Pure acetylene is slightly toxic, which has the functions of weak anesthesia and preventing cell oxidation. At high concentration, oxygen in the air is squeezed out, causing simple suffocation. Acetylene is often mixed with phosphine, hydrogen sulfide and other gases, so it is often accompanied by toxic effects of such poisons.
People exposed to 100 mg/m3 can tolerate it for 30 ~ 60 min, of which 20% cause obvious hypoxia, 30% have ataxia, and 35% are unconscious for 5min. When exposed to air containing 10% acetylene for 5 hours, there was mild poisoning reaction.
2. Physical properties:
Pure acetylene is a combustible gas, colorless and fragrant. Acetylene made of calcium carbide is mixed with hydrogen sulfide H? S, phosphine ph? Hydrogen arsenide is toxic and has a special smell. Melting point -80.8℃, boiling point -84℃, relative density 0.6208, refractive index 1.0005 1, refractive index 1.0005, flash point-17.78℃ and spontaneous combustion point 305℃.
The explosion limit in air is 2.3%-72.3%. In liquid and solid state or under gas and certain pressure, there is a danger of violent explosion, which can be caused by heat, vibration, electric spark and other factors, so it cannot be stored or transported after pressurized liquefaction. Slightly soluble in water, soluble in ethanol, benzene and acetone. At 65438 05℃ and 65438±0.5 MPa, the solubility of acetylene in acetone is 237g/L, and the solution is stable.
3, chemical properties:
The simplest alkyne, also known as calcium carbide gas. Structural formula H-C≡C-H, simple structural formula CH≡CH, simplest formula CH, molecular formula C? h？ C atom of acetylene center is hybridized by sp.
The molecular weight of acetylene is 26.4, the specific gravity of gas is 0.9 1(Kg/m3), the flame temperature is 3 150℃, and the calorific value is 12800 (kcal /m3). Pure acetylene burns about 2 100 degrees in air and about 3600 degrees in oxygen.
Extended data:
Matters needing attention in using acetylene
1. Users shall abide by the management system and safety operation rules for the use of gas cylinders and gases, and give safety technical education to operators.
2. Knocking and collision are prohibited during use. When the bottle valve is frozen, it is forbidden to bake it with fire, and it shall not be close to the heat source, and the distance from the open flame shall not be less than 10m.
3. When acetylene bottle and oxygen bottle are used at the same time, the distance between the two bottles should be not less than 5m. Attention should be paid to fixing and preventing dumping. Do not use it lying down. The gas in the bottle must not be used cleanly, and there must be residual pressure gas above 0.05MPa.
4. Special pressure reducer and flashback prevention device must be used. When opening, the operator should stand behind the valve side and move slowly, not too fast or too hard.
5. It is forbidden to place it in a place with poor ventilation, directly on the ground, not on rubber and other insulators to prevent electrostatic fire.
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