Crystalline anhydrous oxides

The products of equation 11 are separated by controlled crystallizations to produce high purity crystalline anhydrous ammonium perchlorate and sodium chloride. The main use for ammonium perchlorate is as an oxidizer in the propellant of rockets and missiles (see Explosives and propellants). 

A solution of 21.3 g. (0.10 mole) of freshly distilled N,N-dimethyldodecylamine (Note 1), 9.6 g (0.10 mole) of 94% <-butyl hydroperoxide (Note 2), and 0.050 g. of vanadium oxyacetylacetonate (Note 3) in 27 g. (34 ml.) of Cbutyl alcohol is placed in a 250-ml. round-bottomed flask fitted with a. thermometer, a reflux condenser, and a heating mantle. The reaction mixture is heated to approximately 65-70°, at which point an exothermic reaction begins. The heating is discontinued until the vigorous exothermic reaction subsides (about 5 minutes) and then the reaction mixture is heated at reflux (the reaction mixture boils at 90°) for 25 minutes. After the resulting mixture has been cooled to room temperature, it is analyzed (Note 4) to establish the absence oft-butyl hydroperoxide, and then concentrated with a rotary evaporator (30-35° bath with 30-40 mm. pressure). The crude solid residue is triturated with 50 ml. of cold (0-5°), anhydrous diethyl ether and then filtered under conditions which prevent exposure of the residual amine oxide to atmospheric moisture (Note 5). The residual solid is washed with 50 ml. of cold (0-5°) anhydrous diethyl ether and then dried under reduced pressure to leave 12.9-15.5 g. of the crystalline amine oxide, m.p. 131-131.5°. Concentration of the mother liquors and trituration of the residual paste with 25 ml. of cold (0-5°) anhydrous diethyl ether separates another 4.9-3.4 g. of the amine oxide, m.]). 130-131°. The total yield of the crystalline amine oxide (Note 6) is 17.4-18.9 g. (76 83%). 

After calcination of the activated samples at 400-1100°C for 24 h, only monophase crystalline calcium ferrite phase was observed. Ssp=1 3 m /g. Note, that without mechanical activation anhydrous oxides do not react completely even at 1000°C, giving a mixture of Ca Fe20s and CaFe204, while monophase Ca2pe205 is formed only after calcination at 1100°Cforl00h. 

Thus, the final result of mechanical activation of anhydrous oxides mixtures is determined by the correlation between the processes of formation of crystalline Ca2Fe20s and its amorphization. 

Several methods have been proposed in order to check the sealing of a MAS rotor. It has been suggested that the intrusion of moisture into the MAS rotor can be checked by trimethylphosphine oxide, which is highly hygroscopic. Its hydrated form is separately observed in MAS NMR spectra from the crystalline (anhydrous) form. Gas leakage from the MAS rotor can be monitored by measuring Xe MAS NMR spectra of xenon confined in zeolites, as well as He MAS NMR spectra of He gas. 

Required Arsenious oxide, 27 g. aniline, 20 ml. (20 g.) anhydrous sodium carbonate, 55 g. crystalline copper sulphate,... 

Silver difluoride [7783-95-1], AgF2, is a black crystalline powder. It has been classified as a hard fluorinating agent (3) which Hberates iodine from KI solutions and o2one from dilute aqueous acid solutions on heating. It spontaneously oxidizes xenon gas to Xe(II) in anhydrous hydrogen fluoride solutions (20). 

Tripotassium hexakiscyanoferrate [13746-66-2] K2[Fe(CN)g], forms anhydrous red crystals. The crystalline material is dimorphic both orthorhombic and monoclinic forms are known. The compound is obtained by chemical or electrolytic oxidation of hexacyanoferrate(4—). K2[Fe(CN)g] is soluble in water and acetone, but insoluble in alcohol. It is used in the manufacture of pigments, photographic papers, leather (qv), and textiles and is used as a catalyst in oxidation and polymerisation reactions. 

Lead borate moaohydrate [14720-53-7] (lead metaborate), Pb(B02)2 H20, mol wt 310.82, d = 5.6g/cm (anhydrous) is a white crystalline powder. The metaborate loses water of crystallization at 160°C and melts at 500°C. It is iasoluble ia water and alkaHes, but readily soluble ia nitric and hot acetic acid. Lead metaborate may be produced by a fusion of boric acid with lead carbonate or litharge. It also may be formed as a precipitate when a concentrated solution of lead nitrate is mixed with an excess of borax. The oxides of lead and boron are miscible and form clear lead-borate glasses in the range of 21 to 73 mol % PbO. 

A solution of estradiol (38, 15 mg) in methanol-OD (4 ml) and one drop of 10% deuteriosulfuric acid in deuterium oxide is heated under reflux for 5 days. After cooling the reaction mixture is diluted with ether, washed with dilute sodium bicarbonate solution and water, then dried over anhydrous sodium sulfate. Evaporation of the ether gives crystalline 2,4-d2-estradiol (39, 15 mg, 99%), mp 173-175° (ether-hexane), exhibiting 82% isotopic purity and only one aromatic hydrogen by NMR. (For an experimental procedure describing the exchange of aromatic protons under Clemmensen conditions, see section III-D.)... 

A 500-ml rcund-bottom flask is equipped with a reflux condenser, a gas inlet tube, and a gas outlet leading to a bubbler. The flask is charged with a solution of rhodium (III) chloride trihydrate (2 g) in 70 ml of 95 % ethanol. A solution of triphenylphosphine (12 g, freshly recrystallized from ethanol to remove the oxide) in 350 ml of hot ethanol is added to the flask, and the system is flushed with nitrogen. The mixture is refluxed for 2 hours, following which the hot solution is filtered by suction to obtain the product. The crystalline residue is washed with several small portions of anhydrous ether (50 ml total) affording the deep red crystalline product in about 85% yield. 

A mixture containing 186 g (0.20 mol) of 2-aminopyridine, 0.55 g of lithium amide and 75 cc of anhydrous toluene was refluxed for 1.5 hours. Styrene oxide (12.0 g = 0.10 mol) was then added to the reaction mixture with stirring over a period of ten minutes. The reaction mixture was stirred and refluxed for an additional 3.5 hours. A crystalline precipitate was formed during the reaction which was removed by filtration, MP 170°C to 171°C, 1.5 g. The filtrate was concentrated to dryness and a dark residue remained which was crystallized from anhydrous ether yield 6.0 g. Upon recrystallization of the crude solid from 30 cc of isopropyl alcohol, 2.0 g of a light yellow solid was isolated MP 170°C to 171°C. 

There have been many instances of examination of the effect of additive product on the initiation of nucleation and growth processes. In early work on the dehydration of crystalline hydrates, reaction was initiated on all surfaces by rubbing with the anhydrous material [400]. An interesting application of the opposite effect was used by Franklin and Flanagan [62] to inhibit reaction at selected crystal faces of uranyl nitrate hexa-hydrate by coating with an impermeable material. In other reactions, the product does not so readily interact with reactant surfaces, e.g. nickel metal (having oxidized boundaries) does not detectably catalyze the decomposition of nickel formate [222],... 

Rhodium(III) chloride trihydrate (2 g.) is dissolved in 70 ml. of ethanol (95%) in a 500-ml. round-bottomed flask fitted with gas inlet tube, reflux condenser, and gas exit bubbler. A solution of 12 g. of triphenylphosphine (freshly crystallized from ethanol to remove triphenylphosphine oxide) in 350 ml. of hot ethanol is added and the flask purged with nitrogen. The solution is refluxed for about 2 hours, and the crystalline product which forms is collected from the hot solution on a Buchner funnel or sintered-glass filter. The product is washed with small portions of 50 ml. of anhydrous ether yield 6.25 g. (88% based on Rh). This crystalline product is deep red in color. 

The BFT, PFg" and SbCl salts of cation radicals are readily prepared by oxidation of organic donors with the corresponding NO+ salts in a relatively nonpolar solvent such as dichloromethane. For example, a solution of the hydroquinone ether MA in anhydrous (deaerated) dichloromethane turns purple upon the addition of crystalline NO+BFT at low temperature ( 50°C).173 The coloration is due to formation of the donor/acceptor complex [MA, NO+] (equation 34). 

The strongly oxidizing SbCl5 is an effective oxidant for the preparation of cation-radical salts of hexachloroantimonate (SbCl ) from a variety of organic donors, such as para-substituted triarylamines, fully-substituted hydroquinone ethers, tetraarylethylenes, etc.176 For example, the treatment of the hydroquinone ether EA (2 mmol) with SbCl5 (3 mmol) in anhydrous dichloromethane at — 78°C immediately results in an orange-red solution from which the crystalline cation radical salt readily precipitates in quantitative yield upon the slow addition of anhydrous diethyl ether (or hexane)173 (equation 36). 

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