We tried to produce cellulose acetate butyrate using the conventional method by Eastman (using sulfuric acid as the catalyst). The cellulose was derived from peanut shells.
Pre-treatment with Acetic Acid: 4 hours
Esterification with Butyric Acid, Acetic Anhydride, and Butyric Anhydride: 8 hours
Hydrolysis with 70% Acetic Acid solution: 4 hours
The resulting mixture was precipitated in a large volume of cold water. The precipitate was black in color. How can I remedy this so I can expect a white cellulose acetate butyrate?
Thanks in advance.
Tristan,
Replacing traditional cellulose types by alternative, less pure grades most often results in severe coloration issues. If the same method gives a lightly colored product with another reference cellulose type, such as a chemical cotton or wood pulp cellulose, then you can be sure that impurities in the peanut shell cellulose cause the coloration problem.
Peter Arisz
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