Ferric chloride with hydrogen peroxide

Isopropylidene or benzylidene 2-hydrazinoselenazole derivatives can be converted to highly colored 2.2 -dioxo-A-3,3 -biselenazol-5,5 -inylidene-bis-hydrazones (Table X-11) by oxidation with ferric chloride and hydrogen peroxide i33). 

Thiazolidine-4-carboxylic acid is not stable in the presence of reducing agents, e.g. sodium in liquid ammonia 193 and, in contrast to N-protected Thz, the N-unprotected forms are unstable under oxidizing conditions, e.g. slow ring opening occurs in air at pH 10 in the presence of traces of ferric chloride, or, more rapidly, with hydrogen peroxide, bromine, or iodine in aqueous solution. 190 ... 

Benzoyl disulfide has been obtained by the reaction of benzoyl chloride with hydrogen sulfide, hydrogen disulfide, hydrogen trisulfide, potassium sulfide, sodium disulfide, lead sulfide, sodium hydrosulfite, sodium thiosulfate, sulfhydrylmagnesium bromide, and thiobenzamide. It is also formed by reaction of benzoic anhydride with hydrogen sulfide. The better preparative methods involve the oxidation of thiobenzoic add by means of air,hydrogen peroxide or sulfur monochloride, or of the sodium or potassium salt by means of air, - chlorine, iodine, copper sulfate, - potassium ferricyanide, - or ferric chloride. - ... 

Dehydrogenation of 2-amino-3,4-dihydroquinoxaline to 2-aminoquinoxaline is effected smoothly by reaction with hydrogen peroxide in combination with a trace amount of ferrous chloride, ferric sulfate, or lead dioxide as carrier. Details are... 

In SMOBC processing, the metal-plated resist is removed to present a flat, clean copper surface for solder mask definition. Tin/lead alloys can be stripped in oxidizing fluoride solutions such as fluoboric acid and hydrogen peroxide or ammonium bifluoride with hydrogen peroxide or nitric acid. (Caution machine construction must be made compatible with fluorides by elimination of titanium and glass components.) Commercial formulations are available to be used inline after the etch machine rinses. Accumulations of spent solution or filtered lead-fluoride deposits must be treated as hazardous waste and have been accepted by solution vendors for treatment and disposal costs. Modern applications usually use lead-free tin plating resists, which can be fluoride containing as previously discussed, or compounds of ferric chloride... 

Minerals which also contain iron will yield ferrous ions when fused with zinc chloride and they too give a red color with dimethylglyoxime and ammonia (compare page 267). Consequently, in such cases it is best to test for ferrous silicates as outlined on page 563 and if the response is positive the ammoniacal suspension should be warmed with hydrogen peroxide prior to the centrifuging. Ferric hydroxide is precipitated, while the nickel tetram-mine ions remain in solution. 

Chemical Properties. The most significant chemical property of L-ascorbic acid is its reversible oxidation to dehydro-L-ascorbic acid. Dehydro-L-ascorbic acid has been prepared by uv irradiation and by oxidation with air and charcoal, halogens, ferric chloride, hydrogen peroxide, 2,6-dichlorophenolindophenol, neutral potassium permanganate, selenium oxide, and many other compounds. Dehydro-L-ascorbic acid has been reduced to L-ascorbic acid by hydrogen iodide, hydrogen sulfide, 1,4-dithiothreitol (l,4-dimercapto-2,3-butanediol), and the like (33). 

The most suitable oxidizing agent is potassium ferricyanide, but ferric chloride, hydrogen peroxide ia the presence of ferrous salts, ammonium persulfate, lead dioxide, lead tetraacetate or chromate, or silver and cupric salts may be useful. Water mixed, eg, with methanol, dimethylformamide, or glycol ethers, is employed as reaction medium. 

Manganous sulphate5 and ferric salts in general accelerate the decomposition of hydrogen peroxide.6 The sulphate is less active than the chloride or nitrate. With dilute solutions of the salts the effect is proportional to the concentration of the peroxide and that of the iron ions, whilst in the presence of acids it is inversely proportional to the hydrogen-ion concentration. The temperature coefficient of the reaction is 3 25 for ten degrees. ... 

Ferrous sulphide is oxidised by acidulated hydrogen peroxide solution, yielding ferric sulphate or hydrolysed products of this salt.1 With ammoniacal zinc chloride no reaction occurs at the ordinary temperature, but at 160° to 170° C. in a sealed tube ferrous hydroxide and zinc sulphide are produced.2... 

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