2. Ethylene oxide hydration method, which includes direct hydration method and catalytic hydration method. The hydration process can be carried out under normal pressure or pressure.
3. At present, there is a gas-phase catalytic hydration method, which uses silver oxide as catalyst and alumina as carrier to generate ethylene glycol at 150 ~ 240℃.
4. Direct hydration of ethylene In the presence of catalyst, ethylene is oxidized in acetic acid solution to produce monoacetate or diacetate, and then further hydrolyzed to obtain ethylene glycol.
5. Ethylene oxide and water have hydration reaction under the action of sulfuric acid catalyst, and the reaction solution is neutralized by alkali, evaporated and rectified to obtain the finished product.
6. Formaldehyde method.
7. Using industrial ethylene glycol as raw material, the middle distillate can be collected after 1333Pa vacuum distillation.
8. Vacuum distillation of ethylene glycol, drying the main fraction with anhydrous sodium sulfate for a long time, and then vacuum distillation again with a good fractionator.
Extended data:
Toxic environment of ethylene glycol:
Toxicity: low toxicity.
Acute toxicity: LD 508.0 ~ 15.3 g/kg (mice); 5.9 ~ 13.4 g/kg (taken orally by rats); 1.4ml/kg (oral, fatal)
Subacute and chronic toxicity: 8 days after rats inhaled 12mg/m3 (repeated), 2/ 15 animals appeared corneal opacity and blindness; People inhaled 40% ethylene glycol mixture, and 9/28 people fainted briefly; People inhale 40% ethylene glycol mixture and heat it to 105℃. Repeated inhalation 14/38 people have nystagmus, and 5/38 people have increased lymphocytes.
Hazard characteristics: In case of open flame, high heat or contact with oxidant, there is danger of combustion and explosion. In case of high heat, the internal pressure of the container rises, which is in danger of rupture and explosion.
Combustion (decomposition) products: carbon monoxide, carbon dioxide, water.
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