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Development of Pd & Au Supported Catalysts for Hydrodechlorination and A-3 coupling along with a Comparative Study of Cr, Co, & Zn Based Catalysts for Copolymerization

Title
Development of Pd & Au Supported Catalysts for Hydrodechlorination and A-3 coupling along with a Comparative Study of Cr, Co, & Zn Based Catalysts for Copolymerization
Author
사이라샤비르
Advisor(s)
Hakjune Rhee
Issue Date
2016-02
Publisher
한양대학교
Degree
Doctor
Abstract
The study relates to the development of organometallic catalysts with their applications to organic synthesis. Heterogeneous catalysts were developed, one of which involves Au(III) supported on Poly(NIPAM-co-4-VP). Poly(NIPAM-co-4-VP), is a thermoresponsive polymer synthesized by a combination of N-isopropylacrylamide (NIPAM) and 4-vinylpyridine (4-VP) in 1:1 feed ratio. It exhibits phase transition at low critical solution temperature (LCST) in water. Coordination of Au(III) with the polymer and reaction setup above LCST, combines polymer′s inverse solubility phenomenon with Au(III) catalytic powers. The combination is employed to catalyze a three component one-pot coupling reaction of aldehydes, amines and alkynes. Polymer works to aid the catalysis by a hydrophobic phase change at reaction temperature. The catalyst is tested successfully to be efficient enough under moderate conditions for a variety of substrates. Recyclability of the catalyst makes the process economical and environmentally friendly. Considering the dangers associated with polychlorinated arenes and polychlorinated biphenyls (PCBs), reductive hydrodechlorination is found to be efficient to detoxify these chemicals. The task has been accomplished successfully by the catalytic system comprising palladium nanoparticles supported on anion exchange resin AG X1-8. Palladium nanoparticles are introduced on resin by the reduction of Pd(II), held by resin-Pd(OAc)2 solution. Hydrodechlorination reaction is optimized at room temperature, making use of in-situ generated hydrogen from ammonium formate. Several repetitions of the reaction also does not limit the efficiency of the catalyst. Moreover, a demonstration of hydrodechlorination for a wide range of polychlorinated arenes and PCBs (Aroclor 1242, 1248, and 1254) is carried out effectively. In addition to the above mentioned heterogeneous catalysis, homogeneous catalysts based on Cr(III), Co(III), and Zn(II) are also studied. Carbon dioxide has long been considered as an environmental waste and utilization of carbon dioxide for the good is one of the most focused research area, lately. However, being stable, it is likely to react with high energy reagents like epoxides, promptly. Moreover, the product of copolymerization of epoxides and carbon dioxide are the highly demanded polycarbonates that are utilized for variety of industrial applications. In the current study, copolymerization of cyclohexene oxide and carbon dioxide was successfully demonstrated with 76% conversion to the products with polycyclohexene carbonate (pCHC) as the major products selectively using [Cr(babhq)OAcF] as catalyst. Among, similar homogeneous catalysts comprising of Cr(III), Co(III) and Zn(II) complexes, Cr(III) catalyst comprised of salen ligand is found to be most efficient for all the copolymerization reactions studied.|본 연구에서는 유기 합성 분야에서 응용할 수 있는 여러가지 유기 금속 촉매를 개발하였다. 먼저, Poly(NIPAM-co-4-VP)를 합성하였고, 이 고분자에 Au(Ⅲ) 금속을 담지시킨 불균일 촉매를 개발하였다. Poly(NIPAM-co-4-VP)는 온도감응성 고분자로, N-isopropylacrylamide (NIPAM)과 4-vinylpiridine (4-VP)를 1:1 비율로 합성하였다. 이 고분자는 LCST (Low Critical Solution Temperature) 거동을 보이며, Au(Ⅲ) 금속을 담지시킨 촉매 또한 LCST 이상의 온도에서 상전이가 일어난다. 이 촉매를 사용하여 aldehyde, amine과 alkyne의 one-pot 세분자 커플링 반응을 수행하였다. 이 고분자는 반응 온도에서 소수성으로 성질이 변하여 촉매반응을 도와주는 역할을 하게 된다. 이 촉매는 온화한 조건에서 다양한 출발문질들의 반응을 가능하게 하였다. 또한 이 촉매는 재사용이 가능하여 경제적이고 친환경적이다. 두번째로, polychlorinated arenes와 polychlorinated biphenyls (PCBs)의 위험성을 고려할 때, reductive hydrodechlorination은 이러한 물질들의 독성을 없애기 위한 효과적인 방법이다. 음이온교환수지 AG X1-8에 팔라듐을 나노크기로 담지시킨 촉매를 이용하여 이러한 반응을 효율적으로 수행하였다. Resin-Pd(OAc)2 용액에서 Pd(Ⅱ)를 환원시켜 나노크기의 팔라듐을 resin에 담지시켰다. Ammonium formate를 이용하여 in-situ 에서 수소를 만들어 상온에서 hydrodechlorination 반응을 수행하였다. 촉매를 재사용하여도 hydrodechlorination의 효율은 떨어지지 않았다. 또한, 다양한 polychlorinated arenes와 PCBs (Aroclor 1242, 1248, 그리고 1254)들의 hydrodechlorination을 수행하였다. 불균일 촉매뿐만 아니라 Cr(Ⅲ), Co(Ⅲ)와 Zn(Ⅱ) 금속을 이용한 균일촉매에 대한 연구도 진행하였다. 이산화탄소는 오래 전부터 환경 폐기물로 대두되었고, 최근 이산화탄소를 활용하는 방법에 대한 연구가 활발히 진행되고 있다. 이산화탄소의 반응성이 낮기 때문에 epoxide와 같은 고에너지 시약과 반응시켜야 하며, epoxide와 이산화탄소의 공중합반응으로 생성된 polycarbonate는 공업적으로 다양하게 활용될 수 있다. 이번 연구에서 [Cr(babhq)OAcF]를 촉매로 사용하여 epoxide와 CO2의 공중합반응을 성공적으로 수행하였고, polycyclohexencarbonate (pCHC)를 선택적으로 76%까지 얻을 수 있었다. Cr(Ⅲ), Co(Ⅲ)와 Zn(Ⅱ) complex를 포함하는 균일촉매들을 비교하였을 때, Salen 리간드를 포함한 Cr(Ⅲ) 촉매가 공중합반응에서 가장 효과적인 것으로 확인되었다.; The study relates to the development of organometallic catalysts with their applications to organic synthesis. Heterogeneous catalysts were developed, one of which involves Au(III) supported on Poly(NIPAM-co-4-VP). Poly(NIPAM-co-4-VP), is a thermoresponsive polymer synthesized by a combination of N-isopropylacrylamide (NIPAM) and 4-vinylpyridine (4-VP) in 1:1 feed ratio. It exhibits phase transition at low critical solution temperature (LCST) in water. Coordination of Au(III) with the polymer and reaction setup above LCST, combines polymer′s inverse solubility phenomenon with Au(III) catalytic powers. The combination is employed to catalyze a three component one-pot coupling reaction of aldehydes, amines and alkynes. Polymer works to aid the catalysis by a hydrophobic phase change at reaction temperature. The catalyst is tested successfully to be efficient enough under moderate conditions for a variety of substrates. Recyclability of the catalyst makes the process economical and environmentally friendly. Considering the dangers associated with polychlorinated arenes and polychlorinated biphenyls (PCBs), reductive hydrodechlorination is found to be efficient to detoxify these chemicals. The task has been accomplished successfully by the catalytic system comprising palladium nanoparticles supported on anion exchange resin AG X1-8. Palladium nanoparticles are introduced on resin by the reduction of Pd(II), held by resin-Pd(OAc)2 solution. Hydrodechlorination reaction is optimized at room temperature, making use of in-situ generated hydrogen from ammonium formate. Several repetitions of the reaction also does not limit the efficiency of the catalyst. Moreover, a demonstration of hydrodechlorination for a wide range of polychlorinated arenes and PCBs (Aroclor 1242, 1248, and 1254) is carried out effectively. In addition to the above mentioned heterogeneous catalysis, homogeneous catalysts based on Cr(III), Co(III), and Zn(II) are also studied. Carbon dioxide has long been considered as an environmental waste and utilization of carbon dioxide for the good is one of the most focused research area, lately. However, being stable, it is likely to react with high energy reagents like epoxides, promptly. Moreover, the product of copolymerization of epoxides and carbon dioxide are the highly demanded polycarbonates that are utilized for variety of industrial applications. In the current study, copolymerization of cyclohexene oxide and carbon dioxide was successfully demonstrated with 76% conversion to the products with polycyclohexene carbonate (pCHC) as the major products selectively using [Cr(babhq)OAcF] as catalyst. Among, similar homogeneous catalysts comprising of Cr(III), Co(III) and Zn(II) complexes, Cr(III) catalyst comprised of salen ligand is found to be most efficient for all the copolymerization reactions studied.
URI
https://repository.hanyang.ac.kr/handle/20.500.11754/126822http://hanyang.dcollection.net/common/orgView/200000427990
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GRADUATE SCHOOL[S](대학원) > APPLIED CHEMISTRY(응용화학과) > Theses (Ph.D.)
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