Name of aqueous solution: hydrogen peroxide
English name: hydrogen peroxide
Alborn
hydrogen peroxide
CAS number: 7722-84- 1
EINECS login number: 23 1-765-0.
Directory [hidden]
molecule
Physical and chemical characteristics
Fluorescence reaction
Cell reaction
Main applications
health hazard
Dangerous characteristics
What is the function of hydrogen peroxide?
Often used by illegal businessmen
Factors affecting hydrogen peroxide bleaching
Industrial preparation method of hydrogen peroxide 1
Industrial preparation method of hydrogen peroxide II
Industrial preparation method of hydrogen peroxide-Trimolecular
Physical and chemical characteristics
Fluorescence reaction
Cell reaction
Main applications
health hazard
Dangerous characteristics
What is the function of hydrogen peroxide?
Often used by unscrupulous traders, the factors affecting hydrogen peroxide bleaching-industrial hydrogen peroxide method-industrial hydrogen peroxide method-industrial hydrogen peroxide method-industrial hydrogen peroxide method.
[Edit this paragraph] Molecules
Molecular formula: H2O2
Molecular structure: O atoms are bound by sp3 hybrid orbitals, and the molecules are polar molecules with valence of * * *.
Relative molecular weight: 34.0 1
[Edit this paragraph] Physical and chemical characteristics
Appearance and properties: the aqueous solution is colorless and transparent, with a faint special smell. Pure hydrogen peroxide is a light blue oily liquid.
Main ingredients: industrial grade is 27.5% and 35%. Melting point (℃):-0.89℃ (anhydrous)
Boiling point (℃): 152. 1℃ (anhydrous)
Refractive index: 1.4067(25℃)
Relative density (water = 1): 1.46 (anhydrous)
Saturated vapor pressure (kpa): 0. 13 (15.3℃)
Solubility: It can be mixed with water, ethanol or ether in any proportion. Insoluble in benzene and petroleum ether.
Structure: H-O-O-H has no chirality. Because O in -O-O- is not the lowest oxidation state, it is unstable and easy to break.
The solution contains hydrogen ions, and peroxide will generate hydroxide ions under the action of hydrogen ions, in which the concentration of hydrogen ions is greater than that of hydroxide ions.
Toxicity LD50 (mg/kg): 700 under the skin of rats.
Danger of explosion: this product is combustion-supporting and has strong irritation.
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 strip with Mars into the test tube, and the wooden strip will be rekindled.
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. Manganese dioxide as a catalyst reacts with hydrogen peroxide to produce oxygen and water.
[Edit this paragraph] Fluorescence reaction
Chlorine is introduced into the alkaline solution of H2O2, in which a large number of hydroxyl ions inhibit the concentration of hydrogen ions, making it possible to have a large number of peroxide ions in the solution. Under the action of chlorine, -O-O- is oxidized to singlet oxygen, so it emits red fluorescence.
According to Zhang Zhihao's experiment in Xishi Middle School, the PH value of the reaction is roughly 7.2-7.8, which is for reference only.
[Edit this paragraph] Electrolytic reaction
Electrolysis of hydrogen peroxide will produce ozone and water, while water will produce hydrogen and oxygen. Electrolytic hydrogen peroxide solution
The color of ozone produced for the first time is orange.
[Edit this paragraph] Main purpose
There will be oxidation or reduction under different conditions. It can be used as oxidant, bleaching agent, disinfectant and dechlorination agent, and can be used for rocket fuel, organic or inorganic peroxide, foam plastic and other porous substances.
Medical hydrogen peroxide (about 3% or less) is a good disinfectant.
Industrial use is about 10% for bleaching, as strong oxidant, dechlorination agent, fuel, etc.
This experiment was used as the raw material for making O2.
[Edit this paragraph] Health hazards
The most important hazards and impacts:
Acute:
Inhalation: Steam can irritate eyes, nose and throat.
Skin contact: it will cause tingling and temporary whitening, and it will recover after washing for 2-3 hours, which will cause redness and blistering.
Eye contact: the possibility of serious injury and blindness. It may take a week or more for this symptom to appear.
If swallowed, it will hurt the stomach and throat, and may lead to esophageal and gastric bleeding.
Chronic:
Inhalation: Causes chronic respiratory diseases.
Skin contact: causes skin diseases.
Eye contact: causes eye diseases.
Main symptoms: irritation, skin tingling, temporary whitening, redness, blistering, eye diseases and stomach bleeding. When it is corrosive injury, it can lead to blindness, tissue necrosis and pulmonary edema in severe cases.
[Edit this paragraph] 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 oxygen, 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 iron, 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. Hydrogen peroxide with concentration over 74% can cause gas phase explosion in a closed container with proper ignition source or temperature.
Emergency treatment: quickly evacuate the personnel in the leaked and polluted area to a safe area, isolate them, and strictly restrict access. It is recommended that emergency personnel wear self-contained positive pressure breathing apparatus and protective clothing. Cut off the leakage source as much as possible. Prevent it from flowing into 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 leaks: damming or digging holes to contain them. 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 recycle it or transport it to a waste disposal site for treatment.
[Edit this paragraph] What is the function of hydrogen peroxide?
Hydrogen peroxide is a liquid with two hydrogen atoms and two oxygen atoms in each molecule, which has strong permeability and oxidation. Hydrogen peroxide is commonly used in medicine to clean wounds and locally resist bacteria. The latest research shows that hydrogen peroxide is not only a medical product, but also an excellent beauty product.
Facial skin is in direct contact with the external environment and is often polluted by bacteria and dust. In addition, the dirt formed by sweat glands and sebaceous glands of the skin itself can easily induce acne, dermatitis, boils and other diseases, thus affecting the beauty of the skin. Applying hydrogen peroxide to the skin can not only remove the dirt on the skin, but also directly enhance the activity of surface cells, inhibit and oxidize the deposition of melanin, and make the skin delicate and elastic. Operation method: After washing your face with facial cleanser, apply a towel to your face with 3% hydrogen peroxide for 5 minutes each time, 1 time every day, and 10 day is a course of treatment. Pay attention to avoid hydrogen peroxide entering eyes during operation.
If you use hydrogen peroxide for beauty, you must ask the dermatologist for advice in advance. It is quite dangerous to whiten directly with hydrogen peroxide. Although it will make the skin white in a short time, it will cause strong irritation to the skin after a long time, which may seriously burn the epidermis and make the skin rough and blister.
In addition, hydrogen peroxide can also brighten hair color. For women with long hair, it can be directly applied to the skin twice a day after hair removal, so that the hair that grows later will not turn black and thick, but will become soft and yellow.
Hydrogen peroxide used to be one of the components of the second hair dye (oxidant), but it was harmful to human body, so it has been eliminated.
In addition, in the laboratory, hydrogen peroxide and manganese dioxide are often mixed to produce oxygen.
Chemical equation of oxygen production by hydrogen peroxide;
2H2O2=MnO2=2H2O+O2↑
[Edit this paragraph] is often used by illegal traders.
Hydrogen peroxide, commonly known as hydrogen peroxide, is a colorless and tasteless liquid. When added to food, it can decompose and release oxygen, and has the functions of bleaching, antisepsis and deodorization. Therefore, some businesses prohibit soaking hydrogen peroxide in the production process of some foods that need whitening, such as beef tenderloin and jellyfish, shark's fin, shrimp, hairtail, squid, canned fruit, flour products, etc., to improve the appearance of products. A few food processing units soak and bleach moldy dry aquatic products in hydrogen peroxide and then resell them, or to eliminate the blackness, congestion and mildew spots on the surfaces of dead chickens, ducks or pigs, soak and bleach these raw materials in high concentration hydrogen peroxide, and then add artificial pigments or nitrite for sale. Hydrogen peroxide can cause cancer by forming epoxide with starch in food, especially digestive tract cancer. In addition, industrial hydrogen peroxide contains toxic and harmful substances such as arsenic and heavy metals, which seriously harms consumers' health. According to its toxicity test report, FAO (Food and Agriculture Organization of the United Nations) and WHO (World Health Organization of the United Nations) stipulate that hydrogen peroxide is only used as an emergency measure to preserve milk. China's "Hygienic Standard for the Use of Food Additives" also stipulates that hydrogen peroxide can only be used in milk in limited quantities, and only in Inner Mongolia and Heilongjiang, and there must be no residue in other foods.
[Edit this paragraph] Factors affecting hydrogen peroxide bleaching
Factors such as concentration, temperature, time and PH value are the main conditions of chemical reaction. In the process of hydrogen peroxide bleaching, the relationship between these factors should be clarified in order to formulate a reasonable process.
1, concentration
The reasonable concentration of hydrogen peroxide bleaching should be based on the principle that it can not only achieve a certain whiteness and remove cottonseed hulls, but also minimize fiber damage. Practice has proved that the relationship between fabric whiteness and hydrogen peroxide concentration is not directly proportional. When the steaming process is adopted, the concentration is controlled at 3-5g/L, which can meet certain whiteness requirements. The higher the concentration is, the whiteness does not increase much, but it is easy to damage the fiber. Therefore, the concentration of steaming process is generally 3-5g/L, and the thin fabric is lower. The specific determination depends on the equipment used, bleaching method, fabric thickness, desizing and scouring conditions and bath ratio. In order to reduce the damage to the fiber as much as possible, the concentration should be low, and measures should be taken during scouring to obtain higher whiteness.
2. Temperature
Temperature is directly related to the decomposition rate of hydrogen peroxide. Under the condition of certain concentration and time, the decomposition consumption of hydrogen peroxide on fabric increases with the increase of temperature, so the bleaching effect of fabric increases with the increase of decomposition rate of hydrogen peroxide on fabric. When the temperature reaches 90- 100℃, hydrogen peroxide can be decomposed by 90%, and the whiteness is the best. But when the temperature is 60%, the decomposition rate is only about 50%.
3. Time
The determination of hydrogen peroxide bleaching time is related to temperature. If the cold bleaching method is adopted, it will be stacked at room temperature for about 10h, but the high-temperature steaming bleaching time can be greatly shortened. From the consumption rate of hydrogen peroxide, the consumption rate has reached 70% after steaming 15min, and reached 90% after steaming for 45-60 min, and tends to be balanced. It can be seen that the steaming time of 45-60 min is enough.
4. Alkaline reagent
In conventional bleaching, the PH value of bleaching solution is 10.5~ 1 1, but adding water glass can't meet the requirements. Therefore, alkaline reagents are needed to adjust the PH value. The most commonly used alkaline agent is caustic soda, the dosage of which is1-2g/L. It is an activator, which can promote the decomposition of hydrogen peroxide to generate hydrogen peroxide ions and has bleaching effect. Under the condition of PH value of 10.5~ 1 1, hydrogen peroxide decomposes at a medium speed to achieve the purpose of bleaching. However, in the short process of desizing and scouring and bleaching, the dosage of caustic soda is high, and caustic soda not only adjusts the PH value, but also has the functions of desizing and scouring and bleaching. This makes the bleaching bath unstable and accelerates the decomposition of hydrogen peroxide, which not only wastes hydrogen peroxide, but also may lead to fiber degradation and brittle damage of fabrics. In order to control the decomposition rate of hydrogen peroxide, as mentioned above, suitable stabilizers should be added to decompose hydrogen peroxide according to the process requirements, and the balance between decomposition and stability should be achieved. This is the "controlled hydrogen peroxide bleaching process" with the help of stabilizers. This process can not only achieve better fabric whiteness and impurity removal effect, but also cause great damage to fibers.
[Edit this paragraph] Industrial preparation method of hydrogen peroxide 1
Air electrode for producing alkaline hydrogen peroxide and preparation method thereof
The invention belongs to the field of preparing inorganic compounds by electrochemical methods. The invention relates to a quinone-containing air electrode for industrial preparation of alkaline hydrogen peroxide and a preparation method thereof. The multi-component electrode group of the invention is assembled by unit polar plates, each pair of electrodes consists of a cathode plate, an air cathode carbon core containing quinone, an ion exchange diaphragm, a plastic support net and an anode plate, the upper and lower ends of an electrode working area are provided with a fluid distribution chamber and a collection chamber, the fluid inlet is provided with a throttling hole, and the multi-component electrodes are connected in series through a limited dipole, so that the plastic hose of the anode for circulating alkaline water is extended to more than 5 meters. According to the invention, alkaline hydrogen peroxide can be prepared under the condition of directly using low-pressure air, and satisfactory working indexes are obtained, and the defect that the electrode is saturated with alkaline water and fails does not exist.
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.
[Edit this paragraph] Industrial preparation method of hydrogen peroxide II
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. Neutralize the aqueous solution of sodium peroxide to pH 9.0-9.7 with phosphoric acid or sodium dihydrogen phosphate to generate Na-[2] HPO-[4] and H-[2] O-[2], and cool the aqueous solutions of Na-[2] HPO-[4] and H-[2] O-[2] to +5-. Most of Na-[2] HPO-[4] precipitates in the form of Na-[2] HPO-[4] 10h-[2] O hydrate, and then Na-[2] HPO-[4] 10h-[2] O is hydrated in the centrifugal separator. basis
-
Claim:
A method for preparing hydrogen peroxide is characterized by comprising the following steps: (1) neutralizing sodium peroxide aqueous solution to 9.0-9.7 with phosphoric acid or sodium dihydrogen phosphate (nah2po4) to generate Na2HPO4 and H2O. (2) cooling the aqueous solution of Na2HPO4 and H2O2 to +5-5℃, so that most of Na2HPO4 is replaced by Na2HPO4.65438+. (3) separating the mixture containing Na2HPO4. 10h2o hydrate and hydrogen peroxide aqueous solution are separated in an eccentric separator to generate Na2HPO4. 10h2o crystal can be separated from a mixture containing a small amount of N2. (4) the aqueous solution of hydrogen peroxide containing a small amount of Na2HPO4 is evaporated in an evaporator to obtain H2O2 and H2O2-containing steam, and the Na2HPO4 concentrated salt solution containing hydrogen peroxide flows out from the bottom and returns to the neutralization tank; (4)
[Edit this paragraph] Industrial preparation method of hydrogen peroxide III
Hydrogen peroxide with a concentration of 95% can be obtained by electrolyzing 60% sulfuric acid and then hydrolyzing it.
-
Packing: Packed in polyethylene drums with vent holes on the container cover, and packed in wooden cases, each with a net weight of 20kg.
Precautions for storage and transportation: it belongs to the first-class inorganic acid corrosive product. This product should be stored in a cool, clean and ventilated warehouse. The temperature of the warehouse shall not exceed 30℃ to avoid sunlight. The container should be tightly covered, but the ventilation holes should be unblocked to prevent dust from blocking, and the dust can easily decompose and deteriorate. Keep away from heat sources and kindling, and do not mix with organic matter or metals such as iron, copper and chromium and their salts. Wear work clothes, masks and gloves when handling. If contact with skin by mistake, rinse with water, if contact with eyes, rinse with warm water. This product should not be stored for a long time, so the inspection should be strengthened at ordinary times, and the leaking barrel should be replaced in time. If smoke is found on the stow-wood, the smoking stow-wood should be removed from the warehouse immediately or put out with water.
Fire can be put out with water, sand or carbon dioxide fire extinguishers.