Design And Research Of Catalytic Reactor With Switchable Function

Catalysis plays an indispensable role in modern industrial production.The use of catalysts can improve production efficiency and save energy,which is in line with the country’s needs for the development of green chemistry.We not only need to seek simple and efficient catalysts,but also need to adjust and control the catalysts to meet the complex requirements of multiple components and multiple steps involved in the chemical reaction process.Although the adjustment and control of the catalyst has practical significance,it is difficult to achieve such functions based on the catalyst itself,which is due the existing catalysts cannot control and adjust their own catalytic behavior.Inspired by the biological effects of nature,a series of temperature-sensitive switching intelligent catalytic reactors were designed to solve the problems encountered in the controllable and adjustable catalysis process.The smart catalytic reactors were used to reduce unnecessary side reactions and waste of raw materials,which can meet the complex catalytic needs in actual production.The research content can be summarized as the following aspects:In the first part of this article,a shape-memory polymer catalyst with a molecularly imprinted structure is designed as a catalytic reactor that can recognize switch switching.The shape memory polymer carrier is obtained by copolymerization of acrylic acid and octadecenic acid,which controls the switch of the catalyst.The imprinted structure with MB is constructed as the template to identify the catalytic substrate.The results of the study show that at low temperatures,the catalyst can recognize catalysis because of the existence of identifiable channels in the imprinted structure;at high temperatures,the imprinted structure is destroyed,so that the substrate cannot be recognized and catalyzed.The recognizable switching catalytic function of the polymer catalyst can be realized by changing temperature.Based on the above-mentioned shape memory polymers,two layers of polymers with opposite temperature-sensitive response behaviors were designed,endowing them the with ability of alternately switch catalysis.Based on the above-mentioned shape memory polymers,two layers of polymers with opposite temperature-sensitive response behaviors were designed,giving them the ability to alternately switch catalysis.The first layer of the polymer reactor is heat-shrinkable PNIPAm which is used to embed acidic active groups,and the second layer is a heat-expandable polymer with long-chain structure which is used to encapsulate active metal nanoparticles.The two layers of polymers are responsible for each alternate switching part of the catalytic process.The research results show that the phase transition temperature of the two layers is about 37 ℃.At low temperature,PNIPAm is exposed to hydrophilic acid sites,and only hydrolysis reaction occurs at this time;at high temperature,the long-chain branched "thawing" channel opens,and the substrate can contact the active metal nanoparticles and only the reduction reaction occurs.Therefore,the alternate switching catalysis of the substrate in the reactor can be realized through using the opposite temperature response of the two layers of polymer.Finally,two-layer polymer reactor is fabricated through further design and development of the above-mentioned polymer catalysts to achieve more refined catalysis requirements that can be switched in multiple stages.The two layers of polymers not only have opposite response temperatures but also different response temperatures.The first layer is heat-shrinkable PNIPAm which is used to encapsulate active metal nanoparticles with a phase transition temperature of 32 ℃;the second layer is a layer containing acidic active groups.with a phase transition temperature of37 ℃ When the temperature is lower than 32 ℃,only the reduction reaction will occur;when the temperature is higher than 37 ℃,only the hydrolysis reaction will occur;and when the temperature is 32～37 ℃,no catalytic reaction will occur.In this way,the two-layer polymer synergistic effect divides the temperature into multiple zones to realize multi-level switching catalysis.Through the above research content,this paper has realized the research of intelligent switching catalysis of catalyzed recognizable switching,alternate switching and multi-level switching,enriched the research content of intelligent switching catalysis and provided more solutions and ideas in this field,making the catalytic research develop to a more refined direction.