Preparation Of Nano Metal Catalysts For Oxidation Reactions

Oxidation reaction plays an important role in organic synthesis,and its products were widely used in all aspects of chemical industry.With the national attention to environmental protection,it is of great significance to study and develop environmental friendly oxidation catalysts.In this paper,according to the current needs in the field of energy and chemical industry,isobutylene oxidation and formic acid dehydrogenation were selected to represent aerobic oxidation and anaerobic oxidation reactions,respectively,and the catalytic effect of nano-catalysts on the oxidation reaction was studied..Due to the promotion of the use of ethanol gasoline in China,MTBE is prohibited as a gasoline additive,resulting in excess capacity of its raw material isobutylene.The process of preparing methyl methacrylate?MAL?using isobutylene as the starting material through selective catalytic oxidation,and MAL through oxidation and esterification to produce methyl methacrylate?MMA?becomes more attractive.The selective catalytic oxidation of isobutylene to MAL is a key step in the two-step production of MMA from isobutylene.In addition,as a kind of non renewable energy,the large-scale use of gasoline has caused serious damage to the ecological environment,so the search for clean renewable energy has become an important challenge for researchers.Hydrogen energy is considered as the most potential clean energy in the 21st century because of its non-toxic,by-product water and good combustion performance.However,the disadvantages of difficult storage and transportation hinder the popularization of hydrogen energy.Formic acid was thermodynamically stable,liquid at room temperature,environmental-friendly,and has a high hydrogen storage density?4.4 wt%?.It has become a hot spot in the research of liquid hydrogen storage materials.In this paper,the oxidation of isobutylene and the oxidative dehydrogenation of formic acid catalyzed by nano metallic materials were studied.?1?In this paper,a series of Mo based composite metal catalysts were synthesized by accelerating the stirring speed of catalyst preparation.The effects of different metal components and their proportions on the catalytic oxidation of isobutylene to MAL were investigated.Through the selection of catalyst composition,the best composition of the catalyst was Mo₁₂Bi_1.2Fe₃Co₈K_0.4.The reaction conditions were investigated systematically,such as reaction temperature,ratio of olefin to oxygen,space velocity and operation time,and the best reaction conditions were obtained.The experimental results show that at 320°C,the volume ratio of isobutylene to air is 1:10,the space velocity is 2000 h^-1,the conversion of isobutylene was 98.6%,the selectivity of MAL was 86.4%,and the yield of MAL was 85.2%.?2?In this paper,nano porous gold catalysts were prepared by dealloying method to study the oxidative dehydrogenation of pure formic acid.SEM and TEM characterization showed that it has a bicontinuous three-dimensional network structure with an average ligament size of about 30 nm.The molar ratio of formic acid to triethylamine,the kinds of amines,reaction temperature,the amount of catalyst and the repeatability were investigated.The results showed that when tetramethylethylenediamine was used as base,the molar ratio of formic acid to amines was 4:1,the temperature was 110°C,the amount of catalyst was 0.08mmol,the conversion of formic acid was 95%,and the TOF value was 132 h^-1.After 5 cycles,the activity of catalyst was not decreased.