Small Amount Of Ammonia Research Articles

Overall reaction rates of NO and N 2 formation from fuel nitrogen

From measurements carried out on flat premixed hydrocarbon/oxygen argon (or helium) flames, into which small amounts of ammonia, or cyanogen are added, overall reaction rates of formation of NO and N2 are determined. From similar measurements effected on nitrogen-diluted ethylene/oxygen flames, an overall rate of prompt NO formation is obtained. The discussion of these rate constants indicates that the relative importance of HCN molecules as intermediates in the fuel NO mechanism increases according to the following sequence of primary fuel nitrogen compounds: ammonia, cyanogen and molecular nitrogen; this last is found to behave like a true fuel nitrogen compound in the early flame stages. Experimental values of the total yield of nitric oxide obtained from the added nitrogen compounds have been determined; they are found to be in good agreement with yields calculated by numerical integration of the empirical overall reaction rates of NO and N2 formation, showing almost the same dependence of the NO yield on temperature, initial fuel nitrogen concentration and oxygen concentration.

Effect of adding ammonia on synthesis of hydrocarbons from carbon monoxide, hydrogen, and ethylene

The addition of small amounts of ammonia to the reaction zone increases the yield of high-molecular hydrocarbons in the synthesis from CO and H2, and also in the hydropolymerization of ethylene, initiated by CO.

Kinetics of nitric oxide formation incombustion processes

Recent investigations of nitric oxide formation in combustion are reviewed with the objectiveof obtaining mechanistic information on nitric oxide formation from atmospheric (molecular) nitrogen and from nitrogen-containing compounds in the fuel. Comparison of existing data on formation of nitric oxide from atmospheric nitrogen with results from detailed kinetics calculations shows that, for the most part, the experimental observations are consistent with a three-reaction mechanism for nitric oxide chemistry if radical concentrations and temperature during combustion are correctly evaluated. The principal nitric oxide formation reactions are O+N2”NO+N, (1) N+O2”NO+O; (2) however, N+OH”NO+H, (3) can be of importance in fuel-rich mixtures. Experimental studies of the formation of nitric oxide from nitrogen-containing compounds indicate that the formation rates are rapid, occurring on a time-scale comparable to that of the combustion reactions. A simplified mechanism for conversion of nitrogen-containing compounds to nitric oxide is proposed. In this mechanism, a partial equilibrium approximation is used to relate the maximum nitric oxide concentration in the combustion zone to the maximum radical concentrations. The proposed mechanism adequately models nitric oxide formation in the shock-induced combustion of lean hydrogen-oxygen mixtures containing small amounts of ammonia.

A nitrogen-balance study using labelled fertilizer in a gas lysimeter

A gas lysimeter study showed negligible losses of gaseous N2 or N2O from rhodes grass plants growing in soil fertilized with either (N15H4)2SO4 or KN15O3; isotope recovered from the soil: plant system averaged respectively 100.5% and 98.9%; neither differed significantly from 100%. Small amounts of ammonia were volatilized into lysimeter atmospheres, averaging 0.6% of that applied as labelled ammonium-N and 0.1% of that as nitrate-N. The importance of these findings is discussed in relation to the conduct of N balance studies.

Control of glutamate dehydrogenase activity during glutamate oxidation in isolated rat-liver mitochondria

1. The kinetics of the reaction of glutamate dehydrogenase with the intramitochondrial nicotinamide nucleotides has been followed in isolated rat-liver mitochondria preincubated with phosphate and phosphate acceptor in order largely to oxidize intramitochondrial nicotinamide nucleotides. In the presence of rotenone and arsenite, the oxidation of glutamate to α-oxoglutarate is accompanied by extensive reduction of NADP + and very little reduction of NAD +, and ceases when NADP is maximally reduced, even though the level of NAD + is still quite high. 2. In mitochondria preincubated in the presence of ATP, oligomycin or rotenone in order largely to reduce intramitochondrial nicotinamide nucleotides, NADPH was oxidized much more rapidly than NADH on the addition of ammonia (α-oxoglutarate was already present). 3. On addition of glutamate to mitochondria preincubated as in 1, a small amount of ammonia is formed and some α-oxoglutarate accumulates in the first few minutes of incubation, during which NADP + is rapidly reduced and NAD + slowly reduced. Aspartate is not formed in the first few seconds. α-Oxoglutarate formation, on the other hand, is greater during the first few seconds than in the subsequent 2 min. 4. When malonate is added together with glutamate, there is a marked deamination of glutamate and only a partial reduction of NADP +. 5. 2-Methyl-1,4-naphthoquinone stimulates the deamination of glutamate markedly both in the absence and presence of malonate, and brings about an oxidation of NADPH. 6. It is concluded that the most important factor controlling the activity of glutamate dehydrogenase during glutamate oxidation in isolated rat-liver mitochondria is the oxidoreduction state of NADP.

CHEMICAL EVENTS ON THE PRIMITIVE EARTH

In this paper the nature of the primitive atmosphere and ocean is considered in the light of geologic and geophysical information. The hypothesis of an early methane-ammonia atmosphere is found to be without solid foundation and indeed is contraindicated. Geologists favor an alternative view-that genesis of air and oceans is a result of planetary outgassing. Some consequences of this view are examined. Volatiles from outgassing interacted with the alkaline crust to form an ocean having a pH 8-9 and tzo produce an atmosphere consisting of CO, C02, N2, and H2. Radiation interacting with such a mixture yields HCN as a principal product. Ultraviolet irradiation of HCN solutions at pH 8-9 yields amino acids and other important substances of biologic interest. The nature of the earth's environment limited the kinds of compounds that might have accumulated in a soup. Arguments concerning feasible components support the view that amino acids and proteins preceded sugars and nucleic acids. If the methane-ammonia hypothesis were correct, there should be geochemical evidence supporting it. What is the evidence for a primitive methane-ammonia atmosphere on earth? The answer is that there is no evidence for it, but much against it. The methane-ammonia hypothesis is in major trouble with respect to the ammonia component, for ammonia on the primitive earth would have quickly disappeared. The effective threshold for degradation by ultraviolet radiation is 2,250 A. A quantity of ammonia equivalent to present atmospheric nitrogen would be destroyed in -30,000 years. Small amounts of ammonia would be reformed, but this process is unimportant in comparison to the destruction. If large amounts of methane had ever been present in the earth's atmosphere, geologic evidence for it should also be available. Laboratory experiments show that one consequence of irradiating a dense, highly reducing atmosphere is the production of hydrophobic organic molecules which are adsorbed by sedimenting clays. The earliest rocks should contain an unusually large proportion of carbon or organic chemicals. This is not the case. The composition of the present atmosphere with respect to the gases neon, argon, krypton, and xenon is crucial. Neon is present on earth to an extent about 10-1O

Radiation-induced Synthesis of Ammonia from Nitrogen and Water

THIS communication reports on the synthesis of small amounts of ammonia by the irradiation of nitrogen and water either with ultra-violet light below 1800 A or with gamma-rays.

Nitrogen Fixation by Transition Metal Complexes

MOST of the known reactions of molecular nitrogen take place under drastic conditions, involving high temperatures and pressures or electrical discharges. Only at room temperatures and atmospheric pressures does nitrogen react appreciably with metallic lithium. It has recently been shown1 that small amounts of ammonia can form on prolonged cathodic reduction of nitrogen (or reduction by stannous chloride) in the presence of aqueous solutions of molybdate and tungstate ions.

Selective hydrogenation of adiponitrile over a cobalt boride catalyst

1. Cobalt boride has a high activity and high selectivity in the hydrogenation of adiponitrile. Under optimal conditions, the hexamethylenediamine yield is 90–94% and that of secondary amines, not more than 5–10%. 2. The catalyst retains its selectivity when small amounts of ammonia (∼6 weight %) are used, when the amount of catalyst is increased to 80% and when the reaction temperature is raised to 125–150°. This indicates that on Co2B reaction (1) strongly predominates over the competing reactions (2) and (3), while reactions (4) and (5) hardly occur.

食品の鮮度測定法に関する研究-XI

The method herein reported employs Amberlite IRC-50 (H-form) for separating histamine (Hm) from interfering substances in a trichloracetic acid extract of sample tissue. Hm which is adsorbed on the ion exchanger at pH 4.6 is eluted with 0.2 N HCl, treated with nitrous acid, and freed from ammonia by vacuum distillation in alkaline reaction. Hm azo pigment which is formed by coupling with p-nitrobenzene diazonium chloride at pH 9 can be extracted with ethylacetate, the extract being dehydrated with anhydrous sodium sulfate. Shortly after a small amount of ammonia being added, the absorbance of the azo pigment solution is to be determined at 550 mμ by a Beckman spectrophotometer or an electrophotometer using a filter of 570 mμ. The recovery of Hm included in several muscle tissue extracts was found 96 to 106%. It was found that the Hm content of mackerel flesh ran parallel with bacterial counts and showed a marked change with quality of the flesh as compared with total volatile bases nitroge.

STREES‐CORROSION CRACKING OF BRASS

Stress‐corrosion cracking has been a problem in the production of wrought‐brass articles for many years. During spinning or deep drawing of brass cups, lamp bases and the like, stresses are set up which remain in the metal unless removed by annealing. Then, if the brass is stored in an atmosphere containing small amounts of ammonia and water vapour, stress‐corrosion cracking may occur. Even very small amounts of ammonia, such as are found in the average home atmosphere, may be sufficient to cause this effect. Industrial atmospheres are likely to be even more corrosive.

On the sources of the nitrogen of vegetation; with special reference to the question whether plants assimilate free or uncombined nitrogen

After referring to the earlier history of the subject, and especially' to the conclusion of Saussure, that plants derive their nitrogen from the nitrogenous compounds of the soil and the small amount of ammonia which he found to exist in the atmosphere, the Authors preface the discussion of their own experiments on the sources of the nitrogen of plants, by a consideration of the most prominent facts established by their own investigations concerning the amount of nitrogen yielded by different crops over a given area of land, and of the relation of these to certain measured, or known sources of it. On growing the same crop year after year on the same land, without any supply of nitrogen by manure, it was found that wheat, over a period of 14 years, had given rather more than 30 lbs.—barley, over a period of 6 years, somewhat less—meadow-hay, over a period of 3 years, nearly 40 lbs.— and beans, over 11 years, rather more than 50 lbs. of nitrogen, per acre, per annum. Clover, another leguminous crop, grown in 3 out of 4 consecutive years, had given an average of 120 lbs. Turnips, over 8 consecutive years, had yielded about 45 lbs.