<\/p>\n\n\n\n
Industrial nitric acid production uses the\u00a0Ostwald process. The combined Ostwald and\u00a0Haber processes\u00a0are extremely efficient, requiring only air and natural gas\u00a0feedstocks.<\/p>\n\n\n\n
The Ostwald process’ technical innovation creates the proper conditions under which anhydrous\u00a0ammonia\u00a0burns to\u00a0nitric oxide\u00a0(NO) instead of\u00a0dinitrogen\u00a0(N2).\u00a0The nitric oxide is then oxidized, often with\u00a0atmospheric oxygen, to\u00a0nitrogen dioxide\u00a0(NO2):<\/p>\n\n\n\n
2 NO + O2 \u2192 2 NO2<\/p>\n\n\n\n
The dioxide then disproportionates in\u00a0water\u00a0to nitric acid and the nitric oxide feedstock:<\/p>\n\n\n\n
3 NO2 + H2O \u2192 2 HNO3 + NO<\/p>\n\n\n\n
The net reaction is maximal oxidation of ammonia:<\/p>\n\n\n\n
NH3 + 2 O2 \u2192 HNO3 + H2O<\/p>\n\n\n\n
Dissolved nitrogen oxides are either stripped (in the case of white fuming nitric acid) or remain in solution to form\u00a0red fuming nitric acid.<\/p>\n\n\n\n
Commercial grade nitric acid solutions are usually between 52% and 68% nitric acid by mass, the\u00a0maximum distillable concentration. Further\u00a0dehydration\u00a0to 98% can be achieved with concentrated\u00a0H2SO4.Historically, higher acid concentrations were also produced by dissolving additional nitrogen dioxide in the acid, but the last plant in the\u00a0United States\u00a0ceased using that process in 2012.<\/p>\n\n\n\n
More recently, electrochemical means have been developed to produce anhydrous acid from concentrated nitric acid feedstock.<\/p>\n\n\n\n
Laboratory synthesis<\/p>\n\n\n\n
Laboratory-scale nitric acid syntheses abound. Most take inspiration from the industrial techniques.<\/p>\n\n\n\n
A wide variety of\u00a0nitrate\u00a0salts metathesize with\u00a0sulfuric acid\u00a0(H2SO4) \u2013 for example,\u00a0sodium nitrate:<\/p>\n\n\n\n
NaNO3 + H2SO4 \u2192 HNO3 + NaHSO4<\/p>\n\n\n\n
Distillation\u00a0at nitric acid’s 83\u00a0\u00b0C boiling point then separates the solid metal-salt residue.\u00a0The resulting acid solution is the 68.5% azeotrope, and can be further concentrated (as in industry) with either\u00a0sulfuric acid\u00a0or\u00a0magnesium nitrate.<\/p>\n\n\n\n
Alternatively, thermal decomposition of\u00a0copper(II) nitrate\u00a0gives nitrogen dioxide and oxygen gases; these are then passed through water or\u00a0hydrogen peroxide\u00a0as in the Ostwald process:<\/p>\n\n\n\n
2 Cu(NO3)2 \u2192 2 CuO + 4 NO2 + O2<\/p>\n\n\n\n
2 NO2 + H2O \u2192 HNO2 + HNO3 or 2 NO2 + H2O2 \u2192 2 HNO3<\/p>\n","protected":false},"excerpt":{"rendered":"
Industrial nitric acid production uses the\u00a0Ostwald process. The combined Ostwald and\u00a0Haber processes\u00a0are extremely efficient, requiring only air and natural gas\u00a0feedstocks. The Ostwald process’ technical innovation creates the proper conditions under which anhydrous\u00a0ammonia\u00a0burns to\u00a0nitric oxide\u00a0(NO) instead of\u00a0dinitrogen\u00a0(N2).\u00a0The nitric oxide is then oxidized, often with\u00a0atmospheric oxygen, to\u00a0nitrogen dioxide\u00a0(NO2): 2 NO + O2 \u2192 2 NO2 The dioxide then […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[],"class_list":["post-397","post","type-post","status-publish","format-standard","hentry","category-product-introduction"],"blocksy_meta":[],"yoast_head":"\n