不同形貌ZnO纳米粒子的超声化学法制备与表征

One-dimensional ZnO nanorods and shuttle-like ZnO nanoparticles have been successfully achieved by ultrasonic irradiation of Zn (CH3COO)2 aqueous solution and Zn-NH3 complexcs solution. The obtained ZnO nanoparticles have been characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected area electronic diffraction (SAED). And the formative mechanism of the prepared different morphological ZnO nanoparticles is also discussed under ultrasonic irradiation.     

Mechanism of PtIV Sonochemical Reduction in Formic Acid Media and Pure Water

Sonochemical synthesis of platinum nanoparticles (Pt NPs) in formic acid solutions and pure water was investigated using a 20 kHz ultrasonic irradiation. The obtained results gave new insights on the underneath Pt^IV reduction mechanism in formic acid media under argon and in pure water under Ar/CO atmosphere. It was shown that in pure water sonochemical reduction of platinum ions occurs by hydrogen issued from homolytic water molecule split. Pt^IV ion reduction appears to be a very slow process under argon atmosphere in pure water due to formation of oxidizing species like OH radicals and H₂O₂ leading to reoxidation of intermediate Pt^II ions. Sonochemical reduction is accelerated manifold in the presence of formic acid or Ar/CO gas mixture. Solution and gas‐phase analyses reveal that both CO and HCOOH act as OH^. radical scavenger and reducing agent under ultrasonic irradiation. Their ability to reduce platinum ions at room temperature is enhanced due to the local heating in the liquid shell surround the cavitation bubble. An innovative synthesis route for monodispersed Pt NPs in pure water without any templates or capping agents in the presence of Ar/CO gas mixture is then proposed. Obtained Pt NPs within the range of 2–3 nm exhibited a strong stability towards sedimentation in water. Since Ar/CO atmosphere is the only restriction of the process, this procedure can be applied in various media and is also compatible with a large array of experimental conditions.     

全氟己酮中间体全氟丙酰氟及全氟环氧丙烷的合成研究进展

全氟己酮是优良的灭火剂和清洁剂,环境友好且性能优异。本文对其合成工艺进行探究,指出了以六氟丙烯为原料的合成工艺具有工业化的前景,并对六氟丙烯工艺中的重要中间体六氟丙酰氟及六氟环氧丙烷(HFPO)的合成方法进行了分析,指出分子氧液相氧化六氟丙烯制HFPO及使用鼓泡反应器将HFPO异构化成全氟丙酰氟是最有应用前途的工业合成方法。     

Cycloaddition Reaction of 1,4‐Dihydronaphthalene 1,4‐Epoxide with Cyclooctatetraene: Cope Rearrangement in an Adduct

The reaction of 1,4‐dihydro‐1,4‐epoxynaphthalene with cyclooctatetraene at 130±5° for 14 days gave the four products 2a,3,3a,4,9,9a,10,10a‐octahydro‐4,9‐epoxy‐3,10‐ethenocyclobuta[b]anthracene ( 13 ), 25‐oxanonacyclo[10.10.2.2^5,9.1^14,21.0^2,11.0^3,10.0^4,6.0^13,22.0^15,20]heptacosa‐7,15,17,19,23,26‐hexaene ( 14 ), 5,5a,6,6a,6b,6c,12a,12b,12c,13,13a,14‐dodecahydro‐5,14‐epoxy‐6,13‐ethenocycloocta[3′,4′]cyclobuta[1′,2′:3,4]cyclobuta[1,2‐b]anthracene ( 15 ) and bis‐adduct 16 . The structures of the products were determined by spectroscopic methods. It was observed that adduct 14 undergoes a Cope rearrangement. The Cope rearrangement of this adduct was investigated in the temperature range of ?85° to 100° by NMR spectroscopy.     

Formation of dihydroxyselenides from allylic alcohols and their conversion to β-hydroxy epoxides via substitution of a phenylselenonyl group

Hydroxyselenation of allylic alcohols occurs with high regio- and stereoselectivity to give β,β′-dihydroxyphenylselanyl adducts in high yields. An exception is the reaction of the terminal alcohol, 2-methylprop-2-en-1-ol, which forms only a 1,2-diol product. Generally, the addition is Markovnikov in orientation, but the fact that one anti-Markovnikov addition is observed and that addition to 1,2-disubstituted alkenes shows a strong preference for one regioisomer suggests that an interaction of the allylic alcohol with the selenium atom of the reaction intermediate (which weakens the C_β-Se bond in the intermediate) is also an important factor in determining the preference for addition of the phenylselanyl group to the double bond carbon nearest the allylic alcohol. The hydroxyselenated adducts of allylic alcohols can be readily converted to β-hydroxy epoxides in good yields via oxidation with m-chloroperbenzoic acid to a selenone and subsequent treatment with base. Hydroxyselenation of crotyl acetate and 3-acetoxycyclohexene is more regiocatholic than hydroxyselenation of the corresponding allylic alcohols. It appears that the known selectivity of additions of phenylselanyl chloride to these acetates in organic solvents is lost when water or a Lewis acid complexes to the acetate group.     

Epoxide Formation from Aldehydes and Ketones-A Modified Method for Preparing the Corey-Chaykovsky Reagents

Trimethylsulfoxonium iodide and potassium tert-butoxide in dimethyl sulfoxide (DMSO) is a very efficient process for the multi-kilogram scale preparation of epoxides from aldehydes and ketones.     

Sonochemical immobilization of silver nanoparticles on porous polypropylene

Silver nanoparticles were immobilized on the surface of polypropylene (PP) porous beads by an ultrasound‐assisted reduction method. The structure and properties of the silver–PP composite were characterized with XRD, TEM, HRSEM, EDX, XPS, and Raman spectroscopy. Water‐soluble polymers such as PEG, PVA, and PVP were used as stabilizing agents for preventing the agglomeration of the silver nanoparticles. With PVP, a homogeneous distribution of silver nanocrystals, 50 nm in size, on the PP surface was achieved. The mechanism proposed for the silver anchoring to the inert polymer accounts for a localized melting of the PP. The beads of the silver PP composite demonstrated good stability and high antibacterial activity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1719–1729, 2008     

Sonochemical synthesis of chromenes catalyzed by L-phenyl alanine-attached nano-Fe3O4@SiO2

An efficient multi-component synthesis of 10,10-dimethyl-7-(phenyl)-10,11-dihydrochromeno[4,3-b]chromene-6,8(7H,9H)-diones is described by a one-pot condensation reaction of aldehydes, dimedone and 4-hydroxycoumarin using L-phenyl alanine tethered to nano-Fe₃O₄@SiO₂ under ultrasonic irradiation. The catalyst has been characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX), thermal gravimetric analysis (TGA) and vibrating-sample magnetometer (VSM). Atom economy, wide range of products, high catalytic activity, excellent yields in short reaction times, reusability of the catalyst and low catalyst loading are some of the important features of this protocol.     

Synthesis of Vinyl Sulfones from Aryl Methyl Ketones Under Sonochemical Conditions and Formation of Allyl Sulfones

An efficient synthesis of vinyl sulfones 3a-o from aryl methyl ketones 2 bearing an electron withdrawing group and the phosphonic ester 1 under sonochemical conditions is reported. These compounds are generally obtained as an E/Z mixture. Formation of the allyl sulfones 4 is also observed.     

Sonochemical fabrication of fluorinated mesoporous titanium dioxide microspheres

A sonochemical-hydrothermal method for preparing fluorinated mesoporous TiO₂ microspheres was developed. Formation of mesoporous TiO₂ and doping of fluorine was achieved by sonication and then hydrothermal treatment of a solution containing titanium isopropoxide, template, and sodium fluoride. The as-synthesized TiO₂ microspheres were characterized by X-ray diffraction (XRD), Fourier translation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, photoluminescence spectroscopy (PL), and BET surface areas. The P123 template was removed completely during the hydrothermal and washing steps, which was different from the conventional calcination treatment. The as- synthesized TiO₂ microspheres had good crystallinity and high stability. Results from the photocatalytic degradation of methylene blue (MB) showed that fluorination could remarkably improve the photocatalytic activity of titanium dioxide.     

Sonochemical Processes and Formation of Gold Nanoparticles within Pores of Mesoporous Silica

Mesoporous silica with gold nanoparticles inside its pores was prepared by the soaking and ultrasound-induced reduction method. This new composite was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and high-resolution transmission electron microscopy (HRTEM) techniques. The results showed that nearly spherical-shaped gold nanoparticles, with mean size in diameter of 5.2 nm, are located in the pores, most of which are less than 6 nm in diameter. The ultrasonic irradiation time dependence of optical absorption for the soaked porous solid sample, as suggested by the variation in absorbance at 310 and 544 nm, indicated the reduction of Au (III) ions, and the nucleation and aggregation of gold nanoparticles within pores of mesoporous silica. Additionally, the reaction rates estimated phenomenologically by the absorbance decay at 310 nm for both the porous sample and the corresponding soaking solution presented the enhancement of the sonochemical reduction rate of Au (III) ions within pores of mesoporous silica. It is assumed that the extensive liquid-solid interfacial zones in the pores, due to the high specific surface areas and great porosity of the mesoporous solid, are the major regions where the efficient sonochemical reduction induced by the cavitation takes place. Copyright 2001 Academic Press.     

Fluorinated epoxides: 6. Chemoselectivity in the preparation of 2-[(heptafluoroisopropyl)methyl]oxirane from iodoacetate and iodohydrin precursors

Fluorinated iodoacetate (CF₃)₂CFCH₂CHICH₂OAc (1) (prepared by radical addition of perfluoroisopropyl iodide to allyl acetate) and fluorinated iodohydrin (CF₃)₂CFCH₂CHICH₂OH (2) (prepared from 1) were converted to the corresponding perfluoroalkylated oxirane (CF₃)₂CFCH₂CH(O)CH₂ (3) in the yield of 62%. The chemoselectivity of the oxirane formation appeared to be strongly dependent on the starting compound 1 or 2 and solvent used. Byproducts (CF₃)₂CFCHCHCH₂OH (4) and (CF₃)₂CFCHCHCH₂OAc (5) can form a major part of the products in the formation of epoxide 3.     

超声辐照醋酸乙烯酯的乳液聚合

将超声波引入醋酸乙烯酯(VAc)乳液聚合,实现了醋酸乙烯酯的低温快速聚合。考察了超声功率、乳化剂十二烷基硫酸钠(SDS)和引发剂过硫酸钾(KPS)的浓度对聚合反应的影响。实验结果表明,在VAc 7 mL,H2O 63 mL,w(SDS)1%,c(KPS)4 mmol.L-1,900 W的聚合反应条件下,于25℃反应30 min,VAc的转化率高于80%。     

4-芳亚甲基-2-苯基噁唑-5-酮的超声辐射合成

噁唑酮;4-芳亚甲基-2-苯基噁唑-5-酮的超声辐射合成     

Polyoxygenated Cyclohexene Derivatives from Uvaria rufa

Four new polyoxygenated cyclohexene derivatives, uvarirufone A ( 1 ) and uvarirufols A–C ( 2 – 4 ), along with ten related known compounds, were isolated from the EtOH extract of the aerial parts of Uvaria rufa Bl . Their structures and absolute configurations were determined by in‐depth spectroscopic and spectrometric methods in combination with molecular modeling.     

三唑硫酮氨席夫碱吗啡亚甲胺的超声辐射合成及其生物活性

在超声辐射和常规加热条件下合成了11个未见报道的1-(吗啡啉亚甲基)-3-(3,4,5-三甲氧基苯基)-4-(取代次甲亚胺基)-1,2,4-三唑-5-硫酮. 其结构经1H NMR、13C NMR、IR以及元素分析确证。初步生物活性测试结果表明, 在500 mg/L浓度下化合物对黄瓜花叶病毒(CMV)有一定抑制活性。     

One-Pot Synthesis of Salicylanilides by Direct Amide Bond Formation from Salicyclic Acid Under Microwave Irradiation

A highly efficient protocol for the preparation of aromatic amides is described by the direct reactions between salicyclic acid and aromatic amines in the presence of phosphorous trichloride under microwave irradiation. The method has several advantages over the conventional methods, including operational simplicity, good yield, and reduced reaction time.