Investigations on the mechanism of flame retardancy in HET acid containing unsaturated polyester resins - discussion of mass spectra of the flame retardants

Abstract

The mass spectra of hexachlorocyclopentadiene (HEX), HET acid (1,4,5,6,7,7-hexachloro-6-norbornene-2,3-dicarboxylic acid), its corresponding anhydride and HET acid diethylester, model compound for HET acid containing polyesters were recorded using an electron impact ion source. HET acid diethylester undergoes mainly the retro Diels-Alder process whereas HET anhydride looses CO 2, CO and C1 · resulting in a C 7H 2Cl 5 + ion. The structure of this particular ion is discussed to some extent because one possible molecular architecture is a bridged form, which in solution chemistry is argued to be a non-classical carbonium ion.