Patents by Inventor Takeshi Sekoguchi

Takeshi Sekoguchi 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 purifying .alpha.-amino-.epsilon.-caprolactam
    Patent number: 4140686
    Abstract: Purified .alpha.-amino-.epsilon.-caprolactam free from not only visible ray-absorbing substances but ultra-violet ray-absorbing substances, such as, tetrahydrophenazine and octahydrophenazine, and volatile basic substances such as, ammonium salts, is obtained by dissolving a crude .alpha.-amino-.epsilon.-caprolactam in a solvent consisting of at least one alkyl ester of saturated aliphatic acid of the formula:C.sub.m H.sub.2m+1 COOC.sub.n H.sub.2n+1wherein m is 1 or 2 and n is 1, 2, 3 or 4, at an elevated temperature at which the crude material can be completely dissolved in the solvent, cooling the solution to a lowered temperature at which the .alpha.-amino-.epsilon.caprolactam is allowed to recrystallize from the solution, and separating the crystals of the purified .alpha.-amino-undecanoic acid from the solution.
    Type: Grant
    Filed: October 25, 1977
    Date of Patent: February 20, 1979
    Assignee: Toray Industries, Inc.
    Inventors: Ichiro Kawamoto, Takeshi Sekoguchi, Yoshihiro Shibai