A convenient acetylation of sugarcane bagasse using NBS as a catalyst for the preparation of oil sorption-active materials

Abstract

The esterification of sugarcane bagasse with acetic anhydride using N-bromosuccinimide (NBS) as a catalyst under mild conditions in a solvent free system has been investigated. The extent of acetylation was measured by weight percent gain, which increased with an increment of reaction temperature (30–120°C) and time (0.5–72.0 h) and NBS concentration from 0.5 to 1.5%. In comparison with four tertiary amine catalysts (4-dimethylamino pyridine, pyridine, N-methyl pyrrolidine, and N-methyl pyrrolidinone) and one acidic catalyst (0.5% H₂SO₄), N-Bromosuccinimide was found to be the most effective and inexpensive catalyst for acetylation of hydroxyl groups in the cell walls of bagasse under mild reaction conditions. At a concentration of 1.5% of the NBS catalyst in acetic anhydride, a weight percent gain of 22.3% was achieved at 80°C for 2 h. FT-IR and CP-MAS ¹³C-NMR studies produced evidence for acetylation. More importantly, the acetylation substantially increased hydrophobic properties of the bagasse. The oil sorption capacity of the acetylated bagasse (18.8 g machine oil/g of bagasse fibre at room temperature), obtained at 80°C for 2 h, was approximately 1.9 times higher than those of the commercial synthetic oil sorbents such as polypropylene fibres. Cyclic sorption/desorption studies showed that a simple squeezing operation was sufficient to remove most of the oil absorbed on the fibre and the sorbents can be used several times. These novel oil sorption-active materials could be used to substitute those of non-biodegradable materials in oil spill cleanup.