Ferric perchlorate method

Distillation ofhydrazoic acid from strong acid solutions is the most common method of separation [12, 17], For small quantities of azide ion in relatively large volumes of solvent, evaporation in alkaline media or carrier precipitation is necessary for the preliminary concentration of azide ions prior to distillation. The distillations are usually made from perchloric acid solutions. A 50-ml round-bottom flask, with a side-arm attached (so that a stream of inert gas passes through the solution) and an air condenser is preferable for distilling hydrazoic acid. The addition of a diluent carrier gas provides added safety. Absorbing solutions for the hydrazoic acid include known, excess quantities of ceric ion. standard base, or a known quantity of ferric perchlorate for colorimetric determination of small quantities of azide ion. The distillation separation is complex and lengthy, but the method is reliable and has universal applicability. 

Imanari et al. has reported a spectrophotometric detection of many inorganic anions using a post-column reactor [42]. A stream of ferric perchlorate, which is essentially colorless, is mixed with the column effluent. The ferric perchlorate is colorless because perchlorate is a poor complexing anion, but most anions will complex the iron and form colored species that can be detected at 330-340 nm (Table 4.3). A similar detection method works for ions such as orthophosphate, pyrophosphate, nitrilo-triacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA) [46]. 

Wieland, 1907 Wieland and Wecker, 1910). Oxidation was carried out in an inert solvent such as benzene, from which the salt precipitated. The easier and more reliable preparation of perchlorate salts by the iodine-silver perchlorate method (Weitz and Schwechten, 1926, 1927), to which we have referred earlier (p. 168), allowed a much clearer understanding of the nature of triarylaminium ions to be obtained. Isolation of perchlorates permitted chemical studies, and easy reduction to the triarylamine by iodide ion, ferrous ion, etc., was consistent with the cation-radical view that was developed. The name aminium ion was coined by Weitz. Other salts were prepared such as tritolylaminium picrate (by oxidation of the amine with lead dioxide in the presence of picric acid), and it was also recognized that conjugate anions in salts obtained by oxidation with antimony pentachloride, phosphorus pentachloride and ferric chloride had to be complex anions rather than simple anionic radicals. This is a particularly pertinent point in antimony pentachloride oxidations (p. 165). 

The determination of formation constants may involve the photometric measurement of the complex formed in the presence of a large excess of one of the reagents, so that the formation of the complex may be considered to be essentially complete this is known as the method of mixtures of nonequimolar solutions. This method is based on Job s general equation [27, 28] for systems involving mixtures. The method has been applied to the determination of the dissociation constant of Fe(III)-sulfo-salicyclic acid mixtures in a pH 5.3 buffer, using sulfosalicyclic acid solutions 3, 5, and 8 times as concentrated as the ferric perchlorate. The best results were obtained by assuming that a 1 1 complex is formed, and was calculated to be 2 x 10" . 

A new method of preparation of electrically conductive PT and PAT (e.g. n = 1, PMT) is the direct oxidation of thiophene or 3-alkylthiophene in the presence of a small amount of bithiophene with ferric perchlorate. The obtained PMT has higher electrical conductivity (about 30 S cm ) than those prepared by the conventional method of polycondensation of 2,5-dihalo-3-methyl-thiophene [576]. A simultaneous polymerization and doping of bithiophene and terthiophene can be carried out with thallium(III) trifluoroacetate in trifluoro-acetic acid [577]. 

It might be well to point out that after the initial paper (Shaabani et al. 2008), very simple, efficient, clean, and practical methods for the synthesis of highly substituted quinoxalin-2-amine derivatives in good yields have been reported. They proceed in the presence of HCl (33-54 %) (Krasavin and Parchinsky 2008 Krasavin et al. 2009), ferric perchlorate (91-93 %) (Heravi et al. 2009), cerium(IV) ammonium nitrate (CAN) (71-96 %) (Li et al. 2009a), and ethylenediaminete-traacetic acid (72-95 %) (KoUa and Lee 2010) as efficient catalysts correspondingly in MeOH, MeCN, EtOH, or H2O. 

However, this method is appHed only when esterification cannot be effected by the usual acid—alcohol reaction because of the higher cost of the anhydrides. The production of cellulose acetate (see Fibers, cellulose esters), phenyl acetate (used in acetaminophen production), and aspirin (acetylsahcyhc acid) (see Salicylic acid) are examples of the large-scale use of acetic anhydride. The speed of acylation is greatiy increased by the use of catalysts (68) such as sulfuric acid, perchloric acid, trifluoroacetic acid, phosphoms pentoxide, 2inc chloride, ferric chloride, sodium acetate, and tertiary amines, eg, 4-dimethylaminopyridine. 

Besides acetophenone, this reaction was also applied to p-chloro- andp-methoxyacetophenone, and even to an aliphatic ketone, acetone (although the yield was stated to be only half as large as that obtained from mesityl oxide, i.e., less than 30%, Dorofeenko and co-workers reported a 45% yield of 2,4,6-trimethylpyrylium perchlorate from acetone, acetic anhydride, and perchloric acid), and is the standard method for preparing pyrylium salts with identical substituents in positions 2 and 4. The acylating agent may be an anhydride in the presence of anhydrous or hydrated ferric chloride, or of boron fluoride, or the acid chloride with ferric chloride.Schneider and co-workers ... 

Silverman and Dodson made the first detailed isotopic study of this exchange system using the separation afforded by the addition of 2,2 -dipyridyl at pH 5, followed by the precipitation of the ferric iron with either ammonia or 8-hydro-xyquinoline. Dodson , using this separation method, had previously obtained an overall rate coefficient of 16 l.mole" sec at 23 °C for 0.4 M perchloric acid media. The exchange in perchlorate and perchlorate-chloride media was found to conform to a rate law, first order with respect to both total ferrous and ferric ion concentrations, with an observed rate constant (k bs) dependent on the hydrogen-ion concentration, viz. 

The phase-stabilized AN is prepd by mixing 90 parts AN, 10 ps K nitrate some water, heating the mixt to 140°F, drying and grinding to 40 micron size particles. The proplnt is compressed into grains. Example of compn AN 82.95, K nitrate 9.22, petroleum pitch 4.11 90/10 copolymer of l,3-butadiene/2-methyl-5 -vinyl pyridine 1.76 Amm dichromate 1.96%] EE)R.MacDonald A.M.Bedard, "Methods of Chemical Analysis of Cardeplex Propellant No 4760/A5 and Its Ingredients", CARDE TR426/63 (1963) (Cardeplex No 4760/A5 is a composite ammonium perchlorate-polyurethane proplnt. Analysis of fully cured product includes detns of Amm perchlorate, Al, ferric acetylacetonate, phenyl-/3 -naphthylamine, lithium fluoride total iron) FF)Anon,... 

Reagent. Mix together 5 ml of ferric chloride solution, 45 ml of a 20% w/w solution of perchloric acid, and 50 ml of a 50% v/v solution of nitric acid. Method. Dissolve the sample in a minimum volume of 2M hydrochloric acid and add an equal volume of the reagent. 

Chloride ions react with undissociated mercuric thiocyanate to form undissociated mercuric chloride and free thiocyanate ions. The thiocyanate ions react with ferric ion (Fe " ") to form the highly colored, reddish complex of ferric thiocyanate with an absorption peak at 480 nm. Perchloric acid increases the intensity of the red color. High concentrations of globulins in the serum interfere in these methods because turbidity develops. This reaction is also very temperature sensitive. 

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