Synthesis of alkylthio-substituted poly (p-phenylene-vinylene) polymers

摘要

The invention relates to a process for the preparation of 2,5-di (alkylthio) -α, α'-dihalo-p-xylenes of the following formula (3), wherein R and R 'are each independently selected from saturated, linear, branched or cyclic C1 -C20-Aikylresten is selected and X is selected from Cl and Br, comprising the reaction of 1,4-diiodobenzene (1a) to 1,4-di (alkylthio) benzenes (2) and their para-halomethylation by reaction with formaldehyde ( CH2O) in the presence of the corresponding hydrogen halide (HX) to the corresponding 2,5-di (alkylthio) -α, α'-dihalo-p-xylenes (3), where either: i) when R = R ', 1, 4-diiodobenzene (1a) directly with 2 mol of thiol of the formula R-SH to the corresponding 1,4-di (alkylthio) benzene (2) and then to the corresponding 2,5-di (alkylthio) -α, α'-dihalogeno p-xylene (3) is reacted; or ii) when R ≠ R ', 1,4-diiodobenzene (1a) is first reacted with 1 mol of alkyl iodide of formula RI to give the corresponding 4- (alkylthio) iodobenzene (1b), then with 1 mol of thiol of formula R'-SH mixed 1,4-di (alkylthio) benzene (2) and finally reacted with formaldehyde in an analogous manner as above to give the mixed 2,5-di (alkylthio) -α, α'-dihalo-p-xylene (3).