scholarly journals A STUDY OF CORROSION INHIBITON EFFECT OF THIOSEMICARBAZIDE BASED SCHIFF BASE ON ALUMINIUM METAL IN ACIDIC MEDIUM

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
V.K. Swami ◽  
V.K. Swami ◽  
V.K. Swami
Keyword(s):  
Schiff Base ◽  
Acidic Medium ◽  
Inhibition Efficiency ◽  
Significant Loss ◽  
Stable Form ◽  
Sem Study ◽  
Ft Ir ◽  
And Control ◽  
Aluminium Metal ◽  
Percentage Inhibition Efficiency

Corrosion is the destruction of metal surface by the reaction with its environment (humidity, gases, acid, alkaline etc.). In this process metal convert in to the more stable form such as sulphide oxide etc. Corrosion of materials and structures is a hindrance to the development of society as it causes significant loss to the economy, leads to pollution, and leads to serious disasters, hence its prevention and control is of great benefit for the humanity. Addition of corrosion inhibitors is one of the practical and easy methods to protect metals and alloys against attack of corrosion in many industrial environments. In this chapter thiosemicarbazide based Schiff base 2-[(3,4-dihydroxy-5-nitrophenyl)methylidene]hydrazine1-carbothioamide (DHNPMHC) was synthesized and characterized using elemental analysis, FT-IR and UV–Vis methods. The inhibition efficiency of Schiff base DHNPMHC against aluminium corrosion in 0.5 M HCl was examined using mass loss measurement and scanning electron microscopy (SEM). Results showed that DHNPMHC is an effective inhibitor for aluminium corrosion in 0.5 M HCl solution. The inhibition efficiency also increased with concentration of inhibitor increased. Maximum percentage inhibition efficiency 92.6 % (at 4-hour immersion time) is shown at highest concentration of inhibitor 5% (5X10-5M). Adsorption of the inhibitor on the aluminium surface followed Langmuir adsorption isotherm. SEM study of aluminium surface in presence of inhibitor and in absence of inhibitor also supports the inhibition of corrosion in acidic medium. All results show that the Schiff base of thiosemicarbazide (DHNPMHC) is excellent corrosion inhibitor for aluminium in 0.5 M HCl.

A Collaborative Study to Establish an International Standard for Alpha-Thrombin

1992 ◽  
Vol 67 (04) ◽  
pp. 424-427 ◽  
Author(s):  
P J Gaffney ◽  
A B Heath ◽  
J W Fenton II
Keyword(s):  
Elevated Temperatures ◽  
Collaborative Study ◽  
World Health Organisation ◽  
Significant Loss ◽  
Thrombin Inhibitors ◽  
World Health ◽  
Expert Committee ◽  
International Standard ◽  
Assay Procedure ◽  
And Control

SummarySince 1975 an International Standard for Thrombin of low purity has been used. While this standard was stable and of value for calibrating thrombins of unknown potency the need for a pure a-thrombin standard arose both for accurate calibration and for precise measurement of thrombin inhibitors, notably hirudin. An international collaborative study was undertaken to establish the potency and stability of an ampouled pure a-thrombin preparation. A potency of 97.5 international units (95% confidence limits 86.5-98.5) was established for the new a-thrombin standard (89/ 588) using a clotting-assay procedure. Stability data at various elevated temperatures indicated that the standard could be transported and stored with no significant loss of potency.Ampoules of lyophilised a-thrombin (coded 89/588) have been recommended as an International Standard for a-thrombin with an assigned potency of 100 international units per ampoule by the International Society for Thrombosis and Haemostasis (Thrombin and its Inhibitors Sub-Committee) in Barcelona, Spain in July 1990 while the Expert Committee on Biological Standardisation and Control of the World Health Organisation will consider its status at its next meeting in Geneva in 1991.

Chiral Mn(III) Salen Complex Immobilized on CuFe2O4@SiO2-NH2 NPs: A Cheap and Efficient Catalyst for N-arylation of Aryl Halides and Phenylboronic Acid Under Mild Conditions

2020 ◽  
Vol 17 (11) ◽  
pp. 857-863
Author(s):  
Mohammad Ali Nasseri ◽  
Seyyedeh Ameneh Alavi ◽  
Milad Kazemnejadi ◽  
Ali Allahresani
Keyword(s):  
Phenylboronic Acid ◽  
Significant Loss ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Efficient Catalyst ◽  
Aryl Chlorides ◽  
Mild Conditions ◽  
Cross Coupling Reactions ◽  
Salen Complex ◽  
Ft Ir

A convenient and efficient chiral CuFe2O4@SiO2-Mn(III) Ch.salen nanocatalyst has been developed for the C-N cross-coupling reactions of aryl halides/ phenylboronic acid with N-heterocyclic compounds in water and/or DMSO under mild conditions. The catalyst could be applied for the N-arylation of a variety of nitrogen-containing heterocycles with aryl chlorides, bromides, iodides and phenylboronic acid under mild conditions. Moderate to good yields were achieved for all substrates. The structure of catalyst was characterized using various techniques including FT-IR, FE-SEM, EDX, XRD, TEM and TGA. The catalyst can be simply recovered and reused for several times without significant loss of activity.

Synthesis of Chalcone Derivatives by Phthalhydrazide-Functionalized TiO2-Coated Nano-Fe3O4 as a New Heterogeneous Catalyst

2020 ◽  
Vol 17 ◽  
Author(s):  
Forough Motamedi Nia ◽  
Mahnaz Farahi ◽  
Bahador Karami ◽  
Raziyeh Keshavarz
Keyword(s):  
Heterogeneous Catalyst ◽  
Significant Loss ◽  
Magnetic Nanocatalyst ◽  
Chalcone Derivatives ◽  
Ft Ir ◽  
Nano Fe3o4

Abstract:: Phthalhydrazide immobilized on TiO2-coated nano Fe3O4 (Fe3O4-P) was synthesized and characterized by FT-IR, XRD, SEM, EDS and VSM analysis. The resulting magnetic nanocatalyst was used as a catalyst for the synthesis of chalcone derivatives which affords the desired products in good to excellent yields. This catalyst can be isolated readily after completion of the reaction by an external magnetite field and reused several times without significant loss of activity.

scholarly journals Clean one-pot multicomponent synthesis of pyrans using a green and magnetically recyclable heterogeneous nanocatalyst

SynOpen ◽  
2021 ◽  
Author(s):  
Mina Ghassemi ◽  
Ali Maleki
Keyword(s):  
Room Temperature ◽  
Significant Loss ◽  
Copper Ferrite ◽  
Multicomponent Synthesis ◽  
Thermo Gravimetric ◽  
Sem Images ◽  
One Pot ◽  
Three Component Reaction ◽  
Ft Ir ◽  
The One

Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition method and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde and a β-ketoester in ethanol at room temperature. Then it was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) analysis, scanning electron microscopy (SEM) images, thermo gravimetric and differential thermo gravimetric (TGA/DTG) analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, no use of eternal energy source and using a green solvent provide benign, mild, and environmentally friendly reaction conditions; as well, ease of catalyst recovering, catalyst recyclability, no use of column chromatography and good to excellent yields are extra advantages of this work.

scholarly journals Synthesis and Structural Characterization of (E)-4-[(2-Hydroxy-3-methoxybenzylidene)amino]butanoic Acid and Its Novel Cu(II) Complex

Molbank ◽  
10.3390/m1179 ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. M1179
Author(s):  
Eleftherios Halevas ◽  
Antonios Hatzidimitriou ◽  
Barbara Mavroidi ◽  
Marina Sagnou ◽  
Maria Pelecanou ◽  
...  
Keyword(s):  
Schiff Base ◽  
Gamma Aminobutyric Acid ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Polymeric Compound ◽  
Bridging Ligands ◽  
1H And 13C Nmr ◽  
One Dimensional ◽  
Ft Ir

A novel Cu(II) complex based on the Schiff base obtained by the condensation of ortho-vanillin with gamma-aminobutyric acid was synthesized. The compounds are physico-chemically characterized by elemental analysis, HR-ESI-MS, FT-IR, and UV-Vis. The complex and the Schiff base ligand are further structurally identified by single crystal X-ray diffraction and 1H and 13C-NMR, respectively. The results suggest that the Schiff base are synthesized in excellent yield under mild reaction conditions in the presence of glacial acetic acid and the crystal structure of its Cu(II) complex reflects an one-dimensional polymeric compound. The molecular structure of the complex consists of a Cu(II) ion bound to two singly deprotonated Schiff base bridging ligands that form a CuN2O4 chelation environment, and a coordination sphere with a disordered octahedral geometry.

Palladium nanoparticles immobilized on a magnetic chitosan-anchored Schiff base: applications in Suzuki–Miyaura and Heck–Mizoroki coupling reactions

2017 ◽  
Vol 41 (13) ◽  
pp. 5595-5604 ◽  
Author(s):  
Anuradha Anuradha ◽  
Shweta Kumari ◽  
Samaresh Layek ◽  
Devendra D. Pathak
Keyword(s):  
Schiff Base ◽  
Palladium Nanoparticles ◽  
Coupling Reactions ◽  
Magnetic Chitosan ◽  
Ft Ir

A palladium nanocatalyst Fe3O4@CS-SB-Pd has been synthesized and characterized by FT-IR, XRD, XPS, FESEM, EDX, TEM, TGA, and ICP-AES analysis.

Synthesis,Characterization and Evaluation of Biological Activity of Sulfonylhydrazide-Schiff Base" (E)- N’-(2,5-dimethoxybenzalidene) naphthalene-2-sulfonohydrazide"

2020 ◽  
Vol 8 (1) ◽  
pp. 01-11
Author(s):  
Sameer Amereih ◽  
Abd Daraghmeh ◽  
Ismail Warad ◽  
Mohammed Al-Nuri
Keyword(s):  
Schiff Base ◽  
Inhibitory Concentration ◽  
Condensation Reaction ◽  
Gram Negative Bacteria ◽  
Biological Applications ◽  
Bacteriostatic Effect ◽  
1H And 13C Nmr ◽  
13C Nmr Analysis ◽  
Ft Ir

Condensation reaction of naphthalene -2-Sulfonylhydrazide, as starting material with 2,5-dimethoxy benzaldehyde was used to produce (E)-N’-(2,5-dimethoxybenzalidene)naphthalene-2-sulfonohydrazide. The Schiff base product was isolated, purified and then spectrally characterized via UV-Vis, GC/MS, FT-IR, 1H and 13C NMR analysis, where strong evidences confirmed the formation of the desired product. Antimicrobial activity of Schiff base product was evaluated in vitro against several types of bacteria such as: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and MRSA by Minimum Inhibitory Concentration (MIC) test using tetracycline (TE) as a standard antibiotic. The tests showed a promising bacteriostatic effect of this compound against gram negative bacteria such as P. aeruginosa and K. pneumoniae, such character is valuable for biological applications.

scholarly journals Occurrence of polymorphism in famotidine raw materials

2014 ◽  
Vol 70 (a1) ◽  
pp. C1563-C1563
Author(s):  
Marilene Ângelo ◽  
Jennifer Jacon ◽  
Olimpia Maria Santos ◽  
Edith Cristina Cazedey ◽  
Rudy Bonfilio ◽  
...  
Keyword(s):  
Raw Materials ◽  
Polymorphic Form ◽  
Raw Material ◽  
Stable Form ◽  
Reference Standard ◽  
H2 Receptor Antagonist ◽  
Scanning Calorimetry ◽  
Histamine H2 Receptor ◽  
Ulcer Disease ◽  
And Control

Polymorphs are compounds with the same chemical composition, however the molecules are arranged in at least two different ways in the solid state. Famotidine is a histamine H2-receptor antagonist inhibitor of gastric secretion and widely used in gastric and duodenal ulcer disease. Two polymorphs are described for famotidine, A and B. The polymorph A is the most thermodynamically stable form and polymorph B is the kinetically favored form being marketed because it presents greater pharmacological activity. The aim of this study was to evaluate the occurrence of famotidine polymorphs in five raw materials acquired from different suppliers. The reference standard (USP) was also analyzed. All samples were characterized by powder X-ray diffraction (PXRD), infrared spectrophotometry (IR-ATR) and differential scanning calorimetry (DSC). PXRD analysis enables us to identify form B in five raw material samples and in the reference standard (USP). However, one of the raw materials additionally shows the presence of polymorphic form A. The DSC and IR-ATR techniques were essential to identify the polymorphic forms of famotidine confirming the results obtained by PXRD. Since the presence of polymorphs can compromise the effectiveness and safety of medicines and there is no official methodology of analysis and control of polymorphism in famotidine raw materials, the polymorphic contamination found in this study are being further analyzed and their physicochemical properties are being evaluated.

scholarly journals Electrochemical and Surface Morphological Studies of Carbon Steel Corrosion by a Novel Polynuclear Schiff Base in HCl Solution

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
K. S. Shaju ◽  
K. Joby Thomas ◽  
Vinod P. Raphael ◽  
Aby Paul
Keyword(s):  
Weight Loss ◽  
Schiff Base ◽  
Carbon Steel ◽  
Hydrochloric Acid ◽  
Adsorption Isotherm ◽  
Acid Solution ◽  
Corrosion Inhibition ◽  
Hydrochloric Acid Solution ◽  
Inhibition Efficiency ◽  
Morphological Studies

The corrosion inhibition efficiency of a potential polynuclear Schiff base, (s)-2-(anthracene-9 (10H)-ylidene amino)-5-guanidinopentanoic acid (A9Y5GPA), on carbon steel (CS) in 1 M hydrochloric acid solution has been investigated using weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization studies. The corrosion inhibition efficiencies of parent amine [(s)-2-amino-5-guanidinopentanoic acid] and parent ketone (anthracene-9 (10H)-one) on carbon steel in 1.0 M hydrochloric acid solution have also been investigated using weight loss studies. The electrochemical and weight loss data established that the inhibition efficiency on CS increases with the increase in the concentration of inhibitor, A9Y5GPA. The adsorption of A9Y5GPA obeys the Langmuir adsorption isotherm. Thermodynamic parameters (Kads, ΔGads0) were calculated using the adsorption isotherm. Activation parameters of the corrosion process (Ea, ΔH* and ΔS*) were also calculated from the corrosion rates obtained from temperature studies. Tafel plot analysis revealed that A9Y5GPA acts as a mixed-type inhibitor. A probable inhibition mechanism was also proposed. Surface morphology of the carbon steel specimens in the presence and absence of the inhibitor was evaluated by SEM analysis.

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