Conductance studies in amide-water mixtures. II. Sodium salts inN,N-dimethylformamide-water mixtures at 35°C

Conductance data for sodium nitrite, chloride, and acetate in water andN,N-dimethylformamide (DMF)-water mixtures (74.82D42.48) for the concentration range 0.001–0.04N, as well as the densities, viscosities, and dielectric constants of the solvent mixtures at 35°C, are reported. The data have been analyzed by the Fuoss (1975) equation. The existence of a maximum in the viscosity at a 13 mole ratio of DMF and water is indicated. The Walden products for all the three salts pass through a maximum while the equivalent conductances show a minimum with increasing DMF content. The maxima in the Walden product are attributed to the dehydration of ions by the cosolvent (DMF).Part I:Indian J. Chem. 14A, 1015 (1976).Deceased.     

Natriumkomplexe mit Salicylideniminen: Synthesen,Strukturen, CO2‐Aufnahme und Carboxylierung von 2‐Fluorpropiophenon bzw. Estronmethylether

Chiral salicylidenphenethylamines (R)‐HA or (S)‐HA , 2‐salicylidenfurfuryl‐imines HB , and 2‐salicylidenaminoethanol HC react with sodium hydride or sodium hexamethyldisilylamide to form the sodium complexes [Na(R)‐A] ₄ · 0,5 Et ₂ , [Na(S)‐A] ₄ · 0,5 Et ₂ O (1) , [NaB] ₄ · 0,5 Ph‐Me (2) and [(dme)NaC] ₄ (3) . In the presence of 18‐crown‐6 the complex [Na(18‐crown‐6)(thf) ₂ ] ₂ [Na ₂ (C)] ₄ · THF (4) can also be isolated. The crystal structure analyses of both 1 and 2 show that heterocubane structures with a Na₄O₄ frame work are formed. Additionally, the imine nitrogen atom is bonded at the Na atom which has the coordination number 4 in 1 . Additional coordination of the furfuryl oxygen atom results in the coordination number five for the sodium atom in 2 . In 3 which is also a tetramer, two Na₂O₂ units are connected via two imino‐ethanol bridges Na(1)‐N(=CH‐phenolat)‐CH₂CH₂‐OH‐Na(2A). The crystal structure analysis displays that 4 is an ionic compound consisting of two [(thf)₂Na(18‐crown‐6)]⁺ cations and the dinuclear dianion [Na ₂ (C) ₄ ] ^2? . Both 1 and 2 are carboxylation reagents which transfer CO₂ to 2‐fluoropropiophenone. 1 is more active than 2 , but 3 and 4 are inactive.     

Interaction of sodium cholate with dioctadecyldimethylammonium chloride vesicles in aqueous dispersion

Mixtures of dioctadecyldimethylammonium chloride (DODAC) cationic vesicle dispersions with aqueous micelle solutions of the anionic sodium cholate (NaC) were investigated by differential scanning calorimetry, DSC, turbidity and light scattering. Within the concentration range investigated (constant 1.0 mM DODAC and varying NaC concentration up to 4 mM), vesicle → micelle → aggregate transitions were observed. The turbidity of DODAC/NaC/water depends on time and NaC/DODAB molar concentration ratio R. At equilibrium, turbidity initially decreases smoothly with R to a low value (owing to the vesicle–micelle transition) when R = 0.5–0.8 and then increases steeply to a high value (owing to the micelle–aggregate transition) when R = 0.9–1.0. DSC thermograms exhibit a single and sharp endothermic peak at T_m ≈ 49 °C, characteristic of the melting temperature of neat DODAC vesicles in water. Upon addition of NaC, T_m initially decreases to vanish around R = 0.5, and the main transition peak broadens as R increases. For R > 1.0 two new (endo- and exothermic) peaks appear at lower temperatures indicating the formation of large aggregates since the dispersion is turbid. All samples are non-birefringent. Dynamic light scattering (DLS) data indicate that both DODAC and DODAC/NaC dispersions are highly polydisperse, and that the mean size of the aggregates tends to decrease as R increases.     

Liquid-liquid extraction of copper (I) and copper (II) as ion-paired complexes with acyclic 2-thienyl-containing polythioether and triphenylmethane dye anion

Three acyclic polythioethers containing 2-thienyl units at both ends were synthesized and the effect of substituent on the extraction of copper(II) was studied. The methyl groups in the terminal thiophene ring have imparted an appreciable degree of increase in the percent extraction of copper(II), while the introduction of chlorine atoms into the 2-thienyl unit resulted in the reverse effect. Among the counter dye anions examined, tetrabromophenolphthalein ethylester was the best one for copper(II) extraction. The composition of extracted species was evaluated to be 122 (Cu(II)/polythioether/dye anion). Quantitative extraction of copper(I) was attained as complexes with various triphenylmethane dyes, i.e., bromocresol green, bromothymol blue, bromo-phenol blue and pyrogallol red. Copper(I) in organic phase was completely back-extracted with 2 mole/l sulfuric acid containing 10% hydrogen peroxide.     

几种光敏剂光敏氧化效率的比较

<正> 光敏氧化效率是由敏化剂分子吸收光量子数及其产生单重态氧的量子产率决定的,这要求敏化剂的吸收光谱同光源的发射光谱很好地匹配。本文报道竹红菌甲素匹配高压钠灯有效地产生单重态氧,高效光敏氧化一系列具有不同反应活性的底物,成为单重态氧化学中一个新的光敏氧化体系。     

Wet carbon-based solid acid/NaNO_3 as a mild and efficient reagent for nitration of aromatic compound under solvent free conditions

Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO_3 under solvent free oxidation at room temperature.     

Zwei neue Metatitanate mit fünffach koordiniertem Titan: CsNaTiO3 und RbNaTiO3

Two New Metatitanates with Five-coordinated Titanium: CsNaTiO₃ and RbNaTiO₃ [1] The new oxides CsNaTiO₃ (I) and RbNaTiO₃ (II) are obtained by heating well grounded mixtures of the binary oxides in Ni-tubes as colourless platelike crystals. I: CsO_0.56, NaO_0.48 and TiO₂, Cs:Na:Ti = 1.1:1.1:1.0; 600°C, 61 d as well as CsO_0.97, NaO_0.48 and Ti₂O₃, Cs:Na:Ti = 1.5:3.0:1.0; 760°C, 27 d. II: RbO_0.52, NaO_0.48 and TiO₂, Rb:Na:Ti = 1.1:1.1:1.0; 750°C, 14 d as well as RbO_0.98, NaO_0.48 and Ti₂O₃, Rb:Na:Ti = 1.5:3.1:1.0; 760°C, 27 d. CsNaTiO₃ (orthorhombic, Cmcm) is nearly isostructural with KNaTiO₃ [2]; a = 601.4(1) pm, b = 1 120.3(1) pm, c = 563.4(1) pm (Guinier-Simon-Data, Z = 4). RbNaTiO₃ (monoclinic, C2/c) is isostructural with KNaTiO₃; a = 590.3(1) pm, b = 1 098.4(1) pm, c = 555.1(0) pm, β = 92.15° (Guinier-Simon-Data, Z = 4). Both structures are determined by using four-circle diffractometer data (CsNaTiO₃: Siemens AED2, 2 896I_o(hkl), MoKα , R = 2.4%, R_w = 2.3%; RbNaTiO₃: Philips PW 1 100, 2 743I_o(hkl), AgKα , R = 9.9%, R_w = 8.9%; additional data see text). The Madelung Part of Lattice Energy (MAPLE), Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR) and the Charge Distribution in Solids are calculated and discussed.     

Surface structures of adsorption layers of sodium hyaluronate and bovine serum albumin complexes on poly(γ-methyl-l-glutamate) film and their surface properties

Two-dimensional structures and characteristics of the complexes between sodium hyaluronate (NaHA) and bovine serum albumin (BSA) were studied by using a quartz crystal microbalance method and an atomic force microscope (AFM). NaHA did not adsorb on poly(-methyl-l-glutamate) (PMLG) film. On the other hand, the complexes adsorbed on it and the adsorption behaviors were found to be Langmuir types. With increasing weight ratio of BSA to NaHA, W _BSA, the adsorption constants K decreased and the saturated adsorption masses increased. The adsorbed complexes were spherical particles and at saturated adsorption states they covered compactly on the PMLG film. The mean diameters d _AFM estimated from the topographic images decreased from 70 to 54 nm with increasing W _BSA. The adhesion force F _ad and the frictional force F _f between the complex layers and the AFM tip were obtained by using the contact mode of the AFM. With increasing W _BSA, the values of F _ad decreased and the values of F _f increased. Compared with the frictional coefficient of the NaHA adsorption layer on the BSA monolayer, the values for the NaHA–BSA complex layer were found to be much higher.     

New method for the synthesis of β-bromostyrenes

A new stereoselective method was developed for the synthesis of -bromostyrenes (E/Z > 5/1) starting from hydrazones of aromatic aldehydes and bromoform in the presence of CuCl.     

CuCrAl和CuCrZr低温液相合成甲醇催化剂的研究

 用络合共沉淀法制备了CuCrAl和CuCrZr复合氧化物液相合成甲醇催化剂，其比表面分别达到119和116m2／g．在5．0～5．5MPa和383K条件下，分别用间歇式和流动式反应釜考察了催化剂的活性和稳定性．结果表明：CuCrAl和CuCrZr的活性均明显高于CuCr；CuCrAl的活性略高于CuCrZr，但甲酸甲酯（MF）的选择性明显低于CuCrZr；两者在12h内未见活性明显下降．甲醇钠在反应过程中部分转化为甲酸钠和NaOH．CuCrAl和CuCrZr有较高的氢解活性可抑制甲醇钠与MF生成甲酸钠，从而有较低的甲酸钠浓度．但是，Al2O3和ZrO2的酸性有利于甲醇脱水，引起甲醇钠水解生成NaOH．溶剂对CuCr基催化剂的活性和选择性有明显影响．对反应机理进行了讨论．