| Chemical Industry-Propylene oxide |
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Propylene oxide
Propylene oxide or 1,2-epoxy-propane (PO), is a very reactive substance and one of the most important chemical intermediates. After the production of PVC, the chlorination of propylene is the second largest single chlorine outlet.
PO can be industrially manufactured via direct or indirect oxydation (Oxirane-process) or via the classical chlorohydrin process in which chlorine plays a role. About 45 % of the world PO-production capacity is based on this route.
The chlorohydrin process consists of two steps.
In the first step propene and chlorine react in an aqueous solution. A mixture of 90 % 1-chloro-2-propanol (90%) and 10 % 2-chloro-1-propanol is obtained.
CH3-CH=CH2 + HOCl -> CH3-COH-CH2Cl + CH3-CHCl-CH2OH
During the second step, the mixture is dehydrochlorinated with a base, either lime Ca(OH)2 or caustic soda; the obtained PO is removed with steam and subsequently purified via distillation.
CH3-COH-CH2Cl + Ca(OH)2 -> CH3CH(O)CH2 + CaCl2 + 2 H2O
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