Hansen Solubility Parameters: A Tool for Solvent Selection for Organosolv Delignification

Abstract

The high polysaccharide content of sugar cane bagasse associated with its availability makes it a promising source of fermentable sugars for the production of secondgeneration ethanol. In this context, the separation the macro components in the cell walls of sugar cane bagasse can be performed by organosolv processes. This research was carried out to study the effect of the solvents on the organosolv delignification of sugar cane bagasse by using Hansen's solubility parameters. Thus, a new and optimized sphere of solubility for sugar cane bagasse lignin was determined, with δ D = 21.42 MPa 1/2 , δ P = 8.57 MPa 1/2 , δ H = 21.80 MPa 1/2 and R o = 13.56. It was observed that this new lignin sphere of solubility allowed a linear correlation between the solvent/ solute distance and the delignification extent data (linear regression coefficient of 0.93856). These results indicate that the Hansen solubility parameters can be used as a tool for choosing the solvent for an effective delignification of lignocellulosic raw materials.

Mild thermolytic solvolysis of technical lignins in polar organic solvents to a crude lignin oil

“…% at 350 °C. The formation of char at higher temperatures was also reported by Nielsen et al, 25 who analyzed by 13 33 The RED and Hansen solubility parameters of the tested solvents are listed in Table 2. Figure 3a shows the correlation between the RED and the yield of solubilized lignin for the investigated solvents.…”

“…A useful parameter for comparing two substances is the solubility parameter distance (R a ), based on their respective HSP components (Equation 4). 33 It is obvious that solubility, or high affinity, requires R a <R 0 , so a RED (Relative Energy Difference) number is often used to quantify distances R a relative to the interaction radius R 0 , as shown in equation 5. 30 (4) = 4( -…”

“…Thus, it is important to assume specific values for HSP in function of the source of the lignin. In our study, we performed solubility experiments with L4 (lignin from wheat straw).Accordingly, we will use a specific set of values of HSP for sugar cane bagasse lignin as determined by Novo et al33 Lignins from sugar cane (as well as lignins from grasses i.e. wheat straw) are classified as HGS lignin and contain more p-hydroxy phenyl moieties including p-coumarates and ferulates 35.…”

Isolation of Low Dispersity Fractions of Acetone Organosolv Lignins to Understand their Reactivity: Towards Aromatic Building Blocks for Polymers Synthesis

“…To calculate the RED between the lignins and the tested solvents, it is necessary to know the HSPs of lignins. Several values from the literature [42][43][44] were used to calculate the RED, and the results are presented in the Supporting Information ( Figure S4). However, they do not show any correlation with the solubility, as already experienced previously with softwood Kraft lignin.…”

“…However, they do not show any correlation with the solubility, as already experienced previously with softwood Kraft lignin. [22] The reported HSPs of lignin were calculated for softwood [42] and sugarcane bagasse lignin, [44] respectively. Given the structural differences between lignins from various botanical origins and extraction processes, significant differences in HSPs might be expected.…”