Detours for Reaching at New Germylenes, Silylenes, Carbenes, and Carbenogermylenes through Substituted Cyclopropenylidenes at Ab initio and DFT Levels

Heavier atom containing X ₂SiC₂, and X ₂GeC₂ cyclopropenylidenes transform into new silylenes, germylenes, and carbenogermylenes at DFT and ab initio levels (X = H, CN, NH₂, and OMe). The number of transformations or rearrangements appear roughly proportional to the covalent radii of the group 14 elements (Ge > Si > C).     

Enzyme Free Electrochemiluminescence Sensor of Histamine Based on Graphite-carbon Nitride Nanosheets

The determination of histamine as one of the most important seafood poisoning compounds is essential nowadays. This paper reports a simple novel ECL sensor with g−C₃N₄ nanosheets (NSs) as an effective signal probe for the measurement of histamine without using any enzymatic reactions or complicated modifications. The ECL response of the sensor was linearly proportional to the concentration of histamine ranging from 1.0×10⁻⁷ to 7.5×10⁻⁴ mol/L, with a detection limit of 4.30×10⁻⁸ mol/L (R²=0.98401). The relative standard deviation (RSD) in repeatability and reproducibility tests were calculated to be 4.7 % and 3.6 % respectively. The presented sensor was successfully applied to the determination of histamine in canned tuna fish samples where it gave recoveries that ranged from 99.72 % to 101.96 % indicating that the method presented here is sensitive with high precision and is expected to have significant potential applications in clinical and the freshness quality of seafood.     

Contact Angle Measurements Using Sessile Drop and Micro-CT Data from Six Sandstones

Transport in Porous Media - Numerous sessile drop and micro-computed tomography (micro-CT) studies have been conducted to quantify geologic carbon storage formation wettability by measuring static...     

Extension of the exp-6 model to the simulation of vapor-liquid equilibria of primary alcohols and their mixtures

Configurational-biased Gibbs ensemble Monte Carlo simulations were performed to obtain the phase behavior of the homologous series of primary alcohols from ethanol to 1-heptanol. Molecular interactions in these systems are modeled by a newly developed exp-6 potential in combination with a Coulombic intermolecular potential. Some of exp-6 potential parameters required to describe these alcohols were taken from the previous literature data reported for methanol and n-alkanes. The oxygen's potential parameters were optimized to fit the coexistence curve of these alcohols to the experimental data. Simulated values of saturated liquid and vapor densities, vapor pressures and critical constants of the alcohols are in good agreement with experimental data. The efficiency of the new model in the prediction of binary phase diagram of water/ethanol and n-hexane/1-propanol mixtures is also evaluated. The calculated mole fractions in the vapor and liquid phases of these binary mixtures also show satisfactory agreement with the experimental data.     

Dynamic Surface Tension and Adsorption Kinetics of Sodium Lignosulfonate Aqueous Solutions

In the article, the dynamic surface tension of sodium lignosulfonate (SL) aqueous solutions are investigated using an axisymmetric drop shape analysis-profile method. The data are analyzed by the Langmuir, Frumkin, modified Frumkin, and modified Flory-Huggins equations. The results indicate that the Langmuir model's results with two adjustable parameters are comparable to that of other models with three or four adjustable parameters. Based on the simplicity of simulation, the Langmuir adsorption equation is used to correlate the dynamic adsorption processing. The aggregation between SL molecules and the variation of adsorption configuration are proposed to interpret the results of dynamic surface tension.      

Chemoselective and scalable preparation of alkyl tosylates under solvent-free conditions

The improved method for the efficient tosylation of alcohols has been reported using two procedures (A and B). Procedure A: methanol, ethanol, benzyl alcohols, and valuable ethylene glycols can be converted into their corresponding alkyl tosylates in very fast, simple, and efficient grinding method using potassium carbonate as solid base. Other primary and secondary alcohols need to add potassium hydroxide to reaction mixture (procedure B). High selectivity of tosylation was observed for these two procedures. Scale up ability was found in this method even in 100 mmol of substrate. The present method is the example of solid-state tosylation using tosyl chloride, and is a green chemical process due to solvent-free conditions.     

Synthesis and reactions of 3‐amino‐2‐methyl‐3H‐[1,2,4]triazolo[5,1‐b]‐quinazolin‐9‐one and 2‐hydrazino‐3‐phenylamino‐3H‐quinazolin‐4‐one

The reaction of 3‐N‐(2‐mercapto‐4‐oxo‐4H‐quinazolin‐3‐yl)acetamide ( 1 ) with hydrazine hydrate yielded 3‐amino‐2‐methyl‐3H‐[1,2,4]triazolo[5,1‐b]quinazolin‐9‐one ( 2 ). The reaction of 2 with o‐chlorobenzaldehyde and 2‐hydroxy‐naphthaldehyde gave the corresponding 3‐arylidene amino derivatives 3 and 4 , respectively. Condensation of 2 with 1‐nitroso‐2‐naphthol afforded the corresponding 3‐(2‐hydroxy‐naphthalen‐1‐yl‐diazenyl)‐2‐methyl‐3H‐[1,2,4]triazolo[5,1‐b]quinazolin‐9‐one ( 5 ), which on subsequent reduction by SnCl₂ and HCl gave the hydrazino derivative 6. Reaction of 2 with phenyl isothiocyanate in refluxing ethanol yielded thiourea derivative 7. Ring closure of 7 subsequently cyclized on refluxing with phencyl bromide, oxalyl dichloride and chloroacetic acid afforded the corresponding thiazolidine derivatives 8, 9 and 10 , respectively. Reaction of 2‐mercapto‐3‐phenylamino‐3H‐quinazolin‐4‐one ( 11 ) with hydrazine hydrate afforded 2‐hydrazino‐3‐phenylamino‐3H‐quinazolin‐4‐one ( 12 ). The reactivity 12 towards carbon disulphide, acetyl acetone and ethyl acetoacetate gave 13, 14 and 15 , respectively. Condensation of 12 with isatin afforded 2‐[N‐(2‐oxo‐1,2‐dihydroindol‐3‐ylidene)hydrazino]‐3‐phenylamino‐3H‐quinazolin‐4‐one ( 16 ). 2‐(4‐Oxo‐3‐phenylamino‐3,4‐dihydroquinazolin‐2‐ylamino)isoindole‐1,3‐dione ( 17 ) was synthesized by the reaction of 12 with phthalic anhydride. All isolated products were confirmed by their ir, ¹H nmr, ¹³C nmr and mass spectra.     

Kinetic studies of the hydrolysis of furfurylidene benzoylhydrazone

Summary The hydrolysis of furfurylidene benzoylhydrazone,FBH, in hydrochloric acid medium has been found to follow specific acid catalysis, whereas the hydrolysis in universal buffer medium has been found to follow general acid-base catalysis. Mechanisms for the hydrolysis in different acidic media have been postulated. The observed rate constants, secondary rate constants, activation and thermodynamic parameters for the hydrolysis of furfurylidene benzoylhydrazone have been reported. The effect of change in percentage of ethanol in the ethanol-buffer mixture on the rate of hydrolysis has been discussed.

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Kinetische Untersuchungen zur Hydrolyse von Furfurylidenbenzoylhydrazon

Zusammenfassung Es wurde festgestellt, daß die Hydrolyse von Furfurylidenbenzoylhydrazon (FBH) in HCl-Medium einer speziellen Säurekatalyse gehorcht, wohingegen die Hydrolyse in universellen Puffer-Medien nach einer generellen Säure-Base Katalyse abläuft. Es werden Mechanismen für die verschiedenen sauren Medien postuliert. Die beobachteten Geschwindigkeitskonstanten, die sekundären Geschwindigkeitskonstanten, Aktivierungs- und sonstige thermodynamische Parameter für die Hydrolyse von Furfurylidenbenzoylhydrazon werden berichtet. Der Effekt wechselnder Ethanolkonzentration auf die Hydrolysengeschwindigkeitskonstante in Ethanol-Puffer-Mischungen wird diskutiert.