高稳定性硅基杂化纤维素衍生物手性固定相的制备及其色谱拆分性能

合成了含少量3-(三乙氧基硅)丙基氨基甲酸酯的纤维素3,5-二甲基苯基氨基甲酸酯衍生物(CDMPC),并采用1,2-二(三乙氧基硅基)乙烷(BTSE)为偶联剂,通过溶胶-凝胶法成功制备得到新型硅基杂化手性固定相。该固定相的CDMPC含量达60%,在含有10%氯仿的流动相中保持良好的手性识别性能和机械强度。使用其拆分了多种手性化合物,拆分效果优于商品柱Chiralpak IB,其中对2,2,2-三氟-1-(9-蒽基)乙醇和反式二苯乙烯氧化物对映体的分离选择性分别达到2.99和2.48,表明该类硅基杂化类手性固定相在制备色谱领域中有潜在应用前景。     

应用高压液相色谱法分析苏脲1号

新型的抗蜕皮杀虫剂卤代苯甲酰基取代脲类,国内外研究和应用的主要品种有PH6038(2,6-二氯苯甲酰基4-氯苯基脲)、PH6040(2,6-二氟苯甲酰基4-氯苯基脲)和苏脲1号(2-氯苯甲酰基4-氯苯基脲)。上述三种取代脲的分析方法已见报道的有PH6038的核磁共振法、气相色谱法、比色法,PH6040的     

β-环糊精衍生物作为流动相添加剂在纤维素三苯基氨基甲酸酯手性柱上的应用

以微晶纤维素和苯基异氰酸酯为原料合成了纤维素三苯基氨基甲酸酯,涂敷于氨丙基硅烷化硅胶上制成手性固定相。并以β-环糊精衍生物为手性流动相添加剂在手性柱上进行对映体的拆分。结果表明,当使用手性固定相和含有手性添加剂的流动相分离手性化合物时存在手性两相协同作用,其中以2,3,6-三甲基-β-环糊精(TM-β-CD)为流动相添加剂时的效果最好。     

几个含噻二唑环芳甲酰基脲的合成及生物活性

通过2-氨基-5-(3-吡啶基)-1,3,4-噻二唑与取代苯甲酰基异氰酸酯反应,得到相应的芳甲酰基脲:N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-氯苯甲酰基)脲(Ⅲa)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-溴苯甲酰基)脲(Ⅲb)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(4-溴苯甲酰基)脲(Ⅲc)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-甲基苯甲酰基)脲(Ⅲd)和N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(4-三氟甲基苯甲酰基)脲(Ⅲe),收率分别为69.5%、67.2%、73.1%、66.8%和71.6%.产物的结构经红外光谱、核磁共振氢谱、质谱与元素分析表征.并对目标化合物进行了植物生长调节活性测试,初步的测试结果表明,目标化合物在10 mg/L表现出一定程度的生长素活性和较好的细胞分裂素活性,其中Ⅲc和Ⅲe的细胞分裂素活性超过40%.     

2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖基异硫氰酸酯的合成与应用

以α D 葡萄糖为原料经过乙酰化、溴化、硫氰酸化三步反应合成了 2, 3, 4, 6 四 O 乙酰基 β D 吡喃葡萄糖基异硫氰酸酯。用NMR对其进行了表征。考察了相转移催化剂种类及用量、反应时间、溶剂对反应的影响。得出最佳反应条件为:以苯做溶剂,物料摩尔比为n(2, 3, 4, 6 四 O 乙酰基 α D 吡喃溴代葡萄糖)∶n(硫氰酸钾 )∶n(三乙基苄基氯化铵) =1∶2∶1,反应时间为 14h。把它用作柱前衍生试剂拆分异构体,测定了对映体过量 (ee)值,均得到了满意的结果。     

5个含噻二唑环芳甲酰基脲的合成及生物活性

通过2-氨基-5-(3-吡啶基)-1,3,4-噻二唑与取代苯甲酰基异氰酸酯反应,得到相应的芳甲酰基脲:N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-氯苯甲酰基)脲(Ⅲa)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-溴苯甲酰基)脲(Ⅲb)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(4-溴苯甲酰基)脲(Ⅲc)、N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(2-甲基苯甲酰基)脲(Ⅲd)和N-[5-(3-吡啶基)-1,3,4-噻二唑-2-基]-N′-(4-三氟甲基苯甲酰基)脲(Ⅲe),收率分别为69.5%、67.2%、73.1%、66.8%和71.6%。产物的结构经红外光谱、核磁共振氢谱、质谱与元素分析表征。并对目标化合物进行了植物生长调节活性测试,初步的测试结果表明,目标化合物在10mg/L表现出一定程度的生长素活性和较好的细胞分裂素活性,其中Ⅲc和Ⅲe的细胞分裂素活性超过40%。     

手性OJ柱填料的制备及性能测定

以微晶纤维素为原料合成纤维素三 (4 -甲基 )苯甲酸酯 (p-MBC) ,并涂在大孔硅胶上制成 HPLC手性填料且高压填 (2 5 cm× 0 .46 cm)分析柱并测其性能 ;通过改变流动相配比和流速 ,找出此柱的最佳拆分条件。三种药物对映体在自制 OJ柱上得到较好的拆分。     

高效液相色谱法对β-羟基酮类衍生物的手性拆分

采用高效液相色谱法,以Chiralpak IA柱[直链淀粉-三(3,5-二甲基苯基氨基甲酸酯)]为手性固定相对新合成的7个含4-取代苯基4-羟基-丁-2-酮类衍生物对映体进行了手性拆分。通过考察不同流动相体系,优化了对映体色谱分离条件,同时初步探讨了在手性识别过程中流动相组成和极性对于对映体拆分和保留的影响。     

纤维素-三(3,5-二甲基苯基氨基甲酸酯)对烯唑醇对映体的直接拆分

制备了纤维素-三(3，5-二甲基苯基氨基甲酸酯)手性固定相(CDMPC)，以正己烷为流动相，添加异丙醇为改性剂，在高效液相色谱上实现了对烯唑醇光学异构体的直接拆分，探讨了改性剂的含量及色谱柱长对拆分效果的影响，从而优化了拆分条件。试验结果显示，流动相中异丙醇含量的减少有利于对映体的拆分，但保留增强；长色谱柱也有利于对映体的分离。使用两色谱柱串连，当流动相中正己烷与异丙醇的比例为95：5时可达到最佳分离效果，分离因子为1．17。     

手性药物及基其薄层色谱拆分

手性药物的活性和药效很大程度取决于它的结构，往往一种对映体有药效面而另一种对映体无药效甚至有毒副作用，近年来，色谱法分离对映体已成为重要的和迅速发展的研究领域。本文对薄导色谱法在拆发对映体方面的应用情况作一概述，包括纤维素及其衍生物，β－－环糊精及其衍生物，铜和光学活性配位络合物及电转移络合物等手性固定相拆分法，手性流行相添加剂的拆分法和某些药物的活性和它们的构象之间关系也被叙述。     

Photopyroelectric Spectroscopic Studies of ZnO-MnO(2)-Co(3)O(4)-V(2)O(5) Ceramics

Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV for 0.3 mol% V(2)O(5) at a sintering temperature of 1025 °C as determined from the plot (ρhυ)(2)versushυ. With a further increase in V(2)O(5), the value of E(g) was found to be 2.59 eV. Steepness factor 'σ(A)' and 'σ(B)', which characterize the slope of exponential optical absorption, is discussed with reference to the variation of E(g). XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively.     

以( )-脱氢枞胺为原料合成( )-弥罗松酚

报道了以(+)-脱氢枞胺为起始原料,通过两条路线合成生物活性的二萜化合物(+)-弥罗松酚。路线(1):(+)-脱氢枞胺在羟氨-O-磺酸和氢氧化钠作用下还原脱氨生成脱氢松香烷,再经Friedele-Crafts乙酰化、BaeyerVilliger氧化、水解生成(+)-弥罗松酚,总产率29.5%。路线(2):(+)-脱氢枞胺还原脱氨,然后与过氧化邻苯二甲酰反应得到(+)-弥罗松酚,总产率31.9%。     

Rheological behavior of blends of poly(methyl methacrylate) (PMMA) and poly(acrylonitrile-stat-styrene)-graft-polybutadiene (ABS)

The rheological behavior of blends of poly(methyl methacrylate) (PMMA) and poly(acrylonitrile-stat-styrene)-graft-polybutadiene (ABS) was investigated using a cone-and-plate rheometer. The rheological properties measured were shear stress (σ₁₂), viscosity (η), and first normal stress difference (N₁) as functions of shear rate (\documentclass{article}\pagestyle{empty}\begin{document}$ \dot \gamma$ \end{document}) in steady shearing flow, and storage modulus (G′) and loss modulus (G″) as functions of frequency (ω) in oscillatory shearing flow. It has been found that the rheological behavior of blends of ABS and PMMA was very similar to that of blends of poly(styrene-stat-acrylonitrile) (SAN) and PMMA, in that N₁ in logarithmic plots of N₁ versus σ₁₂, and G′ in logarithmic plots of G′ versus G″, vary regularly with blend composition. This has led us to conclude that the rubber particles that are grafted on an SAN resinous matrix in ABS resin plays only a minor role in influencing the compatibility of ABS/PMMA blends, and that the SAN chains attached to the surface of rubber particles, and the SAN matrix phase, play a major role in compatibilizing ABS resin with PMMA.     

Biological Properties of IRIM, the Iridium(III) Analogue of (Imidazolium (Bisimidazole) Tetrachlororuthenate) (ICR)

Some biological aspects of the new complex imidazolium bisimidazole tetrachloro iridate(III)-IRIM- the iridium(III) analogue of ICR, were considered. More in detail the conformational effects produced by IRIM on DNA and the cytotoxic properties of IRIM on some selected human cell lines were measured. Dialysis experiments and DNA thermal denaturation studies are suggestive of poor binding of IRIM to DNA; formation of interstrand crosslinks is not observed. In any case CD measurements suggest that addition of increasing amounts of IRIM to calf thymus DNA results into significant spectral changes, that are diagnostic of a direct interaction with DNA. A number of experiments carried out on the A2780 human ovarian carcinoma, B16 murine melanoma, MCF7 and TS mammary adenocarcinoma tumor cell lines strongly point out that IRIM does not exhibit significant growth inhibition effects within the concentration range 10(-4)-10(-6) M. It is suggested that the lower biological effects of IRIM compared to ICR are a consequence of the larger kinetic inertness of the iridium(III) center with respect to ruthenium(III).     

Thermal studies of blends of poly(phenylene sulfide) (PPS) with poly(phenylene sulfide sulfone) (PPSS) and with poly(phenylene sulfide ether) (PPSE)

The miscibilities of poly(phenylene) sulfide/poly(phenylene sulfide sulfone) (PPS/PPSS) and poly(phenylene) sulfide/poly(phenylene sulfide ether) (PPS/PPSE) blends were invesigated in terms of shifts of glass transition temperatures T_g of pure PPS, PPSS, a dn PPSE. The crystallization kinetics of PPS/PPSS blends was also studied as a function of molar composition. The PPS/PPSS and PPS/PPSE blends are respectively partially and fully miscible. PPSE shows a plasticizing effect on PPS as does PPS on PPSS, which necessarily improves te processibility in the respective systems. We can control T_g and melting temperature T_m of PPS by varying amounts of PPSE in blends. The melt crystallization temperature T_mc of PPS/PPSE blends was higher than that of the PPSE homopolymer. Therefore, these blends require shorter cycle times in processing than pure PPSE. The overall rate of crystallization for PPS/PPSS blends follows the Avrami equation with an exponent ?2. The maximal rate of crystallization for PPS/PPSS blends occurs at a temperatre higher by 10°C than that for PPS, while the crystallization half time t_1/2 is 4 times shorter. In the cold crystallization range, crystal growth rates increase and Avrami exponents decrease significantly as the temperature increases.     

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

The addition of side groups to improve the photooxidative stability of polymers used in polymer-based light-emitting diodes (LEDs) is explored. Infrared spectroscopy and computational chemistry techniques are used to study the effects of chemical substitution of the reactive vinylene moiety in poly(phenylene vinylene) (PPV). The bond order of the vinylene group in small oligomers is calculated using semiempirical techniques to assess the improvement in stability toward oxidants such as singlet oxygen. We find that PPV dimers allow relative comparisons across a range of possible substitutions. Experimental results correlate well with these calculations. The addition of electron-withdrawing substituents, such as nitrile groups, to the vinylene moiety is found to be particularly effective in reducing the reactivity of alkoxy-substituted PPV toward singlet oxygen. The photooxidative stability of a poly(phenylene acetylene) (PPA) derivative is also studied. It appears that this family of polymers is more stable toward photooxidation than are its PPV analogs. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2451–2458, 1998     

Chemical cross-linking of conducting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) using poly(ethylene oxide) (PEO)

Hybrid films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) were prepared with different molecular weights of poly(ethylene oxide) (PEO). The cross-linking reaction between PEO and PEDOT:PSS was performed at high temperature and confirmed by using differential scanning calorimeter (DSC), contact angle measurement, and solid-state ¹H NMR. The effect of chemical reaction on the conductivity and morphology of these hybrid films was studied by using 4-point probe and atomic force microscope (AFM), respectively. As-spun PEO/PEDOT:PSS films have lower electric conductivity due to the addition of nonconductive PEO, and exhibits no molecular weight dependence on conductivity. After chemical cross-linking reaction at high temperature, only PEDOT:PSS films with lowest molecular weight PEO additives show enhanced conductivity with increasing reaction time. AFM result indicates that the heat-treated PEO/PEDOT:PSS hybrid films show grain-like morphology compared to ethylene glycol treated PEDOT:PSS films which shows continuous PEDOT domain. In the present work we demonstrate that the cross-linking reaction can be used to improve the wet stability of PEDOT:PSS nanofiber, showing good water resistance and excellent dimensional stability.     

Photo-Initiated Lamination of Polyethylene (PE) and Poly(ethylene terephthalate) (PET)

Besides plasma-based processes, photo-initiated surface modifications have an interesting potential for adhesion promotion. This is of special interest with applications ranging from classical finishing to composites. Photo-chemical processes using continuous UV sources — monochromatic as well as broad band — are based on radical activation and ensuing reaction with the atmosphere. Achievable effects are addition of atoms — e.g., introduction of oxygen (photo-oxidation) resulting in increased surface energy — or grafting of functional groups. Both have certain potentials for adhesion promotion in a physico-chemical way. Based on the fundamental scheme of these processes — i.e., a photon-initiated radical reaction at the substrate-atmosphere interface — a direct 'inter-linking' of coating polymer and substrate is presented in this paper. The principal idea is to apply a thin layer of coating polymer on the substrate and irradiate this composite system at certain UV wavelengths. Given a low absorption of the radiation by the thin coating and — at the same time — a high absorption by the substrate, the radiation will penetrate the coating layer and generate radicals at the interface, which will induce cross-linking between the coating polymer and substrate. It is shown that for the example of laminates of polyethylene (PE) film on fabrics made of poly(ethylene terephthalate) (PET), extremely high adhesion strenghths are achieved without any use of additional adhesion promoters.     

Finite strain behavior of poly(ethylene terephthalate) (PET) and poly(ethylene terephthalate)-glycol (PETG)

Uniaxial and plane strain compression experiments are conducted on amorphous poly(ethylene terephthalate) (PET) and poly(ethylene terephthalate)-glycol (PETG) over a wide range of temperatures (25-110 °C) and strain rates (.005-1.0 s⁻¹). The stress-strain behavior of each material is presented and the results for the two materials are found to be remarkably similar over the investigated range of rates, temperatures, and strain levels. Below the glass transition temperature (θ_g=80 °C), the materials exhibit a distinct yield stress, followed by strain softening then moderate strain hardening at moderate strain levels and dramatic strain hardening at large strains. Above the glass transition temperature, the stress-strain curves exhibit the classic trends of a rubbery material during loading, albeit with a strong temperature and time dependence. Instead of a distinct yield stress, the curve transitions gradually, or rolls over, to flow. As in the sub-θ_g range, this is followed by moderate strain hardening and stiffening, and subsequent dramatic hardening. The exhibition of dramatic hardening in PETG, a copolymer of PET which does not undergo strain-induced crystallization, indicates that crystallization may not be the source of the dramatic hardening and stiffening in PET and, instead molecular orientation is the primary hardening and stiffening mechanism in both PET and PETG. Indeed, it is only in cases of deformation which result in highly uniaxial network orientation that the stress-strain behavior of PET differs significantly from that of PETG, suggesting the influence of a meso-ordered structure or crystallization in these instances. During unloading, PETG exhibits extensive elastic recovery, whereas PET exhibits relatively little recovery, suggesting that crystallization occurs (or continues to develop) after active loading ceases and unloading has commenced, locking in much of the deformation in PET.