The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 1992
Filed:
Apr. 08, 1991
Applicant:
Inventors:
Siegbert Rittner, Morfelden-Walldorf, DE;
Adolf Schmidt, Hofheim am Taunus, DE;
Rudolf Steiner, Erlangen-Kosbach, DE;
Leonhard Unverdorben, Uttenreuth, DE;
Assignee:
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B01D / ; C07C / ;
U.S. Cl.
CPC ...
203 48 ; 203 60 ; 203 91 ; 570211 ;
Abstract
A process for separating m- and p-dichlorobenzene by extractive rectification with an extractant and removal of this extractant. Using as extractant an alkylene carbonate of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical to or different from one another and each is hydrogen, methyl or ethyl, with the proviso that together the radicals R.sup.1 to R.sup.4 do not contain more than 6 carbon atoms. The process of the invention makes it possible to separate off the m-isomer in high purity.