Process for the preparation of 1,2-dichloroethane

Die Erfindung betrifft ein Verfahren zur Herstellung von 1,2-Dichlorethan durch Umsetzung von Ethylen und Chlor in einer Reaktionszone, welche ein umlaufendes flüssiges Medium mit einem Gehalt an chlorierten Kohlenwasserstoffen mit zwei Kohlenstoffatomen sowie einen zur Chlorübertragung üblichen Katalysator enthält, bei einer Temperatur von etwa 75-200 °C, einem Druck von etwa 1-15 bar und einer mittleren Verweilzeit des Gemisches in der Misch- und Reaktionszone von etwa 1-15 Stunden, welches dadurch gekennzeichnet ist, daß man die Herstellung des 1,2-Dichlorethans in einem Doppelschlaufenreaktor durchführt. 1. An improved process for making 1,2-dichloroethane by reacting ethylene and chlorine in a reaction zone having a liquid medium containing chlorinated C2 -hydrocarbons circulated therein in the presence of a customary chlorination-including catalyst and optionally an inhibitor reducing the formation of by-products, wherein a) approximately equimolar proportions of ethylene and chlorine are introduced into the circulated liquid medium, the whole is mixed, and the mixture is reacted in a reaction zone at a temperature of about 75-200 degrees C under a pressure of about 1-15 bars, and during a mean sojourn time of the mixture in the mixing and reaction zone of about 1-15 hours ; wherein b) a portion of the liquid reaction mixture is removed from the reaction zone and subdivided into two partial streams, of which one is passed through a heat exchanger for dissipation of calorific energy and recycled at reduced temperature to the mixing and reaction zone, whilst the second partial stream is introduced into an expansion vessel in which a proportion adequate to the reaction product formed in the reaction zone is evaporated from the said second partial stream, the resulting vapors are introduced into a fractionating column and 1,2-dichloroethane is distillatively separated, whereas the unevaporated liquid fraction of the second partial stream is recycled into the liquid medium circulated in the mixing and reaction zone, which comprises preparing the 1,2-dichloroethane inside a double loop reactor by A) introducing ethylene through line (1) and chlorine gas through line (2) into the ascending portion of loop (I) below the mixing zone (3) in the asending portion and finely distributing them in the liquid medium circulated through loop (I), and then reacting the reaction components in reaction zone (4) and sojourn zone (5), respectively, following mixing zone (3