Acylation of cellulose in a novel solvent system: Solution of dibenzyldimethylammonium fluoride in DMSO

作者：Casarano Romeu; Pires Paulo A R; El Seoud Omar A^*

来源：Carbohydrate Polymers, 2014, 101: 444-450.

DOI：10.1016/j.carbpol.2013.09.043

• Cellulose acylation
• Dibenzyldimethylammonium fluoride-hydrate
• Molecular dynamics
• Tetra(1-butyl)ammonium fluoride-hydrate

A novel electrolyte, dibenzyldimethylammonium fluoride has been obtained essentially anhydrous (BMAF-0.1 H2O) by a simple route. Its thermal stability, relative to tetra(1-butyl)ammonium fluoride trihydrate (TBAF-3H(2)O) has been demonstrated by thermogravimetric analysis. DMSO solution of (BMAF-0.1H(2)O) dissolves microcrystalline- and fibrous celluloses; the dissolved biopolymers have been acylated by ethanoic-, butanoic-, and hexanoic anhydride. The degrees of substitution of the esters are higher than with TBAF-3H(2)O/DMSO. The reasons are discussed in terms of differences in electrolyte structure and contents of water of hydration, whose presence leads to side reactions and decreases of the basicity of (F-). This conclusion is corroborated by molecular dynamics simulations of the interactions of glucose dodecamer/R4NF-hydrate/DMSO. These show that the interactions oligomer-F--water is operative only for TBAF-3H(2)O/DMSO. The efficiency of BMAF-0.1H(2)O/DMSO is explained based on better accessibility of the biopolymer due to efficient hydrogen-bonding between its hydroxyl groups and the essentially desolvated (F-).

• 出版日期2014-1-30