Novel synthesis of hydroxyvinylethyl xylan using 4-vinyl-1,3-dioxolan-2-one

Akil, Youssef; Lehnen, Ralph; Saake, Bodo

doi:10.1016/j.tetlet.2016.08.009

Cited by 7 publications

(4 citation statements)

References 18 publications

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“…[44] Aliphatic OH groupsa re more prone to attack the carbonyl group, leading to the formation of ac arbonate linkage(Scheme 1b). [44] Aliphatic OH groupsa re more prone to attack the carbonyl group, leading to the formation of ac arbonate linkage(Scheme 1b).…”

Section: Introductionmentioning

confidence: 99%

“…In the case of VEC, the form Ai sp referred because of the steric hindrance and the + +Ie ffect of the vinyl group, which causes ar educed reactivity of the correspondingc arbon toward electrophilicr eactions. [44] Aliphatic OH groupsa re more prone to attack the carbonyl group, leading to the formation of ac arbonate linkage(Scheme 1b). [41] However,as imilar pathway as for phenolic OH groups, with the loss of CO 2 and the formation of an ether linkage, is also possible.…”

Section: Introductionmentioning

confidence: 99%

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Solvent‐ and Halogen‐Free Modification of Biobased Polyphenols to Introduce Vinyl Groups: Versatile Aromatic Building Blocks for Polymer Synthesis

Duval

Avérous

2017

ChemSusChem

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Various biobased polyphenols (lignins and condensed tannins) were derivatized with vinyl ethylene carbonate, a functional cyclic carbonate, to obtain multifunctional aromatic polymers bearing vinyl groups. The reaction was optimized on a condensed tannin and soda lignin. In both cases, full conversion of the phenol groups was achieved in only 1 h at 150 °C without solvent and with K CO as a cheap and safe catalyst. This reaction was later applied to other condensed tannins and technical lignins (Kraft and organosolv), showing only little dependence on the chemical structure of the polyphenols. The obtained derivatives were thoroughly characterized by H and P NMR spectroscopy, FTIR spectroscopy, and size-exclusion chromatography. The developed method was compared with previously published protocols for the introduction of vinyl groups on lignin, and shows promising advances toward the modification of biobased polyphenols according to green chemistry principles. The obtained macromolecules show great potential as highly versatile biobased aromatic building blocks for the synthesis of polymers through, for example, radical, metathesis, or thiol-ene reactions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Solvent‐ and Halogen‐Free Modification of Biobased Polyphenols to Introduce Vinyl Groups: Versatile Aromatic Building Blocks for Polymer Synthesis

Duval

Avérous

2017

ChemSusChem

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“…Steric hindrance reduces the reactivity of the substituted carbon (C4), leading to a greater amount of structures of type A. In addition, electron-donating substituents, such as CH 3 and CHCH 2 , reduce the electrophilicity of C4, further leading preferentially to structures of type A . In contrast, electron-withdrawing substituents, such as CH 2 OH, favor structures of type B by increasing the electrophilicity of C4.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, electron-donating substituents, such as CH 3 and CHCH 2 , reduce the electrophilicity of C4, further leading preferentially to structures of type A. 53 In contrast, electron-withdrawing substituents, such as CH 2 OH, favor structures of type B by increasing the electrophilicity of C4. This explains the higher proportion of structures of type B measured with GC, even though the substituent was bulkier than for PC.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Cyclic Carbonates as Safe and Versatile Etherifying Reagents for the Functionalization of Lignins and Tannins

Duval

Avérous

2017

ACS Sustainable Chem. Eng.

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The potential of cyclic carbonates for the functionalization of lignins and condensed tannins was studied in detail. Four different cyclic carbonates, namely, ethylene, propylene, vinyl ethylene, and glycerol carbonates, were evaluated. Full conversion of the phenolic hydroxyl groups was observed within very short reaction times (less than 2 h and as low as 15 min with ethylene carbonate). Comparison among the different cyclic carbonates shows that the substituent influences the reactivity as follows: CH3 < CHCH2 < CH2OH < H. The developed method is a safe alternative to the use of organohalides or epoxides for the introduction of functional groups of interest onto lignins and tannins. The prepared derivatives expose primary or secondary hydroxyl groups, vinyl groups, 1,2- and 1,3-diols, or five-membered cyclic carbonates. All of the derivatives have an enhanced thermal stability and a lowered glass transition temperature (T g) compared to the neat lignins and condensed tannins and thus present a high potential for the preparation of various types of biobased and aromatic polymers. The proposed method also allows the grafting of oligomeric chains when the reaction time is extended and thus represents an alternative to the use of the toxic and hazardous ethylene or propylene oxides for the oxyalkylation of polyphenols.

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Hydroxyalkylation of xylan using propylene carbonate: comparison of products from homo- and heterogeneous synthesis by HRMAS NMR and rheology

et al. 2017

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International audienceXylan is a highly available polysaccharide in the plant kingdom and is therefore a valuable resource for novel materials from renewable resources. Hydroxyalkylation is one of the most common reactions to derivatize biopolymers by altering hydroxyl groups. State of the art procedures incorporate epoxides, which are toxic, carcinogenic and highly explosive. In this study, hydroxyalkylation with propylene carbonate (PC) was used as green approach to synthesize xylan derivatives. Reaction pathways under homogeneous conditions, in dimethyl sulfoxide (DMSO), and heterogeneous conditions, without solvent, are compared. Analysis using liquid state and high resolution magic angle spinning (HRMAS) NMR, a novel approach for insoluble but swellable polysaccharide derivatives, as well as FTIR spectroscopy, hydrolysis in combination with borate anion exchange chromatography, and rheology showed significant differences regarding the structure of the products. While the degree of substitution (DS) is similar under both conditions, side chains are significantly longer under heterogeneous conditions, implying a higher rate of homopolymerization. This leads to a non-complete decarboxylation. The higher sterical hindrance imposed by longer side chains therefore leads to a higher tendency of xylose monosaccharides being derivatized at only one native hydroxyl group, while under homogeneous conditions a higher tendency towards double substitution can be observed. Rheology showed a shear thinning behaviour as well as an increase in viscosity with DS for samples from homogeneous synthesis. Products from solvent-free approach were analyzed in swollen state. They showed gel-like behaviour, whose elasticity increases with increasing DS as a result of side chain entanglement

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Novel synthesis of hydroxyvinylethyl xylan using 4-vinyl-1,3-dioxolan-2-one

Cited by 7 publications

References 18 publications

Solvent‐ and Halogen‐Free Modification of Biobased Polyphenols to Introduce Vinyl Groups: Versatile Aromatic Building Blocks for Polymer Synthesis

Solvent‐ and Halogen‐Free Modification of Biobased Polyphenols to Introduce Vinyl Groups: Versatile Aromatic Building Blocks for Polymer Synthesis

Cyclic Carbonates as Safe and Versatile Etherifying Reagents for the Functionalization of Lignins and Tannins

Hydroxyalkylation of xylan using propylene carbonate: comparison of products from homo- and heterogeneous synthesis by HRMAS NMR and rheology

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