Patents by Inventor Paul Riegger

Paul Riegger has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method of preparing xylenes chlorinated in the nucleus
    Patent number: 4166075
    Abstract: An improvement in a process for preparing a xylene chlorinated in the nucleus by contacting the xylene with chlorine in the presence of a catalyst, the improvement residing in employing as the catalyst an iron halide or antimony halide and employing a co-catalyst which is an aliphatic, halogenated or nonhalogenated hydrocarbon having an oxygen function.
    Type: Grant
    Filed: January 18, 1978
    Date of Patent: August 28, 1979
    Assignee: Dynamit Nobel Aktiengesellschaft
    Inventors: Georg Blumenfeld, Paul Riegger
  • Method of preparing terephthalic acid dichloride and isophthalic acid dichloride
    Patent number: 4091017
    Abstract: Production of terephthalic acid dichloride and isophthalic acid dichloride by hydrolysis with water as a gas according to the following overall reaction: ##STR1## A Friedel-Crafts catalyst is used and some of the dichloride produced is maintained present throughout the reaction. The reaction is fast and the yield is high.
    Type: Grant
    Filed: July 12, 1976
    Date of Patent: May 23, 1978
    Assignee: Dynamit Nobel Aktiengesellschaft
    Inventors: Hermann Richtzenhain, Paul Riegger
  • Process for the preparation of .alpha.,.alpha.,.alpha..alpha.',.alpha.'-pentachloro-o-xylene
    Patent number: 4056454
    Abstract: Process for the preparation of .alpha., .alpha.,.alpha.,.alpha.',.alpha.'-pentachloro-o-xylene by the reaction of o-xylene with chlorine in the presence of solvent and under actinic light radiation, characterized in that the reaction is performed at temperatures above 75.degree. up to 140.degree. C with carbon tetrachloride as solvent, with the introduction of chlorine, or in some cases by means of chlorine activated in the gas phase.
    Type: Grant
    Filed: August 2, 1976
    Date of Patent: November 1, 1977
    Assignee: Dynamit Nobel Aktiengesellschaft
    Inventors: Paul Riegger, Hermann Richtzenhain, Gunter Zoche