Nitric acid calcium carbonate, reaction with

In the commonly used Welland process, calcium cyanamide, made from calcium carbonate, is converted to cyanamide by reaction with carbon dioxide and water. Dicyandiamide is fused with ammonium nitrate to form guanidine nitrate. Dehydration with 96% sulfuric acid gives nitroguanidine which is precipitated by dilution. In the aqueous fusion process, calcium cyanamide is fused with ammonium nitrate ia the presence of some water. The calcium nitrate produced is removed by precipitation with ammonium carbonate or carbon dioxide. The filtrate contains the guanidine nitrate that is recovered by vacuum evaporation and converted to nitroguanidine. Both operations can be mn on a continuous basis (see Cyanamides). In the Marquerol and Loriette process, nitroguanidine is obtained directly ia about 90% yield from dicyandiamide by reaction with sulfuric acid to form guanidine sulfate followed by direct nitration with nitric acid (169—172). 

When calcium carbonate goes into solution, it releases basic carbonate ions (COf ), which react with hydrogen ions to form carbon dioxide (which will normally remain in solution at deep-well-injection pressures) and water. Removal of hydrogen ions raises the pH of the solution. However, aqueous carbon dioxide serves to buffer the solution (i.e., re-forms carbonic acid in reaction with water to add H+ ions to solution). Consequently, the buffering capacity of the solution must be exceeded before complete neutralization will take place. Nitric acid can react with certain alcohols and ketones under increased pressure to increase the pH of the solution, and this reaction was proposed by Goolsby41 to explain the lower-than-expected level of calcium ions in backflowed waste at the Monsanto waste injection facility in Florida. 

Calcium nitrate may be prepared by the reaction of nitric acid with calcium carbonate or calcium sulfide ... 

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). 

This is an endothermic reaction of non-explosive character. It is evident from reaction (6a) why ammonium nitrate becomes acid during storage. Owing to the presence of free nitric acid in ammonium nitrate, its admixture with nitroglycerine may cause the latter to decompose in the course of time. Hence a little calcium carbonate, e.g. 0.3%, is very often added to ammonium nitrate destined for the manufacture of explosives including nitroglycerine. 

Preparation of Nitrobenzene. One hundred and fifty grams of concentrated sulfuric acid (d. 1.84) and 100 grams of nitric acid (d. 1.42) are mixed in a 500-cc. flask and cooled to room temperature, and 51 grams of benzene is added in small portions at a time with frequent shaking. Shaking at this point is especially necessary lest the reaction suddenly become violent. If the temperature of the mixture rises above 50-60°, the addition of the benzene is interrupted and the mixture is cooled at the tap. After all the benzene has been added, an air condenser is attached to the flask and the material is heated in the water bath for an hour at 60° (thermometer in the water). After cooling, the nitrobenzene (upper layer) is separated from the spent acid, washed once with water (the nitrobenzene is now the lower layer), then several times with dilute sodium carbonate solution until it is free from acid, then once more with water, dried with calcium chloride, and distilled (not quite to dryness). The portion boiling at 206-208° is taken as nitrobenzene. 

The mixture of the (R)-HMPC and the (S)-acetate 4 from the enzymatic hydrolysis was esterified with methanesulfonyl choride and triethylamine to afford a mixture of the corresponding (R)-sulfonate 5a and the (S)-acetate 4. The (S)-acetate 4 was unaffected by the sulfonation conditions. The resultant mixture of two esters, 4 and 5a, was hydrolyzed in the presence of a small amount of calcium carbonate. The (R)-sulfonate 5a was converted into the (S)-HMPC 6 as a result of inversion of configuration. On the other hand, the (S)-acetate 4, was hydrolyzed with retention of configuration. Consequently, all of the racemic acetate J3, was converted with maximum efficiency to the desired (S)-HMPC 6, by the sequence enzymatic hydrolysis and sulfonation followed by inversion of the chiral center in (R)-HMPC without separation of the (S)-acetate Similar transformations could also be carried out via nitrate ester intermediate 5b obtained from the reaction of the (R)-HMPC with nitric acid and acetic anhydride. 

Write reactions to show how nitric and sulfuric acids are produced in the atmosphere. Write reactions to show how the nitric and sulfuric acids in acid rain react with marble and limestone. (Both marble and limestone are primarily calcium carbonate.)... 

Compound 10b has been treated with a solution of the nitrating mixture made from acetic anhydride and nitric acid in dioxane affording nitro derivative 10c, with not very high yields. The catalytic reduction of nitro derivative 10c, carried out with hydrazine in ethanol in the presence of palladium on calcium carbonate, affords compound lOd. The guanidino group at C-5 has be i introduced by reaction of compound lOd with ( anamide in solution of hydrochloric acid affording the objective molecule 10. 

Goodman AL, Underwood GM, Grassian VH (2000) A laboratory study of the heterogeneous reaction of nitric acid on calcium carbonate particles. J Geophys Res 105 29053-29064 Gorbimov BZ, Kakutkina NA (1982) Ice crystal formation on aerosol particles with a non-uniform surface. J Aerosol Sci 13 21-28... 

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