Review of the application of ionic liquids as solvents for chitin (original) (raw)
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Modification of Chitin Particles with Ionic Liquids Containing Ethyl Substituent in a Cation
Advances in Materials Science and Engineering
Chitin cannot be dissolved in conventional solvents due to the strong inter- and intrasheet network of hydrogen bonds and the large number of crystalline regions. Some ionic liquids (ILs) have been suggested in the literature as possible solvents for chitin. Seven of them, all having an ethyl group as substituent in the cationic ring, have been tested in this work: [Emim][Cl], [Emim][Br], [Emim][I], [Emim][OAc], [Emim][Lact], [Epyr][I], and [EMS][BFSI]. Chitin was insoluble in [EMS][BFSI] while for all other ILs solubility was limited due to high viscosity of solutions and equilibria have not been reached. Changes in physical structure, particle size distribution, and crystallinity of recovered chitin depended on ionic liquid used. Increase in porosity was observed for chitin treated with [Emim][Cl], [Emim][I], [Emim][Br], and [Emim][Lact]; changes in particle size distribution were observed for [Emim][AcOH] and [EMS][BFSI]; increase in crystallinity was noticed for chitin treated w...
2020
Chitin is the second most abundant polysaccharide on the Earth after cellulose, therefore there is a tangible need for finding new environmentally-friendly solvents for the manufacture of useful forms of that polymer. Ionic liquids have been recently proposed as a possible type of solvent for chitin and cellulose. The possibility of the dissolution of chitin of various origin in six selected ionic liquids was investigated. Chitin samples were characterised by the main characteristic properties: degree of N-acetylation (by FTIR spectroscopy), degree of crystallinity (by WAXS), average molecular weight (by the viscometric method) and physical form. The studies performed allowed to find the optimum chitin-ionic liquid system based on 1-btyl-3-methylimidazolium acetate for the manufacture of chitin fibres by the solution blow spinning method. Final products were characterized by the same set of parameters as the initial materials.
Green Chemistry, 2017
An efficient conversion of chitin, the second most abundant renewable polymer on the Earth, into N-acetylglucosamine and N,N′-diacetylchitobiose, using room temperature ionic liquids (RTILs) and commercially available chitinases is described for the first time. The sequential strategy consists of the use of RTILs to pretreat chitin under mild conditions as a first step before enzymatic hydrolysis. [C2mim][OAc] (1-ethyl-3-methyl imidazolium) pretreatment provides an efficient production of N-acetylglucosamine (185.0 ± 4.0 mg per g chitin) or N,N′-diacetylchitobiose (667.60 ± 20.71 mg per g chitin) catalyzed by chitinase from Trichoderma viride or Streptomyces griseus, respectively. A thorough investigation of the structural changes of chitin induced by RTIL pretreatment suggested an increase in enzymes’ accessibility to the chitin substrate. Alternatively, a one-pot enzymatic hydrolysis of chitin in [C2mim][OAc]-aqueous medium constitutes a promising simultaneous route to selectively...
Polymers
Natural polymers are very widespread in the world, which is why it is so important to know about the possibilities of their use. Chitin is the second most abundant reproducible natural polymer in nature; however, it is insoluble in water and basic solvents. Chitin is an unused waste of the food industry, for which there are possibilities of secondary management. The research led to obtaining a soluble, environmentally friendly form of chitin, which has found potential applications in the many fields, e.g., medicine, cosmetics, food and textile industries, agriculture, etc. The deacetylated form of chitin, which is chitosan, has a number of beneficial properties and wide possibilities of modification. Modification possibilities mean that we can obtain chitosan with the desired functional properties, facilitating, for example, the processing of this polymer and expanding the possibilities of its application, also as biomimetic materials. The review contains a rich description of the p...
The influence of selected ionic liquids on activity of chitin deacetylase
Chemical and Process Engineering, 2016
Chitin deacetylase is the only known enzyme which is able to deacetylate N-acetyl-D-glucosamine units in chitin or chitosan chains. As chitin can hardly be dissolved in organic/inorganic solvents, new solvents are still searched. Ionic liquids are promising for that application and for homophase enzymatic deacetylation. The aim of the work was to investigate the influence of selected ionic liquids on activity of chitin deacetylase. It has been shown that [Amim] ionic liquids increase the activity of chitin deacetylase. The highest activity was observed for [Amim][Cl]. Ionic liquids with shorter (ethyl (C2)) and longer side chain (buthyl (C4)) only insignificantly influenced the activity of the enzyme. All tested ionic liquids with [Br] anion increased the activity of chitin deacetylase while the [Emim] and [Bmim] cation in combination with [Cl] anion inhibited the activity of the enzyme.