nitric acid
nitric acid - Names and Identifiers
nitric acid - Physico-chemical Properties
| Molecular Formula | HNO3 |
| Molar Mass | 63.01 |
| Density | 1.41g/mLat 20°C |
| Melting Point | -42 °C |
| Boling Point | 120.5°C(lit.) |
| Flash Point | 120.5°C |
| Water Solubility | >100 g/100 mL (20 ºC) |
| Solubility | Miscible with water. |
| Vapor Presure | 8 mm Hg ( 20 °C) |
| Vapor Density | 1 (vs air) |
| Appearance | Liquid, Double Sub-Boiling Quartz Distillation |
| Specific Gravity | d 20/4 1.4826 |
| Color | colorless to deep yellow |
| Odor | Suffocating fumes detectable at <5.0 ppm |
| Exposure Limit | TLV-TWA 2 ppm (5 mg/m3) (ACGIH,MSHA, OSHA, and NIOSH); STEL 4 ppm(～10 mg/m3) (ACGIH). |
| Merck | 14,6577 |
| pKa | -1.3(at 25℃) |
| PH | 3.01(1 mM solution);2.04(10 mM solution);1.08(100 mM solution); |
| Storage Condition | Store at +2°C to +25°C. |
| Sensitive | Hygroscopic |
| Physical and Chemical Properties | Pure nitric acid is a colorless liquid. Generally with slightly yellow. Fuming nitric acid is a red-brown liquid that causes heavy smoke in the air and absorbs water. |
| Use | Basic chemical raw materials for the production of ammonium nitrate and phosphate nitrate |
nitric acid - Upstream Downstream Industry
nitric acid - Nature
Open Data Verified Data
A colorless or yellow fuming liquid with a asphyxiating odor. In the air to form a yellow to brown-red mist of gas. It can be freely miscible with water. Relative density L 503 l melting point -42 ℃, boiling point 83 ℃. Nitric acid is unstable, when light or heat will decompose and release nitrogen dioxide, which appears light yellow. Concentrated nitric acid is a strong oxidant, in case of organic matter, wood, etc. can cause combustion. Concentrated nitric acid containing trace oxides can react with almost all metals except aluminum and chromium-containing special steels, which can be passivated by concentrated nitric acid. The reaction with ethanol, turpentine, Coke, organic debris is very intense.
Last Update：2025-06-10 22:55:16
nitric acid - Preparation Method
Open Data Verified Data
with platinum as a catalyst, ammonia is oxidized to nitric oxide, and then air and concentrated nitric acid are all oxidized to ammonia dioxide, and then absorbed with concentrated nitric acid to generate fuming nitric acid, which is then desorbed.
Last Update：2025-06-10 22:55:16
nitric acid - Application
Open Data Verified Data
nitric acid is a strong oxidizing acid and has a corrosive effect on most metals. High concentration of nitric acid has a passivation effect on metals. Nitric acid is used to clean carbon steel, stainless steel, copper, brass, carbon steel a stainless steel equipment, can remove scale, rust, a-Fez 03 and magnetic Fe3 04 has a good dissolution force. In the process of biological wastewater treatment, it can be used as a nitrogen source in microbial nutrients. In addition, nitric acid is widely used in the manufacture of chemical fertilizers, chemical fibers, pharmaceuticals, dyes, rubber, etc., in the national defense industry, metallurgical industry, printing and dyeing industry and other industrial sectors, it is also an indispensable and important analytical chemical reagent.
Last Update：2025-08-19 16:24:40
nitric acid - Safety
Open Data Verified Data
nitric acid is toxic, Burns and erodes the mouth, esophagus and stomach, causing chest tenderness, Shock and death. Prolonged exposure to nitric acid vapor, can cause chronic bronchitis, chemical Pneumonia. Therefore, in the contact and use of nitric acid should be protected from nitric acid or its vapor into the body. The maximum allowable concentration of nitric acid in air is 5 mg/ml. It shall not be stored and mixed with organic matter, oxidant, combustible material, strong alkali, calcium carbide, metal powder, etc.
Last Update：2025-06-10 22:55:16
nitric acid - Reference Information
| pH range | 1 |
| NIST chemical information | information provided by: webbook.nist.gov (external link) |
| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| toxicity | see nitric acid. nitric acid on human skin can cause serious burns, cause dermatitis, and even erosion. Human eye nitrile is especially dangerous, can cause conjunctivitis, corneal erosion, and even blindness. The oxides of nitrogen and nitric acid vapor on the lungs very irritating, serious can cause pulmonary edema. If the skin burns, should immediately rinse with plenty of water, and with 2% ~ 3% sodium bicarbonate solution bandage. Such as small hands into the eyes, should immediately rinse with plenty of water, and sent to the hospital for treatment. The maximum allowable concentration in air is 5 mg/m3 (in NO2). The allowable limit in water is 20mg/L (in N). Personnel Engaged in nitric acid production should wear gas masks, protective glasses, acid-resistant gloves, work clothes, long series rubber boots and other labor protection articles. The workshop should be well ventilated and equipped with emergency shower facilities. Regular physical examination of lung function and teeth. |
| usage limit | is limited to GMP. |
| Use | for the production of ammonium nitrate, phosphate nitrate, also used as nitrating agent for organic synthesis, preparation of nitro compounds, used in metallurgy, mineral Processing, nuclear fuel reprocessing, etc. commonly used as analytical reagents, also used in organic synthesis and dye manufacturing is an important chemical raw material with a wide range of uses, mainly used in the manufacture of ammonium nitrate, calcium ammonium nitrate, nitrate phosphate fertilizer, nitrogen, phosphorus and potassium fertilizer. Organic industry for the manufacture of tetra-nitromethane, Nitro-hexane, l-nitropropane, 2, 4-dinitrophenoxyethanol and other nitro compounds. The dye industry is used for the synthesis of dye intermediates such as P-nitroanisole, 4,4 '-dinitrodiphenyl ether, P-nitrophenol and 2, 5-dichloronitrobenzene. The coating industry is used in the manufacture of nitro-varnish and nitro-enamel. The pharmaceutical industry is used for the manufacture of nitroacetophenone. Nitric acid acts as an oxidant to oxidize alcohols, anilines, and other chemicals. And has been used in the propellant of the rocket. Nitric acid is also a raw material for making nitrates of calcium, copper, silver, cobalt, and strontium. basic chemical raw materials, used in the preparation of ammonium nitrate, phosphate nitrate used as oxidant, also used in the manufacture of nitro compounds and explosives usually used as raw materials for the manufacture of nitric acid, nitro compounds and explosives. It is also used as an oxidizing agent. It is widely used in analysis and research. Dissolved metals. Medium of inorganic acids. Oxidant. Preparation of nitro compounds in organic synthesis. Preparation of nitrate, dye, fertilizer and pharmaceutical intermediates in inorganic synthesis. It is used as an etchant and a strong acidic cleaning etchant, and can be used in combination with glacial acetic acid, hydrogen peroxide, etc. |
| production method | with industrial nitric acid as raw material, after rectification, condensation and separation to remove impurities, the impurities were then removed by filtration through a microporous membrane to obtain colorless and transparent electronic grade nitric acid. The purified ammonia gas and air generate nitric oxide mixture under the action of catalyst. The mixed gas enters the primary oxidation Tower and the heavy oxidation section through heat recovery, and the oxidized gas is a mixed gas containing 6.35% nitrogen tetroxide. This gas enters the absorption section and reacts with concentrated nitric acid to generate fuming nitric acid (its composition is 30% N2O4;1%~ 2%H2O;68% ~ 69% HNO3). The initial oxidation and re-oxidation liquid is mixed and pressurized with fuming nitric acid generated in the absorption section, and reacts with oxygen from the oxygen tank in the autoclave at 5 Mpa to generate 31% N2O4,1.1% H2O,67 9% fuming nitric acid. After the fuming nitric acid is isolated by the separator, the gas is cooled and condensed by the cooler and condenser to 95.64% of the liquid nitrogen tetroxide, the cooler condenses the nitric acid containing dinitrogen tetroxide and the fuming nitric acid from the absorption section and the fuming nitric acid from the separator, drifts out dinitrogen tetroxide in the bleaching tower, and reacts with the nitric acid to generate 98% nitric acid, after cooling, it becomes concentrated nitric acid produced by direct method. The gas from the absorption section is washed by the washing section to become waste gas containing 0.02% of nitrogen dioxide. The exhaust gas is recovered by the exhaust gas heat exchanger and the exhaust gas turbine and vented. dilute nitric acid and concentrated nitric acid are described below. (A) dilute nitric acid industrial methods for the preparation of dilute nitric acid are atmospheric pressure method, comprehensive method, medium pressure method and GP double pressure method. The atmospheric pressure method is the oxidation of ammonia-air mixture at atmospheric pressure into nitrogen oxides, which are absorbed by a multi-stage packed absorption tower at atmospheric pressure to prepare dilute nitric acid. The tail gas is absorbed by alkali and discharged. The ammonia-air mixture purified by the comprehensive method is boosted by the blower, preheated and passed through the cardboard filter into the oxidation furnace to oxidize into nitric oxide. The gas enters the cooling scrubber, enters the oxidation tower for nitric oxide oxidation, then enters the acid absorption tower, and water is added at the top of the tower for absorption to generate dilute nitric acid. The nitric acid flowing out from the bottom of the tower enters the bleaching tower to prepare the dilute nitric acid product. The medium pressure method is to use the steam turbine and the tail gas expansion compressor to directly drive the air turbine compressor. By bleaching tower, oxidation Tower, absorption tower of dilute nitric acid products. The GP double pressure method is carried out using two oxidation furnaces operated in parallel. The generated gas is condensed and absorbed to obtain a dilute nitric acid product. Dilute nitric acid production of 4NH3+5O2 → 4NO + 6H2O2NO + O2 → 2NO23NO2 + H2O → 2HNO3 + NO (II) concentrated nitric acid industrial preparation of concentrated nitric acid methods are indirect method, direct method (see fuming nitric acid) distillation of hyperazeotropic acids. In the indirect method, dilute nitric acid is prepared first, and then concentrated nitric acid is prepared through purification, rectification, condensation, bleaching and the like in the presence of a dehydrating agent. Magnesium nitrate, concentrated sulfuric acid and the like are used as the dehydrating agent. The super-azeotropic acid distillation includes the oxidation of ammonia, the preparation of super-azeotropic acid and the direct distillation. |
| category | corrosive article |
| toxicity grade | highly toxic |
| Acute toxicity | inhalation-rat LC50: 67 PPM/ 4 h |
| flammability hazard characteristics | combustible with H-forming porogen and turpentine; Highly toxic hydrogen cyanide gas in cyanide; explosive when exposed to strong oxidant; Toxic nitrogen oxide smoke generated by heat |
| storage and transportation characteristics | The warehouse was ventilated and dried at low temperature; With H pore forming agent, alkali, cyanide, flammable, separate storage of combustible materials |
| extinguishing agent | water mist, carbon dioxide, sand. |
| Occupational Standard | TWA 2 PPM ( 5 mg/m3); Tel 4 PPM (10 mg/m3) |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
| immediate life-and health-threatening concentration | 25 ppm |
Last Update：2024-05-30 16:47:25
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