Alkyl hypochlorites

Epoxidation Catalyzed by Metalloporphyrins. Metalloporphyrins, which have thoroughly studied as catalysts in alkane oxygenations, have also been tested as epoxidation catalysts.119,122,244,245,307 Iodosylbenzene (PhIO), sodium hypochlorite, alkyl hydroperoxides, potassium hydrogen persulfate, and molecular oxygen are the oxygen sources used most frequently in these oxidations.119... 

Many unsaturated chloro- and bromo-hydrocarbons and many polychloro and polybromo compounds decompose by radical-chain mechanisms, but only the chloro compounds have been studied in reasonable detail, presumably owing to the complex nature of the chain reactions in the case of the bromo compounds. Other examples of compounds which undergo radical-chain decompositions are 2,2-dichlorodiethyl ether oxalyl chloride alkyl hypochlorites alkyl peroxychloroformates and alkyl chloro-sulphites in the gas phase ... 

Historically, the interest of using manganese complexes as catalysts for the epox-idation of alkenes comes from biologically relevant oxidative manganese porphyrins. The terminal oxidants compatible with manganese porphyrins were initially restricted to iodosylbenzene, sodium hypochlorite, alkyl peroxides and hydroperoxides, JV-oxides, KHSO5, and oxaziridines. Molecular oxygen can also be used in the... 

Secondary alcohols are oxidized at room temperature to ketones in high yields by HOCl generated in situ from aqueous NaOCl and acetic acid (109,110). Selective oxidation in the presence of a primary alcohol is possible. In methanol, aldehydes are oxidized to methyl esters (110). Under the proper conditions, alcohols can be esterified with HOCl forming isolable alkyl hypochlorites. 

Alkyl hypochlorites, esters of hypochlorous acid, are nonpolar, volatile Hquids with irritating odors and are extremely lachrimatory. The known alkyl hypochlorites (ROCl) are methyl (CH ) [593-78-2] ethyl (C2H ) [624-85-1] /-butyl (/-C H ) [307 0 ], and /-amyl [24251 -12-5], Primary and... 

Numerous fluorinated and perfluorinated alkyl hypochlorites have been synthesized and characterized, eg, CF OCl [22082-78-6] C2F OCl [22675-67-8] /-C F OCl [22675-68-9] and /-C F OCl [22082-78-6]. These nonmetal oxychlorine compounds are much more thermally stable than the corresponding parent compounds and can be prepared by reaction of GIF with the appropriate carbonyl compound or alcohol. 

Physical Properties. Data on physical properties of organic hypochlorites is limited. Some boiling points and densities of alkyl hypochlorites have been pubUshed as well as data on viscosity (259), uv spectra (8) and partition coefficients between CCl and water (260). The Hquid-phase equiUbria for... 

The kinetics of formation and hydrolysis of /-C H OCl have been investigated (262). The chemistry of alkyl hypochlorites, /-C H OCl in particular, has been extensively explored (247). /-Butyl hypochlorite reacts with a variety of olefins via a photoinduced radical chain process to give good yields of aUyflc chlorides (263). Steroid alcohols can be oxidized and chlorinated with /-C H OCl to give good yields of ketosteroids and chlorosteroids (264) (see Steroids). /-Butyl hypochlorite is a more satisfactory reagent than HOCl for /V-chlorination of amines (265). Sulfides are oxidized in excellent yields to sulfoxides without concomitant formation of sulfones (266). 2-Amino-1, 4-quinones are rapidly chlorinated at room temperature chlorination occurs specifically at the position adjacent to the amino group (267). Anhydropenicillin is converted almost quantitatively to its 6-methoxy derivative by /-C H OCl in methanol (268). Reaction of unsaturated hydroperoxides with /-C H OCl provides monocyclic and bicycHc chloroalkyl 1,2-dioxolanes. 

In contrast to the alkyl hypochlorites, the fluoroalkyl hypochlorites are extremely susceptible to hydrolysis but are much more thermally stable. Trifluoromethyl hypochlorite, eg, showed no decomposition when heated for several days at 100°C. When decomposition does occur, several products are formed C2F OCl gives COF2, CF Cl, CF COF, and GIF, whereas (GF2)3GOGl gives (GF2)2GO, GI2, GF Gl, and G2F (40). 

Ghlorohydrination with er -All l Hypohalites. Olefins react with ethyl hypochlorite [624-85-1] to form the corresponding chlorohydrin (49). In 1938 both Shell Development Co. (50) and Arthur D. Litde, Inc. (51) patented the preparation of chlorohydrins by the reactions of olefins with tertiary alkyl hypochlorites. Examples with ethylene and propylene in the Shell patent reported chlorohydrin yields of greater than 95% with tert-huty hypochlorite [507-40-4]. 

Almost 40 years later the Lummus Co. patented an integrated process involving the addition of chlorine along with the sodium chloride and sodium hydroxide from the cathode side of an electrolytic cell to a tertiary alcohol such as tertiary butanol to produce the tertiary alkyl hypochlorite. The hypochlorite phase separates, and the aqueous brine solution is returned to the electrolytic cells. The alkyl hypochlorite reacts with an olefin in the presence of water to produce a chlorohydrin and the tertiary alcohol, which is returned to the chlorinator. With propylene, a selectivity to the chlorohydrin of better than 96% is reported (52). A series of other patents covering this technology appeared during the 1980s (53—56). 

Fatty acids are prepared by acylating thiophene with acid chlorides and reducing the ketones (218) to alkylthiophenes according to Wolff-Kishner or Clemmensen. The latter are then acetylated and oxidized by hypochlorite to 5-alkyl-2-thiophenecarboxylic acids, > ... 

There are several available terminal oxidants for the transition metal-catalyzed epoxidation of olefins (Table 6.1). Typical oxidants compatible with most metal-based epoxidation systems are various alkyl hydroperoxides, hypochlorite, or iodo-sylbenzene. A problem associated with these oxidants is their low active oxygen content (Table 6.1), while there are further drawbacks with these oxidants from the point of view of the nature of the waste produced. Thus, from an environmental and economical perspective, molecular oxygen should be the preferred oxidant, because of its high active oxygen content and since no waste (or only water) is formed as a byproduct. One of the major limitations of the use of molecular oxygen as terminal oxidant for the formation of epoxides, however, is the poor product selectivity obtained in these processes [6]. Aerobic oxidations are often difficult to control and can sometimes result in combustion or in substrate overoxidation. In... 

Still another method for the conversion of halides to acid derivatives makes use of Na2Fe(CO>4. As described in 10-112, primary and secondary alkyl halides and tosylates react with this reagent to give the ion RFefCO) (142) or, if CO is present, the ion RCOFe(CO)4 (143). Treatment of 142 or 143 with oxygen or sodium hypochlorite gives, after hydrolysis, a carboxylic acid. " Alternatively, 142 or 143... 

Treatment with sodium hypochlorite or hypobromite converts primary amines into N-halo- or N,N-dihaloamines. Secondary amines can be converted to N-halo secondary amines. Similar reactions can be carried out on unsubstituted and N-substituted amides and on sulfonamides. With unsubstituted amides the N-halo-gen product is seldom isolated but usually rearranges (see 18-13) however, N-halo-N-alkyl amides and N-halo imides are quite stable. The important reagent NBS is made in this manner. N-Halogenation has also been accomplished with other reagents, (e.g., sodium bromite NaBr02) benzyltrimethylammonium tribromide (PhCH2NMe3 Br3"), and NCS. The mechanisms of these reactions involve attack by a positive halogen and are probably similar to those of 12-47 and 12-49.N-Fluorination can be accomplished by direct treatment of amines °° or... 

The imide nitrogen atom was also most reactive to a variety of electrophilic species (hydrogen halides, pseudohalogens, and alkyl halides) in the parent Rimidophosphazenes, R(C—NH)-N=PPh3. With t-butyl hypochlorite the /V-chloro-derivatives, R(C=NCl)-N=PPh3, were obtained. R/ -Vinyl-phenylphosphazenes have been prepared by condensation of aldehydes with active methylene compounds ... 

Anon. Chemical Engineer, 1996, (620), 4 ibid, 1996, (621), 7 A tanker of aqueous sodium chlorite was part charged to a tank of epichlorohydrin before it was reported it was mis-labelled. There was a very violent subsequent explosion, which blew down the wall of an adjacent factory. (The editor suspects it was, in fact, sodium hypochlorite, commonly known simply as hypochlorite, which sounds like epichlorohydrin. Sodium hypochlorite would be expected to be the more reactive of the two, generating an alkyl hypochlorite.)... 

Contact of these, or of chlorine and alcohols, readily forms unstable alkyl hypochlorites. 

---