Dependence of cellulose dissolution in quaternary ammonium-based ionic liquids/DMSO on the molecular structure of the electrolyte

Autor(es)

Kostag, Marc ^[1] ; El Seoud, Omar A. ^[1]

Afiliação do(s) autor(es)

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

• Tipo de documento: Artigo Científico
• Fonte: Carbohydrate Polymers; v. 205, p. 524-532, FEB 1 2019.
• Citações Web of Science: 4

Resumo

We synthesized a series of quaternary ammonium acetates (QAAcOs) and assessed their solutions in DMSO as cellulose solvents. NBz111AcO/DMSO did not dissolve cellulose; substitution of its methyl groups resulted in efficient cellulose solvents; NBz31AcO/DMSO dissolved cellulose with difficulty. We attribute the inefficiency of both QAAcOs to: strong anion-cation interactions, NBz111AcO; steric effects and cation-cation hydrophobic interactions, NBz31AcO. Using isothermal titration calorimetry, we determined the enthalpies (H-E) of QAAcO (endothermic) dissolution, and QAAcO/cellobiose (exothermic) interactions; both in dimethyl sulfoxide/acetonitrile. The ratios of H-E are 5.34:1:1.45, for NB111AcO, NA12Bz1AcO, and NBz31AcO, respectively, i.e., dissolution of the first and third QAAcO in the solvent requires more energy. The corresponding ratios for QAAcO interaction with cellobiose are: 0.74:1:0.79, i.e., the second QAAcO interacts more strongly with cellobiose. This order of solvent efficiency is corroborated by SEM images of regenerated cotton linters. Light scattering showed that dissolved cellulose can be regenerated as nanoparticles by dialysis. {[}GRAPHICS] . (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: 16/22869-7 - Novos solventes na química da celulose: síntese, propriedades e aplicações de eletrólitos quaternários de amônio para a dissolução, regeneração e derivatização de celulose
• Beneficiário: Marc Kostag
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado