Study On Preparation Of Anisole By Reaction Of Phenol With Dimethyl Carbonate Catalyzed By Composite Solid Base

CaO-based catalysts were found to be efficient heterogeneous catalysts for the methylation of dimethyl carbonate?DMC?with phenol in a closed high pressure reactor.The optimization experiences have been carried out to obtain best phenol conversion and the results showed that CaO catalyst modified with KCl had the best catalytic performance.When the reaction was carried out at temperature of 200?,with molar ratio of phenol and dimethyl carbonate of 1:2,3%dosage of KCl,15%dosage of KCl/CaO,9h,achieving 100%conversion of phenol and 95%selectivity towards anisole.The structure and properties of the materials were thoroughly characterized by Fourier transform infrared spectrometry?FTIR?,scanning electron microscopy?SEM?,and Brunauer-Emmett-Teller?BET?.It was found that the great relationship between surface basicity of catalyst and their catalytic performance for phenol conversion and anisole selectivity.CaO-based catalyst was prepared by impregnating potassium salt on CaO to develop a highly efficient heterogeneous catalyst for the synthesis of anisole?AN?from phenol and dimethyl carbonate.KF/CaO exhibited a high catalytic activity under moderate reaction conditions.A series of catalysts have been prepared and the highest yield of 97.48%AN was obtained at 200°C on CaO loaded with 15%KF after 10h.Various reaction parameters including KF loadings,the amount of catalyst and the calcination temperature on the catalytic activity were investigated.Scanning electron microscopy?SEM?,X-ray diffraction?XRD?,BET,CO₂-TPD and thermogravimetric?TG?were used to characterize the prepared catalyst.It was found that the high catalytic activity of CaO after modification with KF is associated with the structural aspects and the amount of basicity of the catalyst.Temperature programmed desorption of CO₂and XRD studies revealed the K₂O species,a strong basic site formed by the substitution of the Ca²⁺in CaO lattice by K⁺,might have great contribution for the high conversion of phenol and good selectivity of anisole.The solid base catalysts of different plant templates were prepared by impregnation method.The catalytic performance of the solid base catalysts for the preparation of anisole in the methylation reaction of phenol with dimethyl carbonate was investigated.The experimental results show that under the optimal reaction conditions,the yield and selectivity of methyl ether impregnated with radish as template are 93.95%and 93.68,respectively,which is higher than that of CaO.The SEM characterization results show that the ordered macroporous structure provides a good adhesion area for the reactants during the preparation process,so the catalytic effect is best.Synthesis of anisole with DMC and phenol over mixed oxide base catalysts that was prepared by the surfactant cetyltrimethylammonium bromide?CTAB?as colloidal template was studied.When the reaction was performed at atmospheric pressure and the presence of 4.5wt%of catalyst with respect to the reactants?DMC and phenol?at 200°C with a DMC/phenol molar ratio of 2 and reacting for 8 h,the phenol conversion and selectivity toward anisole were 87.66%and 99.38%respectively,and the yield of anisole was 87.11%.The catalysts were characterized and discovered that calcining temperature has a signification effect on the mesoporous Mg-Al hydrotalcite obtained by sol-gel method,while calcining temperature has a signification effect on the surface basicit and the surface structure of these catalysts.