scholarly journals Chemical Oxidative Condensation of Benzidine in Non-Aqueous Medium: Synthesis and Investigation of Oligomers and Polymer with Benzidine Diimine Units

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 34
Author(s):  
Ranush Durgaryan ◽  
Narine Durgaryan
Keyword(s):  
Oxidative Polymerization ◽  
Matrix Decomposition ◽  
Oxidative Condensation ◽  
Aromatic Diamines ◽  
Acid Media ◽  
Molar Ratios ◽  
Potassium Peroxydisulfate ◽  
Type Change ◽  
First Time ◽  
Semiconductor Type

The oxidative condensation of benzidine has been carried out in acetic acid media using potassium peroxydisulfate as the oxidizing agent. Using different monomer–oxidant molar ratios, benzidine dimer, trimer, and polymer have been synthesized for the first time. It was established that the polybenzidine structure is composed from a sequence of benzidinediimine and diphenylene units with amino/amino end groups and thus proves the possibility of ammonia elimination during the oxidative polymerization of aromatic diamines. The method seems to be common for the synthesis of polymers with the sequence of aromatic diimine and arylene units. TGA analysis of the obtained trimer and polymer was investigated, and the high thermostability of both the polymer and trimer was revealed. According to the obtained data, both polymer and trimer matrix decomposition started at 300 °C, and at 600 °C, 75.94% and of 69.40% of the initial weight remained, correspondingly. Conductivities of the polymer and trimer show a semiconductor-type change from temperature and after doping show an increase in conductivity up to 10−4 Sm/cm.

scholarly journals Protection of Petroleum Pipeline Carbon Steel Alloys with New Modified Core-Shell Magnetite Nanogel against Corrosion in Acidic Medium

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Gamal A. El Mahdy ◽  
Ayman M. Atta ◽  
Amro K. F. Dyab ◽  
Hamad A. Al-Lohedan
Keyword(s):  
Carbon Steel ◽  
Sulfonic Acid ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Core Shell ◽  
Magnetite Nanoparticle ◽  
Potassium Peroxydisulfate ◽  
Redox Initiator ◽  
Initiator System ◽  
First Time

New method was used to prepare magnetite nanoparticle based on reduction of Fe(III) ions with potassium iodide to produce Fe3O4nanoparticle. The prepared magnetite was stabilized with cross-linked polymer based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS to prepare novel core-shell nanogel. In this respect, Fe3O4/poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) magnetic nanogels with controllable particle size produced via free aqueous polymerization at 65°C have been developed for the first time. The polymer was crosslinked in the presence of N,N-methylenebisacrylamide (MBA) as a crosslinker and potassium peroxydisulfate (KPS) as redox initiator system. The structure and morphology of the magnetic nanogel were characterized by Fourier transform infrared spectroscopy (FTIR) and transmission and scanning electron microscopy (TEM and SEM). The effectiveness of the synthesized compounds as corrosion inhibitors for carbon steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed enhancement in inhibition efficiencies with increasing the inhibitor concentrations. The results showed that the nanogel particles act as mixed inhibitors. EIS data revealed thatRctincreases with increasing inhibitor concentration.

The effect of plasticization on the properties of poly(urethaneureas) based on oligoether diols, 2,4-toluenediisocyanate, and aromatic diamines

2018 ◽  
Vol 51 (4) ◽  
pp. 337-358 ◽  
Author(s):  
Vasiliy Tereshatov ◽  
Marina Makarova ◽  
Valeriy Senichev ◽  
Zhanna Vnutskikh ◽  
Tamara Oshchepkova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Arctic Climate ◽  
The Arctic ◽  
Aromatic Diamines ◽  
Plasticization Effect ◽  
Soft Segments ◽  
Potential Applications ◽  
Partial Crystallization ◽  
First Time

Segmented poly(urethaneureas) (SPUUs) modified with low glass transition temperature chemically inert liquids are of interest due to their controllable properties and potential applications under various environmental conditions. Investigation into the influence of plasticizers on the properties of SPUUs based on oligotetramethyleneoxide diol (polytetramethyleneoxide), oligopropyleneoxide diol (polypropyleneoxide), 2,4-toluenediisocyanate, Ethacure-300, and methylene-bis- o-chloroaniline was conducted. Partial crystallization of polytetramethyleneoxide segments was identified during cooling of some SPUU samples plasticized by di-(2-ethylhexyl)sebacate (DEHS) and tributyl phosphate. Polypropyleneoxide segments did not crystallize under the same conditions. A low crystallization temperature for the amorphous component of the polymer matrix in SPUU (−100°C to 103°C) was attained at a molecular mass ( Mn) of soft segments equal to 2000 g mol−1 and a DEHS concentration equal to 40–45%. A relationship between the mechanical properties of plasticized SPUU, microphase segregation, and dilution of the polymer matrix was found. For the first time, the effect of dilution with plasticizer on the strength of elastomers was considered. The plasticization effect on the mechanical properties of SPUU was investigated in the temperature diapason from 50°C to −70°C. The results of these investigations can be used in various technologies including the design of SPUUs with high elastic properties at temperatures as low as −70°C, typical of extreme conditions of the Arctic climate.

Novel conductive core–shell particles of elastomeric nanoparticles coated with polypyrrole

RSC Advances ◽  
2015 ◽  
Vol 5 (120) ◽  
pp. 98904-98909 ◽  
Author(s):  
Jiangru Zhang ◽  
Guicun Qi ◽  
Xiang Wang ◽  
Binghai Li ◽  
Zhihai Song ◽  
...  
Keyword(s):  
Shell Structure ◽  
Oxidative Polymerization ◽  
Core Shell ◽  
Conductive Particle ◽  
Core Shell Structure ◽  
Shell Particles ◽  
First Time

For the first time, an ultrafine conductive particle with core–shell structure, acrylonitrile-butadiene elastomeric nanoparticle (NBR-ENP) coated with polypyrrole (PPy), was prepared by in situ oxidative polymerization.

Deep eutectic solvent systems for FeCl3-catalyzed oxidative polymerization of 3-octylthiophene

2017 ◽  
Vol 19 (4) ◽  
pp. 910-913 ◽  
Author(s):  
Tae-Joon Park ◽  
Sang Hyun Lee
Keyword(s):  
Oxidative Polymerization ◽  
Deep Eutectic Solvent ◽  
Deep Eutectic Solvents ◽  
Solvent Systems ◽  
First Time

FeCl3-catalyzed oxidative polymerization of 3-octylthiophene was achieved using deep eutectic solvents (DESs) for the first time.

scholarly journals Composition analysis of liquid particles in the Arctic stratosphere under synoptic conditions

2006 ◽  
Vol 6 (3) ◽  
pp. 689-696 ◽  
Author(s):  
C. Weisser ◽  
K. Mauersberger ◽  
J. Schreiner ◽  
N. Larsen ◽  
F. Cairo ◽  
...  
Keyword(s):  
Equilibrium Temperature ◽  
Solid Particles ◽  
The Arctic ◽  
Composition Analysis ◽  
Molar Ratios ◽  
Frost Point ◽  
Synoptic Conditions ◽  
Lee Waves ◽  
Stratospheric Clouds ◽  
First Time

Abstract. Synoptic scale polar stratospheric clouds (PSCs) that formed without the presence of mountain lee waves were observed in early December 2002 from Kiruna/Sweden using balloon-borne instruments. The physical, chemical, and optical properties of the particles were measured. Within the PSC solid particles existed whenever the temperature was below the equilibrium temperature for nitric acid trihydrate and liquid particles appeared when the temperature fell below an even lower threshold about 3 K above the frost point with solid particles still present. The correlation of liquid supercooled ternary solution aerosols with local temperatures is a pronounced feature observed during this flight; average molar ratios H2O/HNO3 were somewhat higher than predicted by models. In addition HCl has been measured for the first time in liquid aerosols. The chlorine isotope signature served as a unique tool to identify unambiguously HCl dissolved in STS particles. Within a narrow temperature range of about three degrees above the frost point, the measured average amount of HCl in liquid particles is below 1 weight%.

Rapid Reactions of Phthalocyanines with Tellurium Tetrachloride in Non-aqueous Solutions

1999 ◽  
Vol 03 (06) ◽  
pp. 537-543 ◽  
Author(s):  
YUTAKA KAGAYA ◽  
HIROAKI ISAGO
Keyword(s):  
Aqueous Solutions ◽  
Zinc Complex ◽  
Magnetic Circular Dichroism ◽  
Equilibrium Constants ◽  
Lewis Base ◽  
Molar Ratios ◽  
Spectral Changes ◽  
Acid Base Equilibrium ◽  
Tellurium Tetrachloride ◽  
First Time

Rapid reactions of tetra(tert-butyl)phthalocyanine, H 2( tbpc ), and its zinc complex, [ Zn ( tbpc )], with tellurium tetrachloride ( TeCl 4) in non-aqueous solutions have been investigated. Upon mixing respective solutions containing the reactants, drastic spectral changes occurred in chloroform and toluene even at room temperature. The electronic spectra of the products indicated that the reactions involved an acid-base equilibrium where the phthalocyanines and tellurium tetrachloride acted as a Lewis base and a Lewis acid respectively. By monitoring the spectral changes based on various initial molar ratios of the reactants, the compositions of the products for each system have been determined. [ Zn ( tbpc )] formed a 1:1 ( tbpc : TeCl 4) adduct in both chloroform and toluene, showing the same spectra close to those of the known monoprotonated phthalocyanines. On the other hand, H 2( tbpc ) formed a 1:1 adduct in chloroform but a 1:3 adduct in toluene even though both products showed essentially the same spectra close to those of the known diprotonated phthalocyanines. Equilibrium constants have been calculated for the four systems. Magnetic circular dichroism (MCD) spectra of conjugated acids of phthalocyanines have been studied for the first time.

Precipitation and surface polymerizations of aniline at different aniline:oxidizer molar ratios

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Lucia Helena Mascaro ◽  
Débora Gonçalves
Keyword(s):  
Oxidative Polymerization ◽  
Reaction Times ◽  
Ammonium Persulfate ◽  
Open Circuit ◽  
Polymerization Process ◽  
Pani Film ◽  
Electrode Surfaces ◽  
Molar Ratios ◽  
Pt Electrodes ◽  
Vis Spectroscopy

AbstractThe oxidative polymerization of aniline was monitored by means of open-circuit potential (OCP) measurements of Pt electrodes immersed in an aqueous acidic medium containing different aniline:oxidizer (ammonium persulfate) molar ratios. Thin polyaniline (PANI) films were formed on the Pt electrode surfaces during the OCP measurements, and they were studied by SEM and cyclic voltammetry in a monomer-free solution at different reaction times. A precipitate also obtained during the polymerization process was analyzed by UV-VIS spectroscopy in 1-methyl-2-pyrrolidinone. It is observed that aniline or short oligomeric species are necessary to initiate the growth of a PANI film, which takes place at the first few minutes of the reaction.

New 1-(2-pyridinyl)-2-(o-, m-, p-hydroxyphenyl) benzimidazoles as corrosion inhibitors for API 5L X52 steel in acid media

2018 ◽  
Vol 65 (2) ◽  
pp. 166-175 ◽  
Author(s):  
Edelmira Rodriguez-Clemente ◽  
Victoria Barrera-Pascual ◽  
Humberto Cervantes-Cuevas ◽  
Jorge Aldana-González ◽  
Jorge Uruchurtu-Chavarin ◽  
...  
Keyword(s):  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Petroleum Industry ◽  
Acid Media ◽  
Content Type ◽  
Impedance Spectroscopy Technique ◽  
X52 Steel ◽  
First Time ◽  
Practical Implications ◽  
Corrosion System

Purpose This paper aims to evaluate the corrosion inhibition capacities of synthesized compounds 1-(2-pyridinyl)-2-(o, m-, p-hydroxyphenyl) benzimidazoles in API 5L X52 steel/HCl 1M corrosion system. Design/methodology/approach Electrochemical impedance spectroscopy technique was used. Findings The studies determined that under stagnant conditions, the durability and efficiency were maintained over 80 per cent for up to 500 h of immersion, while the residence time started to decrease after 150 h at the best inhibitor concentration (150 ppm). Practical implications This work may help to attenuate corrosion problems in the petroleum industry. Originality/value It is the first time that 1-(2-pyridiniy)-2-(o-, m-, p-hydroxyphenyl) benzimidazoles were evaluated as corrosion inhibitors.

scholarly journals Human Plasma and Recombinant Hemopexins: Heme Binding Revisited

2020 ◽  
Author(s):  
Elena Karnaukhova ◽  
Catherine Owczarek ◽  
Peter Schmidt ◽  
Dominik J. Schaer ◽  
Paul W. Buehler
Keyword(s):  
Protein S ◽  
Soret Band ◽  
Cell System ◽  
Heme Binding ◽  
Systematic Analysis ◽  
Molar Ratios ◽  
Recombinant Production ◽  
Wide Range ◽  
Titration Data ◽  
First Time

Abstract: Plasma hemopexin (HPX) is the key antioxidant protein of the endogenous clearance pathway that limits the deleterious effects of heme released from hemoglobin and myoglobin. During intra-vascular hemolysis, heme partitioning to protein and lipid increases as the plasma concentration of HPX declines. Therefore, the development of HPX as a replacement therapy during high heme stress could be a relevant intervention for hemolytic disorders. A logical approach to enhance HPX yield involves recombinant production strategies from human cell lines. The present study focuses on a biophysical assessment of heme binding to recombinant human HPX (rhHPX) produced in the Expi293FTM (HEK293) cell system. In this report, we examine rhHPX in comparison with plasma HPX using a systematic analysis of protein structural and functional characteristics related to heme binding. Analysis of rhHPX by UV/Vis absorption spectroscopy, circular dichroism (CD), SEC-HPLC and catalase-like activity demonstrated a similarity to HPX fractionated from plasma. In particular, the titration of HPX apo-protein(s) with heme was performed for the first time using a wide range of heme concentrations to model HPX-heme interactions to approximate physiological conditions (from extremely low to more than 2-fold heme excess). The CD titration data showed an induced bisignate CD Soret band pattern typical for plasma and rhHPX versions at low heme-to-protein molar ratios and demonstrated that further titration is dependent on the amount of protein-bound heme to the extent that the arising opposite CD couplet results in a complete inversion of the observed CD pattern. The data generated in this study suggests more than one binding site in both plasma and rhHPX. Further, our study provides a useful analytical platform for detailed characterization of HPX-heme interactions and potentially, novel HPX fusion constructs.

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