A novel photo-initiated approach for preparing aluminum diethylphosphinate under atmospheric pressure

A novel preparation of aluminum diethylphosphinate（AlPi） was carried out with free-radical addition reaction by means of UV-irradiation under atmospheric pressure.A solution of sodium hypophosphite was treated with ethylene and irradiated with ultraviolet light in the presence of an amount of photoinitiator effective to initiate the free-radical reaction between the hypophosphite anion and the double bond of the ethylene molecule.The ethylene was micro-bubbled into the reaction mixture with the addition of the photoinitiator,and the gas-liquid contact surface and the photoinitiator concentration in the gas-liquid interface were increased largely.The yield of the final product could be improved to about 96%.The contents of P,Al in samples were detected by ICP,and the molecular structure of the samples was confirmed by ³¹P NMR,¹H NMR and FTIR spectroscopic analysis.Thermal stability of the final products was investigated in detail by TG-DTA.     

Enzymatic Synthesis of a CCK-8 Tripeptide Fragment

A process for the synthesis of CCK-8 tripeptide H-Gly-Trp-Met-OH catalyzed by immobilized enzyme was reported. Enzymes were used for the formation of peptide bonds and the removal of protecting group. Starting with phenylacetyl (PhAc) glycin, N-protected dipeptide PhAc-Gly-Trp-OMe was obtained by coupling PhAc-protected glycine carboxamidomethyl ester (OCam) with Trp-OMe catalyzed by immobilized papain in buffered ethyl acetate. Then the condensation between PhAc-Gly-Trp-OMe and Met-OEtoHC1 was carried out by immobilized α-chymotrypsin catalysis in solvent free system. Basic hydrolysis was followed getting PhAc-Gly-Trp-Met-OH. The PhAc-group was removed with penicillin G amidase and H-Gly-Trp-Met-OH was obtained in an overall yield of 43.9%. The reaction conversion of tripeptide in solvent free system was strongly affected by the system of basic salts added. The influence of the support materials used to deposit enzymes and structures of acyl donor and nucleophile on the reaction was also investigated.     

PRELIMINARY STUDIES ON A LECTIN ON THE SURFACE OF ADIPOCYTES

A lectin-like component on the surface of porcine adipoeytes was identified, chiefly by means of the cell adhesion and helnagglutination assays. This component, named porcine adipocyte lectin (PAL), was isolated with Triton X-100 solubilization followed by affinity chromatography. By SDS-polyacrylamide gel electrophoresis, two hands of PAL stained with Coomassie blue were revealed with the apparent molecular weights of 112,000 and 89,000. Moreover, the glycoprotein nature of PAL, was demonstrated by periodic-Schiff reagent staining. PAL was able to recognize maltose, mannose and mammal and glycoproteins with analogous sugar structure in the presence of Ca. By the finding that adipocytes in suspension could be aggregated by adding PAL, the hypothesis was advanced that PAL may be involved in the recognition and adhesion of adipocytes in vivo     

Effect of tetrabutylammonium bromide on enzymatic polymerization of phenol catalyzed by horseradish peroxidase

In this article tetrabutylammonium bromide （TBAB） was first added in buffer to compose a convenient and environmentally friendly system, and enzymatic polymerization of phenol catalyzed by horseradish peroxidase （HRP） could proceed efficiently in this system. When TBAB was added, the most conversion of phenol could reach 99.1%. The phenol polymer was considered to consist of a mixture of phenylene （Ph） and oxyphenylene （Ox） units by IR analysis, and the ratio of phenylene to oxyphenylene units （Ph/Ox） was measured by titration. Moreover, the effects of the dosage of horseradish peroxidase （HRP） and pH value on the conversion of phenol were investigated. The reaction performed very effectively in this novel system when the addition of HRP was only 0.2 mg. In all cases, the weight-average molecular weight calculated by GPC-SLS was in a range from 12000 Da to 30000 Da. The phenol polymer prepared in the present research possessed good thermal stability shown by TG analysis.     

Electrochemical Oxidation of Chlorimuron-ethyl on Ti/SnO2-Sb2O5/PbO2 Anode for Waste Water Treatment

<正>The electrochemical oxidation of chlorimuron-ethyl on Ti/SnO_2-Sb_2O_5/PbO_2 electrode was studied by cyclic voltammetry. The electrochemical behaviour of the electrode in a sodium sulfate solution and in the mixture solution of sodium sulfate and chlorimuron-ethyl was studied.The experimental results of cyclic voltammetry show that the acidic medium was suitable for the efficient electrochemical oxidation of chlorimuron-ethyl.Some electro-generated reagent was formed in the electrolysis process and chlorimuron-ethyl could be oxidized by the electro-generated reagent.A Ti/SnO_2-Sb_2O_5/PbO_2 electrode was used as the anode and the electrolysis experiment was carried out under the optimized conditions.The electrolysis process was monitored by UV-Vis spectrometry and high performance liquid chromatography(HPLC),and the chemical oxygen demand(COD) was determined by the potassium dichromate method.The mechanism of chlorimuron-ethyl to be oxided was studied primarily by the cyclic voltammetry and UV-Vis spectrometry.The results of electrolysis experiment demonstrate the possibility of the electrode to be used as an anode for the electrochemical treatment of chlorimuron-ethyl contained in waste water.     

PREPARATION OF POLY（METHYL METHACRYLATE）/LAYERED DOUBLE HYDROXIDES NANOCOMPOSITES via in situ SOLUTION POLYMERIZATION

An exfoliated layered double hydroxides/poly(methyl methacrylate)(LDHs/PMMA)nanocomposite was prepared by in situ solution polymerization of methyl methacrylate(MMA)in the presence of 4-vinylbenzenesulfonate intercalated LDHs(MgAl-VBS LDHs).MgAl-VBS LDHs was prepared by the ion exchange method,and the structure and composition of the MgA1-VBS LDHs were determined by X-ray diffraction(XRD),infrared spectroscopy and elemental analysis.XRD and transmission electron microscopy(TEM)were employed to examine the structure of LDHs/PMMA nanocomposite.It was indicated that the LDHs layers were well exfoliated and dispersed in the PMMA matrix.The grafting of PMMA onto LDHs was confirmed by the extraction result and the weight fraction of grafted PMMA increased as the weight fraction of LDHs in the nanocomposites increased.     

Optical and mechanical properties of polyurethane/surface-modified nanocrystalline cellulose composites

in order to improve the optical and mechanical performances of waterborne polyurethane （WPU）, nanocrystalline cellulose （NCC）/WPU composites were synthesized in this study. NCC （prepared by acid hydrolysis of cotton fiber） was modified by （3-aminopropyl）triethoxysilane （APTES） to enhance its compatibility with WPU, and the surface-modified NCC was characterized by grafting ratio, crystallinity and contact angle （CA）. NCC/WPU composites were examined by scanning electron microscopy （SEM）, X-ray powder diffraction （XRD） and thermogravimetric analysis （TG）. The anti-yellowing property, specular gloss, pencil hardness, and abrasion resistance of NCC/WPU composites were investigated by the methods of Chinese National Standards GB/T 23999-2009, GB/T 9754-2007, GB/T 6739-2006 and GB/T 1768-2006, respectively. The results showed that the grafting ratio of NCC modified by 6% APTES was 36.01% and the crystallinity of modified NCC was decreased with the enhancement of APTES. CA of the modified NCC was decreased by 28.8% and the nanoparticles were homogeneously dispersed in the WPU matrix. The XRD patterns of the NCC/WPU composites were relatively steady, while the thermal stability of the composites was enhanced by 6.7% with 1.0 wt% modified NCC. Modified NCC affected the specular gloss of NCC/WPU composites more obviously than the anti-yellowing property. The pencil hardness of NCC/WPU composites was increased from 2H to 4H by addition of NCC and the abrasion resistance of the composites was enhanced significantly. In general, NCC/WPU composites showed significant improvements in the optical and mechanical performances.     

Flow—injection Chemiluminescence Determination of Reserpine in Medicine and Biological Fluids with Controlled—Reagent—Release Technology

A sensitive and rapid chemiluminescence(CL) flow injection with controlled-reagent-release technology for the determination of reserpine was proposed.The Cl reagents,luminol and dichromate,uses in this sensor,were all immobilized on anion-exchange resin.Through injection of 100μl of water,the reagents on the anion-ex-change resin column were eluted and in the presence of reserpine ,the CL intensity was decreased,by which reserpine could be sensed.Reserpine was quantified by measuring the decrement of CL intensity,which was observed linear with the logrithm of reserpine concentration in the rage of 1.0-500.0ng/mL,and the limit of detection was 0.4ng/mL(3σ)with a relative standard deviation of less than 3.0?The proposed procedure was applied in the assay of reserpine in pharmaceutical preparation and biological fhuids without any pre-treatment process and with sampling frequencies of 72 times per hour.     

Morphological studies on Sn-O coordination driving self-assembly of well-defined organotin-containing block copolymers

A tin-oxygen coordination driving self-assembly was developed in the block copolymers containing organotin, which were prepared by the radical addition-fraction transfer（RAFT） method and characterized by the gel-permeation chromatography（GPC） and 1H-NMR. And the self-assemblies of these block copolymers with various chain length ratios in the different concentrations in CHCl3 were stable according to the results of DLS and TEM. Additionally, it was also given an insight investigation on the regulation of self-assembly of the block copolymers by adding dibutyltin dichloride and a possible mechanism was proposed.     

The Mobility of Threaded α-Cyclodextrins in PR Copolymer and Its Influences on Mechanical Properties

The methylated polyrotaxane(Me PR) copolymer was prepared via the methylation of hydroxyl of threaded α-cyclodextrin(α-CDs) in polyrotaxane(PR) copolymer by CH_3I/Na H. Its structure was characterized by GPC, IR and NMR. The WXRD and TGA measurements showed the destruction of channel-like crystalline structure in Me PR copolymer. The sliding of threaded α-CDs along PEG axis in PR and Me PR copolymers was demonstrated by their dielectric spectra that also evidenced the presence of rotating of threaded α-CDs around PEG axis in Me PR copolymer. The frequent and vigorous molecular mobility in Me PR and PR copolymers was also verified by dynamic mechanical analysis(DMA) and rheological measurement, which was possibly assigned to the sliding and rotating of threaded α-CDs. DMA and rheological results showed that the mobility of α-CDs could simultaneously strengthen and toughen PR copolymer proved by stress-stain curves. In this paper, we report the CD mobility in PR and Me PR copolymers. The macroscopic behaviors of PR copolymer, such as mechanical properties in solid state, were also found to be benefited from CD mobility.     

Characterization of TiO2 Loaded on Activated Carbon Fibers and Its Photocatalytic Reactivity

In this paper, TiO2 loaded on activated carbon fibers （ACF） was prepared by a coating treatment, followed by calcination at different temperatures in air atmosphere. The photocatalyst developed was characterized by SEM, XRD, XPS and UV-Vis adsorption spectroscopy. It was observed from SEM images that TiO2 loaded on ACF was in the form of small clusters with nanometer size. As confirmed by XRD and XPS determinations, the crystalline pattern of immobilized TiO2 was still anatase-form after calcination, and the micrographic structure and surface properties of ACF have not been damaged by the deposition process and calcination at different temperatures. Photocatalytic degradation of methylene blue （MB） in aqueous .solution was investigated using TiOE/ACF as photocatalyst. The comparison of photolysis, absorption and photocatalysis was carded out. The results indicated that the photocatalysis process of combined photocatalyst showed much higher degradation rate than that of photolysis and absorption processes. In addition, the possibility of cyclic usage of the photocatalyst was also confirmed.     

Introduction to “Chemical Journal of Chinese Universities”

＂Chemical Journal of Chinese Universities＂（Chinese Edition） is a comprehensive academic journal in the field of chemistry sponsored by Jilin University and Nankai University mandated by the Educational Ministry of China and published by the Higher Education Press in China. Its original journal name was ＂Natural Science Journal of Chinese Universities＂（Chemistry and Chemical Engineering Edition） started in 1964, and was changed into the present journal name in 1980. Since 1985, the journal has been published monthly.     

酸碱处理后纳米微晶纤维素的热行为分析

Nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) by acid hydrolysis. It was observed that the diameter of NCC particles mainly distributed over 30-50nm by transmission electron microscope (TEM) . The crystal form and degree of crystallinity were detected by X-Ray diffraction. The results showed that NCC and MCC have the same crystal form of cellulose I, and that the reactions mainly occurred in the amorphous region of MCC during the acid hydrolysis process. The thermal behavior of NCC in different pH conditions was characterized by differential scanning calorimetry (DSC) . The consequences indicate that the thermal stability of NCC distinctly decreased by contrast with the thermal stability of MCC, and that the thermal stability of NCCs in alkali conditions was higher than that of NCCs in acid conditions. The specific surface area distinctly increased with sharp decreasing of the particle size of NCC. This induced the end carbons and active groups of surface of NCC to increase sharply, therefore caused the thermal stability of NCC to distinctly abate. That NCC has very strong adsorption affinity is the cause of the obvious difference of thermal behavior of NCC in different pH. In acid conditions the surface of NCC adsorbed a great lot of H^ , which induced the cellulose chains of surface of NCC to decompose at low temperature catalyzed by H^ . When adding sodium hydroxide solution, on one hand the H^ of surface of NCC was neutralized; on the other hand, the cellulose chains of low molecular weight were dissolved in sodium hydroxide solution and the defects of surface of NCC rearranged and stable structure formed. These factors improved the thermal stability of NCC in alkali conditions.     

Studies on the Total Synthesis of Hainanolide (VII) - Analysis of the Relative Stereochemistry of key Intermediate 2

The natural product, hainanolide 1, also under the name harringtonolide2 demonstrated antitumor and antiviral activities in preliminary test. Its structure was determined by X-ray diffraction. The total synthesis of 1 was reported recently by Mander3. A different scheme of its synthesis has been studied in our laboratory4. Here the determination of the stereochemical structure of the key intermediate 2 in the synthesis was reported. HMBC and HMQC spectra identified the skeleton and H,…     

PREPARATION OF NANOMETER TiO2 ORGANIC SOLUTION —EFFECT OF ORGANIC SILOXANE ON SOL PROPERTIES*

A homogeneous longtime stabilized transparent nanometer TiO2 organic solution was obtained by means of the simultaneous hydrolysis and co-polycodensation of tetrabutyltitanate (TBT) and methacryloxypropyltrimethoxysilane (MAPTMS) by the sol-gel process. The particle size of nanometer titanium dioxide was controlled by use of bifunctional silanes, such as diphenyldimethoxysilane (DPDMS), diphenyldiethoxysilane (DPDES) and dimethyldiethoxysilane (DMDES). The effect of TiO2 content in the solution on the refractive index of system was discussed in detail. The result shows that the refractive index of solution increases linearly with TiO2 content. The refractive index of the three hybrid nanometer materials attained 1.6053, 1.5846 and 1.5346, respectively. The size of nanometer particles was characterized by TEM and the particle diameter thus obtained is in the range of 20-90 nm. FT-IR spectra of the materials show that the TiO-Si bond is formed.     

STRUCTURE OF PLASMA-POLYMERIZED OCTAFLUOROCYCLOBUTANE

Plasma-polymerization of octafluorocyclobutane was carried out in a capacitively coupled tubu-lar reactor with external electrodes. The number-average molecular weight, melting temperature,decomposition temperature and solubility in te trafluorodibromoethane of the products was mea-sured and the polymer structure was characterized by ESR. IR and ~(1)9F-NMR methods. The experi-mental results show the absence of the highly crosslinked structure but a fluorine-deficient structurecaused by free-radicals, carbonyl groups. double bonds and multicage-like segments in the polymer.     

Decomposition of Organic Compounds in Coke Plant Wastewater by Ultrasonic Irradiation and Its Combined Process

The paper deals with the degradation of the organic compounds in the coke plant wastewater by the com-bined process of ultrasonic irradiation and activated sludge. The influence factors of the ultrasonic degrada-tion effect such as air atmosphere, initial concentration, ultrasonic power density and the category and con-sumption of catalyst were investigated. A water quality model was used to explain the degradation of differ-ent kinds of organic compounds in the coke plant wastewater by ultrasonic irradiation. After the wastewater was treated by the combined process of ultrasonic irradiation and activated sludge, the COD degradation effi-ciency was 95.74%, which is 63.49% higher than that by the process of activated sludge alone.     

Degradation of sulfadiazine antibiotics by water falling film dielectric barrier discharge

A new water falling film dielectric barrier discharge was applied to the degradation of sulfadiazine in the aqueous solution. The various parameters that affect the degradation of sulfadiazine and the proposed evolutionary process were investigated. The results indicated that the inner concentrations of 10 mg/L sulfadiazine can be all removed within 30 min. The optimum pH value was 9.10 and both strong acidic and alkaline solution conditions were not suitable for the degradation. The degradation of sulfadiazine can be enhanced by the addition of hydrogen radical scavengers, but be inhibited by adding hydroxyl radical scavengers. The water falling film dielectric barrier discharge was rather ineffective in mineralization, because of the intermediates were recalcitrant to be degraded. The existence of Fe2+and CCl4 in the liquid phase can promote the degradation and mineralization of sulfadiazine. It was found that the degradation of SDZ was enhanced by CCl4 was mainly because of the increase of OH due to the reaction of CCl4 with H that reduce the chances of their recombination with OH. Based on the 8 intermediate products identified by LC–MS, the proposed evolution of the degradation process was investigated.     

硅酸盐修饰Ni/海泡石催化剂的制备

Under the hydrothermal condition, the surface of sepiolite was restored with silicate and Ni was precipitated on the restored sepiolite by precipitating-reducing method. The surface of the samples was characterized by SEM, BET and XRD. The catalytic ability was examined by hydrogenation of toluene in gas phase over the silicate restored Ni/sepiolite catalyst. The experimental results show that distribution of Ni over the surface of the sample was even with bare aggregation and can be controlled, the ability of anti-aging of this catalyst was about ten times higher than that prepared by impregnation method at the same reactive condition.     

EXTRACTION CHEMISTRY OF RARE EARTHS BY MONO-ALKYL ISOPROPYLPHOSPHONATES

The influence of chemical structure of ester alkyl group of mono-alkyl isopropylphosphonates on the extraction behaviours of rare earth has been studied. The mono-alkyl isopropylphosphonate bearing β-substituted ester alkyl group shows high K_(ex) value, which is evidently depressed, usually in two orders of magnitude, by introducing a branch chain on the α-position of the ester alkyl group. The steric effect of ligand is usually enhanced due to the characteristic lanthanide contraction.z2The extraction chemistry of rare earths by mono-amylnonyl isopropylphosphonates (MANPP) was studied in detail The thermodynamic function was estimated and the "tetrad effect" between K_(ex) value or △G value and atomic number was observed. In addition, the composition and structure of the coordinated compound was studied. As demonstrated by the experimental data, the extractive separation of Sm and Nd by MANPP in chloride solution was better than that in nitrate system.