Let me explain to you the mercaptans that are difficult to remove in the production of methanol!

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　National Standard No. 31034 CAS No. 75-08-1 Chinese name: ethyl mercaptan English name: ethyl mercaptan； ethanethiol also known as ethane sulfide ； Mercaptoethane molecular formula C2H6S ； CH3CH2SH Appearance and properties Colorless liquid with strong garlic smell Molecular weight 62.13 Vapor pressure 53.32kPa/17.7℃ Flash point: -45℃ melting point-147℃ boiling point: 36.2℃ Solubility Slightly soluble in water, deeper than most organic solvents such as ethanol and ether Density Relative density (water = 1) 0.84 ； Relative density (air = 1) 2.14 Stability Stability hazard mark 7 (low flash point flammable liquid) Mainly used as a stabilizer for adhesives and an intermediate for chemical synthesis 2. Impact on the environment: 1. Health hazards Invasion routes: Inhalation, ingestion, transdermal absorption. 　　health hazards: This product mainly acts on the central nervous system. Inhaling low concentration vapor can cause headaches and nausea ； appear in higher concentrations * * effect. High concentrations can cause respiratory paralysis and death. Poisoned persons may experience vomiting, diarrhea, and protein, casts, and hematuria in the urine. 　　2. Toxicological information and environmental behavior acute toxicity: LD50682mg/kg (rat oral) ； LC5011227mg/m3, 4 hours (rat inhalation) Hazardous characteristics: Its vapor and air can form explosive mixtures. It is easy to burn and explode when exposed to open flames or high heat. Reacts violently on contact with oxidizing agents. Contact with acids and acid mist produces toxic gases. Reacts with water and water vapor to release toxic or flammable gases. Reacts violently with calcium hypochlorite and calcium hydroxide. Its vapor is heavier than air and can spread to a considerable distance from a lower place. It will cause backfire when exposed to an open flame. If exposed to high heat, the internal pressure of the container will increase and there is a risk of cracking and explosion. 　　Combustion (decomposition) products: Carbon monoxide, carbon dioxide, sulfur oxides. 　　3. On-site emergency monitoring method: Portable gas chromatography 4. Laboratory monitoring method: Gas chromatography "Method for the Determination of Hazardous Substances in the Air" (Second Edition), compiled by Hang Shiping p-dimethylaminoaniline colorimetric method "Method for the Determination of Hazardous Substances in the Air" (Second Edition), compiled by Hang Shiping 5. Environmental standards: The maximum allowable concentration of harmful substances in the air in the workshop of the former Soviet Union is 1mg/m3 6. Emergency treatment and disposal methods: 1. Emergency response to leakage: Quickly evacuate personnel from the leakage contaminated area to a safe area, isolate them, and strictly restrict access. Cut off the fire source. It is recommended that emergency responders wear self-contained positive pressure breathing apparatus and fire protective clothing. Cut off the source of the leak as much as possible. Prevent entry into restricted spaces such as sewers and flood ditches. small leak: Absorb with activated carbon or other inert material. You can also rinse with large amounts of water, dilute the wash water and put it into the wastewater system. massive leaks: Build dikes or dig pits for containment ； Cover with foam to reduce vapor hazards. Use an explosion-proof pump to transfer it to a tanker or a special collector, and recycle or transport it to a waste treatment site for disposal. 　　Waste disposal methods: Use incineration method. The gas discharged from the incinerator must be washed with alkaline solution. 　　2. Protective Measures Respiratory System Protection: When the concentration in the air exceeds the standard, a self-priming filter gas mask (half mask) should be worn. When necessary, it is recommended to wear an air respirator. 　　eye protection: Wear chemical safety glasses. 　　body protection: Wear anti-static work clothes. 　　hand protection: Wear rubber gloves. 　　other: Smoking is strictly prohibited on the work site. After work, shower and change clothes. Pay attention to personal hygiene. 　　3. First aid measures Skin contact: Take off contaminated clothing and wash skin thoroughly with soap and water. 　　eye contact: Lift your eyelids and rinse with running water or saline. Seek medical attention. 　　inhalation: Leave the scene quickly and get to fresh air. Keep your airway open. If breathing is difficult, give oxygen. If breathing stops, perform artificial respiration immediately. Seek medical attention. 　　ingest: Drink enough warm water, induce vomiting, and seek medical attention. 　　Fire extinguishing methods: Move containers away from the fire to an open area if possible. Spray water to keep the fire container cool until the fire is extinguished. Containers in a fire scene must be evacuated immediately if they change color or if there is sound from the safety pressure relief device. fire extinguishing agent: Resistant foam, dry powder, carbon dioxide, sand. Water is ineffective in extinguishing the fire. 　　Hydrogen sulfide group or mercapto group-SH is an organic compound connected to an aliphatic hydrocarbon group. Organic compounds in which the mercapto group is directly connected to the aromatic core are called thiophenols. Exists in crude petroleum, usually various mercaptans based on ethyl mercaptan. In addition, allylthiol is present in mustard oil, and thiol-containing amino acids and cysteine ​​are present in proteins. The properties of mercaptans and thiophenols are similar to alcohols and phenols. Both mercaptans and thiols have a strong odor. When the concentration of ethyl mercaptan in the air reaches one part per 50 billion, the odor can be smelled. Thiols and thiophenols are weak acids, their acidity is stronger than the corresponding hydroxyl compounds and weaker than acetic acid. They react with mercury chloride to form insoluble mercury salts, and are also easily oxidized to disulfides by various oxidants. Mercaptans can be produced by the substitution reaction of alkyl halides and sodium hydrosulfide, or by reacting alkyl halides with thiourea and then treating the product with alkali. The high-temperature catalytic reaction between alcohol and hydrogen sulfide can produce cheap ethyl mercaptan and butyl mercaptan in large quantities. Thiols are generally produced by reduction of aromatic sulfonyl chlorides. Some mercaptans and thiophenols can be used as drugs, detoxifiers and rubber vulcanization accelerators, and can also be used as raw materials for synthetic fungicides. For example, thiosalicylic acid can be used to synthesize the fungicide salicyl mercury ； 2-Mercaptobenzothiazole can be used as a vulcanization accelerator for rubber ； 2,3-Dimercaptopropanol can be used as an antidote for arsenic poisoning ； 6-Mercaptopurine can treat cancer.