Acetalization, bath, composition

Quantitative studies of solid-state organic reactions were performed by Glazman (267. 268). Equal amounts of acetic anhydride and 2-aminothiazole (grain diameter 0.15 mm) were mixed for 20 rain, and the mixture was heated in a glycerol bath at 0.5°C per minute. Heating curves showed that the reaction starts in the solid phase the use of an eutectic composition of organic reactants increases the yields. 

Fig. 5. Composition of cellulose acetate butyrate (propionate) as a function of butyryl (propionyl) content of esterification bath.

B. Reduction of Dinitrodurene.—A solution of 90 g. of dini-trodurene in 1 1. of glacial acetic acid is boiled in a 12-I. flask (Note 6) 700 g. of stannous chloride is dissolved in 800 cc. of concentrated hydrochloric acid and heated to boiling. The heat is removed from the acetic acid solution of the nitro compound, and the stannous chloride solution is poured very carefully (during about ten minutes) into the dinitrodurene solution. The reaction is complete in fifteen minutes, and as the solution cools the stannic chloride compound of the diamine begins to crystallize. The reaction mixture is cooled to io° in an ice-water bath, and the solid is filtered off by suction, washed twice with 50 cc. of 95 per cent ethyl alcohol and twice with 50 cc. of ether, and dried. The filtrates from the tin compound contain very little of the reduction product and may be discarded. The composition of this compound is [G (CH i)4(NH2-HCI)2l2-SnCl4, and it crystallizes from the reaction mixture in fine, glistening plates which are almost colorless. The yield is 145 g. (97 per cent of the theoretical amount). 

Films of various stoichiometries of Sn-S have been deposited from carboxylic acid (acetic, propionic, butyric) solutions of elemental S and SnCli. Depending on deposition conditions, in particular whether some water was present and how much, as well as the presence of complexing agents, films of approximate composition SnS, SniSs, or SnS2 could be formed. Interestingly, various Sn-S films were also formed on the walls of the deposition vessel above the liquid level (by several centimeters) this was attributed to reaction between volatile SnCU and H2S, both formed in the deposition bath. 

Due to its characteristic pine-needle odor, bomyl acetate is frequently used in conifer needle compositions, soap, bath products, room sprays, and pharmaceutical products. 

To test the solubility of a solid, transfer an amount roughly estimated to be about 10 mg (the amount that forms a symmetrical mound on the end of a stainless steel spatula) into a 10 x 75-mm test tube and add about 0.25 mL of solvent from a calibrated dropper or pipette. Stir with a fire-polished stirring rod (4-mm), break up any lumps, and determine if the solid is readily soluble at room temperature. If the substance is readily soluble in methanol, ethanol, acetone, or acetic acid at room temperature, add a few drops of water from a wash bottle to see if a solid precipitates. If it does, heat the mixture, adjust the composition of the solvent pair to produce a hot solution saturated at the boiling point, let the solution stand undisturbed, and note the character of the crystals that form. If the substance fails to dissolve in a given solvent at room temperature, heat the suspension and see if solution occurs. If the solvent is flammable, heat the test tube on the steam bath or in a small beaker of water kept warm on the steam bath or a hot plate. If the solid completely dissolves, it can be declared readily soluble in the hot solvent if some but not all dissolves, it is said to be moderately soluble, and further small amounts of solvent should then be added until solution is complete. When a substance has been dissolved in hot solvent, cool the solution by holding the flask under the tap and, if necessary, induce crystallization by rubbing the walls of the tube with a stirring rod to make sure that the concentration permits crystallization. Then reheat to dissolve the solid, let the solution stand undisturbed, and inspect the character of the ultimate crystals. 

The composite specimen is entered into a bath containing 20 per cent of sodium sulphate crystals and 5 per cent of acetic acid (30 per cent). The temperature is raised to 98 + 2°C (208° + 4°F) over a period of 30 minutes, at which it is then maintained for a further 30 minutes, and then 2 per cent of potassium dichromate is added and the temperature is maintained at 98 2°C for another 60 minutes. 

Various experimental conditions required for CBD on ITO and Sn02 substrates have been identified [337-343]. The chemical bath was based on ammonium acetate (0.5-10 M), ammonium hydroxide (1-6%), cadmium acetate or cadmium chloride (0.1-10 M), and thiourea (0.1-10" M), containing different concentrations and types heteropolyacids (10" -10" M). The deposition temperature varied from 50 to 95 °C and the deposition time from 10 minutes to 6 hours. The electrode surface area was 8cml The annealing temperature was varied from 200 to 500 C. The effect of the heteropolyacid on the morphology and the chemical composition of the films and on the CdS/CdTe heteroj unction parameters FF. t ) was... 

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