REACTIVITY TOWARD PHENOL OF LIGNIN FROM THE HYDROLYSIS OF SWEETGUM WOOD WITH CONCENTRATED SULFURIC-ACID

Sweetgum wood was hydrolyzed at 20° and 50° C for different time periods with 68% sulfuric acid. The lignin residues obtained were subjected to a phenolation reaction. For lignin prepared at the lower temperature the maximum phenol uptake was 9.5%, and at the higher temperature only 5-6%. When wood prehydrolyzed with dilute acid was used the phenol uptake rose to 12.5%. However, all the sulfuric acid hydrolysis lignins showed much lower reactivity toward phenol than the 20% phenol uptake exhibited by lignin isolated using concentrated hydrochloric acid. © 1990, Taylor & Francis Group, LLC. All rights reserved.