Water-Based Oil Spill Dispersants Based on Rosin Formaldehyde Resins

Water-soluble surfactants based on rosin acids were synthesized from condensed rosin acid-formaldehyde. This was completed by esterification of series of rosin acid formaldehyde resins with poly(ethylene glycol) having different molecular weights to produce series of rosin esters. The structure of the produced resins was determined by infrared and ¹HNMR analysis. The molecular weight of the produced surfactants was determined by gel permeation chromatography (GPC) technique. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The surface tension, critical micelle concentration (CMC), and surface activities were determined at different temperatures. Surface parameters such as surface excess concentration (Γmax), the area per molecule at interface (A_min), and the effectiveness of surface tension reduction (πCMC) were determined from the adsorption isotherms of the prepared surfactants. Some thermodynamic data for the adsorption process were calculated and are discussed. The dispersion efficiency of the prepared surfactants as petroleum oil spill dispersants was determined and correlated with the surface activity, concentrations of the prepared surfactants and type of petroleum crude oil.     

Effects of inorganic ions on the binding of triflupromazine and chlorpromazine to bovine serum albumin studied by spectrometric methods

The effects of inorganic salts, NaCl, NaBr, NaI, Na2SO4, KCl, KBr, KI, on the binding constants (Ks) of psychotropic phenothiazine drugs, triflupromazine (TFZ) and chlorpromazine, to bovine serum albumin (BSA) were examined by using second-derivative spectrophotometry. All of the salts examined, with the exception of Na2SO4, decreased the K values significantly, depending on the concentration of the salt, e.g., the decrease in the K values of both drugs were about 40% for 0.1 M NaCl. The results obtained with Na2SO4 indicated that neither Na+ nor SO4(2-) had any affect on the binding of the phenothiazines to BSA. Based on the Na2SO4 results and the finding that the effect of each potassium salt on binding was quite similar to that of the corresponding sodium salt, the effects of these halogen salts can be considered to be derived from their anions, although the phenothiazines are positively charged at pH 7.4. The effectiveness of the anions was determined to occur in the following order: I->Br->Cl-; these results coincided with the published order of the binding affinity of these anions to albumin. The 19F-NMR spectra of TFZ in the presence of each of these halogen salts revealed a concentration-dependent decrease in the intensity of the signal at 13.8 ppm that had previously been assigned to the TFZ bound to Site II. Consequently, the effects of these anions on the binding of positively charged phenothiazine drugs are thought to be local steric effects caused by the binding of these anions to Site II.     

The single vehicle pickup and delivery problem with time windows: intelligent operators for heuristic and metaheuristic algorithms

The single vehicle pickup and delivery problem with time windows is an important practical problem, yet only a few researchers have tackled it. In this research, we compare three different approaches to the problem: a genetic algorithm, a simulated annealing approach, and a hill climbing algorithm. In all cases, we adopt a solution representation that depends on a duplicate code for both the pickup request and its delivery. We also present an intelligent neighborhood move, that is guided by the time window, aiming to overcome the difficult problem constraints efficiently. Results presented herein improve upon those that have been previously published.     

Numerical Analysis of Coupled Heat and Mass Transfer Phenomena in Concrete at Elevated Temperatures

In this work, we present a novel methodology for incorporating the effect of fibre surface morphology on liquid water transport in polymer electrolyte membrane fuel cell gas diffusion layers (GDLs). Roughness features presented on the surface of the fibre are analysed using atomic force microscopy and are found to significantly impact the capillary pressure of liquid water pathways propagating through the GDL. A threshold capillary pressure was defined as the largest capillary pressure exhibited by the liquid water phase during the invasion of the throat. The threshold capillary pressures observed in the presence of roughness features are significantly greater than those in the absence of roughness features. Two-dimensional circumferential roughness models in cylindrical and converging-diverging throats are established, and an interfacial meniscus advancing algorithm is presented to determine the resulting threshold capillary pressures required for liquid water penetration. Revised Young–Laplace equations, which are particularly useful for pore network modeling, are suggested for calculating threshold capillary pressures that account for the effect of the roughness of throats with intrinsic contact angles greater than \(90^{\circ }\).     

Ligand effects on metal-oxygen stretching frequencies in dioxomolybdenum(VI) complexes

Summary Several new seven-coordinated dioxomolybdenum(VI) heterochelates, [MoO₂(AA)(BBB)], where AA = bidentate ligand = ethylenediamine, 2-aminoethylpyridine,o-pheny-lenediamine,o-phenanthroline or 2,2-dipyridyl; BBB = tridentate ligand (the Schiff base derived from benzoylhydrazide and salicylaldehyde), have been synthesized and characterized by elemental analysis, molar conductance, molecular weight, i.r. spectra and magnetic susceptibility measurements. The principle of coordination number expansion of a six coordinate homochelate, [MoO₂(H₂O)(BBB)] was used to prepare the complexes, which are nonelectrolytes, monomers and diamagnetic. The i.r. spectral data reveal that they possess acis-MoO₂ structure. The _sym(OMoO) and _asym(OMoO) shifts and the difference between _sym(OMoO) and _asym(OMoO) have been related to an increase in electron density at the molybdenum atom therein.     

Synthesis and biological effects of new derivatives of benzotriazole as antimicrobial and antifungal agents

Derivatives of 2‐aminothiophene‐3‐carbonitrile, 2‐thioxopyridine‐3‐carbonitrile, 1,8‐naphthyridine‐2‐one, thieno[2,3‐b]pyridine‐5‐carbonitrile and thieno[2,3‐d]pyrimidine incorporating with a 1H‐benzo‐triazole moiety or 1,3,4‐thiadiazole derivatives incorporating with a benzotriazol‐1‐ylmethyl group have been synthesized and tested for antimicrobial and antifungal activities. The structures of the newly synthesized compounds have been established on the basis of their analytical and spectral data.     

Synthesis and biological effects of new derivatives of azines incorporating coumarin

New synthetic routes for triazolopyridine, pyridopyrimidine, pyridotriazine, imidazopyridine and pyri‐dazine derivatives incorporating a coumarin moiety with interesting biological activities are reported. Reactions of the 2‐oxo‐4‐(2‐dimethylaminoethenyl)‐2H‐chromene‐3‐carbonitrile ( 4 ) and 2‐amino‐4‐(2‐dimethylaminoethenyl)quinoline‐3‐carbonitrile ( 5 ) with benzotriazol‐1‐yl‐acetic acid hydrazide ( 6 ) affords the substituted [1,2,4]triazolo[1,5‐a]pyrido[3,4‐c]coumarines 9 and quinoline 12 , respectively. Treatment of 4 with 2‐amino‐pyridine, glycine, urea, 3‐aminocrotononitrile or cyanothioacetamide affords 14–18 , respectively. Treatment of 3‐amino‐3,4‐dihydro‐4‐imino‐chromeno[3,4‐c]pyridin‐5‐one (10) with α‐chloro‐acetylacetone affords pyridotriazine derivative 21 . Compound 4 was also coupled with benzenediazonium chloride to afford 2‐oxo‐4‐[2‐oxo‐1‐(phenyl‐hydrazono)‐ethyl]‐2H‐chromene‐3‐carbonitrile 25 . Treatment of the latter product with malononitrile afforded the 1‐phenyl‐3‐(3′‐Cyano‐2′‐oxo‐coumarin‐4′‐yl)‐6‐oxo‐pyridazine‐5‐carbonitrile ( 27 ). The structures of the newly synthesized compounds have been established on the basis of analytical and spectral data.     

Synthesis,EGFR-TK inhibition and anticancer activity of new quinoxaline derivatives

Abstract

Ethyl 4-substituted-3-oxo-quinoxaline-2-carboxylates 3–5 were obtained via alkylation of ethyl 3-oxo-3,4-dihydroquinoxaline-2-carboxylate (1). Compound 1 was heterocyclized using hydrazines, ethylenediamine, and ethanolamine to give pyrazoloquinoxalines 6, 7, diazepinoquinoxaline 8, and oxazepinoquinoxaline 10. The quinoxaline-2-carboxamides 9, 11, 12 were prepared via condensation of compound 1 with different amines. Compound 1 was thiated using Lawesson’s reagent affording quinoxaline-3-thione 13, in fair yield. In addition, the reaction of 4-methyl-3-oxoquinoxaline 3 with some binucleophiles led to a series of new oxoquinoxaline derivatives 14–18. The molecular structure of compounds 1, 3, and 9 was confirmed by X-ray crystallography.

The anti-proliferative activity showed that among all the tested compounds, compounds 3, (IC₅₀ 2.51?±?3.0, 4.22?±?1.6 and 2.27?±?1.9?µM), 11 (IC₅₀ 1.32?±?2.61, 1.41?±?1.23 and 1.18?±?1.91?µM) and 17 (IC₅₀ 1.72?±?1.32, 1.85?±?0.94 and 1.92?±?4.83?µM) showed noteworthy anti-proliferative effects against the three cancer cell lines, HCT116, HePG2 and MCF7, respectively, compared to the reference drugs doxorubicin (IC₅₀ 1.41?±?0.58, 0.90?±?0.62 and 1.01?±?3.02?µM) and erlotinib (IC₅₀ 1.63?±?0.81, 1.57?±?0.62 and 1.49?±?0.54?µM). Compounds 3 (0.899?nM), 11 (0.508?nM) and 17 (0.807) showed strong EGFR inhibitory activity compared to Erlotinib (0.439?nM) and these results are in agreement with the docking study. These results suggest that compounds could probably be promising anticancer agents with EGFR inhibitory activity.     

Thionation of tetrakis[(ethoxycarbonyl)methoxy]tetrathiacalix[4]arenes with Lawesson’s reagent

Tetra- and tri-thioated derivatives of tetrakis[(ethoxycarbonyl)methoxy]tetrathiacalix[4]arenes were synthesized by thionation with Lawesson’s reagent in dry toluene. The prepared compounds’ structures were investigated by FT-IR, ¹H NMR, 2D-NMR, MALDI-TOF-MS, and X-ray crystallography. Correspondence: Omran A. Omran, Chemistry Department, Faculty of Science, Sohag University, Sohag 82524 Egypt.     

Polyoxyethylenated bisphenol-A for breaking water-in-oil emulsions

Polyethylene glycol (PEG) of different molecular weights, namely, 600, 1000 and 4000 g/mol was reacted with bisphenol A to form compounds having different hydrophile–lipophile balances and hence different surface activities. The interfacial tension at the aqueous/benzene interface was determined. It was found that the concentrations of demulsifiers required to cause a minimum interfacial tension are always less than those inducing a maximum demulsification efficiency. The demulsification efficiency of the prepared surfactants in breaking synthetic water in benzene emulsions stabilized by petroleum asphaltenes was evaluated. The data revealed that the demulsification efficiency increases with increasing demulsifier concentration, contact time and hydrophilicity.