Chloro hydrin

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... 

A synthetically useful diastereoselectivity (90% dc) was observed with the addition of methyl-magnesium bromide to a-epoxy aldehyde 25 in the presence of titanium(IV) chloride60. After treatment of the crude product with sodium hydride, the yy -epoxy alcohol 26 was obtained in 40% yield. The yyn-product corresponds to a chelation-controlled attack of 25 by the nucleophile. Isolation of compound 28, however, reveals that the addition reaction proceeds via a regioselective ring-opening of the epoxide, which affords the titanium-complexed chloro-hydrin 27. Chelation-controlled attack of 27 by the nucleophile leads to the -syn-diastereomer 28, which is converted to the epoxy alcohol 26 by treatment with sodium hydride. 

The combination of BSTP 1949 with SnCl4 converts olefins such as cyclopen-tene 1991a, cyclohexene 1991b, or cycloheptene 1991c into their trans-l,2-chloro-hydrins 1992 a-c in 74, 85 and 92% yield, respectively [168]. Reaction of the cyclic... 

A novel chiral phosphonic amide-SiCl4 complex has also been found to serve as a catalyst for additions of allenyltributyltin to aldehydes (Table 9.45) [78], The reaction is limited to aromatic aldehydes because of competing formation of silylated chloro-hydrins from aliphatic aldehydes and the SiCI4 reagent. 

Carra S., Morbidelli, M., Santacesaria, E. and Buzzi, G., 1979, Synthesis of propylene oxide from propylene chloro-hydrins — II. Chem. Engng Sci. 34, 1133-1140. 

Benson LO, Teta MJ Mortality due to pancreatic and lymphopoietic cancers in chloro-hydrin production workers. BrJ Ind Med 50 710-716, 1993... 

Epichloro- hydrin Epichloro- hydrin Polychrloro- methyl oxirane CO Poly(cpi- chloro hydrin) Poly[oxy- (chloro- methyl) ethylene] CH 136 40-90 18 350 251... 

The Carbide and Carbon Co began large scale manuf of EtnO thru ethylene chloro-hydrin in 1925 and by the direct oxidation of ethylene in 1937. Dow entered the field in 1939 Si 1941 Jefferson and Wyandotte in 1941 and Mathieson Chem Corp in 1951. These four Co s used the chlorohydrin method. US consumption, which was in 1939 108 million pounds, increased in 1949 to 354 million Several laboratory methods of prepn are described in Ref 17, pp 75—7. In one of them hydroxide is added gradually to a soln of 2-chloroethyI acetate heated to a temp betwn 40 150°C. An excess of unreacted base is avoided. The reaction proceeds as follows ... 

Triphenylphosphine was purchased from Aldrich Chemical Company, Inc. Use of a considerable excess of triphenylphosphine ensures complete reaction and obviates the need for rigorously dried glassware and reagents. Hydrochloric acid, generated by the reaction of dichlorotriphenylphosphorane and water, can react with the epoxide to produce a trans -chlorohydrin rrans-chloro-hydrins, however, are converted to cis-dichlorides by dichloro-tripbenylphnsphnrane under the conditions of the reaction. 

According to descriptions published by the Thiokol Chemical Corporation [9] and Gobel [10] liquid thiokol is obtained in the following way ethylene chloro-hydrin is condensed into dichlorodiethylformal (I) which is then treated with sodium polysulphide to form the polymer (II) ... 

Commerciol Dichlorohydrin consists of the above two isomers, the proportions of which depend on method of prepn d 1.36-1.39, bp 175-80°, flash p 74°, Glycerol was the main source for the prepn of glycerol chloro-hydrins until the process for direct substitutive chlorination of propylene to allyl chloride paved the way for synthesis by chlorohydrination of allyl chloride. In the synthesis from glycerol, excess HCI is used in the presence of 4% acetic acid. The reaction is run at 130° to yield 90% of product which is mainly the a,y-form. Synthesis from propylene yields a mixt of approx 70% a,/8-form 8c 30% a,y-form. Addn of HCI to epichlorohydrin, CH2 CHCH> Cl, at... 

But addition of p-methoxy- or p-ethoxyphenylmagnesium bromide to a-chloroaoetone [Pg.377]

Explain which of the following epoxide products is formed when the chloro-hydrin reactant is treated with base. 

Current commercial production of methyloxirane (propene oxide), used extensively in the production of polyurethanes, is usually based on a chloro-hydrin process. However, the direct gas-phase synthesis of methyloxirane... 

Propylene Oxide. Propylene oxide is another basic chemical used in manufacturing intermediates for urethane foams (cushioning and insulation), coatings, brake fluids, hydraulic fluids, quenchants, and many other end uses.23 The classic industrial synthesis of this chemical has been the reaction of chlorine with propylene to produce the chloro-hydrin followed by dehydrochlorination with caustic to produce the alkylene oxide, propylene oxide, plus salt. 

Not more than 3 mg/kg of residual propylene chloro-hydrin... 

A cheaper and more convenient alternative to iodine is N-chlorosuccinimide, which cleaves 5,5-acetals in aqueous acetonitrile containing a mild base such as 2,6-lutidine. In the example shown in Scheme 2.69, note the absence of chloro-hydrin formation from the terminal alkene under the reaction conditions.150 N-Bromosuccinimide performs the same task under similar conditions but alkenes are incompatible.152 153... 

Figure 9. XPS valence band spectra of (A) polyvinyl chloride, (B) polyfepi chloro-hydrine), (C) poly(chlorotrifiuoroethylene), (D) cofethylene-tetrafluoroethylene...

Chlorohydrins from epoxides. Steroid epoxides are converted into chloro-hydrins by this reagent (benzene, 20°). The ring opening is of the usual trans, diaxial type conditions are so mild that side reactions observed with hydrochloric acid are avoided. ... 

Esters of halohydrins. Treatment of 2-carboxy-1,3-dioxolanes (1) with phosphorus pentachloride in methylene chloride at room temperature gives esters of 1,2-chloro-hydrins (2) in about 80% yield. Similarly treatment of the 2-carboxy-l,3-dioxane (3) yields an ester of a 1.3-chlorohydrin (4). Reaction of (5 2-carboxy-2-methyl-l,3-... 

Anhydrous RuCb catalyzes the reaction of epoxides with acetone (in acetone under reflux, 1.5-5 h) to give 1,3-dioxolanes [64]. The same catalyst, in the presence of ammonium thiocyanate, converts epoxides into thiiranes. The reaction takes place with inversion of configuration (R)-(-r)-styrene oxide was converted into (5)-(-)-sty-rene sulfide of 78 % optical purity [65]. This transformation is also mediated by catalytic amounts (2 %) of an Fe(III) pentafluorophenylporphyrin complex [66]. Chloro-hydrins are formed on treatment of epoxides with stoichiometric amounts of FeCl3 in ether [67]. 

A total synthesis of precalciferol (377) has been reported, which involved nucleophilic addition of the lithium salt (374) to the ketone (373), giving the acetylenic tricyclic intermediate (375). Elimination of HOCl from the chloro-hydrin (375) with bis(ethylenediamine)chromium(n) afforded the en-yn-ene (376), which was reduced to precalciferol (377) with Lindlar s catalyst. Thermal isomerization of (377) then afforded vitamin D3 (378). ... 

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