ISSN:
0449-296X
Schlagwort(e):
Physics
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Poly-p-xylylenes were prepared by electrolytic reduction of α,α′-dihalo-p-xylenes at controlled cathode potentials (c.p.). Polymers and halides are formed at the cathode; at the anode the halide is oxidized to halogen. Poly-p-xylylene was prepared from α,α′-dichloro-p-xylene (c.p. -1.2 v.) and α,α′-dibromo-p-xylene (c.p. -1.2 v.); poly-p-2-chloroxylylene from α,α′,2-trichloro-p-xylene (c.p. -1.4 v.) and α,α′-dibromo-2-chloro-p-xylene (c.p. -1.2 v.); poly-α,α,α′,α′-tetrachloro-p-xylylene from α,α,α,α′,α′,α′-hexachloro-p-xylene (c.p. -0.7 v.), and poly-α,α,α′,α′-tetrafluoro-p-xylylene from α,α′-dibromo-α,α,α′,α′-tetrafluoro-p-xylene (c.p. -1.1 v.). The cathode potentials were measured and controlled with respect to a saturated calomel electrode. Current efficiencies up to 96% were observed. α,α,α′,α′-Tetrachloro-p-xylylene was identified as an intermediate in the reduction of α,α,α,α′,α′,α′-hexachloro-p-xylene. A general mechanism for these reactions is suggested and discussed. It involves elimination of halide by a two-electron charge transfer with formation of a xylyl anion, followed by an elimination of halide in α′-position yielding xylylenes which then polymerize.
Zusätzliches Material:
1 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1966.150040603
Permalink
