Name | Hydrofluoric Acid |
Synonyms | fluoride hydrogen fluoride Hydrofluoric Acid Hydrogen Fluotride (~2~H)hydrogen fluoride Hydrogen fluoride,anhydrous Anhydrous Hydrogen Fluoride Hydrofluoric Acid, Ultratrace Hydrofluoric Acid, TraceGrade Hydrofluoric Acid, 70 Percent, Technical Hydrofluoric Acid, 48-52 Percent, Technical |
CAS | 7664-39-3 |
EINECS | 231-634-8 |
InChI | InChI=1/FH/h1H/i/hD |
Molecular Formula | FH |
Molar Mass | 20.01 |
Density | 1.15g/mLat 25°C(lit.) |
Melting Point | -35°C |
Boling Point | 105°C |
Flash Point | 112°C |
Water Solubility | soluble |
Vapor Presure | 25 mm Hg ( 20 °C) |
Vapor Density | 1.27 (vs air) |
Appearance | Liquid, Double Sub-Boiling Quartz Distillation |
Specific Gravity | 1.15 |
Color | max. 10 |
Odor | Acrid, irritating odor |
Exposure Limit | Ceiling limit 3 ppm (~2.5 mg/m3) as F(ACGIH); TWA 3 ppm (MSHA and OSHA). |
Merck | 14,4790 |
pKa | 3.17(at 25℃) |
PH | 3.27(1 mM solution);2.65(10 mM solution);2.12(100 mM solution) |
Storage Condition | Store at +5°C to +30°C. |
Stability | Stable. Hygroscopic. Incompatible with glass, alkali metals, light metals, alkaline earth metals |
Sensitive | Hygroscopic |
Physical and Chemical Properties | Density:1.15 Melting point:-35°C Boiling point:105°C Water solubility:soluble Colorless fuming liquid. |
Use | Used in atomic energy industry, system elements of fluorine, fluoride, can also be used as catalyst, fluoride agent, etcFor the manufacture of organic or inorganic fluoride, but also for stainless steel, non-ferrous metal pickling, glassware frosting and pickling, the treatment of frosting bulbs, etc |
Risk Codes | R26/27/28 - Very toxic by inhalation, in contact with skin and if swallowed. R35 - Causes severe burns R36/37/38 - Irritating to eyes, respiratory system and skin. R20/21/22 - Harmful by inhalation, in contact with skin and if swallowed. |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S7/9 - S36/37 - Wear suitable protective clothing and gloves. S28 - After contact with skin, wash immediately with plenty of soap-suds. S36 - Wear suitable protective clothing. |
UN IDs | UN 1790 8/PG 2 |
WGK Germany | 2 |
RTECS | MW7875000 |
TSCA | Yes |
HS Code | 28111100 |
Hazard Note | Corrosive |
Hazard Class | 8 |
Packing Group | II |
Toxicity | LC50 (15 min.) in rats, guinea pigs: 2689, 4327 ppm (Rosenholtz) |
hydrogen fluoride gas is obtained by decomposing fluorite with sulfuric acid and then absorbing with water.
hydrofluoric acid is an aqueous solution of hydrogen fluoride and is a colorless transparent liquid. The density was 1.15g/mL(so%HF) at 25 °c. It is highly corrosive to metals, glass, concrete, etc.
hydrofluoric acid can be used as a cleaning agent for stainless steel to remove oxides from metal surfaces and increase the corrosion resistance of stainless steel. Hydrofluoric acid is a weak inorganic acid, less corrosive to metals than sulfuric acid and hydrochloric acid. Hydrochloric acid at room temperature in addition to silicon scale, iron scale ability, can clean austenitic stainless steel, will not produce stress corrosion, cleaning time is short, high cleaning efficiency, good surface condition. But hydrofluoric acid on cast iron, titanium and other metal corrosion. It can be mixed with hydrochloric acid and nitric acid, and the content of hydrofluoric acid used alone is generally 1.0% to 2.0%.
It is highly corrosive and can corrode glass and nails. Inhalation of vapors should be avoided. Hydrofluoric acid is corrosive to the eyes, skin and mucous membranes, and inhalation can cause pulmonary edema. Skin contact caused by redness and burning sensation, eyes will appear blurred vision, Laryngalgia, Cough, Dyspnea after inhalation. After entering the digestive tract will cause Abdominal Pain, Diarrhea, Vomit. Ingestion of fluid can lead to esophageal and gastric necrosis, circulatory collapse, and even death. Personnel exposed to hydrofluoric acid should be protected. When the skin is exposed to hydrofluoric acid, it should be immediately washed with a large amount of water, and in severe cases, it should be sent to the hospital for treatment. Attention should be paid to ventilation at the work site. Should be stored in a ventilated warehouse. Containers must be sealed and protected from direct sunlight. When metal can release hydrogen, Mars easily cause combustion or explosion, and therefore can not be mixed with metal powder, oxidant, alkali, organic matter and other storage.
pH indicator color change ph range | 1 |
LogP | 0.1 at 20℃ |
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
product description | hydrofluoric acid (HF for short) is an aqueous solution of hydrogen fluoride gas, also known as fluoric acid, white bone acid, bone-melting water, drilling water, rust remover and pickling. it is colorless and transparent to light yellow smoking liquid at normal temperature, has pungent smell, 0.98 specific gravity, slightly lighter than water, has a boiling point of 19.4 ℃, and is extremely volatile, if you put it in the air, you will send white smoke. An aqueous solution containing less than 60% hydrogen fluoride is a colorless and clear fuming liquid. Industrial products are usually aqueous solutions with HF content of 40 ~ 45%. It has a pungent odor, and generates fluorosulfonic acid with sulfur trioxide or chlorosulfonic acid, and reacts with halogenated aromatics, alcohols, alkenes, and hydrocarbons to generate fluorine-containing organic matter, which is dissolved in water to generate a highly corrosive acid, which is a medium-strength acid. It stinks and is extremely toxic. It is easy to ulcerate when touching the skin. Its degree is worse than any acid. If it is inhaled, it can be fatal, so strict attention must be paid when using it. 1. Hydrofluoric acid can also interact with general metals, metal oxides, and hydroxides to form various metal fluorides, but the effect is not as severe as hydrochloric acid. Gold, platinum, lead, paraffin and some plastics (polyethylene, etc.) do not work with it, so it can be used as a container. 2. It is extremely corrosive and can erode glass and silicate to generate gaseous silicon tetrafluoride. The reaction formula is as follows: SiO2 + 4HF → H2O + SiF4 ↑, glass is a compound of silicon, so hydrofluoric acid cannot be contained in a glass container. 3. Hydrofluoric acid can form acid salts. Hydrofluoric acid is a mono acid, but it can produce a series of acid salts such as NaHF2, KHF2, NH4HF2, etc., which are the other three hydrohalic acids. 4. The weak acidity of hydrofluoric acid, because of the relatively strong binding ability between hydrogen and fluorine atoms, makes hydrofluoric acid cannot be completely dissociated in water. Among the hydrohalic acids, only hydrofluoric acid is a weak acid (its ionization constant is 3.5x 10 ^-4, and its apparent ionization degree is 10% when the concentration is 0.1 mo1.L ^-1, so HF can also be barely counted as a medium Strong acid. The degree of ionization when concentrated is greater than when thin and different from general weak electrolytes). |
Health hazards | Hydrofluoric acid has irritating odor and severe toxicity. It is a moderately weak acid and is corrosive. It is often used to make fluorocarbons, Organic or inorganic fluorides such as sodium fluoride, aluminum fluoride, uranium hexafluoride and cryolite, used in stainless steel, non-ferrous metal pickling, semiconductor industry as cleaning agent, glass etching industry as etchant, steel industry as surface rust remover, petrochemicals industry as catalyst, cleaning service industry as dirt corrosion cleaning agent or exterior wall cleaning agent. For professionals who can be exposed to hydrofluoric acid in their daily work, improper use may cause harm to the human body. The exposure routes include skin and mucous membrane contact, respiratory tract inhalation and gastrointestinal intake. If the skin is exposed to a higher concentration of hydrofluoric acid above 50%, it will immediately cause pain, whitening, redness and swelling. Blisters will be produced within 1 to 2 hours, and necrosis and ulceration will occur within 6 to 24 hours, if you are exposed to a lower concentration below the 10%, symptoms such as pain often occur within 6 hours or more, so they are often ignored by the person concerned and treated too late, resulting in permanent damage. Generally, the most common injured part is the finger. In addition, if exposed from the respiratory tract, gastrointestinal tract and other ways, it will produce symptoms such as cough, burning sensation and dyspnea, or cause abdominal pain, nausea, vomiting blood, intestinal perforation and other symptoms. The harm of hydrofluoric acid to the human body, in addition to acid corrosion damage, the fluoride ions entering the human body may combine with calcium and magnesium ions, resulting in low blood calcium, low blood magnesium and high blood potassium, which in turn affects the nerves and cardiovascular system. Daily use of hydrofluoric acid should avoid contact with the body, including skin, eyes and respiratory tract, etc., to prevent skin contact, wear fluorinated polyethylene (PVDF), natural rubber and other materials of gloves is preferred, do not use cloth and cotton gloves, and in easy splash occasions should be full-body protection, can use rubber material one-piece protective clothing, work boots, eye goggles or full-scale mask. If you are accidentally corroded by hydrofluoric acid, you should use a large amount of water to wash the affected area for at least 30 minutes as soon as possible, until you can't see any attached solid or liquid on your body, and send it to the doctor as soon as possible. You should bring the chemicals you are in contact with to provide medical staff for timely and correct diagnosis and treatment. |
Toxicity | See hydrofluoric acid. Hydrofluoric acid is extremely corrosive, can corrode glass and nails, and is extremely toxic. The maximum allowable concentration is 1 mg/m3(LD50 1.276 × 10-3). Skin contact causes redness and burning sensation, and blurred vision will appear in eyes. After inhalation, there are sore throat, cough, dyspnea, abdominal pain, diarrhea and vomiting when entering the digestive tract. Attention should be paid to ventilation during protection. Operators must wear protective equipment to prevent touching the skin. If you touch the skin by mistake, you should immediately rinse with a large amount of water. After rinsing the acid, you can generally apply the affected area with mercuric solution or gentian violet solution. Should be sent to hospital for treatment in serious cases. It is irritating and toxic, has a strong corrosive effect on the skin and eyes, and can produce severe burns. The burns are not displayed immediately, and the treatment is slow. It must be taken in a well-ventilated place or in a fume hood. Wear fluorine-resistant gloves, boots, protective rubber aprons and masks of appropriate size. In case of contact or suspected contact with this product, rinse with plenty of water and treat it immediately. |
Use | Mainly used as a raw material for fluorine-containing compounds, also used in the manufacture of aluminum fluoride and cryolite, semiconductor surface etching and used as alkylation Catalyst Used as a strong acidic etchant in the electronics industry, it can be used in conjunction with nitric acid, acetic acid, ammonia, and hydrogen peroxide. Used as an analytical reagent and also used in the preparation of high-purity fluorides It is a source of fluorine necessary for fluorine salts, fluorine refrigerants, fluoroplastics, fluorine rubbers, fluorine medicines and pesticides It is a raw material for the production of refrigerants "Freon", fluorine-containing resins, organic fluorides and fluorine. It can be used as a catalyst for organic synthesis such as alkylation, polymerization, condensation, and isomerization in chemical production. It is also used to corrode strata when mining certain deposits, as well as the extraction of rare earth elements and radioactive elements. In the atomic energy industry and nuclear weapons production, it is the raw material for the manufacture of uranium hexafluoride, as well as the raw material for the production of rocket fuel and additives. It can also be used to corrode glass and impregnate wood. Used in the manufacture of organic or inorganic fluorides, such as fluorocarbons, sodium fluoride, aluminum fluoride, uranium hexafluoride and cryolite. Also used for stainless steel, non-ferrous metal pickling, glass meter scale, glassware and mirror engraving, lettering, as well as glassware polishing, frosted bulb and general bulb treatment, metal graphite emulsion silicon purification, metal casting sand removal, graphite ash removal, semiconductor (germanium, silicon) manufacturing. It is also used for dye synthesis. and other catalysts for organic synthesis. It is also used in electroplating, reagents, fermentation, ceramic treatment, and the manufacture of fluorine-containing resins and flame retardants. Used for etching glass, pickling metal, making inorganic fluoride salt products and chemical reagents. Used in the atomic energy industry, making elemental fluorine and fluoride, and can also be used as a catalyst, fluorinating agent, etc. for the manufacture of organic or inorganic fluorides, and also used for stainless steel, non-ferrous metal pickling, glassware frosting and pickling, The treatment of frosted bulbs, etc. Determination of silica, manufacture of fluorides, copper cleaners, metallurgical metallographic analysis, silicon compound analysis. |
production method | sulfuric acid method mixes dried fluorite powder and sulfuric acid according to the ratio of 1:(1.2~1.3) and sends them to a rotary reactor for reaction. the gas phase temperature in the furnace is controlled at 280 ℃ 10 ℃. After the reaction, the gas enters the crude distillation tower to remove most of the sulfuric acid, water and fluorite powder. The temperature of the tower kettle is controlled at 100~110 ℃, and the top temperature is 35~40 ℃. The crude hydrogen fluoride gas is condensed into liquid state by degassing tower. The temperature of tower kettle is controlled at 20~23 ℃, and the top temperature is -8 ℃ 1 ℃. Then it enters the rectification tower for rectification. The temperature of tower kettle is controlled at 30~40 ℃, and the top temperature is 19.6 ℃ 0.5 ℃. The refined hydrogen fluoride is absorbed with water to obtain hydrofluoric acid products. Its CaF2 H2SO4 → 2HF CaSO4 The hydrogen fluoride generated by the decomposition of fluorite by sulfuric acid is crude distillation, degassing, and then rectified to obtain anhydrous hydrofluoric acid. Its CaF2 H2SO4 → 2HF CaSO4 refining and purification method purified industrial grade hydrofluoric acid by distillation, condensed and separated to remove impurities, and filtered by microporous filter membrane to remove dust particles to produce colorless and transparent electronic grade hydrofluoric acid. |
category | harmful gases |
toxicity classification | highly toxic |
acute toxicity | inhalation-rat LC50: 1276 PPM/1 hour; Inhalation-mouse LC50: 342 PPM/1 hour |
stimulation data | eye-human 50 mg severe |
explosive hazard characteristics | steel cylinders can explode when heated and exposed to the sun; leakage emits highly toxic smoke |
flammability hazard characteristics | highly corrosive hydrofluoric acid is generated when exposed to water; combustion produces toxic fluoride smoke |
storage and transportation characteristics | warehouse ventilation and low temperature drying; Stored separately from h-porogen, alkali, cyanide and metal powder |
fire extinguishing agent | mist water, sand |
occupational standard | TWA 3 PPM (2 mg/m3); STEL 3 PPM (fluorine) |
DOT Classification | 8, Hazard Zone C (Corrosive material) |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
immediate life-threatening and health concentration | 30 ppm |