Patents by Inventor Lydia L. Chang

Lydia L. Chang 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).

  • S,S-di-(tertiary alkyl) thiophosphonate insecticides
    Patent number: 4752604
    Abstract: Compounds having the formula ##STR1## in which R is methyl or ethyl, Y is sulfur or oxygen, and R.sub.1 and R.sub.2 are the same or different tertiary alkyl groups each having from 4 to 6 carbon atoms, are insecticides and nematicides, especially for control of soil insects and nematodes.Symmetrical compounds (R.sub.1 .dbd.R.sub.2) may be prepared by reaction of an alkali metal mercaptide with an alkyl (thio) phosphonic dihalide. The alkali metal mercaptide may be prepared by reaction of a tertiary alkyl mercaptan with an alkali metal or alkali metal hydride.
    Type: Grant
    Filed: July 3, 1986
    Date of Patent: June 21, 1988
    Assignee: Stauffer Chemical Company
    Inventors: Charles G. Chavdarian, Lydia L. Chang, Bruce C. Onisko, Jonathan P. Earhart