Acylation of Cellulose with N,N′‐Carbonyldiimidazole‐Activated Acids in the Novel Solvent Dimethyl Sulfoxide/Tetrabutylammonium Fluoride

Abstract

Summary: Carboxylic acids were efficiently activated with N,N′‐carbonyldiimidazole (CDI) and applied for the acylation of cellulose under homogeneous conditions using dimethyl sulfoxide (DMSO)/tetrabutylammonium fluoride trihydrate (TBAF) as solvent. The simple and elegant method is a very mild and easily applicable tool for the synthesis of pure aliphatic, alicyclic, bulky, and unsaturated cellulose esters with degrees of substitution of up to 1.9. Products are soluble in organic solvents, e.g., DMSO or N,N‐dimethylformamide (DMF). The cellulose esters were characterized by elemental analysis, FT‐IR, 1H and 13C NMR spectroscopy and show no impurities or substructures resulting from side reactions.

Ionic Liquid as Reaction Media for the Production of Cellulose-Derived Polymers from Cellulosic Biomass

“…Cellulose maintains its original chemical structure or forms a complex with the solvent only by intermolecular interactions (no covalent interactions occur) [63], thus, ILs are part of the so called non-derivatizing solvents [64] that include, for example, aqueous solution of sodium hydroxide [65], N,N-dimethylacetamide/lithium chloride (DMA/LiCl) [66,67], dimethylsulfoxide (DMSO) in combination with ammonium fluorides [68][69][70][71], and N-methylmorpholine-N-oxide (NMMO) [72]. There are a number of derivatizing solvents (able to dissolve cellulose with substitution, forming new covalent bonds) e.g., trifluoroacetic acid (TFA) [73], sodium hydroxide/carbon disulfide (NaOH/CS 2 ) [74], and N,N-dimethylformamide/dinitrogen tetroxide [75].…”

Direct Dissolution of Cellulose: Background, Means and Applications

“…NMR and GPC but also for homogenous reactions for chemical modification of cellulose, both in labscale only. Both etherifications and esterifications have been pursued with varying success [106][107][108][109][110]. TBAF is a very hygroscopic salt and water content in DMSO/TBAF/cellulose solutions may play a crucial role, depending on circumstances.…”

Tosylation and acylation of cellulose in 1-allyl-3-methylimidazolium chloride

“…An interesting pathway for cellulose ester preparation is homogeneous acylation after in situ activation of carboxylic acids with tosyl chloride Srokova et al 2004), N,N 0 -carbonyldiimidazole (CDI) (Hussain et al 2004) or N,N-dicyclohexylcarbodiimide (DCC) (Samaranayake and Glasser 1993). In the activation method, the acylation is carried out by an activated ester which is generated in situ from the corresponding carboxylic acid with an activating agent.…”

“…The nondegradative nature, lower viscosity, as well as the higher solubility of cellulose in [amim]Cl, prompted us to carry out the synthesis in this media. The majority of publications regarding the chemistry of cellulose have quoted the use of microcrystalline cellulose (Avicel Ò PH-101), which is relatively soluble into traditional cellulose solvents, such as DMSO/TBAF (Heinze et al 2000Liu and Baumann 2002;El Seoud et al 2000;Regiani et al 1999;Hussain et al 2004). In the present study, we have used microcrystalline cellulose as a starting material and optimised tosylation in a way that the DS close to 1 could be achieved in [amim]Cl, and thus avoid the use of protection group chemistry in subsequent nucleophilic displacement reactions.…”