Evaporation, deposition mixtures

Aqueous nitric acid up to 50 per cent, concentration has little action on arsenic,9 but the concentrated acid or aqua regia causes rapid oxidation to arsenious and arsenic acids. When the acid is more dilute some ammonia may be formed.10 A mixture of arsenic and potassium nitrate detonates on ignition.11 Solutions of ammonium12 and barium13 nitrates slowly dissolve arsenic to form arsenite and arsenate. Hydra-zoic acid dissolves the element with evolution of hydrogen, and the solution on evaporation deposits arsenious oxide.14 Nitrosyl chloride15 and potassium amide16 also react with arsenic. 

Many other methods of preparation have been employed. For example, the triiodide is formed when arsenious oxide,5 or a mixture of this oxide with sulphur,6 is heated in iodine vapour or when arsenious oxide is heated with iodine,7 hydriodic acid,8 a mixture of potassium iodide and acetic acid,9 or a mixture of potassium iodide and potassium hydrogen sulphate.10 When arsenic disulphide and iodine, in the proportions 1 As Ss 3la, are heated together, arsenic triiodide is formed.11 When arsenic trisulphide is fused with an excess of iodine, the product is soluble in carbon disulphide and the solution on evaporation deposits arsenic triiodide, then a sulphiodide and finally sulphur with excess of sulphide the product is the sulphiodide, AsS2I. If a solution of iodine in carbon disulphide is added to arsenic di- or tri-sulphide, the triiodide and sulphur are formed. The triiodide is also produced when a mixture of the trisulphide and mercuric iodide is heated 12. when hydriodic... 

The molten mixture of iodo-acid and silver is maintained at 100°—120° until it thickens and the temperature is then raised to 150°—160°. After remaining at this temperature for two or three hours the mixture is cooled and then extracted with boiling water, The aqueous extract, on evaporation, deposits a considerable crust of adipic acid which is separated. A further quantity of adipic acid is obtained by evaporating the mother-liquor, and the whole may be recrystallised from hot water. Colourless crystals m.p, 148°-149°,... 

Cobalt Metaphosphate, Co(P03)2, is obtained9 by evaporating a mixture of cobalt sulphate and phosphoric acid in a platinum dish, and subsequently heating to 300° C. It is deposited as a beautiful, rose-coloured, anhydrous compound, insoluble in water and dilute acids, but soluble in concentrated sulphuric acid. 

At present, metallization of dielectrics and semiconductors is carried out either by means of high-temperature, long fusing of metal-containing pastes, or by means of sputtering, condensation at vacuum-thermal evaporation, deposition from vapor-gas mixtures, electroless metallization with preliminary activation by the salts of noble metals, etc. (1-32). 

Deposit mixture on matrix and allow water to evaporate... 

Carbon disulphide should never be used if any alternative solvent is available, as it has a dangerously low flash-point, and its vapours form exceedingly explosive mixtures with air. Ether as a solvent for recrystallisation is much safer than carbon disulphide, but again should be avoided whenever possible, partly on account of the danger of fires, and partly because the filtered solution tends to creep up the walls of the containing vessel and there deposit solid matter by complete evaporation instead of preferential crystallisation. 

Mix 6 2 ml. (6 4 g.) of pure ethyl acetoacetate and 5 ml. of pure phenylhydrazine in an evaporating-basin of about 75 ml. capacity, add 0 5 ml. of acetic acid and then heat the mixture on a briskly boiling water-bath (preferably in a fume-cupboard) for I hour, occasionally stirring the mixture with a short glass rod. Then allow the heavy yellow syrup to cool somewhat, add 30-40 ml. of ether, and stir the mixture vigorously the syrup may now dissolve and the solution shortly afterwards deposit the crystalline pyrazolone, or at lower temperatures the syrup may solidify directly. Note. If the laboratory has been inoculated by previous preparations, the syrup may solidify whilst still on the water-bath in this case the solid product when cold must be chipped out of the basin, and ground in a mortar with the ether.) Now filter the product at the pump, and wash the solid material thoroughly with ether. Recrystallise the product from a small quantity of a mixture of equal volumes of water and ethanol. The methyl-phenyl-pyrazolone is obtained... 

A mixture of 0.30 mol of the tertiairy acetylenic alcohol, 0.35 mol of acetyl chloride (freshly distilled) and 0.35 mol of /V/V-diethylaniline was gradually heated with manual swirling. At 40-50°C an exothermic reaction started and the temperature rose in a few minutes to 120°C. It was kept at that level by occasional cooling. After the exothermic reaction had subsided, the mixture was heated for an additional 10 min at 125-130°C, during which the mixture was swirled by hand so that the salt that had been deposited on the glass wall was redissolved. After cooling to below 50°C a mixture of 5 ml of 36% HCl and 200 ml of ice-water was added and the obtained solution was extracted with small portions of diethyl ether. The ethereal solutions were washed with water and subsequently dried over magnesium sulfate. The solvent was removed by evaporation in a water-pump vacuum... 

Photochromic silver—copper haUde films were produced by vacuum evaporation and deposition of a mixture of the components onto a sUicate glass substrate (13). The molar ratio of the components was approximately 9 1 (Ag Cu) and film thicknesses were in the range of 0.45—2.05 p.m. Coloration rate upon uv exposure was high but thermal fade rates were very slow when compared with standard silver haUde glass photochromic systems. 

One gram of 6,7-dihydro-5H-dibenz[c,e] azepine hydrochloride was dissolved in water, made alkaline with concentrated ammonia, and the resultant base extracted twice with benzene. The benzene layers were combined, dried with anhydrous potassium carbonate, and mixed with 0.261 g of allyl bromide at 25°-30°C. The reaction solution became turbid within a few minutes and showed a considerable crystalline deposit after standing 3 A days. The mixture was warmed VA hours on the steam bath in a loosely-stoppered flask, then cooled and filtered. The filtrate was washed twice with water and the benzene layer evaporated at diminished pressure. The liquid residue was dissolved in alcohol, shaken with charcoal and filtered. Addition to the filtrate of 0.3 gram of 85% phosphoric acid in alcohol gave a clear solution which, when seeded and rubbed, yielded 6-allyl-6,7-dihydro-5H-dlbenz[c,e] azepine phosphate, MP about 211°-215°C with decomposition. 

These are semisolid or solid substances formed in nature from crude oils after the volatile components have evaporated and the remainder has undergone oxidation and polymerization. They are also referred to as bitumens, waxes, and pitch. These materials are believed to consist of mixtures of complex organic molecules of high molecular weight. As with crude oils, which contain thousands of different chemical compounds, an exact chemical analysis for identification and composition is impractical to perform on the solid deposits of petroleum. 

In a typical reaction 100 - 200 mg of metal [Cr or Ni] was evaporated from a preformed alumina crucible over a period of 60 - 90 min and deposited into a mixture of 2 in poly(dimethylsiloxane) [Petrarch Systems 0.1 P.] within a rotary solution metal vapor reactor operating at 10 4 torr. The reaction flask was cooled to approximately 270 K by an iced-water bath. For a description of the apparatus see Chapter 3 of reference 4. The product in each case was a dark orange viscous liquid and was characterized as obtained from the reaction vessel. 

As discussed in section 2.2, a mixture of AMP and AA showed two solid condensed phases above and below about 30 mN m- [5,10]. A loosely stacked structure of two porphyrins was proposed for LB films prepared at higher surface pressures than 30 mNmr1, which was caused by squeezing-out of a monomolecular structure formed at lower surface pressure [5,10]. In this section, photoelectric characteristics of LB films containing AMP and AA deposited at two solid condensed phases will be discussed in relation to multilayer structure and the anisotropic intermolecular tunneling rates [87]. Seven monolayers of 1 5 or 1 10 mixture of AMP and AA were deposited at 20 and 50 mN m-1 on an ITO plate at 18 °C to form stable Y-type LB films. Aluminum was vacuum evaporated onto LB films as sandwich-type electrodes at 10-6 Torr. Steady photocurrents were measured in a similar manner as mentioned above. 

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