Untersuchungen über das Verhalten organischer Mischphasen 9. Mitteilung Vergleich der binären Systeme Tetrahydrofuran mit Wasser,Methanol und Cyclohexan,Diäthyläther mit Wasser,Methanol und Cyclohexan und Tetrahydrofuran-Diäthyläther

Activities and mixing functions of the following binary systems at 25° C are discussed: 1. mixtures of tetrahydrofuran with water, methanol, and cyclohexane; 2. mixtures of diethyl ether with water, methanol, and cyclohexane, and 3. mixtures of tetrahydrofuran with diethyl ether. Comparison with similar systems shows that in systems containing methanol, the strongest interactions are formation and breaking of hydrogen bonds between alcohol molecules; interactions between methanol and ether molecules play a minor rǒle. Systems containing water exhibit two main kinds of interaction: formation and breaking of hydrogen bonds between water molecules, and formation of hydrogen bonds between water and ether molecules. Deviations from ideality are larger for diethyl ether than for tetrahydrofuran in water and methanol, and smaller in cyclohexane.     

Temperature gradient interaction chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of air terminated polystyryllithium

The reaction products of polystyryllithium with air were characterized by size-exclusion chromatography, temperature gradient interaction chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Polystyryllithium was prepared by anionic polymerization of styrene initiated with sec-butyllithium in cyclohexane under an Ar atmosphere. It was confirmed that polystyryl ketone, polystyryl alcohol, and directly coupled polystyrene were the major products in addition to the normally terminated polystyrene, which is consistent with the results in the literature. We could also identify the presence of methoxy and carboxylic acid end capped polystyrenes as well as dipolystyryl ether as minor products. Among the minor products, dipolystyryl ether has not been reported yet.     

Scope of the allylation reaction with [RuCp(PP)]+ catalysts: changing the nucleophile or allylic alcohol

The scope of the dehydrative allylation reaction using allyl alcohol as allyl donor with [RuCp(PP)]⁺ complexes as catalysts is explored. Aliphatic alcohols are successfully allylated with allyl alcohol or diallyl ether, obtaining high selectivity for the alkyl allyl ether. The reactivity of aliphatic alcohols is in the order of primary > secondary ? tertiary. The tertiary alcohol 1‐adamantanol reacts extremely slowly in the absence of strong acid, but when HOTs is added, reasonable yields of 1‐adamantyl allyl ether are obtained. The alkyl allyl ether is found to be the thermodynamically favored product over diallyl ether. Apart from alcohols, thiols and indole are also efficiently allylated, while aniline acts as a catalyst inhibitor. Allylation reactions with various substituted allylic alcohols give products with retention of the substitution pattern. It is proposed that a Ru(IV) σ‐allyl species plays a key role in the mechanism of these allylation reactions. Copyright © 2010 John Wiley & Sons, Ltd.     

Ionization efficiencies of C3H6, C4H8, C6H12, C2H6O,and C3H8O isomers

Ionization efficiencies of 14 organic compounds have been measured in the wavelength region from 105 to 134nm using an ionization chamber. The compounds examined are cyclopropane, propylene, l-butene, isobutene, cis-and trans-2-butenes, cyclohexane, 1-hexane, tetramethylethylene, ethyl alcohol, dimethyl ether, n-, and iso-propyl alcohol, and ethyl methyl ether. The ionization efficiencies of cyclopropane and cyclohexane monotonically increase with increasing photon energy, but those for the others show a peak or a shoulder in the wavelength region of the present work.     

The solvent extraction of flurazepam and its major metaboutes and their determination by polarography

The solvent extraction of flurazepam and its major metabolites from aqueous solutions of varying pH has been studied at concentrations encountered in body fluids following therapeutic dosage. Distribution ratios have been calculated over the pH range 0–14 and for the solvents, ethyl acetate, diethyl ether, cyclohexane and petroleum ether (40–60°C). Based on this study, a solvent extraction scheme is evaluated for the recovery of such concentrations of these compounds in mixtures, with final polarographic determinations. Recoveries exceeding 95% were found; the method is specific for the determination of flurazepam and its acetic acid metabolite in mixtures. The total concentration of the remaining metabolites, i.e. the hydroxyethyl-, N-1-desalkyl-, and N-1-desalkyl-3-hydroxy metabolites can be estimated after solvent extraction and differential pulse polarography in alkaline solutions.     

Characterization of Heterogeneous Interaction Behavior in Ternary Mixtures by a Dielectric Analysis: Equi-Molar H–bonded Binary Polar Mixtures in Aqueous Solutions

The heterogeneous associating behavior of the aqueous binary mixtures of ethyl alcohol, ethylene glycol, glycerol and mono alkyl ethers of ethylene glycol, and aqueous ternary mixtures of equi-molar binary systems (i.e., mono alkyl ethers of ethylene glycol with ethyl alcohol, ethylene glycol and glycerol) have been investigated over the entire concentration range using accurately measured dielectric constants at 25 ^∘C. The concentration dependent values of the excess dielectric parameter ε^E and effective Kirkwood correlation factor g ^eff were determined using the measured values of the static dielectric constant, ε_o, at 1 MHz and the high frequency limiting dielectric constant ε_∞ = n _D ². The observed ε^E values in aqueous binary and ternary mixtures are negative over the entire concentration range, which implies the formation of heterogeneous complexes between these molecules that reduces the effective number of dipoles. The stoichiometric ratio corresponding to the maximum interaction in alcohol + water mixtures increases with an increase in the number of hydroxyl groups of the alcohol molecules, but for mono alkyl ethers of ethylene glycol + water mixtures it decreases with the increase in the molecular size of the mono alkyl ethers. In aqueous ternary mixtures the stoichiometric ratio for the maximum extent of heterogeneous interaction is governed by the molecular size of the mono alkyl ethers. It was also found that the strength of the heterogeneous H–bond connectivities in the water + alcohol systems decrease with an increase in the number of hydroxyl groups of the alcohol molecules. However in the case of water + mono alkyl ether binary mixtures and in ternary mixtures, the strength of H–bond connectivities increases with the increase in the molecular size of the mono alkyl ether. An analysis of the g ^eff values confirms that the heterogeneous interaction involves the orientation of molecular dipoles in the studied systems.     

Design of composite films and ultrathin membranes of interpolymer complexes

The formation of stoichiometric interpolymer complexes (IPCs) between the poly(vinyl ether) of ethyleneglycol and the copolymer of acrylic acid–butyl vinyl ether, between copolymers of vinyl ether of ethyleneglycol–butyl vinyl ether, and the copolymer of acrylic acid–vinylbutyl ether is demonstrated by conductimetric, potentiometric, viscometric and spectroturbidimetric methods in aqueous solution. The swelling/deswelling behavior of composite films derived from the IPC has been studied in water, alcohol and water–alcohol mixtures, depending on various factors. The formation of polyelectrolyte complexes (PECs) between the copolymer of acrylic acid–vinyl butyl ether and poly(vinyl ether of monoethanolamine) on a dimeric interface of water–butanol has been studied by the potentiometric method. The kinetics of PEC formation on a dimeric interface was measured and the activation energy of this process was calculated. Copyright © 2000 John Wiley & Sons, Ltd.     

Synthetic and structural studies on macrocyclic amino cyclitols--conformational chameleons

Starting from quinic acid the synthesis of 1,4-butanediol-linked macrocyclic aminocyclitols 30, 32, 34, 36 and 38 is described. Assembly was achieved by olefin cross-metathesis of appropriate cyclohexyl allyl ethers followed by ring-closing metathesis of bis-O-allyl homodimers. In all five cases studied, the only products that were formed were those resulting from direct ring-closing metathesis; the formation of larger rings was not detected. These macrocycles exhibited diverse conformational behaviour which included formation of stable separable conformers 31a and 31b as well as conformationally dynamic macrocycles 35 in which a ring flip in one cyclohexane chair conformer induces a ring flip of the other cyclohexane ring through the linking chains of the macrocycles. The activation energy for the inversion of the chair conformation in this process was determined to be about 38 kJ mol(-1), which is about 7 kJ mol(-1) lower than the activation energy for the ring flip of the unsubstituted cyclohexane ring. In all cases, the conformational studies strongly suggest that intramolecular H-bonding between 1,3-diaxially oriented amido and alcohol or ether groups exerts a decisive contribution to the overall stabilisation of the preferred cyclohexane chair conformation.     

2-氨基-4-氯-5-甲基苯磺酸的合成研究

2 氨基 4 氯 5 甲基苯磺酸是合成染料和颜料的重要中间体 ,主要用于合成Ｃ .Ｉ.颜料红等[1] 。目前该产品的合成是以对硝基甲苯为原料 ,经氯化、还原、磺化而成[2 ] 。磺化过程需在压力容器中进行 ,存在成本高 ,溶剂及副产物二氯苯、多氯联苯有毒等问题[3,4] 。为此采用无毒、价廉的汽油和石油醚作为混合溶剂 ,常压下合成 2 氨基 4 氯 5 甲基苯磺酸是本工作的目的。1　实验部分1 .1　主要仪器和药品Ｘ4熔点测定仪 ,日本 2 6 0 5 0型红外光谱仪 ,日本ＬＣ 6Ａ高效液相色谱仪 ,ＪＥＯＬＦＸ 90Ｑ型核磁共振光谱仪 ,美国ＰＥ 2 4 0 0自动元…     

Heats of mixing of some binary methylene chloride solutions

Heats of mixing of pyridine, α-picoline, aniline, o-toluidine and cyclohexane with methylene chloride have been measured at 298.15 K. The results have been considered in terms of molecular interactions between the components of these mixtures and possible structures of the complexes have been described.     

Antioxidative Effect of Schiff Bases with o-Hydroxybenzylidene Groupon Free Radical Induced Hemolysis of Human Red Blood Cell

IntroductionThe recent development of free radical biologyand medicine has provided a great deal of clinicaland experimental evidence indicating that the freeradical induced peroxidation of membrane lipids isassociated with a variety of chronic healthproblems,such as cancer,atherosclerosis andageing[1,2 ] . Both natural and synthetic antioxidantshave been used to trap peroxyl radicals and/orinitiating radicals to protect the membrane lipidsagainst free radical chain reactions,and hence mayhave…     

DIHEMATOPORPHYRIN ETHER-PHOSPHOLIPID INTERACTIONS. THE ROLES OF SURFACE CHARGE and LATERAL PHASE SEPARATIONS

Abstract Fluorescence spectroscopy was utilized to investigate the equilibrium interaction of dihem-atoporphyrin ether(s) (DHE) with binary and ternary phospholipid mixtures of defined composition in order to define the roles of net negative surface charge and lateral phase separations in DHE-membrane partitioning. Binary phospholipid mixtures employed were composed of dimyristoyl-phosphatidylcholine (DMPC) mixed with increasing weight percentages of dimyristoylphosphatidylgly-cerol (DMPG) providing controlled variation of net membrane surface charge. Two types of ternary phospholipid mixtures were utilized. Ternary acid mixtures contained various percentages of palmitoyl-lysophosphatidyl choline (LPC) + palmitic acid (PA) dispersed in DMPC. Ternary alcohol mixtures contained various percentages of LPC + hexadecanol (OL) dispersed in DMPC. The ternary phospholipid mixtures are known to be phase separated. At total DHE concentrations of 0.33 μA/ and using 100% DMPC, the DHE partition coefficient (P) is 250 000. This partition coefficient is to some extent dependent on the DHE concentration. The observed partition coefficients show little dependence on surface charge in DMPC-DMPG mixtures. However, P decreases markedly with increasing phase separation in the ternary lipid mixtures. The fluorescence of membrane-bound DHE is dependent on the composition of the ternary mixtures in a manner suggesting micropartitioning of DHE into the phospholipid bulk phase as well as into the disordered regions between laterally phase separated phospholipid domains.     

红外光谱法研究胺与几种溶质的缔合性质

室温下在3800—3000 cm~(-1)内测定了苯脓、N-甲基苯胺与正庚烷、四氯化碳、苯和甲苯二元混合稀溶液的红外光谱, 考察了溶剂对溶质特征红外光谱的影响。测定了苯胺、N-甲基苯胺与吡啶在四氯化碳中作用的红外光谱, 以及苯胺、N-甲基苯胺、三乙胺、三丁胺和吡啶与乙醇在四氯化碳中作用的红外光谱, 计算了相应的交叉缔合常数, 对不同种分子间的相互作用进行了探讨。几种含氮分子与乙醇缔合时, 给予电子的能力按以下次序递增: 苯胺～N-甲基苯胺<三丁胺<吡啶<三乙胺。此外, 还对乙醇+吡啶+氯仿三元体系的特征红外光谱随溶剂比例的变化进行了分析讨论。     

Chemoselective ester/ether C–O cleavage of methyl anisates by aluminum triiodide

The aluminum triiodide mediated chemoselective ester/ether C–O cleavage of methyl anisates was investigated. o-Anisate undergoes ether cleavage at low temperatures in carbon disulfide, cyclohexane and acetonitrile. Further cleavage of the ester group occurs at elevated temperatures to afford salicylic acid. The cleavage of p-anisate is solvent-dependent. In cyclohexane, the ester and ether groups were cleaved non-selectively to give equimolar amounts of p-anisic acid and methyl p-hydroxybenzoate. The ester group was preferentially cleaved in acetonitrile, compared to ether group cleavage in carbon disulfide. The ester cleavage reaction was improved using pyridine as an acid scavenger additive. Reasons for the contrasting reactivity of anisates towards AlI₃ were explored, and the methods were applied to cleavage of the tert-butyl ester of acemetacin which gave different products under these conditions.     

溴化苄的合成工艺研究

以二苄醚和氢溴酸为原料,SO42-/TiO2为催化剂,环已烷为带水剂,合成了溴化苄。实验分别考察了反应物摩尔比、反应时间、反应温度、带水剂的用量,催化剂的使用量等因素对溴化苄收率的影响,得出了用此方法合成溴化苄的最佳反应条件:氢溴酸与二苄醚的摩尔比为3:1,反应时间为8 h,环已烷为8 mL,SO42-/TiO2催化剂的用量为0.5 g,溴化苄的收率达80.2%。     

Preparation and crystal structures of a series of titanium(III) 9-BBN hydroborate complexes containing Ti...H agostic interactions

9-BBN hydroborate complexes Ti{(mu-H)2BC8H14}3(THF)2 (1), Ti{(mu-H)2BC8H14}3(OEt2) (2), and [K(OEt2)4]-[Ti{(mu-H)2BC8H14}4] (4) were formed from the reaction of TiCl4 with K[H2BC8H14] in diethyl ether or THF. Ti{(mu-H)2BC8H14}3(PhNH2) (3) was isolated from the reaction of 2 with aniline in diethyl ether. In the formation of these complexes, Ti(IV) is reduced to Ti(III). The coordinated diethyl ether in 2 can be displaced by the stronger bases THF and aniline, to form 1 and 3, respectively. All of the compounds were characterized by single-crystal X-ray diffraction analysis. In complex 1, which contains two coordinated THF ligands, the titanium possesses a 17 electron configuration and there is no evidence for agostic interaction. Complexes 2 and 3 contain only one coordinated ether or aniline ligand, and the titanium possesses a 15 electron configuration. In these compounds, a C-H hydrogen on an alpha carbon on the BC8H14 unit of a 9-BBN hydroborate ligand forms an agostic interaction with the titanium. Criteria for assessing the existence of agostic interactions are discussed. As the potassium salt, the anion of complex 4 is more stable than the complexes 1-3. Organometallic anions of the type [ML4]- for titanium(III) are rare.     

Kinetic determination of organic vapor mixtures with single piezoelectric quartz crystal sensor using artificial neural networks

A single piezoelectric quartz crystal coated with one kind of crown ether was applied to the simultaneous determination of binary acid and amine vapor mixtures. From the adsorption and desorption curves of analytes, which were somewhat different in shape, frequency shifts from ten time windows were taken as inputs for artificial neural networks (ANN). Prediction results were satisfactory for ANN in both sample sets. The average relative errors, for formic acid and acrylic acid were 5%, for n-butylamine and aniline, they were 3% with ANN respectively. The effects of number of neurons in the hidden layer of ANN on the performance of the network are also discussed.     

(Liquid + liquid) equilibria in ternary aqueous mixtures of phosphoric acid with organic solvents at T = 298.2 K

(Liquid + liquid) equilibrium (LLE) data for the ternary mixtures of {water (1) + phosphoric acid (2) + organic solvents (3)} were determined at T = 298.2 K and atmospheric pressure. The organic solvents were cyclohexane, 2-methyl-2-butanol (tert-amyl alcohol), and isobutyl acetate. All the investigated systems exhibit Type-1 behaviour of LLE. The immiscibility region was found to be larger for the (water + phosphoric acid + cyclohexane) ternary system. The experimental LLE results were correlated with the NRTL model, and the binary interaction parameters were obtained. The reliability of the experimental tie-line results was tested through the Othmer–Tobias and Bachman correlation equations. Distribution coefficients and separation factors were evaluated over the immiscibility regions and a comparison of the extracting capabilities of the solvents was made with respect to these factors. The experimental results indicate the superiority of cyclohexane as the preferred solvent for the extraction of phosphoric acid from its aqueous solutions.     

二苯并-18-冠-6与杯环芳烃毛细管气相色谱混合固定相的协同效应研究

在气相色谱混合固定相中 ,一直认为具有加和效应 .但近年来我们 [1,2 ] 在研究特殊选择性气相色谱混合固定相时 ,在填充柱气相色谱中发现了协同效应 ,并在气相色谱领域运用协同效应概念( Synergistic Effect) ,而后又在毛细管气相色谱中观察到这种现象 [3,4 ] .由于冠醚有一个洞穴的结构 ,并存在氢键作用 ,因此对很多极性的位置异构体的分离具有高选择性 [5] .杯芳烃也是一个具有洞穴式结构的特殊分子 ,它能与一些金属离子和有机分子形成包合物 ,已被用于分离位置异构体 [6 ] .本文将二苯并 - 1 8-冠 - 6与杯环芳烃的衍生物组成混合固定相 …     

Pervaporation and properties of chitosan-poly(acrylic acid) complex membranes

Polyelectrolyte complex membranes between chitosan as a cationic polyelectrolyte and poly(acrylic acid) as an anionic species were prepared by blending two polymer solutions in different ratio. Characterization of chitosan-poly(acrylic acid) complex membrane was investigated by Fourier transform-infrared (FT-IR), wide angle X-ray diffractometer, dielectric analyzer. Their mechanical properties were studied by universal testing machine. The swelling of polyelectrolyte membranes was studied. Thermal properties of polyelectrolyte membranes from chitosan and poly(acrylic acid) by varying blend ratios showed a shift in transition temperatures of polyelectrolyte complexes. Polyelectrolyte complex membranes from chitosan and poly(acrylic acid) had pH sensitive characteristics as determined by FT-IR studies and swelling behaviors. Pervaporation performances were investigated with various organic mixtures; water-ethanol, water-isopropanol, methanol-methyl t-butyl ether mixtures. An increase of poly(acrylic acid) content in the polyelectrolyte complex membranes affected the swelling behavior and pervaporation performance of water-ethanol mixture. Permeation flux decreased and the water concentration in the permeate was close to 100% upon increasing the feed alcohol concentration.