Patents by Inventor Dieter Freudenberger

Dieter Freudenberger 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).

  • Process for the extraction of carboxylic acids from dilute aqueous solutions
    Patent number: 4720577
    Abstract: The invention relates to a process for the extraction of carboxylic acids from aqueous solutions with a carboxylic acid content below 8% by weight. A mixture of an aliphatic amine with a total carbon number of at least 10 and a phenol or naphthol is used as extracting agent. The molar ratio of phenol:amine or alkylated phenol:amine or naphthol:amine is in the range from 0.1:1 to around 1.1:1.
    Type: Grant
    Filed: October 2, 1985
    Date of Patent: January 19, 1988
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Bernhard Wojtech, Walter Steppich, Dieter Freudenberger, Knut Riedel
  • Process for separating p-benzoquinone from the reaction products of phenol oxidation as quinhydrone
    Patent number: 4235790
    Abstract: A process for separating p-benzoquinone as quinhydrone from the reaction solution obtained in the oxidation of phenol with oxygen in the presence of copper salts and of nitriles as the solvent, which comprises suspending and/or dissolving solid hydroquinone in this reaction solution, precipitating the p-benzoquinone contained therein as quinhydrone and separating it from the reaction solution.
    Type: Grant
    Filed: January 22, 1979
    Date of Patent: November 25, 1980
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Werner H. Muller, Dieter Freudenberger
  • Process for the preparation of ethylene glycol
    Patent number: 4214106
    Abstract: Process for the preparation of ethylene glycol by hydrogenating glycolic acid in the presence of catalysts containing elements or compounds of elements from at least two of the groups VIII, VIIb and Ib of the Periodic System.
    Type: Grant
    Filed: April 5, 1978
    Date of Patent: July 22, 1980
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Dieter Freudenberger, Friedrich Wunder
  • Process for the manufacture of vinyl acetic acid
    Patent number: 4140865
    Abstract: Vinylacetic acid and optionally .gamma.-butyrolactone are prepared by reacting an allyl compound substituted by oxygen functions with carbon monoxide in the presence of a heavy metal catalyst. When the reaction is carried out with an allyl ether or a carboxylic acid allyl ester, water is added. Vinylacetic acid is obtained in a very good yield in simple and economic manner.
    Type: Grant
    Filed: March 12, 1976
    Date of Patent: February 20, 1979
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Hans Fernholz, Dieter Freudenberger
  • Process for the catalytic manufacture of .gamma.-butyrolactone
    Patent number: 4096156
    Abstract: .gamma.-BUTYROLACTONE, WHICH IS AN IMPORTANT PRELIMINARY PRODUCT FOR THE PREPARATION OF BUTANEDIOL-(1,4) AND OF PYRROLIDONE, IS MANUFACTURED BY CATALYTIC HYDROGENATION OF MALEIC ACID, MALEIC ACID ANHYDRIDE, SUCCINIC ACID, SUCCINIC ACID ANHYDRIDE, OR FUMARIC ACID, OR OF A MIXTURE OF TWO OR MORE OF THESE COMPOUNDS, USING A CATALYST CONTAINING A MIXTURE OF AN ELEMENT OF THE VIII.sup.th subgroup of the periodic system of elements or of one of its compounds with an element of the I.sup.st subgroup of the periodic system of elements or of one of its compounds. The process is highly selective, and the yields of .gamma.-butyrolactone are, therefore, excellent.
    Type: Grant
    Filed: November 23, 1976
    Date of Patent: June 20, 1978
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Dieter Freudenberger, Friedrich Wunder, Hans Fernholz
  • Process for the manufacture of vinyl acetic acid and optionally of .gamma.- b
    Patent number: 3980671
    Abstract: Vinylacetic acid and optionally .gamma.-butyrolactone are prepared by reacting an allyl compound substituted by oxygen functions with carbon monoxide in the presence of a heavy metal catalyst. When the reaction is carried out with an allyl ether or a carboxylic acid allyl ester water is added. Vinylacetic acid is obtained in a very good yield in simple and economic manner.
    Type: Grant
    Filed: April 9, 1973
    Date of Patent: September 14, 1976
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Hans Fernholz, Dieter Freudenberger
  • Process for the continuous preparation of hydroxypivaldehyde
    Patent number: 3935274
    Abstract: Process for the continuous preparation of hydroxypivalaldehyde by the reaction of isobutyraldehyde with aqueous formaldehyde in a cascade of stirred vessels in the presence of an alcohol and of an alkali metal hydroxide as a catalyst.
    Type: Grant
    Filed: April 21, 1969
    Date of Patent: January 27, 1976
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Gunter Jacobsen, Hans Fernholz, Dieter Freudenberger