A simple and efficient solvent-free method was developed for the acetylation of alcohols, phenols and amines in excellent yields employing glycerol-based sulfonic acid (-SO3H) functionalized carbon catalyst under envi...A simple and efficient solvent-free method was developed for the acetylation of alcohols, phenols and amines in excellent yields employing glycerol-based sulfonic acid (-SO3H) functionalized carbon catalyst under environmentally benign reaction conditions. The salient features of this protocol are the short reaction time, ease of product isolation and reusability of the carbon catalyst.展开更多
Here,the effect of cerium and terbium ions substitution on structural,optical,dielectric,and electrical properties of Ca_(0.95)Y_(0.05)Fe_(12)O_(19)M-type hexaferrite prepared by solvent free method i.e.,auto co mbust...Here,the effect of cerium and terbium ions substitution on structural,optical,dielectric,and electrical properties of Ca_(0.95)Y_(0.05)Fe_(12)O_(19)M-type hexaferrite prepared by solvent free method i.e.,auto co mbustion method was reported.The X-ray diffraction technique was used for the structural examination.The hexagonal structure of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples is confirmed by X-ray diffraction(XRD)pattern analysis.The crystallite size of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)(x=0.0,0.5,1.0,1.5,and 2.0)samples ranges from 28.37 to 39.12 nm.The Fourier transform infrared spectroscopy(FTIR)spectra confirm the lattice vibration at the octahedral and tetrahedral sites.The strong emission peaks of 3.40 eV are seen at 364 nm.It is found that photoluminescence intensity reduces with Ce-Tb substitution,which is associated with a reduction in electron-hole recombination.In the temperature range of room temperature(23℃)to 200℃,the dielectric constant,dielectric loss,and AC conductivity were computed over a broad frequency range of 10^(2)-10^(5) Hz.Maxwell-Wagner's two-laye r model explains the frequency dependent dielectric behaviour of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples.The dielectric constant increases for the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples as the Ce-Tb concentration increases up to x=1.0,and with further increasing the Ce^(3+)and Tb^(3+)ions up to x=2.0 the dielectric constant decreases.All of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples exhibit non-Debye type relaxation behaviour,according to the impedance measurement.The substitution of Ce^(3+)and Tb^(3+)ions reduces the grain boundary density,resulting in the low values of the impedance at the grain boundaries.It is found that the multiple hopping conduction process is the main mechanism in the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)compounds.展开更多
文章采用732#强酸性阳离子交换树脂为催化剂,改进型无溶剂法合成高品质环氧大豆油。实验确定了高品质环氧大豆油的最佳合成条件:采用逐步加料,按m(大豆油):m(88%甲酸):m(30%双氧水):m(催化剂)=1:0.35:1.2:0.15的比例加料,加0.5 mL 1%的E...文章采用732#强酸性阳离子交换树脂为催化剂,改进型无溶剂法合成高品质环氧大豆油。实验确定了高品质环氧大豆油的最佳合成条件:采用逐步加料,按m(大豆油):m(88%甲酸):m(30%双氧水):m(催化剂)=1:0.35:1.2:0.15的比例加料,加0.5 mL 1%的EDTA稳定剂,制得的环氧大豆油品质较高。展开更多
文摘A simple and efficient solvent-free method was developed for the acetylation of alcohols, phenols and amines in excellent yields employing glycerol-based sulfonic acid (-SO3H) functionalized carbon catalyst under environmentally benign reaction conditions. The salient features of this protocol are the short reaction time, ease of product isolation and reusability of the carbon catalyst.
文摘Here,the effect of cerium and terbium ions substitution on structural,optical,dielectric,and electrical properties of Ca_(0.95)Y_(0.05)Fe_(12)O_(19)M-type hexaferrite prepared by solvent free method i.e.,auto co mbustion method was reported.The X-ray diffraction technique was used for the structural examination.The hexagonal structure of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples is confirmed by X-ray diffraction(XRD)pattern analysis.The crystallite size of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)(x=0.0,0.5,1.0,1.5,and 2.0)samples ranges from 28.37 to 39.12 nm.The Fourier transform infrared spectroscopy(FTIR)spectra confirm the lattice vibration at the octahedral and tetrahedral sites.The strong emission peaks of 3.40 eV are seen at 364 nm.It is found that photoluminescence intensity reduces with Ce-Tb substitution,which is associated with a reduction in electron-hole recombination.In the temperature range of room temperature(23℃)to 200℃,the dielectric constant,dielectric loss,and AC conductivity were computed over a broad frequency range of 10^(2)-10^(5) Hz.Maxwell-Wagner's two-laye r model explains the frequency dependent dielectric behaviour of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples.The dielectric constant increases for the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples as the Ce-Tb concentration increases up to x=1.0,and with further increasing the Ce^(3+)and Tb^(3+)ions up to x=2.0 the dielectric constant decreases.All of the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)samples exhibit non-Debye type relaxation behaviour,according to the impedance measurement.The substitution of Ce^(3+)and Tb^(3+)ions reduces the grain boundary density,resulting in the low values of the impedance at the grain boundaries.It is found that the multiple hopping conduction process is the main mechanism in the Ca_(0.95)Y_(0.05)Ce_(x)Tb_(x)Fe_(12-2x)O_(19)compounds.
文摘文章采用732#强酸性阳离子交换树脂为催化剂,改进型无溶剂法合成高品质环氧大豆油。实验确定了高品质环氧大豆油的最佳合成条件:采用逐步加料,按m(大豆油):m(88%甲酸):m(30%双氧水):m(催化剂)=1:0.35:1.2:0.15的比例加料,加0.5 mL 1%的EDTA稳定剂,制得的环氧大豆油品质较高。
