Sodium carbonate reaction with calcium hydroxide

Causticization, the reaction of hydrated lime [1305-62-0], Ca(OH)2, with sodium carbonate to regenerate sodium hydroxide and precipitate calcium carbonate, is an important part of the Bayer process chemistry. 

Reactions of the Side Chain. Benzyl chloride is hydrolyzed slowly by boiling water and more rapidly at elevated temperature and pressure in the presence of alkaHes (11). Reaction with aqueous sodium cyanide, preferably in the presence of a quaternary ammonium chloride, produces phenylacetonitrile [140-29-4] in high yield (12). The presence of a lower molecular-weight alcohol gives faster rates and higher yields. In the presence of suitable catalysts benzyl chloride reacts with carbon monoxide to produce phenylacetic acid [103-82-2] (13—15). With different catalyst systems in the presence of calcium hydroxide, double carbonylation to phenylpymvic acid [156-06-9] occurs (16). Benzyl esters are formed by heating benzyl chloride with the sodium salts of acids benzyl ethers by reaction with sodium alkoxides. The ease of ether formation is improved by the use of phase-transfer catalysts (17) (see Catalysis, phase-thansfer). 

Pentaerythritol is made by mixing formaldehyde with calcium hydroxide in an aqueous solution held at 65-70 °C. Nitration of pentaerythritol can be achieved by adding it to concentrated nitric acid at 25-30 °C to form PETN. The crude PETN is removed by filtration, washed with water, neutralized with sodium carbonate solution and recrystallized from acetone. This manufacturing process for PETN results in 95% yield with negligible by-products. The process is summarized in Reaction 7.9 (overleaf). 

Small Quantities. Wear nitrile rubber gloves, laboratory coat, and eye protection. In the fume hood, place the phosphorus tribromide in a large evaporating dish. Cover with excess solid sodium carbonate or calcium carbonate. When the reaction has subsided, very slowly add the mixture to a pail of cold water. Allow it to stand for 24 hours. Test the pH of the solution and neutralize with sodium carbonate or dilute sodium hydroxide solution if necessary. Wash the solution into the drain.8... 

In the PPG-process, chlorine is reacted in a carbon dioxide stream with sodium carbonate to dichlorine monoxide and hypochlorous acid, which is dissolved in water. Reaction with a calcium hydroxide slurry yields calcium hypochlorite ... 

To illustrate these different kinds of equations, consider the preparation of precipitated calcium carbonate, CaC03. This white, fine powdery compound is used as a paper filler to brighten and retain ink, as an antacid (as in the trade-named Turns), and as a mild abrasive in toothpastes. One way to prepare this compound is to react calcium hydroxide, Ca(OH)2, with sodium carbonate, Na2C03. Let us look at the different ways to write the equation for this reaction. 

An important sector of heavy inorganic chemical manufacturing is the production of chlorine and sodium hydroxide — the chlor-alkali industry. The manufacture of these chemicals has a long history. Today they are produced simultaneously by the electrolysis of sodium chloride solutions, but this was not always the case. The two chemicals were originally manufactured by different routes. In the 19th century chlorine was made by the oxidation of hydrogen chloride (itself made by reaction of salt with sulfuric acid) using the Deacon process. Sodium hydroxide was prepared by the reaction of calcium hydroxide with sodium carbonate — the lime-soda process. 

Conduct the preparation in the fume cupboard. Dissolve 250 g. of redistilled chloroacetic acid (Section 111,125) in 350 ml. of water contained in a 2 -5 litre round-bottomed flask. Warm the solution to about 50°, neutralise it by the cautious addition of 145 g. of anhydrous sodium carbonate in small portions cool the resulting solution to the laboratory temperature. Dissolve 150 g. of sodium cyanide powder (97-98 per cent. NaCN) in 375 ml. of water at 50-55°, cool to room temperature and add it to the sodium chloroacetate solution mix the solutions rapidly and cool in running water to prevent an appreciable rise in temperature. When all the sodium cyanide solution has been introduced, allow the temperature to rise when it reaches 95°, add 100 ml. of ice water and repeat the addition, if necessary, until the temperature no longer rises (1). Heat the solution on a water bath for an hour in order to complete the reaction. Cool the solution again to room temperature and slowly dis solve 120 g. of solid sodium hydroxide in it. Heat the solution on a water bath for 4 hours. Evolution of ammonia commences at 60-70° and becomes more vigorous as the temperature rises (2). Slowly add a solution of 300 g. of anhydrous calcium chloride in 900 ml. of water at 40° to the hot sodium malonate solution mix the solutions well after each addition. Allow the mixture to stand for 24 hours in order to convert the initial cheese-Uke precipitate of calcium malonate into a coarsely crystalline form. Decant the supernatant solution and wash the solid by decantation four times with 250 ml. portions of cold water. Filter at the pump. 

Sodium chloride is found in salt beds, salt brines, and sea water throughout the world, and it is also mined is some locations. Consequently, sodium chloride is the source of numerous other sodium compounds. A large portion of the sodium chloride utilized is consumed in the production of sodium hydroxide (Eq. (11.23)). The production of sodium metal involves the electrolysis of the molten chloride, usually in the form of a eutectic mixture with calcium chloride. Sodium carbonate is an important material that is used in many ways such as making glass. It was formerly produced from NaCl by means of the Solvay process, in which the overall reaction is... 

Which of the following best represents the net ionic equation for the reaction of calcium hydroxide with an aqueous sodium carbonate solution ... 

Calcium chloride is obtained as a by-product in the manufacture of sodium carbonate (soda ash) by ammonia-soda (Solvay) process. The process involves the reaction of sodium chloride with calcium carbonate and ammonia. Calcium chloride is currently produced in bulk amounts by evaporation of natural underground brines. In the laboratory, calcium chloride can be prepared by treating bmestone with hydrochloric acid followed by evaporation of solution to obtain crystals. The crystals are dehydrated to obtain anhydrous salt. Calcium oxide or hydroxide may be used instead of carbonate. 

The Solvay process involves a series of partial reactions. The first step is calcination of calcium carbonate to form lime and CO2. Lime is converted to calcium hydroxide. The most crucial step of the process involves reacting brine solution with carbon dioxide and ammonia to produce sodium bicarbonate and ammonium chloride. Sodium bicarbonate converts to sodium carbonate. The calcium hydroxide and ammonium chloride react to form calcium chloride as the by-product. The partial reactions are shown below ... 

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