Patent ID: 7311807
Filing Date: 2007-12-25
Classification: C07C,Y10S

Abstract:
1. A process for the separation of dichlorobenzene mixtures containing m- and p-dichlorobenzene by extractive rectification wherein: (I) the mixture is contacted either with one phosphoric ester of the general formula (I) as an extracting agent wherein R 1 , R 2 and R 3 are identical or different and are selected from the group consisting of aliphatic or cycloaliphatic alkyl or alkenyl radical wherein R 1 , R 2 and R 3 together contain at least 3C-atoms and not more than 12 C-atoms, or a mixture of phosphoric esters of formula (I) or is contacted with one phosphine oxide of the general formula (II) as an extracting agent in which R 1 , R 2 and R 3 are identical or different and are selected from the group consisting of aliphatic or cycloaliphatic alkyl or alkenyl radical or hydrogen, wherein R 1 , R 2 and R 3 together contain at least 3 C-atoms and not more than 12 C-atoms, or a mixture of phosphine oxides of formula (II) or a mixture of phosphoric esters of formula (I) and phosphine oxides of formula (II), and subsequently (ii) the components of the mixture are separated into a m-dichlorobenzene- and a p-dichlorobenzene-containing fraction, and finally (iii) the extracting agent is separated from one of the fractions obtained.