过硼酸钠对于有机物的氧化作用的研究 II: 氧化偶氮硝基苯类的合成

作者曾报道过硼酸钠在醋酸溶液中可使芳氨基氧化成硝基;McKillop等曾报道将过硼酸钠用于官能团的氧化;Huestis曾报道在冰醋酸溶液中用过硼酸钠将芳胺氧化成偶氮苯。这些都表明过硼酸钠是一种优良的氧化剂,反应条件温和、选择性强、氧化剂本身。价廉且其还原后所生成的硼酸钠易于处理和排放。因此,值得深入研究其应用范围。我们在此则报道一组以过硼酸钠为氧化剂,使芳胺氧化成氧化偶氮苯的条件。最近我们发现,在乙醇-磷酸体系中,过硼酸钠能顺     

Spreading of dipalmitoyl phosphatidylcholine on the surface of sodium deoxycholate aqueous solution

The surface pressure vs. mokcular surface area relations for dipalmitoyl phosphatidylcholine (DPPC) insoluble monolayer and sodium deoxycholate (SDC) adsorbed monolayer,L and D1, respectively, were obtained from the analyses of surface tensions measured by the Wilhelmy glass plate. Also, D1 was obtained by a drop-weight method. Next, the surface pressure time course,(t), of the SDC aq. was measured by the Wilhelmy plate before and after DPPC was spread on the liquid surface. At DPPC spreading,(t) jumped to a maximum,, and decreased along an exponential curve. The values of with various surface amounts of DPPC and bulk concentrations of SDC were analyzed using a dual surface-region model. The model enabled the estimation of. For better fitting, modified relations were constructed in place of D1. The exponential decrease of(t) was also observed on the SDC adsorbed monolayer which was rapidly compressed by a moving barrier. The(t) relaxation rate constants of the SDC monolayers which were compressed by DPPC spreading and the moving barrier agreed with each other, suggesting a desorption of SDC from the surface.     

Thermal Emulsion Polymerization without any Conventional Initiators and Emulsifiers

Stable poly(styrene-co-sodium styrene sulfonate) (P(St-NaSS) nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. The obtained polymer nanoparticles have higher ξ potential, and the particle sizes have broad distribution. The stability of polymer particles originated from the addition of small amounts of ionic comonomer, NaSS, which can act as an emulsifier in somewhat. The monomer conversion could reach up to about 28 wt% in 48 h, and did not increase by further polymerization when higher polymerization temperature (120 ℃) was employed. This polymerization system may be give some further understand for mechanism of emulsion polymerization.     

Microcalorimetric studies on the non-competitive inhibition of bovine liver arginase

Two methods, e.g. initial rate method and thermokinetic reduced extent method were presented for studies on non-competitive inhibition. Arginase-catalyzed the hydrolysis of L-arginine toL-ornithine and urea and the inhibition of this reaction by sodium fluoride were studied in the absence and presence of exogenous of Mn²⁺at 37°C in 40 mM sodium barbiturate-hydrochloric acid buffer solution (pH 7.4). Both methods were successively used to determine the values of K₁. The advances and disadvantages of each method were compared in this paper. Exogenous Mn²⁺ could result in more sensitivity of arginase to F^-1. Since the inhibition of arginase by F^-1 depends on the pH values of the reaction system and behave as a non-competitive inhibition, it probably due to its small volume and high electronic density allow it access to the activity site of the enzyme and replaces of μ-OH₂ (or μ-OH) as the bridge ligand with Mn(II, II) cluster. However, further studies are necessary to determine the modes of interaction of F^-1 with bovine liver arginase. This revised version was published online in August 2006 with corrections to the Cover Date.     

水合硫酸氢钠催化合成2-乙氧基萘

以-水合硫酸氢钠为催化剂，β-萘酚和无水乙醇为原料合成了2-乙氧基萘。优化反应条件为：β-萘酚150mmol，无水乙醇900mmol，催化剂2．0g，回流反应时间5h，产率85．5％。     

Solvent extraction of sodium picrate with 15-crown-5 into carbon tetrachloride. The determination of the dimer-formation constant of a crown ether-univalent metal salt 1∶1∶1 complex

The theory is derived to determine the dimer-formation constant,K ₂, of a crown ethermetal salt 111 complex in organic solvents of low dielectric constant by solvent extraction. The theoretical predictions are verified experimentally by extraction of sodium picrate (NaA) with 15-crown-5 (15C5) into carbon tetrachloride. All the experiments were conducted at 25°C. The logK ₂ value of the Na(15C5)A complex in carbon tetrachloride has been determined to be 4.05±0.11. Moreover, the partition constant of the complex is calculated.     

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.     

Copper passivity and its breakdown in sodium bicarbonate solutions: A scanning electron microscopy and x-ray photoelectron and auger spectroscopy study

Effect of bicarbonate ions on the copper passivity and its local breakdown is studied by cyclic voltammetry, Auger spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy. Comparing data for solutions with various sodium bicarbonate concentrations shows copper to undergo pitting in 0.02 M NaHCO₃, whereas it remains stably passive in 0.10 M NaHCO₃. Independent studies suggest that carbonates play a protective role in stabilization of the oxide-hydroxide passive film on copper.     

Counterion Exchange Selectivity in Detergent–Polymer Aggregates

In aqueous solution, the interaction between sodium dodecyl sulfate (SDS) and poly(ethylene glycol) (PEG) results in the formation of small aggregates or clusters of SDS attached to the PEG polymer chain. Selectivity coefficients for exchange of two monovalent (N-methyl-4-cyanopyridinium cation and Tl⁺) and two divalent (methylviologen cation and Cu²⁺) counterions at the surface of SDS–PEG clusters, determined employing photophysical techniques, are similar, but not identical, to those for exchange at the surface of SDS micelles in the absence of PEG. The principal factor affecting ion exchange selectivity in SDS–PEG clusters does not appear to be aggregate size or surface charge density but rather the presence of poly(oxyethylene) subunits at the aggregate surface.