Presence Of KOH Research Articles

Improvement of renewable transportation fuel properties by deoxygenation process using thermal and catalytic cracking of triglycerides and their methyl esters

Growth of the world energy consumption, depletion of energy sources and global warming related to fossil fuel consumption have increased the attention toward the production of renewable fuels. Conversion of vegetable oil and fats (natural triglycerides) to biofuel is one of the options to produce renewable fuels for the transportation sector, but the yield and quality of products are among the important factors in the process. This paper presents some of the results obtained from the study of deoxygenation and ketonization processes using thermal/catalytic cracking of sunflower oil and its methyl esters for the production of transportation biofuels. Sunflower oil was converted to methyl ester in the presence of KOH through transesterification reaction and was used as a feed for the cracking process. Fuel properties after thermal cracking of sunflower oil and its methyl esters have been compared to determine the benefits of transesterification process as a pretreatment step for the triglycerides. To reduce the oxygen content of the liquid products and improve properties of the fuel after catalytic cracking using HZSM-5, deoxygenation over γ-Al2O3 and ketonization over MnO2/γ-Al2O3 catalysts were examined. Results show that depending on the thermal cracking severity, while the yields of the liquid organic products from thermal cracking of sunflower oil and its methyl esters were almost the same, their acidity vary between 3.78 and 5.41 mg KOH/g for methyl esters and between 66.16 and 123.41 mg KOH/g for triglycerides. The extracted heavier cuts similar to gas oil vary between 5.26% and 22.35% for methyl esters and between 18.39% and 51.03% for triglycerides, which proves the benefits of methyl ester cracking to the original oil cracking. Decarboxylation and ketonization of the liquid products with catalysts reduce the acidity and improve other properties of the fuel to the standard level.

Alkylation, amino(hydroxy)methylation, and cyanoethylation of 5-substituted 4-phenyl-4H-1,2,4-triazole-3-thiols

Reactions of 1,2,4-triazole-3-thiols with 2-bromopropionic acid, 2-bromocaproic acid, ethylene chlorohydrine, chloroacetamide, 3-bromo-4-methoxybenzyl chloride, 2-methoxy-5-acetylbenzyl chloride, and 2-(2-chlorophenoxy)ethyl chloride in the presence of KOH have afforded new 3-sulfanyl-1,2,4-triazoles in high yields. Aminomethylation of 1,2,4-triazole-3-thiols in the presence of formaldehyde has given the corresponding 2-aminomethyl-2H-1,2,4-triazole-3(4H)-thiones. Interaction of triazole-3-thiols with formalin and acrylonitrile has resulted in the formation of N2-hydroxymethyl- and 3-(2-cyanoethyl)sulfanyl derivatives.

Azide–Enolate 1,3‐Dipolar Cycloaddition as an Efficient Approach for the Synthesis of 1,5‐Disubstituted 1,2,3‐Triazoles from Alkyl/Aryl Azides and β‐Ketophosphonates

AbstractA simple procedure to prepare 1,5‐disubstituted 1,2,3‐triazoles efficiently from alkyl/aryl azides and β‐ketophosphonates in the presence of KOH by an azide–enolate 1,3‐dipolar cycloaddition in good yields was developed.

Ultrasound-Promoted Synthesis of 3-(Thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-carboximidamides and Anticancer Activity Evaluation in Leukemia Cell Lines

3-(Thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-carboximidamides were efficiently prepared through a cyclocondensation of thiophenylchalcones with aminoguanidine hydrochloride under ultrasonic conditions in the presence of KOH and ethanol as a green solvent in short reaction times (15-35 min) and good yields (62-95%). All compounds produced were evaluated against the human Jurkat and RS4;11 acute lymphoblastic leukemia cell lines of T- and B-cell origin, respectively, and the K562 myelogenous leukemia cell line. Six compounds presented half maximal inhibitory concentration (IC50) values around 15 µmol L-1 and five compounds presented IC50 values around 40 µmol L-1 for at least one of the three cell lines analyzed. One compound was not significantly cytotoxic, presenting IC50 value > 100 µmol L-1.

Shape-Controlled Synthesis of Palladium-Copper Nanoalloys with Improved Catalytic Activity for Ethanol Electrooxidation

A facile solvothermal strategy is developed for the preparation of nanometer sized Pd-Cu alloy. We can control the morphology of these alloys with the use of ethylene glycol (EG) in the presence of KOH. Namely, by increasing the concentration of KOH/EG, the Pd-Cu alloys with different morphologies from near-spherical nanoparticles (NPs) to nanorods and nanowire networks have been prepared. Among all these alloys, near-spherical Pd-Cu NPs-modified electrodes exhibit the highest catalytic activity (11.7 mA/cm2) and stability toward the electrooxidation of ethanol in comparison with commercial Pd/C-modified ones (2.1 mA/cm2).

Synthesis of functionalized alkynes via palladium-catalyzed Sonogashira reactions

A highly efficient protocol for the copper and phosphine free Sonogashira cross-coupling reactions of aryl iodides with terminal alkynes under aerobic conditions has been developed. Using 1mol% of the palladium-bis(oxazoline) complex, Pd-BOX A, in the presence of KOH, and a CH3CN–H2O solvent system allowed for the cross-coupling reactions to proceed at room temperature or 60°C. This new catalytic system was found to be highly active for the cross-coupling reaction of aryl diiodo substrates with unactivated alkyl alkynes to produce various symmetrical dialkynes, as well as for the cross-coupling of terminal dialkynes with aryl iodides to generate symmetrical disubstituted internal alkynes.

3‐(3,5‐Dimethyl‐1H‐Pyrazol‐1‐yl)‐3‐Oxopropanenitrile as Precursor for Some New Mono‐Heterocyclic and Bis‐Heterocyclic Compounds

3‐(3,5‐Dimethyl‐1 H ‐pyrazol‐1‐yl)‐3‐oxopropanenitrile 1 was used as a cyanoacetylating agent for synthesis of the acetanilide derivative 3. Compound 3 was utilized as a key intermediate for the synthesis of some new mono‐chromene and di‐chromene derivatives 9 and 13, the dihydrazo derivatives 15, and the dithiazole derivatives 18 via the condensation with o‐hydroxybenzaldehyde derivatives, the coupling with aryl diazonium salts, or the reaction with phenyl isothiocyanate in presence of KOH followed by phenacyl bromide derivatives respectively.

Preparation of Activated and Non-Activated Carbon from Conocarpus Pruning Waste as Low-Cost Adsorbent for Removal of Heavy Metal Ions from Aqueous Solution

Conocarpus pruning waste, an agricultural byproduct, was converted into low-cost activated and non-activated carbons and used for the remediation of Cd2+, Cu2+, and Pb2+ from aqueous solutions. The carbonization was carried out at 400 °C, while the activation was carried out in the presence of KOH and ZnCl2. Batch single-solute and multi-solute equilibrium and kinetic experiments were carried out to determine the adsorption capacities of the prepared activated and non-activated carbons, and these were further compared with commercially available activated carbon. The results showed that KOH-activated carbon (CK) outperformed the other activated and non-activated carbons in terms of adsorption efficiency. CK removed >50% of the applied Cd2+ and Cu2+ and 100% of Pb2+ at the initial concentration of 40 mg L-1. Interestingly, the performance of Conocarpus-derived non-activated carbon was better than that of the commercial activated carbon, as observed from the Langmuir maximum adsorption capacities of 65.61, 66.12, and 223.05 µmol g-1 for Cd2+, Cu2+, and Pb2+, respectively. The Pb2+ was the metal most easily removed from aqueous solution because of its large ionic radius. The kinetic dynamics were well described by the pseudo-second order and Elovich models.

Copper-catalyzed one-pot tandem synthesis of unsymmetrical diaryl chalcogenides from two different aryl iodides

Unsymmetrical diaryl chalcogenides were synthesized by a novel one-pot tandem process from two different aryl iodides. A symmetrical diaryl dichalcogenide (ArEEAr, E=Se or Te) was initially obtained by a Cu2O-cataylzed coupling reaction of ArI with elemental selenium or tellurium in the presence of KOH. Without purification, it was subsequently coupled with a different aryl iodide (Ar′I) to give the unsymmetrical diaryl chalcogenides (ArEAr′) in good yields.

Extraction of graphitic carbon quantum dots by hydrothermal treatment commercially activated carbon: the role of cation–π interaction

Graphitic carbon quantum dots (GCQDs) are obtained by hydrothermal treatment of commercially available activated carbon in the presence of KOH. Transmission electron microscope observation indicated narrow particle size distribution between 1 and 6 nm with an average diameter 3.5 nm and high crystallinity of GCQDs. The as-prepared GCQDs exhibited bright yellow luminescence under UV light irradiation and a quantum yield of maximum 11.6 % at the excitation wavelength of 480 nm is achieved. In addition, GCQDs performed very well in the application of bio-imaging. The successful introduction of oxygen-related groups on GCQDs was evident by Fourier transform infrared and X-ray photoelectron spectroscopy measurements. A new mechanism based on hydrothermal induced crystallization and extraction of GCQDs by cation–π interaction is proposed to explain the formation of GCQDs.

Design, Synthesis, and Characterization of 1, 3‐disubstituted‐1,4‐benzodiazepine Derivatives

The 2‐amino‐4′‐flouro‐benzophenone (1) that was reacted with chloroacetylchloride to afford 2‐chloro‐N‐(2‐(4′‐fluorobenzoyl) phenyl)acetamide (2) was subsequently converted to 1,4‐benzodiazepines (3) by the modification of the known hexamethylenetetramine based cyclization reaction developed by Blazevic and Kajfez. Thus, obtained product (3) was reacted with a variety of alkyl halide using KOH in DMF to give 1‐substituted‐5‐(4‐fluorophenyl)‐1H‐benzo[e][1,4]diazepin‐2(3H)‐one (4a, 4b). To achieve 1, 3‐disubstituted 1, 4‐benzodiazepines (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l, 5m, 5n, 5o, 5p, 5q, 5r, 5s, 5t), 1‐substituted‐5‐(4‐fluorophenyl)‐1H‐benzo[e][1,4]diazepin‐2(3H)‐one (4a, 4b) was treated with various aromatic aldehydes in the presence of KOH in toluene.

Alternative Route for the Synthesis of New Derivatives of Benzimidazo[2′,1′:2,3] thiazolo[5,4-d]pyrimidine

A series of new benzimidazothiazolopyrimidines were synthesised through a route involving successive nucleophilic substitution of 5-bromo-2,4-dichloro-6-methylpyrimidine with 2-mercaptobenzimidazole and secondary amines, respectively and eventually cyclisation in the presence of KOH in DMF. The structures of the newly synthesised compounds were characterised by their spectral data and elemental analysis.

Synthesis, structural characterization and biological activities of organotin(IV) complexes with 5-allyl-2-hydroxy-3- methoxybenzaldehyde-4-thiosemicarbazone

The organotin(IV) complexes [MeSnCl(L)] (2), [BuSnCl(L)] (3), [PhSnCl(L)] (4) and [Me2Sn(L)] (5) were synthesized by reacting organotin(IV) chloride(s) with 5-allyl-2-hydroxy-3-methoxybenzaldehyde-4-thiosemicarbazone [H2L], (1)] in presence of KOH in 1:2:1 molar ratio (metal salt: base:ligand). All the complexes have been characterized by elemental analyses, UV-Vis, FT-IR, 1H, 13C and 119Sn NMR spectral studies. The molecular structure of complex 5 has been confirmed by single crystal X-ray diffraction analysis. The ligand, H2L coordinates to Sn(IV) in thiolate form through phenoxide-O, azomethine-N and thiolate-S atoms. The C-Sn-C angle measured from coupling constant 1 J(119Sn, 13C) for dimethyltin(IV) complex 5 is 123.4 ∘. The 2 J(119Sn, 1H) coupling constant values for complex 2 and 5 are 72.4 and 76.3 Hz, respectively. Proposed geometry for five coordinated Sn(IV) atom is a strongly distorted trigonal bipyramid. Biological studies were preformed in vitro against four bacterial strains which have shown better activities and potential as antibacterial agents. Organotin(IV) complexes of 5-allyl-2-hydroxy-3-methoxybenzaldehyde-4-thiosemicarbazone were synthesized and characterized by various physico-chemical methods. Crystal structure of dimethyltin(IV) complex was obtained. Ligand (H2L) acts as dinegative ONS tridentate chelating agent, coordinated to tin(IV) atom via phenolic oxygen, azomethine nitrogen and thiolate sulphur atoms. In vitro antibacterial studies revealed that the complexes possess significant activity.

Synthesis of magnetite films on copper substrate by hydrothermal method

Magnetite (Fe3O4) films on conducting non-magnetic copper substrate were successfully synthesised in a wide temperature range by a simple hydrothermal method. The synthesis utilised FeSO4.7H2O and hydrazine hydrate as starting materials in the presence of KOH for adjusting the pH value to 10. The synthesis was performed in a wide temperature range of 80 to 200°C. The as prepared Fe3O4 films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The XRD patterns of the films showed pure phase of Fe3O4 accompanied by copper substrate peaks. The SEM images showed firm, compact and uniform Fe3O4 films with thickness of ∼10 μm. The VSM results presented in plane anisotropic magnetic properties, which further confirms the formation of Fe3O4 films on the copper substrate and thus endows their potential applications in the future.

Diorganotin(IV) complexes of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone: Synthesis, spectral characterization and crystal structure

Three new diorganotin(IV) complexes of the formulae [Me2Sn(cdet)] (2), [Bu2Sn(cdet)] (3) and [Ph2Sn(cdet)] (4) have been synthesized by the reaction of 3,5-dichloro-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone [H2cdet, (1)] and appropriate diorganotin(IV) chloride in the presence of KOH in absolute methanol. These compounds have been characterized by CHN analyses, UV–Vis, FT-IR, 1H, 13C and 119Sn NMR spectroscopic techniques. The molecular structures of the ligand (1) and its diphenyltin(IV) complex (4) have been determined by X-ray diffraction analysis. The ligand H2cdet (1) remains as the thione form in the solid state. The crystal structure of [Ph2Sn(cdet)] (4) revealed that the ligand is coordinated to central tin(IV) atom as a dinegatively tridentate chelating agent via the phenoxide oxygen atom, the azomethine nitrogen atom and the thiolate sulfur atom. The 119Sn NMR chemical shift for the complexes (2–4) are found to be −177.08 to −169.22ppm, confirming five coordinated tin(IV) centre. X-ray crystal structure showed that the coordination geometry of central tin(IV) atom is distorted trigonal bipyramid. The oxygen and sulfur atoms are in axial positions while two phenyl groups and the azomethine nitrogen atom of the ligand occupy the equatorial positions.

Synthesis, characterization and catalytic, cytotoxic and antimicrobial activities of two novel cyclotriphosphazene‐based multisite ligands and their Ru(II) complexes

Two novel cyclotriphosphazene ligands (2 and 3) bearing 3‐oxypyridine groups and their corresponding Ru(II) complexes (4 and 5) were synthesized and their structures were characterized using Fourier transform infrared, 1H NMR and 31P NMR spectroscopic data and elemental analysis. The Ru(II) complexes were used as catalysts for catalytic transfer hydrogenation of p‐substituted acetophenone derivatives in the presence of KOH. Additionally, the cytotoxic activities of compounds 2, 3, 4, 5 were evaluated against PC3 (human prostate cancer), DLD‐1 (human colorectal cancer), HeLa (human cervical cancer) and PNT1A (normal human prostate) cell lines. Finally the antimicrobial activities of compounds 2, 3, 4, 5 were evaluated against a panel of Gram‐positive and Gram‐negative bacteria and yeast cultures. The complexes showed efficient catalytic activity towards transfer hydrogenation of acetophenone derivatives, especially those bearing electron‐withdrawing substituents on the para‐position of the aryl ring. The compounds were found to have moderate to high cytotoxic and antimicrobial activities, and Ru(II) complexation enhanced both cytotoxic and antimicrobial activities in comparison with the parent compounds. Copyright © 2015 John Wiley & Sons, Ltd.

Facile Synthesis of Nanoporous Carbons with High Surface Area and Their CO2 Adsorption Properties

Abstract New nanoporous carbons were prepared by carbonization of resorcinol–formaldehyde–Pluronic F127 composite in the presence of KOH. The obtained nanoporous carbon possesses 2.4-nm mesopores and high surface area of 3277 m2 g−1. The obtained nanoporous carbon showed a high CO2 adsorption capacity of 6.2 mmol g−1 at 273 K and 745 mmHg because of such high surface area and nanopores larger than 1 nm in size.

Synthesis and Characterization of Ruthenium(II) Complexes Bearing Benzimidazole Ligands: For Transfer Hydrogenation Catalysis

Ru(II) complexes with the general formula [RuCl2(p-cymene)(L1-3)], K1–3, (L1–3: monodentate benzimidazole ligands), [RuCl2(L5–6)(S)], K4–7, (L5–6: tridentate benzimidazole ligands, S: Solvents [methanol or acetonitrile]), and [RuCl2(L5)(L1–2)], K8–9, were synthesized from [RuCl2(p–cymene)]2 dimer and mono- and tridentate benzimidazole ligands. The compounds were characterized by elemental analysis, IR, UV-Vis, and NMR. The synthesized Ru(II) complexes (K1–9) were tested as catalysts for the transfer hydrogenation (TH) of acetophenone to secondary alcohols in the presence of KOH using 2–propanol as a hydrogen source at 82°C. All complexes were active catalysts for TH of acetophenone with good yields under mild conditions (after 60 minutes, yields of up to 97%).

Alkyland arylketone reactions with phenylacetylene promoted by KOH—DMSO superbase: a quantum chemical study

Mechanisms of ethynylation and vinylation of ketones with phenylacetylene in the presence of KOH•5DMSO superbase were studied using the MP2/6-311++G**//B3LYP/6-31+G* approach. The thermal effects and activation barriers to individual reaction stages were evaluated. It was shown that stereoscpecificity of ketone vinylation with PhC≡CH is due to the possibility of isomerization of both carbanion intermediates and enolate anions originating from the final β,γ-unsaturated ketones. The calculated activation energies of the vinylation of substituted ketones are in good agreement with the experimentally observed differences in their reactivity with respect to the addition of phenylacetylene.

ChemInform Abstract: In situ‐Generated Iodonium Ylides as Safe Carbene Precursors for the Chemoselective Intramolecular Buchner Reaction.

AbstractThe ylides are generated from the substrates and Ph‐I(O‐Ac)2 in the presence of KOH and undergo an intramolecular Buchner reaction under catalysis.