scholarly journals Physico-chemical studies of some aminobenzoic acid hydrazide complexes

2004 ◽  
Vol 69 (4) ◽  
pp. 255-264 ◽  
Author(s):  
Abd El ◽  
Abd El ◽  
Gamel El ◽  
Abd El
Keyword(s):  
Acid Hydrazide ◽  
Conductometric Titration ◽  
Aminobenzoic Acid ◽  
X Ray ◽  
Physico Chemical ◽  
Coordination Process ◽  
Different Temperatures ◽  
Chemical Studies ◽  
The Stability ◽  
Thermal Stability Of

The stability constants and related thermodynamic functions characterizing the formation of divalent Ni, Cu, Zn, Cd and Hg complexes with o- and p-aminobenzoic acid hydrazide were determined potentiometrically at different temperatures. The formations of the complexes are endothermic processes. The formed bonds are mainly electrostatic. Conductometric titration was carried out to determine the stoichiometry and stability of the formed complexes. The structures of complexes were characterized by their IR, 1H-NMR and 13C-NMR spectra, as well as X-ray diffractograms. The coordination process takes place through the carbonyl group and the terminal hydrazinic amino group. The thermal stability of the complexes was followed in the temperature range 20?600 ?C.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

Physico-chemical Characteristics and Oxidative Stability of Date-Pits Oil during Storage at Different Temperatures

2016 ◽  
Vol 12 (4) ◽  
pp. 385-393
Author(s):  
Naima Al-Kharousi ◽  
Mohammed Al-Khusaibi ◽  
Ismail Al-Bulushi ◽  
Nejib Guizani ◽  
Mostafa Waly ◽  
...  
Keyword(s):  
Oxidative Stability ◽  
Value Added ◽  
Stability Index ◽  
Acid Value ◽  
Food Ingredients ◽  
C Storage ◽  
Physico Chemical ◽  
Different Temperatures ◽  
The Stability ◽  
Date Pits

Abstract In this study, oxidative stability of date-pits (i. e. Khalas variety) was investigated during storage as a function of temperature. The stability of date-pits oil was determined by measuring acid value (AV), peroxide value (PV), p-anisidine value (PAV), tocopherol and oxidative stability index. Initial characteristics of oil were assessed by measuring its physico-chemical and melting characteristics, fatty acids composition and aflatoxin. Storage of date-pits caused highest reduction in linoleic acid (C18:2, ω6) followed by oleic acid (C18:1, ω9). AV, PV and PAV of the fresh oil were 1.41 mg KOH/g oil, 3.30 meq/kg oil and 0.60, respectively. These values increased linearly at slower rate in the case of 30 °C storage, while sharp rise was observed after 40 days in cases of 100 and 150 °C storage (p < 0.05). The results of this study indicate that date pits oil had a good oxidative and thermal stability and could thus be used to develop value-added food ingredients.

A new high-temperature inorganic–organic proton conductor: lanthanum sulfophenyl phosphate

2016 ◽  
Vol 70 (3) ◽  
Author(s):  
Ming-Feng Song ◽  
Zhong-Fang Li ◽  
Guo-Hong Liu ◽  
Su-Wen Wang ◽  
Xiao-Yan Yin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Layered Structure ◽  
Proton Conductor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Different Temperatures ◽  
Thermal Stability Of

AbstractLanthanum sulfophenyl phosphate (LaSPP) was synthesized by m-sulfophenyl phosphonic acid and lanthanum nitrate. UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy indicate that the desired product was obtained and its elementary composition and typical layered structure were determined by energy dispersive X-ray spectroscopy and scanning electron microscopy. Transmission electron microscopy (TEM) proved its typical layered structure and X-ray diffraction spectroscopy indicated its good crystallinity and the interlayer distance of about 15.67 Å , which matches the value obtained by TEM (2.0 nm). Thermogravimetry and differential thermal analysis revealed good thermal stability of LaSPP. Proton conductivity of LaSPP was measured at different temperatures and relative humidities (RH), reaching values of 0.123 S cm

scholarly journals High-strength fluoroanhydrite composition

2019 ◽  
Author(s):  
Grigory Yakovlev ◽  
Jadvyga Keriene ◽  
Valery Grakhov ◽  
Rostislav Drochytka ◽  
Anastasiya Gordina ◽  
...  
Keyword(s):  
Water Resistance ◽  
Raw Materials ◽  
Waste Product ◽  
High Strength ◽  
Structure And Properties ◽  
X Ray ◽  
Physico Chemical ◽  
Gypsum Plaster ◽  
Chemical Studies ◽  
Increased Strength

The research studies the properties of a high-strength anhydrite composition based on fluoroanhydrite, a waste product of hydrofluoric acid. To activate fluoranhydrite, Na3PO4 sodium phosphate was added to the composition in an amount of 3% of the mass. The physico-chemical studies of the structure and properties of activated fluoroanhydrite conducted using infrared spectroscopy and X-ray phase analysis showed changes in the composition of the hardened composite, and the study of the fluoroanhydrite microstructure revealed the formation of a denser matrix with the increased strength. An increase in the water resistance of the developed binder matrix was noted. The composition can be used as a cheap substitute for gypsum plaster due to the low prime cost of raw materials, and also contribute to the improvement of the environmental situation in fluoroanhydrite disposal sites.

scholarly journals Structures and thermal stability of the α-LiNH4SO4 polytypes doped with Er3+ and Yb3+

2017 ◽  
Vol 73 (1) ◽  
pp. 122-133 ◽  
Author(s):  
N. P. Sabalisck ◽  
C. Guzmán-Afonso ◽  
C. González-Silgo ◽  
M. E. Torres ◽  
J. Pasán ◽  
...  
Keyword(s):  
Single Crystals ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Wide Range ◽  
Cyclic Temperature ◽  
Polymorphic Forms ◽  
The Stability ◽  
Thermal Stability Of

In order to clarify the polymorphism in the lithium sulfate family, LiRE x (NH4)1 − x SO4 (0.5 ≤ x ≤ 4.0 mol%, nominal value; RE = Er3+, Yb3+ and Dy3+) crystals were grown from aqueous solution by slow evaporation between 298 and 313 K. The doping of the samples allowed us to obtain two polymorphic forms, α and β, of LiNH4SO4 (LAS). By means of X-ray diffraction (XRD) in single crystals, we determined the crystal structures of two new α-polytypes, which we have named α1- and α2-LAS. They present the same space group P21/c and the following relation among their lattice parameters: a 2 = −c 1, b 2 = −b 1, c 2 = −2a 1 − c 1. In order to evaluate the stability of the new α-polytypes, we performed thermal analysis, X-ray diffraction and dielectric spectroscopy on single crystals and polycrystalline samples over the cyclic temperature range: 190 → 575  → 190 K. The results obtained by all the techniques used in this study demonstrate that α-polytypes are stable across a wide range of temperatures and they show an irreversible phase transition to the paraelectric β-phase above 500 K. In addition, a comparative study of α- and β-polytypes shows that both polymorphic structures have a common axis, with a possible intergrowth that facilitates their coexistence and promotes the reconstructive α → β transition. This intergrowth was related to small anomalies detected between 240 and 260 K, in crystals with an α-habit.

Study of the Hydration Process of Synthetic Preparation of Ettringite by Direct Addition of Aluminum Sulfate and Calcium Hydroxide

2018 ◽  
Vol 276 ◽  
pp. 60-65
Author(s):  
Marcela Fridrichová ◽  
Dominik Gazdič ◽  
Jana Mokrá ◽  
Karel Dvořák
Keyword(s):  
Calcium Hydroxide ◽  
Aluminum Sulfate ◽  
Xrd Analysis ◽  
Standard Laboratory ◽  
X Ray Diffraction ◽  
X Ray ◽  
Saturated Water ◽  
Direct Addition ◽  
Different Temperatures ◽  
The Stability

The stability of ettringite as high-watery mineral is highly dependent on the ambient temperature. Under standard laboratory conditions, onset of decomposition of this phase occurs at temperature of 80°C already and the theoretical temperature of the complete decomposition of ettringite is 180°C. Ettringite decomposition can occur at significantly different temperatures under humidity conditions other than the laboratory ones. Within the work verification of the possibility of synthetic preparation of ettringite by direct addition of aluminum sulfate, Al2(SO4)3·18H2O, and calcium hydroxide, Ca (OH)2, as an alternative method to the yeelimite hydration procedure was carried out. The stability of the resulting systems was examined in two different environments, namely in a laboratory environment and the environment of saturated water vapour. The phase composition of the samples was determined by X-ray diffraction (XRD) analysis, thermal analysis and scanning electron microscopy (SEM).

Liquid Crystalline Behavior of Mixture of Two Non-Mesogenic Compounds

2010 ◽  
Vol 428-429 ◽  
pp. 292-296
Author(s):  
J. Mahadeva ◽  
Nagappa
Keyword(s):  
Liquid Crystalline ◽  
Interfacial Area ◽  
Ammonium Bromide ◽  
Polar Group ◽  
X Ray Diffraction ◽  
Optical Studies ◽  
X Ray ◽  
Molecular Length ◽  
Different Temperatures ◽  
The Stability

The lyotropic liquid crystalline behavior of N-Cetyl-N, N, N, Trimethyl Ammonium Bromide (CTAB) with ethylene glycol (EG) has been investigated. These compounds are non-mesogenic in nature and exhibits Sm A, Sm B and Sm G phases. The stability of the phases is investigated using X-ray diffraction and optical studies. The layer thickness and molecular length are calculated using Bragg’s equation. The interfacial area per polar group and average thickness of hydrocarbon layers are estimated for different concentrations of the mixtures at different temperatures.

Stability of Ceftazidime and Heparin in Four Different Types of Peritoneal Dialysis Solutions

2018 ◽  
Vol 38 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Surendra Kandel ◽  
Syed Tabish R. Zaidi ◽  
S. Troy Wanandy ◽  
Long C. Ming ◽  
Ronald L. Castelino ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
High Performance ◽  
Anticoagulant Activity ◽  
Storage Conditions ◽  
Color Changes ◽  
Physico Chemical ◽  
Different Temperatures ◽  
The Stability ◽  
Dialysis Solutions ◽  
Potential Use

Background Intraperitoneal (IP) administration of ceftazidime is recommended for the treatment of peritoneal dialysis-associated peritonitis (PDAP) from Pseudomonas. Patients with PDAP may also need IP heparin to overcome problems with drainage of turbid peritoneal dialysis (PD) fluids and blockage of catheters with fibrin. Physico-chemical stability of ceftazidime and heparin, and biological stability of heparin in many types of PD solutions is unknown. Therefore, we investigated the stability of ceftazidime and heparin in 4 types of PD solutions. Methods A total of 12 PD bags (3 for each type of solution) containing ceftazidime and heparin were prepared and stored at 4°C for 120 hours, and then at 25°C for 6 hours, and finally at 37°C for 12 hours. An aliquot was withdrawn after predefined time points and analyzed for the concentration of ceftazidime and heparin using high-performance liquid-chromatography (HPLC). Samples were assessed for pH, color changes, particle content, and anticoagulant activity of heparin. Results Ceftazidime and heparin retained more than 91% of their initial concentration when stored at 4°C for 120 hours followed by storage at 25°C for 6 hours and then at 37°C for 12 hours. Heparin retained more than 95% of its initial activity throughout the study period. Particle formation was not detected at any time under the storage conditions. The pH and color remained essentially unchanged throughout the study. Conclusions Ceftazidime-heparin admixture retains its stability over long periods of storage at different temperatures, allowing its potential use for PDAP treatment in outpatient and remote settings.

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