PRODUCTION OF ETHYLENE GLYCOL
Ethylene glycol used to be manufactured by the hydrolysis of ethylene oxide (EO) which was made via ethylene chlorohydrin but this method has been superseded by a direct oxidation route. EO is first produced by the oxidation of ethylene in the presence of oxygen or air and a silver oxide catalyst. A crudeethylene glycol mixture is produced by the hydrolysis of the EO with water under pressure. The water-glycol mixture is moved towards evaporators where the water is recovered and then recycled to be used in the process again. Fractional distillation under a vacuum is used to separate the monoethylene glycol from the diethylene and triethylene glycols.
C2H4O + H2O → HO–CH2CH2–OH
This reaction can be catalyzed by either acids or bases, or can occur at neutral pH under increased temperatures. The highest yields of ethylene glycol occur at acidic or neutral pH with a large excess of water. Under these conditions, ethylene glycol yields of 90% can be achieved. The major byproducts are the ethylene glycol oligomers diethylene glycol, triethylene glycol, and tetraethylene glycol. Over 73 millions tons are produced annually. Ethylene glycol is a chemical commonly used in many commercial and industrial applications including antifreeze and coolant. Other important uses of ethylene glycol include heating, ventilating, and air-conditioning systems, and it is even used in ice skating rinks.
C2H4O + H2O → HO–CH2CH2–OH
This reaction can be catalyzed by either acids or bases, or can occur at neutral pH under increased temperatures. The highest yields of ethylene glycol occur at acidic or neutral pH with a large excess of water. Under these conditions, ethylene glycol yields of 90% can be achieved. The major byproducts are the ethylene glycol oligomers diethylene glycol, triethylene glycol, and tetraethylene glycol. Over 73 millions tons are produced annually. Ethylene glycol is a chemical commonly used in many commercial and industrial applications including antifreeze and coolant. Other important uses of ethylene glycol include heating, ventilating, and air-conditioning systems, and it is even used in ice skating rinks.