Perchloric acid , oxidation with

Percussion mortar 155 Perchloric acid oxidation with, 112 titration with (nonaqueous), 408 Periodates, D. of as silver iodide, (g) 483 Peroxides analysis of, (ti) 373 Persistent lines 759... 

Presumably perchloric acid oxidizes the steroids at ring A and these then form charge transfer complexes with picric acid. 

Digest with nitric acid oxidize with hydrogen peroxide at 450°C to destroy organic matter digest with sulfuric and hydrofluoric acids, followed by digestion with nitric, sulfuric, and perchloric acids... 

Under suitable conditions, further oxidation of the coupled products produces isolable dimer cation radicals. Thus treatment of 9-alkylcarbazoles with lead tetracetate in acetic acid-perchloric acid, or with 2,3-dichloro-5,6-dicyano-p-benzoquinone in acetic acid-perchloric acid, or with tris-(p-bromophenyl)ammoniumyl perchlorate in methylene chloride, or with nitrosonium borofluoride in acetonitrile all gave isolable cation radical perchlorates such as 17. These were reducible with aqueous sodium dithi-onite to the corresponding bicarbazoles the dimer cation radicals could be produced again by reoxidation of the dimer using 2,3-dichloro-5,6-dicyano-p-benzoquinone in acid solution. ... 

An interesting variant uses acyl- or aroyl-methylpyridinium salts with ammonia or an amine to produce dipyridiniumdihydropyridine salts (655). With aromatic aldehydes the dihydropyridines are produced directly or the intermediate (654) can be isolated and subsequently treated with perchloric acid (75LA849). With formaldehyde (giving dihydropyridines without a substituent in position 4), the 1,5-diketone can be isolated and cyclized by ammonia (75LA864). The dipyridinium salts (655) undergo some useful transformations they can be oxidized to pyridines (656), and these dipyridinium pyridine salts give... 

The preparation of dibenzo[6,e ][ 1,4]dioxin cation radical (66) has been achieved by oxidation of the heterocycle in ethyl acetate-lithium perchlorate at a platinum anode, using a controlled potential of 1.2 volts vs. Ag-AgC104. The blue solid collected at the anode contained between 85-90% of (66) as the perchlorate (74JHC139). The purple cation radical perchlorate of phenoxathiin, (67), is obtained in high purity by oxidation of phenoxathiin in benzene with 70% perchloric acid-acetic acid (75JOC2756). Similar perchloric acid oxidation of thianthrene affords the dark reddish brown perchlorate of (68) (69JOC3368) and the heterocycle can also be oxidized on a preparative scale with antimony pentachloride (62JCS4963). 

The chemistry of perchloric acid along with its applications has been well reviewed.5 The main use of perchloric acid has been the use of its salts (such as NH4 1 CI04 ) as powerful oxidants in pyrotechniques and rocket fuels. 

A common mistake is to use too little perchloric acid even with acid soluble materials posing no particular difficulty, there is considerable energy given off during the actual perchloric oxidation, and the acid is both consumed as oxidant and vigorously boiled off. If the total amount of acid available is insufficient, the mixture will go to dryness before the oxidation is complete and the dry residues will catch fire. True explosions on the 1—2 g sample scale are rare at this stage, but the beaker may shatter because of the thermal shock, and in any case the analysis will be ruined. 

ACETYL PROPANE (563-80-4) CjHioO Highly flammable liquid. Forms explosive mixture with air [explosion limits in air (vol %) 1.2 to 8.0 flash point 26°F/-3°C 43°F/6°Cl autoignition temp 887°F/475°C]. Reacts violently with strong oxidizers, aldehydes, nitric acid, perchloric acid. Incompatible with acids, anhydrides,... 

METHYL AZINPHOS (86-50-0) (86-50-0) CioHjiNjOjPS, Combustible solid or liquid in an organic carrier solvent (see also entry for that specific carrier solvent). Hydrolyzes in water the process accelerates under alkaline conditions. Inconq)atible with perchloric acid. Contact with strong oxidizers may cause fire and explosions. Unstable at temperatures above 392°F/200°C when exposed to elevated temperatures, the containers may explode. On small fires, use dry chemical powder (such as Purple-K-Powder), foam, water spray, or CO2 extinguishers. Thermal decomposition releases toxic nitrogen oxides, phosphoms oxides, and sulfur oxides. 

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