Patents by Inventor Fred Hendrik van der Steen

Fred Hendrik van der Steen 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 for synthesis of a dilithium diisopropenylbenzene-based diinitiator
    Patent number: 6217798
    Abstract: This invention is a process for making a difunctional lithium initiator which comprises reacting a secondary or tertiary lithium alkyl with a diisopropenylbenzene compound in the presence of diethyl ether at a temperature of 25 to 50° C. wherein the molar ratio of the diethyl ether to the lithium alkyl is from above 0.1:1 to 2:1 and the diisopropenylbenzene compound and the diethyl ether are first mixed together and then added to the lithium alkyl. The molar ratio of the diisopropenylbenzene compound to the lithium alkyl should be as close to 0.5:1 as possible. An excess of lithium alkyl may be used if a product containing both diinitiator and monoinitiator is preferred. It is preferred that the molar ratio of diethyl ether to lithium alkyl be as close to 1:1 as possible.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: April 17, 2001
    Assignee: Shell Oil Company
    Inventors: Carl Lesley Willis, Grant Wesley Haddix, David Karl Schisla, Fred Hendrik van der Steen