Horseradish peroxidase-catalyzed formation of hydrogels from chitosan and poly(vinyl alcohol) derivatives both possessing phenolic hydroxyl groups

2014 ◽  
Vol 111 ◽  
pp. 404-409 ◽  
Author(s):  
Shinji Sakai ◽  
Mehdi Khanmohammadi ◽  
Ali Baradar Khoshfetrat ◽  
Masahito Taya
Keyword(s):  
Horseradish Peroxidase ◽  
Vinyl Alcohol ◽  
Phenolic Hydroxyl ◽  
Poly Vinyl Alcohol ◽  
Hydroxyl Groups ◽  
Phenolic Hydroxyl Groups

scholarly journals The Synthesis of Poly(Vinyl Alcohol) Grafted with Fluorinated Protic Ionic Liquids Containing Sulfo Functional Groups

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4158
Author(s):  
Patrycja Glińska ◽  
Andrzej Wolan ◽  
Wojciech Kujawski ◽  
Edyta Rynkowska ◽  
Joanna Kujawa
Keyword(s):  
Ionic Liquids ◽  
Vinyl Alcohol ◽  
Proton Exchange ◽  
Polymer Materials ◽  
Polymerization Reaction ◽  
Poly Vinyl Alcohol ◽  
Hydroxyl Groups ◽  
Protic Ionic Liquids ◽  
Synthesis Route ◽  
Sulfo Groups

There has been an ongoing need to develop polymer materials with increased performance as proton exchange membranes (PEMs) for middle- and high-temperature fuel cells. Poly(vinyl alcohol) (PVA) is a highly hydrophilic and chemically stable polymer bearing hydroxyl groups, which can be further altered. Protic ionic liquids (proticILs) have been found to be an effective modifying polymer agent used as a proton carrier providing PEMs’ desirable proton conductivity at high temperatures and under anhydrous conditions. In this study, the novel synthesis route of PVA grafted with fluorinated protic ionic liquids bearing sulfo groups (–SO3H) was elaborated. The polymer functionalization with fluorinated proticILs was achieved by the following approaches: (i) the PVA acylation and subsequent reaction with fluorinated sultones and (ii) free-radical polymerization reaction of vinyl acetate derivatives modified with 1-methylimidazole and sultones. These modifications resulted in the PVA being chemically modified with ionic liquids of protic character. The successfully grafted PVA has been characterized using 1H, 19F, and 13C-NMR and FTIR-ATR. The presented synthesis route is a novel approach to PVA functionalization with imidazole-based fluorinated ionic liquids with sulfo groups.

Methylation of Phenolic Hydroxyl Group and Demethylation of Anisoles

2009 ◽  
Vol 2009 (4) ◽  
pp. 229-230 ◽  
Author(s):  
Nobuhiro Sato ◽  
Hiroyuki Endo
Keyword(s):  
Microwave Heating ◽  
Room Temperature ◽  
Reverse Reaction ◽  
Phenolic Hydroxyl ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Phenolic Hydroxyl Groups ◽  
Phenyl Ethers ◽  
Methyl Phenyl

A mild methylation of phenolic hydroxyl groups with iodomethane was enabled in the presence of sodium bis(trimethylsilyl)amide at room temperature. The reverse reaction, namely demethylation of methyl phenyl ethers, was easily achieved by microwave heating with neat iodotrimethylsilane.

Fast, Easy, and Economical Quantification of Lignin Phenolic Hydroxyl Groups: Comparison with Classical Techniques

2018 ◽  
Vol 32 (5) ◽  
pp. 5969-5977 ◽  
Author(s):  
Luis Serrano ◽  
Esakkiammal Sudha Esakkimuthu ◽  
Nathalie Marlin ◽  
Marie-Christine Brochier-Salon ◽  
Gerard Mortha ◽  
...  
Keyword(s):  
Phenolic Hydroxyl ◽  
Hydroxyl Groups ◽  
Phenolic Hydroxyl Groups

scholarly journals Gallic Acid and Quercetin as Intelligent and Active Ingredients in Poly(vinyl alcohol) Films for Food Packaging

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1999 ◽  
Author(s):  
Francesca Luzi ◽  
Elisa Pannucci ◽  
Luca Santi ◽  
José Maria Kenny ◽  
Luigi Torre ◽  
...  
Keyword(s):  
Gallic Acid ◽  
Vinyl Alcohol ◽  
Food Packaging ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Casting Process ◽  
Poly Vinyl Alcohol ◽  
Hydroxyl Groups ◽  
Active Ingredients

Gallic acid (GA) and quercetin (QC) were used as active ingredients in poly(vinyl alcohol) (PVA) film formulations obtained by solvent casting process. The effect of two different percentages (5 and 10 % wt.) on morphological behavior, thermal stability, optical, mechanical, and release properties of PVA were investigated, while migration with food stimulants and antioxidant properties were tested taking into account the final application as food packaging systems. The results showed how different dispersability in PVA water solutions gave different results in term of deformability (mean value of ε PVA/5GA = 280% and ε PVA/5QC = 255%, with 190% for neat PVA), comparable values for antioxidant activity at the high contents (Radical Scavenging Activity, RSA(%) PVA/10GA = 95 and RSA(%) PVA/10QC = 91) and different coloring attitude of the polymeric films. It was proved that GA, even if it represents the best antioxidant ingredient to be used with PVA and can be easily dispersed in water, it gives more rigid films in comparison to QC, that indeed was more efficient in tuning the deformability of the PVA films, due the presence of sole hydroxyl groups carrying agent. The deviation of the film coloring towards greenish tones for GA films and redness for QC films after 7 and within 21 days in the simulated conditions confirmed the possibility of using easy processable PVA films as active and intelligent films in food packaging.

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