Theoretical and experimental study of guar gum sulfation

Kazachenko, Аleksandr S.; Akman, Feride; Sagaama, Abir; Issaoui, Noureddine; Malyar, Yuriy N.; Vasilieva, Natalya; Borovkova, Valentina S.

doi:10.1007/s00894-020-04645-5

Cited by 66 publications

(26 citation statements)

References 37 publications

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“…This is also indicated by the change in the crystallinity index calculated from the Segal formula, which decreases in the series 0.73 (DEAE-cellulose) > 0.53 (SDEAE1) > 0.21 (SDEAE2). The observed phenomenon is consistent with the literature data, according to which the use of the SAA/U deep eutectic solvent leads to the stronger amorphization of polysaccharides than sulfation in organic solvents …”

Section: Resultsmentioning

confidence: 99%

Sulfation of Diethylaminoethyl-Cellulose: QTAIM Topological Analysis and Experimental and DFT Studies of the Properties

et al. 2021

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Sulfated cellulose derivatives are biologically active substances with anticoagulant properties. In this study, a new sulfated diethylaminoethyl (DEAE)-cellulose derivative has been obtained. The effect of a solvent on the sulfation process has been investigated. It is shown that 1,4-dioxane is the most effective solvent, which ensures the highest sulfur content in DEAE-cellulose sulfate under sulfamic acid sulfation. The processes of sulfamic acid sulfation in the presence of urea in 1,4-dioxane and in a deep eutectic solvent representing a mixture of sulfamic acid and urea have been compared. It is demonstrated that the use of 1,4-dioxane yields the sulfated product with a higher sulfur content. The obtained sulfated DEAE-cellulose derivatives have been analyzed by Fourier transform infrared spectroscopy, X-ray diffractometry, and scanning electron and atomic force microscopy, and the degree of their polymerization has been determined. The introduction of a sulfate group has been confirmed by the Fourier transform infrared spectroscopy data; the absorption bands corresponding to sulfate groups have been observed in the ranges of 1247–1256 and 809–816 cm–1. It is shown that the use of a deep eutectic solvent leads to the side carbamation reactions. Amorphization of DEAE-cellulose during sulfation has been demonstrated using X-ray diffractometry. The geometric structure of a molecule in the ground state has been calculated using the density functional theory with the B3LYP/6-31G(d, p) basis set. The reactive areas of DEAE-cellulose and its sulfated derivatives have been analyzed using molecular electrostatic potential maps. The thermodynamic parameters (heat capacity, entropy, and enthalpy) of the target sulfation products have been determined. The HOMO–LUMO energy gap, Mulliken atomic charges, and electron density topology of the title compound have been calculated within the atoms in molecule theory.

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Section: Resultsmentioning

confidence: 99%

Sulfation of Diethylaminoethyl-Cellulose: QTAIM Topological Analysis and Experimental and DFT Studies of the Properties

et al. 2021

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“…In the analysis of the charge transfer interactions, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and the corresponding energies are of great importance [ 65 ]. The HOMO and LUMO frontier molecular orbitals of a molecular system are conventionally used to estimate its chemical reactivity [ 66 , 67 ].…”

Section: Resultsmentioning

confidence: 99%

“…The HOMO and LUMO frontier molecular orbitals of a molecular system are conventionally used to estimate its chemical reactivity [ 66 , 67 ]. The HOMO can donate an electron, while the LUMO is considered to be an electron acceptor due to its ability to gain an electron [ 65 ]. At the occurrence of a chemical reaction in a molecular system, electrons pass through the HOMO–LUMO gap due to the energy change [ 68 ].…”

Section: Resultsmentioning

confidence: 99%

Sulfation of Wheat Straw Soda Lignin with Sulfamic Acid over Solid Catalysts

et al. 2022

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Soda lignin is a by-product of the soda process for producing cellulose from grassy raw materials. Since a method for the industrial processing of lignin of this type is still lacking, several research teams have been working on solving this problem. We first propose a modification of soda lignin with sulfamic acid over solid catalysts. As solid catalysts for lignin sulfation, modified carbon catalysts (with acid sites) and titanium and aluminum oxides have been used. In the elemental analysis, it is shown that the maximum sulfur content (16.5 wt%) was obtained with the Sibunit-4® catalyst oxidized at 400 °C. The incorporation of a sulfate group has been proven by the elemental analysis and Fourier-transform infrared spectroscopy. The molecular weight distribution has been examined by gel permeation chromatography. It has been demonstrated that the solid catalysts used in the sulfation process causes hydrolysis reactions and reduces the molecular weight and polydispersity index. It has been established by the thermal analysis that sulfated lignin is thermally stabile at temperatures of up to 200 °C. According to the atomic force microscopy data, the surface of the investigated film consists of particles with an average size of 50 nm. The characteristics of the initial and sulfated β-O-4 lignin model compounds have been calculated and recorded using the density functional theory.

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“…It is known [23,43,[55][56][57][58][59] that sulfation of polysaccharides leads to greater amorphization of their structure. Thus, the data shown in Figure 6 are in good agreement with the literature.…”

Section: X-ray Diffractions Analysismentioning

confidence: 99%

“…In the process of sulfation, an increase in the amorphization of the initial xanthan structure was observed, which was manifested by a decrease in the intensity in X-ray diffraction patterns from 17° to 50° 2θ. It is known [23,43,[55][56][57][58][59] that sulfation of polysaccharides leads to greater amorphization of their structure. Thus, the data shown in Figure 6 are in good agreement with the literature.…”

Section: X-ray Diffractions Analysismentioning

confidence: 99%

Food Xanthan Polysaccharide Sulfation Process with Sulfamic Acid

Kazachenko

Vasilieva

Borovkova

et al. 2021

Foods

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Xanthan is an important polysaccharide with many beneficial properties. Sulfated xanthan derivatives have anticoagulant and antithrombotic activity. This work proposes a new method for the synthesis of xanthan sulfates using sulfamic acid. Various N-substituted ureas have been investigated as process activators. It was found that urea has the greatest activating ability. BBD of xanthan sulfation process with sulfamic acid in 1,4-dioxane has been carried out. It was shown that the optimal conditions for the sulfation of xanthan (13.1 wt% sulfur content) are: the amount of sulfating complex per 1 g of xanthan is 3.5 mmol, temperature 90 °C, duration 2.3 h. Sulfated xanthan with the maximum sulfur content was analyzed by physicochemical methods. Thus, in the FTIR spectrum of xanthan sulfate, in comparison with the initial xanthanum, absorption bands appear at 1247 cm−1, which corresponds to the vibrations of the sulfate group. It was shown by GPC chromatography that the starting xanthan gum has a bimodal molecular weight distribution of particles, including a high molecular weight fraction with Mw > 1000 kDa and an LMW fraction with Mw < 600 kDa. It was found that the Mw of sulfated xanthan gum has a lower value (~612 kDa) in comparison with the original xanthan gum, and a narrower molecular weight distribution and is characterized by lower PD values. It was shown by thermal analysis that the main decomposition of xanthan sulfate, in contrast to the initial xanthan, occurs in two stages. The DTG curve has two pronounced peaks, with maxima at 226 and 286 °C.

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Theoretical and experimental study of guar gum sulfation

Cited by 66 publications

References 37 publications

Sulfation of Diethylaminoethyl-Cellulose: QTAIM Topological Analysis and Experimental and DFT Studies of the Properties

Sulfation of Diethylaminoethyl-Cellulose: QTAIM Topological Analysis and Experimental and DFT Studies of the Properties

Sulfation of Wheat Straw Soda Lignin with Sulfamic Acid over Solid Catalysts

Food Xanthan Polysaccharide Sulfation Process with Sulfamic Acid

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