Methyl Chloride Synthesis Over Mesoporous Alumina Catalyst From Hydrochlorination Of Methanol

Methyl chloride（also known as Chloromethane,Monochloromethane）,used widely in chemical industry field,was used for chemical intermediates and chemical raw materials.The methyl chloride which can be used as intermediates for synthetizing downstream products,is more active than methane,and its acion is similar to methanol of the coal chemical industry.In recent years,the silicone industry has developed rapidly,which demand for methyl chloride increased,resulting in the consumption increasing of methyl chloride.The hydroxyl of methanol molecules is replaced by chlorine atoms to form methyl chloride,so the structure of methyl chloride is similar to the methanol.Because of the structural similarity,monochloromethane attracted more attention in the synthesis field of downstream products.he specific studies as follows:（1）Water,aluminum isopropoxide and sucrose respectively used as solvent,aluminum source and template,with sucrose-oriented,the aluminum isopropoxide hydrolysed and directionally assembled the mesoporous γ-Al₂O₃ catalyst,which is used as catalyst in the process of the synthesis of chloromethane from methanol hydrogen chloride.The results show that the catalyst was tested under the same conditions,compared with commercial γ-Al₂O₃,the catalyst performance of mesoporous γ-Al₂O₃ was increased three times.The conversion of methanol higher than that of commercial γ-Al₂O₃ catalyst,but the selectivity decreased slightly compared with mesoporous γ-Al₂O₃.BET analysis showed that mesoporous γ-Al₂O₃ catalyst prepared with sucrose had a larger specific surface area and concentrated pore distribution compared with commercial γ-Al₂O₃ catalyst.Pyridine infrared test results show that: the preparation of mesoporous γ-Al₂O₃ with source has a higher concentration of Lewis acid site on the mesoporous γ-Al₂O₃ catalyst than commercial γ-Al₂O₃.The large surface area and high concentration of Lewis acid active site performance for methanol and hydrogen chloride synthesis of methyl chloride catalyst.（2）The mesoporous γ-Al₂O₃ catalyst was modified by doped oxide and loaded metal chloride.The performance of modified catalyst prepared were studied.The results showed that the catalytic performance of the catalysts were decreased after doping oxide.The mesoporous γ-Al₂O₃ catalysts were prepared by modification of supported metal chlorides,which was dried directly.Drying and calcination were protected in air and hydrogen chloride respectively.The results show that the performance of catalyst calcination in the air is higher than that whithout calcination.Catalytic performance of catalyst calcination in HCl was higher than that of calcination in air.ZnCl2 and FeCl3 modified catalysts were calcined in air and HCl.The performance was improved significantly.The acidity of the catalyst surface was tested by pyridine infrared spectroscopy.The results showed that the concentration of Lewis acid sites on the catalysts modified by ZnCl2 and FeCl3 in air was higher than that supported nothing.Under the protection of hydrogen chloride,the concentration of Lewis acid active site on the catalyst surface is further enhanced.XPS and UV test showed that the ratio of Cl/Zn and Cl/Fe increased obviously when calcination in HCl atmosphere.It is indicated that increasing the atomic molar ratio of Cl/Zn and the molar ratio of Cl/Fe were benefited to enhance the performance of the catalyst.（3）Using absolute ethanol as solvent and isopropanol aluminum aluminum source,P123 as template,the control of aluminum ion directed self-assembly.Hydrochloric acid was added to inhibit the hydrolysis of aluminum isopropoxide.The hydrolysis rate of aluminum was controlled under the protection of nitrogen.Ordered mesoporous aluminum was prepared.The catalyst was used in the reaction for the synthesis of methyl chloride.The ordered mesoporous alumina catalyst activity tested was showed that the methyl chloride selectivity of ordered mesoporous alumina catalyst was improved than commercial alumina.The ordered mesoporous alumina was tested by small angle XRD showed that ordered mesoporous alumina was prepared.In order to further demonstrate the synthesis of ordered mesoporous γ-Al₂O₃,the TEM scanning was tested.By analyzing the TEM images,it was found that ordered mesoporous γ-Al₂O₃ was synthesized and presented as six square type.XRD analysis showed that the prepared Al₂O₃ was γ-Al₂O₃.