有机硅改性丙烯酸酯共聚乳液合成方法及胶膜性能的研究

用一次投料法、单体乳液滴加法和引发剂滴加法有机硅改性丙烯酸酯共聚乳液，聚合过程、胶粒形态及乳液稳定性的观测结果表明：单体乳液滴加法是合成该类乳液的最佳方法，研究了单体乳液滴加法中有机硅含量与聚合反及胶膜性能的关系，结果表明：有机硅含量在１５％以下时，聚合反应可以顺利进行，胶膜性能不仅依赖于聚合时有机硅单体的总量，而且还依赖于有机硅单体中活性硅氧烷所占的比例。     

Solid phase extraction and analysis of horse urine for aminocaproic acid

Summary A rapid and efficient procedure is described for extraction and determination of aminocaproic acid in horse urine. Urine was extracted by passing through a bonded silica column (Bond-Elut). The adsorbed drug was washed free of endogenous materials before being eluted. The extract was then examined by thin-layer chromatography and HPLC. The purity of the extract was determined by gas chromatography-mass spectrometry.     

Cationic ring-opening polymerization of 3,3-bis（chloromethyl）oxacyclobutane in ionic liquids

Cationic ring-opening polymerization of 3,3-bis(chloromethyl)oxacyclobutane catalyzed by BF_3·OEt_2 was carried out in ionic liquids [bmim]BF_4 and [bmim]PF_6.The influences of BCMO concentration and molar ratio of BCMO/BF_3·OEt_2 on the molecular weights and yield of PBCMO were investigated.The polymerization in ionic liquids proceed to high conversions,although molecular weights are limited,similar to polymerization in organic solvent such as CH_2Cl_2.Follow a viewpoint of green chemistry, we feel ionic liquid [bmim]BF_4 is superior to [bmim]PF_6.Extracting [bmim]PF_6 from the product using organic solvent as extractant limits its advantage as a green reaction media.     

Synthesis of Molecularly Imprinted Polymer Particles by Suspension Polymerization in Silicon Oil

Molecular imprinting is a method to prepare polymers with recognition site of desired and predetermined selectivity1. Molecularly imprinted polymers (MIP) are prepared by copolymerizing functional and cross-linking monomers in the presence of a molecular …     

Development and validation of HPLC methods for enantioseparation of mirtazapine enantiomers at analytical and semipreparative scale using polysaccharide chiral stationary phases

Novel HPLC methods were developed for the analytical and semipreparative resolution of new antidepressant drug mirtazapine enantiomers. At analytical scale, the separation of the mirtazapine enantiomers was investigated using both cellulose and amylose tris(3,5-dimethylphenylcarbamate) (CDMPC and ADMPC) chiral stationary phases under normal-phases and polar organic modes. Good baseline enantioseparation was achieved using cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases under both normal-phases and polar organic modes. Furthermore, the elution order of mirtazapine enantiomic pairs was found reversed by changing the stationary phase from the amylose-based ADMPC–CSPs to its cellulose-based counterpart, CDMPC–CSPs. The validation of the analytical methods including linearity, limit of detection (LOD), limit of quantification (LOQ), recovery and precision, together with the semipreparative resolution of mirtazapine racemate were carried out using cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases and methanol as mobile phase without any basic additives under polar organic mode. At analytical scale, the elution times of both enantiomers were less than 6 min at normal temperature and 1.0 ml/min, with the separation factor () 1.99 and the resolution factor (Rs) 3.56. Then, the analytical methods were scaled up to semipreparative loading to obtain small quantities of both mirtazapine enantiomers. At semipreparative scale, about 16 mg/h enantiomers could be isolated and elution times of both enantiomers were less than 10 min at 2.0 ml/min. To increase the throughput, the technique of boxcar injections was used. One enantiomer ((−)-(R)-mirtazapine) was isolated with purity of >99.9% e.e. and >98.0% yield and another ((+)-(S)-mirtazapine) was isolated with purity of >97.0% e.e. and >99.0% yield. In addition, optical rotation and circular dichroism (CD) spectroscopy of both mirtazapine enantiomers isolated were also investigated.     

Determination of interferon-gamma in Chinese hamster ovary cell culture supernatant by coupled-column liquid chromatography

A robust tandem HPLC method coupling size-exclusion (Shodex Asahipak GS-320HQ) and reversed phase (Vydac 218TP54) columns with ultraviolet detection was developed for quantitative determination of interferon-gamma (IFN-gamma) in Chinese hamster ovary cell culture supernatant. The 2D-HPLC system was linked up by a 6-port 2-position low hold-up volume switch valve. Compared to a commercial ELISA kit for IFN-gamma, the coupled column LC approach was able to detect and quantify soluble IFN-gamma, regardless of the glycoprotein's molecular/conformational variability and sample background. Each LC-LC analysis took 90 minutes inclusive of column regeneration. The relative standard deviation of measurements (n = 5) was less than 3%. The limit of detection (LOD) was determined to be 0.35 microg IFN-gamma.     

Synthesis and Characterization of (βDiketonate)(7-norbornadienyl acetate)Copper(l) Complexes,Single-Crystal Structure of (hfac)Cu(7-AcO-NBD)

Copper(I) complexes of general formula (β-diketonate)Cu(7-AcO-NBD), where 7-AcO-NBD = 7-norbornadienyl acetate and β-diketonate = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate (1), 1,1,1-trifluoro-2,4-pentanedionate (2), 2,4-pentanedionate (3), 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate (4), 4,4,4-trifluoro-1-phenyl-1,3-butanedionate (5), were prepared from reactions of CuCl with Na(β-diketonate) in the presence of 7-AcO-NBD. AH compounds were characterized by elemental analyses, ¹H, ¹³C, ¹⁹F NMR and IR spectra. Single-crystal strucutre of compound 1 was determined by X-ray diffraction analysis that showed a mononuclear copper species with coordination of a chelating β-diketonate ligand through two oxygen atoms and the 7-AcO-NBD through its C? C double bond and an oxygen atom in the solid state. For compound 1, the crystal data are: triclinic, space group $ {\rm P}\bar 1 $, a= 5.4519(14) Å, b= 11.852(3) Å, c= 13.304(3) Å, α = 74.721(20)° β = 80.220(20)°, γ= 76.848(19)°, Z = 2, R_F = 0.060 and R_w = 0.064. Hot-wall chemical vapor deposition experiments revealed that compound 1 is suitable as a precursor for deposition of copper films in the temperature range 170–260 °C.     

Solvent effect in cis-1,4 polymerization of 1,3-butadiene by a catalyst based on neodymium

In this work a laboratory polymerization scale process was studied for the production of polybutadiene with high content of cis-1,4 repeating units. A Ziegler-Natta catalytic system based on neodymium versatate (catalyst), diisobutylaluminium hydride (cocatalyst) and tert-butyl chloride (chlorinating agent) was used. The influence of solvent nature (pure grade) and possible contaminants (electron donors) in a recovered solvent from a butadiene-styrene anionic polymerization industrial plant on the stereoselectivity and catalytic activity, molecular weight and molecular weight distribution of the resultant polybutadienes was studied. The polymers were characterized by infrared spectroscopy and size exclusion chromatography. Polybutadienes with cis-1,4 units content in the range of 99-98% were produced. The polymers weight-average molecular weight, , varied from 2.23 × 10⁵ to 4.47 × 10⁵ and the molecular weight distribution, MWD, from 3.1 to 5.1.     

Preconcentration and Determination of Chromium Species Using Octadecyl Silica Membrane Disks and Flame Atomic Absorption Spectrometry

A novel and selective method for the fast determination of trace amounts of chromium species in water samples has been developed. The procedure is based on the selective formation of chromium diethyldithiocarbamate complexes at different pH in the presence of Mn(II) as an enhancement agent of chromium signals followed by elution with organic eluents and determination by atomic flame absorption spectrometry. The maximum capacity of the employed disks was found to be (396±3) µg and (376±2) µg for Cr(III) and Cr(VI), respectively. The detection limit of the proposed method is 49 and 43 ng·L^?1 for Cr(III) and Cr(VI), respectively. The proposed method was successfully applied for determination of chromium species Cr(III) and Cr(VI) in different water samples.     

Novel pyridinium salts as cationic thermal and photoinitiators and their photosensitization properties

Novel pyridinium salts [N‐(α‐phenylbenzyl)‐, N‐(1‐naphthylmethyl)‐, or N‐cinnamyl p‐ or o‐cyanopyridinium hexafluoroantimonates] were synthesized by the reaction of p‐ or o‐cyanopyridine and the corresponding bromides followed by anion exchange with KSbF₆. These pyridinium salts polymerized epoxy monomers at lower temperatures than previously reported for N‐benzyl‐2‐cyanopyridinium hexafluoroantimonate. The o‐substituted pyridinium salts showed higher activity than the p‐substituted ones, and the crosslinked epoxy polymers cured with these initiators showed higher glass‐transition temperatures. These pyridinium salts photoinitiated radical polymerization as well as cationic polymerization. The photopolymerization was accelerated by the addition of aromatic ketones as photosensitizers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1037–1046, 2002