Patents by Inventor Pang Yih Liu

Pang Yih Liu 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 preparing 2,6-dimethylphenol
    Patent number: 6399838
    Abstract: A process for preparing 2,6-dimethylphenol from 2,4,6-trimethylphenol is provided. The process includes two steps: (1) selective oxidation of 2,4,6-trimethylphenol to 3,5-dimethyl-4-hydroxybenzaldehyde and (2) deformylation of the resulting benzaldehyde to 2,6-dimethylphenol. In step (1), the 2,4,6-trimethylphenol is reacted with oxygen-containing gases at temperatures of 20 to 200° C. in the presence of an iron-containing catalyst, which has higher 3,5-dimethyl-4-hydroxybenzaldehyde selectivity than the known copper-based catalysts. In step (2), a copper-containing catalyst is used to replace the customarily used precious metal catalysts for the effective deformylation of the 3,5-dimethyl-4-hydroxybenzaldehyde to 2,6-dimethylphenol.
    Type: Grant
    Filed: February 2, 2001
    Date of Patent: June 4, 2002
    Assignee: National Science Council
    Inventors: Kuo-Tseng Li, Pang Yih Liu