Preparation Of Palygorskite-loaded TS-1 And Its Application In The Synthesis Of Hydroxylamine Hydrochloride

Titanium-silicon molecular sieve?TS-1?is an environmentally friendly catalyst that conforms to the concept of"green chemistry".It is the most widely used high-efficiency catalyst at this stage.It is used in the synthesis of many organic compounds,especially the application of the catalytic oxidation reactions with H₂O₂.However,due to the high cost of raw materials,the production price is too expensive,and it is easy to disperse in the reaction materials.It is difficult to achieve effective solid-liquid separation.In order to improve the reuse rate of TS-1 and reduce the industrial production cost,the method of using the carrier to support the catalyst has drawn the author's attention.Palygorskite clay itself has special crystal structures and has many beneficial properties,which can be used as a catalyst.Therefore,this paper proposes to use palygorskite as a support to improve TS-1 synthesis from raw materials on the basis of traditional hydrothermal method,and it is used in the new joint production process of butanone oxime from butanone ammoximation and hydroxylamine hydrochloride from hydrolysis.The main research conclusions are as follows:1.TPABr instead of TPAOH was chosen as the template agent,and the silicon source and titanium source was changed respectively to conduct experiments.The research conclusions show that when using cheap TPABr as the template agent,adding n-butylamine as the base source system,the template and guiding action of the template agent can be promoted,and the resultant TS-1 crystal structure is better and the skeleton Titanium content is higher.At this time,the more economical JN-30 silica sol was adopted as the silicon source,which can further reduce the synthesis cost of TS-1,and simplify the experimental operation difficulty from the perspective of raw materials.2.Thermal analysis and acid modification of palygorskite were carried out to prepare Pal-TS-1 catalyst by in-situ loading.The research conclusions show that the palygorskite can maintain a layered structure at a calcination temperature of 600?and modified at 3mol/L hydrochloric acid at 70?for 3h;when the ratio of template agent:palygorskite is 8:3,The method that palygorskite is added first can promote the infiltration of titanium into the molecular sieve framework.At this time,the supported Pal-TS-1 catalyst has increased specific surface area and pore size,and improved catalytic performance.3.By using conversion rate of the butanone,selectivity and yield of the intermediate-butanone oxime to investigate the catalytic performance of palygorskite-supported Pal-TS-1.The research conclusions show that when the amount of feed material is butanone:hydrogen peroxide:ammonia=1:1.5:3,and the amount of supported catalyst is 7g/mol,and when continuous feeding mode was adopted for ammonia and hydrogen peroxide,the conversion rate of butanone can reach up to 98.4%,and selectivity for butanone oxime can reach 99.1%,and the yield for butanone oxime can reach 97.5%,the catalytic has good performance.After5 repeated experiments under the same conditions,the yield for butanone oxime remains 80.1%,the use of palygorskite to load the catalyst can effectively improve the reuse life.4.The preparation of butanone oxime from ammoximation was combined with hydroxylamine hydrochloride synthesis from hydrolysis to form a hydroxylamine hydrochloride production route using supported Pal-TS-1 molecular sieve as the catalyst,butanone as the raw material,and butanone oxime as the intermediate.By investigating the influence of acid concentration,reaction time and reaction temperature on the synthesis,the new process conditions were obtained:hydrochloric acid concentration is 6mol/L,reaction temperature is 105?,reaction time is 1 hour.Also,reaction distillation was carried out in a one-time feeding mode.Under this reaction condition,the yield of the target product hydroxylamine hydrochloride can reach 51.2%.This supported catalyst is a kind of green catalyst with wide prospects.