UV-visible spectral analysis for the characterization of the titanium(iv)–4-(2-pyridylazo)resorcinol complex as a reagent for determining hydrogen peroxide

2020 ◽  
Vol 49 (3) ◽  
pp. 690-696
Author(s):  
Kiyoko Takamura ◽  
Takatoshi Matsumoto
Keyword(s):  
Hydrogen Peroxide ◽  
Spectral Analysis ◽  
Uv Visible

Titanium(iv)–4-(2-pyridylazo)resorcinol (Ti–PAR) has been effectively used for the determination of hydrogen peroxide.

Synthesis and Characterization of New Dibenzo[b, e]Thiepine Derivatives. I

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Camelia Elena Stecoza ◽  
Miron Teodor Caproiu ◽  
Constantin Draghici ◽  
Corina Ilie ◽  
Ileana Cornelia Chirita
Keyword(s):  
Hydrogen Peroxide ◽  
Spectral Analysis ◽  
Benzoic Acid ◽  
Potassium Salt ◽  
Polyphosphoric Acid ◽  
Chemical Characterization ◽  
Synthesis And Characterization ◽  
Acid Chlorides ◽  
New Compounds

The aim of the present paper was the synthesis and chemical characterization of some original compounds with dibenzo[b,e]thiepine structure. The synthesis of the new compounds was performed in several stages. Thus, by reaction of phtalide with thiophenol potassium salt, we obtained the 2-phenylthiomethyl-benzoic acid. The acid was cyclized with polyphosphoric acid to the desired 6,11-dihydrodibenzo[b,e]thiepin-11(6H)-one, converted afterwards to the corresponding oxime and subsequently to the O-acyloximino-dibenzo[b,e]thiepins by acylation with various substituted benzoic acid chlorides. The oxidation of O-acyloximino-dibenzo[b,e]thiepins with hydrogen peroxide afforded the corresponding sulfones. The new compounds, four O-acyl-oximino-dibenzo[b,e]thiepins, and four O-acyl-oximino-dibenzo[b,e]thiepin-5,5-dioxides, have been characterized by their physical constants (melting point, solubility) and their structures and purity were confirmed by elemental analysis, and spectral analysis (IR, 1H-NMR, 13C-NMR).

On the Characteristics of Bifurcation and Nonlinear Dynamic Response

2004 ◽  
Vol 126 (4) ◽  
pp. 574-579 ◽  
Author(s):  
Baozhong Yang ◽  
C. Steve Suh
Keyword(s):  
Spectral Analysis ◽  
Dynamic Response ◽  
Amplitude Modulation ◽  
Frequency Modulation ◽  
Instantaneous Frequency ◽  
Dynamic Instability ◽  
Spectral Component ◽  
The Individual

Spectral analysis has been widely applied to the detection of bifurcation and the determination of the extent to which dynamic instability and chaotic responses develop. However, because spectral analysis employs stationary sinusoids in representing time-varying signals of inherent nonlinearity, the use of Fourier domain methodologies would inexorably risk misinterpreting the true characteristics and obscuring the underlying physics of the nonlinear system being investigated. The fact that the amplitude and frequency of all the individual spectral component of a nonlinear, nonstationary dynamic response are modulated and coupled in time necessarily implies that, if the inception and transition of a bifurcated state of unstable motion is to be fully characterized, amplitude modulation and frequency modulation need to be temporally decoupled. The fundamental notion of instantaneous frequency defines frequency as the temporal gradient of phase and thus provides a powerful mechanism through which amplitude modulation and frequency modulation can be disassociated. Results of applying instantaneous frequency to the characterization of bifurcation and evolution of instability for a cracked rotor also indicate that instantaneous frequency interprets nonlinear rotary responses with sound physical bases.

Concerning the Application of FT-IR to the Study of Coal: A Critical Assessment of Band Assignments and the Application of Spectral Analysis Programs

1981 ◽  
Vol 35 (5) ◽  
pp. 475-485 ◽  
Author(s):  
Paul C. Painter ◽  
Randy W. Snyder ◽  
Michael Starsinic ◽  
Michael M. Coleman ◽  
Deborah W. Kuehn ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Aromatic Ring ◽  
Curve Fitting ◽  
Critical Assessment ◽  
Extinction Coefficients ◽  
Quantitative Measurements ◽  
Ft Ir ◽  
The Relationship

The problems associated with the application of FT-IR to the characterization of coal structure are critically discussed. The controversies concerning band assignments are considered and it is concluded that the strong 1600 cm−1 band can be assigned to an aromatic ring stretching mode that in most coals is intensity enhanced by the presence of phenolic groups. The application of computer routines to the determination of OH and CH groups is considered. Established criteria for curve fitting are applied to the problem. Qualitative identification of functional groups is achieved, but consistent quantitative measurements will require a determination of the relationship between the extinction coefficients of resolved bands.

scholarly journals Characterization of Cu(II)-ACC Complexes and Conversion of the Bound ACC into Ethylene in the Presence of Hydrogen Peroxide. Detection of a Brown Intermediate at Low Temperature

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Wadih Ghattas ◽  
Michel Giorgi ◽  
Christian Gaudin ◽  
Antal Rockenbauer ◽  
Marius Réglier ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Low Temperature ◽  
Absorption Band ◽  
Acc Oxidase ◽  
Optimum Activity ◽  
Hydrogen Peroxide Detection ◽  
Crystallographic Structures ◽  
Uv Visible ◽  
Reaction In Water

Two copper(II)-ACC complexes were prepared and characterized: [Cu(bpy)(ACC)(H2O)]⋅CO4(1) and[Cu(ACC)2]3⋅4H2O(2). Their crystallographic structures are described and analyzed. Spectroscopic characterizations (UV-visible and EPR) confirm that the structure is maintained in solution. These complexes are able to produce ethylene in the presence of hydrogen peroxide in an “ACC Oxidase-like” reaction in water and in methanol. The conversion of ACC into ethylene depends on the amount of base, and, in methanol, 3 equivalents of NaOH are needed for optimum activity. The base is proposed to play a role inH2O2deprotonation. The presence of an exogenic ligand (bpy) is important for the reactivity and may stabilize a reaction intermediate. Indeed, a brown intermediate with an absorption band centered at 433 nm can be detected at low temperature when1is treated with 10 equivalents ofH2O2.

scholarly journals HEMI-SYNTHESIS AND UV-VISIBLE SPECTROPHOTOMETRIC CHARACTERIZATION OF 2,4-DINITROPHENYLHYDRAZONES DERIVED FROM CITRAL AND CITRONELLAL ESSENTIAL OILS OF TWO AROMATIC PLANTS ACCLIMATIZED IN CONGO-BRAZZAVILLE

2021 ◽  
Vol 9 (03) ◽  
pp. 581-593
Author(s):  
Ndzeli Likibi Belline ◽  
◽  
Loubaki Milandou Laurent ◽  
Nsikabaka Samuel ◽  
Ouamba Jean-Maurille ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Essential Oils ◽  
Eucalyptus Citriodora ◽  
Easy Method ◽  
Uv Visible ◽  
Congo Brazzaville ◽  
High Level ◽  
Short Time

The orange-yellow and colorless essential oils with respective yields of 1.54% and 3.59% were extracted from the dry leaves of Cymbopogoncitratus (DC.) Stapf and Eucalyptus citriodora Hook. collected south of Brazzaville. Analysis by gas chromatography (GC) and by gas chromatography coupled with mass spectrometry (GC/MS) allowed the identification of fifteen (15) and eight (8) constituents representing (96.25%) and (98.46%) of total essential oils respectively. Cymbopogoncitratus oil consists mainly of geranial (51.99%) and neral (32.94%), two geometric isomers constituting citral which occupies a rate of 84.93%. While citronellal with a high level of (80.72%) and citronellol (10.48%) are the major compounds of the essential oil of Eucalyptus citriodora. Geranial (citral a) and citronellal 2,4-dinitrophenylhydrazones were hemi-synthesized by a simple, easy method, respectively from essential oils of Cymbopogoncitratus and Eucalyptus citriodora with respective conversion rate (yields) of 20%. and 37%, in a short time (three to five minutes). Analysis of geranial and citronellal 2,4-dinitrophenylhydrazones by UV-visible spectrophotometry showed maximum absorption wavelengths of 390 nm and 370 nm respectively. The UV-visible spectrophotometric method employed for the determination of these hydrazones is convenient, fast and simple. The hemi-synthesized hydrazones could be useful in the pharmaceutical industry, in perfumery, cosmetic and in biomedicine.

scholarly journals PHYTOCHEMICAL AND ANTIOXIDANT CHARACTERIZATION OF THINNED IMMATURE CITRUS UNSHIU FRUITS

2017 ◽  
Vol 9 (12) ◽  
pp. 293 ◽  
Author(s):  
Ji Hye Kim ◽  
Min Young Kim
Keyword(s):  
Free Radicals ◽  
Natural Antioxidants ◽  
Total Phenolic ◽  
Citrus Unshiu ◽  
Mass Detection ◽  
Uv Visible ◽  
Phytochemical Profile ◽  
Citrus Extract

Objective: We aimed to evaluate the characterization of thinned immature Citrus unshiu fruits with regard to their phytochemical profile and antioxidant capacity.Methods: Determination of total phenolic, flavonoid, and carotenoid and ascorbic acid contents was done by UV-Visible spectrophotometry, whereas UPLC-mass detection was used for the analysis of individual flavanone (naringin, hesperidin, hesperetin, neohesperedine and narirutin) and flavonol (rutin). In addition, free radicals (DPPH, O2-, H2O2 and NO) scavenging assays were used to determine the antioxidant capacity.Results: Naringin, hesperidine, neohesperedine and narirutin were the main flavanones in all thinned immature Citrus unshiu fruits. The contents of total phenolic, flavonoid and carotenoid were more prevalent in immature fruits than the level found in mature fruits. All thinned immature Citrus unshiu fruits possess an evident antioxidant capacity. The immature Citrus extract concentrations providing 50% inhibition (IC50) for free radicals; 1.2-1.49 mg/ml for DPPH, 1.03-1.46 mg/ml for superoxide, 1.95-3.43 mg/ml for hydrogen peroxide and 1.64-3.45 mg/ml for nitric oxide was lower than those of mature Citrus extracts.Conclusion: Thinned immature Citrus unshiu fruits could be an economic and readily accessible source of natural antioxidants and as a possible food and pharmaceutical supplement.

Preparation and characterization of hexamethylenetetramine N-oxide and some acid adducts

1978 ◽  
Vol 31 (6) ◽  
pp. 1249 ◽  
Author(s):  
Y Lam ◽  
TCW Mak
Keyword(s):  
Hydrogen Peroxide ◽  
Molar Ratio ◽  
Ethanolic Solution ◽  
Aqueous Hydrogen Peroxide ◽  
X Ray ◽  
Space Groups ◽  
Unit Cells ◽  
Crystalline Adduct

Hexamethylenetetramine N-oxide (4) was isolated from the reaction of hexamethylenetetramine (1) with 30% aqueous hydrogen peroxide. With the two reactants in molar ratio 1 : 2, a 1 : 1 : 1 crystalline adduct (5) of (4) with hydrogen peroxide and water was obtained at temperatures around 10°C, and a 1 : 1 adduct (6) of (4) with formic acid upon warming the reaction mixture to above 30°C. Information pertaining to the nature of compounds (4), (5) and (6) was derived from p.m.r, and X-ray determination of unit cells and space groups. Several 1 : 1 acid adducts similar to (6) were prepared by adding the corresponding acid to an ethanolic solution of (4).

scholarly journals Synthesis, Characterization and In Silico Study of Fe(III) Complex with N'-(4-Chlorobenzoyl)-Isonicotino-Hydrazide as Anti Tuberculosis Candidate

2020 ◽  
Vol 6 (1) ◽  
pp. 70-81
Author(s):  
Ruswanto Ruswanto ◽  
Fajar Setiawan ◽  
Nur Rahayuningsih ◽  
Richa Mardianingrum ◽  
Nur Laili Dwi Hidayati ◽  
...  
Keyword(s):  
Free Energy ◽  
Melting Point ◽  
Acyl Carrier Protein ◽  
Synthesis Method ◽  
Carrier Protein ◽  
Infrared Spectrophotometry ◽  
In Silico Study ◽  
Uv Visible

The synthesis of Fe(III) complexes with ligands N'-(4-Chlorobenzoyl)isonicotinohydrazide can be synthesized through mixing metal and ligand dissolved in ethanol by reflux at ± 75oC for 5 hours. The instruments for the characterization of the complex were used UV-Visible and Infrared Spectrophotometry. The aims of the study are: to determine the synthesis method, characterize of the complex, and to study the interaction of the complex with target receptors. The weight of the synthesized compound was obtained by 38.1 mg. The purity of the complex has been tested using the determination of melting point and got a melting point range was 196-198oC. The maximum wavelength of Fe(III)N'-(4-Chlorobenzoyl)isonicotinohydrazid) complex was  261.0 nm and provide absorption of Fe-O vibrations at wavenumbers 530.42 cm-1. The docking process was done using AutodockTools-1.5.6 software which shows that the Fe(III)N'-(4-Chlorobenzoyl) isonicotinohydrazide complex can interact with Enoyl-Acyl Carrier Protein Reductase from Mycobacterium Tuberculosis and it has better  interaction than isoniazid or N'-(4-Chlorobenzoyl)isonicotinohydrazide compound with the acquisition of free energy binding (ΔG) -9.80 kcal/mol and inhibition constant (Ki ) 0.06529 μM.

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