Patents by Inventor Richard E. Crooks

Richard E. Crooks 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).

  • Preparation of symmetrical tetrachloropyridine
    Patent number: 4322538
    Abstract: Symmetrical tetrachloropyridine (2,3,5,6-tetrachloropyridine) is prepared by reacting pentachloropyridine with a source of iodide ions in the presence of a proton source and a solvent medium. The reaction is preferably carried out in a polar, aprotic solvent medium and heated at a temperature of from about 100.degree. C. to about 200.degree. C.
    Type: Grant
    Filed: April 20, 1981
    Date of Patent: March 30, 1982
    Assignee: The Dow Chemical Company
    Inventors: Gail E. Vrieland, Bart J. Bremmer, Richard E. Crooks
  • Process for preparing 4-bromotetrachloropyridine
    Patent number: 4321389
    Abstract: A process for producing 4-bromotetrachloropyridine or symmetrical tetrachloropyridine in high purity comprises the selective transhalogenation of pentachloropyridine by a bromide salt in a polar aprotic solvent at a temperature from about 100.degree. C. to about 140.degree. C. followed optionally by selective debromination by hydrogen in the presence of a noble metal catalyst and an acid acceptor to form tetrachloropyridine.
    Type: Grant
    Filed: June 16, 1980
    Date of Patent: March 23, 1982
    Assignee: The Dow Chemical Company
    Inventors: G. Edwin Vrieland, Bart J. Bremmer, Richard E. Crooks