Benzene oxides with thiocyanate

Cyanide and thiocyanate anions in aqueous solution can be determined as cyanogen bromide after reaction with bromine [686]. The thiocyanate anion can be quantitatively determined in the presence of cyanide by adding an excess of formaldehyde solution to the sample, which converts the cyanide ion to the unreactive cyanohydrin. The detection limits for the cyanide and thiocyanate anions were less than 0.01 ppm with an electron-capture detector. Iodine in acid solution reacts with acetone to form monoiodoacetone, which can be detected at high sensitivity with an electron-capture detector [687]. The reaction is specific for iodine, iodide being determined after oxidation with iodate. The nitrate anion can be determined in aqueous solution after conversion to nitrobenzene by reaction with benzene in the presence of sulfuric acid [688,689]. The detection limit for the nitrate anion was less than 0.1 ppm. The nitrite anion can be determined after oxidation to nitrate with potassium permanganate. Nitrite can be determined directly by alkylation with an alkaline solution of pentafluorobenzyl bromide [690]. The yield of derivative was about 80t.with a detection limit of 0.46 ng in 0.1 ml of aqueous sample. Pentafluorobenzyl p-toluenesulfonate has been used to derivatize carboxylate and phenolate anions and to simultaneously derivatize bromide, iodide, cyanide, thiocyanate, nitrite, nitrate and sulfide in a two-phase system using tetrapentylammonium cWoride as a phase transfer catalyst [691]. Detection limits wer Hi the ppm range. 

Intermediates in Reactions.—The desulphurization of thiepins is believed to proceed by ring contraction to a thiiran. Treatment of benzene oxide-oxepin with thiocyanate ion did not yield benzene sulphide-thiepin, but rather gave benzene, possibly by desulphurization of the unstable benzene sulphide. The synthesis of l,6 8,13-bismethano[14]annulene involves extrusion of a sulphur atom via an intermediate thiiran, and the photolysis of 4-phenylisothio-chromene to 3-phenylindene likewise involves a thiiran (Scheme 2). The... 

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 45, 71 Sodium amide, in alkylation of ethyl phenylacetate w ith (2-bromo-ethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1 bromobutane to give 2,4-nonanedione, 47, 92 Sodium 2 ammobenzenesulfinate, from reduction of 2 mtrobenzenesul-finic acid, 47, 5... 

Popova and colleagues47 carried out TLC of oxidation products of 4,4 -dinitrodiphenyl sulphide (the sulphoxide and sulphone) on silica gel + a fluorescent indicator, using hexane-acetone-benzene-methanol(60 36 10 l) as solvent mixture. Morris130 performed GLC and TLC of dimethyl sulphoxide. For the latter, he applied a 6% solution of the sample in methanol to silica gel and developed with methanol-ammonia solution(200 3), visualizing with 2% aqueous Co11 thiocyanate-methanol(2 1). HPLC separations of chiral mixtures of sulphoxides have been carried out. Thus Pirkle and coworkers131-132 reported separations of alkyl 2,4-dinitrophenyl sulphoxides and some others on a silica-gel (Porosil)-bonded chiral fluoroalcoholic stationary phase, with the structure ... 

In a different study, anthracene, phenanthrene, perylene 93 (Fig. 31), and 2,7-di-tert-butylpyrene underwent regioselective oxidative-substitution reactions with iodine(III) sulfonate reagents in dichloromethane to give the corresponding aryl sulfonate esters. The use of [hydroxy(tosyloxy)iodo]benzene, in conjunction with trimethylsilyl isothiocyanate, led to thiocyanation of the PAH nucleus. 

CALCIUM CHLORITE (14674-72-7) A strong oxidizer. Violent reaction with reducing agents, alcohols, combustible materials, ethers, organic substances, finely divided metals, strong acids. Reacts with acrolein, alcohols, antimony trisulfide, antimony tritelluride, arsenic pentasulfide, 1,1-dichloro-l-nitroethane, 1,3-dichloropropene, diethylamine,. r-trioxane. Reacts with chlorine, forming explosive material. Incompatible with m-bis-(trichlormethyl)benzene, potassium thiocyanate. 

CHLORINE FLUORIDE OXIDE (7616-94-6) Noncombustible, but many chemical reactions can cause fire and explosions. A powerful oxidizer. Reacts violently with reducing materials, alcohols, alkalis, amines, anilines, benzene, butyl-amine, calcium hydride, calcium acetylide, charcoal, combustible materials, ethers, hydrazine, hydrogen sulfide, finely divided metals, nitric oxide, olefins, orgtinic substances, potassium cyanide, potassium thiocyanate, sodium, strontium hydride, sulfur, sulfur dichloride, sulfuric acid. Incompatible with hydrogen sulfide, potassium thiocyanate, vinylidene chloride. Forms heat-, friction-, and shock-sensitive explosives with calcium hydride, nitrogenous bases, isopropylamine. Attacks some plastics, rubber, and coatings. 

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