Review of the application of ionic liquids as solvents for chitin

2012 ◽  
Vol 32 (2) ◽  
Author(s):  
Malgorzata M. Jaworska ◽  
Tomasz Kozlecki ◽  
Andrzej Gorak
Keyword(s):  
Fourier Transform ◽  
Ionic Liquids ◽  
Microwave Irradiation ◽  
Infrared Spectra ◽  
Elevated Temperatures ◽  
Great Promise ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Crystallinity ◽  
Diffraction Patterns

Abstract Chitin is one of the most abundant biopolymers, but due to its high crystallinity, it is completely insoluble in most organic and inorganic solvents. Chitin is soluble only in solvents that can destroy intersheet and intrasheet H-bonds, and many of these solvents are toxic, corrosive, nondegradable, or mutagenic. Because of these drawbacks, there is a search for more environmentally friendly solvents for chitin. It has been shown that ionic liquids (ILs) can dissolve chitin at elevated temperatures (80°–110°C) or with application of microwave irradiation. The highest solubility of chitin in an IL was about 20% (1-ethyl-3-methylimidazolium acetate), whereas chitin was shown to be insoluble in 1-allyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium formate. Dissolved chitin can be regenerated by mixing with water or methanol, where the polymer precipitates from the solution. X-ray diffraction patterns of native polymer and precipitates have been compared and only small changes in crystallinity have been observed. In addition, Fourier transform infrared spectra remained similar for both forms of chitin, native and regenerated. Presented data hold great promise for the improvement of the chemistry of chitin and open new routes for chemical and enzymatic modifications of this polymer.

scholarly journals Regioselective Approach to Characterizing Increased Edge Availability in Layered Crystal Materials following Layer Expansion: Reaction of Kaolinite with Octadecyltrimethylammonium Salts

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 588
Author(s):  
Shingo Machida ◽  
Ken-ichi Katsumata ◽  
Atsuo Yasumori
Keyword(s):  
Fourier Transform ◽  
Mass Loss ◽  
Nitrogen Content ◽  
Infrared Spectra ◽  
Layered Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermogravimetric Curve ◽  
Diffraction Patterns ◽  
The Fourier Transform

In this paper, the regioselective reactions of kaolinite and methoxy-modified kaolinite (MeO-Kaol), methanol-expanded kaolinite, with octadecyltrimethylammonium salts are compared. This study mainly concerns the reactions of kaolinite or MeO-Kaol with octadecyltrimethylammonium chloride (C18TAC) in methanol and the subsequent exhaustive washing of the resultant products with ethanol. X-ray diffraction patterns of the products reveal no intercalation of C18TAC between pristine kaolinite layers. Additionally, intercalation and subsequent deintercalation of C18TAC proceed in the product using MeO-Kaol. In the Fourier-transform infrared spectra, the intensities of CH2 stretching bands of the product prepared using MeO-Kaol drastically increase compared to those using kaolinite. In addition, CH2 stretching bands of the product using kaolinite are hardly observed without enlarging the spectrum. The product using MeO-Kaol also displays mass loss in the range of 200–300 °C in the thermogravimetric curve and a nitrogen content with 0.15 mass% estimated using the CHN analysis. These results therefore demonstrate an increase in the available reactive edges in the layered crystal material following an expansion of the stacked layers.

Infrared spectroscopic study of the YPO4-YCrO4 system

1985 ◽  
Vol 50 (10) ◽  
pp. 2139-2145
Author(s):  
Alexander Muck ◽  
Eva Šantavá ◽  
Bohumil Hájek
Keyword(s):  
Spectroscopic Study ◽  
Infrared Spectra ◽  
Point Of View ◽  
Mixed Crystals ◽  
Crystal Symmetry ◽  
Infrared Spectroscopic Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Spectroscopic ◽  
Diffraction Patterns

The infrared spectra and powder X-ray diffraction patterns of polycrystalline YPO4-YCrO4 samples are studied from the point of view of their crystal symmetry. Mixed crystals of the D4h19 symmetry are formed over the region of 0-30 mol.% YPO4 in YCrO4. The Td → D2d → D2 or C2v(GS eff) correlation is appropriate for both PO43- and CrO43- anions.

Dissolution and Regeneration of Reed Leaf Fibers in Imidazole-Based Ionic Liquids

2013 ◽  
Vol 652-654 ◽  
pp. 1539-1542
Author(s):  
Hou Jie Zhao ◽  
Chun Yan Wei ◽  
Yong Zhu Cui ◽  
Li Hua Lv ◽  
Xiao Wang
Keyword(s):  
Fourier Transform ◽  
Ionic Liquids ◽  
Infrared Spectroscopy ◽  
Chloride Solution ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
X Ray ◽  
High Temperature And Pressure ◽  
Ft Ir ◽  
Temperature And Pressure

In this paper, regeneration of reed leaf fibers that have been degummed pretreatment in high temperature and pressure dissolved in 1-butyl-3-methylimidazolium chloride ionic liquids was studied. The samples containing 5% or 10%(wt/wt)reed leaf fibers in the ionic liquids, at 90°C for 7h.The dissolution process was viewed by polarizing microscope. Fourier-transform infrared spectroscopy(FT-IR) and X-ray diffraction were used to visualize the crystalline of reed leaf fiber transformed completely from cellulose I to cellulose Ⅱ after regenerated directly from 1-butyl-3-methylimidazolium chloride solution.

New complete assignment of X-ray powder diffraction patterns in graphitic carbon nitride using discrete Fourier transform and direct experimental evidence

2017 ◽  
Vol 19 (38) ◽  
pp. 26072-26084 ◽  
Author(s):  
Bo-wen Sun ◽  
Hong-yu Yu ◽  
Yong-jing Yang ◽  
Hui-jun Li ◽  
Cheng-yu Zhai ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Experimental Evidence ◽  
Powder Diffraction ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complete Assignment ◽  
Diffraction Patterns ◽  
Xrd Patterns

To date, there have been only a few studies focusing on the assignment of X-ray diffraction (XRD) patterns in graphitic carbon nitrides (g-C3N4) and contradictory determination for a broad peak around 12°–14° has been perplexing.

scholarly journals Chromium (III) Oxide Nanostructures Synthesized from Vernonia Amygdalina Leaves Extract

2020 ◽  
Vol 10 (1) ◽  
pp. 1856-1861
Keyword(s):  
Fourier Transform ◽  
Average Crystallite Size ◽  
Fourier Transform Infrared ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Vernonia Amygdalina ◽  
Sem Images ◽  
X Ray ◽  
Chloride Hexahydrate ◽  
Diffraction Patterns

This contribution reports first time synthesis of Cr2O3 nanostructures from chromium (III) chloride hexahydrate precursor using Vernonia amygdalina leaves extract as a reducing and stabilizing agent. Powder X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy techniques were used to study the structural and morphological properties of the as-synthesized Cr2O3 nanostructures. Powder X-ray diffraction patterns spectral analysis showed that hexagonal Cr2O3 nanostructures with an average crystallite size of 23.4 nm were synthesized with the minor appearance of CrO2. SEM images showed that the synthesized nanomaterials are granules. Fourier-transform infrared spectra represent a sharp absorption band at 552 cm-1, which indicates Cr-O-Cr vibrational and stretching modes.

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