胺型键合反相固定相的制备及评价

首次将一种新型硅烷偶联剂--β-（3，4-环氧环已基）乙基三甲氧基硅烷（β-ECTS）与辛胺反应，然后再键合到硅胶上，得到了胺型键合固定相，并用元素分析、^13C固体核磁共振、红外光谱进行了表征。以甲醇和水为二元流动相，用包括碱性、酸性和中性有机化合物在内的混合物对该固定相进行评价，并考察了该填料的适用pH范围及水解稳定性。结果表明，该固定相具有较好的色谱性能，且在pH=2-8之间稳定性能良好，可有效地用于碱性化合物的分析分离。     

双胺型键合固定相的制备及评价

首次将一种新型硅烷偶联剂β－（3，4－环氧环己基）乙基三甲氧基硅烷（β－ECTS）与己二胺反应，然后再键合到硅胶上，最后与辛酰氯反应得到双胺型键合固定相，并用元素分析、^13C固体核磁、红外光谱进行了表征，用中性、酸性和碱性有机化合物为探测因子对其进行色谱评价。结果表明：该固定相对含氮有机化合物的分离涉及疏水作用和离子排斥双重机理。     

聚N-异丙基丙烯酰胺硅胶键合固定相的制备与评价

以3-巯丙基三甲氧基硅烷为偶联剂,将聚N-异丙基丙烯酰胺(PNIPAM)键合到硅胶上,制得了键合固定相（SI-PNIPAM）填料,并用元素分析、红外光谱等对其进行了表征。以甲醇-水为二元流动相,用多环芳烃、碱性物质对该固定相进行了色谱评价,并考察了该固定相的适用pH范围及水解稳定性。结果表明:该固定相具有较好的色谱性能与温敏特性,并且在pH 2.5～7.5时稳定性良好。     

十二烯基丁二酸改性氧化锆色谱固定相性能研究

本文用十二烯基丁二酸（DSA）改性氧化锆得到一种新的锆基质色谱固定相。改性前后的红外光谱的差异表明，DSA以两个羧基与氧化锆结合，由于多位点结合方式提高了固定相的稳定性，因此固定相可以在碱性（pH8．5）条件下稳定使用。锆基质色谱固定相具有较强的疏水性，用于中性及碱性化合物的分离取得了满意的结果。     

用于碱性物质分离的酰胺型反相色谱键合相的制备及评价

 采用先对硅胶进行氨丙基化 ,然后与辛酰氯键合的方法 ,在国内首次制备了“内嵌”极性官能团酰胺键的反相色谱填料。以甲醇 水为二元流动相 ,用含有中性、酸性和碱性有机化合物的混合物评价了该固定相的疏水性、选择性和亲硅醇基效应 ,并考察了该填料适用的 pH值范围及水解稳定性。结果表明 ,该固定相具有较好的色谱性能 ,且在 pH 2 5～ 7 5时稳定性能良好 ,可有效地用于碱性化合物的分离分析。     

β—环糊精键合固定相合成方法和色谱性能研究

以两种不同的路线合成β－环瑚精－环氧丙氧丙基键合硅胶固定相（β＿ＣＤ－ＧＰＳ）。比较了两种方法得到的键合相的键合量。采用非水滴定法考察了影响键合反应的因素。选择了合成β＿ＣＤ－ＧＰＳ最佳反应条件，并对其色谱性能进行了考察。     

碳十八键合锆胶固定相的制备与色谱性能评价

用诱导聚合胶体凝聚法（PICA）制得的二氧化锆微球与碳十八三乙氧基硅烷反应制备了碳十八键合锆胶固定相（ODZ），评价了该柱填料的色谱性能，并用此固定相分离了中性和碱性化合物。     

氧化锆固定相反相高效液相色谱法测定碱性化合物的离解常数

研究了烷基键合氧化锆微球固定相(C12-ZrO2）的化学稳定性及其对碱性化合物的色谱保留特征,发现C12-ZrO2在pH为2~12时稳定,碱性化合物在该固定相上为典型的反相色谱保留机理。基于对碱性化合物的保留因子与流动相pH关系的考察,建立了碱性化合物离解常数的测定方法。测定了13种典型芳香胺和吡啶衍生物的离解常数,与文献结果对比,其差值在-0.27～0.35 pH单位范围内,说明该方法能够用于碱性化合物离解常数的快速测定。     

酰胺型键合相的简便制备及评价

 提供了一种酰胺型键合相的简便合成方法 ,即氨丙基三乙氧基硅烷先与烷基酰氯反应 ,然后再键合到硅胶上。该合成路径具有很好的重复性 ,得到的最后产物的硅胶表面键合链均一。用元素分析、核磁共振和红外光谱对最后产物进行了表征。以甲醇和水为二元流动相 ,用包括碱性、酸性和中性有机化合物在内的混合物对该键合相进行了评价 ,并考察了该键合相的适用pH范围及水解稳定性。结果表明 ,该键合相具有较好的性能 ,且在 pH 2 5～ 7 5时稳定性能良好 ,可有效地用于碱性化合物的分析分离。     

乳酸烷基酯在接枝聚硅氧烷β-环糊精固定相的手性拆分

采用新合成的手性接枝聚硅氧烷β－环糊精（二环「２，６－二－０－戊基－３－０－已烯基（－５）」五环「２，６－二－０－戊基－３－０－甲基」－β－ＣＤ－聚硅氧烷）固定相制备了毛细管气相色谱柱，对合成的不对称化合物乳酸烷基进行了有效的手性拆分，结果表明该固定相具有良好的手性分离能力。     

葡萄糖苷特异性固相萃取固定相的合成、表征及应用

以马来酰亚胺基修饰凝胶载体,通过β-葡萄糖胺和2-亚氨基硫代烷盐酸盐将作为配基的β-葡萄糖脒连接到载体上,合成了一种葡萄糖苷特异性固相萃取固定相,并对其固相萃取性能进行了表征.该固定相对葡萄糖苷具有特异性识别,并成功用于固相萃取分离葡萄糖苷.     

反相液相色谱中固定相和流动相对柱相比的贡献

依据柱相比的热力学定义和反相液相色谱中溶质的计量置换保留理论(the stoichiometric dispheement heory of solute for retention，SDT-R)，对反相液相色谱中固定相和流动相性质、温度对柱相比的影响进行了研究。结果表明：固定相的种类和配基的疏水性对柱相比影响较大，而流动相中有机溶剂的种类，特别是脂肪酸作为置换剂时，对柱相比的影响更大，而柱相比受温度的影响较小。此外，通过用27种小分子溶质对柱相比的测定，其logI和Z良好的线性关系，进一步证明柱相比是一个与溶质性质无关的常数。     

Morphological studies of a hydrogen-bonded LC polymer obtained by photopolymerization in LC solvents

Anisotropic morphologies and the phase behaviour of a hydrogen-bonded LC polymer obtained by photopolymerization in two kinds of LC solvent are discussed. The hydrogen-bonded LC monomer, 4-(6-acryloyloxyhexyloxy) benzoic acid (A6OBA), was photopolymerized in 4-cyano-4′-hexyloxybiphenyl (6OCB) and in 4-cyano-4′-undecyloxybiphenyl (11OCB), which show a nematic phase and a smectic A phase, respectively. After photo-polymerization, the LC media were removed by extraction and the pure polymer was observed by scanning electron microscopy. SEM images showed that the polymer possessed fibrous morphology with a fibre diameter of a few micrometers, based on polymerization-induced phase separation. The overall geometries reflected typical LC characteristics such as schlieren and focal-conic fan textures. It was found that the hydrogen bond between benzoic acid groups in the monomer was rigid enough to fix the anisotropic phase-separated structure forming during the early stage of phase separation; however, it could not permanently maintain the fibre structure due to dissociation at elevated temperature. X-ray measurements revealed that a well developed layer structure of the hydrogen-bonded mesogen existed in the polymer obtained from the smectic phase of 11OCB, whereas a polymer layer structure could develop only partially from the nematic phase of 6OCB.     

亲水有机相-含盐水两相体系的形成机理与分相能力

亲水有机相-含盐水两相体系的形成机理与分相能力;亲水有机相;含盐水相;两相体系;分相机理;分相能力     

Oxadiazole-based unsymmetrical chiral liquid crystal dimers: synthesis and mesomorphic properties

The synthesis and liquid crystalline properties of novel chiral Schiff's base dimers containing the 1,3,4-oxadiazole ring are reported. The length of the terminal S-alkyl chain has been varied. All the compounds synthesised were thermally stable and exhibited enantiotropic mesomorphism, showing either SmC*–SmA–TGB–N*–BP or SmC*–SmA phase sequence.     

Cholesterol-based dimeric liquid crystals: synthesis,mesomorphic behaviour of frustrated phases and DFT study

Chiral unsymmetrical dimeric liquid crystals consisting of a cholesterol moiety as chiral entity and a substituted salicylidene imine core (with the substituent being butyl or fluoro or chloro group) interconnected through an even methylene spacer have been synthesised and their mesomorphic properties are characterised. All the dimers exhibit enantiotropic mesophases. The butyl homologue exhibited N* phase only, the fluoro- and chloro-substituted compound exhibited frustrated blue phases (BPs), N* phase and SmC* or twisted grain boundary (TGB) phases. The occurrence of a fluid frustrated phase, the BP, in particular, observed in compounds with a polar moiety and bent optimised conformation by density functional theory (DFT) study, indicates the importance of polar structures and bent shape of the compounds. Theoretical calculation was performed in order to study the optimised conformation, polarity and electron density distribution of the synthesised cholesterol derivatives using DFT. Time-dependent density functional theory (TD-DFT) calculation also had been carried out to investigate the absorption spectra and HOMO–LUMO energies. The experimental and theoretical absorption spectra are also presented.     

Preorganised effects of a tetramesogenic supermolecule on supramolecular assembly in the liquid crystalline phases

After preparing a homologous series of tetrameric mesogenic compounds in which two U-shaped molecules were connected via a rigid benzene derivative or a flexible alkyl chain, we investigated their phase transition behaviour using optical microscopy, differential scanning calorimetry and X-ray diffraction analysis. The compounds possessing an alkyl spacer as the central group exhibited nematic and smectic A phases just as the corresponding U-shaped molecule did. The compound possessing a 1,2-benzene unit as the connecting group showed nematic and smectic A phases, although the compound possessing a 1,3-benzene unit exhibited only an anticlinic smectic C phase. Structure–property relations of the liquid crystalline tetramers are interpreted in terms of preorganised effects of the four mesogenic units.     

Time‐Resolved Phase Transitions of the Nanocrystalline Cubic to Submicron Monoclinic Phase in Zirconia

The nanocrystalline cubic, tetragonal, and submicron monoclinic phases of pure zirconia were prepared by thermal decomposition of carbonate and hydroxide precursors. The crystallization and isothermal phase transformations of the oxide were studied using high temperature X‐ray diffraction, X‐ray diffraction and Raman spectra of quenched samples. Cubic zirconia formed first, and then progressively transformed to tetragonal and monoclinic phases at temperatures as low as 320°C. The cubic, tetragonal, and monoclinic phases for ZrO₂ were found to be distinct functions of crystallite size, indicating the nanocrystalline nature of these phases. They were found to exist within critical size ranges of 50 to 140 Å, 100 to 220 Å and 190 to 420 Å (±5 Å), respectively. Thus, as the crystallites grow during annealing, they first transform from cubic to tetragonal and then from tetragonal to monoclinic at critical sizes. The classical Avrami equation for nucleation and growth was applied to the tetragonal to monoclinic phase transition.     

Phase equilibria in the GeSe2-SnTe system

Journal of Thermal Analysis and Calorimetry - The phase diagram of the system GeSe2-SnTe is studied by means of X-ray diffraction, differential thermal and measurements of the microhardness and the...     

Physical properties of two systems with induced antiferroelectric phase

Two ferroelectric three‐ring chiral esters, one with a partially fluorinated alkyl chain and another with a cyano terminal group, were mixed with a structurally similar compound having an alkyl terminal chain. In their mixtures an antiferroelectric phase was induced. The phase behaviour, spontaneous polarisation, tilt angle, smectic layer spacing and helical pitch of both systems were determined. The mechanism of the induction of an antiferroelectric phase is different in both cases, with highly tilted phases in former system and less tilted phases in the latter.