub.4 to C.sub.7 isomonoolefin and from about 20 to about 2 weight percent of the vinylidene substituted aromatic monomer for a total of 100 weight percent and (b) from about 1.times.10.sup.-2 to about 2.times.10.sup.-2 mols per gram of polymer of a methoxy alkoxy methane of the general formula ROCH.sub.2 OCH.sub.3 wherein R is an alkyl group having from 1 to 8 carbon atoms and cooling said solution to about 0.degree. to 20.degree. C.,
- (ii) adding to the solution of step (i) from about 2.times.10.sup.-3 to about 2.times.10.sup.-2 mols per gram of polymer of a thionyl halide,
- (iii) cooling said solution of step (ii) to about 0.degree. to about 20.degree. C. and adding from about 5.times.10.sup.-4 to about 5.times.10.sup.-3 mols per gram of polymer of Lewis acid optionally dissolved in an organic solvent,
- (iv) heating the solution from step (iii) to a temperature of from about 45.degree. C. to about 80.degree. C. for a period of from about 3 hours to about 10 hours whereby a portion of the aromatic rings in the vinylidene substituted aromatic monomer in the polymer are halomethylated, and,
- (v) recovering the halogen-containing polymer.
A process for the preparation of a chlorine-containing polymer without the substantial formation of gel by reacting a polymer containing isobutylene and styrene with a chloromethylating agent generated in situ which comprises the steps of:
- (i) providing in a suitable reaction vessel (a) a solution of the polymer in an organic solvent selected from chloroform, chlorobenzene, C.sub.4 to C.sub.6 cyclic ethers and mixtures thereof wherein said polymer contains from about 80 to about 98 weight percent of isobutylene and from about 20 to about 2 weight percent of styrene monomer based on the total of the isobutylene and styrene in the polymer and (b) from about 1.times.10.sup.-2 to about 2.times.10.sup.-2 mols per gram of polymer of dimethoxymethane, and cooling said solution to about 0.degree. to about 20.degree. C.,
- (ii) adding to the solution of step (i) from about 2.times.10.sup.-3 to about 2.times.10.sup.-2 mols per gram of polymer of thionyl chloride and allowing the mixture to age for about 15 minutes to about 3 hours,
- (iii) cooling said solution of step (ii) to about 0.degree. to about 20.degree. and adding about 5.times.10.sup.-4 to about 5.times.10.sup.-3 mols of tin tetrachloride per gram of polymer optionally dissolved in an organic solvent,
- (iv) heating the solution from step (iii) to a temperature of from about 45.degree. C. to about 80.degree. C.
- for a period of from about 3 hours to about 10 hours whereby a portion of the aromatic rings in the styrene monomer are chloromethylated, and
- (v) recovering the chlorine-containing polymer.
Dependencies are inferred from the claim text.