Hydrofluoric acid gas

Thus operating cells need aluminum fluoride [7784-18-17, AIF., rather than cryoHte. Much aluminum fluoride is produced in a fluidized bed by the reaction of hydrofluoric acid gas and activated alumina made by partially calcining the alumina hydrate from the Bayer process... 

Aluminum fluoride is produced when partially dehydrated alumina hydrate reacts with hydrofluoric acids gas. The solid aluminum fluoride produced is cooled with noncontact cooling water prior to further processing, while the gases from the reactor are scrubbed with water to remove unreacted hydrofluoric acid from the gas stream. Aluminum fluoride is mainly used in the production of... 

SYNONYMS anhydrous hydrofluoric acid, fluorhydric acid, HFA, hydrofluoric acid gas... 

OFF-GASSING OF MATERIAL PROPERTIES Heated Freon will off-gas. Hydrofluoric acid gas is one hazardous by-product... 

Burns. Skin bums resulting from contact with pure fluorine gas are comparable to thermal bums and differ considerably from those produced by hydrogen fluoride (114). Fluorine bums heal much more rapidly than hydrofluoric acid bums. 

Toxicity. Sulfur tetrafluoride has an inhalation toxicity comparable to phosgene. The current OSHA standard maximum allowable concentration for human exposure in air is 0.4 mg/m (TWA) (54). On exposure to moisture, eg, on the surface of skin, sulfur tetrafluoride Hberates hydrofluoric acid and care must be taken to avoid bums. One case of accidental exposure of electrical workers to decomposed SF gas containing SF has been cited (108). 

Other developing or potential appHcations for lime are neutralization of tail gas from sulfuric acid plants, neutralization of waste hydrochloric and hydrofluoric acids and of nitrogen oxide (NO ) gases, scmbbing of stack gases from incinerators (qv), and of course, from small industrial coal-fired boilers. 

The perchloryl fluoride [7616-94-6] FCIO, the acyl fluoride of perchloric acid, is a stable compound. Normally a gas having a melting poiat of —147.7° C and a boiling poiat of —46.7°C, it can be prepared by electrolysis of a saturated solution of sodium perchlorate ia anhydrous hydrofluoric acid. Some of its uses are as an effective fluorinating agent, as an oxidant ia rocket fuels, and as a gaseous dielectric for transformers (69). 

Qua.driva.Ient, Zirconium tetrafluoride is prepared by fluorination of zirconium metal, but this is hampered by the low volatility of the tetrafluoride which coats the surface of the metal. An effective method is the halogen exchange between flowing hydrogen fluoride gas and zirconium tetrachloride at 300°C. Large volumes are produced by the addition of concentrated hydrofluoric acid to a concentrated nitric acid solution of zirconium zirconium tetrafluoride monohydrate [14956-11-3] precipitates (69). The recovered crystals ate dried and treated with hydrogen fluoride gas at 450°C in a fluid-bed reactor. The thermal dissociation of fluorozirconates also yields zirconium tetrafluoride. 

Treatment of chloroform, obtained by reacting methanol and chlorine, with the hydrofluoric acid yields monochlorodifluoromethane, also used as a refrigerant, which is a gas boiling at -40.8 C. 

Chemical Reactivity - Reactivity with Water Dissolves and forms a weak solution of hydrofluoric acid Reactivity with Common Materials In presence of moisture will corrode glass, cement and most metals. Flammable hydrogen gas may collect in enclosed spaces Stability During Transport Stable Neutralizing Agents for Acids and Caustics Flush with water, rinse with dilute solution of sodium of sodium bicarbonate or soda ash Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Anhydrous hydrogen fluoride rapidly absorbs moisture to form hydrofluoric acid, which is corrosive to most metals and results in tire formation of hydrogen gas in tire presence of moisture. Tlris corrosiveness can lead to equipment failure, and the potential buildup of hydrogen gas in confined areas makes for a fire and explosion Irazard. 

Anhydrous hydrogen fluoride and hydrofluoric acid react with substances containing silica and silicon oxide to form silicon tetrafluoridc and fluorosilic acid. SiF, a colorless gas at ambient temperature, is liighly toxic. An equilibrium mixture of SiF in the presence of moisture also contains hydrogen fluoride and hydrofluoric acid. 

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Although the total content of carbohydrate fractions of the three components is similar, as reported by Williams et al., 1990, it was found that protein-rich fractions have a significantly lower glucuronic acid content. Circular dichroism studies conducted on different GA fractions showed that only the AGP and GP components have a secondary structure (Renard et al., 2006). The AGP fraction was isolated by gel filtration chromatography and subjected to deglycosylation with hydrofluoric acid (HF) to separate the protein (Qi et al., 1991). About 400 amino acids were contained by the AGP protein fraction ( 33% are... 

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