合成高分子膜透气速率的温度依赖性

近年来以气体选择性分离为目的的合成高分子膜的研究取得了巨大的进步。气体分离膜的两个基本性能参数是透气速率J及选择系数α。同一个膜,在较高温度使用时,往往是J值增大,α值下降,因此选择适当地操作温度,以便得到最佳的J-α搭配是很重要的。本文讨论了甲基硅橡胶(MSR)、天然橡胶(NR)、乙丙橡胶(EPR)、聚乙烯(PE)、聚(4-甲基戊烯-1)(TPX)等材料的均质膜或复合膜,在不同温度下的氧、氮透过速率,计算了各种膜材料的氧、氮表观透过活化能,并对其本质进行了探讨。     

Propane/propylene separation by selective olefin adsorption on Cu/SBA-15 mesoporous silica

Samples of mesoporous silica, SBA-15, were prepared under hydrothermal conditions and Cu cations were incorporated into the framework by two different impregnation techniques. The corresponding adsorption/desorption isotherms of propylene, propane, and N₂ were measured to evaluate the material's effectiveness in the separation of propane/propylene mixtures. Adsorption uptake of propylene increased and that of propane decreased in Cu containing samples as compared to the uptakes observed in undoped SBA-15 samples. It was demonstrated that the presence of Cu atoms in the adsorbent lattice led to a greater selectivity towards propylene. Furthermore, the highest level of Cu(I) were obtained in samples prepared by equilibrium impregnation, which in turn improved the olefin/paraffin uptake ratio. Under some working conditions, the amount of propylene adsorbed in selected samples is totally reversible while propane uptake was negligible.     

Effect of Pluronic F127 on the pore structure of macrocellular biodegradable polylactide foams

Thermally induced phase separation technique was utilized to fabricate biodegradable poly(l ‐lactic acid) (PLLA) macrocellular foams which were capable of being applied in tissue engineering. The block copolymer Pluronic F127 composed of (polyethyleneoxide)‐(polypropyleneoxide)‐(polyethyleneoxide) [(PEO)‐(PPO)‐(PEO)] was used as a porogen. Water/dioxane mixtures with different volume ratios were used as solvents. The addition of Pluronic F127 could induce an appearance of large pores (50–200 μm) besides small pores (10–20 μm) or a change from a solid–liquid phase separation to a liquid–liquid phase separation. The role of Pluronic F127 depends on the water/dioxane ratios in the PLLA/dioxane/water system. The X‐ray diffraction patterns and porosity measurement results showed that Pluronic F127 was crystallized and existed on the pore wall. The effect of Pluronic F127 on changing pore structure is attributed to the occurrence of the interaction of the lipophilic PPO blocks in Pluronic F127 with PLLA clews, consequently, this results in PLLA aggregation and early phase separation on cooling. Copyright © 2004 John Wiley & Sons, Ltd.     

用透射电镜法研究聚(苯乙烯-异戊二烯)二嵌段共聚物微相分离的微区尺寸

本文采用透射电镜(TEM)法,系统地研究了具有不同组成,不同分子量和不同形态结构的聚(苯乙烯-异戊二烯)二嵌段共聚物,并由TEM照片直接测量具有栓状,层状和有规双连续双金钢石(OBDD)结构的PS-PI二嵌共聚物的微区尺寸,讨论了其与分子量的关系。实验证明嵌段共聚物微相分离有规结构的微区尺寸大小与分子量呈2/3的关系。     

Chiral separation of N-(trans-4-isopropylcyclohexylcarbonyl)-D,L-phenylalanine isomers by high performance liquid chromatography

Summary A high-performance liquid chromatographic method was developed for the chiral separation of a new anti-diabetic agent, N-(trans-4-isopropylcyclohexylcarbonyl)-D-phenylalanine, and its L-enantiomer. The separation was performed on a Sumichiral OA-3300 column. Optimized mobile phase was 0.025 mol.L⁻¹ ammonium acetate in methanol solution. UV detection was at 210 nm. Baseline chiral separation was obtained within 12 minutes. The detection limits are 80 pg for the D-enantiomer and 120 pg for the L-enantiomer. RSD of the method was below 1% (n=5).     

Enantiomeric Separation of Omeperazole Enantiomers by Aqueous CE Using UV and MS Detection

This paper details the analysis of the enantiomers of omeprazole, using aqueous CE coupled with MS detection. Following our previously published work: where a non-aqueous CE–UV method was developed for omeprazole and 5-hydroxy-omeprazole; coupling to electro-spray ionization (ESI) MS detection has now been investigated, using a sheath-flow interface for introduction. An aqueous CE method was developed and designed to afford increased compatibility with ESI–MS detection, employing an ammonium acetate buffer system (pH 5.8). Common partial filling methods could not be utilized to avoid the entrance of cyclodextrin into the MS, and therefore a modified method of non-continuous-flow CE–MS was applied, with the CE separation carried out without applied ESI voltage, before reapplying and allowing flow into the MS for data collection. A chiral CE separation of omeprazole and 5-hydroxyomeprazole was achieved, and chiral CE resolution of omeprazole has been demonstrated using MS detection.     

活性碳分离碳－60和碳－70

活性碳用苯胺处理后，可以减少对Ｃ＿（６０）和Ｃ＿（７０）的不可逆吸附，从而增加Ｃ＿（６０）和Ｃ＿（７０）的分离收率，同时提高了Ｃ＿（７０）的纯度。     

使用手性冠醚及手性柱的HPCE和HPLC法拆分伯胺类药物对映体的对比研究

报道了在缓冲液中添加 1 8-冠 - 6 -四甲酸 (1 8C6 H4 )的高效毛细管电泳法(HPCE)对 8个含氨基的药物进行拆分 ,低 p H值 (2 .0 6 )和较高浓度的 Tris缓冲液(2 0 mmol· L- 1)可加快手性分离。用手性柱 Crownpak CR(+)的高效液相色谱(HPLC)法对与前相同的 8个含氨基药物进行拆分 ,甲醇浓度增大 ,分离度 RS值有所减小。实验结果还表明 ,使用 HPCE法拆分的各物质 RS值大于使用 HPLC法拆分相应物质的 RS值。     

Thermal Properties of Hot-Stage Extrudates of Itraconazole and Eudragit E100. Phase separation and polymorphism

Solid dispersions of itraconazole and eudragit E100 were prepared by hot-stage extrusion. Analysis of the physical structure revealed the existence of different phases, depending on the manufacturing condition. Extrudates prepared at 453 K existed as a molecular dispersion of itraconazole in eudragit E100 when the drug concentration did not exceed ca. 13% mass/mass. At higher concentrations, a second phase consisting of pure glassy itraconazole emerged. In other dispersions prepared at 413 K, the second phase consisted of pure crystalline itraconazole. The difference can be attributed to the relation of the process-temperature to the melting point. Heating of both dispersions induced cold crystallization. Extrudates prepared at 453 K showed comparable behavior before and after milling, with the exception that unmilled dispersions with a drug load of ≥60% mass/mass recrystallized upon heating into a polymorphic modification of itraconazole (T _m=431 K). Upon further heating the polymorph recrystallized to the stable crystalline form (T _m=441 K). This revised version was published online in August 2006 with corrections to the Cover Date.     

微波辐照增强原煤磁分离脱硫机理探讨

采用~(57)Fe穆斯堡尔谱学方法,研究微波-磁分离法脱硫机理及微波辐照深度对脱硫率的影响。结果表明,微波选择性介质加热,可以激励煤中顺磁性黄铁矿FeS_2热解,使其转化为非化学计量的磁黄铁矿Fe_(1-x)S(0相似文献