Xylene (二甲苯) is a colorless and transparent liquid; it is a product in which two hydrogens on the benzene ring are replaced by methyl groups. There are three isomers of ortho, meta and para. In industry, xylene refers to the above isomers. mixture.
Properties
Colorless and transparent liquid. There is a special smell of aromatic hydrocarbons.
It is a mixture of three isomers consisting of 45% to 70% meta-xylene, 15% to 25% para-xylene and 10% to 15% o-xylene. Easy to flow. It is miscible with absolute ethanol, ether and many other organic solvents
Xylene has a pungent odor and is flammable. It can be mixed with ethanol, chloroform or ether at will, and it is insoluble in water. The boiling point is 137～140℃. Xylene is a low-toxic chemical substance, and the American Conference of Governmental Industrial Hygienists (ACGIH) classifies it as A4, that is, a substance that lacks evidence of carcinogenicity to humans and animals. In plastics, fuels, rubber, various coating additives, various adhesives, and waterproof materials, combustion gases can also come from fuel and tobacco.
Security measures
Store in a low-temperature ventilated place, away from fire and heat sources. Avoid co-storage and transportation with oxidants. It is forbidden to use tools that are prone to sparks.
Extinguishing: foam, carbon dioxide, dry powder, sandy soil.
Usage function
It is widely used as a solvent in coatings, resins, dyes, inks and other industries; as a synthetic monomer or solvent in industries such as medicine, explosives, and pesticides; it can also be used as a component of high-octane gasoline and an important raw material for organic chemicals. It can also be used to remove asphalt from the car body. The hospital pathology department is mainly used for the transparency and dewaxing of tissues and sections.
Industrial o-xylene is used as the raw material, first washed with industrial concentrated sulfuric acid until the acid layer is colorless, and then washed with 10% sodium hydroxide solution and water until it is qualified. After separating the water layer, it is dried with anhydrous calcium chloride, and then rectified. After the distillate is clear, collect the middle distillate, which is the pure product.
Leakage emergency response
Quickly evacuate personnel from the contaminated area to a safe area, isolate them, and strictly restrict access. Cut off the fire source. It is recommended that emergency personnel wear self-contained positive pressure breathing apparatus and fire protective clothing. Cut off the source of leakage as much as possible to prevent entry into restricted spaces such as sewers and flood drains. Small leakage: Use activated carbon or other inert materials to absorb. It can also be scrubbed with an emulsion made of a non-flammable dispersant, and the lotion is diluted and put into the waste water system. A large amount of leakage: construct a dike or dig a pit for storage; cover with foam to prevent evaporation. Use explosion-proof pump to transfer to tank truck or special collector, recycle or transport to waste disposal site for disposal. Quickly collect the soil contaminated by xylene and move it to a safe area. Strengthen the ventilation along the ground in the contaminated area, evaporate the residual liquid, and remove the vapor. Quickly build dams, cut off the flow of contaminated water bodies, and use fences to limit the diffusion of xylene on the water surface.
Protection measures
Respiratory protection: When the concentration in the air is high, wear a filter gas mask (half mask). It is recommended to wear an air respirator during emergency rescue or evacuation.
Eye protection: wear chemical safety glasses.
Body protection: wear protective overalls.
Hand protection: wear rubber gloves.
Others: Smoking, eating and drinking are prohibited at the work site. After work, take a shower and change clothes. Pay attention to personal hygiene.
First aid measures
Skin contact: Take off contaminated clothing and wash skin thoroughly with soap and water.
Eye contact: Lift the eyelid and rinse with running water or normal saline. Seek medical attention.
Inhalation: quickly leave the scene to a place with fresh air. Keep the airway unobstructed. If breathing is difficult, give oxygen. If breathing stops, give artificial respiration immediately. Seek medical attention.
Ingestion: Drink enough water to induce vomiting. Seek medical attention.
Fire fighting method
Spray water to cool the container, and move the container from the fire scene to an open place if possible. Extinguishing agent: foam, carbon dioxide, dry powder, sand.
Dangerous characteristics
Flammable, its vapor and air can form an explosive mixture. Exposure to open flames and high heat can cause combustion and explosion. It can react with oxidants. If the flow rate is too fast, it is easy to generate and accumulate static electricity. Its vapor is heavier than air and can spread to a relatively far place at a lower level, and will cause back-combustion in case of an open flame.
Combustion (decomposition) products: carbon monoxide, carbon dioxide.
Packaging, storage and transportation
Packed in galvanized iron drum, 180kg per drum. It can also be shipped by tanker.