Non-covalent interactions in bmimCl/co-solvent mixtures: a FTIR spectroscopy and computational study

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F19%3A00504639" target="_blank" >RIV/61389013:_____/19:00504639 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0167732219301898?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0167732219301898?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.molliq.2019.04.092" target="_blank" >10.1016/j.molliq.2019.04.092</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Non-covalent interactions in bmimCl/co-solvent mixtures: a FTIR spectroscopy and computational study

Popis výsledku v původním jazyce

Ionic liquids such as 1-butyl-3-methylimidazolium chloride (bmimCl) are efficient solvents for cellulose, but high viscosity of the resulting solutions hampers further cellulose shaping and derivatization. To solve this problem, mixtures of ILs with various organic co-solvents are often employed in place of neat ILs. So far, the intermolecular interactions in such mixtures are poorly understood, which hinders further development of this class of cellulose solvents. In this work, we utilized infrared spectroscopy (IR) and quantum chemical model calculations to study the intermolecular interactions in differently concentrated mixtures of bmimCl with two typical co-solvents, dimethyl sulfoxide (DMSO) and N,N-dimethylacetamide (DMAc). First, we refined the assignment of the relevant characteristic bands in the IR spectra of the individual mixture components. This then helped us to reveal that bmim+-DMSO and bmim+-DMAc associates, stabilized by hydrogen bonds between the imidazolium ring CH groups and oxygens of DMSO or DMAc, are formed in the studied mixtures. Importantly, only a relatively small fraction of co-solvent molecules (up to ca. 20 mol% for DMSO and ca. 45 mol% for DMAc) are involved in the associate formation, leaving a large proportion of bmimCl molecules non-solvated. While the maximum co-solvent concentration at which direct cellulose dissolution can be achieved is considerably different for DMSO and DMAc, the corresponding molar ratio of bmimCl to interacting co-solvent molecules was the same for both the studied systems (about 2.5:1). We propose that this ratio might be related to the critical size of bmimCl clusters necessary for achieving cellulose dissolution. Furthermore, increasing the temperature from 25 to 80 °C resulted in a significantly decreased fraction of interacting solvent molecules for bmimCl/DMSO but not for bmimCl/DMAc. This indicates that the comparatively lower tendency of DMSO to form associates with bmimCl is due to the lower strength of the underlying hydrogen bond. The results of this study illustrate how intermolecular interactions influence the macroscopic performance of different IL-based solvent systems.

Název v anglickém jazyce

Non-covalent interactions in bmimCl/co-solvent mixtures: a FTIR spectroscopy and computational study

Popis výsledku anglicky

Ionic liquids such as 1-butyl-3-methylimidazolium chloride (bmimCl) are efficient solvents for cellulose, but high viscosity of the resulting solutions hampers further cellulose shaping and derivatization. To solve this problem, mixtures of ILs with various organic co-solvents are often employed in place of neat ILs. So far, the intermolecular interactions in such mixtures are poorly understood, which hinders further development of this class of cellulose solvents. In this work, we utilized infrared spectroscopy (IR) and quantum chemical model calculations to study the intermolecular interactions in differently concentrated mixtures of bmimCl with two typical co-solvents, dimethyl sulfoxide (DMSO) and N,N-dimethylacetamide (DMAc). First, we refined the assignment of the relevant characteristic bands in the IR spectra of the individual mixture components. This then helped us to reveal that bmim+-DMSO and bmim+-DMAc associates, stabilized by hydrogen bonds between the imidazolium ring CH groups and oxygens of DMSO or DMAc, are formed in the studied mixtures. Importantly, only a relatively small fraction of co-solvent molecules (up to ca. 20 mol% for DMSO and ca. 45 mol% for DMAc) are involved in the associate formation, leaving a large proportion of bmimCl molecules non-solvated. While the maximum co-solvent concentration at which direct cellulose dissolution can be achieved is considerably different for DMSO and DMAc, the corresponding molar ratio of bmimCl to interacting co-solvent molecules was the same for both the studied systems (about 2.5:1). We propose that this ratio might be related to the critical size of bmimCl clusters necessary for achieving cellulose dissolution. Furthermore, increasing the temperature from 25 to 80 °C resulted in a significantly decreased fraction of interacting solvent molecules for bmimCl/DMSO but not for bmimCl/DMAc. This indicates that the comparatively lower tendency of DMSO to form associates with bmimCl is due to the lower strength of the underlying hydrogen bond. The results of this study illustrate how intermolecular interactions influence the macroscopic performance of different IL-based solvent systems.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

<a href="/cs/project/GA17-03810S" target="_blank" >GA17-03810S: Vliv nekovalentních interakcí na mísitelnost celulózy se syntetickými polymery v komplexních rozpouštědlech</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Molecular Liquids

ISSN

0167-7322

e-ISSN

—

Svazek periodika

285

Číslo periodika v rámci svazku

1 July

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

9

Strana od-do

688-696

Kód UT WoS článku

000472698800074

EID výsledku v databázi Scopus

2-s2.0-85064908096