Arsenite chlorinated

Two complementai y reviews of this subject are by Shah et al. AIChE Journal, 28, 353-379 [1982]) and Deckwer (in de Lasa, ed.. Chemical Reactor Design andTechnology, Martinus Nijhoff, 1985, pp. 411-461). Useful comments are made by Doraiswamy and Sharma (Heterogeneous Reactions, Wiley, 1984). Charpentier (in Gianetto and Silveston, eds.. Multiphase Chemical Reactors, Hemisphere, 1986, pp. 104—151) emphasizes parameters of trickle bed and stirred tank reactors. Recommendations based on the literature are made for several design parameters namely, bubble diameter and velocity of rise, gas holdup, interfacial area, mass-transfer coefficients k a and /cl but not /cg, axial liquid-phase dispersion coefficient, and heat-transfer coefficient to the wall. The effect of vessel diameter on these parameters is insignificant when D > 0.15 m (0.49 ft), except for the dispersion coefficient. Application of these correlations is to (1) chlorination of toluene in the presence of FeCl,3 catalyst, (2) absorption of SO9 in aqueous potassium carbonate with arsenite catalyst, and (3) reaction of butene with sulfuric acid to butanol. 

Jessen-Eller, K. and J.F. Crivello. 1998. Changes in metallothionein mRNA and protein after sublethal exposure to arsenite and cadmium chlorine in juvenile winter flounder. Environ. Toxicol. Chem. 17 891-896. 

Example. —20 grms. of bleaching powder were made up with water to a litre, and 25 c.e. were titrated with fV-standard sodium arsenite soln., i.e,. a soln. of such a concentration that 1 c.c. corresponded with 0 "00355 grm. of chlorine. After the addition of 46 c.c. of tbe standard soln., a drop of the liquid being titrated gives no coloration with starch and potassium iodide. Here 46 x0"00355=0"163 grm. of available chlorine was contained in 25 c.c. of the given soln. or 6"5 grms. per litre of the soln., i.e. in 20 grms. of the sample. Hence the sample contained 32 "5 per cent, of available chlorine. 

Barium Arsenide, Ba3As2.—By passing arsine over barium oxide at red heat Soubeiran 4 obtained a mixture of arsenide and arsenite. Lebeau 6 prepared the pure arsenide by reduction of barium arsenate with carbon in an electric furnace. Barium arsenide is very similar in properties to the arsenides of calcium and strontium it is slightly darker in colour, more readily fusible and more reactive chemically. Its density at 15° C. is 4-1. It burns spontaneously in fluorine, chlorine or bromine vapour. In oxygen it burns at about 300° C. and in sulphur vapour at dull red heat. 

The I2O7 content of the periodates described is determined as follows The weighed sample is covered with 20 ml. of water, and 5 to 10 drops of 6N HC1 is added to hasten solution. No chlorine is liberated from the acid of this concentration. The solution is diluted to 100 ml., made just alkaline to phenolphthalein paper with borax, buffered with borax and boric acid (Muller and Wegelin Z. anal. Chem., 52, 755-759 (1913), and an excess of potassium iodide is added. Under these conditions, the periodate is reduced to iodate. The liberated iodine is titrated with 0.1N arsenite. 

Agitate the solution for 1 h. After this period, remove any unreacted chlorine by adding one of the following (a) 1 g of ascorbic acid, (b) a few drops of 2% sodium arsenite solution, or (c) 10 drops of 3% H202, followed by 5 drops of 50% sodium thiosulfate solution. Insure that there is no residual chlorine as indicated from no color change with Kl-starch paper. 

Chlorine, carbonates, bicarbonates, and hydroxides are common interferences. The former is removed by adding a drop of 1% solution of sodium arsenite (NaAsOz). If the sample is basic, neutralize it with HN03. Sample may be diluted to reduce the interference effect. 

Production of ED is similar to that of MD, involving the ethylation of a chlorinated arsenite or arsenate salt, or reductions of arsenious oxide, AS4O6, a naturally occurring compoimd (Bartelt-Hunt et al., 2006). 

American Method. In America, a similar method was employed for the manufacture of ethyl dichloroarsine to that already described for methyl dichloroarsine. It consisted essentially in treating sodium arsenite with diethyl sulphate, then with diethyl sulphate, reducing the product obtained with sulphur dioxide and then chlorinating with hydrochloric acid. 

The amount of dosage specified is ordinarily determined from the residual in the ozonated water leaving the contact tanks. Residuals are determined by the standard o-tolidine arsenite test (1), as specified for free residual chlorine. Tests are made on the site, immediately on sampling, not after delay due to return to the laboratory. This is very important because of the rapid change in residual. 

Determined by standard o-tolidine-arsenite method for free residual chlorine (I). Determined by counts on agar, at 37° C. for 24 hours. 

The commercial solution of sodium hypochlorite contains 14-15% available chlorine, compared to 35-36% in bleaching powder. The concentration of hypochlorite in the bleaching bath generally varies from 1 to 3 g/1 available chlorine. The optimum bleaching conditions, however, depend on the degree of discolouration of the cloth and thus the temperature and time of reaction should be adjusted according to the requirement. The concentration of hypochlorite solution is normally estimated by means of standard thiosulphate or arsenite titration. 

The estimation by above method expresses chlorates as well as hypochlorites as available chlorine. The errors due to chlorates can be avoided by titration with an N/10 solution of sodium arsenite (Na HAsOj)... 

ARSENIOUS ACID or ARSENIOUS OXIDE or ARSENITE (1327-53-3) AsjOj Noncombustible solid. Reacts, possibly violently, with acids, aluminum, aluminum chloride, chlorine trifluoride, chromic oxide, fluorine, fluorides, halogens, hydrogen fluoride, mercury, oxygen fluoride, phosphorus pentoxide, rubidium acetylide, sodium chlorate, sodium hydroxide, sulfuric... 

LAPIS INFERNALIS (7761-88-8) A powerful oxidizer. Forms friction- and shock-sensitive compounds with many materials, including acetylene, anhydrous ammonia (produces compounds that are explosive when dry), 1,3-butadiyne, buten-3-yne, calcium carbide, dicopper acetylide. Contact with hydrogen peroxide causes violent decomposition to oxygen gas. Violent reaction with chlorine trifluoride, metal powders, nitrous acid, phosphonium iodide, red or yellow phosphorus, sulfur. Incompatible with acetylides, acrylonitrile, alcohols, alkalis, ammonium hydroxide, arsenic, arsenites, bromides, carbonates, carbon materials, chlorides, chlorosulfonic acid, cocaine chloride, hypophosphites, iodides, iodoform, magnesium, methyl acetylene, phosphates, phosphine, salts of antimony or iron, sodium salicylate, tannic acid, tartrates, thiocyanates. Attacks chemically active metals and some plastics, rubber, and coatings. 

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