scholarly journals Spectroscopic Studies, Thermal Behaviour and Ac Impedance Study of Chemically Synthesized Silver Doped Polyaniline / BaFe12O19 Polymer Composite

2018 ◽  
Vol 7 (4.5) ◽  
pp. 20
Author(s):  
K. Vinay ◽  
K. Shivakumar ◽  
Y. T Ravikiran ◽  
M. Revanasiddappa
Keyword(s):  
Thermal Behaviour ◽  
Room Temperature ◽  
Interfacial Polymerization ◽  
Relaxation Mechanism ◽  
Spectroscopic Studies ◽  
Frequency Range ◽  
Impedance Response ◽  
Ft Ir ◽  
Doped Polyaniline

The present work is a study of a.c impedance response and thermal behaviour of IPANI/Ag/BaFe12O19 (PAB) composites synthesized by in-situ oxidative interfacial polymerization using (NH4)2S2O8 as an oxidizing agent at 0-50C. The synthesized polymer compo- sites were examined by FT-IR, TGA-DTA and DSC techniques. The a.c conductivity properties of the composites were investigated in the frequency range varying from 5x101 – 5x106 Hz at room temperature using HIOKI make 3532-50 LCR Hi-tester. FT-IR profiles confirm the formation of ferrite composite. The endothermic regions in the DTA pattern are consistent with the change regions in the TG curve. The Cole-Cole plots observed in the form of exact semi-circles clearly suggests the Debye-type relaxation mechanism present in these materials.  

scholarly journals Experimental and Theoretical Studies of Sonically Prepared Cu–Y, Cu–USY and Cu–ZSM-5 Catalysts for SCR deNOx

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 824
Author(s):  
Przemysław J. Jodłowski ◽  
Izabela Czekaj ◽  
Patrycja Stachurska ◽  
Łukasz Kuterasiński ◽  
Lucjan Chmielarz ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Ultrasonic Irradiation ◽  
Active Phase ◽  
Spectroscopic Studies ◽  
In Situ Drifts ◽  
Ft Ir ◽  
Diffuse Reflectance Infrared ◽  
Experimental And Theoretical Studies

The objective of our study was to prepare Y-, USY- and ZSM-5-based catalysts by hydrothermal synthesis, followed by copper active-phase deposition by either conventional ion-exchange or ultrasonic irradiation. The resulting materials were characterized by XRD, BET, SEM, TEM, Raman, UV-Vis, monitoring ammonia and nitrogen oxide sorption by FT-IR and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). XRD data confirmed the purity and structure of the Y/USY or ZSM-5 zeolites. The nitrogen and ammonia sorption results indicated that the materials were highly porous and acidic. The metallic active phase was found in the form of cations in ion-exchanged zeolites and in the form of nanoparticle metal oxides in sonochemically prepared catalysts. The latter showed full activity and high stability in the SCR deNOx reaction. The faujasite-based catalysts were fully active at 200–400 °C, whereas the ZSM-5-based catalysts reached 100% activity at 400–500 °C. Our in situ DRIFTS experiments revealed that Cu–O(NO) and Cu–NH3 were intermediates, also indicating the role of Brønsted sites in the formation of NH4NO3. Furthermore, the results from our experimental in situ spectroscopic studies were compared with DFT models. Overall, our findings suggest two possible mechanisms for the deNOx reaction, depending on the method of catalyst preparation (i.e., conventional ion-exchange vs. ultrasonic irradiation).

scholarly journals Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer
Keyword(s):  
Diffraction Analysis ◽  
Room Temperature ◽  
31P Nmr ◽  
Spectroscopic Studies ◽  
Iron Complex ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phosphenium Ions

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

scholarly journals Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by in-situ FT-IR Spectroscopy

2019 ◽  
Author(s):  
Xi Yang
Keyword(s):  
Ir Spectroscopy ◽  
Reaction Rate ◽  
Interfacial Polymerization ◽  
Reaction System ◽  
Reaction Rates ◽  
Water Permeation ◽  
Ft Ir ◽  
Trimesoyl Chloride ◽  
Ft Ir Spectroscopy

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize the nanofiltration (NF) membrane. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies are applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer; (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in-situ FT-IR spectroscopy was firstly used to monitor the IP reaction of PIP/TMC reaction system, with hydrophilic interlayers or macromolecular additives. Moreover, we study the formed polyamide layer growth on the substrate, in a real-time manner. The in-situ FT-IR experimental results confirm that the IP reaction rates are effectively suppressed and the formed polyamide thickness reduces from 138±24 nm to 46±2 nm. Furthermore, the optimized NF membrane with excellent performance are consequently obtained, which include the boosted water permeation flux about 141~238 (L·m2·h/MPa) and superior salt rejection of Na2SO4 > 98.4%.

The role of platinum on the NOx storage and desorption behavior of ceria: An online FT-IR study combined with in situ Raman and UV-Vis spectroscopy

2020 ◽  
Author(s):  
Anastasia Filtschew ◽  
Pablo Beato ◽  
Søren Birk Rasmussen ◽  
Christian Hess
Keyword(s):  
Gas Phase ◽  
Phase Analysis ◽  
Room Temperature ◽  
Storage Mechanism ◽  
In Situ Raman ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Ir Study

The role of platinum on the room temperature NOx storage mechanism and the NOx desorption behavior of ceria was investigated by combining online FT-IR gas-phase analysis with in situ Raman...

IN SITU SYNTHESIS, CHARACTERIZATION AND FREQUENCY DEPENDENT AC CONDUCTIVITY OF POLYANILINE/CoFe2O4 NANOCOMPOSITES

2011 ◽  
Vol 01 (03) ◽  
pp. 357-362 ◽  
Author(s):  
G. D. PRASANNA ◽  
H. S. JAYANNA
Keyword(s):  
Ac Conductivity ◽  
Room Temperature ◽  
In Situ Polymerization ◽  
In Situ Synthesis ◽  
Electron Micrograph ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Scanning Electron Micrograph ◽  
X Ray

The polyaniline (PANI)/ CoFe2O4 nanocomposites were prepared by an In Situ polymerization of aniline in an aqueous solution. The composites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrum,thermogravimetric analysis (TGA) and scanning electron micrograph (SEM). The AC conductivity and dielectric properties of these composites were investigated in the frequency range 1 kHz–10 MHz at room temperature. The AC conductivity was found to be constant up to 1 MHz and thereafter it increases steeply and it was observed maximum for the PANI with 60 wt% of CoFe2O4 nanocomposite. At lower frequencies the values of dielectric constant is maximum for pure CoFe2O4 nanoparticles.

scholarly journals Selective Nitration of Chlorobenzene by NO2 in the Alkali Zeolite NaZSM-5

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Scott J. Kirkby
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Temperature Dependent ◽  
Reaction Conditions ◽  
Cation Site ◽  
Zeolite Lattice ◽  
Reaction Proceeds ◽  
Ft Ir ◽  
Electron Donation

Chlorobenzene was reacted with NO2, in the initially acid-free zeolite NaZSM-5, to yield para-chloronitrobenzene exclusively. The precursors were loaded sequentially into self-supporting pellets of the zeolite, contained within a stainless steel cell, from the gas phase. The reaction proceeds spontaneously at room temperature. It is, however, very temperature dependent and effectively ceases at zero degrees Celsius. The reaction was monitored in situ using FT-IR. The active nitrating agent is formed from the partial electron donation by the NO2 to the Na+ cations present in the zeolite lattice. Under the reaction conditions, chlorobenzene is not readily mobile through the pore system; thus, only the molecules adsorbed near a cation site react to form para-chloronitrobenzene.

In situ FT-IR spectroscopic studies of curing reaction of HTPB and TDI on solid surface

2016 ◽  
Vol 33 (5) ◽  
pp. 452 ◽  
Author(s):  
Cuihua Li ◽  
Tao Luo ◽  
Xiaoxue Zhang ◽  
Jianhong Liu ◽  
Aimin Pang ◽  
...  
Keyword(s):  
Solid Surface ◽  
Spectroscopic Studies ◽  
Curing Reaction ◽  
Ft Ir ◽  
Ir Spectroscopic

FT-IR Micro-Spectroscopic Studies of Several Charge-Transfer Organic Electrical Conductors

1987 ◽  
Vol 41 (8) ◽  
pp. 1377-1382 ◽  
Author(s):  
John R. Ferraro ◽  
Hau H. Wang ◽  
John Ryan ◽  
Jack M. Williams
Keyword(s):  
Hydrogen Bonding ◽  
Charge Transfer ◽  
Room Temperature ◽  
Spectroscopic Studies ◽  
Infrared Reflectance ◽  
Bending Vibration ◽  
Ft Ir ◽  
Electrical Conductors ◽  
Reflectance Measurements ◽  
Vibrational Feature

A series of infrared reflectance measurements using FT-IR Micro methods were conducted on bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or “ET”) and bis(propylenedithio)tetrathiafulvalene (BPDT or “PT”) salts of the type (ET)2 X, where X = I3, AuCl2−, AuBr2−, AuI2−, I2Br−, IBr2, ICl2, ReO4−, ClO4−, and [Formula: see text]; and (PT)2 X, where X = I3−, IBr2−, I2Br−, and ICl2−. The technique is useful for characterizing, at room temperature, differences between β-, β′- and α′-type structures vs. α-structures. The β-, β′-, and α′-type structures show a vibrational feature at ∼1280 cm−1 which has been assigned as the -C-C-H bending vibration and is absent in the spectrum of the α-type salts. This vibration shifts toward higher frequency in going from the PT to the ET salts, and the results indicate stronger hydrogen bonding and harder lattices in the ET salts as opposed to the PT salts. This frequency shift also appears to be a function of the electronegativity of the halogen in the anion moiety of the charge-transfer salt.

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