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:
Apr. 19, 1988
Filed:
May. 30, 1986
Manji Sasaki, Ibaraki, JP;
Chinehito Ebina, Minoo, JP;
Haruki Okamura, Osaka, JP;
Shinichi Yachigo, Toyonaka, JP;
Tamaki Ishii, Suita, JP;
Sumitomo Chemical Company, Limited, Osaka, JP;
Abstract
Method for the purification of 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dime thylethyl} -2,4,8,10-tetraoxaspiro[5.5]undecane, to form crystals having a crystalline structure which, when subjected to Cu-K.sub..alpha. X-ray diffraction, show sharp X-ray diffraction peaks at angles of diffraction, to 2.theta.=2.8.degree., 2.theta.=8.7.degree. and 2.theta.=11.7.degree., by recrystallizing the ester at a temperature lower than 40.degree. C. using as a recrystallization solvent, A C.sub.5 -C.sub.10 alicyclic hydrocarbon, which may contain a limited amount of certain other solvents, or using a mixed solvent of a C.sub.5 -C.sub.10 aliphatic hydrocarbon and at least one other certain solvent in a certain weight ratio.