Red fuming nitric acid (RFNA) is a storable oxidizer used as a rocket propellant. It consists of 84% nitric acid (HNO3), 13% dinitrogen tetroxide (N2O4) and 1–2% water.[1] The color of red fuming nitric acid is due to the dinitrogen tetroxide, which breaks down partially to form nitrogen dioxide. The nitrogen dioxide dissolves until the liquid is saturated, and produces toxic fumes with a suffocating odor. RFNA increases the flammability of combustible materials and is highly exothermic when reacting with water.
It is usually used with an inhibitor (with various, sometimes secret, substances, including hydrogen fluoride;[2] any such combination is called inhibited RFNA, IRFNA) because nitric acid attacks most container materials. Hydrogen fluoride for instance will passivate the container metal with a thin layer of metal fluoride, making it nearly impervious to the nitric acid.
It can also be a component of a monopropellant; with substances like amine nitrates dissolved in it, it can be used as the sole fuel in a rocket. This is inefficient and it is not normally used this way.
During World War II, the German military used RFNA in some rockets. The mixtures used were called S-Stoff (96% nitric acid with 4% ferric chloride as an ignition catalyst[3]) and SV-Stoff (94% nitric acid with 6% dinitrogen tetroxide) and nicknamed Salbei (sage).
Inhibited RFNA was the oxidizer of the world's most-launched light orbital rocket, the Kosmos-3M. In former-Soviet countries inhibited RFNA is known as Mélange.
Other uses for RFNA include fertilizers, dye intermediates, explosives, and pharmaceutical acidifiers. It can also be used as a laboratory reagent in photoengraving and metal etching.[4]
When RFNA is used as an oxidizer for rocket fuels, it usually has a HF content of about 0.6%. The purpose of the HF is to act as a corrosion inhibitor by forming a metal fluoride layer on the surface of the storage vessels.
To test the water content, a sample of 80% HNO3, 8–20% NO2, and the rest H2O depending on the varied amount of NO2 in the sample. When the RFNA contained HF, there was an average H2O% between 2.4% and 4.2%. When the RFNA did not contain HF, there was an average H2O% between 0.1% and 5.0%. When the metal impurities from corrosion were taken into account, the H2O% increased, and the H2O% was between 2.2% and 8.8%
Stainless steel, aluminium alloys, iron alloys, chrome plates, tin, gold and tantalum were tested to see how RFNA affected the corrosion rates of each. Experiments were performed using 16% and 6.5% RFNA samples and the different substances listed above. Many different stainless steels showed resistance to corrosion. Aluminium alloys did not endure as well as stainless steels especially in high temperature, but the corrosion rates were not high enough to prohibit the use of this with RFNA. Tin, gold and tantalum showed high corrosion resistance similar to that of stainless steel. These materials are better though because at high temperatures the corrosion rates did not increase much. Corrosion rates at elevated temperatures increase in the presence of phosphoric acid. Sulfuric acid decreased corrosion rates.
^V. S. Sugur; G. L. Manwani (October 1983). "Problems in Storage and Handling of Red Fuming Nitric Acid". Defence Science Journal. 33 (4): 331–337. doi:10.14429/dsj.33.6188.
^Clark, John D. (1972). Ignition! An Informal History of Liquid Rocket Propellants(PDF). Rutgers University Press. p. 62. ISBN0-8135-0725-1.
^Clark, John D. (1972). "9: What Ivan Was Doing" (PDF). Ignition! An Informal History of Liquid Rocket Propellants. Rutgers University Press. p. 116. ISBN0-8135-0725-1.
^O'Neil, Maryadele J. (2006). The Merck index: an encyclopedia of chemicals, drugs, and biologicals. Merck. p. 6576. ISBN978-0-911910-00-1.
^ abKarplan, Nathan; Andrus, Rodney J. (October 1948). "Corrosion of Metals in Red Fuming Nitric Acid and in Mixed Acid". Industrial and Engineering Chemistry. 40 (10): 1946–1947. doi:10.1021/ie50466a021.
^Phelps, Edson H.; Lee, Fredrick S.; Robinson, Raymond B. (October 1955). Corrosion Studies in Fuming Nitric Acid(PDF) (Technical report). Wright Air Development Center. 55-109. (PDF) from the original on July 27, 2018. Retrieved 2024-01-02.
^Burns, E. A.; Muraca, R. F. (1963). "Determination of Water in Red Fuming Nitric Acid by Karl Fischer Titration". Analytical Chemistry. 35 (12): 1967–1970. doi:10.1021/ac60205a055.
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April 30, 2024
fuming, nitric, acid, rfna, storable, oxidizer, used, rocket, propellant, consists, nitric, acid, hno3, dinitrogen, tetroxide, n2o4, water, color, fuming, nitric, acid, dinitrogen, tetroxide, which, breaks, down, partially, form, nitrogen, dioxide, nitrogen, d. Red fuming nitric acid RFNA is a storable oxidizer used as a rocket propellant It consists of 84 nitric acid HNO3 13 dinitrogen tetroxide N2O4 and 1 2 water 1 The color of red fuming nitric acid is due to the dinitrogen tetroxide which breaks down partially to form nitrogen dioxide The nitrogen dioxide dissolves until the liquid is saturated and produces toxic fumes with a suffocating odor RFNA increases the flammability of combustible materials and is highly exothermic when reacting with water Red fuming nitric acid Names IUPAC name Nitric acid Other names Red fuming nitric acid Identifiers CAS Number 52583 42 3 Y ChemSpider None Properties Chemical formula HNO3 NO2 Appearance Liquid red fumes Density Increases as free NO2 content increases Boiling point 83 C 181 F 356 K Solubility in water Miscible in water Hazards Occupational safety and health OHS OSH Main hazards Skin and metal corrosion serious eye damage toxic oral dermal pulmonary severe burns Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references It is usually used with an inhibitor with various sometimes secret substances including hydrogen fluoride 2 any such combination is called inhibited RFNA IRFNA because nitric acid attacks most container materials Hydrogen fluoride for instance will passivate the container metal with a thin layer of metal fluoride making it nearly impervious to the nitric acid It can also be a component of a monopropellant with substances like amine nitrates dissolved in it it can be used as the sole fuel in a rocket This is inefficient and it is not normally used this way During World War II the German military used RFNA in some rockets The mixtures used were called S Stoff 96 nitric acid with 4 ferric chloride as an ignition catalyst 3 and SV Stoff 94 nitric acid with 6 dinitrogen tetroxide and nicknamed Salbei sage Inhibited RFNA was the oxidizer of the world s most launched light orbital rocket the Kosmos 3M In former Soviet countries inhibited RFNA is known as Melange Other uses for RFNA include fertilizers dye intermediates explosives and pharmaceutical acidifiers It can also be used as a laboratory reagent in photoengraving and metal etching 4 Contents 1 Compositions 2 Corrosion 3 See also 4 References 5 External linksCompositions editIRFNA IIIa 83 4 HNO3 14 NO2 2 H2O 0 6 HF IRFNA IV HDA 54 3 HNO3 44 NO2 1 H2O 0 7 HF S Stoff 96 HNO3 4 FeCl3 SV Stoff 94 HNO3 6 N2O4 AK20 80 HNO3 20 N2O4 AK20F 80 HNO3 20 N2O4 fluorine based inhibitor AK20I 80 HNO3 20 N2O4 iodine based inhibitor AK20K 80 HNO3 20 N2O4 fluorine based inhibitor AK27I 73 HNO3 27 N2O4 iodine based inhibitor AK27P 73 HNO3 27 N2O4 fluorine based inhibitorCorrosion editHydrofluoric acid content of IRFNA 5 6 When RFNA is used as an oxidizer for rocket fuels it usually has a HF content of about 0 6 The purpose of the HF is to act as a corrosion inhibitor by forming a metal fluoride layer on the surface of the storage vessels Water content of RFNA 7 To test the water content a sample of 80 HNO3 8 20 NO2 and the rest H2O depending on the varied amount of NO2 in the sample When the RFNA contained HF there was an average H2O between 2 4 and 4 2 When the RFNA did not contain HF there was an average H2O between 0 1 and 5 0 When the metal impurities from corrosion were taken into account the H2O increased and the H2O was between 2 2 and 8 8 Corrosion of metals in RFNA 5 Stainless steel aluminium alloys iron alloys chrome plates tin gold and tantalum were tested to see how RFNA affected the corrosion rates of each Experiments were performed using 16 and 6 5 RFNA samples and the different substances listed above Many different stainless steels showed resistance to corrosion Aluminium alloys did not endure as well as stainless steels especially in high temperature but the corrosion rates were not high enough to prohibit the use of this with RFNA Tin gold and tantalum showed high corrosion resistance similar to that of stainless steel These materials are better though because at high temperatures the corrosion rates did not increase much Corrosion rates at elevated temperatures increase in the presence of phosphoric acid Sulfuric acid decreased corrosion rates See also editWhite fuming nitric acidReferences edit V S Sugur G L Manwani October 1983 Problems in Storage and Handling of Red Fuming Nitric Acid Defence Science Journal 33 4 331 337 doi 10 14429 dsj 33 6188 Clark John D 1972 Ignition An Informal History of Liquid Rocket Propellants PDF Rutgers University Press p 62 ISBN 0 8135 0725 1 Clark John D 1972 9 What Ivan Was Doing PDF Ignition An Informal History of Liquid Rocket Propellants Rutgers University Press p 116 ISBN 0 8135 0725 1 O Neil Maryadele J 2006 The Merck index an encyclopedia of chemicals drugs and biologicals Merck p 6576 ISBN 978 0 911910 00 1 a b Karplan Nathan Andrus Rodney J October 1948 Corrosion of Metals in Red Fuming Nitric Acid and in Mixed Acid Industrial and Engineering Chemistry 40 10 1946 1947 doi 10 1021 ie50466a021 Phelps Edson H Lee Fredrick S Robinson Raymond B October 1955 Corrosion Studies in Fuming Nitric Acid PDF Technical report Wright Air Development Center 55 109 Archived PDF from the original on July 27 2018 Retrieved 2024 01 02 Burns E A Muraca R F 1963 Determination of Water in Red Fuming Nitric Acid by Karl Fischer Titration Analytical Chemistry 35 12 1967 1970 doi 10 1021 ac60205a055 External links editNational Pollutant Inventory Nitric Acid Fact Sheet https web archive org web 20030429160808 http www astronautix com props nitidjpx htm Retrieved from https en wikipedia org w index php title Red fuming nitric acid amp oldid 1209767837, wikipedia, wiki, book, books, library,
