微反應(yīng)器內(nèi)沸石與ZIF-8膜的制備及其催化Knoevenagel縮合反應(yīng)性能研究
發(fā)布時間：2018-11-01 14:37
【摘要】：化工過程的微型化是近些年來化工技術(shù)領(lǐng)域的一大趨勢。作為微化工技術(shù)研究的核心,微反應(yīng)器依靠其強化傳質(zhì)傳熱、操作安全連續(xù)、容易工業(yè)放大等優(yōu)勢,在連續(xù)催化反應(yīng)和有機合成等領(lǐng)域獲得了廣泛的研究。而其中微反應(yīng)器內(nèi)催化劑的固定裝填問題及構(gòu)建高效穩(wěn)定的催化微反應(yīng)器是關(guān)鍵和難點之一。本文針對不同微反應(yīng)器的特點,通過不同的組裝策略和方法,在微反應(yīng)器內(nèi)制備厚度可調(diào)的沸石及ZIF-8膜層,構(gòu)建的膜微反應(yīng)器應(yīng)用于催化Knoevenagel縮合反應(yīng)評價其性能。主要研究內(nèi)容和結(jié)果如下：(1)針對毛細石英管微通道長徑比大的特點和常規(guī)靜態(tài)釜內(nèi)無法制備連續(xù)沸石膜層的難點,采用連續(xù)流動的合成策略制備了均勻連續(xù)的NaX沸石膜層。通過優(yōu)化合成條件,研究調(diào)控膜厚度的規(guī)律,結(jié)果表明：改變膜合成時間,可方便調(diào)控制備不同厚度的沸石膜層。該方法操作簡單,為毛細管內(nèi)制備沸石膜催化層或載體層并構(gòu)建膜微反應(yīng)器提供了新思路。NaX沸石膜經(jīng)Cs+交換形成CsNaX沸石膜催化微反應(yīng)器,應(yīng)用于催化苯甲醛與氰基乙酸乙酯的Knoevenagel縮合反應(yīng),在優(yōu)化條件下可獲得目標產(chǎn)物接近100%的收率。而且通過在反應(yīng)體系內(nèi)引入強吸水性的離子液體IL-BMIC作為水吸收劑,避免反應(yīng)產(chǎn)生的水對CsNaX催化層的中毒,可使膜催化微反應(yīng)器穩(wěn)定運行50 h以上而未見明顯失活,解決了沸石催化層的水熱失活問題。該過程可實現(xiàn)反應(yīng)的連續(xù)生產(chǎn),具有潛在的應(yīng)用開發(fā)前景。(2)以毛細石英管作為微通道反應(yīng)器,針對石英表面惰性、ZIF-8難成核生長成膜的問題,分別采用3-氨丙基三乙氧基硅烷(APTES)輔助和ZnO誘導(dǎo)成核生長兩種策略,研究優(yōu)化流動合成法制備均勻連續(xù)的ZIF-8膜。在優(yōu)化的合成條件下,膜層的厚度可通過膜合成時間來調(diào)控,為MOFs膜微反應(yīng)器的構(gòu)建提供了新途徑�；谑杷訸IF-8的催化功能,將構(gòu)建的ZIF-8膜微反應(yīng)器應(yīng)用于催化苯甲醛與氰基乙酸乙酯的Knoevenagel縮合反應(yīng),在溫和的反應(yīng)條件下可獲得目標產(chǎn)物接近100%的收率。與CsNaX沸石膜微反應(yīng)器相比,ZIF-8膜微反應(yīng)器表現(xiàn)出溫和條件下更高效的催化性能。(3)在多通道片式不銹鋼微反應(yīng)器內(nèi),采用常規(guī)合成釜內(nèi)靜態(tài)法制備了ZIF-8/NaA復(fù)合膜。針對不銹鋼微通道粗糙的表面形貌和大孔結(jié)構(gòu),首先采用晶種誘導(dǎo)法制備了均勻連續(xù)的NaA沸石層作為中間過渡層,填補載體的大孔使其表面趨于平整；然后通過化學(xué)生長制備ZnO層作為功能層誘導(dǎo)制備了連續(xù)均勻的ZIF-8膜催化層,ZIF-8沿著NaA沸石膜表面生長形成了ZIF-8/NaA復(fù)合膜結(jié)構(gòu)。將此ZIF-8/NaA復(fù)合膜微反應(yīng)器應(yīng)用于催化苯甲醛與氰基乙酸乙酯的Knoevenagel縮合反應(yīng),在溫和條件下獲得目標產(chǎn)物接近100%的收率,ZIF-8本身的疏水性可防止反應(yīng)產(chǎn)生的水中毒,催化活性至少保持50 h而未出現(xiàn)明顯失活,表現(xiàn)出優(yōu)良的催化活性和穩(wěn)定性。該過程為MOFs膜催化微反應(yīng)器的應(yīng)用提供了很好的開發(fā)前景。(4)在多通道的片式不銹鋼微反應(yīng)器內(nèi),基于不銹鋼的粗糙表面及導(dǎo)電性,采用物理沉積法和電化學(xué)方法沉積ZnO層作為載體修飾和誘導(dǎo)生長雙功能層制備了均勻連續(xù)的ZIF-8膜層。通過研究沉積不同形態(tài)ZnO層、膜合成時間、膜合成液濃度以及活化步驟對制備ZIF-8膜形貌的影響規(guī)律,獲得了一種在不銹鋼微通道內(nèi)直接制備ZIF-8膜的最佳工藝。將此構(gòu)建的ZIF-8膜催化微反應(yīng)器應(yīng)用于催化苯甲醛與氰基乙酸乙酯的Knoevenagel縮合反應(yīng),在溫和條件可獲得接近100%的目標產(chǎn)物收率,表現(xiàn)出優(yōu)良的催化活性和穩(wěn)定性。同ZIF-8/NaA復(fù)合膜微反應(yīng)器相比,該構(gòu)建方法表現(xiàn)出制備工藝更為簡便的優(yōu)勢。
[Abstract]:The miniaturization of chemical process is a trend in the field of chemical engineering in recent years. As the core of the micro-chemical technology research, the micro-reactor relies on its advantages such as strengthening mass transfer heat transfer, safe and continuous operation, easy industrial amplification and the like, and has been widely studied in the fields of continuous catalytic reaction and organic synthesis. The fixed loading problem of the catalyst in the micro-reactor and the construction of efficient and stable catalytic microreactors are one of the key and difficult problems. In view of the characteristics of different micro-reactors, through different assembly strategies and methods, the thickness-adjustable zeolite and ZIF-8 film layer were prepared in the micro-reactor, and the constructed membrane micro-reactor was used to evaluate the performance of the Knoevenagel condensation reaction. The main research contents and results are as follows: (1) According to the characteristics of large aspect ratio of capillary quartz tube microchannel and the difficulty in preparing continuous zeolite membrane layer in conventional static kettle, a uniform continuous NaX zeolite film layer is prepared by continuous flow synthesis strategy. By optimizing the synthesis conditions, the law of controlling the thickness of the membrane is studied. The results show that the formation time of the membrane is changed, and the zeolite membrane layer with different thickness can be conveniently regulated and controlled. The method is simple in operation, and provides a new idea for preparing a zeolite membrane catalytic layer or a carrier layer in a capillary tube and constructing a membrane micro-reactor. CsNaX zeolite membrane catalytic microreactor was formed by CsNaX zeolite membrane via Cs + exchange, which was used to catalyze the Knoevenagel condensation reaction of benzaldehyde with cyanoethyl acetate, and the yield of target product close to 100% could be obtained under optimized conditions. Moreover, by introducing strong water-absorbing ionic liquid IL-BMIC into the reaction system as the water absorbent, the poisoning of the water to the CsNaX catalytic layer caused by the reaction can be avoided, the membrane catalytic microreactor can stably run for more than 50 hours without obvious loss, and the problem of water heat loss of the zeolite catalytic layer is solved. The process can realize continuous production of reaction and has potential application and development prospect. (2) using a capillary quartz tube as a microchannel reactor, aiming at the problem that the quartz surface is inert and ZIF-8 is difficult to nucleate and grow, the three-aminopropyltrimethoxysilane (APTES) auxiliary and the ZnO-induced nucleation and growth strategies are respectively adopted, A uniform continuous ZIF-8 film was prepared by optimized flow synthesis. Under the optimized synthesis conditions, the thickness of the film layer can be regulated by the membrane synthesis time, and a new way is provided for the construction of the MOFs membrane micro-reactor. Based on the catalytic function of hydrophobic ZIF-8, the constructed ZIF-8 film micro-reactor was used to catalyze the Knoevenagel condensation reaction of benzaldehyde and cyanoethyl acetate, and the yield of the target product close to 100% can be obtained under mild reaction conditions. Compared with CsNaX zeolite membrane microreactors, ZIF-8 membrane microreactors exhibit more efficient catalytic performance under mild conditions. (3) ZIF-8/ NaA composite film was prepared by static method in a multi-channel sheet stainless steel microreactor. Aiming at the rough surface morphology and large pore structure of stainless steel micro-channel, the uniform continuous NaA zeolite layer is first prepared as the intermediate transition layer by using crystal seed crystal method, and the large hole of the carrier is filled to make its surface smooth. A continuous uniform ZIF-8 film catalytic layer was prepared by chemical growth of ZnO layer as functional layer, and ZIF-8/ NaA composite film structure was formed along the surface of NaA zeolite membrane. The ZIF-8/ NaA composite membrane micro-reactor is applied to the Knoevenagel condensation reaction of the catalytic benzaldehyde and the cyanide-based ethyl acetate, the yield of the target product close to 100% is obtained under mild conditions, the hydrophobicity of the ZIF-8 itself can prevent water poisoning caused by the reaction, the catalytic activity is maintained for at least 50h without obvious loss, exhibiting excellent catalytic activity and stability. The process provides a good development prospect for the application of the MOFs membrane catalytic microreactor. (4) In a multi-channel plate type stainless steel micro-reactor, a uniform continuous ZIF-8 film layer is prepared by using a physical deposition method and an electrochemical method to deposit a ZnO layer as a carrier modification and inducing growth double functional layer on the basis of the rough surface and the conductivity of the stainless steel. ZIF-8 film was prepared by direct preparation of ZIF-8 film in stainless steel microchannel by studying the influence of deposition on the morphology of ZIF-8 film by deposition of ZnO layer, film synthesis time, film composition concentration and activation step. The ZIF-8 membrane catalytic microreactor constructed here is used to catalyze the Knoevenagel condensation reaction of benzaldehyde and cyanoethyl acetate, and the yield of the target product close to 100% can be obtained under mild conditions, which shows excellent catalytic activity and stability. Compared with the ZIF-8/ NaA composite membrane micro-reactor, the construction method shows the advantages of simpler preparation process.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TQ052;O621.251
，
本文編號：2304220
[Abstract]:The miniaturization of chemical process is a trend in the field of chemical engineering in recent years. As the core of the micro-chemical technology research, the micro-reactor relies on its advantages such as strengthening mass transfer heat transfer, safe and continuous operation, easy industrial amplification and the like, and has been widely studied in the fields of continuous catalytic reaction and organic synthesis. The fixed loading problem of the catalyst in the micro-reactor and the construction of efficient and stable catalytic microreactors are one of the key and difficult problems. In view of the characteristics of different micro-reactors, through different assembly strategies and methods, the thickness-adjustable zeolite and ZIF-8 film layer were prepared in the micro-reactor, and the constructed membrane micro-reactor was used to evaluate the performance of the Knoevenagel condensation reaction. The main research contents and results are as follows: (1) According to the characteristics of large aspect ratio of capillary quartz tube microchannel and the difficulty in preparing continuous zeolite membrane layer in conventional static kettle, a uniform continuous NaX zeolite film layer is prepared by continuous flow synthesis strategy. By optimizing the synthesis conditions, the law of controlling the thickness of the membrane is studied. The results show that the formation time of the membrane is changed, and the zeolite membrane layer with different thickness can be conveniently regulated and controlled. The method is simple in operation, and provides a new idea for preparing a zeolite membrane catalytic layer or a carrier layer in a capillary tube and constructing a membrane micro-reactor. CsNaX zeolite membrane catalytic microreactor was formed by CsNaX zeolite membrane via Cs + exchange, which was used to catalyze the Knoevenagel condensation reaction of benzaldehyde with cyanoethyl acetate, and the yield of target product close to 100% could be obtained under optimized conditions. Moreover, by introducing strong water-absorbing ionic liquid IL-BMIC into the reaction system as the water absorbent, the poisoning of the water to the CsNaX catalytic layer caused by the reaction can be avoided, the membrane catalytic microreactor can stably run for more than 50 hours without obvious loss, and the problem of water heat loss of the zeolite catalytic layer is solved. The process can realize continuous production of reaction and has potential application and development prospect. (2) using a capillary quartz tube as a microchannel reactor, aiming at the problem that the quartz surface is inert and ZIF-8 is difficult to nucleate and grow, the three-aminopropyltrimethoxysilane (APTES) auxiliary and the ZnO-induced nucleation and growth strategies are respectively adopted, A uniform continuous ZIF-8 film was prepared by optimized flow synthesis. Under the optimized synthesis conditions, the thickness of the film layer can be regulated by the membrane synthesis time, and a new way is provided for the construction of the MOFs membrane micro-reactor. Based on the catalytic function of hydrophobic ZIF-8, the constructed ZIF-8 film micro-reactor was used to catalyze the Knoevenagel condensation reaction of benzaldehyde and cyanoethyl acetate, and the yield of the target product close to 100% can be obtained under mild reaction conditions. Compared with CsNaX zeolite membrane microreactors, ZIF-8 membrane microreactors exhibit more efficient catalytic performance under mild conditions. (3) ZIF-8/ NaA composite film was prepared by static method in a multi-channel sheet stainless steel microreactor. Aiming at the rough surface morphology and large pore structure of stainless steel micro-channel, the uniform continuous NaA zeolite layer is first prepared as the intermediate transition layer by using crystal seed crystal method, and the large hole of the carrier is filled to make its surface smooth. A continuous uniform ZIF-8 film catalytic layer was prepared by chemical growth of ZnO layer as functional layer, and ZIF-8/ NaA composite film structure was formed along the surface of NaA zeolite membrane. The ZIF-8/ NaA composite membrane micro-reactor is applied to the Knoevenagel condensation reaction of the catalytic benzaldehyde and the cyanide-based ethyl acetate, the yield of the target product close to 100% is obtained under mild conditions, the hydrophobicity of the ZIF-8 itself can prevent water poisoning caused by the reaction, the catalytic activity is maintained for at least 50h without obvious loss, exhibiting excellent catalytic activity and stability. The process provides a good development prospect for the application of the MOFs membrane catalytic microreactor. (4) In a multi-channel plate type stainless steel micro-reactor, a uniform continuous ZIF-8 film layer is prepared by using a physical deposition method and an electrochemical method to deposit a ZnO layer as a carrier modification and inducing growth double functional layer on the basis of the rough surface and the conductivity of the stainless steel. ZIF-8 film was prepared by direct preparation of ZIF-8 film in stainless steel microchannel by studying the influence of deposition on the morphology of ZIF-8 film by deposition of ZnO layer, film synthesis time, film composition concentration and activation step. The ZIF-8 membrane catalytic microreactor constructed here is used to catalyze the Knoevenagel condensation reaction of benzaldehyde and cyanoethyl acetate, and the yield of the target product close to 100% can be obtained under mild conditions, which shows excellent catalytic activity and stability. Compared with the ZIF-8/ NaA composite membrane micro-reactor, the construction method shows the advantages of simpler preparation process.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TQ052;O621.251
，
本文編號：2304220
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