- Quantitative Treatment of Micellar Effects upon the Nucleophilicity of Halide Ions
-
Nucleophilic attack upon methyl benzenesulfonate (1) by Cl- or Br- occurs readily in aqueous cetyltrimethylammonium chloride or bromide (CTACl or CTABr, respectively).The increase of rate constant with can be analyzed in terms of the concentration of 1 and halide ion in the micellar pseudophase, and the second-order rate constants in micellar and aqueous pseudophases are similar.
- Al-Lohedan, Hamad,Bunton, Clifford A.,Moffatt, John R.
-
-
Read Online
- Removal of Alkyl Sulfonates Using DABCO
-
During the route development of a midstage clinical candidate, we were challenged with a presence of alkyl sulfonates, which were identified as potential genotoxic impurities in our active pharmaceutical ingredient (API). As a result, we initiated a development effort to identify a method to remove the alkyl sulfonates that would be amenable for scale-up. Herein, we report our effort toward the development of a general approach using DABCO (1,4-diazabicyclo[2.2.2]octane) to remove alkyl sulfonates that is both efficient and convenient from the bench to scale-up.
- Corazzata, Kaitlyn,Langston, Alexander,Lee, Elaine C.,Mo, Shunyan,Rose, Peter J.,Snodgrass, Joseph
-
-
- Chan-Lam-Type C-S Coupling Reaction by Sodium Aryl Sulfinates and Organoboron Compounds
-
A Chan-Lam-Type C-S coupling reaction using sodium aryl sulfinates has been developed to provide diaryl thioethers in up to 92% yields in the presence of a copper catalyst and potassium sulfite. Both electron-rich and electron-poor sodium aryl sulfinates and diverse organoboron compounds were tolerated for the synthesis of aryl and heteroaryl thioethers and dithioethers. The mechanistic study suggested that potassium sulfite was involved in the deoxygenation of sulfinate through a radical process.
- Lam, Long Yin,Ma, Cong
-
supporting information
p. 6164 - 6168
(2021/08/16)
-
- Fabrication of silver-modified halloysite nanotubes and their catalytic performance in rhodamine 6G and methyl orange reduction
-
Halloysite nanotube supported Ag nanoparticles (Ag/HNT) as catalyst for reduction of Rhodamine 6G (Rh6G) and Methyl orange (MO) have been synthesized and tested. 3-glycidyloxyproyltrimethoxysilane and Triethylene tetramine were successfully utilized to mo
- Akhondi, Maryam,Jamalizadeh, Effat
-
p. 136 - 144
(2019/04/13)
-
- Functional Hyper-Crosslinked Polypyrene for Reductive Decolorization of Industrial Dyes and Effective Mercury Removal from Aqueous Media
-
A rigid and valuable hyper-crosslinked polymer (HCP) has been synthesized from the polycyclic aromatic hydrocarbon pyrene: hyper-crosslinked polypyrene (HCPPy). HCPPy was prepared through a simple one-step Friedel-Crafts alkylation reaction that involves ZnBr2-catalyzed crosslinking in the presence of an external crosslinker, bromomethyl methyl ether (BME). Interestingly, the unreacted bromomethyl groups (?CH2Br) on the surface of HCPPy could be quantified, which later aided in modification as per our requirement. We aimed at modifying with disulfide-containing cystamine dihydrochloride (Cys-HCPPy). Cys-HCPPy exhibited an extended π-conjugated system with uniform (~1 μm diameter) morphology and high porosity (specific surface area: 445 m2 g?1). As a fundamental application, the Cys-HCPPy composite was used as a sorbent to remove Hg2+ ions from aqueous media. Thus, at pH 6, the adsorption capacity for mercury ions reached 1124.82 mg g?1 after 24 h. Furthermore, the immobilization of Ag nanoparticles on the surface of Cys-HCPPy (Ag@Cys-HCPPy) enhanced the catalytic properties, which allowed for the reductive decolorization of industrial dyes such as methylene blue, methyl orange, and Congo Red in the presence of NaBH4 as a reducing agent.
- Varyambath, Anuraj,Song, Wen L.,Kim, Il
-
p. 1078 - 1087
(2018/11/23)
-
- Energy and environmental applications of ultrasonically sulfur doped copper-nickel hydroxides with heterostructures
-
A series of sulfur doped copper-nickel hydroxides with heterojunctions were successfully fabricated on nickel foam by adjusting thiourea volume via a facile sonochemical pathway. The effect of volume of thiourea on the final morphology and chemical composition of the hybrids were also investigated by field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy analyses. Furthermore, the electrochemical performance and catalytic activity of the as-obtained hybrids were also investigated. Among the tested electrode, the hybrid material fabricated using 6 ml of thiourea (TU-6) showed outstanding electrochemical properties comprising a high specific capacitance of about 2708 F g?1 at 5 A g?1. In addition, the TU-6 hybrid (catalyst) material displayed remarkable reductive degradation ability towards azo dyes viz., methyl orange (within 8 min) and congo red (within 20 min) in the presence of sodium borohydride (reducing agent) with fast kinetics and good reproducibility, respectively. The exceptional electrochemical performance and excellent catalytic activity of TU-6 hybrid electrode may be attributed to the formation of catalytically active sulfur doped copper-nickel hydroxides (CuS/Ni3S2/NiOOH) three-interface synergistic effect, and unique porous micro-rosette-like texture which increased the diffusion rate and adsorption capacity. The adopted strategy is a simple and generic way for material fabrication to solve the energy and environmental problems.
- Karthik, Namachivayam,Edison, Thomas Nesakumar Jebakumar Immanuel,Atchudan, Raji,Sethuraman, Mathur Gopalakrishnan
-
supporting information
p. 126 - 136
(2017/09/22)
-
- Green synthesis of palladium/titanium dioxide nanoparticles and their application for the reduction of methyl orange, congo red and rhodamine B in aqueous medium
-
Objective: Palladium nanoparticles (Pd NPs) supported on the TiO2 NPs were prepared using Euphorbia thymifolia L. leaf extract. The Pd/TiO2 NPs were characterized by FESEM, EDS, TEM and XRD analysis and were used as nanocatalysts for the reduction of a variety of organic dyes. To the best of the author’s knowledge, this study explains the first report to the synthesis of Pd/TiO2 NPs using Euphorbia thymifolia L. leaf extract. Method: 1.0 G of TiO2 was dispersed in 40 mL of 0.3 Mm PdCl2 solution and sonicated for 30 min. Then, 20 mL of the plant extract was mixed under continuous stirring at 60 °C for 2 h. The prepared Pd/TiO2 NPs were centrifuged, washed and then dried. Results: FESEM imaging showed the formation of NPs in the size range of 19-29 nm. The Pd/TiO2 NPs exhibited high activity towards the reduction of Methyl Orange, Congo red and Rhodamine B in the presence of NaBH4 in aqueous medium during 4, 1 and 54 s, respectively. Conclusion: The synthesis of the Pd/TiO2 NPs by this route is rapid, simple, less time consuming, environmentally safe and compatibility for medical and pharmaceutical applications because of minimizing the use of toxic or hazardous organic solvents and reagents. Furthermore, the biosyenthesized nanocatalyst can catalyze the reduction of organic dyes during short-time and can be recovered and recycled several times without significant loss of activity.
- Maham, Mehdi,Nasrollahzadeh, Mahmoud,Bagherzadeh, Mojtaba,Akbari, Reza
-
p. 787 - 795
(2018/04/24)
-
- Highly efficient and simultaneous catalytic reduction of multiple dyes using recyclable RGO/Co dendritic nanocomposites as catalyst for wastewater treatment
-
Development of a low cost, highly efficient and easily retrievable catalyst with improved reusability is a major challenge in the area of advanced catalysts. In this study, we report a simple one-step approach for the fabrication of a reduced graphene oxide (RGO)/Co dendritic nanocomposite. The structure and morphology of the as synthesized material are thoroughly examined by XRD, Raman, FTIR, TEM, and SEM. The magnetic properties of the RGO/Co dendritic nanocomposite reveal that it exhibits ferromagnetic behavior at room temperature with high saturation magnetization. The catalytic activity of the RGO/Co dendritic nanocomposite was investigated for the reduction of different dyes namely, 4-nitrophenol, methylene blue, methyl orange and rhodamine B individually, and their mixture in the presence of a sufficient amount of NaBH4. RGO/Co dendritic nanocomposite exhibits excellent catalytic activity as compared to the bare Co dendritic structure. The catalyst could be easily separated by an external magnet and recycled magnetically with no major loss of catalytic activity upto five cycles. The high catalytic efficiency, low cost and easy recycle technique make RGO/Co dendritic nanocomposite a proficient catalyst for degradation of organic dyes.
- Sahoo, Prasanta Kumar,Thakur, Dinbandhu,Bahadur,Panigrahy, Bharati
-
p. 106723 - 106731
(2016/11/25)
-
- Recycled carbon (RC) materials made functional: An efficient heterogeneous Mn-RC catalyst
-
Abstract A MnII-Schiff-base catalyst was synthesized and covalently immobilized onto Pyrolytic Carbon surface from waste tyres (PCox), resulting in the heterogeneous catalyst MnII-L@PCox which was evaluated for degradation of methyl orange (MO) using NaIO4 as oxidant. Importantly, no additive as co-catalyst was needed. For comparison, a reference heterogeneous catalyst MnII-L@ACox was also tested, using Activated Carbon (ACox) as carbon matrix. The catalytic and recyclability data of MnII-L@PCox catalyst demonstrate that it is superior, in terms of TONs and TOFs vs. MnII-L@ACox. To study the reaction path, electron paramagnetic resonance spectroscopy was used to monitor the redox evolution of the Mn-centers. Furthermore, a full mapping of the catalytic degradation of MO and product formation was carried out using LC-MS and HPLC. Combining catalytic and spectroscopic data we discuss the protective effect of the PCox matrix on Mn-centers; it allows their rapid redox evolution to higher oxidation states.
- Seristatidou,Mavrogiorgou,Konstantinou,Louloudi,Deligiannakis
-
-
- (E)-Specific direct Julia-olefination of aryl alcohols without extra reducing agents promoted by bases
-
An unprecedented base-promoted direct olefination of aryl alcohols with sulfones via a Julia-type reaction has been described. No extra reductants are needed for Julia reaction since alcohols work as double sources of aldehydes and the hydride. Generally high yields were given for both terminal and highly (E)-selective internal olefins.
- Yao, Chuan-Zhi,Li, Qiang-Qiang,Wang, Mei-Mei,Ning, Xiao-Shan,Kang, Yan-Biao
-
supporting information
p. 7729 - 7732
(2015/05/12)
-
- Efficient degradation of azo dyes using Ag and Au nanoparticles stabilized on graphene oxide functionalized with PAMAM dendrimers
-
Herein, we report the stabilization of silver and gold nanoparticles (Ag/Au NPs) on graphene oxide (GO) functionalized with PAMAM dendrimers. The grafting of the PAMAM dendrimers on GO has been investigated using TGA and Raman spectral studies and the stabilization of the Ag/Au NPs on the dendritic structures has been confirmed using XRD, UV-Vis and FT-IR spectra, SEM and TEM studies. The catalytic activity of the prepared nanocatalysts towards the degradation of organic azo dyes, namely methyl orange and congo red, has been tested. The prepared nanocatalysts were found to exhibit excellent catalytic activity towards the complete degradation of both methyl orange and congo red within only a few seconds.
- Rajesh, Rajendiran,Kumar, S. Senthil,Venkatesan, Rengarajan
-
supporting information
p. 1551 - 1558
(2014/05/06)
-
- Generation and alkylation of 2-boryl allylic sulfone anions
-
The deprotonation and electrophilic trapping of an allylic sulfone substituted at the 2 position by a pinacol boronate results in the formation of the corresponding alkylation products. The ability of the boronate ester to tolerate the sulfonyl carbanion suggests a broader application of the methodology to prepare a wide range of functionalized boronates. The Royal Society of Chemistry.
- Altenhofer, Erich F.,Harmata, Michael
-
p. 2365 - 2367
(2013/06/27)
-
- Spectroscopic (FT-IR, FT-Raman and 1H and 13C NMR) and theoretical in MP2/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels study of benzenesulfonic acid and alkali metal benzenesulfonates
-
The FT-IR, FT-Raman and NMR (1H and 13C) spectra of benzenesulfonic acid as well as lithium, sodium, potassium, rubidium and caesium benzenesulfonates were registered, assigned and compared. The molecular structures of ligand and alkali metal salts were discussed. On the basis of quantum mechanical calculations in MP2/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels the geometric parameters, infrared spectra, NMR spectra, the magnetic and geometric aromaticity indices for acid and alkali metal benzenesulfonates and benzoates were obtained. The effect of alkali metal ions on the electronic charge distribution of benzenesulfonic acid was studied and compared with the alkali metal benzoates and benzoic acid.
- ?widerski,Kalinowska,?wis?ocka,Wojtulewski,Lewandowski
-
-
- Reactive sulfur species: Kinetics and mechanism of the oxidation of aryl sulfinates with hypochlorous acid
-
The mechanism of oxidation of ArSO2- (PhSO2 - and 5-sulfinato-2-nitrobenzoic acid = TNBO2 1-/2-) with HOCl/OCl- has been investigated using the kinetic method. In contrast to previous reports for PhSO2- (for which it was suggested that OCl- and not HOCl was the reactant), the reaction proceeds through a conventional pathway: nucleophilic attack by ArSO2- on HOCl with concomitant Cl- transfer to give a sulfonyl chloride intermediate (ArSO2Cl), which we have identified spectrophotometrically. Remarkably, the rate constant for the reaction of HOCl with ArSO2- is on the order of 10 9 M-1 s-1, larger than the rate constants for corresponding thiolates, and is nearly diffusion-controlled. In contrast, the rate constant for the reaction of OCl- with ArSO2 - is approximately 7 orders of magnitude smaller.
- Ueki, Hisanori,Chapman, Garry,Ashby, Michael T.
-
experimental part
p. 1670 - 1676
(2010/08/05)
-
- Crystalline forms of osanetant
-
The invention relates to crystalline forms of (R)-(+)-N-[[3-[1-benzoyl-3-(3,4-dichlorophenyl)piperidin-3-yl]prop-1-yl]-4-phenylpiperidin-4-yl]-N-methylacetamide and to processes for preparing them.
- -
-
-
- Synthesis of 3-chloro-Δ3-cephem-4-carboxylate by addition/cyclization of allenecarboxylate. Copper(II)-promoted aerobic oxidation of arenesulfinic acids
-
The selective transformation of allenecarboxylate derived from penicillin into 3-chloro-Δ3-cephem-4-carboxylate was successfully achieved by an addition/cyclization reaction with chloride salts in aerobic media containing a copper(II) catalyst, in which copper(II)-catalyzed aerobic oxidation of in situ generated benzenesulfinate ion into less nucleophilic sulfonate ion prior to the nucleophilic addition of the former ion to the allenecarboxylate would completely eliminate the formation of undesired 3-phenylsulfonyl-Δ3-cephem-4-carboxylate. Under similar aerobic conditions, arenesulfinates salts and arenesulfinic acids were smoothly oxidized to the corresponding sulfonate salts and sulfonic acids, respectively.
- Tanaka, Hideo,Kikuchi, Ryo,Torii, Sigeru
-
p. 1391 - 1396
(2007/10/03)
-
- Homogeneous Aqueous Oxidation of Organic Molecules by OxoneR and Catalysis by a Water-Soluble Manganese Porphyrin Complex
-
Peroxymonosulfate (KHSO5) oxidizes a wide variety of water-soluble organic molecules in aqueous solutions, and the reactions are generally more rapid in phosphate buffer (pH 6-7) than in pure water.A water-soluble porphyrin complex, meso-tetrakis(4-N-methylpyridyl)porphyrinatomanganese(III) chloride, catalyzes epoxidation and hydroxylation under neutral pH conditions.
- Zheng, Tu-Cai,Richardson, David E.
-
p. 833 - 836
(2007/10/02)
-
- Micellar Effects upon the Rates of SN2 Reactions of Halide Ions
-
Observed first-order rate constants for reactions of Cl- or Br- with alkyl benzenesulfonate (1a-c) in micelles of cetyltrimethylammonium surfactants (CTAX, X=Cl, Br, OMes, 0.5SO4) increase monotonically with increasing or or halide ion concentration and tend to limiting values.In CTAOMes or (CTA)2SO4, the rate constants go through maxima.The variation of the rate constants with concentrations of surfactant and halide ion can be fitted to an equation that accounts for the distribution of both reactants between water and micelles, i. e., in terms of ion-exchange and mass-action models.The second-order rate constants in the aqueous and micellar pseudophases are similar.
- Al-Lohedan, Hamad A.
-
p. 8226 - 8231
(2007/10/02)
-
- Enolate Structures Contributing to the Transition State for Nucleophilic Substitution on α-Substituted Carbonyl Compounds
-
The high SN2 reactivity of α-halocarbonyl compounds is explained by the lowering of the intrinsic barrier by a major contribution of enolate structure to the transition state.This theoretical conclusion is now shown experimentally.The evidence is as follows: (1) Change in structure of a leaving arenesulfonate ion does not change the rates of attack of benzenesulfonate ion by nearly as much as it changes the equilibrium constants.A charge on the transferring phenacyl group of -0.48 is deduced. (2) The ρ value (-3.9) for attack of substituted thiophenoxides on phenacyl bromide is much more negative than that for attack on methyl iodide (-1.8). (3) A related ρ value is found for reaction of 2,4,6-trimethylphenacyl bromide with thiophenoxides (-2.2), showing a lesser, but still large sensitivity to nucleophile structure where addition to the carbonyl is sterically forbidden.The enolate structure leaves the attacking or leaving nucleophiles with a single electron each instead of the unshared pairs.Thus, the enolate structure is emphesized if the leaving group and the nucleophile readily lose an electron.
- Yousaf, T. I.,Lewis, E. S.
-
p. 6137 - 6142
(2007/10/02)
-
- Micellar Effects on the Reaction of (Arylsulfonyl)alkyl Arenesulfonates with Hydroxide Ion. Microenvironmental and Substituent Effects in the Stern Layer of Cationic Micelles
-
The reaction of the sulfonates p-XC6H4SO2CH(R)OSO2C6H4Y-p 1a-g with hydroxide ion (involving nucleophilic attack at sulfonate sulfur) is accelerated (7-25 times) in the presence of CTAB micelles (32.1 deg C).The kinetic data are analyzed in detail by using the pseudophase ion-exchange (PPIE) model, taking into account partitioning of the reactants between the micellar and aqueous pseudophases and competition between hydroxide ions and detergent counterions for binding to the micelles.Binding constants obtained from the kinetic analysis are compared with those from ultrafiltration experiments.Generally, the PPIE model reproduces the experimental rate constants quite well, except at low detergent concentration (around the cmc).The second-order rate constants for reaction in the micellar pseudophase are 4-12 times smaller than those for reaction in bulk water.Therefore the observed catalysis is purely the result of the high local concentration of both reactants in the micellar pseudophase.The substituent effects for the reaction in the micelles reveal an increased susceptibility for variation of Y.No evidence for orientational effects was found.It is shown that the binding of the sulfonates with the micelles is mainly determined by the presence of the aryl groups.Based on a comparison with kinetic solvent effects on the reaction in 1,4-dioxane-water, it is suggested that the rates in the micellar pseudophase reflect a decrease in micropolarity at the binding sites of the substrate molecules.
- van de Langkruis, Gerard B.,Engberts, Jan B. F. N.
-
p. 4152 - 4157
(2007/10/02)
-
- Process for the preparation of cationic dyestuffs
-
To prepare dyestuffs of the general formula STR1 in which R1 and R2 represent methyl or ethyl, n represents 0 or 1, B represents the divalent radical of a 5-membered or 6-membered heterocyclic ring system and X- represents an anion, and wherein the ring a can be substituted by C1 - to C4 -alkyl radicals, C1 - to C4 -alkoxy radicals or halogen, compounds of the formula STR2 wherein R1, B and n have the meaning indicated above, m represents 0 or 1 and the ring a can be substituted by C1 - to C4 -alkyl, C1 - to C4 -alkoxy or halogen, or of the formula STR3 in which B and R1 have the abovementioned meaning and the ring a can be substituted by C1 - to C4 -alkyl, C1 - to C4 -alkoxy or halogen, are reacted with arylsulphonic acid esters of the formula STR4 wherein R represents hydrogen, C1 - to C4 -alkyl or halogen and R2 represents methyl or ethyl, in the presence of water and acid-binding agents at temperatures of 20°-70° C., and, if appropriate, the arylsulphonate anion is replaced by another anion customary in dyestuff chemistry.
- -
-
-
- Linear polyalkylene ether glycols of high molecular weight
-
Linear polypropylene ether glycols of high molecular weight are made by reacting a linear polypropylene ether glycol of lower molecular weight first with an alkaline agent such as sodium hydroxide or other suitable base to form an alcoholate, and then coupling the alcoholate with a suitable difunctional coupling agent, such as the benzene-sulfonic acid diester of ethylene glycol or with some other suitable arylsulfonic acid diester of a C2 to C6 alcohol, thereby obtaining a 100 percent linear polypropylene ether glycol of a desirably higher molecular weight. Materials so produced find use in an aqueous medium as defoaming agents, thickeners, or emulsifiers, and use as protective colloids to improve the low-temperature stability of polyurethane and other latices.
- -
-
-
- Studies on Sulphochlorination of Paraffins. VIII. Studies on the Hydrolysis of Individual Alkane Sulphochlorides by Sodium Hydroxide
-
The hydrolysis of individual C1-C5 alkane sulphochlorides by sodium hydroxide in dioxane/water (1:1) was kinetically studied at 25 deg C by means of stopped-flow technique, measuring the change of electric conductivity.The rate constants were influenced by steric hindrance, but in all cases were higher than the rate constant for alkaline hydrolysis of benzene sulphochloride, which cannot react according to the elimination-addition (sulphene) mechanism.The reaction enthalpy of the alkaline hydrolysis of four individual alkane sulphochlorides was determined by a simple calorimetric apparatus; the average value amounts to ΔRH = -239 kJ mol-1.
- Hampel, M.,Just, G.,Krebes, W.,Pritzkow, W.
-
p. 987 - 990
(2007/10/02)
-