Distillation nitric acid

Nitric acid obtained in standard ammonia oxidation is usually 50 to 70% by weight aqueous solution. Pure nitric acid of 98-99% may be obtained either by extractive distillation or by direct strong nitric (DSN) processes. In the distillation method, concentrated nitric acid of 50-70% is distilled with 93% sulfuric acid in a steam-heated tower. Sulfuric acid acts as a dehydrating agent. The distilled nitric acid vapor is condensed to pure nitric acid, while sulfuric acid absorbing water from 50-70% nitric acid loses its strength to about 70% and collects at the bottom. The 70% sulfuric acid is concentrated back to 93%... 

Toon and Tolbert (1995) suggest that if Type I PSCs are primarily ternary solutions rather than crystalline NAT, the higher vapor pressure of HN03 over the solution would in effect distill nitric acid from Type I to Type II PSCs, assisting in denitrification of the stratosphere. This overcomes the problem that if Type II PSCs have nitric acid only by virtue of the initial core onto which the water vapor condenses, the amount of HN03 they could remove may not be very large. The supercooled H20-HN03 liquid layer observed by Zondlo et al. (1998) clearly may also play an important role in terms of the amount of HNO, that can exist on the surface of these PSCs. 

Samples were analyzed using both LA-ICP-MS and ICP-MS of solutions to assess the impact on the results of the sampling by laser ablation. For ICP-MS analysis, less than 1 mg of material was dissolved in double distilled nitric acid. SRMs BIO, B12, 51.13-4 and 71.32-4 were prepared the same way, to obtain... 

Lead Reflux about 5 g of sample, accurately weighed, with 30 mL of nitric acid for 1 h. Remove the reflux condenser, and attach a condenser to the flask. Continue to heat, and collect the distilled nitric acid. Allow the residue to cool, add 20 mL of water, and allow it to cool again. Add 2 mL of orthophosphoric acid, dilute to 100 mL with water, and determine the lead content of the solution as directed for Method I in Atomic Absorption Spectrophotometric Graphite Furnace Method under Lead Limit Test, Appendix IIIB. 

Use acid-cleaned [in a mixture of 5% sub-boiling, distilled nitric acid and 5% sub-boiling, distilled hydrochloric acid made up in deionized, distilled water (18 megohm), and thoroughly rinsed with deionized, distilled water (18 megohm)]... 

All oil samples were centrifuged and filtered through Whatman No. 1 or 5y Millipore filters prior to analysis. For viscous oils it was necessary to dilute the oils with benzene before clean-up. The benzene was removed from the filtered oils by vacuum evaporation. Polyethylene or quartz vials used for irradiation were washed with double distilled nitric acid followed by double-distilled water and acetone to remove surface impurities. 

From 1 to 1.8 ml. of distilled nitric acid is next added to the filtrate to lower the pH to about 2 upon boiling the solution, a deposit of sulfur is obtained. After standing for several hours this is removed by filtration. 

At the end of the 17 century interest arose in the difference between the natural products soda, sodium carbonate on one side and potash, potassium carbonate on the other. The former was called mineral alkali, the latter vegetable alkali. It was early established that there is a relationship between sea salt and soda and between saltpeter (potassium nitrate) and potash. Johaim Bohn in Leipzig made one of the first systematic observations in 1683. He distilled nitric acid with sea salt present, to prepare aqua regia. Crystals with an obvious cubic structure were deposited in the retort (he called it cubic saltpeter it was probably cubic sodium chloride). From the reaction between nitric acid and potash, without sea-salt present, he got beautiful crystals of quite a different form (presumably saltpeter, potassium nitrate, which crystaUizes in the orthorhombic system in prismatic crystals). 

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