We also showed that dehydrohalogenation
of different halogen-containing structures in the third comonomer of halo-EPDM during the process of vulcanization, in the presence of dehydrohalogenated agents that are always present in rubber compositions (for example, ZnO), brings to formation new additional double bonds in situ, which causes additional rise in the rate of vulcanization of chlorinated EPDM (CIEP-DM) (refs.
halobutyls, there is no concern for dehydrohalogenation
at or above 160 degrees C.
The epoxidation reaction of a polyol with epichlorohydrin is very well known (1, 2), and it occurs in two steps; 1, Formation of an intermediate chlorohydrin and 2 dehydrohalogenation
to form the glycidyl ether
1)H-NMR spectrum integration pro vided conjugated diene and residual allylic bromide contents, using chemical shift assignments developed during previous studies of BUR dehydrohalogenation
The second reaction is used to perform a dehydrohalogenation
using potassium hydroxide as base (KOH), affording exo-DCPD as depicted in Fig.
The higher state of cure and better aging presumably result from the minimization of the dehydrohalogenation
side reaction that occurs with conventional accelerators for the zinc oxide cure system.
In the case of the halogenated phenolic resins, a dehydrohalogenation
reaction (figure 9) will provide the suitable conjugated diene structure.
Chlorine content determined by dehydrohalogenation
Crosslinking efficiency of polymer radicals in halogenated elastomers is typically reduced through dehydrohalogenation
2] and D diethylamine pentachlorophenol photochemical degradation W/C DDT dehydrohalogenation
R reductive dehalogenation R 2,4-D microbial metabolism, D/W hydroxylation malathion oxidation, hydrolysis D carbaryl hydrolysis, hydroxylation D trifluralin oxidative N-dealkylation, D/R reduction methoprene oxidation, metabolic D processes abamectin hydrolysis, oxidation R/D (a) R = residue remains for years; D = degrades to innocuous products within days to weeks; W = residues remain in contaminated water for years; C = persistent contaminants (dioxins).
The synthesis of spirobifluorenyl-substituted PPV  by the dehydrohalogenation
of 1,4-bis(bromomethyl)-2-(2'-ethylhexyloxy)-5-(2"-((2"',7"'-di-tert-butyl)-9",9"'-spirobifluorenyl)) benzene using large excess of potassium tert-butoxide is one example of the Gilch procedure.
When zinc oxide is used to crosslink halobutyl rubber, carbon-carbon bonds are formed through dehydrohalogenation
which result in a compound with a very stable crosslink system, good retention of aged properties and a low compression set.