An efficient and environmentally benign procedure for the catalytic esterification of salicylic acid with aliphatic alcohols, CnH2n+1OH(n=1-5)and benzylic alcohols,RC6H4CH2OH(R=H,NO2,OCH3,Br,Cl,Me)was developed using ...An efficient and environmentally benign procedure for the catalytic esterification of salicylic acid with aliphatic alcohols, CnH2n+1OH(n=1-5)and benzylic alcohols,RC6H4CH2OH(R=H,NO2,OCH3,Br,Cl,Me)was developed using nano-SiO2-supported Preyssler heteropolyacid both under thermal conditions and microwave irradiation.Silica nanostructures were obtained through a sol-gel method and were characterized by transmission electron microscopy and powder X-ray diffraction.The effects of various parameters such as solvent type,molar ratio of substrates,Preyssler heteropolyacid loading on silica,catalyst amount,temperature,and reaction time were studied and the optimum conditions were obtained.It has been found that the catalyst with 30 wt%loading is highly active and shows high yields in esterification reactions.The use of nano-SiO2-supported Preyssler heteropolyacid coupled with microwave irradiation allows a solvent-free,rapid(3 min),and high-yielding reaction.This catalyst can be easily recovered and reused for many times without a significant loss in its activity.展开更多
The response surface method (RSM) was applied to study the liquid phase alkylation of benzene with 1-decene catalyzed by means of silica supported Preyssler heteropoly acid. A three step experimental design was develo...The response surface method (RSM) was applied to study the liquid phase alkylation of benzene with 1-decene catalyzed by means of silica supported Preyssler heteropoly acid. A three step experimental design was developed based on the central composite design (CCD). Catalyst loading, catalyst mass percent, and benzene to 1-decene molar ratio were used to optimize 1-decene conversion and linear alkylbenzene (LAB) yield. The results indicated that the quadratic model was significant for these two responses. The experimental results revealed that all variables had positive effect on 1-decene conversion. While increasing the catalyst loading tends to decrease LAB yield. Benzene to 1-decene molar ratio was found to be the most important factor that influenced LAB yield with a positive effect. Design expert software suggested several optimized solutions, among them the best choice was to use 31% catalyst loading, benzene to 1-decene molar ratio of 13, and catalyst percent of 3.6 wt% for obtaining 100% conversion and 88% LAB production yield.展开更多
Preyssler acid H14[NaP5W30O110] was used as reducing agent and stabilizer for the synthesis of gold nanoparticles by photolysis of Au(III)/Preyssler acid/propan-2-ol solution.Preyssler acid plays both the role of tran...Preyssler acid H14[NaP5W30O110] was used as reducing agent and stabilizer for the synthesis of gold nanoparticles by photolysis of Au(III)/Preyssler acid/propan-2-ol solution.Preyssler acid plays both the role of transferring electrons from propan-2-ol to Au(III) and stabilizing the nanoparticles.Propan-2-ol was used as sacrificial reagent for the photoformation of reduced Preyssler acid.Gold nanoparticles (Au NPs) were characterized by UV-Vis spectroscopy,transmission electron microscopy (TEM),and particle size distribution (PSD) measurements.The synthesized Au NPs had a uniform hexagonal morphology and their size was about 17 nm.The catalytic performance of these NPs for photodegradation of methyl orange (MeO) was investigated in aqueous solution.UV-Vis studies showed that Au NPs can catalyze photodegradation of this azo dye.The pseudo-first-order rate constants were also calculated for this reaction.展开更多
A novel magnetic acidic catalyst comprising Preyssler(H14[Na P5W30O110]) heteropoly acid support‐ed on silica coated nickel ferrite nanoparticles (Ni Fe2O4@Si O2) was prepared.The catalyst was characterized...A novel magnetic acidic catalyst comprising Preyssler(H14[Na P5W30O110]) heteropoly acid support‐ed on silica coated nickel ferrite nanoparticles (Ni Fe2O4@Si O2) was prepared.The catalyst was characterized by Fourier transform infrared,scanning electron microscopy,transmission electron microscopy,X‐ray diffraction,energy dispersive spectrum,VSM and particle size neasurement.Its catalytic activity was investigated for the synthesis of bis(dihydropyrimidinone)benzene and 3,4‐dihydropyrimidin‐2(1H)‐ones derivatives by the Biginelli reaction.With the catalyst,the reac‐tions occurred in less than 1 h with good to excellent yields.More importantly,the catalyst was easily separated from the reaction mixture by an external magnet and reused at least five times without degradation in the activity.展开更多
Preyssler-type heteropoly acid is introduced as a new,mild and efficient catalyst for protection of a variety of carbonyl compounds with 1,3-propane dithiol.
Sulfate-centered Preyssler-type polyoxometalate was used as the precursor to react with transition metal cations and organic ligand for constructing inorganic-organic hybrid materials {H[Ni2（H2O）4（Htrz）3]2（KSsW30...Sulfate-centered Preyssler-type polyoxometalate was used as the precursor to react with transition metal cations and organic ligand for constructing inorganic-organic hybrid materials {H[Ni2（H2O）4（Htrz）3]2（KSsW30O110）}·18H2O （trz = 1,2,4-triazole） （1）, which was characterized by single crystal X-ray diffraction analysis, energy-dispersive X-ray （EDX）, power X-ray diffraction （PXRD）, IR spectra and thermogravimetric （TG） analyses. In 1, the cylindrical vacancy of the inorganic crown-type anion （SsW30Ouo） captures a K^＋ ion resulting in the anion {KS5W3oO110）^9-, which was further connected by dimeric [Ni2（H2O）4（Htrz）3]2 metal-organic units into an one-dimensional （1D） chain-like structure. These 1D chains are further packed to form a three-dimensional （3D） supramolecular structure via Hbonding interactions. Here, the sulfate-centered Preyssler-typepolyoxometalate was firstly used to coordinate with transition metal cations and introduced into the inorganic-organic hybrid materials. Electrocatalytic study indicates that compound I exhibits good electrocatalytic activity toward reduction of H2O2 and NO2^-.展开更多
基金supported by Islamic Azad University,Mashhad Branch
文摘An efficient and environmentally benign procedure for the catalytic esterification of salicylic acid with aliphatic alcohols, CnH2n+1OH(n=1-5)and benzylic alcohols,RC6H4CH2OH(R=H,NO2,OCH3,Br,Cl,Me)was developed using nano-SiO2-supported Preyssler heteropolyacid both under thermal conditions and microwave irradiation.Silica nanostructures were obtained through a sol-gel method and were characterized by transmission electron microscopy and powder X-ray diffraction.The effects of various parameters such as solvent type,molar ratio of substrates,Preyssler heteropolyacid loading on silica,catalyst amount,temperature,and reaction time were studied and the optimum conditions were obtained.It has been found that the catalyst with 30 wt%loading is highly active and shows high yields in esterification reactions.The use of nano-SiO2-supported Preyssler heteropolyacid coupled with microwave irradiation allows a solvent-free,rapid(3 min),and high-yielding reaction.This catalyst can be easily recovered and reused for many times without a significant loss in its activity.
基金supported by the office of vice chancellor of research of Sharif University of Technology
文摘The response surface method (RSM) was applied to study the liquid phase alkylation of benzene with 1-decene catalyzed by means of silica supported Preyssler heteropoly acid. A three step experimental design was developed based on the central composite design (CCD). Catalyst loading, catalyst mass percent, and benzene to 1-decene molar ratio were used to optimize 1-decene conversion and linear alkylbenzene (LAB) yield. The results indicated that the quadratic model was significant for these two responses. The experimental results revealed that all variables had positive effect on 1-decene conversion. While increasing the catalyst loading tends to decrease LAB yield. Benzene to 1-decene molar ratio was found to be the most important factor that influenced LAB yield with a positive effect. Design expert software suggested several optimized solutions, among them the best choice was to use 31% catalyst loading, benzene to 1-decene molar ratio of 13, and catalyst percent of 3.6 wt% for obtaining 100% conversion and 88% LAB production yield.
基金supported by the Faculty of Engineering,Ferdowsi University of Mashhad,through the grant 13198
文摘Preyssler acid H14[NaP5W30O110] was used as reducing agent and stabilizer for the synthesis of gold nanoparticles by photolysis of Au(III)/Preyssler acid/propan-2-ol solution.Preyssler acid plays both the role of transferring electrons from propan-2-ol to Au(III) and stabilizing the nanoparticles.Propan-2-ol was used as sacrificial reagent for the photoformation of reduced Preyssler acid.Gold nanoparticles (Au NPs) were characterized by UV-Vis spectroscopy,transmission electron microscopy (TEM),and particle size distribution (PSD) measurements.The synthesized Au NPs had a uniform hexagonal morphology and their size was about 17 nm.The catalytic performance of these NPs for photodegradation of methyl orange (MeO) was investigated in aqueous solution.UV-Vis studies showed that Au NPs can catalyze photodegradation of this azo dye.The pseudo-first-order rate constants were also calculated for this reaction.
基金Ferdowsi and Islamic Azad University,Mashhad and Bandar Abbas Branches for financial support
文摘A novel magnetic acidic catalyst comprising Preyssler(H14[Na P5W30O110]) heteropoly acid support‐ed on silica coated nickel ferrite nanoparticles (Ni Fe2O4@Si O2) was prepared.The catalyst was characterized by Fourier transform infrared,scanning electron microscopy,transmission electron microscopy,X‐ray diffraction,energy dispersive spectrum,VSM and particle size neasurement.Its catalytic activity was investigated for the synthesis of bis(dihydropyrimidinone)benzene and 3,4‐dihydropyrimidin‐2(1H)‐ones derivatives by the Biginelli reaction.With the catalyst,the reac‐tions occurred in less than 1 h with good to excellent yields.More importantly,the catalyst was easily separated from the reaction mixture by an external magnet and reused at least five times without degradation in the activity.
文摘Preyssler-type heteropoly acid is introduced as a new,mild and efficient catalyst for protection of a variety of carbonyl compounds with 1,3-propane dithiol.
基金supported by the National Natural Science Foundation of China(No.21671032)Science and Technology Development Project Foundation of Jilin Province(No.20150520001JH)Science and Technology Research Foundation of the Thirteenth Five Years of Jilin Educational Committee(No.[2015]0056/JJKH20170605KJ)
文摘Sulfate-centered Preyssler-type polyoxometalate was used as the precursor to react with transition metal cations and organic ligand for constructing inorganic-organic hybrid materials {H[Ni2（H2O）4（Htrz）3]2（KSsW30O110）}·18H2O （trz = 1,2,4-triazole） （1）, which was characterized by single crystal X-ray diffraction analysis, energy-dispersive X-ray （EDX）, power X-ray diffraction （PXRD）, IR spectra and thermogravimetric （TG） analyses. In 1, the cylindrical vacancy of the inorganic crown-type anion （SsW30Ouo） captures a K^＋ ion resulting in the anion {KS5W3oO110）^9-, which was further connected by dimeric [Ni2（H2O）4（Htrz）3]2 metal-organic units into an one-dimensional （1D） chain-like structure. These 1D chains are further packed to form a three-dimensional （3D） supramolecular structure via Hbonding interactions. Here, the sulfate-centered Preyssler-typepolyoxometalate was firstly used to coordinate with transition metal cations and introduced into the inorganic-organic hybrid materials. Electrocatalytic study indicates that compound I exhibits good electrocatalytic activity toward reduction of H2O2 and NO2^-.
