藻朊酸钠对有机液／水混合物的渗透汽化分离Ⅰ．膜的渗透汽化特性

研究了藻朊酸钠均质膜对有机液／水混合体系的渗透汽化特性。结果表明，藻朊酸钠对甲醇、乙醇、异丙醇、丙酮、四氢呋喃及二氧六环等有机溶剂同水的混合液均表现为水优先透过，其渗透通量及选择分离系数都非常高。对８０ｗｔ％的四氢呋喃水溶液，５５℃下，通量Ｑ达到２４８９ｇ／ｍ２·ｈ，水对四氢呋喃的分离系数趋于无穷大；对８０ｗｔ％的二氧六环水溶液，Ｑ为２８６２ｇ／ｍ２·ｈ，分离系数为３９９９６（６０℃）。通量与温度间呈Ａｒｒｈｅｎｉｕｓ关系。比较了两种藻朊酸钠样品对有机液／水混合体系的渗透汽化特性，讨论了化学组成、结构的不同，对膜性能的影响。     

极性非质子溶剂与甲醇或1,2-二氯乙烷的汽液平衡

使用双沸点仪测定了丙酮、乙酸乙酯、对二氧六环、乙腈或三乙胺与甲醇或1,2→二氯乙烷以及二者混合物等十一组二元体系在99.3 kPa下的汽液平衡数据(T,x,p), 计算了有关体系的过量吉布斯自由能。结果表明, 六种非质子溶剂与甲醇组成的二元系GE>0; 乙腈或三乙胺与1,2-二氯乙烷组成的二元系GE>0, 而丙酮、乙酸乙酯或对二氧六环与1,2-二氯乙烷的二元混合物GE<0。从同种分子间或不同种分子间的缔合作用对上述结果进行了讨论。本文还在固定极性非质子溶剂(第三组分)物质的量浓度的条件下, 测定了非质子溶剂+1,2-二氯乙烷+甲醇三元混合物的汽液平衡数据, 考察了非质子溶剂的加入对甲醇+1,2-二氯乙烷二元系GE的影响。     

甲酸-乙酸-水-醋酸钠体系汽液平衡的盐效应

采用Otsuki-Williams式汽液平衡釜测定了甲酸-乙酸-水-醋酸钠体系在9.866×10⁴Pa下汽液平衡数据。醋酸钠的加入量为2mol/(kg溶剂)。结果表明:醋酸钠对体系起物理化学作用,也起化学作用。它涉及到了两种盐对各组分的盐溶、盐析和盐效应的不规则现象。根据实验数据,绘制了汽液平衡相图、各组分挥发度等于1的曲线和甲酸-乙酸在体系中相对挥发度等于1的曲线,用以判别、分析盐效应的作用。     

甲酸,乙酸或水单一溶剂的偶极矩与盐浓度的关系

近十几年来,汽液平衡盐效应的研究一直是国内外十分活跃的课题.但是,对于多组分含盐体系,特别是多组分羧酸体系,如甲酸-乙酸-水-盐体系的汽液平衡盐效应研究报道甚少。一方面因为多元汽液平衡盐效应的测定较难;另一方面由于盐的加入,使原来的强极性、强缔合的羧酸体系变得更为复杂,给热力学关联带来了困难.尽管有的关联方法引入盐后引起偶极矩改变,且使偏心因子产生相应变化,但在实验上并未得到偶极矩随盐浓度定量变化的关系。     

甲酸—乙酸—水—氯化钙体系汽液平衡盐效应（Ⅱ）

研究了加入恒定浓度分别为0.8和1.0 mol/(kg溶剂)的氯化钙的甲酸-乙酸-水体系的汽液平衡盐效应以及盐浓度对体系汽液平衡盐效应的影响。用汽液相等浓线及所划分的区域和等挥发度线分析判别了盐浓度对盐效应的影响以及由此引起的各区域挥发度的变化情况。结果表明,氯化钙对甲酸、乙酸的盐析效应随盐浓度增加而增强。     

甲酸—乙酸—水—氯化镁体系汽液平衡中的盐效应

采用Otsuiki-Williams式汽液平衡仪在9.866×10~4Pa下测定了甲酸-水、乙酸-水、甲酸-乙酸、甲酸-乙酸-水体系无盐和加氯化镁后各体系的汽液平衡数据,绘制了两组分和三组分体系相图。相图表明氯化镁有明显的盐效应。     

有机改性剂对胶束电动毛细管色谱中电渗和电泳迁移的影响

考察了尿素，二氧六环，甲醇和四氢呋喃等四种有机改性剂对胶束电动毛细管色谱中电渗淌度，十二烷基硫酸钠胶束电泳淌度以及电渗和胶事的淌度比的影响。结果表明：电渗淌度的ＳＤＳ胶束电泳淌度随要肌改性剂浓度的增加线性地降低，直线斜率的负值分别表征了有机改性剂对电渗淌度和胶束电泳淌度降低的作用的大小，Ｄｃｏ和Ｄｅｐ，ｍｃ值大小顺序为：尿素〈甲醇〈二氧六环Ｍ〈四氢呋喃；有机改性剂浓度的增加线性地增加淌度比，四种有     

甲酸-乙酸-水-氯化钙体系汽液平衡盐效应的研究

本文采用Otsuki-Williams式汽液平衡釜测定了甲酸-乙酸-水体系及甲酸-乙酸-水-氯化钙体系在98658.28Pa下汽液平衡数据。氯化钙的加入量为0.5mol/(kg溶剂)。结合盐效应的作用情况,对相图进行了分析。研究结果表明:氯化钙的加入对体系起了物理化学作用,它与盐溶、盐析现象有关。     

聚(N-乙烯基己内酰胺)在二元水溶液中的温度响应性相变行为

用浊度法研究了聚(N-乙烯基己内酰胺)(PNVCL)在不同浓度的几种非质子溶剂如二甲基亚砜(DMSO)、N,N-二甲基甲酰胺(DMF)、四氢呋喃(THF)、1, 4-二氧六环和质子溶剂(几种低级醇)的水溶液中低临界溶液温度(LCST)的变化情况。结果表明:PNVCL的LCST随DMF、THF、1, 4-二氧六环和CH_3OH在其水溶液中浓度的增加而升高,其中DMF和1, 4-二氧六环对PNVCL的LCST的影响较大,其次是THF,而甲醇对其LCST的影响最小。乙醇、1-丙醇、2-丙醇在低浓度时导致PNVCL的LCST降低,随着浓度增加其LCST升高。与其他溶剂不同的是DMSO,PNVCL的LCST随DMSO在水溶液中浓度的增加先升高后下降。     

极性—非极性双液体系汽液平衡盐效应参数的测定与计算

测定了苯—甲醇— 1_1型电解质 (LiCl、NaBr、KI)、四氯化碳—甲醇— 1_1型电解质 (LiCl、NaBr、KI)两个体系在恒压 ( 1 0 1 .3kPa)条件下的汽液平衡盐效应参数。理论计算以Pierotti的定标粒子理论为基础 ,硬球作用项采用Masterton -Lee方程计算 ,软球作用项采用胡英等人建议的简化的径向分布函数 ,分子间力在Lennard -Jones位能函数基础上计入极性分子间偶极—偶极、偶极—诱导偶极 ,离子与极性分子间的电荷—偶极以及离子与分子间的电荷—诱导偶极的贡献 ,并根据溶剂性质和溶液结构作出一些合理的假设。在此基础上 ,理论计算与实验结果基本相符。     

Enhanced energy transfer from diolefinic laser dyes to meso-tetrakis (4-sulfonatophenyl) porphyrin immobilized on silver nanoparticles: DFT,TD-DFT and spectroscopic studies

Porphyrin derivatives are known singlet oxygen sensitizers in photodynamic therapy (PDT). Energy transfer from a class of diolefinic laser dyes (DOLDs) as energy donors to the sodium salt of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) as the accepter of energy would extend the range of photon harvesting down to the UV-region. Energy transfer was substantially enhanced in the presence of metallic silver nanoparticles (AgNPs), as revealed by steady-state emission spectroscopy, lifetimes, and quantum mechanics. DOLDs under investigation are 2,5-distyrylpyrazine (DSP), 1,4-bis (β-pyridyl-2 vinyl) benzene (P2VB), and 1,4 bis (2-methylstyryl) benzene (MSB) as efficient donors of intense absorption in the UV-region. AgNPs enhance the rate of energy transfer from DOLDs to TPPS via bringing donor and acceptor into close- proximity with a concomitant increase in dipole–dipole interaction between excited state donor and ground-state acceptor. The DOLDs molecular structures were optimized using the DFT/CAM-B3LYP/6-311G++ (d, p) level of theory. The calculated electronic absorption spectra for the studied DOLDs in the gaseous phase and methanol solvent were studied using the time-dependent density functional theory (TD-DFT) at M06-2X/6-311G++ (2d,2p) level. The calculated absorption/emission spectra for DSP laser dye in methanol are obtained at the TD/ M06-2X/6-311G++(2d, 2p) method. Notably, all theoretical results of the molecular structures under study highly agreed with the practical optical results. Energy transfer rate constants (k_ET) amid energy donor/acceptor pairs were determined by Stern-Volmer constants (KSV) and donors' lifetime measurements. The KSV values indicate an enhanced Fluorescence Resonance Energy Transfer (FRET) efficiencies in the presence of negatively charged AgNPs. The critical transfer distances R_o were determined from the spectral overlap between the emission spectrum of donor and absorption spectrum of TTPS. These outcomes propose the application of designed metal-enhanced FRET for energy-transfer-based assays and photodynamic therapy (PDT) applications.     

Effect of chromophore-charge distance on the energy transfer properties of water-soluble conjugated oligomers

The synthesis of 1,4-bis(9,9'-bis(3"-(N,N,N-trimethylammonium)-propyl)-2'-fluorenyl)benzene tetrabromide (C3), 1,4-bis(9,9'-bis(4"-(N,N,N-trimethylammonium)-butyl)-2'-fluorenyl)benzene tetrabromide (C4), 1,4-bis(9,9'-bis(6"-(N,N,N-trimethylammonium)-hexyl)-2'-fluorenyl)benzene tetrabromide (C6), and 1,4-bis(9,9'-bis(8"-(N,N,N-trimethylammonium)-octyl)-2'-fluorenyl)benzene tetrabromide (C8) is reported. Fluorescence energy transfer experiments between C3-C8 and the acceptors pentasodium 1,4-bis(4'(2",4"-bis(butoxysulfonate)-styryl)styryl)-2-(butoxysulfonate)-5-methoxybenzene (3), fluorescein labeled single-stranded DNA and fluorescein labeled double-stranded DNA in water, buffer, and methanol reveal the importance of hydrophobic and electrostatic forces in determining chromophore-chromophore close proximity. In water, the oligomers with longer side chain length show better energy transfer, as well as higher Stern-Volmer quenching constants (K(sv)), largely due to a stronger hydrophobic attraction between the optically active components. In methanol, the differences in energy transfer are leveled, and the oligomers with shorter side chain lengths show higher K(sv) values. Compounds C3, C4, C6, and C8 were also used to dissect the different contributors to DNA hybridization assays based on cationic conjugated polymers.     

Synthesis of a novel 8-thia-1,4-diazacycl[3.3.2] azine

A unique covalently hydrated cyclazine adduct, 2-imino-6a-hydroxy-4,5,6,6a-tetrahydro-7H-8-thia-J, 4-diazacycl[3.3.2]azin-5-one hydrochloride was prepared by reacting ethyl 4-chloro-acetoacetate with 4,6-diamino-2-thiopyrimidine in neutral alcohol. Neutralization gave 2-imino-5,6a-dihydroxy-6,6a-dihydro-7H-8-thia-1,4-diazacycl[3.3.2]azine which decomposed to 4,6-diamino-2-acetonylthiopyrimidine upon heating in water. Warming the hydrated hydrochloride in concentrated hydrochloric acid caused dehydration to yield 2-imino-5-hydroxy-6H-8-thia-1,4-diazacycl[3.3.2]azine hydrochloride. Partial isomerization (20%) to 2-imino-5-hydroxy-7H-8-thia-1,4-diazacycl[3.3.2]azine hydrochloride occurred during recrystallization from aqueous acidic methanol. The free base, 2-imino-5-hydroxy-7H-8-thia-1,4-diazacycl[3.3.2]azine was obtained after neutralizing either of the tautomeric hydrochlorides. Treating the free base with trifluoroacetic acid produced a mixture of the trifluoroacetate salts of the two tautomeric bases. Isomerization of one trifluoroacetate salt into the other in trifluoroacetic acid was observed by pmr at room temperature. Both 2-amino-5-hydroxy-7-nitroso-8-thia-1,4-diazacycl[3.3.2]azine and 2-amino-5-hydroxy-6-nitroso-8-thia-1,4-diazacycl[3.3.2]azine were isolated after nitrosation of the hydrochloride mixture.     

Ion-solvent interactions of silver(I)-18-crown-6 perchlorate complex in methanol-acetonitrile mixtures

The standard Gibbs transfer energies of the silver(I)-18-crown-6 perchlorate complex salt from methanol to various compositions of methanol-acetonitrile mixtures were determined from solubility measurements at 30°C and these data were separated into the corresponding ionic contributions by employing the negligible liquid junction potential method of Parkeret al. The solvent transport numbers _AN, for the salt were also determined at various solvent compositions using a concentration cell with transference.The Gibbs transfer energy of the silver(I)-18-crown-6 complex cation is negative and decreases with the addition of acetonitrile but the transfer energy of the anion is positive and increases under the same conditions. The solvent transport number, _AN, increases and passes through a maximum value of 5.48 at _AN=0.55. These results indicate that the complex salt is heteroselectively solvated in these mixtures with the cation being preferentially solvated by acetonitrile and the anion by methanol molecules.     

新型亲水整体柱的制备及其在毛细管液相色谱和加压电色谱中的应用

以N,N-二甲基-N-甲基丙烯酰胺基丙基-N,N-二甲基-N-丙烷磺酸内盐(SPP)为单体,季戊四醇三丙烯酸酯(PETA)为交联剂,偶氮二异丁腈(AIBN)为引发剂及两类不同的致孔剂(乙醇/乙二醇和甲醇/1,4-丁二醇)制备了两种新型亲水性整体柱。为了获得理想的柱效、电渗流速度和渗透性,对制备整体柱的各反应物配比进行了研究和优化。比较了两种整体柱在渗透性和分离样品方面的性能,结果表明,以乙醇/乙二醇为致孔剂制备的整体柱在柱效、分离度方面优于以甲醇/1,4-丁二醇为致孔剂制备的整体柱,但在渗透性方面不及后者。探讨了流动相中盐浓度对核苷类样品保留的影响,发现当甲酸铵浓度从10 mmol/L增加到70 mmol/L时,核苷样品的保留因子呈现先增加后减小的状态。将制备的整体柱用于毛细管液相色谱和加压电色谱分别分离胺类、酚类和核苷类样品,获得了理想的分离效果。在分离酚类和核苷类混合样品时,发现加压毛细管电色谱在分离度和分离速度上均优于毛细管液相色谱。     

铜（II）化合物作用下2-綦胺的氧化偶合反应

2-萘胺（1）在甲醇中与铜胺络合物[x(CuCl_2):x(苄胺或乙醇胺）=2：1]室温 下反应得到产率为74%的1,1'-联-2-萘胺（2）。在醋酸铜、硝酸铜或高氯酸铜的催 化下,1在甲醇中被氢气氧化为2-氨基-1,4-萘醌-4-2'-萘亚胺（3）,产率86%。 用X-ray单晶衍射证实3的乙酰化产物结构为2-乙酰氨基-1,4-萘醌-E-4-2'-萘亚胺 （4）。循环伏安研究表明,铜（II）化合物的氧化反应选择性与其还原峰电位有 关。电喷雾质谱的分析表明1,2-萘醌-2-亚胺（6）是生成3的中间体。     

Cloning and expression of two genes coding endo-β-1,4-glucanases from <Emphasis Type="Italic">Trichoderma asperellum</Emphasis> PQ34 in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

Two genes coding endo-β-1,4-glucanases were cloned from Trichoderma asperellum PQ34 which was isolated from Thua Thien Hue province, Vietnam. The expression of these genes in Pichia pastoris produced two enzymes with molecular masses of approximately 46 kDa (about 42 kDa of enzymes and 4 kDa of signal peptide). The effects of induction time and temperature, inducer concentration, and culture medium on the endo-β-1,4-glucanase activity were investigated. The results showed that the highest total activities of two endo-β-1,4-glucanases were approximately 4.7 × 10^?8 kat (from Glu1-TA gene) and 7.3 × 10^?8 kat (from Glu2-TA gene) occurred after 4 days of induction using 25 mL L^?1 methanol at 30?C when the yeast cells were cultured in a YPL medium.     

A combined time-resolved and stereospecific deuterium labelling study of the elimination of methanol from the molecular ion of methoxycyclohexane

It is shown by field ionization kinetics in combination with both site-specific and stereospecific D-labelling that the loss of a molecule of methanol from the molecular ion of methoxycyclohexane can occur via 1,4- and 1,3-eliminations. The 1,4-elimination predominates at molecular ion lifetimes of ≥10^?10.1 s. It is found that ～19% of this reaction channel corresponds to a stereospecific cis-elimination, whereas the remaining 81% is only site-specific. At molecular ion lifetimes of between 10^?10 and 10^?9 s, a very sudden increase of the 1,3-elimination is observed at the expense of the 1,4-elimination. A stereospecific loss of methanol, however, is not observed at all for the 1,3-elimination within the limits of error. Possible intermediates and reaction pathways, which can account for the observations made, are discussed.     

Green Synthesis of a Novel Functionalized Tetrahydro-1,4-thiazepine and Computational Studies of Its Tautomeric Structures

Reaction of ethyl-2-cyano-3,3-dimercaptoacrylate dipotassium salt with 2-chloroethylamine hydrochloride in water afforded the novel (4E,6E)-ethyl 5-amino-2,3-dihydro-7-mercapto-1,4-thiazepine-6-carboxylate. The molecular geometry of the most stable tautomeric structure was investigated with DFT and AIM at the B3LYP level of theory using the 6-31G** and 6-311+G** basis sets.     

Neutral species from "non-protic" N-heterocyclic ionic liquids

Possible isomerisation of 1,2,3-trialkylimidazolium and 1-alkylpyridinium ion pairs by proton transfer and by the nucleophilic addition of the anion to the cation have been investigated at the B3LYP/6-31+G* and B3LYP/6-311+G** levels of density functional theory. The deprotonation energies of 1,2,3-trialkylimidazolium and 1-alkylpyridinium cations to diaza-pentafulvene and pyridinium-ylide, respectively, were only slightly larger than that of 1,3-dialkylimidazolium salts yielding N-heterocyclic carbenes. Accordingly, in the case of 1,2,3-dialkylimidazolium salt ion pairs the stability of the H-bonded complex between the fulvene and the corresponding acid can be comparable to that of the ion pair in the presence of sufficiently basic anions, such as acetate. In the case of the pyridinium salts the nucleophilicity of the cation dominates over the acidity, and the formation of 1,2- or 1,4-dihydropyridine derivatives is preferred over proton transfer.