Crystallographic characterization of ethylammonium salts of tetracyanopyridine (TCPy) and fluorescence determination of the degree of substitution of the amino nitrogen atom thereof

CrystEngComm ◽  
2019 ◽  
Vol 21 (36) ◽  
pp. 5500-5507 ◽  
Author(s):  
Oleg V. Ershov ◽  
Sergey S. Chunikhin ◽  
Mikhail Yu. Ievlev ◽  
Mikhail Yu. Belikov ◽  
Viktor A. Tafeenko
Keyword(s):  
Nitrogen Atom ◽  
Amino Nitrogen ◽  
Degree Of Substitution ◽  
Amino Nitrogen Atom ◽  
Fluorescence Determination ◽  
Substitution Degree

Luminescence determination of the substitution degree of the amino nitrogen atom using ethylamine, diethylamine, triethylamine and tetraethylammonium has been shown.

On the potential role of the amino nitrogen atom as a hydrogen bond acceptor in macromolecules

1998 ◽  
Vol 279 (5) ◽  
pp. 1123-1136 ◽  
Author(s):  
Ben Luisi ◽  
Modesto Orozco ◽  
Jiri Sponer ◽  
Francisco J Luque ◽  
Zippora Shakked
Keyword(s):  
Hydrogen Bond ◽  
Nitrogen Atom ◽  
Potential Role ◽  
Amino Nitrogen ◽  
Hydrogen Bond Acceptor ◽  
Amino Nitrogen Atom

Synthesis and optical properties of chlorin monomer, dimer and trimer on an amino nitrogen atom

2015 ◽  
Vol 23 (17) ◽  
pp. 5972-5978 ◽  
Author(s):  
Hitoshi Tamiaki ◽  
Tomoaki Nagai ◽  
Takuya Tanaka ◽  
Tomohiro Tatebe
Keyword(s):  
Optical Properties ◽  
Nitrogen Atom ◽  
Amino Nitrogen ◽  
Amino Nitrogen Atom

scholarly journals Synthesis and Physicochemical Characterization of Undecylenic Acid Grafted to Hyaluronan for Encapsulation of Antioxidants and Chemical Crosslinking

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 35 ◽  
Author(s):  
Gloria Huerta-Ángeles ◽  
Martina Brandejsová ◽  
Kateřina Kopecká ◽  
František Ondreáš ◽  
Tomáš Medek ◽  
...  
Keyword(s):  
Light Scattering ◽  
Physicochemical Characterization ◽  
Degree Of Substitution ◽  
Size Exclusion ◽  
Molar Ratio ◽  
Chemical Crosslinking ◽  
Undecylenic Acid ◽  
Hydrophobic Moiety ◽  
Substitution Degree

In this work, a new amphiphilic derivative made of 10-undecylenic acid grafted to hyaluronan was prepared by mixed anhydrides. The reaction conditions were optimized, and the effect of the molecular weight (Mw), reaction time, and the molar ratio of reagents was explored. Using this methodology, a degree of substitution up to 50% can be obtained. The viscosity of the conjugate can be controlled by varying the substitution degree. The physicochemical characterization of the modified hyaluronan was performed by infrared spectroscopy, Nuclear Magnetic Resonance, Size-Exclusion Chromatography combined with Multiangle Laser Light Scattering (SEC-MALLS), and rheology. The low proton motility and self-aggregation of the amphiphilic conjugate produced overestimation of the degree of substitution. Thus, a novel method using proton NMR was developed. Encapsulation of model hydrophobic guest molecules, coenzyme Q10, curcumin, and α-tocopherol into the micellar core was also investigated by solvent evaporation. HA-UDA amphiphiles were also shown to self-assemble into spherical nanostructures (about 300 nm) in water as established by dynamic light scattering. Furthermore, HA-UDA was crosslinked via radical polymerization mediated by ammonium persulphate (APS/TEMED). The cross-linking was also tested by photo-polymerization catalyzed by Irgacure 2959. The presence of the hydrophobic moiety decreases the swelling degree of the prepared hydrogels compared to methacrylated-HA. Here, we report a novel hybrid hyaluronan (HA) hydrogel system of physically encapsulated active compounds and chemical crosslinking for potential applications in drug delivery.

Fluorous 1,2,3-Triazol-4-ylmethyl Amines and Amine Derivatives for Novel Surfactant Applications

2015 ◽  
Vol 68 (1) ◽  
pp. 57 ◽  
Author(s):  
Dominic V. Francis ◽  
Jason B. Harper ◽  
Roger W. Read
Keyword(s):  
Nitrogen Atom ◽  
Amino Nitrogen ◽  
Triazole Ring ◽  
Ring Systems ◽  
Amino Nitrogen Atom

A series of fluorous surfactants with additional functionality were generated through the attachment of substituents at the amino nitrogen atom of the surfactant moiety. Examples of molecules containing one and two triazole ring systems were synthesized through N-alkylation and N-acylation strategies.

Characterization of Carboxymethyl Cellulose (CMC) Synthesized from Microcellulose of Cassava Peel

2021 ◽  
Vol 57 (4) ◽  
pp. 225-235
Author(s):  
Suripto D. Yuwono ◽  
Endah Wahyuningsih ◽  
Noviany ◽  
Agung A. Kiswandono ◽  
Wasinton Simanjuntak ◽  
...  
Keyword(s):  
Particle Size ◽  
Carboxymethyl Cellulose ◽  
Sem Analysis ◽  
Wave Number ◽  
H2so4 Solution ◽  
Substitution Degree ◽  
Cassava Peel ◽  
Weak Peak

In this study, carboxymethyl cellulose (CMC) was synthesized from the cellulose of cassava peel using alkalization and etherification reaction, and it was subsequently characterized with various techniques. Microcellulose was obtained by hydrolyzing a;-cellulose from cassava peel using H2SO4 with concentrations of 45%, 47%, and 49%. The experimental results indicate that the varying concentrations of acid affect the particle size of the cellulose, with 49% H2SO4 solution producing a cellulose with particle size of around 0.45-2.42 �m and relative percentage of 11.3% according to PSA analysis. Other analyses conducted included determination of substitution degrees, DTG/DTA/TGA, FTIR, SEM, and XRD. The value of the substitution degree was determined at 0.27. TGA decomposition thermograms at a temperature of 150oC-320oC of 19.60 % indicate CMC compounds. DTA thermograms show that these CMC compounds have endothermic properties at 140oC and exothermic properties at 260oC. FTIR spectra show the presence of absorption band at wave number 1605 cm-1, which is a characteristic absorption of carbonyl group bound to cellulose. The results of SEM analysis indicate that the CMC has a tenuous surface morphology, and the XRD diffractograms are marked by the presence of weak peak at 2e = 20o, implying the existence of CMC as mostly amorphous.

scholarly journals Sintesis dan Karakterisasi Selulosa Asetat (CA)

2018 ◽  
Vol 5 (2) ◽  
pp. 58-62
Author(s):  
Fensia Analda Souhoka ◽  
Jolantje Latupeirissa
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Cellulose Acetate ◽  
Acid Anhydride ◽  
Degree Of Substitution ◽  
Synthesis And Characterization ◽  
Cellulose Content

Synthesis and characterization of cellulose acetate (CA) has been conducted. The cellulose used in this study was commecial a-cellulose in 92% content. All the CA products were analyzed by FTIR spectrometers. The determination of cellulose content was done using standart method of TAPPI T-203, while the determination of the degree of substitution (DS) was based on SNI 0444:2009 method. Conventional acetylation of cellulose was performed using gacial acetic acid, anhydride acetic acid, and sulfuric acid. The acetylation at 25 °C for 2.5 hours gave the DS of 1.482 and at 40 °C for 5 hours gave the higher DS 2.295.

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