紫外吸收试剂对反相液相色谱-间接紫外检测法分析烷基磺酸盐的影响

研究了不同背景紫外吸收试剂对无紫外光吸收的烷基磺酸盐检测的影响。采用反相C18色谱柱的高效液相色谱-间接紫外检测法,以背景紫外吸收试剂-有机溶剂为流动相分离烷基磺酸盐。研究不同背景紫外吸收试剂对分离检测烷基磺酸盐的影响规律和分离机理。结果表明,不同类型的背景紫外吸收试剂测定烷基磺酸盐的色谱峰类型不同。阳离子型背景紫外吸收试剂测定烷基磺酸盐时,样品峰均为正峰;阴离子型和两性离子型背景紫外吸收试剂时,样品峰均为倒峰。比较不同的背景紫外吸收试剂,发现采用阳离子型紫外吸收试剂测定烷基磺酸盐的色谱峰更好,其中以咪唑离子液体最佳,检测响应值最高。     

Benzylic-acetoxylation of alkylbenzenes with PhI(OAc)2 in the presence of catalytic amounts of TsNH2 and I2

Treatment of alkylbenzenes with (diacetoxyiodo)benzene in the presence of catalytic amounts of p-toluenesulfonamide or p-nitrobenzenesulfonamide, and molecular iodine in 1,2-dichloroethane at 60 °C gave the corresponding (α-acetoxy)alkylbenzenes in good to moderate yields. The present reaction is a simple method for the introduction of an acetoxy group to the benzylic position of alkylbenzenes.     

Synthesis and Characterization of the Mixed‐Linker Copper(II) Coordination Polymer [Cu(HO3PC6H4SO3)(C10N2H8)]·H2O

A new copper(II) phosphonatobenzenesulfonate incorporating 4,4′‐bipyridine (4,4′‐bipy) as auxiliary ligand has been discovered through systematic high‐throughput (HT) screening of the system Cu(NO₃)₂·3H₂O/H₂O₃PC₆H₄SO₃H/4,4′‐bipy using different solvents. The hydrothermal synthesis of [Cu(HO₃PC₆H₄SO₃)(C₁₀H₈N₂)]·H₂O ( 1 ) was further optimized by screening various copper(II) salts. The crystal structure of 1 was determined by single‐crystal X‐ray diffraction and unveiled the presence of isolated sixfold coordinated Jahn–Teller‐distorted Cu²⁺ ions. The isolated CuN₂O₄ octahedra are interconnected by phosphonate and sulfonate groups to form chains along the c‐axis. The organic groups, namely phenyl rings and 4,4′‐bipy molecules cross‐link the chains into a three‐dimensional framework. Water molecules are found in the narrow voids in the structure which are held by weak hydrogen bonds. Upon dehydration, the structure of 1 undergoes a phase transition, which was confirmed by TG measurements and temperature dependent X‐ray powder diffraction. The new structure of 1‐h was refined with Rietveld methods. Detailed inspection of the structure revealed the directional switching of the Jahn–Teller distortion upon de/rehydration. Weak ferro‐/ferrimagnetic interactions were observed by magnetic investigations of 1 , which switch to antiferromagnetic below 3.5 K. Compounds 1 and 1‐h are further characterized by thermogravimetric and elemental analysis as well as IR spectroscopy.     

Formation of the bisulfite anion (HSO3–, m/z 81) upon collision‐induced dissociation of anions derived from organic sulfonic acids

In the negative‐ion collision‐induced dissociation mass spectra of most organic sulfonates, the base peak is observed at m/z 80 for the sulfur trioxide radical anion (SO₃^–·). In contrast, the product‐ion spectra of a few sulfonates, such as cysteic acid, aminomethanesulfonate, and 2‐phenylethanesulfonate, show the base peak at m/z 81 for the bisulfite anion (HSO₃^–). An investigation with an extensive variety of sulfonates revealed that the presence of a hydrogen atom at the β‐position relative to the sulfur atom is a prerequisite for the formation of the bisulfite anion. The formation of HSO₃^– is highly favored when the atom at the β‐position is nitrogen, or the leaving neutral species is a highly conjugated molecule such as styrene or acrylic acid. Deuterium‐exchange experiments with aminomethanesulfonate demonstrated that the hydrogen for HSO₃^– formation is transferred from the β‐position. The presence of a peak at m/z 80 in the spectrum of 2‐sulfoacetic acid, in contrast to a peak at m/z 81 in that of 3‐sulfopropanoic acid, corroborated the proposed hydrogen transfer mechanism. For diacidic compounds, such as 4‐sulfobutanoic acid and cysteic acid, the m/z 81 ion can be formed by an alternative mechanism, in which the negative charge of the carboxylate moiety attacks the α‐carbon relative to the sulfur atom. Experiments conducted with deuterium‐exchanged and deuterium‐labeled analogs of sulfocarboxylic acids demonstrated that the formation of the bisulfite anion resulted either from a hydrogen transfer from the β‐carbon, or from a direct attack by the carboxylate moiety on the α‐carbon. Copyright © 2012 John Wiley & Sons, Ltd.     

二氧化硅担载Preyssler杂多酸上苯和1-癸烯的烷基化反应:利用表面响应方法进行统计设计(英文)

The response surface method (RSM) was applied to study the liquid phase alkylation of benzene with 1-decene catalyzed by means of silica supported Preyssler heteropoly acid. A three step experimental design was developed based on the central composite design (CCD). Catalyst loading, catalyst mass percent, and benzene to 1-decene molar ratio were used to optimize 1-decene conversion and linear alkylbenzene (LAB) yield. The results indicated that the quadratic model was significant for these two responses. The experimental results revealed that all variables had positive effect on 1-decene conversion. While increasing the catalyst loading tends to decrease LAB yield. Benzene to 1-decene molar ratio was found to be the most important factor that influenced LAB yield with a positive effect. Design expert software suggested several optimized solutions, among them the best choice was to use 31% catalyst loading, benzene to 1-decene molar ratio of 13, and catalyst percent of 3.6 wt% for obtaining 100% conversion and 88% LAB production yield.     

Freely dissolved concentrations of anionic surfactants in seawater solutions: Optimization of the non-depletive solid-phase microextraction method and application to linear alkylbenzene sulfonates

A solid-phase microextraction method (SPME) has been optimized for the analysis of freely dissolved anionic surfactants, namely linear alkylbenzene sulfonates (LAS), in seawater. An effect of the thermal conditioning treatment on the polyacrylate fiber coating was demonstrated for both uptake kinetics and sorption isotherm linearity. Thermal conditioning at 120 °C yielded linear sorption isotherms and reproducible SPME measurements for several individual LAS compounds, with detection limits at the low microgram per liter range. Sorption of LAS to the conditioned SPME fiber was independent of LAS co-solutes in mixtures. The method has been applied to study the precipitation of LAS in seawater, and solubility data for a wide range of individual LAS constituents is presented for the first time. Hence, the developed SPME method for the anionic LAS has shown to be a useful tool in complex matrices. The advantage of the SPME analyses in complex matrices is, besides its simplicity, that it also leads to clean extracts for chromatographic analyses.     

Transition metal- and oxidant-free sulfonylation of 1-sulfonyl-1H-1,2,3-triazoles to enols for the synthesis of sulfonate derivatives

A novel and convenient protocol for the synthesis of sulfonate derivatives via DABCO-catalyzed direct sulfonylation of 1-sulfonyl-1,2,3-triazoles to different enols has been established. This synthetic route could effectively avoid the use of transition metal catalysts and extra oxidants, and the target products could be obtained in good to excellent yields (75–86%) with wide substrate scope under mild conditions at low-catalyst loadings, which would provide a facile and practical access to enol sulfonates. Furthermore, the use of the resulting enol sulfonates for the C–C bond formation has been demonstrated via Suzuki-Miyaura, Sonogashira, and Heck cross-coupling reaction.     

Long-wavelength fluorescence polarization immunoassay for surfactant determination

A new homogeneous fluoroimmunoassay method based on the use of dynamic long-wavelength fluorescence polarization is presented here for the first time. This methodology, which is applied to the determination of linear alkylbenzenesulfonates (LASs) in water samples, involves the use of a new long-wavelength tracer synthesized from the oxazine dye Nile Blue (NB) via a carbodiimide method. This tracer exhibits fluorescent properties at λ_ex 626 and λ_em 674 nm. The variation of fluorescence polarization with time is followed using the T-format configuration of the spectrofluorimeter and the analytical parameter used is the initial rate, which is measured in only 0.7 s. The dynamic range of the calibration graph is 0.05-4.7 mg/L, with a detection limit of 0.03 mg/L. The precision, expressed as relative standard deviation was assayed at 0.05 and 1 mg/L, giving values in the range 7.6-9.1%. Other anionic, cationic and non-ionic surfactants were tolerated at much higher concentration levels than that of the analyte. The method has proven its practical usefulness for the analysis of water samples, in which only a solid phase extraction step is necessary. Recoveries ranged from 80.8 to 119.8%, with a mean value of 100.8%.     

Iron‐catalyzed cross‐coupling of heteroaromatic tosylates with alkyl and aryl Grignard reagents

An Fe(III)‐catalyzed cross‐coupling of N‐heteroaromatic tosylates with aryl and alkyl Grignard reagents is presented. The reaction proceeds at ?20°C to room temperature with short reaction time (15–30 min.), and the corresponding products are obtained with moderate to high yields. In particular, low‐cost and abundantly available FeCl₃ or Fe(acetylacetonate)₃ catalyze the reaction without other special ligands. All tested N‐heteroaromatic tosylates that are available including pyridine and pyrimidine derivatives were subject to the reaction, resulting in the expected products. Copyright © 2015 John Wiley & Sons, Ltd.     

Oxidation of dyes by manganese tetraphenyl porphyrin activated peroxy bleach

The oxidation of a number of dyes in predominantly aqueous systems by tetraphenylporphyrinato manganese(III) imidazole, MnTPP(Im), activated peroxy bleach has been studied in the context of application in detergent systems. Dyes with an olefinic linkage in the chromophoric group are readily oxidized by perborate even in the absence of the activator. On the other hand, dyes with an azo linkage are resistant to oxidation and are bleached only to a limited extent (25%) even by MnTPP(Im) activated perborate. In the presence of a surfactant, alkylbenzene sulphonate, bleaching is further inhibited by micellar solubilization of the dyes. Sulphonation of MnTPP(Im) only marginally improves the bleaching efficiency in presence of the surfactant. MnTPP(Im) is also destroyed by perborate in the absence of the substrate. In view of these limitations, the metalloporphyrin activated peroxy bleach system is not promising for application in detergent systems. Attempts have also been made to explain the difference in the behaviour of different substrates on structural consideration.