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:
Mar. 29, 1994
Filed:
Apr. 02, 1993
Applicant:
Inventors:
Wen-Fa Lin, Hsinchu, TW;
Jun-Yi Chen, Hsinchu, TW;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07C / ; C07C / ;
U.S. Cl.
CPC ...
568617 ; 568621 ;
Abstract
Polytetramethylene ether glycols (PTMEG) are fractionated with liquid propane in an extractor under high pressure. Fractions are separated by altering the extraction pressure, which alters the solvent power of the propane. The polydispersities of all extracted PTMEG fractions are generally below 1.3. The addition of a cosolvent, preferably tetrahydrofuran, can effectively lower the initial extraction pressure and increase the efficiency of the extraction.