Nitrates, for preparation

Ammonium perrhenate, mixture of, with ammonium nitrate for preparation of rhenium, 1 177, 178... 

Strontium nitrate, for preparation of strontium sulfate or strontium selenite, 3 17 Strontium selenide, 3 20 phosphors, 3 11, 22 Strontium selenite, for preparation of strontium selenide, 3 20 Strontium sulfate, for preparation of strontium sulfide, 3 19 Strontium sulfide, 3 20 phosphors, 3 11, 21, 23 Structure, of 1,3-diketones, 2 10 electronic, of rare earth elements, 2 30... 

Do not heat the silver solution or allow it to stand even for a few hours, since explosive silver fulminate may be formed. The ammoniacal solution of silver nitrate is prepared by treating 3 ml. of 0-lN silver nitrate solution with very dilute ammonia solution dropwise until the precipitate which is first formed just redissolves. 

Despite the fact that solutions of acetyl nitrate prepared from purified nitric acid contained no detectable nitrous acid, the sensitivity of the rates of nitration of very reactive compounds to nitrous acid demonstrated in this work is so great that concentrations of nitrous acid below the detectable level could produce considerable catalytic effects. However, because the concentration of nitrous acid in these solutions is unknown the possibility cannot absolutely be excluded that the special mechanism is nitration by a relatively unreactive electrophile. Whatever the nature of the supervenient reaction, it is clear that there is at least a dichotomy in the mechanism of nitration for very reactive compounds, and that, unless the contributions of the separate mechanisms can be distinguished, quantitative comparisons of reactivity are meaningless. 

The manufacture of silver nitrate for the preparation of photographic emulsions requires silver of very high purity. At the Eastman Kodak Company, the principal U.S. producer of silver nitrate, 99.95% pure silver bars are dissolved in 67% nitric acid in three tanks coimected in parallel. Excess nitric acid is removed from the resulting solution, which contains 60—65% silver nitrate, and the solution is filtered. This solution is evaporated until its silver nitrate concentration is 84%. It is then cooled to prepare the first crop of crystals. The mother Hquor is purified by the addition of silver oxide and returned to the initial stages of the process. The cmde silver nitrate is centrifuged and recrystallized from hot, demineralized water. Equipment used in this process is made of ANSI 310 stainless steel (16). 

Anthraquinone dyes are derived from several key compounds called dye intermediates, and the methods for preparing these key intermediates can be divided into two types (/) introduction of substituent(s) onto the anthraquinone nucleus, and (2) synthesis of an anthraquinone nucleus having the desired substituents, starting from benzene or naphthalene derivatives (nucleus synthesis). The principal reactions ate nitration and sulfonation, which are very important ia preparing a-substituted anthraquiaones by electrophilic substitution. Nucleus synthesis is important for the production of P-substituted anthraquiaones such as 2-methylanthraquiQone and 2-chloroanthraquiaone. Friedel-Crafts acylation usiag aluminum chloride is appHed for this purpose. Synthesis of quinizatia (1,4-dihydroxyanthraquiQone) is also important. 

N2O4 has been extensively studied as a nonaqueous solvent system and it is uniquely useful for preparing anhydrous metal nitrates and nitrato complexes (p. 468). Much of the chemistry can be rationalized in terms of a selfionization equilibrium similar to that observed for... 

Reagents. Supporting electrolyte. For chloride and bromide, use 0.5 M perchloric acid. For iodide, use 0.1M perchloric acid plus 0.4M potassium nitrate. It is recommended that a stock solution of about five times the above concentrations be prepared (2.5M perchloric acid for chloride and bromide 0.5M perchloric acid + 2.0A f potassium nitrate for iodide), and dilution to be effected in the cell according to the volume of test solution used. The reagents must be chloride-free. 

An interesting extension of the above experiment is the titration of a mixture of halides (chloride/iodide) with silver nitrate solution. Prepare a solution (100 mL) containing both potassium chloride and potassium iodide weigh each substance accurately and arrange for the solution to be about 0.025 M with respect to each salt. A silver nitrate solution of known concentration (about 0.05 M) will also be required. 

Reagents. In view of the sensitivity of the method, the reagents employed for preparing the ground solutions must be very pure, and the water used should be re-distilled in an all-glass, or better, an all-silica apparatus the traces of organic material sometimes encountered in demineralised water (Section 3.17) make such water unsuitable for this technique unless it is distilled. The common supporting electrolytes include potassium chloride, sodium acetate-acetic acid buffer solutions, ammonia-ammonium chloride buffer solutions, hydrochloric acid and potassium nitrate. 

A three-step nitration process of toluene is described. The advantages of the modified process are reduced waste, less hazardous operation, reduced oleum requirement, partial replacement of coned HN03 with dil HN03, and higher rate of toluene flow into the reactor (Ref 86) The continuous process of H.C. Prime (Ref 73) for preparing TNT was studied by thin-layer chromatography on silica gel with a starch binder and a fluorescent indicator. The nitration... 

The usual preparative methods employ mixed acids. The N content of the NS depends on the composition of the mixed acid and on the mixed acid-to-starch ratio. This is illustrated in the triangular diagram of Fig 1 obtained by Hackel and Urbanski (Ref 12). Starch was nitrated for one hour and 50 mins at 10—12°. The acid compn is given in mole %. The region of mixts between the curve AAA Af and the HNO3—... 

A further observation is the fact that differences in rates of nitration between the reagents prepared at different temperatures tended to zero as the water concentration of the added nitric acid was decreased to zero73. It has been argued that, since the acid-catalysed hydrolysis of acetic anhydride must be very rapid at 25 °C and removes water which initially competes with acetic anhydride and acetyl nitrate for protons, this removal permits equilibria (30) and (31) to be displaced towards products. The more anhydrous the nitric acid, the less important is this initial hydrolysis of the acetic anhydride and so the difference in the nitrating power of the differently prepared mixtures becomes less. When reagents are mixed at low temperatures, the hydrolysis of the anhydride is very slow, but once this is accomplished, formation of the protonated acetyl nitrate and subsequent nitration is rapid as observed73. 

We wish to thank Dr. G. H. Cady for lending us his apparatus, Professor Don M. Yost and Mr. A. Beerbower for preparing the fluorine nitrate used in this work, Mr. K. S. Palmer for assisting in the preparation of the electron diffraction photographs, and Dr. Sidney Weinbaum and Mrs. M. Lassettre for assisting in their interpretation. 

P-Nitronaphthalene is not formed by direct nitration. For the preparation of p-naphthylamine, the Bucherer reaction may be applied to p-naphthol, i.e., by heating with ammoniacal ammonium sulphite solution at 150° (under pressure). The reaction involves the addition of the bisulphite to the keto form of p-naphthol ... 

A literature method for preparation of chromyl acetate by interaction of chromium trioxide and acetic anhydride was modified by omission of cooling and agitation. The warm mixture exploded violently when moved [1], A later publication emphasised the need for cooling, and summarised several such previous occurrences [2], An earlier reference attributes the cause of chromium trioxide-acetic anhydride oxidation mixtures going out of control to presence of nitric acid or nitrates in the chromium trioxide, and a simple test to check this point is given [3], Mixtures used as a reagent for the remote oxidation of carboxylic esters are potentially explosive, and must be made up and used at below 25 °C under controlled conditions [4], An attempt to purify the anhydride by warming with 2% w/v of trioxide led to an explosion at 30°C [5],... 

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