Quality nitrate

The nitrate (NOp content in crops is one of the most important indicators of farm production quality. Nitrate content in food is strictly regulated because of its toxicity, especially in young children. The actual toxin is not the nitrate ion itself but rather the nitrite ion (NOp, which is formed when nitrate is reduced by intestinal bacteria, notably Escherichia coli. In adults, nitrate is absorbed high in the digestive tract before reduction can take place. In infants, whose stomachs are less acidic, E. coli can colonize higher up the digestive tract and therefore reduce the NOJ to NCp before it is absorbed. 

Minimal effort for upscaling was necessary to perform quality nitrations in a larger laboratory scale or even semi-technical scale. In addition, the limitations of the batch-scale can be avoided. The subsequent hydrolysis is performed in a continuous process as well, thus reducing the oxidative potential and eliminating the necessity for extended stirring times in an acidic environment. 

The first nitration to be reported was that of beri2ene itself. Mitscher-lich in 1834 prepared nitrobenzene by treating benzene with fuming nitric acid. Not long afterwards the important method of effecting nitration with a mixture of nitric and sulphuric acids ( mixed acid ) was introduced, evidently in a patent by Mansfield the poor quality of early nitric acid was probably the reason why the method was developed. Since these beginnings, nitration has been the subject of continuous study. 

Quality of Product. Ammonium nitrate, commonly made from pure synthetic raw materials, is itself of high purity. If the product is intended for use in explosives, it should be at least 99% ammonium nitrate and contain no more than 0.15% water. It should contain only small amounts of water-insoluble and ether-soluble material, sulfates and chlorides, and should not contain nitrites. The soHd product ought to be free from alkalinity, but be only slightly acidic. 

Sandy Soils. The particles in sandy soils are relatively large, with correspondingly large spaces between them. Because these soils are also fairly homogeneous, water moves freely through much of the soil matrix. Any nitrate that is in the soil, whether from fertilizer or from microbial activity, is likely to be carried through the soil slowly but surely with little impediment. A sandy soil above an aquifer is usually seen as a threat to the quality of the water in the aquifer. 

Laboratory Preparation of Absolute Nitric Acid, Strong nitric acid, 99%+, free from oxides (white) is used for many nitrations. Since nitric acid of this quality is not generally commercially available, it is usually prepd in small quantities in the laboratory as needed. The customary procedure is to mix one p of coned nitric acid ( d 1.42g/cc) with 2p of sulfuric acid (d 1.84g/cc) and to distill the nitric acid from this mixt under reduced press, using an all glass system... 

Sulfuric acid 96% (technical quality) and diethyl ether (technical quality) were purchased from Bie Bemtsen A/S, Sandbaekvej 7, DK-2610 Roedovre, Denmark and used without further purification. Isoquinoline (97%) and potassium nitrate (99%) were purchased from Aldrich Chemical Company, Inc. and used without further purification. 

The most recent comprehensive assessment of the quality of rivers in the USA is that of Smith et al. 12), This followed an earlier assessment by Wolman et al. in 1971 (iS). The former 1987 assessment was based on 24 water quality measures from 161-383 stations around the country covering the period 1974-1981. Trends observed included major increases in nitrate, phosphorous, sodium, suspended sediment, fecal bacteria, dissolved oxygen deficit, arsenic and selenium. Major decreases were observed with nitrate, suspended sediment, fecal bacteria, dissolved oxygen deficit and lead. 

Lead and Alloys Chemical leads of 99.9 percent purity are used primarily in the chemical industry in environments that form thin, insoluble, and self-repairable protective films, e.g., salts such as sulfates, carbonates, or phosphates. More soluble films such as nitrates, acetates, or chlorides offer little protection. Alloys of antimony, tin, and arsenic offer limited improvement in mechanical properties, but the usefulness of lead is limited primarily because of its poor structural qualities. It has a low melting point and tensile stress as low as 1 MPa (145 Ibf/in ). 

Since many ion exchange columns exhibit mixed-mode interactions with analytes, factor analysis has been found to be useful in optimization.84 A 3-year, comprehensive review of inter-laboratory errors in determinations of the anions chloride, nitrate, and sulfate and the cations sodium, potassium, magnesium, and calcium suggested that multipoint calibration is essential and nonlinear calibration desirable.102 The need for nonlinear calibration was confirmed by an extended quality assurance study of chloride, sulfate, and nitrate in rainwater.103... 

The most obvious advantages are the reduction in effluents and the improved working atmosphere. The safety aspects have also been improved to a very large extent and the quality of the product in many cases is superior to that produced by the older methods. All forms of heat treatment are amenable to fluidized bed techniques, but austempering is the most cost effective, in spite of the nitrate bath method being less troublesome than other traditional methods. 

Chung, S., Gassman, P.W., Huggins, D.R., and Randall, G.W., EPIC tile flow and nitrate loss predictions for three Minnesota cropping systems, Journal of Environmental Quality, 30, 822-830, 2001. 

Control of exudation depends mainly on the suitable choice of the nitrocellulose used. Some lack of uniformity in this product is certainly desirable. This offers no serious difficulty, although it is necessary to ensure a constant watch on manufacturing processes to see that quality is maintained. In other gelatine explosives, particularly those containing ammonium nitrate, exudation can be induced by slow chemical reaction. The addition of alkalis, for example, can liberate ammonia which in turn can react with nitrocellulose and cause it to lose its power of binding nitroglycerine. Such effects are accelerated at high temperatures and under wet conditions and it is usual practice to test all explosives under such adverse conditions before they are put on the market. 

Use of a screw feeder to charge a reactor with the 2-anisidine salt led to ignition of the latter. It was known that the salt would decompose exothermically above 140°C, but later investigation showed that lower-quality material could develop an exotherm above 46°C under certain conditions [1]. Fast flame propagation occurs on moderately heating anisidine nitrate powder [2],... 

As follows from the results obtained, numerous parameters influence the quality of precipitates, vs raw materials used (such as, manganese sulphate, nitrate, chloride) pH of initial and final solutions the excess of the oxidant the type of a neutralizing agent (lithium, sodium, potassium hydroxide) the washing method, and pH of leachates. More detailed description of the synthetic routine will be published elsewhere. 

Extensive research has been conducted into the atmospheric chemistry of organic chemicals because of air quality concerns. Recently, Atkinson and coworkers (1984, 1985, 1987, 1988, 1989, 1990, 1991), Altshuller (1980, 1991) and Sabljic and Glisten (1990) have reviewed the photochemistry of many organic chemicals of environmental interest for their gas phase reactions with hydroxyl radicals (OH), ozone (03) and nitrate radicals (N03) and have provided detailed information on reaction rate constants and experimental conditions, which allowed the estimation of atmospheric lifetimes. Klopffer (1991) has estimated the atmospheric lifetimes for the reaction with OH radicals to range from 1 hour to 130 years, based on these reaction rate constants and an assumed constant concentration of OH... 

Causape J, Quilez D, Aragues R (2004) Assessment of irrigation and environmental quality at the hydrological basin level - II. Salt and nitrate loads in irrigation return flows. Agric Water Manage 70 211-228... 

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