The preparation of ethylene chlorohydrin as an intermediate in the manufacture of ethylene oxide and ethylene glycol is carried out in the following manner. C2H4 + Cl2 + H2O → CH2OHCH2Cl + HCl (1) ; CH2OHCH2Cl + ½ Ca(OH)2 → C2H4O + ½ CaCl2 + H2O (2) ; C2H4 + Cl2 → ClCH2CH2Cl (3). Ethylene, chlorine and water as indicated in reaction (1), are reacted together continuously at about 2.5 atm pressure, in the reaction tower of a plant. This is made of steel, lined with rubber and acid resistant tile, and is packed with Raschig rings. Water enters at the lowest point, the chlorine is admitted through a distributor approximately 2 m higher, and ethylene is fed in by a blower at a point 2 m above the chlorine inlet through a distributor star.

By : Stephanus Sulaeman@upv.pertamina

ETHYLENE CHLOROHYDRIN

The preparation of ethylene chlorohydrin as an intermediate in the manufacture of ethylene oxide and ethylene glycol is carried out in the following manner.

C2H4 + Cl2 + H2O → CH2OHCH2Cl + HCl (1)

CH2OHCH2Cl + ½ Ca(OH)2 → C2H4O + ½ CaCl2 + H2O (2)

C2H4 + Cl2 → ClCH2CH2Cl (3)

Ethylene, chlorine and water as indicated in reaction (1), are reacted together continuously at about 2.5 atm pressure, in the reaction tower of a plant. This is made of steel, lined with rubber and acid resistant tile, and is packed with Raschig rings. Water enters at the lowest point, the chlorine is admitted through a distributor approximately 2 m higher, and ethylene is fed in by a blower at a point 2 m above the chlorine inlet through a distributor star.

The delivery of the three components to the reaction tower is measured by orifice meters as well as by recording meters. The reaction is exothermic, and the temperature in the reactor rises to 40-60oC, the optimum is about 50oC. The mixture of the reaction components is so regulated that a 4.5% – 5% ethylene chlorohydrin solution is obtained. In this way the chlorine is completely absorbed without circulation, while the ethylene is used in excess. The off-gases containing ethylene leave the reactor at the highest point and pass to another similar tower that has a water seal of about 2m so that a corresponding pressure is maintained in the primary chlorinator.

Selengkapnya :