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BMMs固載聯(lián)吡啶脯氨酸衍生物及其在Aldol反應(yīng)中的應(yīng)用和熒光性能

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【摘要】:非均相不對稱催化不僅具有產(chǎn)物易分離純化、催化劑可回收利用、適用于規(guī)模生產(chǎn)等多種優(yōu)點,還可利用載體與客體分子間特殊的電子效應(yīng)或空間限域效應(yīng)等性能提高催化反應(yīng)的催化活性和立體選擇性。介孔二氧化硅納米粒子因其具有較大的比表面積和孔容積以及可調(diào)節(jié)的介孔孔徑、高的機械強度、較好的熱穩(wěn)定性和易于修飾的內(nèi)外表面等特點,成為固載均相催化劑的優(yōu)良載體之一。其中雙模型介孔SiO_2(BMMs)是一種新型的介孔材料,它存在雙孔道結(jié)構(gòu):一種是3nm左右的蠕蟲狀一級孔,另一種是10-30 nm左右的球形顆粒堆積孔。獨特的雙孔道結(jié)構(gòu)可以使反應(yīng)物和產(chǎn)物分子在孔道中更好的反應(yīng)和擴(kuò)散,從而提高反應(yīng)效率。為此,本文以雙模型介孔SiO_2(BMMs)為無機載體,分別采用氫鍵和配位鍵方式實現(xiàn)了聯(lián)吡啶脯氨酸衍生物在無機多孔載體上的固載,同時制備出一系列非均相催化劑用于催化對硝基苯甲醛和環(huán)己酮的不對稱Aldol反應(yīng)。結(jié)合多種表征手段,開展了有機-無機雜化材料在多相不對稱催化中的性能研究。具體研究內(nèi)容和相關(guān)結(jié)果如下:1.以BMMs為無機載體,通過后嫁接法將不同含量的聯(lián)吡啶脯氨酸衍生物(2S,2’S)-N,N’-([2,2’-bipyridine]-3,3’-diyl)bis(pyrrolidine-2-carboxamide)(Z1)固載于BMMs表面,得到有機-無機納米復(fù)合材料Z1-BMMs-x(x=0.1-30,x代表Z1與BMMs的投入質(zhì)量比)。采用XRD、SEM、TEM、TG、FT-IR、UV-vis DRS、PL、元素分析等測試手段對樣品進(jìn)行了結(jié)構(gòu)分析和性能表征。同時考察了它們的熒光特性以及在不對稱Aldol反應(yīng)中的催化性能。結(jié)果表明有機分子Z1的引入沒有破壞介孔的結(jié)構(gòu)和穩(wěn)定性,且在BMMs表面分散度較高,并獲得較好的催化活性(產(chǎn)率高達(dá)80%,對映體選擇性高達(dá)85%),與均相催化劑Z1的催化效果相當(dāng)。2.為提高活性物種(Z1)在BMMs介孔表面的結(jié)構(gòu)穩(wěn)定性,將金屬離子(Co~(2+),Ni~(2+),Zn~(2+)和Cu~(2+))通過嫁接法負(fù)載于BMMs表面,并利用聯(lián)吡啶與金屬的配位絡(luò)合方式將有機分子(Z1)固載到BMMs介孔表面,從而得到非均相催化劑Z1MBMMs(M=Co,Ni,Zn,Cu)。以對硝基苯甲醛和環(huán)己酮的不對稱羥醛縮合反應(yīng)為模型反應(yīng),詳細(xì)考察和分析對比了Z1MBMMs和相對應(yīng)均相金屬配合物(MZ1)的催化性能。結(jié)果表明,Z1MBMMs的催化活性和立體選擇性均比相應(yīng)的均相催化劑有所提高。XRD、SEM、TEM、FT-IR、UV-vis DRS等表征結(jié)果說明BMMs的雙模型介孔結(jié)構(gòu)有利于活性物種(Z1)在介孔內(nèi)部均勻分布,以及反應(yīng)分子的吸附和擴(kuò)散。與氫鍵固載化方式相比,配位絡(luò)合作用力對活性物種Z1的固載更穩(wěn)定。3.上述非均相催化劑(Z1MBMMs)的循環(huán)催化效果表明,在進(jìn)行第一次循環(huán)反應(yīng)時保持了與首次反應(yīng)相當(dāng)?shù)漠a(chǎn)率和立體選擇性,但是第二次循環(huán)反應(yīng)的催化活性都有所降低。通過多種表征手段進(jìn)行初步分析非均相催化劑失活的原因如下:(1)由XRD,SEM,TEM,氮氣吸脫附等結(jié)果表明BMMs的穩(wěn)定性在反應(yīng)過程中受到影響,孔道結(jié)構(gòu)遭到破壞,經(jīng)過多次循環(huán)反應(yīng)后的催化劑不再保持BMMs獨特的雙模型孔道結(jié)構(gòu);(2)TG,UV-Vis DRS等結(jié)果表明反應(yīng)過程中有機物在介孔孔道表面堆積,活性位被覆蓋;(3)ICP結(jié)果表明反應(yīng)過程中載體表面金屬脫落,伴隨著Z1一起流失嚴(yán)重,這是造成催化劑失活的主要原因。
[Abstract]:The heterogeneous asymmetric catalysis not only has the advantages of easy separation and purification of the product, can be recycled by the catalyst, is suitable for large-scale production and the like, but also can improve the catalytic activity and the stereoselectivity of the catalytic reaction by utilizing the special electronic effect or the space limited domain effect between the carrier and the guest molecule. The mesoporous silica nano-particles are one of the excellent carriers of the solid-carrier homogeneous catalyst because of the characteristics of larger specific surface area and pore volume and adjustable mesoporous pore size, high mechanical strength, better thermal stability and easily modified inner and outer surfaces and the like. The two-model mesoporous SiO _ 2 (BMMs) is a novel mesoporous material. It has a double pore structure: a worm-like primary hole of about 3 nm, and the other is a spherical particle accumulation hole of about 10-30 nm. The unique dual-pore structure can enable better reaction and diffusion of reactants and product molecules in the pore canal, thereby improving the reaction efficiency. In this paper, by using double-model mesoporous SiO _ 2 (BMMs) as the inorganic carrier, the solid-loading of the co-dihydro-proline derivative on the inorganic porous carrier was realized by means of hydrogen bonding and coordination, and a series of heterogeneous catalysts were prepared to catalyze the asymmetric dol reaction of p-nitrobenzaldehyde and cyclohexanone. In this paper, the performance of organic-inorganic hybrid materials in heterogeneous asymmetric catalysis is studied by means of a variety of characterization methods. The specific research contents and relevant results are as follows:1. The organic-inorganic nanocomposite Z1-BMMs-x (x = 0.1-30, x represents the input mass ratio of Z1 and BMMs) was obtained by solid-loading BMMs as an inorganic carrier and by post-grafting. The samples were characterized by XRD, SEM, TEM, TG, FT-IR, UV-vis DRS, PL and element analysis. Their fluorescence properties and their catalytic properties in the asymmetric Chol reaction were also investigated. The results show that the introduction of the organic molecules Z1 does not destroy the structure and the stability of the mesopores, and the dispersity of the organic molecules Z1 is higher, and the better catalytic activity is obtained (the yield is as high as 80%, the enantioselectivity is as high as 85%), and the catalytic effect with the homogeneous catalyst Z1 is equivalent to that of the homogeneous catalyst Z1. in order to improve the structural stability of the active species (Z1) on the mesoporous surface of the BMMs, the metal ions (Co ~ (2 +), Ni ~ (2 +), Zn ~ (2 +) and Cu ~ (2 +)) are loaded on the surface of the BMMs by the grafting method, and the organic molecules (Z1) are fixed on the BMMs mesoporous surface by the coordination and complexing method of the coupling agent and the metal, So as to obtain the heterogeneous catalyst Z1MBMMs (M = Co, Ni, Zn, Cu). The catalytic properties of Z1MBMMs and the corresponding homogeneous metal complexes (MZ1) were compared and compared with the asymmetric aldol condensation reaction of p-nitrobenzaldehyde and cyclohexanone. The results show that the catalytic activity and stereoselectivity of Z1MBs are all higher than the corresponding homogeneous catalysts. The results of XRD, SEM, TEM, FT-IR, UV-vis DRS indicate that the two-model mesoporous structure of the BMMs is beneficial to the uniform distribution of the active species (Z1) in the mesoporous and the adsorption and diffusion of the reactive molecules. Compared with the method of hydrogen bonding, the binding force of the coordination complex is more stable to the immobilization of the active species Z1. The cyclic catalytic effect of the above-mentioned heterogeneous catalyst (Z1MBMMs) shows that the yield and the stereoselectivity comparable to the first reaction are maintained at the time of the first cyclic reaction, but the catalytic activity of the second cycle reaction is reduced. The causes of the deactivation of the heterogeneous catalyst by various means of characterization are as follows: (1) The results show that the stability of the BMMs is affected during the reaction, and the pore structure is destroyed. and (2) the TG, the UV-Vis DRS and the like indicate that the organic substances in the reaction process are accumulated on the surface of the mesoporous pore, and the active sites are covered; and (3) the ICP results indicate that the surface metal of the carrier in the reaction process is off, With the loss of Z1 together, this is the main cause of the catalyst deactivation.
【學(xué)位授予單位】:北京工業(yè)大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2016
【分類號】:O643.36

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