The Preparation Of Amorphous Ni-M/CNMS Catalyst And Its Catalytic Performance

CNMS?Chiral nematic mesoporous silicon?were prepared by self-assembly method,and chiral nematic liquid phase NCC with high specific area,unique optical properties and layered arrangement was took as template agent,which can accurately replicate left-handed spiral lamellar structure and liquid crystal characteristics.CNMS can provide more active sites for the loading who had large surface area,adjustable pore size and a large amount of silicon hydroxyl on the surface in order to combine inorganic metal particles and carriers better.Therefore,as a porous material with chiral characteristics,CNMS had many potential application value.Turpentine was a common secondary metabolite of plant,which was composed of a mixture of various terpenes,and mainly composed of?-pinene and?-pinene.The product of pinene hydrogenation was pinane,divided into cis-pinane and trans-pinane.In the industry,because of its better activity,cis-pinane ordinarily was more important than trans-pinane.Cis-pinane was considered as one of the significant raw materials of perfume industry,which was a important intermediate for linalool,hydrogen myrcenol,intermediates and other spices.Therefore,it was of great significant to research and prepare a catalyst with high activity and selectivity for turpentine deep processing and utilization.In this study,the preparation of amorphous Ni-M/CNMS catalyst was made by chemical reduction method loaded by CNMS that it had high specific surface area,good thermal stability and stable chemical properties to catalytic the hydrogenation of pinene and other major components of turpentine.The catalyst was characterized by different characterization methods to study on the morphology,structure and properties of the catalyst,and then comprehensively analysing it.The following several aspects were researched:?1?CNMS were prepared by self-assembly method,and chiral nematic liquid phase NCC was took as template agent.The suitable preparation conditions were investigated by single factor experiments at TOMS as silicon source,V?NCC?:V?TMOS?:V?APS?=500:30:1,p H?2.5,preparation temperature 40?,Stirring rate 200r·min^-1.?2?The hydrogenation products were analyzed by GC and GC-MS,the carrier and catalyst were characterized by XRD,BET,SEM-EDS,TEM,XPS and GT.CNMS who with Left-handed spiral structure were successfully synthesized by self-assembly method,with NCC as template agent.The material has multilayer mesoporous silicon structure,the outer surface is smooth and smooth,and the inner pore is porous.The average pore size 4.4nm,pore volume 0.59cm³/g and specific area 489.32m²/g.SEM,XPS and other analytical results show that amorphous Ni-B and amorphous Ni-P have been successfully loaded on CNMS,and the active components were evenly distributed,at the same time,the spherical metal particles were intact.?3?The preparation of Ni-B/CNMS amorphous catalyst was made by chemical reduction method and investigated optimal preparation conditions by single factor experiments and orthogonal tests at n?Ni?/n?B?=1:4,m?Ni?/m?CNMS?=1:3,the concentration of KBH₄ solution 0.3mol/l,the p H of KBH₄ solution 11.The?-pinene hydrogenation reaction conditions were optimized by single factor and orthogonal test,and these conditions were as follow:the reaction temperature was 120?,the reaction pressure was 4MPa,the reaction time is 210min,the dosage of catalyst is 5%of the amount of?-pinene.In these conditions there time reproducibility experiments were made.The results showed that the average conversion rate of?-pinene was99.57%,the average selectivity of cis-pinane was 97.28%and cis-pinane average yield was 96.86%,which also showed good reproducibility.Meanwhile,after being used for six times,the catalyst still had high activity.?4?The preparation of Ni-P/CNMS amorphous catalyst was made by chemical reduction method and investigated optimal preparation conditions by single factor experiments and orthogonal tests at m?CNMS?/m?Ni?=3,n?P?/n?Ni?=6,p H=7.85,preparation temperature 25.52?.The?-pinene hydrogenation reaction conditions were optimized by single factor and BBD response subsequently,and these conditions were as follow:the reaction time is 110min,the reaction pressure is 4.13MPa,the reaction temperature is 116?,the amount of catalyst is 6.78wt%.In these conditions there time reproducibility experiments were made.The results showed that the average conversion rate of?-pinene was 99.97%,the average selectivity of cis-pinane was 97.20%and cis-pinane average yield was 97.17%,which also showed good reproducibility.Meanwhile,after being used for six times,the catalyst still had high activity.?5?According to the above characterization results,there are several possible reasons to explain the deactivation of the catalyst.1)The active particles of the deactivation catalyst were seriously reunited with poor dispersion,and the metal particle spheres were damaged,meanwhile,the size of particles became large.2)The loss and oxidation of active components can be confirmed from XPS and other characterizations.In virtue of Ni valence state changing,the Ni⁰ content was importantly decreased and the proportion of Ni²⁺was increased by XPS spectrums,Ni⁰ was oxidized to Ni²⁺.