Mercury divinyl

The mechanism proposed for the pyrolysis of divinyl mercury in a toluene carrier system93 is 

The photolysis of divinyl mercury at 50 °C using light of 2200-2600 A occurs by a chain mechanism94 

The rate of production of C2H2, C2H4 and C4H6 falls off as the reaction proceeds, indicating these products are consumed by secondary reactions. Addition of 400 torr of isobutane completely suppresses the formation of C4H6 and leads to a 

Addition of 400 torr of C02 decreased the overall rate of photolysis by only 25 % indicating that the vinyl radicals taking part in reaction (8) in the absence of added gas are largely thermal radicals. This is consistent with the proposed mechanism which indicates that most of the vinyl radicals are generated by reaction (8b) rather than reaction (7). 

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Ethylenemercury compounds (s. a. Divinyl-mercury) 17, 708 —, reactions with — 16, 287 Ethylenenitriles... 

This synthesis gives high yields of the desired vinyl esters but is rather cumbersome due to the necessity of preparing the starting divinyl mercury compound. 

In view of the surprising results obtained for the monofunctional maleimide HM/IPDBDVE system in Figure 3 for polymerization in air, an equimolar mixture of CHVE and MPBM [bismaleimide made from maleic anhydride and 2-methyl-l,5-pentanediamine] was polymerized via a mercury lamp source in the absence and presence of air (Figure 7). As might be expected from the earlier results in Figure 3, the difunctional maleimide/divinyl ether system exhibits a remarkably high polymerization rate in the presence of oxygen (air). 

Divinyl sulphide is also formed by the abstraction of two molecules of water from one of thiodiglycol. On treatment with gaseous hydrochloric acid, it forms aa dichloroethyl sulphide, a colourless liquid with a penetrating odour, which boils at 58 5° C. at 15 mm. mercury and has a density of 1-1972 at 15° C. On treatment of divinyl sulphide in aqueous solution with hydriodic acid, 8/3 diiodoethyl sulphide is formed (see p. 244). With chlorine various chlorinated compounds are formed, for instance, a/3 dichloroethyl vinyl sulphide ... 

SCHEME 7.97 Divinyl zinc additions and mercury cyclizations. 

Hg(CHjPh)Cl does not appear to react with phosgene at temperatures below which it decomposes to give PhCHjCHjPh [1020]. In contrast, treatment of Hg CH2C(0)H j with phosgene in thf yielded divinyl carbonate, CH j=C(H)0 2C=0 [1461a]. Similarly, treatment of either Hg CH jC(0)R Cl (R = H or Me) or Hg CHjC(0)R j with phosgene in a polar solvent (e.g. nitrobenzene, CHjClj or MeCN) at 20-60 C affords CHj=C(R)0C(0)Cl (i.e. vinyl or isopropenyl chloroformates for a review of their properties, see [61]) in excellent yields [1622]. The work was extended to include R = Ph, CMej or C3H3, and the synthesis of 1-cyclohexenyl chloroformate from mercury biscyclohexanone [1558]. 

Lithium tetravinylalanate may be prepared by a special method involving the reaction of lithium alanate with mercury divinyl (17). 

Cationic polymerization of diethyleneglycol divinyl ether and butanediol divinyl ether in the presence of oniiim salts was induced by y-irradiation. The mechanism for the initiation process involves the reduction of onium salts either by organic free radicals or solvated electrons depending on the reduction potentials of the onium salts. The reduction potentials of sulfonium salts was determined by polarography at the dropping mercury electrode. Only solvated electrons were capable of reducing the salts with reduction potentials lower than approximately -100 kJ/mol. The redox process liberates the non-nucleophilic anion from the reduced onium salt and leads to the formation of a Bronsted acid or a stabilized carbenium ion. These species are the true initiators of cationic polymerization in this system. The y-induced decomposition of onium salts in 2-ethoxyethyl ether was also followed by measuring the formation of protons. An ESR study of the structure of the radicals formed in the y-radiolysis of butanediol divinyl ether showed that only a-ether radicals were formed. 

Solid photopolymer plates for printing were pioneered by Dupont with the introduction of Dycril in 1957. The photosensitive layer in Dycril is a 0.3-1.0mm thick binder composed of a water-soluble cellulose derivative such as cellulose acetate succinate, a monomer of the divinyl type such as triethylene glycol diacrylate, and a photo-initiator such as 2-ethylanthraquinone and a thermal stabilizer (inhibitor) of the p-methoxyphenol type. The mixture is applied on an aluminum support or steel with an adhesive sheet and exposure to actinic radiation from a carbon or mercury arc lamp is performed through a negative placed over the photosensitive layer. Postexposure treatment involves washing with a 0.2-0.5% caustic soda solution that removes the unexposed area and leaves a relief on the support. Dycril is fairly cheap, has a fairly high resolving power, and is durable. 

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