Hydroxylamine was found to be a mild reagent for conversion of arylboronic acids and their pinacolyl boronate esters into phenols. This procedure works on most arylboronic acids at room temperature, yielding phenols in moderate to good yields, and efficiently on arylboronates also yielding phenols in good yields. 相似文献
Molecular Diversity - Soluble epoxide hydrolase (sEH) enzyme plays an important role in the metabolism of endogenous chemical mediators, epoxyeicosatrienoic acids, which are involved in the... 相似文献
In polyelectrolyte-enhanced ultrafiltration (PEUF), a water-soluble anionic polyelectrolyte (in this study sodium polystyrene sulfonate or PSS) is added to hard water. The calcium and magnesium bind to the polymer which has a high enough molecular weight to be rejected by an ultrafiltration membrane. The permeate is softened water. Economically, the PSS needs to be recovered from the retentate for reuse. Three methods of recovery developed in this study were addition of NaCl, Na2CO3 or HCl to PEUF to regenerate PSS. Of the three PEUF processes considered, NaCl/PEUF as compared to Na2CO3/PEUF and HCl/PEUF provided the best scheme for the water softening process. PEUF is shown in this study to be competitive with lime softening at low flow rates. The PEUF process is more expensive than ion exchange for a stream containing only hardness ions. However, PEUF becomes nearly comparable with ion exchange for a stream containing hardness ions as well as bacteria, viruses and pyrogen. The cost comparisons are based on fully continuous operations and include treatment of waste streams from each process. 相似文献
This paper examines the robustness of the Welch test , the James test as well as Tan's Anova test (to be referred as Fβ test) for testing parallelism in k straight lines under heteroscedasticity and nonnormality. Results of Monte Carlo studies demonstrate the robustness of all tests with respect to departure from normality. Further, there is hardly any difference between these methods with respect to both power and size of the test. 相似文献
A one‐pot synthesis of functionalized benzo thiazine derivatives via a Cu‐catalyzed, multicomponent reaction of isocyanides, aniline, and heterocumulenes in acetonitrile at room temperature was developed. Transition metal‐catalyzed activation of C‐H bonds under mild copper‐catalytic reaction conditions, using simple and available starting materials, also obtaining a pure product with high yield without applying column chromatography are the major advantages of the applied method among the other ones used for this purpose. The structures are confirmed spectroscopically (1H‐ and 13C‐NMR, IR, and EI‐MS) and through elemental analyses. 相似文献
Quantum chemical calculations of undistorted poly(phenylene vinylene) chains at zero temperature exhibit chromophores which are delocalized over the whole polymer. We demonstrate with molecular dynamics simulations that chromophore localization in agreement with experiment can be obtained if the system is simulated at finite temperature. The dependence of the chromophore localization on the temperature is investigated. 相似文献
Free radical terpolymerization of (N,N)‐dimethylacrylamide, ethylene‐glycol‐dimethacrylate and N‐(p‐ or m‐ethyl‐phenyl)acrylamide leads to para‐ and meta‐ethyl‐phenyl‐modified hydrophilic polymer networks. Polymeric networks of different molar ratios are prepared in special molds to give water swellable disc‐ shaped samples. The swelling behavior in water and aqueous cyclodextrin (CD) solution of the obtained samples is described while a distinctive differentiation between the para‐ and meta‐ethyl‐phenyl containing networks in CD solution can be found.
The thermal expansion and magnetostriction of polycrystalline sample of the ErMn6Sn6 intermetallic compound with hexagonal HfFe6Ge6-type structure are investigated in the temperature range of 77 K to above 400 K. The thermal expansion measurement of the sample shows anomalous behavior around its TN=340 K. The isofield curves of volume magnetostriction also reveal anomalies at paramagnetic-antiferromagnetic and antiferromagnetic-ferrimagnetic phase transitions. In the antiferromagnetic state, the transition to ferrimagnetism can be induced by an applied magnetic field. The threshold field for the metamagnetic transition Hth increases from 0.18 T at 84 K to about 1 T around 220 K, and then decreases monotonously to TN. This behavior is well consistent with that observed earlier on magnetization curves attributed to exchange-related metamagnetic transition rather than the anisotropy-related one. Furthermore, the low Hth values suggest that the Mn-Mn coupling in ErMn6Sn6 is not so strong. The experimental results obtained are discussed in the framework of two-magnetic sublattice by bearing in mind the lattice parameter dependence of the interlayer Mn-Mn exchange interaction in this layered compound. From the temperature dependence of magnetostriction values and considering the magnetostriction relation of a hexagonal structure, we attempt to determine the signs of some of the magnetostriction constants for this compound. 相似文献