Patents by Inventor Volker Häfner

Volker Häfner 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).

  • Publication number: 20090192309
    Abstract: The invention relates to an improved process for preparing triallyl cyanurate (TAC) by reacting cyanuric chloride with allyl alcohol in the presence of an alkali metal acid acceptor and in the absence of an organic solvent other than allyl alcohol. According to the invention, TAC is obtained in over 99% purity with an APHA colour number below 10 in a yield of over 90% when 3.9 to 6.0 mol of allyl alcohol and 3.0 to 3.2 equivalents of acid acceptor are used per mole of cyanuric chloride, cyanuric chloride and acid acceptor are added simultaneously or successively to anhydrous or at least 50% by weight aqueous allyl alcohol, and the reaction is performed in one or more stages at a temperature in the range of ?5 to +50° C.
    Type: Application
    Filed: June 25, 2007
    Publication date: July 30, 2009
    Applicant: Evonik Degussa GmbH
    Inventors: Volker Häfner, Helmut Suchsland, Peter Werle
  • Patent number: 7148379
    Abstract: A process for the preparation of 2-hydroxy-4-methylthiobutyric acid.
    Type: Grant
    Filed: August 25, 2005
    Date of Patent: December 12, 2006
    Assignee: Degussa AG
    Inventors: Alexander Möller, Hans-Albrecht Hasseberg, Harald Heinzel, Volker Häfner
  • Patent number: 6566559
    Abstract: Process for the production of unsaturated ethers, in particular isopropenyl methyl ether (IPM), by pyrolysis of a ketal-containing or acetal-containing mixture, in particular dimethoxypropane (DMP), in the liquid phase in the presence of an organic carboxylic acid, according to the following reaction scheme: wherein R1=H or alkyl with 1-8 C atoms; R2=H, CH3—, C2H5—, or Cl—; R3=alkyl with 1-8 C atoms; R4=H, CH3—, C2H5—, or C3H7—, and R1 and R4 may be joined to form a 5-, 6-, or 7-membered ring. DMP is produced by the process from acetone and methanol by reaction in an acidic heterogeneous ion exchanger, the product being isolated by extraction with aqueous alkaline solution. In particular the process involves combining the IPM reaction product with the DMP reaction product, which permits the execution of a stable recycling process in which the methanol-containing streams of the IPM and DMP stages can be simultaneously extracted.
    Type: Grant
    Filed: June 1, 2001
    Date of Patent: May 20, 2003
    Assignee: Degussa AG
    Inventors: Steffen Krill, Stephan Kretz, Volker Häfner, Georg Markowz