Patents by Inventor Dacheng Gao

Dacheng Gao 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 purifying long-chain dicarboxylic acid
    Patent number: 6218574
    Abstract: The present invention relates to an aqueous phase process for purifying long-chain dicarboxylic acids from a liquid containing a long-chain dicarboxylic acid/or a salt thereof. The invention overcomes the disadvantages of low purity and high chroma of the product obtained by using the aqueous phase process of the prior art. Through the step of crystallizing the monosalt of long-chain dicarboxylic acid, the present process reduces effectively the content of such impurities as proteins and coloring materials in the product and obtains the long-chain dicarboxylic acid product having a total acid content of greater than 99 wt % and exhibiting a white appearance.
    Type: Grant
    Filed: December 2, 1999
    Date of Patent: April 17, 2001
    Assignees: China Petrochemical Corporation, Fushun Research Institute of Petroleum & Petrochemical
    Inventors: Shuchen Liu, Dacheng Gao, Jiangang Zhang