Understanding cellulose dissolution in ionic liquid-dimethyl sulfoxide binary mixtures: Quantification of the relative importance of hydrogen bonding and hydrophobic interactions

Autor(es)

El Seoud, Omar A. ^[1] ; Bioni, Thais A. ^[1] ; Dignani, Marcella T. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Chem, 748 Prof Lineu Prestes Av, BR-05508000 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF MOLECULAR LIQUIDS; v. 322, JAN 15 2021.
• Citações Web of Science: 0

Resumo

We studied the dissolution of microcrystalline cellulose (MCC) in mixtures of dimethyl sulfoxide (DMSO) with 32 ionic liquids (ILs), at a fixed temperature (70 degrees C) and mole fraction of DMSO (chi(DMSO) = 0.6). Under these conditions, employing a recommended dissolution protocol, MCC dissolved in 19 IL-DMSO mixtures. In order to access quantitatively the relative importance (to biopolymer dissolution) of cellulose-solvent interactions, we correlated the mass fraction of dissolved cellulose (MCC-m%) with physicochemical properties of these mixtures. The solvent descriptors that gave the best correlations are Lewis acidity and Lewis basicity (calculated from the UV-Vis spectra of solvatochromic probes), the molar volume of the IL, and the Lorentz-Lorenz refractive index function of the IL-DMSO mixtures. This result is similar to that observed when solvent empirical polarities of these binary mixtures were correlated with the same descriptors. The multi-parameter correlations quantify, for the first time, the relative importance of cellulose-solvent interactions. Our results agree with the established opinion that an efficient cellulose solvent should disrupt the inter- and intramolecular hydrogen bonding in cellulose, and the hydrophobic interactions present due to the amphiphilic nature of the biopolymer. (C) 2020 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 19/02928-7 - Líquidos iônicos (LIs) recicláveis na dissolução e regeneração de celulose: relação estrutura molecular/desempenho, e propriedades da celulose regenerada
• Beneficiário: Marcella Teixeira Dignani
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 14/22136-4 - Uso de solventes verdes e suas misturas na otimização de processos químicos
• Beneficiário: Omar Abou El Seoud
• Modalidade de apoio: Auxílio à Pesquisa - Temático