Calcium acetate, decomposition

Calcium acetate was formerly used to manufacture acetone by thermal decomposition ... 

Calcium ditungsiiaic in the anhydrous state was supposed by Lefort to result from the double decomposition of sodium ditungstate and calcium acetate, whilst concentration of the mother-liquor yielded crystals prc-sumed to be the trihydrate. However, the existence of these compounds is not established since the products obtained vary in composition. 

Ketones from Acids.— Another important reaction of acids is the formation of ketones and aldehydes by the decomposition of salts of the acids. When calcium acetate is heated the calcium remains combined with part of the two carboxyl groups as calcium carbonate and the two alkyl radicals become united by the remaining carbonyl group forming a ketone. 

Derivation (1) By the action of pyroligneous acid on iron filings, (2) double decomposition of ferrous sulfate with calcium pyrolignite (calcium acetate). 

In system F calcite was used as a calcium source for the formation of gehlenite. The reaction did not proceed as completely as with calcium acetate, as inferred from two observations 1) some of the calcium remained as calcium oxide upon decomposition of... 

In the two examples of double-salt decomposition which have just been mentioned, sufficient water was yielded to cause a partial liquefaction but other cases are known where this is not so. Thus, when copper calcium acetate is heated to a temperature of 75°, although decomposition of the double salt into the two single salts occurs as represented by the equation ... 

As already mentioned, the decomposition of copper calcium acetate into the single salts and saturated solution is accompanied by a contraction, and it was therefore to be expected that increase of pressure would lower the transition point. This expectation of theory was confirmed by experiment, for van t Hoff and Spring found that although the transition point under atmospheric pressure is about 75°, decomposition of the double salt took place even at the ordinary temperature when the pressure was increased to 6000 atm. ... 

Acetates.—Ferrous Acetate— Fe(CaHsOj)a—178.9—is formed by decomposition of ferrous sulfate by calcium acetate, in soluble, silky needles. 

Considerable interest has been shown in analytical methods for the determination of algin (68, 72, 78, 101, 158, 171, 21A, 292). Improvements were made in the Lefevre-Tollens hydrochloric acid decarboxylation method by McCready, Swenson, and Maclay (135, 143) to make it more adaptable to routine determinations. Kenyon and coworkers (148, 262, 271, 272) in a series of articles compared various methods for the determination of the carboxyl content of sugar acids. These included the calcium acetate-acetic acid method, the potentiometric titration method in the presence of sodium bromide, decarboxylation and determination of the isolated furfural. Percival and Ross (70, 187) described improvements in the colorimetric carbazole determination of algin. New analytical methods include the oxidation of algin with cerium sulfate (W) and Perlin s (188) recent report of the quantitative thermal decomposition of algin at 255 C. 

The beaker is chilled in an ice bath for 1 hour. The crystalline diacetate that separates is collected on a Buchner funnel and washed with three 20-ml. portions of cold water. After drying for 30 minutes on the funnel with suction, the diacetate is dried overnight in a vacuum desiccator containing calcium chloride (Note 4). The dried diacetate weighs 26.7-29.3 g. (83-91%) and melts at 158-159° with decomposition. The purity of the diacetate, determined by the titration method of Lucas, Kennedy, and Formo,3 is 97-98%, which is good enough for most purposes. The purity can be increased to 99-100% by a recrystallization from 5M acetic acid. 

Under suitable conditions, certain chemical reactions will give rise to nacreous sulphur the most satisfactory result is obtained by allowing slow inter-diffusion of solutions of sodium thiosulphate and potassium hydrogen sulphate to occur.7 Another method involves the gradual decomposition of sulphur chloride or bromide by the vapour of water or methyl alcohol at the ordinary temperature.8 The decomposition of calcium polysulphidcs by hydrochloric acid,9 and of hydrogen persulphide by the addition of alcohol, ether, ethyl acetate or other organic solvents, also yields sulphur of the desired modification. 

A method of reducing the number of carbon atoms in the molecule of an acid, especially a fatly acid hy the decomposition of its calcium or harium sail in the presence of a salt of acetic acid, followed by oxidation of the resulting methyl ketone ... 

The best method of preparation, however, is as follows 2 9 1 grams of aniline in dilute sulphuric acid (1 4) are diazotised at 3° C. with 9 5 grams of sodium nitrite and the solution, made neutral to Congo paper with sodium acetate, is added to a cold aqueous solution of 22 grams of potassium selenocyanate. After fifteen hours steam distillation gives a pale yellow oil, which, when dried over calcium chloride, boils at 134° C. at 10 mm. and at about 250° C. with decomposition at ordinary pressures. The yield is about 50 per cent. When nitrated at -5° C. with nitric acid (density 1 5), p-nitrophenyl selenocyanate and a very small amount of o-nitrophenyl selenocyanate are obtained. p-Chlorophenyl selenocyanate,... 

Addition of chloride ions (as solid calcium chloride, potassium chloride or sodium chloride) to aqueous solutions containing 40% of peroxyacetic acid and 1 % of acetic acid leads to a violently exothermic decomposition reaction. Chlorine is evolved, most of the liquid evaporates and the residue (often red coloured) deflagrates. 

A classic example of a solid—fluid ceramic powder synthesis reaction is that of calcination and dehydration of natural or synthetic raw materials. Calcination reactions are common for the production of many oxides from carbonates, hydrates, sulfates, nitrates, acetates, oxalates, citrates, and so forth. In general, the reactions produce an oxide and a volatile gaseous reaction product, such as CO2, SOg, or HgO. The most extensively studied reactions of this type are the decompositions of magnesium hydroxide, magnesium carbonate, and calcium carbonate. Depending on the particular conditions of time, temperature, ambient pressure of CO2, relative humidity, particle size, and so on, the process may be controlled by a surface reaction, gas diffusion to the reacting... 

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