2 research outputs found
Directed discovery of greener cosolvents:new cosolvents for use in ionic liquid based organic electrolyte solutions for cellulose dissolution
Cellulose is an abundant,
cheap, renewable, yet recalcitrant, material,
which, if dissolved, may be formed into a wide range of materials,
composites, and mixtures. Much attention has recently been focused
on the use of mixtures of ionic liquids and some solvents (so-called
organic electrolyte solutions, OESs) as efficient cellulose dissolution
solvents, but many of the cosolvents used lack green credentialsa
perennial problem where dipolar aprotic solvents are the solvents
of choice. We present a rational approach, based on definition of
ranges of solvent parameters gathered together in recently published
databases, to find “greener” cosolvents for OES formation.
Thus, γ-butyrolactone is identified as a suitable OES former
for dissolution of microcrystalline cellulose and biobased γ-valerolactone
as a marginally less efficient, but significantly safer, alternative.
Comparison of cosolvent efficiency reveals that previous use of measures
of mass, or concentration, of cellulose dissolved may have masked
the similarities between 1-methylimidazole, dimethyl sulfoxide (DMSO), <i>N,N</i>-dimethylformamide, <i>N-N</i>′-dimethylimidazolidinone, <i>N,N</i>-dimethylacetamide, <i>N</i>-methylpyrrolidinone,
and sulfolane (seldom considered), while comparison on a molar basis
reveals that the molar volume of the solvent is an important factor.
Reference-interaction site model (RISM) calculations for the DMSO/1-ethyl-3-methylimidazolium
acetate OES suggest competition between DMSO and the acetate anion
and preferential solvation of cellulose by the ionic liquid