Synthesis of Polyanionic Cellulose Carbamates by Homogeneous Aminolysis in an Ionic Liquid/DMF Medium

Abstract

Polyanionic cellulose carbamates were synthesized by rapid and efficient homogeneous aminolysis of cellulose carbonate half-esters in an ionic liquid/DMF medium. Cellulose bis-2,3-O-(3,5-dimethylphenyl carbamate), as a model compound, reacted with different chloroformates to cellulose carbonates. These intermediates were subjected to aminolysis, for which both the reactivity of different chloroformates towards C6-OH and the reactivity/suitability of the respective carbonate half-ester in the aminolysis were comprehensively studied. Phenyl chloroformate and 4-chlorophenyl chloroformate readily reacted with C6-OH of the model cellulose derivative, while 4-nitrophenyl chloroformate did not. The intermediate 4-chlorophenyl carbonate derivative with the highest DS (1.05) was then used to evaluate different aminolysis pathways, applying three different amines (propargyl amine, β-alanine, and taurine) as reactants. The latter two zwitterionic compounds are only sparingly soluble in pure DMF as the typical reaction medium for aminolysis; therefore, several alternative procedures were suggested, carefully evaluated, and critically compared. Solubility problems with β-alanine and taurine were overcome by the binary solvent system DMF/[EMIM]OAc (1:1, v/v), which was shown to be a promising medium for rapid and efficient homogeneous aminolysis and for the preparation of the corresponding cellulose carbamate derivatives or other compounds that are not accessible by conventional isocyanate chemistry. The zwitterionic cellulose carbamate derivatives presented in this work could be promising chiral cation exchangers for HPLC enantiomer separations.

Immobilization of a cellulose carbamate-type chiral selector onto silica gel by alkyne-azide click chemistry for the preparation of chiral stationary chromatography phases

“…The higher reactivity and selectivity of phenyl chloroformate towards C6-OH versus C2-OH and C3-OH have already been reported (Elschner et al 2014;Ganske and Heinze 2018). In a previous study, we have optimized the protocol towards quantitative oxycarbonylation of C6-OH (Bui et al 2022b) and also reported on the optimization and successful aminolysis reaction between the polysaccharidic carbonates (Bui et al 2022a). The obtained phenyl carbonate served as a reactive intermediate for subsequent aminolysis with propargylamine yielding a propynyl carbamate moiety as an alkyne donor for immobilization of the CS onto 3-azidopropyl-functionalized silica gel (Fig.…”

Impact of Eco-Friendly Drilling Additives on Foaming Properties for Sustainable Underbalanced Foam Drilling Applications

“…In this study, the effects of drilling additives, namely, polyanionic cellulose (PAC), carboxymethyl cellulose (CMC) polymers, and starch, on foaming stability were examined. These additives were specifically chosen for their environmentally friendly characteristics as they are derived from renewable and natural sources. − …”

Optimization of the regioselective synthesis of mixed cellulose 3,5-dimethylphenyl and α-phenylethyl carbamate selectors as separation phases for chiral HPLC

“…Cellulose derivative 5 was synthesized by oxycarbonylation of C6-OH of cellulose derivative 4 with phenyl chloroformate to prepare a precursor, which subsequently was to be converted into cellulose derivatives 6R and 6S by carbonate aminolysis. Phenyl chloroformate was chosen as a reagent due to its higher reactivity compared to p-nitrophenyl chloroformate (Bui et al 2022c;Bui et al 2022a). FTIR and solid-state 13 C NMR spectra of cellulose derivatives 5 versus 4 are shown in Fig.…”

“…Carbonate aminolysis was shown to be an efficient path towards the introduction of carbamate functionalities onto cellulose (Elschner et al 2013;Ganske and Heinze 2018;Bui et al 2022c), besides the routinely used isocyanate chemistry (Hearon et al 1943a;Hearon et al 1943c;Heard and Suedee 1996;Khan et al 2008;Labafzadeh et al 2014). However, the former way offers higher flexibility due to the greater availability of amines compared to the rather limited choice of available isocyanates.…”

“…However, the former way offers higher flexibility due to the greater availability of amines compared to the rather limited choice of available isocyanates. Different phenyl chloroformates have been evaluated as reagents for cellulose aryl carbonate synthesis (Ganske and Heinze 2018;Bui et al 2022c), which were shown to be more reactive than the respective alkyl carbonates (Elschner and Heinze 2015). For details on carbonate aminolysis for obtaining cellulose carbamates see the comprehensive studies by Heinze et al and others (Pourjavadi et al 2011;Elschner et al 2013;Elschner and Heinze 2015;Ganske and Heinze 2018;Bui et al 2022c).…”