Amount Of Nitric Acid Research Articles

Liquid‐phase oxidation of anthracene in acetic acid with an oxygen/Nitric acid system

AbstractOxidation of anthracene in acetic acid by the oxygen/nitric acid system has been studied and an attempt has been made to ascertain a practical limit of the amount of solvent keeping the commercial prospects in view. The effects of other reaction parameters such as flow rate, amount of nitric acid and water, residence time, etc., have been investigated. While opting for a solvent/substrate ratio of 10, the optimum conversion of anthracene to anthraquinone free from nitro‐compounds has been found to be 91% with purity of 98.7%, acceptable to dye‐stuff industries.

Studies on the uptake of Th(IV), U(VI) and Pu(IV) on Dowex 50WX8 resin from TBP-Shell Sol-T mixtures

Batch equilibration studies have been carried out to understand the uptake of Th(IV), U(VI) and Pu(IV) on a conventional gel type cation exchange resin, Dowex 50WX8, from TBP-Shell Sol-T mixtures containing different amounts of nitric acid. Based on the results of the equilibration studies, column experiments have been carried out and conditions optimized to achieve separation of these elements present in binary and ternary mixtures. The influence of water content of the resin phase and the nature of the exchanging cation on the extent of uptake has also been investigated.

Total amount of atmospheric HNO3above Mont-Louis

Describes the use of the corrective term of temperature for the determination of the amount of nitric acid from the ground. Discussions of the results and comparison between the present values and those obtained by different authors are presented.

Dissolution of niobium and tantalum matrix and their separation from trace elements by means of extraction with diantipyrylmethanes

The separation of niobium and tantalum as matrices from other elements that appear as trace impurities was systematically examined by extraction with diantipyrylmethane and hexyl-diantipyrylmethane. The decomposition of the matrices in the HF/HNO3 mixture was optimised by using the smallest possible quantities of nitric acid, because the presence of nitric acid hindered the efficiency of the separation. For the same reason the elimination of nitric acid from the sample solution by evaporation and also by decomposition with formic acid and urea was examined.

Some products from nitrosation of indoles

Nitrosation of 1-methylindole with an equimolar amount of nitrous acid gave 5-hydroxy-6,11-dimethylpyrrolo-[2,3-b:4,5-b′]di-indole, and with an excess of nitrous acid 5,11-dimethylpyrazino[2,3-b:5,6-b′]di-indole 6-oxide. Nitrosation of 1-methylindol-3-yl phenyl sulphide gave diphenyl disulphide (23%), 1-methyl-2,3-bis(phenylthio)indole (2.5%), 1-methyl-2-nitroindol-3-yl phenyl sulphide (13%), 1-methyl-3,3-bis(phenylthio)-indolin-2-one (8%), and 1-methyl-3-nitroindole (6%). The formation of these products from nitrosation can be explained by initial electrophilic attack on both free and 3-substituted indoles at the 3-position.

Destruction of concrete by nitrification

Nitrification was studied, using samples of asbestos concrete plates and water, both taken from a cooling tower, in which ammonia-containing water had been circulated for several years. Almost the entire nitrifying activity and the majority of autotrophic nitrifying bacteria were found to be located in the coating, covering the asbestos concrete plates. When sprinkled over these plates, the H+-concentration of such ammonia-containing water increased from neutrality to about pH 5.3 and this pH was maintained as long as nitrification was feasible. Death of microorganisms and lack of either ammonia or oxygen caused a rapid decrease of H+-concentration, which was obviously due to concrete destruction. The temporary acidification observed in the medium resulted from both acid-producing microbial nitrification and acid consuming concrete dissolution, with both reactions counteracting each other. The amount of nitric acid required to maintain a low pH in presence of concrete was determined by automatic titration. The obtained result indicated that considerable amounts of nitric acid might have been formed in the cooling system, which could well account for the observed damage.

The extraction of excess nitric acid and water by tri-(long-chain)-alkyl amine nitrates in organic diluents

An explanation is presented for the extraction of excess nitric acid and water by trilaurylamine nitrate in dodecane, xylene and chlorobenzene. Applying the computer Fortran IV-MIN program to a series of three successive extractions, a best fitting curve to the experimental data has been obtained. Although the amount of nitric acid per amine molecule steadily increases, water is replaced from the amine nitrate molecule by the first excess nitric acid uptake and next coextracted to a limiting amount when additional excess acid is bound. The acceptable description of the excess acid and water extraction is based on the aggregation of the amine nitrate species. By vpl (vapour pressure lowering) an average value of ι = 1·6 in chlorobenzene and ι = 2·3–3·3 in o-xylene have been measured, these values being independent of the aqueous nitric acid concentration between 1 2 and 6 M. It was found that the species finally formed in all solvents have the same average composition. An indication of the gross composition of the main species formed in chlorobenzene, xylene and dodecane has been given.

Behavior of lignin models on nitration

1. The behavior of eight lignin models under the action of concentrated nitric acid in a carbon tetrachloride medium was studied; the models were derivatives of 1-(3,4-dlmethoxyphenyl)- and 1-(4-hydroxy-3-methoxyphenyl)-propane containing a hydroxy group in various positions in the propane chain. 2. In the nitration of models having an etherified phenolic hydroxyl [(3,4-dimethoxyphenyl)propanols], one nitro group entered the nucleus in the 6-position. The action of nitric acid favored also the condensation of the alcohol in which the OH was in the 1-position of the side chain, and it oxidized the alcohol group of 1-(3,4-dimethoxyphenyl)-2-propanol to a keto group. 3. When treated with nitric acid under similar conditions, models with a free phenolic hydroxyl in the para position to the side chain (derivatives of 4-propylguaiacol) behave differently: 1-(4-hydroxy-3-methoxyphenyl)-1-propanol, treated with excess of nitric acid (3 molecular proportions), loses its side chain and gives 4,6-dinitroguaiacol; under the action of a smaller amount of nitric acid 4,6-dinitroguaiacol is accompanied by some dimeric condensation product. When 3-methoxyphenyl)-1-propanol is nitrated, a light-brown powder containing nitrogen is formed. 4. The behavior of the models in nitration indicates the great variety of the process that occur when lignin is treated with nitric acid, for all the types of models studied are present in lignin as structural units.

29—A SEMI-MICRO METHOD OF HIGH ACCURACY FOR THE DETERMINATION OF SULPHUR IN WOOL

An accurate method, based on many hundred assays, is given for the determination of sulphur in samples of approximately 0·2 g of wool. It gives highly repeatable results, as evidenced by the small range of 3·21—3·32% sulphur with a standard error of 0·003%, for 61 determinations on a Merino top and the quantitative recovery of wool sulphur in the presence of potassium sulphate. The analytical procedure involves the wet oxidation of the sulphur to sulphuric acid by a nitric–perchloric acid mixture, and the subsequent precipitation and weighing of barium sulphate. The use of potassium dichromate as a catalyst for the oxidation, and as an indicator for its end point is discussed. The rate of the oxidation and the quantity of nitric acid required are critical as slow oxidations produce low results. Excess perchloric acid or potassium dichromate interferes with the precipitation of barium sulphate through solubility and co-precipitation effects. The methods for addition of barium chloride, aggregation and filt...

DIMETHYLDINITROÖXAMIDE

A practical low-cost method is described for the preparation of the explosive dimethyldinitroöxamide. Dimethyloxamide is prepared in 94% yield from an oxalic ester and methylamine, and then is nitrated in 98% yield with slightly more than the requisite amount of nitric acid. The nitrating acid can be recovered safely. The optimum yield is obtained when the waste acid has the composition sulphuric acid monohydrate.

Researches on the alkoxy‐amino‐nitrobenzenes. III: Nitration of 1‐alkoxy‐2‐aminobenzenes and 1‐alkoxy‐2‐acetylaminobenzenes

AbstractNitration of 1‐alkoxy‐2‐acetylaminobenzenes with an excess of nitric acid, sp. gr. 1.40, leads to a mixture of the 4‐nitro and the 5‐nitro derivative, in which the latter substance predominates.Nitration of 1‐alkyloxy‐2‐aminobenzenes or 1‐alkyloxy‐2‐acetylaminobenzenes with the calculated amount of nitric acid in concentrated sulphuric acid gives the 4‐nitro derivative as the sole or practically sole nitration product.The results obtained in the nitration are discussed from a theoretical point of view.

On indigo. I. The nitration of indigo

AbstractWhen indigo was nitrated with absolute nitric acid, either directly or dissolved in sulphuric acid or acetic acid only decomposition products, containing nitrated isatins, could be obtained, but when indigo was nitrated in acetic anhydride, well defined products could be prepared. These were derivatives of 2‐acetoxy‐3: 3'‐diketo‐diindolinyl‐2: 2' into which one, two or three nitro groups were introduced, depending on the amount of nitric acid used. on heating, these compounds split off a molecule of acetic acid and mono‐, di‐, or tri‐nitroindigos remained behind. An analogous result was obtained, when indigo was nitrated in butyric anhydride. Indigo could also be nitrated in acetyl chloride but 5‐chloroisatin was then obtained.

The influence of weather conditions upon the amounts of nitric acid and of Nitrous acid in the Rainfall at and near melbourne, Australia

The influence of weather conditions upon the amounts of nitric acid and of Nitrous acid in the Rainfall at and near melbourne, Australia

On the Chemical Changes Produced in Flour by Bleaching

The action of air containing nitrogen peroxide upon flour, in quantities up to 300 c.c. of nitrogen peroxide to one kilogramme of flour, may be summarised as follows:—I. The golden-yellow tint of the flour is destroyed. Immediately after bleaching no difference in tint due to excess of the bleaching agent could be observed with Lovibond's tintometer, but on keeping for several days the more highly bleached samples became decidedly yellow, while those treated with 30 to 100 c.c. of nitrogen peroxide per kilogramme became still whiter, the maximum of bleaching effect being attained within these limits.II. The amount of nitrous acid or nitrites present in a freshly bleached flour is approximately proportional to the amount of nitrogen peroxide employed, and corresponds to about 30% of the total nitrogen absorbed, rising to 40% in the more highly bleached samples. After the lapse of several days, the proportion of nitrites present decreases considerably in the higher concentrations, but remains very nearly the same in the more slightly bleached samples.III. Approximately 60% of the total nitrogen introduced as nitrogen peroxide into the flour during bleaching can be recovered as ammonia a short time after bleaching by reducing the aqueous extract of the flour with a copper-zinc couple, and may be assumed to be present in the flour as nitric and nitrous acids or as nitrates and nitrites. After keeping the bleached flour for some days the amount of nitric acid extracted with cold water decreases. Experiments with pure glutenin and gliadin indicated that in certain circumstances nitric acid may be withdrawn from solution or “adsorbed” by these proteins.IV. In highly bleached flour a considerable increase in the amounts of soluble proteins and soluble carbohydrates takes place. If one kilogramme of flour is bleached with 300 c.c. of nitrogen peroxide, the amount of soluble nitrogen is doubled. This appears to be due almost entirely to the solubility of gliadin in nitric acid of certain concentrations. The simultaneous increase of soluble carbohydrates would seem to point to an intimate relationship between the gliadin and certain carbohydrates in flour.V. If highly bleached flour is allowed to stand for some time after bleaching, the oil undergoes very considerable alteration and acquires the characteristics of an oxidised oil. About 6 to 7% of the nitrogen introduced as nitrogen peroxide during bleaching is absorbed by the oil.VI. The absorption of nitrogen peroxide by flour does not appear to be accompanied by the production of free nitrogen, nor was any evidence obtained of the formation of diazo-compounds.VII. Sodium nitrite was found to exert no inhibitory action on the digestion of soluble starch by saliva, but the rate of digestion was greatly retarded if the starch had been previously treated with nitrogen peroxide gas. Bleaching was found to exercise an inhibitory effect on the salivary digestion of flour.

British Food Journal Volume 13 Issue 6 1911

In the second part of this report the action of nitrogen peroxide on flour is discussed at some length in an account of a series of researches that have been carried out by DR. MONIER‐WILLIAMS. His conclusions may be briefly stated as follows. The maximum bleaching effect is obtained when each kilogram of flour is treated with from 30 to 100 cubic centimetres of nitrogen peroxide. The bleaching effect becomes more pronounced after keeping for several days. The amount of nitrous acid or nitrites that are present in bleached flour corresponds to about 30 per cent. of the total nitrogen absorbed, the proportion of nitrites present remaining nearly constant after the lapse of several days in the more slightly bleached samples. After the lapse of a short time it is still possible to extract about 60 per cent. of the nitrogen absorbed by the flour by means of cold water, but after several days the nitrogen that can be extracted by this means decreases. This may perhaps be attributed to the “absorption” of nitrous acid by the glutenin and gliadin. In highly bleached flour (300 cubic centimetres of nitrogen peroxide per kilogram of flour) a considerable increase in the amounts of soluble proteins and soluble carbohydrates takes place. In highly bleached flour, after some time, about 6 or 7 per cent. of the nitrogen introduced as nitrogen by the nitrogen peroxide is absorbed by the oil, which acquires the characteristics of an oxidised oil. No evidence is forthcoming as to the formation of diazo compounds nor the production of free nitrogen. Bleaching was found to exercise an inhibitory action on the salivary digestion of flour.

THE EFFECTS OF THE INHALATION OF THE FUMES OF NITRIC ACID.WITH REPORT OF CASES.

The Denver Fire Department was called to the office of theDenverPost Sept. 20, 1904, at 4 p. m. On arrival they were informed that a carboy of nitric acid had been accidentally broken in an attempt to remove the stopper with a hammer. The acid spread across the floor, coming in contact with the zinc used in etching. Sawdust was used to absorb it, and, rapidly oxidizing, burst into flame here and there, resulting in the call for the firemen. Mr. Bradt, foreman of the department, who was at work in the room, states that the fumes and smoke were not especially irritating until the portable apparatus began playing on the fire, the usual carbonic acid-producing solutions being employed. We find by examination that the acid used contained no appreciable amount of nitrous acid and was of about 38 per cent. strength. About ten gallons of it escaped

VIII. The variations of electromotive force of cells consisting of certain metals, platinum, and nitric acid

The experiments described by one of us in another paper have established that the necessary condition for the chemical reactions between nitric acid and the metals copper, mercury, and bismuth, is the presence and continuous formation of nitrous acid. These results confirm the previous observations of Russell in the case of the metal silver. Further, it has been shown that when these metals are introduced into purified nitric acid, no apparent change takes place at first, but after some time gas bubbles are seen to rise from the surface of the metal, and the liquid then contains an amount of nitrous acid which can be detected by the more delicate reagents. The amount of this acid increases up to a maximum and constant point, while concomitantly the amount of metal dissolved per unit of time equally increases to a maximum and constant value. It seemed, therefore, desirable to ascertain if these phenomena determined by the balance are correlated with any alteration of electromotive force. To avoid any misunderstanding, however, it would be advisable at the outset to state that this paper is separated from that of one of us “On the Condition of Chemical Change between certain Metals and Nitric Acid,” rather on account of division of labour than of difference of subject. The idea of measuring the electromotive force of cells consisting of platinum, certain metals, and nitric acid occurred to the latter of us, while the apparatus and method of measurement finally adopted are due solely to the former. Previous Investigations . Many years ago Faraday pointed out that neither nitrogen peroxide nor nitric acid are conductors when pure, but that the addition of water to the former, or of nitrous acid to the latter, produces the property of conductivity “in a very high degree among electrolytes.” Thus the presence of nitrous acid is the necessary condition that nitric acid should become an electrolyte. Again, Faraday proved that the electric position of certain pairs of metals in nitric acid is varied according to the conditions of concentration and temperature; in fact, experiments on this point were considered by him to be of especial importance in confirming the chemical and disproving the contact theory of the voltaic cell.

L.—The amount of nitric acid in the rain-water at Rothamsted, with notes on the analysis of rain-water

L.—The amount of nitric acid in the rain-water at Rothamsted, with notes on the analysis of rain-water