【摘要】：手性多孔有機聚合物具有較高的穩(wěn)定性和催化活性,廣泛用于多相不對稱催化中.目前研究多集中在合成具有微孔結(jié)構(gòu)的聚合物,而少有具有多種孔道結(jié)構(gòu)(包含介孔和微孔)的聚合物的報道.之前我們報道了乙烯基修飾的BINAP配體,(S)-5,5’-divinyl-BINAP,將其與不同單體共聚后得到了一系列具有不同孔結(jié)構(gòu)的有機聚合物.其負載的Rh基催化劑在苯乙烯不對稱氫甲�；磻�,表現(xiàn)出比均相更高的產(chǎn)物對映體選擇性.本文采用不同的溴代步驟,合成了(S)-4,4’-divinyl-BINAP配體.將這兩種具有乙烯基官能團的手性配體按相同的摩爾比與二乙烯基苯(DVB)共聚,得到兩種不同的有機聚合物.負載[RuCl_2(benzene)]_2后,分別得到Ru/4-BINAP@POPs和Ru/5-BINAP@POPs-1.采用一鍋法合成了催化劑Ru/5-BINAP@POPs-2;以[RuCl_2(p-cyme)]_2和RuCl_3分別合成了Ru/5-BINAP@POPs-3和Ru/5-BINAP@POPs-4催化劑.N2物理吸附結(jié)果顯示,Ru/4-BINAP@POPs和Ru/5-BINAP@POPs-1催化劑具有相似的孔道結(jié)構(gòu);而采用一鍋法合成的Ru/5-BINAP@POPs-2催化劑的介孔孔徑較大.4-BINAP@POPs和5-BINAP@POPs聚合物的~(13)C核磁顯示,其均在145,137和128 ppm處有明顯的吸收峰,可歸結(jié)為萘環(huán)和苯環(huán)上的碳振動峰;在44.0 ppm處的峰歸屬為亞甲基上的碳振動峰;31P核磁顯示,在聚合物中P基本沒有被氧化.將所得到的Ru/POPs催化劑應用于乙酰乙酸甲酯的多相不對稱加氫反應中,Ru/5-BINAP@POPs-1催化劑具有與Ru/4-BINAP@POPs更快的反應速率.在相同反應條件下,催化劑活性大小為Ru/5-BINAP@POPs-1Ru/5-BINAP@POPs-3Ru/5-BINAP@POPs-4Ru/5-BINAP@POPs-2.另外Ru/5-BINAP@POPs-1催化劑對β-酮酸酯有著較好的底物適應性,且在釜式反應中可循環(huán)使用6次而活性基本不變.分析發(fā)現(xiàn),使用前后的催化劑均沒有明顯的Ru Ru鍵的存在.表明Ru金屬高度分散于催化劑上,且具有較高的穩(wěn)定性,金屬不易聚集,這也是其具有高活性和穩(wěn)定性的原因.
[Abstract]:Chiral porous organic polymers have high stability and catalytic activity and are widely used in heterogeneous asymmetric catalysis. At present, most of the studies are focused on the synthesis of polymers with microporous structure, but few reports of polymers with multiple pore structures (including mesoporous and microporous) have been reported. Previously, we reported the vinyl modified BINAP ligand, (S)-5, 5-divinylBINAP. they were copolymerized with different monomers and a series of organic polymers with different pore structures were prepared. Its supported Rh-based catalysts showed higher enantioselectivity than homogeneous catalysts in asymmetric hydroformylation of styrene. In this paper, (S)-4,4-divinylBINAP ligands were synthesized by different bromination steps. The two chiral ligands with vinyl functional groups were copolymerized with divinylbenzene (DVB) in the same molar ratio to give two different organic polymers. After loading [RuCl_2 (benzene)] _ 2, we get Ru/4-BINAP@POPs and Ru/5-BINAP@POPs-1., respectively. The catalyst Ru/5-BINAP@POPs-2; was synthesized by one pot method. Ru/5-BINAP@POPs-3 and Ru/5-BINAP@POPs-4 catalysts were synthesized with [RuCl_2 (p-cyme)] 2 and RuCl_3, respectively. Ru/4-BINAP@POPs and Ru/5-BINAP@POPs-1 catalysts have similar pore structure. However, the mesoporous pore size of the Ru/5-BINAP@POPs-2 catalyst synthesized by the one-pot method is larger than that of the 5-BINAP@POPs polymer and the ~ (13) C NMR shows that both of the catalysts have obvious absorption peaks at 145137 and 128 ppm. It can be attributed to the peak of carbon vibration on naphthalene ring and benzene ring. The peak at 44.0 ppm belongs to the carbon vibrational peak on methylene, and the 31p NMR shows that P has not been oxidized in the polymer. The obtained Ru/POPs catalyst was applied to the heterogeneous asymmetric hydrogenation of methyl acetoacetate. The Ru/5-BINAP@POPs-1 catalyst had a faster reaction rate with Ru/4-BINAP@POPs. Under the same reaction conditions, the activity of the catalyst is Ru/5-BINAP@POPs-1Ru/5-BINAP@POPs-3Ru/5-BINAP@POPs-4Ru/5-BINAP@POPs-2.. In addition, Ru/5-BINAP@POPs-1 catalyst has good substrate adaptability to 尾-keto ester, and it can be reused for 6 times in the tank reaction, but the activity is almost unchanged. It was found that there was no obvious Ru / Ru bond in the catalyst before and after the catalyst was used. The results show that the Ru metal is highly dispersed on the catalyst and has high stability, and the metal is not easy to aggregate, which is also the reason for its high activity and stability.
【作者單位】： 中國科學院大連化學物理研究所潔凈能源國家實驗室(籌);中國科學院大學;廈門大學化學系;中國科學院上海應用物理研究所上海同步輻射中心;中國科學院大連化學物理研究所催化基礎(chǔ)國家重點實驗室;
【基金】：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020400)~~
【分類號】：O621.251;O631

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