Ultrasonic Irradiation Conditions Research Articles

Effect of Ultrasonic Irradiation Conditions on Metal Surface during Multifunction Cavitation

Processing using multifunction cavitation (MFC) has recently enabled functional characteristics to be imparted to various materials. It is possible to process a material surface in the same manner as with conventional water jet (WJ) peening; however, the cavitation bubble temperature is different. To further improve this MFC technology, we examine the surface re-forming of low alloy steel (JIS-SCM435) using MFC with various modes of ultrasonic waves. The ultrasonic equipment used for MFC processing includes dual, single, pulse and frequency modulation (FM) ultrasonic modes. Improvement of the residual stress and corrosion resistance was confirmed for all modes. The dual mode showed the maximum values of residual compressive stress and surface potential. The sound pressure at the machining spot was the highest with dual mode, and the temperature in the bubble generated by the WJ nozzle was highest and the amount of dissolved oxygen was lowest. Improvement of the residual stress and corrosion resistance was promoted because the temperature and pressure in the bubble interior during processing was higher than in the other modes.

Green oxidation protocol: Selective conversions of alcohols and alkenes to aldehydes, ketones and epoxides by using a new multiwall carbon nanotube-based hybrid nanocatalyst via ultrasound irradiation

In this work, design and development of a new economically-efficient and environmentally-benign sonochemical-assisted oxidation protocol by using multiwall carbon nanotubes (MWCNTs) and TiO2 hybrid nanostructure catalyst is reported. The structure, morphology and particle size of the nanostructure catalyst and the products were characterized by various methods such as FT-IR, FE-SEM, EDX, XRD, DTA, GC and GC–MS analyses. The selective oxidations of alcohols to aldehydes, ketones and epoxidation were studied in the presence of MWCNTs/TiO2 at room temperature under ultrasonic irradiation conditions in excellent conversions. This is the first design, preparation, characterization and application of the present nanomaterial and also the first ultrasound-irradiated green oxidation. This novel protocol offers several advantages such as environmentally-benign, high yields, selective oxidations, short reaction times, easily isolation of the products, simple preparation, recoverability and reusability of the nanocatalyst without significant decrease in its activity.

Sonochemically assisted synthesis of N-substituted pyrroles catalyzed by ZnO nanoparticles under solvent-free conditions

An efficient and rapid synthesis of 1,2,3,5-tetrasubstituted pyrrole derivatives from a one-pot multicomponent reaction of amines, 1,3-dicarbonyl compounds, and α-haloketones in the presence of ZnO nanoparticles catalyst under ultrasonic irradiation and solvent-free conditions is described.

Construction of mathematical model of dissolution process of solids under action of ultrasound

An influence of the ultrasound beam on the process, dissolution of solids in liquid solvents is considered: influence of frequency, intensity, velocity of acoustic vibrations, cavitation and acoustic flows on mass transfer process. Experimental researches show that the intensification of dissolution process of solids in liquid solvents under action of ultrasound is influenced by acoustic flows, microflows and under influence of cavitation bubbles. Development of new efficient equipment for solution requires the development of calculation methods of dissolution processes of solids in liquid solvents under conditions of ultrasonic irradiation. Such methods should take into account the characteristics of ultrasonic generators, irradiation frequency of ultrasonic vibrations, power and intensity of ultrasonic vibrations. Mathematical model of dissolution process of the granule is constructed. It identifies the change of size of the granule over time under influence of the source of ultrasonic irradiation. Mathematical model consists of three differential equations used to calculate depending on the ratio of the granule size and the maximum turbulence scale of acoustic flows and for cavitation. The mathematical model will enable use in conducting numerous studies as a basis of equipment calculation methods for dissolution process of granular material.

Mild and Efficient Synthesis of 5‐(2,2‐difluoro‐1‐phenyl cyclopropyl)‐N‐substituted‐1,3,4‐oxadiazol‐2‐amines via Graphene Oxide as Catalyst under Ultrasonic Irradiation Conditions

AbstractWe disclosed herein a series of novel 5‐(2,2‐difluoro‐1‐phenylcyclopropyl)‐N‐substituted‐1,3,4‐oxadiazol‐2‐amines from the reaction of 2,2‐difluoro‐1‐phenylcyclopropane carbohydrazide and various isothiocyanates in the presence of graphene oxide (GO) and 1,8‐diazabicyclo [5.4.0]undec‐7‐ene (DBU) under conventional and ultrasonic irradiation conditions. It was found that the reaction was completed in a short period of time with good to excellent yields by virtue of attributes offered by GO catalyst. Further, the reaction underwent smoothly in ethanol and ionic liquids. Noteworthy, GO can be recycled and reused for five cycles without considerable loss in activity. The oxidative activity and morphology of GO catalyst was confirmed by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR) and cyclic voltammetry (CV) techniques.

Nanosilica supported molybdenum catalyst for the epoxidation of olefins under thermal and ultrasonic irradiation conditions

The chemical modification of spherical sub-100 nm silica nanoparticles with 3-aminopropyltriethoxysilane and subsequent reaction with acacen (the Schiff base ligand derived from the condensation of acetylacetone and ethylenediamine) and MoO2(acac)2 precursor produced MoO2acacen@APTSNPs. The characterization of the obtained material was performed by Fourier transform infrared, inductively coupled plasma optical emission spectroscopy, nitrogen adsorption–desorption measurements, thermogravimetric analysis, and scanning electron microscopy, which indicated that the molybdenum complex is successfully supported on the SCMNPs support. The epoxidation of olefins with tert-butyl hydroperoxide in the presence of MoO2acacen@APTSNPs was carried out with good activities and selectivities under reflux and ultrasonic irradiation conditions.

The synthesis of poly(vinyl chloride) nanocomposite films containing ZrO2 nanoparticles modified with vitamin B1 with the aim of improving the mechanical, thermal and optical properties

In the present investigation, solution casting method was used for the preparation of nanocomposite (NC) films. At first, the surface of ZrO2 nanoparticles (NPs) was modified with vitamin B1 (VB1) as a bioactive coupling agent to achieve a better dispersion and compatibility of NPs within the poly(vinyl chloride) (PVC) matrix. The grafting of modifier on the surface of ZrO2 was confirmed by Fourier transform infrared spectroscopy and thermogravimetric analysis (TGA). Finally, the resulting modified ZrO2 (ZrO2–VB1), was used as a nano-filler and incorporated into the PVC matrix to improve its mechanical and thermal properties. These processes were carried out under ultrasonic irradiation conditions, which is an economical and eco-friendly method. The effect of ZrO2–VB1 on the properties and morphology of the PVC matrix was characterized by various techniques. Field emission scanning electron microscopy and transmission electron microscopy analyses showed a good dispersion of fillers into the PVC matrix with the average diameter of 37–40 nm. UV–Vis spectroscopy was used to study optical behavior of the obtained NC films. TGA analysis has confirmed the presence of about 7 wt% VB1 on the surface of ZrO2. Also, the data indicated that the thermal and mechanical properties of the NC films were enhanced.

Docking, Molecular Dynamics Simulation and Synthesis of New Fenobam Analogues as mGlu5 Receptor Antagonists.

Fenobam is a non-competitive mGluR5 antagonist as an anxiolytic agent. In this research a new series of fenobam analogues containing thiazole moiety instead of imidazole ring were designed and synthesized. The ureido-substituted products were synthesized from reaction of amino thiazole derivatives and isocyanate derivatives in dichloromethane solvent under microwave and ultrasonic irradiation condition. The synthesized compounds structures were established by means of IR, 1HNMR, 13CNMR spectroscopic data. Then, docking calculations were performed on the active site of mGLuR5 and compared to Fenobam as a reference drug by using AutoDock program. The molecular dynamics (MD) simulations were done using GROMACS 5.0.5. Docking studies suggested that all of the compounds possess better binding energy when compared to fenobam. The results of MD simulations might offer the binding mode of ligand (3b), accuracy of docking and the reliability of active conformations which obtained by AutoDock. New derivatives of fenobam were designed and synthesized that have the better insilico results compared to fenobam and will evaluate in future studies.

One-pot synthesis of 2,3-dihydroquinazolin-4(1H)-ones by Fe3O4@SiO2-imid-PMAn nano-catalyst under ultrasonic irradiation and reflux conditions

Fe3O4@SiO2-imid-PMAn efficiently catalyzes the condensation reaction of isatoic anhydride, aldehydes, and primary amines or ammonium salts to afford the corresponding 2,3-dihydroquinazolin-4(1H)-one derivatives under ultrasonic irradiation or reflux conditions. This method gives notable advantages such as operational simplicity, excellent yields, short reaction times, and absence of any tedious workup or purification. In addition, the excellent catalytic performance and the easy preparation, thermal stability, and separation of the catalyst make it a good heterogeneous system and a useful alternative to other heterogeneous catalysts. Also, the aforementioned nanocatalyst can be easily recovered by a magnetic field and reused for subsequent reactions for at least six times without noticeable deterioration in catalytic activity and reaction yield.

Ultrasound irradiation promoted synthesis of bispyrimidine and bispyrazolines as selective adsorbents for the selective removal of Ag(I) and Pb(II) from aqueous solutions

In this paper, a new series of five-membered heterocyclic compounds containing pyrazoline and pyrimidine nucleus were synthesized under both conventional and ultrasonic irradiation conditions. In the first step, bischalcone derivatives were prepared by Claisen-Schmidt condensation of bisaldehydes and acetophenone in alkaline ethanol under conventional and ultrasonic conditions. In the second step, bispyrimidine and bispyrazolines were synthesized by the condensation reaction of bischalcones with thiourea/phenyl hydrazine in an alkaline medium. The ultrasound-assisted synthesis provides excellent yields in short reaction times at room temperature. The structures of the newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, mass and elemental analysis. The new synthesized bispyrimidine and bispyrazoline were used as new adsorbents for the excellent selective removal of silver and lead ions from aqueous mixed metal ion solution containing Cu(II), Co(II), Ni(II), and Zn(II) by batch technique. Also, the quantitative desorption was achieved for lead and silver ions with 0.5 M of HNO3 and HCl solutions, respectively.

Mn(TPPS)] immobilized on ionic liquid-modified silica as a heterogeneous and reusable catalyst for epoxidation of alkenes with NaIO4 under ultrasonic irradiation

Effective epoxidation of alkenes using sodium periodate was accomplished with Manganese (III) tetrakis(p-sulfonatophenyl)porphyrin, [C44H26N4O12S4Na4], supported on ionic liquids-modified silica, Im-SiO2, under ultrasonic irradiation conditions is reported. This heterogeneous catalyst, [Mn(TPPS)@SiO2-Im] was characterized by elemental analysis, scanning electron microscopy (SEM), FT-IR and UV–Vis spectroscopic methods. The synthesized hybrid catalyst was applied for efficient epoxidation of various alkenes with sodium periodate in acetonitrile under ultrasonic irradiation conditions. This solid catalyst can be easily recovered by simple filtration and reused several time without apparent loss of its catalytic activity.

H3PW12O40-catalyzed one-pot synthesis of bis(indole) derivatives under silent and ultrasonic irradiation conditions in aqueous media

A convenient and direct approach has been developed for the preparation of bis(indole) derivatives by one-pot four-component condensing of indole, aldehydes and active methylene compounds in the presence of 12-tungstophosphoric acid in aqueous media under silent and ultrasound methods. The remarkable advantages are the simplicity of the experimental procedures, short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents.

Application of SiO2 nanoparticles with double layer coverage consist of citric acid and l(+)-ascorbic acid for the production of poly(vinyl chloride)/SiO2 nanocomposite films with enhanced optical and thermal properties

Incorporation of SiO2 nanoparticles (NPs) into poly(vinyl chloride) (PVC) matrix to prepare PVC/SiO2 nanocomposites (NCs) can enhance its properties. To achieve improved properties for the NCs, NPs should be dispersed properly and be compatible within the polymer matrix. Therefore, to prevent SiO2 NPs from aggregation, surface modification of NPs was performed by citric acid (CA) and l(+)-ascorbic acid (AA) as biological and environmental friendly coating layers for the first time. This process was carried out under ultrasonic irradiation condition, which is an economical and eco-friendly tool. After that three different amounts of modified SiO2 (SiO2–CA–AA) were inserted into PVC matrix and PVC/SiO2–CA–AA NCs were prepared using solution casting method. The structures and morphology of the prepared NC films were verified by several techniques including Fourier transfer infrared, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, ultraviolet–visible (UV–Vis) spectroscopy and tensile testing. Thermogravimetric analysis confirmed the presence of about 13 wt% modifiers on the surface of SiO2. Microscopic observations showed good dispersity of SiO2–CA–AA NPs in the polymer matrix. Resulting NC films showed more flexibility than pure PVC.

The novel synthetic route of 3,5-dimethyl-1-(3-phenylpropyl)-1H-pyrazole under solid–liquid phase transfer catalysis conditions assisted by an ultrasound application—A study of some kinetic parameters

The kinetic study for synthesis of 3,5-dimethyl-1-(3-phenylpropyl)-1H-pyrazole was studied successfully by reacting the 3,5-dimethyl pyrazole with 1-bromo-3-phenyl propane under phase transfer catalysis and ultrasonic irradiation conditions using aqueous solution of NaOH (5 g or 0.25 g/ml), excess amount of bromobenzene and tetrahexyl ammonium bromide as a phase transfer catalyst. The reaction was carried out at 40 °C under pseudo-first order conditions and was monitored by gas chromatography (GC). Kinetic reaction found to follow ‘pseudo first order’ rate law. From the experimental data, a rate expression had been developed to explain the kinetic behavior of the reaction from which the apparent rate constant (kapp) of the organic phase was attained. The effects of agitation speed, amount of sodium hydroxide, effect of quaternary ammonium salts, amount of catalyst and temperature on the reaction were also studied.

Ultrasound Assisted Synthesis of Some Novel Bis‐Pyridazine Derivatives

Bis‐enaminone 3 was coupled with aryldiazonium chlorides 4a, 4b to afford the bis‐arylhydrazonopropanals 6a, 6b. Compounds 6a, 6b could be utilized for the synthesis of a variety of bis‐(dimethyl 2,3‐dihydropyridazine‐3,4‐dicarboxylate), bis‐(pyridazin‐3(2H)‐one), bis‐(2,3‐dihydropyridazine‐4‐carbonitrile) and bis‐(3‐imino‐2,3‐dihydropyridazine) derivatives, under ultrasonic irradiation. A comparative study of aforementioned reactions was carried out under conventional method as well as under ultrasonic irradiation conditions.

Solvent-free highly regioselective Michael addition of phenytoin to α,β-unsaturated esters in the presence of TBAB under ultrasound irradiation

The highly regioselective C-N bond formation between phenytoin and acrylic/fumaric esters was accomplished. Solvent-free media Michael addition of phenytoin to acrylic esters led to the selective synthesis of N3-substituted phenytoins (as mono-Michael adducts) in the presence of tetrabutylammonium bromide (TBAB) and potassium carbonate under ultrasonic irradiation conditions at room temperature. These reactions produced N1,N3-disubstituted phenytoins (as bis-Michael adducts) at 70 oC. Surprisingly, the addition of phenytoin to fumaric esters, instead of acrylic esters, selectively provided only N3-substituted phenytoins at both room temperature and 70 oC under the same conditions.

An expeditious N,N-dibenzylation of anilines under ultrasonic irradiation conditions using low loading Cu(II)-clay heterogeneous catalyst

A simple one-pot procedure for the direct N,N-dibenzylation of anilines using a catalytic amount of Cu modified montmorillonite-KSF is described. Cu modified montmorillonite-KSF has been proven to be a simple, efficient, mild, convenient, and effective catalyst for the selective benzylation of anilines with benzyl bromide. Cu loading plays a significant role in product yield and solvents were found to control the selectivity. The catalyst is easy to prepare, heterogeneous, stable, and easy to recover.

ChemInform Abstract: An Efficient Ultrasound‐Assisted One‐Pot Chemoselective Synthesis of Pyrazolo[3,4‐b]pyridine‐5‐carbonitriles in Aqueous Medium Using NaCl as a Catalyst.

A simple, convenient and green synthetic protocol for the chemoselective synthesis of pyrazolo[3,4-b]pyridine derivatives via three-component reaction of 3-amino-5-methylpyrazole, ethyl cyanoacetate, and aldehydes catalyzed by sodium chloride under ultrasound irradiation in aqueous medium is described. The method showed remarkable selectivity for pyrazolo[3,4-b]pyridine over dehydrogenated pyrazolopyridines, bis-pyrazolopyridines and pyrazolo[1,5-a]pyrimidine derivatives. The reactions were carried out under both conventional and ultrasonic irradiation conditions. Under ultrasound radiation, the catalytic activity of NaCl was about 15-fold higher as compared to the conventional method. The sonochemical procedure offers several advantages including cleaner reaction profile, use of easily available, cheap and environmentally benign catalyst, high yields, and simple experimental and work-up procedures.

FeCl3-promoted and ultrasound-assisted synthesis of resveratrol O-derived glycoside analogs

Phenol derived O-glycosides were synthesized using a direct and convenient O-glycosidation, starting from acetylated sugars in the presence of FeCl3, an inexpensive, mild and benign Lewis acid catalyst. The reactions were carried out under both conventional and ultrasonic irradiation conditions. In general, improvement in rates and yields were observed when reactions were carried out under sonication compared with conventional conditions leading to the corresponding β-O-glycosides as the major anomer. Post-synthetic transformations of iodophenol intermediates led to new resveratrol O-glycoside analogs in good overall yields.

Ultrasound-Promoted Synthesis of Biologically Active α-Hydroxyphosphonates/ Hydroxyphosphinates Using 1,4-Dimethylpiperazine as a Catalyst

A series of new α-hydroxyphosphonates/phosphinates was prepared using 1,4-dimethylpiperazine as a base catalyst under conventional as well as ultrasonic irradiation conditions by the reaction of 5-bromoindole-3-carboxaldehyde/2-nitrocinnamaldehyde with various phosphonates/phosphinates. The high yields of α-hydroxyphosphonates/hydroxyphosphinates were obtained in less reaction time under the ultrasonic irradiation method as compared with the conventional method. The synthesized compounds were screened for their in vitro and in vivo antioxidant activities, and the bio-screening data revealed that all the tested compounds exhibited good antioxidant activities. The bio-screening data revealed that compound 8e exhibited potent antioxidant activity in both in vitro and in vivo studies while the other compounds exhibited good antioxidant activity.[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text, tables and figures.]