Catalysis Of Isopropanol By Acid-modified SPU-WL And ZSM-5 Molecular Sieves

Isopropyl alcohol is a very important chemical raw material,which can be used as solvent,extractant,chemical intermediate,gasoline additive and disinfectant,etc.It is widely used in the fields of medicine,paint,ink,fragrance and electronic industry.In China,the production and application market of isopropanol has huge development potential.At present,the direct hydration method of propylene is widely used,and its process is basically mature.The next research focus is to develop a new type of catalyst that is more efficient,stable,low cost and non-corrosive.Isopropyl ether is an important organic chemical raw material.It can be used as a solvent,an extractant,and can also be used to treat phenol-containing wastewater from gas plants.It can also be used as gasoline additive.It is used in petroleum,pharmaceutical,tobacco,environmental protection and other industries.widely.Isopropanol dehydration method is an earlier method for producing isopropyl ether.Its process is simple and its product quality is high,but it is less used in industry due to the limitation of traditional acid catalysts.Therefore,the development of new catalysts is crucial.Molecular sieve catalysts have regular and uniformly distributed pores,good shape selectivity,ion exchange,hydrothermal stability,and abundant acid sites.SPU-WL and ZSM-5 molecular sieves have good catalytic activity in the hydration reaction of propylene and the dehydration of isopropyl alcohol to isopropyl ether.In this paper,molecular sieves were used as catalysts to study the catalytic activity of molecular sieves for the two reactions of propylene hydration and isopropanol dehydration under laboratory conditions.By screening the types of molecular sieves and the ratio of silicon to aluminum,the molecular sieves with different silicon to aluminum ratios were subjected to XRD and SEM.Characterization,acid modification of the molecular sieve,XRD,SEM,TEM,N₂-TPD,NH₃-TPD,Py-IR and other characterizations of the acid-modified molecular sieve,and the catalytic reaction evaluation was carried out to prepare a highly active propylene hydration catalyst and isopropanol dehydration catalyst.The research is mainly as follows:（1）The catalytic reaction of several catalysts commonly used in industry was evaluated,and it was concluded that SPU-WL and ZSM-5 had higher catalytic activity and were more suitable for propylene hydration and isopropanol dehydration reactions.Then,the influence of the silicon-aluminum ratio of the two molecular sieves on the reaction activity was explored.It was found that the silicon-aluminum ratio of the molecular sieve had an impact on the pore size and acidity distribution of the molecular sieve.After the evaluation of the catalytic reaction,the SPU-WL molecular sieve was finally optimized and selected.and 60,the catalytic activity of ZSM-5 molecular sieve is higher when the Si/Al ratio is 80.（2）Boric acid and phosphotungstic acid impregnation were carried out on SPU-WL molecular sieves with a silicon-aluminum ratio of 25 and 60,and ZSM-5 molecular sieves with a silicon-aluminum ratio of 80,and the modified samples were subjected to XRD,SEM,TEM,N2-TPD,NH3-TPD,Py-IR and other characterization,found that acid modification does not change the molecular sieve framework structure,mainly to remove non-framework aluminum,and acid modification will affect the pore structure and acidity of molecular sieves.The reaction evaluation of the modified molecular sieve shows that the SPU-WL molecular sieve modified by 1%boric acid with a silicon-alumina ratio of 25 has a good catalytic effect on the dehydration of isopropanol.At a temperature of 180°C,the catalyst dosage is When the mass of isopropyl alcohol is 1:60,the conversion rate of isopropyl alcohol is 38.67%,and the selectivity of isopropyl ether is 85.14%.The stability of the catalyst has been stable at a high level,indicating that the catalyst has good stability.The SPU-WL molecular sieve modified by 1%phosphotungstic acid with a silicon-alumina ratio of 25 has a good catalytic effect on the hydration reaction of propylene.Compared with the industrial resin catalyst,the molecular sieve has better temperature resistance,and the molecular sieve catalyst still shows good catalytic activity and stability after the reaction is continuously carried out for 140 hours.