Micelle Formation by Sodium Perfluorooctanoate and Decyltrimethylammonium Bromide in 18-Crown-6 + β-Cyclodextrin + Water Systems

The conductances of sodium perfluorooctanoate (SPFO) and decyltrimethylammoniumbromide (DeTAB) have been determined in 18-crown-6 + water (CR + W). -cyclodextrin + water(CD + W) and in CR + CD + W mixtures with a fixed 0.0151 mol dm^–3 concentration of CR andvarying amounts of CD with overall change in the mole fraction range of CD from 0.0 to 0.5 in CR +CD + W mixtures at 30°C. From the conductivity data, the critical micellar concentration (cmc), thedegree of counter-ion association () the free energy of transfer of the surfactant hydrocarbon chainfrom the medium to the micelle (G _HP ⁰ ), and the free energy of transfer of surface contributions(G _S ⁰ ) of SPFO and DeTAB have been computed. It has been found that the micelles of SPFO arestabilized in CR + W mixtures in comparison to pure water, whereas micelles of DeTAB remain comparatively unaffected upon addition of CR in water. On the other hand, micelles of SPFO andDeTAB are denatured upon addition of CD in CR + CD + W mixtures. The denaturation effect isstronger on the micelles of SPFO in comparison to that of DeTAB.     

Mono-Allylation of Gem-Diacetates with Allylsamarium Bromide

Our group have explored the reaction of allylsamarium bromide with a variety of substrates, such as N-(2-aminoalkyl)benzotriazoles1, imines2, nitriles3, diorgano diselenides4, disulfides5, isocyanates6 and nitroalkenes7. Here we wish to report the monoallylation of gem-diacetates with allylsamarium bromide. Gem-diacetates are stable in neutral and basic media, thus they are frequently used to protect aldehydes8. However, the presence of two leaving groups at the same carbon may make carbon …     

Synthesis of Ipratropium Bromide–Related Compounds

Synthesis of ipratropium bromide metabolites is described.     

Tin Mediated Allylation of Aldimines with Allyl Bromide

SyntheticinterestsinhighlyfunctionalizedacyclicandcyclicamineshavecontributedtothewealthofexPerimentalmethodologydeveloPedfortheadditionofcarbanionstothecarbon-nitrogendoublebondofimines.Generally,organometallicreagentsorilltermedi-atesareusedascarbanionsandadditionofallylicorganometallicspeciestothenieconshtutesavaluablemethodforthesynthesisofhomoallylamines.'Amongthese,allyLlithium,'-magnesium,'-zinc,'-boraneandboronate,'-silaneand-stannane'havebeenusedforallylationofdriines.Ontheotherhand,…     

Tetrahydrofuran Ring-opening with Acyloxyphosphonium Bromide Catalyzed by Zinc Bromide: An Effective Method for the Preparation of 4-Bromobutyl Esters

Tetrahydrofuran ring-opening with acyl halides or acid anhydrides is a useful method for preparation of 4-halobutyl esters1. As a result, several methods have been reported for this purpose. For example, the reaction of tetrahydrofuran with sodium iodide and acid chlorides2, the tetrahydrofuran ring-opening with acid chlorides or acid anhydrides catalyzed by samarium triiodide3,4 to give 4-iodobutyl esters; the acylative ring-opening of tetrahydrofuran with acid chlorides catalyzed by yttriu…     

Ammonium Chloride Promoted Palladium-Catalyzed Ullmann Coupling of Aryl Bromide

The Ullmann coupling reaction is one of the most useful methods for the synthesis of symmetrical biaryls. It is usually carried out with copper as a reagent.1 However, it generally requires more than a stoichiomet-ric amount of copper and high reaction temperature. In recent years, various reagents, especially combination of the transition metal with reducing reagents,2-6 were proposed to overcome these problems. For example, Li and co-workers2a,2b have reported the Pd/C and zinc-mediated Ul…     

Ammonium Chloride Promoted Palladium-Catalyzed UIImann Coupling of Aryl Bromide

In water, ammonium chloride was found to promote palladium-catalyzed Ullmann coupling reactions of aryl bromides. In the presence of Pd/C, zinc, NH4Cl, and water, coupling of various aryl bromides was carried out smoothly to afford the corresponding homocoupling products in moderate yields.     

Large Pore Mesoporous MCM-41 Templated from Cetyltriethylammonium Bromide

Following hydrothermal synthesis process, MCM-41 was synthesized by using cetyltfiethylammonium bromide as templating agent. The experimental results showed that MCM-41 with pore diameter in the range of 4-7 nm can be obtained by adjusting nSurf./nSi. It was proved that cetyltriethylammonium bromide is an effective templating agent for increasing pore diameter of molecular sieve MCM-41.     

Palladium Catalyzed Suzuki Cross-coupling Reaction in Molten Tetra-n-butylammonium Bromide

A practical procedure for palladium catalyzed Suzuki cross-coupling reaction of arylboronic acids with aryl halides, including aryl chlorides in molten tetra-n-butylammonium bromide (TBAB) was developed. The reaction exhibits high efficiency and functional group tolerance. The recovery of the catalyst and molten n-Bu4NBr was also investigated.     

Convenient Preparation of 2,3,4, 6-Tetra-O-methyl-α-D-glocopyranosyl Bromide

2,3,4,6-Tetrar-O-methyl-α-D-glucopyranosyl bromide (3) is conveniently prepared by treatment of 2,3,4,6-tetra-O-methyl-D-glucose with HBr. This procedure is easier and produces higher yields than previously reported syntheses.     

Xanthine Biosensor Based on Didodecyldimethylammonium Bromide Modified Pyrolytic Graphite Electrode

ＩｎｔｒｏｄｕｃｔｉｏｎＯｒｄｅｒｅｄｆｉｌｍｓｏｆｗａｔｅｒ ｉｎｓｏｌｕｂｌｅｓｕｒｆａｃｔａｎｔｓｃａｎｂｅｐｒｅｐａｒｅｄｂｙｃａｓｔｉｎｇｔｈｅｉｒｓｏｌｕｔｉｏｎｓｏｒｄｉｓｐｅｒｓｉｏｎｓｏｎｔｏａｓｏｌｉｄｓｕｐｐｏｒｔ .1Ｅｖａｐｏｒａｔｉｏｎｏｆｔｈｅｓｏｌｖｅｎｔａｆｔｅｒｃａｓｔｉｎｇｌｅａｖｅｓｔｈｉｎｆｉｌｍｓｅｌｆ ａｓｓｅｍｂｌｅｄｉｎｔｏｏｒｄｅｒｅｄｓｔａｃｋｏｆｂｉ ｌａｙｅｒ ,ｗｈｉｃｈｉｓｓｉｍｉｌａｒｔｏｂｉｏｌｏｇｉｃａｌｍｅｍｂｒａｎｅｆｏｒｍｅｄｂｙ…     

Mechanism of the Deaquation of Aquopentaaminocobalt（Ⅲ）Bromide

There are two theories,SN1 and SN2, for the mechanism of the deaquation of aquopentaamincobalt(Ⅲ） bromide(AAC-B). Both of the theories are supported by some experimental and calculated data. But there are not any experiments to determine directly the structure of the intermediates at dififferent reaction time.In this paper the structures of the intermediates at different reaction time in deaquation-anation of AACB were determined by extended X-ray absorption fine structure (EXAFS) and the reaction process was studied by the combination of X-ray powder diffraction and EXAFS.It was demonstrated that the deaquation-anation of AACB obeys the SN2 theory.     

Didodecyldimethylammonium Bromide Films Containing Cobalt Phthalocyanine Tetrasulfonate for Electrochemical Catalysis

FlllllSOfWWtCf－IllSOlllblCCllfhCtClllSCCllbCpCCpnfCdbVCCStllgtllClfSOllltlOllOlltOSOlidsurhccandcvnpora！！ng！heorgnnlcS0h，on！，hm工！ngorderednudn…chi！nVcrs！rtchlrcTheseSurbclan！门1！uspr0VldcnuHlqucnnCroon、，！ronn且on！mrc！cclrodcrcnc门ona！idn】nyllllpfOVCtllCCICCtfOCI1CllllCCIpfopCft1CSfosSOllll1llCOOpoffICdSpCCICSSlidlllVCVVflO［IspotClllltllllSCS11111lllytlC：llCllCllllstryl，－DldodCC－ldllllCtllykl1fill互O曾lllllllbfOlllldC（DDAB）WWS且…     

Mechanism of the Deaquation of Aquopentaaminocobalt(III) Bromide

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｏｌｉｄ ｐｈａｓｅｄｅａｑｕａｔｉｏｎ ａｎａｔｉｏｎｒｅａｃｔｉｏｎ[Ｍ(ＮＨ3 ) 5(Ｈ2 Ｏ) ]Ｘ3 → [Ｍ(ＮＨ3 ) 5Ｘ]Ｘ2 +Ｈ2 Ｏ(Ｍ =Ｃｏ3 + ,Ｃｒ3 + ｏｒＲｕ3 + ａｎｄＸ =Ｃｌ- ,Ｂｒ- ｏｒＮＣＳ- )ｈａｓｂｅｅｎｗｉｄｅｌｙｓｔｕｄｉｅｄｓｉｎｃｅｔｈｅｎｉｎｅｔｅｅｎｓｉｘｔｉｅｓ .Ｔｈｅｔｈｅｒｍａｌａｎｄｋｉｎｅｔｉｃｐａｒａｍｅｔｅｒｓｈａｖｅｂｅｅｎｃａｌｃｕｌａｔｅｄａｎｄｔｈｅｄｉｆｆｅｒｅｎｔｍｅｃｈａｎｉｓｍｈａｓｂｅｅｎｐｒｏｐｏｓｅｄａｎｄｄ…     

Alkoxycarbonylation of Allyl Bromide over Palladium Catalyst in Different Reaction Mediums

Supercritical carbon dioxide(scCO2)and its subcritical analogue are now widely used as environ mentally-friendly substitutes of conventional organic solvents in chemical synthesis[1-4]     

Facile Bromination of Aromatic Ethers with Quaternary Ammonium Bromide and Iodosylbenzene

Thedirectintroductionofbromineintotheringsofaromaticethersisawell-establishedprocedure,withbromineinasuitablesolventsuchascarbontetrachloride'oraceticacid2.Recently,quatemaryammoniumsaltswerefoundtobeusedasco-catalystforthedirectbrominationofanilinederivatives3.Thus,quaternaryammoniumtribro-mide,acomplexofquatemaryammoniumbromideandbromine4couldbeappliedforbrominationofaromaticethers5'6.However,theproceduresareverytroublesomeandunsafe.RozenandBrand'reportedthatbrominefluoridecouldbeappliedasa…     

Jahn-Teller Effect on Binary Indium Bromide─An Ab Initio Study

Amongindiumhandes,thestructuralchemistryofthebromidesisrichest.Whilethefirststudycantracebacktothebeginningofthecentury',thebinaryphasediagramhasonlyrecentlybeencompleted'-'duetotheunusualinstabilityofthiscompoundslikeInBr,In5Br=,InZBr3,In.Br7andIner,.Accordingtotheexperiment,thebinaryindiumbromidesareverysensitivetotheair,light,humidityandmechanicalstress.Theoriginoftheunusualinstabilityofthecompoundscreatedgreatinterestamongthetheoreticalchemists.Theresultsbasedonthesemi-empiricalquantU…     

Interfacial Composition,Thermodynamic Properties,and Structural Parameters of [bmim][BF4] + Cetyltrimethylammonium Bromide + Alkanol+Toluene Microemulsions

The interfacial composition, thermodynamic properties and structural characteristics of [bmim][BF₄] + CTAB + alkanol + toluene microemulsions were studied by the method of dilution under varied temperatures (298 K, 308 K, 318 K). The compositions of surfactant and cosurfactant at the interfacial region, the distribution of cosurfactant between the interfacial region and the continuous oil phase have been estimated. The thermodynamics of transfer of cosurfactant from the continuous oil phase to the interface have been evaluated. The structural parameters viz. radii of the droplet (R _e) and the ionic liquid pool (R _IL), the thickness of the interfacial layer (l), the number of droplets (N _d) have also been estimated assuming monodispersity of the spherical droplets.