Structural Changes of Bagasse dusring the Homogeneous Esterification with Maleic Anhydride in Ionic Liquid 1-Allyl-3-methylimidazolium Chloride

Abstract

Abstract:The maleation of bagasse could greatly increase the compatibility between bagasse and composite matrixes, and the percentage of substitution (PS) of bagasse maleates could be regulated in the homogeneous system. However, due to the complicated components and the linkages of bagasse, it was difficult to control the reaction behaviors of each component. In this paper, the detailed structural changes of bagasse during the homogeneous maleation in ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) were comparatively investigated with the three main components (cellulose, hemicelluloses, and lignin) from bagasse. The PS of the maleated bagasse was 12.52%, and the PS of the maleated cellulose, hemicelluloses, and lignin were 13.50%, 10.89%, and 14.03%, respectively. Fourier translation infrared (FT-IR) and NMR analyses confirmed that the three main components were all involved in the homogeneous maleation. 1 H-13 C HSQC analysis indicated that the predominant monoesterification of cellulose, diesterification of hemicelluloses and lignin, and the degradation of the three main components simultaneously occurred. Besides, the quantitative analysis from 1 H-13 C HSQC revealed the relative PS of reactive sites in each component. 31 P NMR results showed that the reactivity of lignin aliphatic hydroxyls was higher than that of phenolic ones, and the reactivity of phenolic hydroxyls followed the order of p-hydroxyphenyl hydroxyls > guaiacyl hydroxyls > syringyl hydroxyls.

Effect of Lignin Modification on Properties of Kenaf Core Fiber Reinforced Poly(Butylene Succinate) Biocomposites

“…It corresponds to the addition of a double bond C=C of maleic anhydride [24]. An intensified peak near 1159 cm −1 corresponding to C-O symmetric stretching also confirms the occurrence of maleation [25].…”

Determination of hydroxyl groups in biorefinery resources via quantitative 31P NMR spectroscopy

“…A large variety of depolymerization or condensation reactions typically occur within the lignin structure under such conditions. Quantitative 31 P NMR analyses of lignins isolated from various biomass pretreatment technologies have been highlighted in recent studies 101,[108][109][110][111][112][113][114][115][116][117] . As lignin has become a key genetic engineering target for the enhancement of wood quality and biofuel production 118,119 , quantitative 31 P NMR analyses also have been carried out on transgenic lignin 97,120 .…”

Efficient Extraction and Structural Characterization of Hemicellulose from Sugarcane Bagasse Pith

“…The following analyses were based on previous reports [20,28,32,33]. It can be seen that the typical peaks of hemicelluloses were 3420, 1630, 1407, 1043, and 898 cm −1 [34,35]. The peaks of 3420 and 2924 cm −1 were ascribed to the O-H and C-H stretching of hemicellulose, respectively, while the absorption peak at 1407 cm −1 was C-H stretching, and the absorption peak at 1043 cm −1 corresponded to the C-O, C-C stretching or C-OH bending of typical xylose pyran ring.…”