The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1994
Filed:
Jan. 14, 1993
Applicant:
Inventors:
Shinya Tanaka, Toyonaka, JP;
Manji Sasaki, Nishinomiya, JP;
Shinichi Yachigo, Toyonaka, JP;
Hiroki Yamamoto, Niihama, JP;
Eiiti Yoneyama, Niihama, JP;
Assignee:
Sumitomo Chemical Company, Limited, Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
546186 ;
Abstract
Crude N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)alkanediamine represented by the formula: ##STR1## wherein n is an integer of 2 to 10, is purified by crystallization from a ketone solvent of 3 to 9 carbon atoms. The purified product thus obtained has a purity of 98% by weight or more, a 2,2,6,6-tetramethyl-4-piperidone content of 150 ppm or less, and an initial APHA value of 30 or less. The purified product is also inhibited from discoloration with the passage of time.