Oxidation, by nitric acid

Usually prepared by the action of NaCN on benzaldehyde in dilute alcohol. It is oxidized by nitric acid to benzil, and reduced by sodium amalgam to hydrobenzoin PhCHOHCHOHPh by tin amalgam and hydrochloric acid to des-oxybenzoin, PhCH2COPh and by zinc amalgam to stilbene PhCH = CHPh. It gives an oxime, phenylhydrazone and ethanoyl derivative. The a-oxime is used under the name cupron for the estimation of copper and molybdenum. 

CCls CHO. A colourless oily liquid with a pungent odour b.p. 98°C. Manut actured by the action of chlorine on ethanol it is also made by the chlorination of ethanal. When allowed to stand, it changes slowly to a white solid. Addition compounds are formed with water see chloral hydrate), ammonia, sodium hydrogen sulphite, alcohols, and some amines and amides. Oxidized by nitric acid to tri-chloroethanoic acid. Decomposed by alkalis to chloroform and a methanoate a convenient method of obtaining pure CHCI3. It is used for the manufacture of DDT. It is also used as a hypnotic. 

CgHgO, PhCH = CHCOiH. Colourless crystals. Decarboxylales on prolonged heating. Oxidized by nitric acid to benzoic acid. Ordinary cinnamic acid is the trans-isomer, m.p. 135-136 C on irradiation with u.v. light it can be isomerized to the less stable cis-isomer, m.p. 42" C. 

Glycerol -dichlorohydrin, 2.3-dichloro-propanol, CH2CI CHC1 CH2 0H. Colourless liquid, b.p. 182 C. Prepared by the chlorination of propenyl alcohol. Oxidized by nitric acid to 1,2-dichloropropionic acid. Reacts with NaOH to give epichlorohydrin. 

Nitrations can be performed in homogeneous media, using tetramethylene sulfone or nitromethane (nitroethane) as solvent. A large variety of aromatic compounds have been nitrated with nitronium salts in excellent yields in nonaqueous media. Sensitive compounds, otherwise easily hydroly2ed or oxidized by nitric acid, can be nitrated without secondary effects. Nitration of aromatic compounds is considered an irreversible reaction. However, the reversibihty of the reaction has been demonstrated in some cases, eg, 9-nitroanthracene, as well as pentamethylnitrobenzene transnitrate benzene, toluene, and mesitylene in the presence of superacids (158) (see Nitration). 

Cyclohexane. The LPO of cyclohexane [110-82-7] suppUes much of the raw materials needed for nylon-6 and nylon-6,6 production. Cyclohexanol (A) and cyclohexanone (K) maybe produced selectively by using alow conversion process with multiple stages (228—232). The reasons for low conversion and multiple stages (an approach to plug-flow operation) are apparent from Eigure 2. Several catalysts have been reported. The selectivity to A as well as the overall process efficiency can be improved by using boric acid (2,232,233). K/A mixtures are usually oxidized by nitric acid in a second step to adipic acid (233) (see Cyclohexanol and cyclohexanone). 

Acidic Properties. As a typical acid, it reacts readily with alkaUes, basic oxides, and carbonates to form salts. The largest iadustrial appHcation of nitric acid is the reaction with ammonia to produce ammonium nitrate. However, because of its oxidising nature, nitric acid does not always behave as a typical acid. Bases having metallic radicals ia a reduced state (eg, ferrous and staimous hydroxide becoming ferric and stannic salts) are oxidized by nitric acid. Except for magnesium and manganese ia very dilute acid, nitric acid does not Hberate hydrogen upon reaction with metals. 

Nitrometer Method. The nitrometer method also is used to determine nitric acid or nitrates in mixed acid or oleum. It involves the measurement of the volume of NO gas that is Hberated when mercury is oxidized by nitric acid. The method is based on the following reaction ... 

In the second step, KA is further oxidized by nitric acid [7697-37-2] to adipic acid, which is separated, purified usually through crystallization, and dried (see Adipic acid). 

Bromine in chloroform and bromine in acetic acid are the reagents used most often to brominate pyrazole. When nitric acid is used as a solvent, both bromine and chlorine transform pyrazoles into pyrazolones (Scheme 24). Thus 3-methyl-l-(2,4-dinitrophe-nyOpyrazole is brominated at the 4-position (309). The product reacts with chlorine and nitric acid to give the pyrazolone (310). The same product results from the action of bromine and nitric acid on (311). The electrophilic attack of halogen at C-4 is followed by the nucleophilic attack of water at C-5 and subsequent oxidation by nitric acid. 

The action of hydroxylamine and sodium acetate in ethanol upon picryl chloride was stated to give 4,6-dinitrobenzofuroxan, and probably some of this compound was formed, although it was later shownthat much of the original work was faulty. A report that hydroxylamine and 2,4,5-trinitrotoluene give 5-methyl-6-nitro-benzofuroxan has been found to be incorrect. Benzofuroxan has not been prepared by V-oxidation of benzofurazan, and it seems unlikely that this could be achieved, since benzofuroxan itself is oxidizable by powerful reagents to o-dinitrobenzene (Section VI, B). A report of the oxidation by nitric acid of anthraceno[l,2-c]furazan to the furoxan is incorrectlv abstracted. 

Although gold is not oxidized by nitric acid, it can be brought into solution in aqua regia, a 3 1 mixture by volume of 12 M HC1 and 16 M HN03 ... 

Bordwell and Boutan (BB)81 carried out extensive work on the methylsulfmyl group in 1957. It must be emphasized that they found that the preparation of pure arylmethyl sulfoxides from arylmethyl sulfides by oxidation was not a trivial matter. The frequently recommended reagent, hydrogen peroxide in acetic acid, tended to give sulfoxides contaminated with appreciable quantities of sulfones, which could not be removed by fractional crystallization. Oxidation by nitric acid was found to be more satisfactory. 

Figure 1. Parts of the surface of source TEG (a, b) and TEG oxidized by sulfuric acid and subjected to thermal shock at 8000C (b) part of the surface of TEG particle oxidized by nitric acid and subjected to thermal shock at 80(fiC (d).

Curtis, 1968 1971 Curtis Cook, 1967). In accordance with this, an analogous Co(ra) complex is not oxidized by nitric acid there is no readily accessible higher oxidation state of the metal ion in this case. 

I. Gerber, M. Oubenali, R. Bacsa, J. Durand, A. Gonsalves, M. F. R. Pereira, F. Jolibois, L. Perrin, R. Poteau, P. Serp, Theoretical and experimental studies on the carbon-nanotube surface oxidation by nitric acid Interplay between functionalization and vacancy enlargement, Chem. Eur. J., vol. 17, pp. 11467-11477, 2011. 

Sb is oxidized by nitric acid, forming a gelatinous precipitate of bydrated antimony pentoxide. It does not react with cold dilute sulfuric acid. However, reaction occurs in bot concentrated acid an oxysulfate of indefinite composition and low acid-solubdity is formed. It reacts with bydrofluoric acid to form soluble antimony trifluoride and pentafluoride. Hydrochloric acid in the absence of air does not readily attack tbe metal however, finely divided antimony reacts with hot concentrated acid forming chloride salt. 

Nitrosyl chloride is oxidized by nitric acid to yield nitrogen dioxide, chlorine and water. 

The nitrous acid deamination of 2-amino-2-deoxy-D-mannose (8), in the favored conformation, the amino group ofwhich is axially attached, leads, in contrast, uniquely to D-glucose,15 characterized, after oxidation by nitric acid, as D-glucaric acid (9). This result has also been verified by direct crystallization of the D-glucose and by assay with D-glucose oxidase.44"... 

Oxidation, by nitric acid, 48 of aldehyde to carboxyl group, 49 of hydroxyl to carboxyl group, 49 of 2-methylquinoxaline to 2-methyl-pyrazine-5,6-dicarboxylic acid, 89 of quinoxaline to 2,3-pyrazinedicar-boxylic acid, 87... 

Cu No reaction with dilute acid oxidized by nitric acid to Cu2 (aq)... 

The occurrence of rims of lower reflectivity than the main mass of the particles after a short period of oxidation was unexpected and will require further investigation. Van Krevelen (13) illustrates vitrinite particles with oxidation rims that show a higher reflectivity than the remainder of the particles but does not mention the occurrence of particles with lower reflecting margins Illustrations of vitrinite particles oxidized by nitric acid however, in a recent paper by Edwards, Jones, and Newcombe (6), suggest that acid oxidation at... 

Smith387 studied the rate of oxidation of nitric oxide by nitric acid in the gas phase in the temperature range 263-363°K. The overall reaction was... 

A 2-alkoxyethanol with a fluorine-containing alkoxy group can be selectively oxidized by nitric acid to the 2-alkoxyacetic acid without cleavage of the ether bond, e.g. oxidation of 9 to 10.148... 

The reaction of pyridines and picolines with acetylenic compounds provides a useful synthesis of indolizines.48 The reaction of such compounds with dimethyl acetylenedicarboxylate (DMAD), originally investigated by Diels and co-workers (see Ref. 4) has been reexamined more recently by several groups.48-52 The two major adducts are now thought to be the quinolizines 26 and 27, although Wiley and Knabeschuh63 obtained the indolizine triester 28 when the reaction was carried out in ether as solvent. The adduct of type 27 is oxidized by nitric acid to 28. 

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