Cellulose Dissolution in Mixtures of Ionic Liquids and Dimethyl Sulfoxide: A Quantitative Assessment of the Relative Importance of Temperature and Composition of the Binary Solvent

Autor(es)

Dignani, Marcella T. ^[1] ; Bioni, Thais A. ^[1] ; Paixao, Thiago R. L. C. ^[1] ; El Seoud, Omar A. ^[1]

Afiliação do(s) autor(es)

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

• Tipo de documento: Artigo Científico
• Fonte: Molecules; v. 25, n. 24 DEC 2020.
• Citações Web of Science: 0

Resumo

We studied the dissolution of microcrystalline cellulose (MCC) in binary mixtures of dimethyl sulfoxide (DMSO) and the ionic liquids: allylbenzyldimethylammonium acetate; 1-(2-methoxyethyl)-3-methylimidazolium acetate; 1,8-diazabicyclo {[}5.4.0]undec-7-ene-8-ium acetate; tetramethylguanidinium acetate. Using chemometrics, we determined the dependence of the mass fraction (in %) of dissolved cellulose (MCC-m%) on the temperature, T = 40, 60, and 80 degrees C, and the mole fraction of DMSO, chi(DMSO) = 0.4, 0.6, and 0.8. We derived equations that quantified the dependence of MCC-m% on T and chi(DMSO). Cellulose dissolution increased as a function of increasing both variables; the contribution of chi(DMSO) was larger than that of T in some cases. Solvent empirical polarity was qualitatively employed to rationalize the cellulose dissolution efficiency of the solvent. Using the solvatochromic probe 2,6-dichloro-4-(2,4,6-triphenylpyridinium-1-yl)phenolate (WB), we calculated the empirical polarity E-T(WB) of cellobiose (a model for MCC) in ionic liquid (IL)-DMSO mixtures. The E-T(WB) correlated perfectly with T (fixed chi(DMSO)) and with chi(DMSO) (fixed T). These results show that there is ground for using medium empirical polarity to assess cellulose dissolution efficiency. We calculated values of MCC-m% under conditions other than those employed to generate the statistical model and determined the corresponding MCC-m% experimentally. The excellent agreement between both values shows the robustness of the statistical model and the usefulness of our approach to predict cellulose dissolution, thus saving time, labor, and material. (AU)

• 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
• 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: 19/16491-0 - Detecção rápida e em campo de metais tóxicos combinando sensores eletroquímicos baseados em papel e voltametria cíclica de varredura rápida
• Beneficiário: Thiago Regis Longo Cesar da Paixão
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/08782-1 - Sensores químicos miniaturizados e integrados: novas plataformas de fabricação para aplicações biológicas, clínicas e ambientais
• Beneficiário: Mauro Bertotti
• Modalidade de apoio: Auxílio à Pesquisa - Temático