Molecular structure: O atoms are bound by sp3 hybrid orbitals, and the molecules are polar molecules with valence of * * *. The H-O-O bond angle is 96 degrees and 52 minutes. Appearance and properties: the aqueous solution is a colorless and transparent liquid with a weak special smell. Pure hydrogen peroxide is a light blue oily liquid. Main ingredients: industrial grade is 27.5% and 35%. Reagent grades are often divided into 30% and 40%. Molecular weight: 34.02 melting point (℃):-0.89℃ (anhydrous) boiling point (℃): 152. 1℃ (anhydrous) refractive index: 1.4067(25℃) relative density (water =/kloc- Insoluble in benzene and petroleum ether. Structure: H-O-O-H has polar and nonpolar valence bonds. Toxicity LD50 (mg/kg): 700 mg/kg by subcutaneous injection in rats [4].
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acid-base
H2O2 is a binary weak acid with acidity. [5]
oxidizability
H2O 2+2ki+2hcl = = 2kcl+I2+2h2o 2fe2+H2O2+2h+= = 2fe3+2h2o 2+H2S = = s↓+2h2o 2+SO2 = = H2SO4 Note: The reduction product of H2O2 is H2O under acidic conditions. [5]
reducing power
2kmno4+5h2o2+3H2SO4 = = 2mnso4+k2so4+5o2 ↑+8h22kmno4+3h2o2 = = 2mno2+2koh2o2 ↑+2h2o2o2+Cl2 = = = = 2hcl+O2 Note: the oxidation product of H2O2 is O2[5].
unstable
Hydrogen peroxide can be decomposed into oxygen and water at room temperature (slow decomposition), and the reaction can be accelerated after heating or adding catalysts, such as manganese dioxide, copper sulfate, hydrogen iodide, lead dioxide, ferric chloride, catalase in organisms, etc. 2h2o 2 = = MnO 2 = = 2h2o 2+O2↑2h2o 2 = =δ= = 2h2o 2+O2↑4、H2O2。 5.H2O2 can be used as disinfectant, bactericide, bleaching agent and dechlorination agent, and pure H2O2 can also be used as oxidant for rocket combustion. [5]
Cell reaction
Electrolysis of hydrogen peroxide will produce ozone and water, and water will produce hydrogen and oxygen. Chemical equation of step-by-step reaction: 1. 3H2O2== electrolysis == 3H2O+O3↑ II. 2H2O == electrolysis == 2H2↑+O2↑ The total reaction chemical equation is: 6H2O2== electrolysis ==6H2↑+2O3↑+3O2↑ Note: the color of the first ozone is orange. [5]
decomposition reaction
1. Take 5ml5% of 5% hydrogen peroxide solution in the test tube, and put the wooden strips with Mars into the test tube, so that the wooden strips will not re-ignite. 2. Take 5ml5% of 5% 5% hydrogen peroxide solution in the test tube, heat it, and then put the wooden strips with Mars into the test tube, so that it is difficult for the wooden strips to re-ignite. Note: At this time, there is not much water vapor in the test tube, but the oxygen concentration is low. 3. Take 5ml5% of 5% 5% hydrogen peroxide solution in the test tube, add a small amount of manganese dioxide, and then put the wooden strip with Mars into the test tube, and the wooden strip will be rekindled. As a catalyst, manganese dioxide reacts with hydrogen peroxide to generate oxygen and water. 4. chemical equation: 2h2o2 = = MnO2 = = 2h2o+O2 < 5 >
Catalytic principle
The decomposition of hydrogen peroxide is an autoredox reaction, also known as disproportionation reaction. Comparison of standard electrode potential in acidic solution: O2+2h++2e-= H2O2 0.695v H2O2+2h+2e-= 2h2o1.776V. It can be seen that hydrogen peroxide has strong reducibility and strong oxidation, and the electrode potential of disproportionation reaction is as high as 1.0V, so the disproportionation reaction should be quite intense, but due to certain over-oxidation, When manganese dioxide is used as catalyst, the most recognized reaction principle at present is: H2O2+MnO2 = H2MnO4 (δ h
Edit the function and purpose of this paragraph.
Chemical industry is used as raw materials for producing sodium perborate, sodium percarbonate, peracetic acid, sodium chlorite and thiourea peroxide. , and as an oxidant of tartaric acid and vitamins. The pharmaceutical industry is used as bactericide, disinfectant and oxidant to produce thiram insecticide and 40l antibacterial agent. Printing and dyeing industry is used as bleaching agent for cotton fabric and color developer after dyeing with vat dyes. Used to remove iron and other heavy metals when producing metal salts or other compounds. It is also used in electroplating solution, which can remove inorganic impurities and improve the quality of plated parts. It is also used to bleach wool, raw silk, fur, feathers, ivory, bristles, pulp and fat. High concentration hydrogen peroxide can be used as rocket power fuel. [6]
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health hazard
Invasion route: inhalation and ingestion. Health hazard: Inhalation of vapor or fog of this product has a strong stimulating effect on respiratory tract. Direct contact with liquid can lead to irreversible damage and even blindness. Oral poisoning can cause abdominal pain, chest pain, dyspnea, vomiting, temporary motor and sensory disorders and elevated body temperature. Individual cases have visual impairment, epileptic spasm and paraplegia. [7]
Toxicological data
Acute toxicity: LD504060mg/kg (rat percutaneous); LC502000mg/m3, 4 hours (inhaled by rats) mutagenicity: microbial mutagenicity: Salmonella typhimurium 10μL/ dish; Escherichia coli 5ppm. Sister chromatid exchange: hamster lung 353 μ mol/L. Carcinogenicity: IARC Carcinogenicity review: animal suspected positive. Hazard characteristics: explosive strong oxidant. Hydrogen peroxide itself does not burn, but it can react with combustible substances to release a lot of heat and atmosphere, causing fires and explosions. Hydrogen peroxide is most stable at pH 3.5 ~ 4.5, easily decomposed in alkaline solution, and can also be decomposed under strong light, especially short-wave radiation. When heated to above 100℃, it began to decompose rapidly. It forms an explosive mixture with sugar, starch, alcohol, petroleum products and other organic substances, which can explode under the action of impact, heat or electric spark. When hydrogen peroxide comes into contact with many inorganic compounds or impurities, it will decompose rapidly and lead to explosion, releasing a lot of heat, oxygen and water vapor. Most heavy metals (such as terbium, copper, silver, lead, mercury, zinc, cobalt, nickel, chromium, manganese, etc. ) and its oxides and salts are active catalysts, and dust, cigarette ash, carbon powder and rust can also accelerate decomposition. When the concentration of hydrogen peroxide exceeds 74%, gas explosion will occur in a closed container with proper ignition source or temperature. Combustion (decomposition) products: oxygen, water. [7]
Emergency treatment of leakage
Evacuate the leaked and polluted personnel to a safe area quickly, isolate them and strictly restrict access. It is recommended that emergency personnel wear self-contained positive pressure breathing apparatus and acid-proof overalls. Cut off the source of leakage as much as possible to prevent it from entering confined spaces such as sewers and flood discharge ditches. Small amount of leakage: absorbed by sand, vermiculite or other inert substances. It can also be washed with plenty of water, diluted and put into the wastewater system. A large number of water leaks: build a dike or dig a pit to accommodate; Spray water to cool and dilute steam, protect field personnel, and dilute the leakage into nonflammable substances. Pump it into a tanker or a special collector, and then recycle it or send it home to a waste disposal site for treatment. Waste treatment method: the waste liquid is diluted with water and decomposed to release oxygen. After the waste liquid is fully decomposed, it is flushed into the sewer. [7]
protective measure
Respiratory protection: When you may come into contact with its vapor, you should wear a self-priming filter gas mask (full face mask). Eye protection: respiratory protection has been done. Physical protection: Wear polyethylene gas protective clothing. Hand protection: wear neoprene gloves. Others: Smoking is strictly prohibited in the workplace. After work, take a shower and change clothes. Pay attention to personal hygiene. [7]
Emergency treatment
Skin contact: take off contaminated clothes and rinse with plenty of running water. Eye contact: lift the eyelid immediately and rinse it thoroughly with plenty of flowing water or normal saline for at least 15 minutes. See a doctor. Inhalation: leave the scene quickly and go to a place with fresh air. Keep the respiratory tract unobstructed. If you have difficulty breathing, give oxygen. If breathing stops, give artificial respiration immediately. See a doctor. Ingestion: Drink plenty of warm water, induce vomiting and seek medical advice. Fire extinguishing method: Firefighters must wear full-body fire-proof and gas-proof clothing. Move the container from the fire to an empty place as much as possible. Spray water to cool the burning container until the fire goes out. If the container in the fire changes color or the safety pressure relief device sounds, it must be evacuated immediately. Extinguishing agent: water, mist water, dry powder, sand. [7]
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Air electrode for producing alkaline hydrogen peroxide and preparation method thereof
A quinone-containing air electrode for producing alkaline hydrogen peroxide is characterized in that each pair of electrodes consists of an anode plate, a plastic net, a cation diaphragm and a quinone-containing air cathode; The upper and lower ends of the electrode working area are provided with a distribution chamber for fluid to enter and a collection chamber for fluid to discharge; The fluid inlet is provided with a throttle hole; Multi-component electrodes are connected in series through limited dipoles; The plastic hose for circulating alkaline water at the anode inlet and outlet is lengthened and then connected to the liquid collecting main pipe; The multi-component electrode group is assembled by unit plates. [8]
Neutralizing sodium peroxide aqueous solution with phosphoric acid
The invention relate to that field of preparation of inorganic compounds, in particular to a method for prepare hydrogen peroxide from a cathode product sodium peroxide aqueous solution obtained in a patent application with the application number of 87 1 03988. Neutralizing the aqueous solution of sodium peroxide to pH 9.0-9.7 with phosphoric acid or sodium dihydrogen phosphate to generate Na2HPO4 and H2O2, cooling the aqueous solution of Na2HPO4 and H2O2 to +5-5℃, and precipitating most of Na2HPO4 in the form of Na2HPO410H2O hydrate. Then the mixture containing na 2 hpo 4 1 H2O2 hydrate and aqueous hydrogen peroxide solution is separated in a centrifugal separator to separate the hydrate, and then the aqueous hydrogen peroxide solution containing a small amount of Na2HPO4 is evaporated. Claim: A method for preparing hydrogen peroxide is characterized in that it is prepared from aqueous sodium peroxide solution by the following steps: (1) neutralizing the aqueous sodium peroxide solution with phosphoric acid or sodium dihydrogen phosphate NaH2PO4 to 9. (2) cooling the aqueous solution of Na2HPO4 and H2O2 to +5 ~-5℃, so that most of Na2HPO4 can be precipitated in the form of Na2HPO410h2o hydrate. (3) separating the mixture containing na 2 hpo 410H2O hydrate and aqueous hydrogen peroxide solution in an eccentric separator, thereby separating Na2HPO410H2O crystals from aqueous hydrogen peroxide solution containing a small amount of Na2HPO4. (4) The aqueous solution of hydrogen peroxide containing a small amount of Na2HPO4 is evaporated in the evaporator to obtain steam containing H2O2 and H2O, and the concentrated salt solution of Na2HPO4 containing hydrogen peroxide flows out from the bottom and returns to the neutralization tank. (5) Fractionating the steam containing H2O2 and H2O in a fractionator under reduced pressure to obtain about 30% H2O2 product. [8]
Electrolytic sulfuric acid method
Hydrogen peroxide with a concentration of 95% can be obtained by electrolyzing 60% sulfuric acid and then hydrolyzing it. [8]
2- ethyl anthraquinone process
At present, the main method of industrial scale production is 2-ethylanthraquinone (EAQ). 2-ethylanthraquinone reacts with hydrogen at a certain temperature and pressure to generate 2- ethyl hydroanthraquinone, and 2- ethyl hydroanthraquinone reacts with oxygen at a certain temperature and pressure to be reduced to generate 2-ethylanthraquinone and hydrogen peroxide. [8]