POTENTIOMETRIC STUDIES OF OXIDES OF CHROMIUM

jute fibre has been acetylated with acetic anhydride in the presence of acetic acid and potass­ium acetate, and acetylated cellulose as well as acetylated lignin isolated from the treated fibre. The degrees of acetylation of these components indicate that whereas the lignin became fully acetylated in a relatively short time. e.g. after boiling for 2 hours, the rate of acetylation -of the cellulose was very mulch slower and was nor complete after 48 hours under the conditions used. After a treatment lasting for 48 hours. the isolated lignin has a higher acetic acid content and a lower methoxyl content than that normally associated with lignin, and it is suggested that this increase in acetic acid content rakes place at the expense of methoxyl groups. There are indications that polyuronide hemicelluloses are removed from the fibre during acetylation