本文關(guān)鍵詞： SPG乳化法 微膠囊負載鈀催化劑 碳-碳鍵形成　出處：《大連理工大學》2010年博士論文　論文類型：學位論文

【摘要】： 均相配位催化普遍具有反應(yīng)效率高、選擇性好、反應(yīng)條件溫和等優(yōu)點,在現(xiàn)代有機合成中占有重要的地位。但是,均相配位催化存在催化劑與產(chǎn)物難以分離、催化劑的回收和再利用困難等問題。為了解決這些問題,化學研究者們制備了負載型的過渡金屬催化劑,載體包括MCM-41、SBA-15等無機材料,以及有機高分子材料。這種方法雖然結(jié)合了多相催化與均相催化的優(yōu)點,有些催化劑表現(xiàn)出較高催化活性和選擇性,但由于金屬配合物多被負載于載體表面,且金屬—配體之間通常是通過較弱的配位鍵相結(jié)合,不可避免發(fā)生金屬活性物種向反應(yīng)液的溶出,使得催化活性降低；又由于這種負載型的催化劑不能較好地分散于反應(yīng)介質(zhì)中,影響了催化反應(yīng)效率,反應(yīng)時間通常比均相催化長。微膠囊負載過渡金屬配合物是一種新型的有機高分子負載型催化劑,可均勻分散于整個反應(yīng)介質(zhì)中,其膜內(nèi)配體的多點可配位作用,將更有效地阻止活性物種的流失。 本論文通過改進的方法,合成了4-二苯基膦苯乙烯(SDPP) 45單體,并利用SPG膜乳化技術(shù)制備了粒徑分布均勻、膜內(nèi)連有膦配體的微膠囊。最佳制備條件是：以含SDPP 1.20 g、20 wt%二乙烯基苯(DVB)和3.0 wt%的偶氮二異丁基腈(AIBN)的甲苯溶液作為分散相,以含1.0wt%的聚乙烯醇(PVA)和0.30 g／L的十二烷基硫酸鈉(SLS)的水溶液作為連續(xù)相,70℃下聚合反應(yīng)24 h。通過配體交換反應(yīng),獲得微膠囊膜內(nèi)負載鈀催化劑,并利用電感偶合等離子體發(fā)射光譜分析(ICP)測定了鈀含量。利用光學顯微鏡、掃描電子顯微鏡(SEM)和透射式電子顯微鏡(TEM)等對微膠囊及其負載鈀催化劑的結(jié)構(gòu)進行了表征。 通過微膠囊負載鈀催化的Suzuki交叉偶聯(lián)反應(yīng),考察了其催化性能及穩(wěn)定性。在最佳反應(yīng)條件下(1.0mol%Pd、鹵代芳烴0.25 mmol,芳基硼酸0.38 mmol, K2CO30.38 mmol, IPA 2mL,80℃),溴代芳烴與苯硼酸的反應(yīng)產(chǎn)率在80%以上,最高可達到99%。催化劑重復(fù)使用11次,4-溴苯乙酮與苯硼酸的反應(yīng)產(chǎn)率仍可達到96%。 研究結(jié)果表明,所制得的微膠囊負載鈀催化劑還能催化碘代芳烴與丙烯酸甲酯參與的Heck反應(yīng),反應(yīng)產(chǎn)率為51-99%。催化劑經(jīng)簡單過濾后,重復(fù)使用5次,依然保持活性基本不變,碘苯與丙烯酸甲酯的反應(yīng)產(chǎn)率保持在91%以上。 三相試驗研究結(jié)果表明,微膠囊負載鈀催化溴代芳烴與苯硼酸的Suzuki交叉偶聯(lián)反應(yīng),可認為催化反應(yīng)是在微膠囊內(nèi)部進行的,即反應(yīng)物通過微膠囊的膜孔道進入其內(nèi)部,在鈀催化劑的作用下,轉(zhuǎn)化成產(chǎn)物后,再經(jīng)膜孔道離開微膠囊。
[Abstract]:Homogeneous coordination catalysis has many advantages, such as high reaction efficiency, good selectivity, mild reaction conditions and so on, and plays an important role in modern organic synthesis. In order to solve these problems, the chemical researchers have prepared supported transition metal catalysts, which include inorganic materials such as MCM-41, SBA-15 and so on. Although this method combines the advantages of heterogeneous catalysis and homogeneous catalysis, some catalysts exhibit high catalytic activity and selectivity, but the metal complexes are mostly supported on the surface of the support. And the combination of metal and ligand is usually through the weak coordination bond, which inevitably leads to the dissolution of metal active species to the reaction solution, which results in the decrease of catalytic activity. Because this kind of supported catalyst can not be dispersed in the reaction medium well, it affects the efficiency of catalytic reaction. The reaction time is usually longer than that of homogeneous catalysis. Microencapsulated transition metal complexes are novel organic polymeric supported catalysts, which can be uniformly dispersed in the whole reaction medium. It will be more effective in preventing the loss of active species. In this paper, 4- diphenylphosphine styrene (SDPP) 45 monomer was synthesized by improved method, and the particle size distribution was uniform by SPG membrane emulsification technology. The optimum preparation conditions were as follows: toluene solution containing SDPP 1.20 g ~ (-1) W ~ (20) w ~ (t) divinylbenzene (DVB) and 3.0 wt ~ (%) azo-diisobutyl nitrile (AIBN) as dispersion phase. The aqueous solution containing 1.0 wt% polyvinyl alcohol (PVA) and 0.30 g / L sodium 12 alkyl sulfate (SLS) was polymerized at 70 鈩，

本文編號：1496247