Polythionic acid
WebNational Center for Biotechnology Information Web连硫酸，英文名是polythionic acid，是一种化学物质。连硫酸中均含有—S—S—键。例如，当n=2时，得到4个S原子直接相连的连四硫酸。不同连硫酸中分子结构和S的氧化态不同，因此性质和制备方法也不尽相同。
Polythionic acid
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WebSep 28, 2024 · Polythionic acids, whose general formula is H2SnO6, with n greater than 2, were discovered in the aqueous solution of SO2 and H2S, known as the Wackenroder … Webthat formation of polythionic acid due to presence of H 2 S in the process gas and H 2 0 in the system was responsible for initiation of SCC in RTJ components. Detailed metallurgical investigation was carried out to identify the probable causes that could have been responsible for formation polythionic acid in the process gas.
WebOct 1, 2009 · Also, most of the Fe- and Ni-based alloys are susceptible to stress corrosion cracking induced by polythionic acid. Therefore, the most viable solution to this problem … Polythionic acid is an oxoacid which has a straight chain of sulfur atoms and has the chemical formula Sn(SO3H)2 (n > 2). Trithionic acid (H2S3O6), tetrathionic acid (H2S4O6) are simple examples. They are the conjugate acids of polythionates. The compounds of n < 80 are expected to exist, and those of n < 20 … See more All polythionates anion contains chains of sulfur atoms attached to the terminal SO3H-groups. Names of polythionic acids are determined by the number of atoms in the chain of sulfur atoms: • H … See more Numerous acids and salts of this group have a venerable history, and chemistry systems, where they exist, dates back to the studies John Dalton devoted to the behavior of hydrogen sulfide in aqueous solutions of sulfur dioxide (1808). This solution now … See more H 2S react with SO 3 or HSO 3Cl, forming thiosulfuric acid H 2S 2O 3, as the analogous reaction with H 2S 2 forms disulfonomonosulfonic acid HS 2SO 3H; similarly … See more Polythionic acids are rarely encountered, but polythionates are common and important. Polythionic acids have been identified in crater lakes. The phenomenon may be useful to predict volcanic activity. See more
WebWhen acids act on thiosulphates, polythionic acids are formed.5 This is explained by reactions (b) and (c). The fact that the amount of hydrogen sulphide liberated is very … WebNov 4, 2024 · A thermal stabilization treatment at 899 -900 deg C for two hours is specified for increasing the corrosion resistance to intergranular corrosion and polythionic acid stress corrosion cracking. The ASTM standard for A-376 and A 312 gives this treatment for the stabilzed grade austenitic stainless steels as a supplementary requirement without …
WebNov 15, 2016 · Polythionic acid is defined as H 2 S x O 6; but it is the tetrathionic acid (H 2 S 4 O 6) that typically induces stress corrosion cracking in sensitized austenitic stainless …
WebSep 10, 2024 · Protection of Austenitic Stainless Steels and Other Austenitic Alloys from Polythionic Acid Stress Corrosion Cracking During a Shutdown of Refinery Equipment This standard practice provides mitigation methods to protect austenitic stainless steels and other austenitic alloys from PTA SCC that can occur during a shutdown of refinery … city fire sumter landingWebApr 12, 2024 · Polythionic acid stress corrosion cracking (PASCC) occurs in certain materials, such as austenitic stainless steel, under specific environmental conditions. It is … city firestoneWebJan 13, 2016 · Industrial water was used to dilute the polythionic acid. Therefore, the chlorine concentration was high in the polythionic acid aqueous solution that accumulated in the drain valve nozzle. In addition, the chlorine was concentrated by the evaporation of water due to high temperature after starting operation, and SCC occurred. city fire the villages entertainment calendarWebJul 27, 2001 · The polythionic acid then corrodes the chromium-depleted grain boundaries of the sensitized alloy. Since stainless steels are usually supplied to fabricators in the solution-annealed condition, sensitization is usually confined to weld affected zones. K. Phan . RE: polythionic acids dict object has no attribute addressWebFeb 20, 2014 · As per ASTM (SA 213, S2), the stabilization cycle is subjected to mutual agreement between the purchaser and the supplier. However the following is recommended cycle to follow ( as per one of the oil giants) Apply the following heat treatments: a) Solution annealing at 1040 – 1070 C for - hour per inch followed by water quenching for 321/321H ... dict object attribute update is read-onlyWebMay 6, 2024 · Two classic cases of stress corrosion cracking are seasonal cracking of brass in ammoniacal environment and sensitization and stress corrosion cracking of stainless steels in existence of chlorides, caustic, and polythionic acid. Presence of crack and other defects on the material surfaces accelerates the fracture processes. city fire sumter landing entertainmentWebIt describes the causes of stress-corrosion cracking in chloride, caustic, polythionic acid, and high-temperature environments and the correlating effects on austenitic, ferritic, duplex, martensitic, and precipitation hardening stainless steels and nickel-base alloys. city fire stations