Acetic acid, calcium salt

A 3-1., three-necked flask fitted with a mechanical stirrer, a dropping funnel, and a thermometer is then charged with an aqueous solution of 2.2 moles of calcium hypochlorite [Hypochlorous acid, calcium salt] (Note 3), and the piperidine acetate prepared above is placed in the dropping funnel. The hypochlorite solution is stirred and cooled to 0° to — 5° with a methanol-ice bath, and the piperidine acetate is added dropwise over a period of 1.25 hours while the temperature is maintained below 0°. After a further 15 minutes of stirring, equal portions of the mixture are placed in two 2-1. separatory funnels and extracted three times with a total of about 1300 ml. of ether. The ether extract is placed in a 2-1. flask and dried over anhydrous sodium sulfate in a cold room at 4° overnight. After filtration to remove inorganic material, the bulk of the ether is removed by boiling on a water bath maintained below 60° (Note 4). 

Diethylene triamine penta-acetic acid, calcium-sodium salt PLEX PC Vikon... 

Sodium calciumedetate is the calcium chelate of the disodium salt of ethylenediaminetetra-acetic acid (calcium EDTA). It is effective in acute lead poisoning because of its capacity to exchange calcium for lead the lead chelate is excreted in the urine, leaving behind a harmless amount of calcium. Dimercaprol may usefully be combined with sodium calciumedetate when lead poisoning is severe, e.g. with encephalopathy. 

Acetic acid, calcium acetate, and sodium diacetate are widely used in human and veterinary medicine, cosmetics, and a variety of household products as buffering agents or antimicrobial agents. Considering the complete and rapid metabolism of acetic acid and its salts, their use in animal nutrition is not expected to contribute to human exposure. 

Hydrolysis of Peroxycarboxylic Systems. Peroxyacetic acid [79-21-0] is produced commercially by the controlled autoxidation of acetaldehyde (qv). Under hydrolytic conditions, it forms an equiHbrium mixture with acetic acid and hydrogen peroxide. The hydrogen peroxide can be recovered from the mixture by extractive distillation (89) or by precipitating as the calcium salt followed by carbonating with carbon dioxide. These methods are not practiced on a commercial scale. Alternatively, the peroxycarboxyHc acid and alcohols can be treated with an estetifying catalyst to form H2O2 and the corresponding ester (90,91) (see Peroxides and peroxy compounds). 

Titanium Silicides. The titanium—silicon system includes Ti Si, Ti Si, TiSi, and TiSi (154). Physical properties are summarized in Table 18. Direct synthesis by heating the elements in vacuo or in a protective atmosphere is possible. In the latter case, it is convenient to use titanium hydride instead of titanium metal. Other preparative methods include high temperature electrolysis of molten salt baths containing titanium dioxide and alkalifluorosiUcate (155) reaction of TiCl, SiCl, and H2 at ca 1150°C, using appropriate reactant quantities for both TiSi and TiSi2 (156) and, for Ti Si, reaction between titanium dioxide and calcium siUcide at ca 1200°C, followed by dissolution of excess lime and calcium siUcate in acetic acid. 

The rate of hydrolysis of cellulose acetate can be monitored by removing samples at intervals during hydrolysis and determining the solubiUty of the hydrolyzed acetate. When the desired DS is reached, the hydrolysis is stopped by neutralizing the catalyst with magnesium, calcium, or sodium salts dissolved in aqueous acetic acid. 

Solution Process. With the exception of fibrous triacetate, practically all cellulose acetate is manufactured by a solution process using sulfuric acid catalyst with acetic anhydride in an acetic acid solvent. An excellent description of this process is given (85). In the process (Fig. 8), cellulose (ca 400 kg) is treated with ca 1200 kg acetic anhydride in 1600 kg acetic acid solvent and 28—40 kg sulfuric acid (7—10% based on cellulose) as catalyst. During the exothermic reaction, the temperature is controlled at 40—45°C to minimize cellulose degradation. After the reaction solution becomes clear and fiber-free and the desired viscosity has been achieved, sufficient aqueous acetic acid (60—70% acid) is added to destroy the excess anhydride and provide 10—15% free water for hydrolysis. At this point, the sulfuric acid catalyst may be partially neutralized with calcium, magnesium, or sodium salts for better control of product molecular weight. 

This solution is then cooled and made slightly acid by adding about 275 cc. of 50 per cent acetic acid (Note 4). Salt is added if necessary to cause the ester to separate. The ester layer is separated, dried over calcium chloride and fractionally distilled under reduced pressure from a modified Claisen flask (Org. Syn. 1, 40). 

Addition of acetic or mineral acid to skimmed milk to reduce the pH value to 4.6, the isoelectric point, will cause the casein to precipitate. As calcium salts have a buffer action on the pH, somewhat more than the theoretical amount of acid must be used. Lactic acid produced in the process of milk souring by fermentation of the lactoses present by the bacterium Streptococcus lactis will lead to a similar precipitation. 

Crucibles fitted with permanent porous plates are cleaned by shaking out as much of the solid as possible, and then dissolving out the remainder of the solid with a suitable solvent. A hot 0.1 M solution of the tetrasodium salt of the ethylenediaminetetra-acetic acid is an excellent solvent for many of the precipitates [except metallic sulphides and hexacyanoferrates(III)] encountered in analysis. These include barium sulphate, calcium oxalate, calcium phosphate, calcium oxide, lead carbonate, lead iodate, lead oxalate, and ammonium magnesium phosphate. The crucible may either be completely immersed in the hot reagent or the latter may be drawn by suction through the crucible. 

Quinoline yellow (E 104, Cl Food Yellow 13) is a quinophthalone dye consisting of a mixture of disulfonates (minimum 80%), monosulfonates (maximum 15%), and trisulfonates (maximum 7%) as sodium salts, obtained by the sulfonation of 2-(2-quinolyl)-l,3-indandione. The calcium and potassium salts are also permitted. Quinoline yellow is a yellow powder or granules, soluble in water, sparingly soluble in ethanol. The absorption maximum is at 411 nm in aqueous acetic acid solution, pH 5, = 865. It is not permitted as food colorant in the US. "... 

Acetic acid or Acetic anhhydride von Schwartz, 1918, 34 Cooling is necessary to prevent possible explosion from contact of potassium permanganate (or the sodium or calcium salts) with acetic acid or acetic anhydride. See Oxygenated organic compounds, below... 

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