A mechanistic insight into the organocatalytic properties of imidazolium-based ionic liquids and a positive co-solvent effect on cellulose modification reactions in an ionic liquid

Kakuchi, Ryohei; Itô, Ryo; Nomura, Seiichi; Abroshan, Hadi; Ninomiya, Kazuaki; Ikai, Tomoyuki; Maeda, Katsuhiro; Kim, Hyung J.; Takahashi, Kenji

doi:10.1039/c6ra28659c

Cited by 42 publications

(48 citation statements)

References 52 publications

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“…In contrast to Kakuchi et al (2015Kakuchi et al ( , 2017, in [DBNH][OAc] no additional base or activation was required to obtain excellent reactivity. As the IL is derived from the conjugation of a superbase (DBN) and acetic acid, traces of superbase (from equilibration) likely contribute to catalyzing the reaction.…”

Section: Resultsmentioning

confidence: 99%

“…The reason for such result is TBAF, which deacetylates the cellulose esters regioselectively from the positions of 2 and 3 (Zheng et al 2013 ), compared with our system (0.5-1 h). Reaching high DS often requires high temperature, 80-110°C, long reaction times 3-24 h (Kakuchi et al 2015), catalyst (Luan et al 2013) or co-solvent (Jogunola et al 2016;Kakuchi et al 2017;Rinaldi 2011;Schenzel et al 2014;Xu et al 2013). Lower temperatures have also been reported but the reaction time has been 24 h and the product produced had a low DS of 0.64 (Wu et al 2004).…”

Section: Resultsmentioning

confidence: 99%

“…Notably, the side-product of the acetylation reaction with IpeAc is acetone which is easy to evaporate from the synthesis mixture and does not usually introduce side reactions. The same group have just recently published an article, where [Emim][OAc] and other imidazolium based ionic liquids were used in DMSO mixtures for assessment of the mechanistic effects of ILs (Kakuchi et al 2017). Vinyl esters can also be used in cellulose esterification reactions, as an acylation reagent, but have been used in ''traditional'' solvents with catalysts or activators (Chen et al 2016;Ç etin et al 2009;Heinze et al 2003;Jebrane et al 2011;Jebrane and Sebe 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Typical co-solvents include dimethyl sulfoxide (DMSO) (Kakuchi et al 2017;Xu et al 2013) or dimethylacetamide (DMA) (Rinaldi 2011), but acetonitrile (ACN) (Nawaz et al 2014) and acetone (Jogunola et al 2016) have also been used. However, having an additional co-solvent may actually complicate the workup and recovery of all components.…”

Section: Introductionmentioning

confidence: 99%

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Homogenous esterification of cellulose pulp in [DBNH][OAc]

2017

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Cellulose acetate is widely used in films, filters, textiles, lacquer and cosmetic products. Herein we demonstrate the production of cellulose esters under homogeneous conditions using 1,5-diazabicyclo[4.3.0]non-5-ene acetate ([DBNH][OAc]) as solvent. The reagents have been chosen such that the system is recyclable, i.e. by-products are low boiling and easy to remove. It is demonstrated that cellulose acetate can be synthesized with different degree of substitution (DS) values, and that some commonly used acylation regents, like vinyl carboxylates react well without additional base catalyst. Low to high DS values are possible with good recovery of high purity ionic liquid (IL). A linear correlation method of two separate methods, IR and 31 P NMR, is proposed to reliably assess the DS of the products. The recyclability of the solvent is demonstrated by acetylating cellulose with isopropenyl acetate to high degree and regeneration into water. After regeneration of cellulose acetate from the IL with addition of water, the residual water was entrained using n-butanol to minimize hydrolysis of [DBNH][OAc], to allow for high recovery and high purity of the ionic liquid. Thus, an overall scheme for batch cellulose acetylation and recovery of [DBNH][OAc] from aqueous solutions is proposed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Homogenous esterification of cellulose pulp in [DBNH][OAc]

2017

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“…When compared to CA films, the added oleic acid acted as a self‐plasticizer for CA leading to lower T g and melting point, ductile material properties, and even reducing both the oxygen and water vapor permeability . It should additionally be noted that ILs can also be effectively used in the field of derivatization, serving as reaction media for cellulose modification . Recently, homogenous esterification was performed in an ionic liquid.…”

Section: Lignocellulosic Biomassmentioning

confidence: 99%

Natural Polymers from Biomass Resources as Feedstocks for Thermoplastic Materials

Müller

Zollfrank

Schmid

2019

Macro Materials & Eng

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With the objective of a more sustainable circular economy, one long‐term goal is the utilization of renewable resources as feedstock for the production of polymer‐based materials. In order to successfully process such materials using existing industrial‐scale technologies or even recycling processes, the natural polymers must have thermoplastic properties. With only a few exceptions, natural polymers are not thermoplastic. However, chemical and physical modification techniques are able to induce thermoplasticity in natural polymers from biomass resources such as cellulose, lignin, and chitin. Modification techniques focus on masking the hydroxyl groups to disrupt dense hydrogen bonding and so enable polymer chain mobility upon heating. The introduction of long alkyl chains into the polymer backbone effectively improves the thermoplastic processing of natural polymers. With regard to polymer blending, chemical grafting and graft copolymerization are powerful tools for enhancing compatibility. For both chemical and physical modification, solvents such as ionic liquids and deep eutectic solvents are currently being explored for biomass and fiber processing and show promise for the future development of thermoplastic biopolymers. This review describes possible modifications, potential processing difficulties, and gives a summary of relevant studies described in the scientific literature.

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Interphase Engineering of a Cellulose‐Based Carbon Fiber Reinforced Composite by Applying Click Chemistry

et al. 2018

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Given our possible future dependence on carbon fiber reinforced composites, the introduction of a renewable matrix might be advantageous for the vision of a sustainable world. Cellulose is a superior green candidate and provides exceptional freedom in composite design as the free OH groups can be conveniently functionalized to give tailor‐made materials. To obtain a high‐performing carbon fiber reinforced cellulose propionate composite, we accurately tailored the interfacial adhesion by invoking click chemistry. The synthetic strategy involved grafting of a phenylacetylene structure onto the carbon fiber surface, onto which O‐acylated 6‐azido‐6‐deoxycellulose and a number of aromatic azides could be covalently attached. Single‐fiber fragmentation tests indicated that the lipophilicity and size of the substituent on the deposited structure played a crucial role in determining molecular entanglement and mechanical interlocking effects, as penetration into the cellulose propionate matrix was of utmost importance. Enhanced interfacial shear strength was obtained for the carbon fiber covalently functionalized with the cellulose derivative. Nevertheless, the greatest increase was observed for the derivative substituted with a compact and highly lipophilic CF3 substituent. In a broader sense, our study provides a synthetic platform to bind cellulose derivatives to graphitic surfaces and paves the ways towards the preparation of innovative cellulose‐based carbonaceous materials.

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A mechanistic insight into the organocatalytic properties of imidazolium-based ionic liquids and a positive co-solvent effect on cellulose modification reactions in an ionic liquid

Abstract: Mechanistic insights into organocatalytic properties of imidazolium-based ionic liquids led to improvements of cellulose modification reactions in ionic liquids.

Cited by 42 publications

References 52 publications

Homogenous esterification of cellulose pulp in [DBNH][OAc]

Homogenous esterification of cellulose pulp in [DBNH][OAc]

Natural Polymers from Biomass Resources as Feedstocks for Thermoplastic Materials

Interphase Engineering of a Cellulose‐Based Carbon Fiber Reinforced Composite by Applying Click Chemistry

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