Calcium chloride CAS

Calcium is produced by two methods. One method is the electrolysis of calcium chloride (Ca + 2C1 —> CaCy as the electrolyte at a temperature of 800°C, during which process metallic calcium cations (Ca ) are deposited at the cathode as elemental calcium metal. Calcium can also be produced through a thermal process under very low pressure (vacuum) in which lime is reduced by using aluminum. 

Octammino-calcium Chloride, [Ca(NH3)8]Cl2.—Anhydrous calcium chloride absorbs ammonia rapidly, increase in bulk takes place, and finally the mass falls to a white voluminous powder. Fused calcium chloride also absorbs ammonia at first rapidly, but as the reaction nears completion absorption is very slow. The composition corresponds to the octammine. 

Hexammino -calcium Chloride, [Ca(NH3)6]Cl2, is not stable, but tetrammino-calcium chloride, [Ca(NH3)4]Cl2, and diammino-calcium chloride, [Ca(NH3)2]Cl, exist in the stable state.3... 

Calcium Chloride. [CAS 10043-52-4], CaCL- 6ILO, while solid, solubility 536 g/100 g FLO at 20 C. absorbs waier from moist air, formed by reaction 11) of calcium carbonate or hydroxide and HCl. 2 of calcium hydroxide and ammonium chloride. See also Calcium Chloride. 

CALCIUM CHLORIDE. Calcium chloride. [CAS I004.7-52-4J. CaClj, is a white, crystalline salt that is very soluble in water. Solutions containing 30-45 wl % CaCh are used commercially. Of the alkaline-earth chlorides it is the most soluble in water, h is extremely hygroscopic and liberates large amounts of heat during water absorption and on dissolution. It forms a series of hydrates containing one. two, four, and six moles of water per mole of caJcium chloride (Table I). Another hydrate. CaCl 0.331 I O. has been identified, mol wi 116.98 94.8 wl % CaCl, heat of solution in water to infinite dilution. -71.37 kJ/mol (- 17.06 keal/mol). 

Calcium + Chlorine = Calcium Chloride Ca +2 + Cl -I = CaCl2 Figure 2.49... 

There are numerous studies of the diffusion rate of ions, principally the chlorides, in water saturated paste [138,145-149]. Migration of ions in hardened cement paste is not a simple diffusion. Ions are adsoihed on the surface of hydrated phases, in pores, or even react with hydrates. Therefore the diffusion coefficients cannot be considered in a classic manner. Their values derived from the Pick s equation should be considered as apparent or effective diffusion coefficients. For example it is known that CaCl2 reacts with aluminates and C3(A, Fl CaClj lOH O phase is formed. The basic calcium chloride Ca(OH)2 CaCl2-H20 can be also formed in some conditions. 

From X ray analysis it is seen that bleaching powder is a complex mixture of basic calcium hypochlorite and calcium chloride Ca(0Cl)2Ca(0H)2CaCl22H20. 

The success of the Solvay process lay in the efficient use of the ammonia obtained as a by-product in the coke industry. The key step involves the reaction of ammonia gas and carbon dioxide gas in a saturated sodium chloride solution. That results in the formation of sodium hydrogencarbonate (bicarbonate) NaHCOj and ammonium chloride. The sodium bicarbonate precipitate is filtered from the solution, dried and heated to form sodium carbonate. Carbon dioxide is obtained by heating limestone CaCOj in a lime kiln. One noteworthy feature of the Solvay process is the effective use and recycling of materials. The only ultimate by-product is calcium chloride Ca-CI2, for which the demand is limited. To some extent it is used for deicing roads in winter and for dust control on dirt roads in the summer. 

Place 50 g. of anhydrous calcium chloride and 260 g. (323 ml.) of rectified spirit (95 per cent, ethyl alcohol) in a 1-litre narrow neck bottle, and cool the mixture to 8° or below by immersion in ice water. Introduce slowly 125 g. (155 ml.) of freshly distilled acetaldehyde, b.p. 20-22° (Section 111,65) down the sides of the bottle so that it forms a layer on the alcoholic solution. Close the bottle with a tightly fitting cork and shake vigorously for 3-4 minutes a considerable rise in temperature occurs so that the stopper must be held well down to prevent the volatilisation of the acetaldehyde. Allow the stoppered bottle to stand for 24-30 hours with intermittent shaking. (After 1-2 hours the mixture separates into two layers.) Separate the upper layer ca. 320 g.) and wash it three times with 80 ml. portions of water. Dry for several hours over 6 g. of anhydrous potassium carbonate and fractionate with an efficient column (compare Section 11,17). Collect the fraction, b.p. 101-104°, as pure acetal. The yield is 200 g. 

Method B. In a 500 ml. round-bottomed flask, provided with a reflux condenser protected by a cotton wool (or calcium chloride) drying tube, place 59 g. of succinic acid and 102 g. (94-5 ml.) of redistilled acetic anhydride. Reflux the mixture gently on a water bath with occasional shaking until a clear solution is obtamed ca. 1 hour), and then for a further hour to ensure the completeness of the reaction. Remove the complete assembly from the water bath, allow it to cool (observe the formation of crystals), and finally cool in ice. Collect the succinic anhydride as in Method A. The yield is 45 g., m.p. 119-120°. 

Mix together in a 250 ml. flask carrying a reflux condenser and a calcium chloride drying tube 25 g. (32 ml.) of freshly-distilled acetaldehyde with a solution of 59-5 g. of dry, powdered malonic acid (Section 111,157) in 67 g. (68-5 ml.) of dry pyridine to which 0-5 ml. of piperidine has been added. Leave in an ice chest or refrigerator for 24 hours. Warm the mixture on a steam bath until the evolution of carbon dioxide ceases. Cool in ice, add 60 ml. of 1 1 sulphuric acid (by volume) and leave in the ice bath for 3-4 hours. Collect the crude crotonic acid (ca. 27 g.) which has separated by suction filtration. Extract the mother liquor with three 25 ml. portions of ether, dry the ethereal extract, and evaporate the ether the residual crude acid weighs 6 g. Recrystallise from light petroleum, b.p. 60-80° the yield of erude crotonic acid, m.p. 72°, is 20 g. 

In a 500 ml. bolt-head flask provided with a thermometer (reaching almost to the bottom) and a calcium chloride (or cotton wool) guard tube, place 100 g. of a-bromo-wo-valerj l bromide and 50 g. of dry, finely-divided urea. Start the reaction by warming the flask on a water bath the temperature soon rises to about 80°. Maintain this temperature for about 3 horns the mass will liquefy and then resolidify. Transfer the sticky reaction product to a large beaker containing saturated sodium bicarbonate solution, stir mechanically and add more saturated sodium bicarbonate solution in small quantities until effervescence ceases. Filter at the pump, suck as dry as possible and dry the crude bromural upon filter paper in the air. RecrystaUise the dry product from toluene. Alternatively, recrystaUise the moist product from hot water (ca. 700 ml.). The yield of pure brommal, m.p. 154-155°, is 28 g. 

In a 2 litre round-bottomed flask, fitted with a double surface reflux condenser, place 11-5 g. of clean sodium. Add 250 ml. of absolute alcohol in one portion if the reaction is unduly vigorous, immerse the flask momentarily in ice. When all the sodium has reacted, add 80 g. (76 ml.) of ethyl malonate (Section 111,153), followed by a solution of 30 g. of dry urea in 250 ml. of hot (ca. 70°) absolute alcohol. Shake the mixture well, fit a calcium chloride (or cotton wool) guard tube to the top... 

The incorporation of aluminum increases the blast effect of explosives but decreases the rates of detonation, fragmentation effectiveness, and shaped charge performance. Mixes with aluminum are made by first screening finely divided aluminum, adding it to a melted RDX—TNT slurry, and stirring until the mix is uniform. A desensitizer and calcium chloride may be incorporated, and the mixture cooled to ca 85°C then poured. Typical TNT-based aluminized explosives are the tritonals (TNT + Al), ammonals (TNT, AN, Al), minols (TNT, AN, Al) torpexes and HBXs (TNT, RDX, Al) (Table 14) (223-226). 

The calcium chloride content of Ca(OCl)2 slurries or filter cakes can be reduced or eliminated by reaction with concentrated, low salt NaOCl solution (181). 

Other processes also use the dibasic salt as an intermediate. Dibasic calcium hypochlorite can be prepared from filtrates from chlorinated lime slurries in various ways. In one process, the filtrate is returned to the slurry being chlorinated to keep it thin. This is designed to improve crystal growth. The dibasic crystals, together with water, are added to the slurry during chlorination and some dibasic salt is prepared by chlorination in addition to the dibasic salt made from filtrates (188). In another process, dibasic crystals are separated, slurried in water, and chlorinated to obtain a slurry of neutral Ca(OCl)2 2H20 in a mother Hquor of reduced calcium chloride content which is then filtered and air dried (191,192). 

Bleaching Powder. This material, known siace 1798, is made by chlorination of slightly moist hydrated lime, calcium hydroxide [1305-62-0] Ca(OH)2- It has the empirical formula Ca(OCl)2 CaCl2 Ca(OH)2 2H20. Its compositioa, loag a subject of coatroversy, was estabHshed by phase studies, microscopy, and x-ray diffraction techniques (241). The initial chlorination products are monobasic calcium chloride [14031-38-4] and dibasic calcium hypochlorite [12394-14-8] ... 

Equation (7) shows that when calcium chloride dissolves, ions are present—Ca+2(aq) and Cl (aq) ions. In this case, each calcium ion has the positive charge of two protons. Therefore it has twice the positive charge held by a sodium ion, Na+(aq). The chloride ion that forms, C (aq), is the same negative ion that is present in the sodium chloride solution, though it comes from the calcium chloride solid instead of the sodium chloride. Because both CaCUfsJ and... 

When two solutions are mixed, a precipitate may form. For example, suppose solutions of calcium chloride, CaCl2, and sodium sulfate, Na2S04, are mixed. The mixture contains both calcium ions, Ca+1, and sulfate ions, S04-2, so solid calcium sulfate may form. The solubility product permits us to predict with confidence whether it will or not. 

Discussion. Most hypochlorites are normally obtained only in solution, but calcium hypochlorite exists in the solid form in commercial bleaching powder which consists essentially of a mixture of calcium hypochlorite Ca(OCl)2 and the basic chloride CaCl2,Ca(0H)2,H20 some free slaked lime is usually present. The active constituent is the hypochlorite, which is responsible for the bleaching action. Upon treating bleaching powder with hydrochloric acid, chlorine is liberated ... 

---