Sonochemistry Research Articles

Ionic liquids: A green solvent for organic synthesis

Industrial Chemistry in the new millennium is widely adopting the concept of “Green Chemistry” to meet the fundamental scientific challenges of protecting the health as well as environment, while maintaining the commercial viability. Use of Ionic liquids (IL) fit nicely into this bill with remarkably cutting the required reaction time and improving the yields and purity of the desired products. Other three more rapidly emerging areas of Green chemistry are Microwave Irradiation (MI), Phase transfer catalysis (PTC) & Sonochemistry (SC). Green chemistry is defined as the designing of chemical compounds and methods that minimizes or destroyed the use and generation of hazardous substances. The awareness of the said liquid is mainly due to their properties such as non flammability, lack of measurable vapor pressure, and good ability to dissolve organic, organometallic, and even some inorganic compounds. In this regards we report the applications of one of the Green Chemistry technique (Ionic liquid) with respect to Pharmaceuticals.

Experimental investigation of ultrasound/ Fenton’s reagent oxidation process on the degradation rate constant of p- nitrophenol

هدف اصلی این پژوهش بررسی اثربخشی ترکیب روش فنتون و سونوشیمی با فرکانس بالا برای تصفیه پساب شامل p- نیتروفنول (PNP) به عنوان ماده آلاینده است. این روش‌ها برای تخریب PNP در سیستم ناپیوسته تحت شرایط عملیاتی مختلف بر اساس فرآیند افراصوت، فنتون، فراصوت/ پروکسید هیدروژن و فرآیند فراصوت / فنتون مورد استفاده قرار گرفته اند. این راکتور شامل شش ترنسدیوسر فراصوت با فرکانس 7/1 مگاهرتز بود. سه ترنسدیوسر در کف و سه ترنسدیوسر دیگر در دیواره رآکتور قرار داشتند. نتایج نشان داد که تجزیه PNP از واکنش شبه درجه اول تبعیت می کند. ثابت نرخ تخریب برای پارامترهای عملیاتی مختلف شامل pH، توان الکتریکی ورودی به ترنسدیوسرها و غلظت و حجم های مختلف H2O2 و FeSO4 تعیین شد. در شرایط بهینه، بیشترین میزان تخریب PNP برای ترکیب فراصوت و واکنش فنتون (min-1 166/0) با ضریب هم افزایی 165/1 بدست آمد. اولویت های بعدی مربوط به فنتون، فراصوت/ پراکسید هیدروژن و فراصوت با ثابت نرخ تخریب min-1 137/0، 0107/0 و 0055/0 بود. بنابراین فرآیند فراصوت / فنتون دارای بالاترین توانایی برای تخریب PNP بود، زیرا فراصوت می تواند واکنش فنتون را برای تولید رادیکال های هیدروکسیل تشدید کند.

Using novel methods (microwave and sonochemistry) for converting biomass to biofuels

Using novel methods (microwave and sonochemistry) for converting biomass to biofuels

Structural evolution, growth mechanism and photoluminescence properties of CuWO4 nanocrystals

Copper tungstate (CuWO4) crystals were synthesized by the sonochemistry (SC) method, and then, heat treated in a conventional furnace at different temperatures for 1h. The structural evolution, growth mechanism and photoluminescence (PL) properties of these crystals were thoroughly investigated. X-ray diffraction patterns, micro-Raman spectra and Fourier transformed infrared spectra indicated that crystals heat treated and 100°C and 200°C have water molecules in their lattice (copper tungstate dihydrate (CuWO4·2H2O) with monoclinic structure), when the crystals are calcinated at 300°C have the presence of two phase (CuWO4·2H2O and CuWO4), while the others heat treated at 400°C and 500°C have a single CuWO4 triclinic structure. Field emission scanning electron microscopy revealed a change in the morphological features of these crystals with the increase of the heat treatment temperature. Transmission electron microscopy (TEM), high resolution-TEM images and selected area electron diffraction were employed to examine the shape, size and structure of these crystals. Ultraviolet–Visible spectra evidenced a decrease of band gap values with the increase of the temperature, which were correlated with the reduction of intermediary energy levels within the band gap. The intense photoluminescence (PL) emission was detected for the sample heat treat at 300°C for 1h, which have a mixture of CuWO4·2H2O and CuWO4 phases. Therefore, there is a synergic effect between the intermediary energy levels arising from these two phases during the electronic transitions responsible for PL emissions.

Comparison of different methodologies for obtaining nickel nanoferrites

Nickel nanoferrites were obtained by means of four different synthetic wet-routes: co-precipitation (CP), sonochemistry (SC), sonoelectrochemistry (SE) and electrochemistry (E). The influence of the synthesis method on the structural and magnetic properties of nickel ferrite nanoparticles is studied. Although similar experimental conditions such as temperature, pH and time of synthesis were used, a strong dependence of composition and microstructure on the synthesis procedure is found, as electron microscopy, X-ray diffraction and Mössbauer spectroscopy studies reveal. Whereas by means of the CP and SC methods particles of a small size around 5–10nm, respectively, and composed by different phases are obtained, the electrochemical routes (E and SE) allow obtaining monodisperse nanoparticles, with sizes ranging from 30 to 40nm, and very close to stoichiometry. Magnetic characterization evidences a superparamagnetic behavior for samples obtained by CP and SC methods, whereas the electrochemical route leads to ferromagnetic ferrite nanoparticles.

Cluster Coordination and Photoluminescence Properties of α-Ag2WO4 Microcrystals

In this paper, we report our initial research to obtain hexagonal rod-like elongated silver tungstate (α-Ag(2)WO(4)) microcrystals by different methods [sonochemistry (SC), coprecipitation (CP), and conventional hydrothermal (CH)] and to study their cluster coordination and optical properties. These microcrystals were structurally characterized by X-ray diffraction (XRD), Rietveld refinements, Fourier transform infrared (FT-IR), X-ray absorption near-edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) spectroscopies. The shape and average size of these α-Ag(2)WO(4) microcrystals were observed by field-emission scanning electron microscopy (FE-SEM). The optical properties of these microcrystals were investigated by ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) measurements. XRD patterns and Rietveld refinement data confirmed that α-Ag(2)WO(4) microcrystals have an orthorhombic structure. FT-IR spectra exhibited four IR-active modes in a range from 250 to 1000 cm(-1). XANES spectra at the W L(3)-edge showed distorted octahedral [WO(6)] clusters in the lattice, while EXAFS analyses confirmed that W atoms are coordinated by six O atoms. FE-SEM images suggest that the α-Ag(2)WO(4) microcrystals grow by aggregation and the Ostwald ripening process. PL properties of α-Ag(2)WO(4) microcrystals decrease with an increase in the optical band-gap values (3.19-3.23 eV). Finally, we observed that large hexagonal rod-like α-Ag(2)WO(4) microcrystals prepared by the SC method exhibited a major PL emission intensity relative to α-Ag(2)WO(4) microcrystals prepared by the CP and CH methods.

Efficient Sonochemistry through Microbubbles Generated with Micromachined Surfaces

Effizienz und Steuerungsfähigkeit sonochemischer Reaktionen steigert der Einsatz von Siliciumoberflächen mit Vertiefungen, in die Gas in einer Weise eingebracht werden kann, dass es auf Ultraschallbehandlung hin als Mikroblasenstrom freigesetzt wird (siehe Bilder). Um die chemisch aktiven Mikroblasen zu erhalten, sind weit geringere Ultraschallintensitäten erforderlich als in entsprechenden üblichen Reaktoren.

ChemInform Abstract: Organic Sonochemistry: A New Interpretation and Its Consequences.

ChemInform Abstract: Organic Sonochemistry: A New Interpretation and Its Consequences.

Syntghesis and Cheracterization of PdAg Nanoparticles as Oxygen Electrocatalyst in Acidic Med.ium

PdAg electrocatalyst was prepared following two d~fferent methods, i.e. borohydride reduction of metallic ions and sonochem- istry. X-ray dzffraction (XRD) and transmission electron microscorn (TEM) characterizations indicate the formation of crystalline PdAg particles with an average particle size of 10 nmfrom chemical reduction, and 12 nmfrom sonochemistry. The electrocatalytic activiw of PdAg, for the owgen reduction reaction (ORR) was characterized using cyclic voltammetry (CV), rotating disk electrode (RDE) and elec- trochemical impedance spectroscom (EIS), in 0.5M H2SOJ Mass-transfered-corrected Tafel plots show an enhancement ofthe electro- catalytic activily associated to the incorporation of silver to palladium. EIS diagrams ofPdAg electrocatalyst present one or two time con- stants depending on the electrode potential, E. The E at which appears the second time constant depends on the method of catalyst prepa- ration. The dzfference in E was attributed to the dtfferent crystalline percentage due to the catalyst preparation method.

S4-1 New Development of Sonochemistry : A case from the electrochemistry and photocatalytic reactions under ultrasonication(Symposium (4) New Development of Sonochemistry)

S4-1 New Development of Sonochemistry : A case from the electrochemistry and photocatalytic reactions under ultrasonication(Symposium (4) New Development of Sonochemistry)

Sonochemistry: Past, Present and Future

AbstractFor Abstract see ChemInform Abstract in Full Text.

Advances in Sonochemistry, Volume 2

<i>Advances in Sonochemistry, Volume 2</i>

Advances in Sonochemistry, Volume I

First Page

Book Review: Sonochemistry: The Uses of Ultrasound in Chemistry. Edited by T. J. Mason

Book Review: Sonochemistry: The Uses of Ultrasound in Chemistry. Edited by T. J. Mason

Sonochemistry and additives

Sonochemistry and additives

Sonochemistry: The Ultrasound and the Fury

Sonochemistry: The Ultrasound and the Fury

Sonochemistry, theory, applications and uses of ultrasound in chemistry, by Timothy J. Mason and J. Phillip Lorimer, Wiley-Interscience, New York, 1989, 252 pp. Price: $87.95

Sonochemistry, theory, applications and uses of ultrasound in chemistry, by Timothy J. Mason and J. Phillip Lorimer, Wiley-Interscience, New York, 1989, 252 pp. Price: $87.95

Sonochemistry: theory, applications and uses of ultrasound in chemistry

Sonochemistry: theory, applications and uses of ultrasound in chemistry

ChemInform Abstract: Organic Sonochemistry. New Ultrasonically Accelerated Reactions Involving Lithium.

ChemInform Abstract: Organic Sonochemistry. New Ultrasonically Accelerated Reactions Involving Lithium.

ChemInform Abstract: Organic Sonochemistry. Ultrasonic Acceleration of the Reaction of Dicarbonyls with Trimethylchlorosilane in the Presence of Zinc.

AbstractDie reduktive O‐Silylierung des Chinons (I) bzw. des 1,2‐Diketons (III) verläuft unter Ultrabeschallung schneller als unter üblichen Bedingungen und liefert durchweg höhere Ausbeuten der Silyl‐ Derivate (II) bzw. (IV).