Selective aerobic alcohol oxidation method for conversion of lignin into simple aromatic compounds
AssigneeWisconsin Alumni Research Foundation
InventorsShannon S. Stahl, Alireza Rahimi
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Abstract
Described is a method to oxidize lignin or lignin sub-units. The method includes oxidation of secondary benzylic alcohol in the lignin or lignin sub-unit to a corresponding ketone in the presence of unprotected primarily aliphatic alcohol in the lignin or lignin sub-unit. The optimal catalyst system consists of HNO3 in combination with another Brønsted acid, in the absence of a metal-containing catalyst, thereby yielding a selectively oxidized lignin or lignin sub-unit. The method may be carried out in the presence or absence of additional reagents including TEMPO and TEMPO derivatives.
Claims21
A method to oxidize lignin or lignin sub-units, the method comprising selectively oxidizing at least a portion of secondary benzylic alcohol groups in the lignin or lignin sub-unit to corresponding ketones while leaving unchanged at least a portion of unprotected primary aliphatic alcohols in the lignin or lignin sub-unit by contacting the lignin or lignin sub-unit with a catalyst comprising nitric acid (HNO3) in combination with another Brønsted acid, in the absence of a metal-containing catalyst, thereby yielding a selectively oxidized lignin or lignin sub-unit.
Dependencies are inferred from the claim text.