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Hydrofluoric acid



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Product details:

- Product Name: Hydrofluoric acid

- Formulas : HF

- Chemical composition : China - 55% - 25kg

- Product Type: Chemicals for heat systems

Product description :

Hydrofluoric acid (HF) is a solution of hydrogen fluoride in water. It is a valued source of fluorine and is a precursor to numerous pharmaceuticals such as fluoxetine (Prozac) and diverse materials such as PTFE (Teflon).
Hydrofluoric acid is a highly corrosive acid, capable of dissolving many materials, especially oxides. Its ability to dissolve glass has been known since the 17th century, even before hydrofluoric acid had been prepared in large quantities by Carl Wilhelm Scheele in 1771.[2] Because of its high reactivity toward glass and moderate reactivity toward many metals, hydrofluoric acid is usually stored inplastic containers (although PTFE is slightly permeable to it).[3]
Hydrogen fluoride gas is an acute poison that may immediately and permanently damage lungs and the corneas of the eyes.Aqueous hydrofluoric acid is a contact-poison with the potential for deep, initially painless burns and ensuing tissue death. By interfering with body calcium metabolism, the concentrated acid may also cause systemic toxicity and eventual cardiac arrest and fatality, after contact with as little as 160 cm2 (25 square inches) of skin.
Uses
[edit]Oil refining

In a standard oil refinery process known as alkylationisobutane is alkylated with low-molecular-weight alkenes (primarily a mixture ofpropylene and butylene) in the presence of the strong acid catalyst derived from hydrofluoric acid. The catalyst protonates the alkenes (propylene, butylene) to produce reactive carbocations, which alkylate isobutane. The reaction is carried out at mild temperatures (0 and 30 °C) in a two-phase reaction.

[edit]Production of organofluorine compounds
The principal use of hydrofluoric acid is in organofluorine chemistry. Many organofluorine compounds are prepared using HF as the fluorine source, including Teflonfluoropolymersfluorocarbons, and refrigerants such as freon.[3]
[edit]Production of fluorides
Most high-volume inorganic fluoride compounds are prepared from hydrofluoric acid. Foremost are Na3AlF6cryolite, and AlF3,aluminium trifluoride. A molten mixture of these solids serves as a high-temperature solvent for the production of metallic aluminium. Given concerns about fluorides in the environment, alternative technologies are being sought. Other inorganic fluorides prepared from hydrofluoric acid include sodium fluoride anduranium hexafluoride.[3]
[edit]Etchant and cleaning agent
The ability of hydrofluoric acid to dissolve metal oxides is the basis of several applications. It removes oxide impurities from stainless steel, a process called pickling, and siliconwafers in the semiconductor industry. In this regard it is also referred to as BHF, (when Buffered with Ammonium Fluoride), and BOE (for Buffered Oxide Etch). It is a significant constituent of Wright Etch and the similar HNA (HF+Nitric+Acetic Acid) etch. In similar manner, it is also used to etch glass. A 5% to 9% hydrofluoric acid gel is also commonly used to etch all ceramic dental restorations to improve bonding.[5] For similar reasons, dilute hydrofluoric acid is a component of household rust stain remover and in car washes in "wheel cleaner" compounds.[6] Hydrofluoric acid attacks glass by reaction with silicon dioxide to form gaseous or water-soluble silicon fluorides. This dissolution process proceeds as follows:
SiO2 + 4 HF → SiF4 (g) + 2 H2O
SiO2 + 6 HF → H2SiF6 + 2 H2O
Because of its ability to dissolve iron oxides as well as silica-based contaminants, hydrofluoric acid is used in pre-commissioning boilers that produce high-pressure steam.
[edit]Niche applications
Because of its ability to dissolve oxides, hydrofluoric acid is useful for dissolving rock samples (usually powdered) prior to analysis. In similar manner, this acid is used in acid macerations to extract organic fossils from silicate rocks. Fossiliferous rock may be immersed directly into the acid, or a cellulose nitrate film may be applied (dissolved in amyl acetate), which adheres to the organic component and allows the rock to be dissolved around it.[7]
Diluted hydrofluoric acid (1 to 3 %wt.) is used in the petroleum industry in a mixture with other acids (HCl or organic acids) in order to stimulate the production of water, oil, and gas wells specifically where sandstone is involved.[citation needed]
Hydrofluoric acid is also used by some collectors of antique glass bottles to remove so-called sickness from the glass, caused by acids (usually in the soil the bottle was buried in) attacking the soda content of the glass.[citation needed]

 


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