Remarkably Fast and Mild Solvent-Free Conversion of Epoxides into Thiocyanohydrins Using Mukaiyama Reagent

Abstract

A mild and operationally simple method for the synthesis of thiocyanohydrins is described. Mukaiyama reagent is used as an effective reagent for the solvent-free conversion of epoxides into their corresponding thiocyanohydrins. The reactions were completed in <5 min to give thiocyanohydrins with perfect regioselectivity and isolated yields.     

RANDOM APPROXIMATION OF AN ADDITIVE FUNCTIONAL EQUATION OF m-APPOLLONIUS TYPE

In this paper,using the fixed-point and direct methods,we prove the HyersUlam stability of the following m-Appolonius type functional equation:∑mi=1 f(z-xi)=mf(z-1/m2∑mi=1xi)-1/m∑1≤i相似文献   

Structure and electronic properties of native and defected gallium nitride nanotubes

Structure and electronic properties of GaN nanotubes (GaNNTs) are investigated by using ab initio density functional theory. By full optimization, the optimized structures (bond-lengths and angles between them) of zigzag GaNNTs (n,0) and armchair GaNNTs (n,n) (4<n<11) are calculated. The difference between nitrogen ring diameter and gallium ring diameter (buckling distance) and semiconducting energy gap in term of diameter for zigzag and armchair GaNNTs have also been calculated. We found that buckling distance decreases by increasing nanotube diameter. Furthermore, we have investigated the effects of nitrogen and gallium vacancies on structure and electronic properties of zigzag GaNNT (5,0) using spin dependent density functional theory. By calculating the formation energy, we found that N vacancy in GaNNT (5,0) is more favorable than Ga vacancy. The nitrogen vacancy in zigzag GaNNT induces a 1.0μB magnetization and makes a polarized structure. We have shown that in polarized GaNNT a flat band near the Fermi energy splits to occupied spin up and unoccupied spin down levels.     

Study of optical properties in a cubic quantum dot

In this paper, the effect of hydrostatic pressure on both the intersubband optical absorption coefficients and the refractive index changes is studied for typical GaAs/Al _x  Ga_1?x As cubic quantum dot. We use analytical expressions for the linear and third-order nonlinear intersubband absorption coefficients and refractive index changes obtained by the compact-density matrix formalism. The linear, third-order nonlinear, and total intersubband absorption coefficients and refractive index changes are calculated at different pressures as a function of the photon energy with known values of box length (L), the incident optical intensity (I), and Al concentration (x). According to the results obtained from the present work, we have found that the pressure plays an important role in the intersubband optical absorption coefficient and refractive index changes in a cubic quantum dot.     

Phosphine-free conversion of alcohols into alkyl thiocyanates using trichloroisocyanuric acid/NH4SCN

A convenient and efficient phosphine-free procedure for the one-pot conversion of primary,secondary and tertiary alcohols into the corresponding alkyl thiocyanates or alkyl isothiocyanates is described using trichloroisocyanuric acid/NHUSCN.     

Highly selective oxidation of alcohols using MnO2/TiO2-ZrO2 as a novel heterogeneous catalyst

MnO₂/TiO₂-ZrO₂, which was synthesized by the adsorption method, demonstrated very high catalytic activity in the selective oxidation of benzyl alcohols to benzaldehydes with excellent yields and selectivity in short reaction times. The physical and chemical properties of MnO₂/TiO₂-ZrO₂ were investigated by XRD, XRF, BET, FT-IR and SEM techniques. The influence of the catalyst support (SBA-15, ZSM-5, TiO₂-ZrO₂ and Y), type of metal oxide supported, method of loading and amount of manganese nitrate loading have been thoroughly investigated. Moreover, the catalyst has shown excellent reusability in the process.     

Catalytic oxidation of urazoles and bis-urazoles to their corresponding triazolinediones using aluminium nitrate and a catalytic amount of silica sulfuric acid

Abstract  

A simple and efficient catalytic oxidation of urazoles and a bis-urazole to the corresponding triazolinediones by treatment with Al(NO₃)₃.9H₂O in the presence of a catalytic amount of silica sulfuric acid is described. A good range of urazole derivatives was selectively oxidized in CH₂Cl₂ at room temperature in good to excellent yields.     

Some properties of algebras of real-valued measurable functions

Measures and measurable functions are used primarily as tools for carrying out various calculations to increase our knowledge. We learn how to combine them in various ways by studying real analysis; a very useful subject on which very much has been written. In this paper, we regard measurable functions as algebras of real-valued functions (or equivalence classes of them) on a set or topological space under point-wise addition, multiplication, or lattice operations and our techniques resemble closely those used to study algebras of continuous functions. This is done by examining a number of explicit examples including Borel and Lebesgue measures and measurable functions.     

APPROXIMATION OF A CAUCHY-JENSEN ADDITIVE FUNCTIONAL EQUATION IN NON-ARCHIMEDEAN NORMED SPACES＊

Using the fixed point and direct methods,we prove the Hyers-Ulam stability of the following Cauchy-Jensen additive functional equation 2f p i=1 xi + q j=1 yj + 2 d k=1 zk 2 = p i=1 f(xi) + q j=1 f(yj) + 2 d k=1 f(zk),where p,q,d are integers greater than 1,in non-Archimedean normed spaces.