Nitration method

The precipitated acetyHde must be decomposed with hydrochloric acid after the titration as a safety measure. Concentrated solutions of silver nitrate or silver perchlorate form soluble complexes of silver acetyHde (89). Ammonia and hydrogen sulfide interfere with the silver nitrate method which is less... 

J. H. Ridd, Acc. Chem. Res. 4 248 (1971) J. H. Ridd, in Studies on Chemical Structure and Reactivity, J. H. Ridd, ed., John Wiley Sons, New Vbik, 1966, Chapter 7 J. G. Hoggett, R. B. Moodie, J. R. Penton, and K. Schofield, Nitration and Aromatic Reactivity, Cambridge University Press, Cambridge, 1971 K. Schofield, Aromatic Nitration, Cambridge University Press, Cambridge, 1980 G. A. Olah, R. Malhotra, and S. C. Narang, Nitration, Methods and Mechanisms, VCH Publishers, New i)rk, 1989. 

The most common indirect nitration method, often used in nitrating phenols, consists of sul-forating the compd and then replacing the sulfo group by a nitro group. The usual nitrating agent for these reactions is coned nitric acid... 

Other indirect nitration methods applied on an industrial scale for nitrating phenols involve introducing a nitroso group into the phenol and then oxidizing it to the nitro group. Another method involves the oxidation of a primary amino group to the nitro group... 

Entry 5 is an example of nitration in acetic anhydride. An interesting aspect of this reaction is its high selectivity for the ortho position. Entry 6 is an example of the use of trifluoroacetic anhydride. Entry 7 illustrates the use of a zeolite catalyst with improved para selectivity. With mixed sulfuric and nitric acids, this reaction gives a 1.8 1 para ortho ratio. Entry 8 involves nitration using a lanthanide catalyst, whereas Entry 9 illustrates catalysis by Sc(03SCF3)3. Entry 10 shows nitration done directly with N02+BF4, and Entry 11 is also a transfer nitration. Entry 12 is an example of the use of the N02—03 nitration method. 

To establish the well drainage boundaries and fluid flow patterns within the TFSA-waterflood pilot, an interwell chemical tracer study was conducted. Sodium thiocyanate was selected as the tracer on the basis of its low adsorption characteristics on reservoir rocks (36-38), its low and constant background concentration (0.9 mg/kg) in produced fluids and its ease and accuracy of analysis(39). On July 8, 1986, 500 lb (227 kg) of sodium thiocyanate dissolved in 500 gal (1.89 m3> of injection brine (76700 mg/kg of thiocyanate ion) were injected into Well TU-120. For the next five months, samples of produced fluids were obtained three times per week from each production well. The thiocyanate concentration in the produced brine samples were analyzed in duplicate by the standard ferric nitrate method(39) and in all cases, the precision of the thiocyanate determinations were within 0.3 mg/kg. The concentration of the ion in the produced brine returned to background levels when the sampling and analysis was concluded. 

Nitration with dinitrogen pentoxide (N205) has increased in its importance as an environmentally cleaner alternative to conventional procedures. It might become the nitration method of the future. Dinitrogen pentoxide can be produced either by ozone oxidation of dinitrogen tetraoxide (N204) or electrolysis of N204 dissolved in nitric acid.19... 

The nitration of active methylene compounds generally proceeds via the reaction of carbanionic intermediates with an electrophilic nitrating agent such as alkyl nitrate (alkyl nitrate nitration). Details of this process are well documented in the reviews.38 The alkyl nitrate nitration method has been used extensively for the preparation of arylnitromethanes. The toluene derivatives, which have electron-withdrawing groups are nitrated with alkyl nitrates in the presence of KNH2 in liquid ammonia (Eqs. 2.19 and 2.20).39... 

Determination in Biological Fluids and Tissues All the advances in pharmacokinetics and drug metabolism described in Sections 7 and 8 would not have been possible without the availability of the proper analytical methods. The following is a tabulation of publications in this field, most of which have already been discussed in Section 5. It should be mentioned that a few publications talk about aspirin blood levels, but really mean salicylate levels. The following tabulation covers only those papers where aspirin was differentiated from other salicylates by chromatography or other means. It seems that the "workhorse" for serum salicylate levels is still the colorimetric (ferric-nitrate) method of Brodie, Udenfriend and Coburn153 published in 1944, or modifications thereof. Simplified versions (cf. 206) may lead to erroneous results under certain conditions.207 The method is also applicable for urinary metabolites after proper hydrolysis (cf. 208). For other methods restricted to salicylic acid, see Section 5.61. 

Olah, G.A. Malhotra, R. und Narang, S.C. Nitration, Methods and Mechanisms, VCH-Verlagsges., Weinheim 1989 Nitro Compounds, Recent Advances in Synthesis and Chemistry, Hrsg. Feuer, H. und Nielsen, A. 77, VCH-Verlagsges., Weinheim 1990 Chemistry of Energetic Materials, Hrsg. Olah, G.A. und Squire, D.R., Academic Press, London 1991... 

Bulk physical property tests, such as density and heating value, as well as some compositional tests, such as the Orsat analysis and the mercuric nitrate method for the determination of unsaturation, are still used. However, the choice of a particular test is dictated by (1) the requirements of the legislation, (2) the properties of the gas under study, and (3) the selection by the analyst of a suitable suite of tests to meet the various requirements. For example, judgment by the analyst is necessary whether or not a test that is applied to liquefied petroleum gas is suitable for process gas or natural gas insofar as inference from the nonhydrocarbon constituents will be minimal. 

Olah, G.A. Malhotra, R. Narang, S.C. (1989) Nitration Methods and Mechanisms, VCH Publishers, New York. 

G. A. Olah, R. Malhotra and S. C. Narang, Nitration Methods and Mechanisms, Wiley-VCH, Weinheim (1989). 

The nitration method is also adaptable to the preparation of ethyl m-nitrobenzoate. The yield is, however, slightly lower, owing to the greater solubility of the ethyl ester. 

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