取代水杨醛Schiff碱金属配合物催化氧化脱硫性能

以水杨醛类Schiff碱为配体,与Co(NO_3)_2、Cu(NO_3)_2反应合成6种Salen(M)型配合物Ⅰ～Ⅵ。以1-己硫醇、二丁基硫醚和2-甲基噻吩为模型化合物配制模拟油体系,考察了配合物Ⅰ～Ⅵ的催化氧化脱硫性能,并分析了配合物结构与氧化脱硫性能的关系。结果表明,6种配合物在75 min时的总脱硫效果为Ⅵ>Ⅴ>Ⅳ>Ⅰ>Ⅲ>Ⅱ,Ⅵ的总脱硫率为31.9%。对1-己硫醇及二丁基硫醚脱除效果最佳的是Ⅴ,脱除率分别为74.2%和65.1%;对2-甲基噻吩脱除效果最好的是Ⅰ,脱除率为26.8%。构效关系研究表明,中心金属离子与O_2的配位能力越强,配体的共轭体系越大、电子云密度越高,配合物的脱硫性能越好;通过IR和离子色谱对单一硫化物模拟油体系氧化前后的产物进行分析发现,硫化物氧化后皆生成相应的砜类或亚砜类,且1-己硫醇和二丁基硫醚被进一步氧化生成SO_3~(2–)或SO_4~(2–)。     

Superabsorbent hydrogel based on modified polysaccharide for removal of Pb2+ and Cu2+ from water with excellent performance

This contribution describes the absorption percentage of Pb²⁺ and Cu²⁺ from water by a superabsorbent hydrogel matrix (SH) made from an anionic polysaccharide copolymerized with acrylic acid (AAc) and acrylamide (AAm). Metal‐absorption tests, upon sequential pH variation, indicated that the SH has pH‐sensitivity for the absorption of both metals from solution, attributed to the functional ionic groups (? COOH) present in the AAc and arabic gum (AG) segments. At the pH 5.0, the SH exhibited good absorption capacity: 73.10% for Pb²⁺, 81.99% for Cu²⁺ in water and 63.64% for Pb²⁺, and 76.67% for Cu²⁺ in saline water with 0.1 mol kg^?1 ionic strength. A replicated 2² full factorial design with a central point was built to evaluate the maximum absorption capacity of the metals into the SH. It was found that both the interaction and main effects of the pH and the initial concentration of metal solution on absorption percentage of the metals were statistically significant. Surface response plots indicated that the absorption capacity of both metals into the SH may be appreciably improved by using the solutions with lower initial concentration of metal and with higher pH values. Metal‐absorption results demonstrated that the SH is a convenient material for absorption of Pb²⁺ and Cu²⁺ from pure aqueous and saline aqueous environments. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Simulation of Fe-Al compounds developed during single superphosphate manufacture

In order to analyse iron phosphate complexes and gel-like phases encountered in the single superphosphate process, experiments were performed with a free-Al, Fe apatite crystal of Durango from Mexico phosphate rock and sulfuric acid. Reaction products were studied by X-ray diffraction and surface analysis methods namely X-ray photoelectron spectroscopy and scanning electron microscopy. Results show that in a free Al, Fe-system, part of the Ca(H₂PO₄ )₂.H₂O (MCPM) forms before precipitation of any CaSO₄(CS) and gel-like phase such H₂SO₄.yH₃PO₄.xH₂O is formed. When iron is added, the precipitation rate of (CS) and (MCPM) increases and Fe₃(H₃O)H₈(PO₄)₆.6H₂O is formed. When Fe and Al are added, a gel-like phase is quickly formed with a molar ratio that changes with time and develops into crystalline compounds. The composition of this gel may be represented as a mixture of two phases: H₂SO₄.yH₃PO₄.xH₂O and a gel containing Al-Fe-Si.     

Electrochemical investigations of copper behaviour in different cupric complex solutions: Voltammetric study

The electrochemical behaviour of copper has been investigated in different cupric complex solutions by cyclic voltammetry. In pyridinic and picolinic solutions the reduction of cupric complex occurred in two stages leading to Cu(I) and Cu(0), respectively. The electrodeposited copper is oxidized in two steps leading to Cu(I) and Cu(II) as in ammoniacal cupric complex solutions. In glycine, alanine, sulfamic acid and ethylenediamine solutions, the cuprous complex is an intermediate in the cupric complex reduction but it is not detected during the oxidation of the electrodeposited copper in these solutions. In EDTA and triethanolamine solutions, the cuprous complex is not observed. The rate of copper etching was determined in pyridinic and ammoniacal cupric solutions and was shown to be faster in ammoniacal cupric solutions than in the pyridinic solutions.     

Effect of chromium aging on the structural and thermal properties of chromium polyacrylate

The effects of aging time of Cr(III) solutions on the structural, thermal, magnetic, and morphological properties of chromium polyacrylate complexes were studied. Chromium retention was found to increase with longer aging periods. IR spectra revealed the formation of polychelate structures with noticeable changes on aging. The interaction of multivalent, polynuclear Cr(III) species with the polymer backbone resulted in a decrease in thermal stability for the complexes prepared from olated chromium solutions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 490–493, 2005     

Studies on polyacrylates containing pendant ligand with carbonyl and hydroxyl functions and their divalent metal complexes

A series of monomers were prepared by reacting (meth)acryloyl chloride with 2,4‐dihydroxybenzophenone, 2,4‐dihydroxybenzaldehyde, and 2,4‐dihydroxyacetophenone, respectively. The monomers were polymerized in dimethylformamide (DMF) at 70°C using benzoyl peroxide as an initiator. Polymer–metal complexes were obtained from DMF solutions of polymers with an aqueous solution of metal ions. The polymers and polymer–metal complexes were characterized by elemental analysis and spectral studies. The IR spectra of these complexes suggest that the metals are coordinated through the oxygen of the carbonyl group and the oxygen of the phenolic–OH group. The electronic spectra, electron paramagnetic resonance (EPR) spectra, and magnetic moments of polychelates showed an octahedral and square planar structure for Ni(II) and Cu(II) complexes, respectively. X‐ray diffraction studies revealed that polychelates are highly crystalline. The thermal and electrical properties, catalytic activity, and structure–property relationships are discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2083–2090, 2003     

Kinetics of hydroformylation of 1-decene using homogeneous HRh(CO)(PPh3)3 catalyst: a molecular level approach

The kinetics of hydroformylation of 1-decene using homogenous HRh(CO)(PPh₃)₃ catalyst has been reported in the temperature range of 50–70 °C. The effect of catalyst,P _{H 2},P _CO, and 1-decene concentration on the rate of hydroformylation has been studied. Based on the analysis of initial rate data, a rate equation has been proposed and kinetic parameters evaluated. The activation energy was found to be 11.76 kcal/mol. A molecular level approach to kinetic modelling has also been illustrated. The rate equation derived assuming oxidative addition of H₂ as a rate determining step, has been found to represent the data satisfactorily. The rate parameters for the mechanistic model have been evaluated for the data at 60 °C.NCL Communication No. 5735.     

Aerobic selective oxidation of (hetero)aromatic primary alcohols to aldehydes or carboxylic acids over carbon supported platinum

The synthesis of substituted benzaldehydes, benzoic acids, heterocyclic aromatic aldehydes and acids has been studied via the oxidation of the aromatic alcohols with air under mild pressure (<20 bar) at 100 °C, in the presence of a 1.95 wt.% Pt/C catalyst. The solvent was found to play the most important role in determining the selectivity of the oxidation products. Changing the solvent enabled tuning the reaction either to the aldehyde (pure dioxane), or the carboxylic acid (dioxane/aqueous solution without or with addition of sodium hydroxide). This oxidation method allowed to effectively oxidize many substituted benzylalcohols with various electron-releasing or -attracting groups (NO₂, Me, OMe, Cl, Br, OH, phenyl, …) and heterocyclic alcohols including nitrogen and sulphur atoms (2-thiophenemethanol, 2- and 4-pyridine methanol compounds).     

Synthesis of copolymers of tert‐butyl vinyl ether with maleic and citraconic anhydrides

In the present study, the effects of charge‐transfer complex formation and intramolecular fragmentation (side‐chain lactonization) in radical copolymerization of tert‐butyl vinyl ether (t‐BVE) with anhydrides of maleic (MA) and citraconic (CA) acids and the structure–thermal behavior relationships of the resulting copolymers were examined using the ¹H‐NMR, FTIR, DSC, and TGA analysis methods. It was shown that copolymerization under the chosen conditions proceeded through intramolecular fragmentation with the formation of γ‐lactone units. Side‐chain fragmentation of t‐BVE–MA and t‐BVE–CA copolymers also was confirmed by TGA and DSC analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2455–2463, 2006 2006     

Thermal characterization of n‐alkyl maleate‐styrene‐allyl propionate terpolymers

Thermal characterization of maleic anhydride‐styrene‐allyl propionate (MA‐St‐AP) terpolymer and its ester derivatives named as n‐alkyl maleate and shown as nPr MA‐St‐AP, nBu MA‐St‐AP, nPn MA‐St‐AP, and nBz MA‐St‐AP was carried out. The thermal characterization was performed using thermal analysis techniques such as TGA, DTA, DSC, and TMA. Different results were observed between the original terpolymer and its ester derivatives. Thermal stabilities of the terpolymer and its ester derivatives were compared by using various measurements plotted as TGA, DTA, DSC, and TMA curves. The increase in the alcohols' carbon numbers added to the original terpolymer results in ester derivatives with different thermal stability behavior. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 600–604, 2007