Hydrines

Epichlorohydnn is the common name of an industrial chemical used as a component in epoxy cement The molecular formula of epichlorohydnn is C3H5CIO Epichlorohydnn has an epoxide functional group it does not have a methyl group Write a structural formula for epichloro hydrin... 

The formation of vicinal halohydrms from alkenes was described m Section 6 17 Halo hydrins are readily converted to epoxides on treatment with base... 

Cham extension by way of cyano hydrin formation (Section 25 20)... 

Polymers. Studies to determine possible exposure of workers to residual epichl orohydrin and ethylene oxide monomers in the polymers have been done. Tests of warehouse air where Hydrin H and Hydrin C are stored showed epichl orohydrin levels below 0.5 ppm. Air samples taken above laboratory mixing equipment (Banbury mixer and 6" x 12" mill) when compounds of Hydrin H or C were mixed gave epichl orohydrin levels below detectable limits, and ethylene oxide levels less than 0.2 ppm, well below permissible exposure limits (46). A subacute vapor inhalation toxicity study in which animals were exposed to emission products from compounded Parel 58 suggests that no significant health effects would be expected in workers periodically exposed to these vapors (47). 

Form Number 4, Material Safety Data Sheet, Hydrin Elastomers, MSDS Number Z0812.89, Zeon Chemicals USA, Inc., LouisviUe, Ky., 1989. 

S-methyl dithiocarbonate (76S413). Stereoselective isomerization of 1,2-disubstituted alkenes may be achieved by a sequence such as the following fr<2n5-alkene bromo-hydrin -> /3-hydroxythiocyanate -> cw-thiirane -> cw-alkene (75TL2709). 

This approach was used in the development of the epichlorhydrin rubbers which became commercially available around 1965 from Goodrich (Hydrin) and Hercules (Herclor). Both homopolymers of epichlorhydrin (Hydrin 100, Herclor H) and copolymers of epichlorhydrin with ethylene oxide (Hydrin 200, Herclor C) became available. (In 1986 Hercules sold their interest in these materials to Goodrich, who in turn later sold this to Nippon Zeon). 

If polypropylene is too hard for the purpose envisaged, then the user should consider, progressively, polyethylene, ethylene-vinyl acetate and plasticised PVC. If more rubberiness is required, then a vulcanising rubber such as natural rubber or SBR or a thermoplastic polyolefin elastomer may be considered. If the material requires to be rubbery and oil and/or heat resistant, vulcanising rubbers such as the polychloroprenes, nitrile rubbers, acrylic rubbers or hydrin rubbers or a thermoplastic elastomer such as a thermoplastic polyester elastomer, thermoplastic polyurethane elastomer or thermoplastic polyamide elastomer may be considered. Where it is important that the elastomer remain rubbery at very low temperatures, then NR, SBR, BR or TPO rubbers may be considered where oil resistance is not a consideration. If, however, oil resistance is important, a polypropylene oxide or hydrin rubber may be preferred. Where a wide temperature service range is paramount, a silicone rubber may be indicated. The selection of rubbery materials has been dealt with by the author elsewhere. ... 

It will be seen from the foregoing that there is no systematic nomenclature for these compounds. Some of them have been isolated by several workers and with the impression that they were new substances have been given new names, and this applies especially to the two isocinchonines and dihydrocinchonine. It will be noticed that instead of the two geometrical isomerides required by formula (Ga) there are three cinchon-hydrines. The a- and jS-forms are well-defined crystalline substances, but the supposed y-form (see table, p. 452) is amorphous and its authenticity doubtful. Eormula (E) requires two geometrical isomerides, but quinidine... 

A large variety of methods is applicable to the formation of isolated double bonds. This permits selection of reagents compatible with other functionality present. Alcohol dehydration, ester elimination and other nonreductive p eliminations are the most common methods. Reductive elimination of halo-hydrins, vic-dihalides, etc., and of a variety of ketone derivatives has also been used. 

A variety of conditions has been used to prepare oxiranes from trans-hxomo-hydrins. In general, bromohydrins are heated in a solution of 5-10% methanolic potassium hydroxide for 30 min to 8 hr. Longer reflux times are required for bromohydrins which are not anti-coplanar, e.g., diequatorial bromohydrins. A 5 % solution of potassium acetate in boiling ethanol can be used to cyclize steroidal bromohydrins containing base sensitive groups. The use of 1.1 equivalents of sodium methoxide per equivalent of steroid in methanol solution is especially recommended for 9a-bromo-l lj5-hydroxy steroids. 

The primary product of hypohalite photolysis is a 1,5-halohydrin, the stability of which increases on passing from iodo- to bromo- to chloro-hydrins. If spontaneous elimination of hydrogen halide does not occur, the halohydrins can be converted into tetrahydrofurans by base treatment. In several instances it has been possible to isolate the intermediate... 

Superose gel material of Pharmacia Biotech is a highly epichloro-hydrine cross-linked agarose matrix that has a pH range of 3-12 (short term 1-14). Hydrophilic interactions may be noticeable for lipids, peptides, and small aromatic compounds, but such interactions might even improve resolution. Superose medium is available in two different porosities Superose 6 HR 10/ 30 (bead size 13 2 /um maximum pressure 1.5 MPa) and Superose 12 HR 10/30 (bead size 10 2 /um maximum pressure 3.0 MPa). 

TABLE 16.5 Producers (Pharmacia Biotech) Specification of Fractionation Ranges of Epichloro-Hydrine Cross-Linked Agarose-Based Superose Geis... 

Prepacked columns with cross-linked high-resolution (HR) agarose gels provide a high number of theoretical plates and fast separations (29,30).The Superose gel material of Pharmacia Biotech is a highly epichloro-hydrine cross-linked... 

Alkylation of the dihydroxyacetophenone, 44, with epichloro-hydrin results in condensation of two molecules of the phenol with the latent glycerol (45). Reaction of the intermediate with ethyl oxalate affords the chromone ester, 46. Saponification leads to the bronchiodilator cromoglycic acid (47). The agent is usually administered by oral insufflation as its extremely insoluble disodium salt. 

Brom-benzol, n. bromobenzene. calcium, n. calcium bromide, -cyan, n. cyanogen bromide, bromocyanogen. -dampf, tn. bromine vapor, -eisen, n. iron bromide, -fiasche, /. bromine bottle, -fluor, n. bromine fluoride, -gehalt, tn. bromine content, -gold, n. gold bromide, -goldkalium, n. potassium auri-bromide, potassium bromoaurate. bromhaltig, a. contaim ng bromine, Brom-hydrat, n. hydrobromide bromine hydrate. -hydrin, n. bromohydrin. 

Chin-hydrin, n. quinhydrine. -hydron, n. quinhydrone. -icin, n. quinicine. 

Chlor-hydrat, n. hydrochloride chlorine hydrate. -hydrin, n. chlorohydrin. 

The 1 f)-carbamovlmethvlphenoxv-2,3-epoxypropane used as starting material may be obtained as follows a mixture of 3.2 grams of p-hydroxyphenylacetamide, 25 ml of epichloro-hydrin and 6 drops of piperidine is heated at 95°-100°C for 6 hours. The mixture is cooled and filtered and the solid product is crystallized from methanol. There is thus obtained 1 -p-carbamovlmethvlphenoxy-2,3-epoxvpropane, MP 158°-160°C. 

Another method for the synthesis of epoxides is through the use of halo-hydrins, prepared by electrophilic addition of HO-X to alkenes (Section 7.3). When a halohydrin is treated with base, HX is eliminated and an epoxide is produced. 

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