Sodium hypochlorite, formation oxide

Sodium hydride, 5 10 dispersions of, 6 13 Sodium hypochlorite, formation of, in preparation of chlorine(I) oxide, 6 159re. solution of, 1 90... 

Anhydrous zinc chloride can be made from the reaction of the metal with chlorine or hydrogen chloride. It is usually made commercially by the reaction of aqueous hydrochloric acid with scrap zinc materials or roasted ore, ie, cmde zinc oxide. The solution is purified in various ways depending upon the impurities present. For example, iron and manganese precipitate after partial neutralization with zinc oxide or other alkah and oxidation with chlorine or sodium hypochlorite. Heavy metals are removed with zinc powder. The solution is concentrated by boiling, and hydrochloric acid is added to prevent the formation of basic chlorides. Zinc chloride is usually sold as a 47.4 wt % (sp gr 1.53) solution, but is also produced in soHd form by further evaporation until, upon cooling, an almost anhydrous salt crystallizes. The soHd is sometimes sold in fused form. 

The pH of the chlorine dioxide reaction mixture must be maintained in the 2.8—3.2 pH range, otherwise decreased conversion yields of chlorite to chlorine dioxide are obtained with by-product formation of chlorate. Generator efficiencies of 93% and higher have been demonstrated. A disadvantage of this system is the limited storage life of the sodium hypochlorite oxidant solution. 

In comparison to N—S bond formation, O—N bond formation by essentially oxidative procedures has found few applications in the synthesis of five-membered heterocycles. The 1,2,4-oxadiazole system (278) was prepared by the action of sodium hypochlorite on A(-acylamidines (277) (76S268). The A -benzoylamidino compounds (279) were also converted into the 1,2,4-oxadiazoles (280) by the action of r-butyl hypochlorite followed by base. In both cyclizations A -chloro compounds are thought to be intermediates (76BCJ3607). 

During an attempt at destroying benzyl cyanide residues with sodium hypochlorite, a detonation was caused that was probabiy due to the formation of nitrogen trichloride. However, it might be asked if it was not due to the nitrile group oxidation by the hypochlorite present. 

Another interesting class of five-membered aromatic heterocycles has recently been published by Tron et al. [54]. These compounds have biological activity in the nM range. An example of the formation of these furazan (1,2,5-oxadiazole) derivatives is shown in Scheme 9. The diol 50 was oxidized to the diketone 51 using TEMPO and sodium hypochlorite. Transformation to the bisoxime 52 was performed in an excess of hydroxylamine hydrochloride and pyridine at high temperature for several days. Basic dehydration of 52 formed two products (53a and b). A Mitsunobu reaction was then employed using toluene as solvent to form compound 53b in 24% yield. 

As indicated above (Ohme and Schmitz [38a, p. 339]) primary amines converted into the alkylamides of sulfuric acid can be oxidized with sodium hypochlorite to azo compounds. The reaction appears to proceed by way of an intermediate hydrazine, which is ultimately oxidized [38a], The reaction is suitable for the formation of symmetrically substituted azoalkanes. Highly branched primary aliphatic amines have been oxidized with sodium hypochlorite in an aqueous dioxane medium [77],... 

Nevertheless, in some azoles the energies of n- and upper ir-orbitals are probably comparable and in such cases A-oxide formation is observed. Thus, 1-methylpyrazole is oxidized by peracetic acid to the 2-oxide in 10% yield. 1-Substituted 1,2,3-triazoles are oxidized by MCPBA at the more basic N(3) to give the corresponding triazole IV-oxides. The yield is lower if an electron-withdrawing substituent is present at the C(4) or C(5) position (87ACS(B)724). Reaction of 3-methylbenzisoxazole (119) with sodium hypochlorite or lead tetraacetate gave the 2-oxide (120) in 70 and 90% yields, respectively <87H(26)2921>. 

N—O bond formation by oxidative procedures has found less application. However, the 1,2,4-oxadiazole system (450) can be prepared by the action of sodium hypochlorite on N-acylamidines (449) (76S268). 

Another synthetic method involves treating the parent aromatic hydrocarbon with sodium hypochlorite in water-chloroform, using phase transfer agents like tetrabutylammonium hydrogen sulfate or benzyltrimethylam-monium chloride.15 The epoxides are formed in high yields. The rate is pH dependent, and epoxide formation is most facile at pH 8-9. Many K-region arene oxides like 1,165, acenaphthylene 1,2-oxide (19), 1-azaphenanthrene 5,6-oxide (20), 4-azaphenanthrene 5,6-oxide (21), 1,10-phenanthroIine 5,6-oxide... 

Both hypochlorous acid and the hypochlorites are relatively unstable and decompose readily with liberation of oxygen and the formation of chlorides. In fact, the acid is known only in solution. These compounds are excellent oxidizing agents they are used as bleaching agents, as antiseptics, as disinfectants, and in the production of ethylene glycol. The commercial production of sodium hypochlorite by electrolysis has been described previously. 

The electrolysis step produces sodium hydroxide (NaOH) at the cathode and chlorine (Cl2) at the anode, and mixing occurs with the formation of sodium hypochlorite (NaOCl) that is oxidized to chlorate. 

Oxidation of internal perfluoroolefins by alkaline solutions of hydrogen peroxide and alkaline and alkaline-earth hypohalides leads to the formation of olefin oxides, the yield of the target product being 40-50%. The reaction with sodium hypochlorite in an alkali in the presence of acetonitrile is an example of epoxidation performed by the nucleophilic attack of the OC1-anion of the multiple bond with further elimination of the chloride anion by the intermediate carbanion (79IZY2509, 79IZV2812, 79RP666176,... 

The treatment of isatin with sodium hypochlorite in acetic acid leads to 1-chloroisatin, an effective mild oxidizing agent for the conversion of alcohols to aldehydes and ketones110 and of indoles to 3-chloroindoles without formation of by-products111. N-[phenyliodine(III)] bisisatin can be obtained from the sodium salt of isatin and phenyliodine (IE) bistrifluoroacetate in 85% yield. This compound is a member of a group of iodine(III)imides,... 

Barton oxidation was the key to form the 1,2-diketone 341 in surprisingly high yield, in order to close the five-membered ring (Scheme 38). The conditions chosen for the deprotection of the aldehyde, mercuric oxide and boron trifluoride etherate, at room temperature, immediately led to aldol 342. After protection of the newly formed secondary alcohol as a benzoate, the diketone was fragmented quantitatively with excess sodium hypochlorite. Cyclization of the generated diacid 343 to the desired dilactone 344 proved very difficult. After a variety of methods failed, the use of lead tetraacetate (203), precedented by work performed within the stmcmre determination of picrotoxinin (1), was spectacularly successful (204). In 99% yield, the simultaneous formation of both lactones was achieved. EIcb reaction with an excess of tertiary amine removed the benzoate of 344 and the double bond formed was epoxidized with peracid affording p-oxirane 104 stereoselectively. Treatment of... 

Nitriles are also the usual products of oxidation of aliphatic amines RCH2NH2 by nickel peroxide and lead(IV) acetate. Aliphatic azo compounds can be prepared from these primary amines by first converting them into ulfamides (6), these then being oxicUzed with sodium hypochlorite or (better) r-butyl hypochlorite (Scheme 9). A few aliphatic azo compounds can be formed in good yield by direct oxidation of f-alkylamines for example, AIBN was formed (86%) by oxidation of the amine Me2C(CN)NH2 with sodium hypochlorite. A special case of azoalkane formation is the synthesis of chlorodiazirines (7) from amidines RC(=NH)NH2 by oxidation with sodium hypochlorite. ... 

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