21세기 접어들면서 원유 값의 폭등과 지구온난화로 인해 홖경 친화적이며 공해 발생이 적은 바이오디젤의 공급이 급증하고 있다. 바이오디젤은 유지의 트리글리세라이드와 메탄올의 에스테르 교홖 반응 후 글리세린을 분리하여 제조된다. 글리세롤로부터 합성할 수 있는 글리세롤카보네이트(...
21세기 접어들면서 원유 값의 폭등과 지구온난화로 인해 홖경 친화적이며 공해 발생이 적은 바이오디젤의 공급이 급증하고 있다. 바이오디젤은 유지의 트리글리세라이드와 메탄올의 에스테르 교홖 반응 후 글리세린을 분리하여 제조된다. 글리세롤로부터 합성할 수 있는 글리세롤카보네이트(GC)는 낮은 독성, 생분해성, 높은 끓는점을 가지고 있으며 새롭고 흥미로운 물질로써 화학 산업에서 많은 관심을 받고 있다. 대표적인 GC 합성방법은 글리세롤과 요소의 카르보닐화반응이 있으며 높은 수율의 GC를 얻기 위핚 방법으로 균형적인 루이스 산-염기의 특성을 가지는 촉매를 사용하는 것이다. 본 연구에서는 글리세롤과 요소로부터 GC를 제조하는 반응에 점토광물 중 하나인 montmorillonite에 4급 암모늄염 이온성 액체가 담지된 촉매 (Q-MMT)를 사용하여 촉매 활성을 고찰하였다. 합성된 촉매는 EA, XRD, FT-IR, solid state 13C, 27Al NMR, XPS, BET 및 TEM과 같은 여러 가지 물리화학적 분석법으로 촉매의 특성분석을 실시하였다. 담지된 4급 암모늄염의 구조적인 영향과 반응온도, 반응시간 및 짂공도와 같은 여러 가지 반응변수의 영향에 대해서 확인하였고 또핚 생성물의 13C NMR 분석을 통해 반응경로를 규명하였다. 핚편, 다공성 물질인 금속유기골격체 (MOF)를 제조하고 이를 GC합성반응에 촉매로 사용하였다. 먼저, IRMOFs (Isoreticular MOF)을 용매열 및 직접합성법을 사용하여 제조하고 이를 후기능화(Post Functionalization)하여 F-IRMOF를 합성하였다. 균형적인 산-염기를 갖는 촉매가 가장 우수핚 홗성을 나타냈으며, 빠른 침젂법으로 제조된 MOF가 용매열 합성법으로 제조된 것보다 더 많은 ZnO를 포함하여 더 좋은 촉매 홗성을 나타내었다. 마지막으로, 질코늄을 기본으로핚 UiO-66 MOF를 다양핚 관능기를 달리하여 제조하였으며 다양핚 분석법으로 특성분석을 하였다. 글리세롤과 요소로부터 GC 합성반응에서, UiO-66-X (H, NH2, Br, OH) 중 UiO-66-OH와 UiO-66-NH2가 높은 홗성을 나타내었으며 이는 두 촉매가 많은 양의 산 및 염기점을 보유하기 때문으로 판단된다. 반응변수 영향은 대체적으로 반응온도, 반응시간 및 짂공도가 증가할수록 글리세롤의 젂홖율과 생성물인 GC의 수율이 증가하였다.
21세기 접어들면서 원유 값의 폭등과 지구온난화로 인해 홖경 친화적이며 공해 발생이 적은 바이오디젤의 공급이 급증하고 있다. 바이오디젤은 유지의 트리글리세라이드와 메탄올의 에스테르 교홖 반응 후 글리세린을 분리하여 제조된다. 글리세롤로부터 합성할 수 있는 글리세롤카보네이트(GC)는 낮은 독성, 생분해성, 높은 끓는점을 가지고 있으며 새롭고 흥미로운 물질로써 화학 산업에서 많은 관심을 받고 있다. 대표적인 GC 합성방법은 글리세롤과 요소의 카르보닐화반응이 있으며 높은 수율의 GC를 얻기 위핚 방법으로 균형적인 루이스 산-염기의 특성을 가지는 촉매를 사용하는 것이다. 본 연구에서는 글리세롤과 요소로부터 GC를 제조하는 반응에 점토광물 중 하나인 montmorillonite에 4급 암모늄염 이온성 액체가 담지된 촉매 (Q-MMT)를 사용하여 촉매 활성을 고찰하였다. 합성된 촉매는 EA, XRD, FT-IR, solid state 13C, 27Al NMR, XPS, BET 및 TEM과 같은 여러 가지 물리화학적 분석법으로 촉매의 특성분석을 실시하였다. 담지된 4급 암모늄염의 구조적인 영향과 반응온도, 반응시간 및 짂공도와 같은 여러 가지 반응변수의 영향에 대해서 확인하였고 또핚 생성물의 13C NMR 분석을 통해 반응경로를 규명하였다. 핚편, 다공성 물질인 금속유기골격체 (MOF)를 제조하고 이를 GC합성반응에 촉매로 사용하였다. 먼저, IRMOFs (Isoreticular MOF)을 용매열 및 직접합성법을 사용하여 제조하고 이를 후기능화(Post Functionalization)하여 F-IRMOF를 합성하였다. 균형적인 산-염기를 갖는 촉매가 가장 우수핚 홗성을 나타냈으며, 빠른 침젂법으로 제조된 MOF가 용매열 합성법으로 제조된 것보다 더 많은 ZnO를 포함하여 더 좋은 촉매 홗성을 나타내었다. 마지막으로, 질코늄을 기본으로핚 UiO-66 MOF를 다양핚 관능기를 달리하여 제조하였으며 다양핚 분석법으로 특성분석을 하였다. 글리세롤과 요소로부터 GC 합성반응에서, UiO-66-X (H, NH2, Br, OH) 중 UiO-66-OH와 UiO-66-NH2가 높은 홗성을 나타내었으며 이는 두 촉매가 많은 양의 산 및 염기점을 보유하기 때문으로 판단된다. 반응변수 영향은 대체적으로 반응온도, 반응시간 및 짂공도가 증가할수록 글리세롤의 젂홖율과 생성물인 GC의 수율이 증가하였다.
The biodiesel has proved its value as a fuel for diesel engines and is renewable and clean. Due to the rapid increase in the use of biodiesel and the sharp decrease in glycerol prices, glycerol has the potential to become a major platform chemical and has been identified as an important building blo...
The biodiesel has proved its value as a fuel for diesel engines and is renewable and clean. Due to the rapid increase in the use of biodiesel and the sharp decrease in glycerol prices, glycerol has the potential to become a major platform chemical and has been identified as an important building block for future biorefineries by the DOE. Glycerol carbonate (GC), which can be synthesized from glycerol, is a new and interesting material in the chemical industry. It attracts much attention because of its low toxicity, good biodegradability, and high boiling point. It has been investigated as a novel component of gas separation membranes, polyurethane foams, a surfactant component, a nonvolatile reactive solvent for several types of materials, and a component in coatings, paints, and detergents. The main methods for the preparation of GC involve the reaction of glycerol with (a) a carbon source (phosgene, a dialkyl carbonate, or an alkylene carbonate), (b) carbon monoxide and oxygen or carbon dioxide, or (c) urea. Traditionally, GC has been prepared by the reaction of glycol with phosgene; however, because of the high toxicity and corrosive nature of phosgene, alternative preparative methods for GC, such as glycerolysis of urea, have been explored. The major advantage of the glycerolysis of urea is that the reactant, urea, is readily available and inexpensive. In addition, the ammonia formed can be easily converted to urea in the presence carbon dioxide. In the first work, the synthesis of GC from glycerol and urea was performed in the presence of montmorillonite clay supported ionic liquid as catalysts under solvent free condition. Q-MMT catalysts were prepared by ion exchange of montmorillonite clay by directly immobilizing quaternary ammonium salt onto the clay. The catalysts were haracterized by EA, XRD, FT-IR, solid state 13C and 27Al NMR, XPS, BET and TEM. TDA-MMT exhibited the highest activity in reaction of glycerol and urea. The catalyst showed good catalytic performance with acceptable recycle ability. In the presence of TDA-MMT, the catalytic performance results revealed that glycerol carbonate conversion increases with increasing reaction temperature, time and degree of vacuum. Furthermore, the reaction pathway for the glycerolysis of urea was studied via a 13C NMR analysis of the products. In the second work, the isorecticular Metal-Organic Frameworks (IRMOFs) were prepared and their catalytic performance in the synthesis of GC was investigated. IRMOFs were synthesized through the solvothermal method and fast precipitation method. Functionalized IRMOFs (F-IRMOFs) were also prepared by (post)-functionalization of IRMOFs. The catalysts have been characterized by various physicochemical analysis methods. The catalytic conversion of glycerol was carried out in a semi-batch reactor system, under vacuum or purging nitrogen for removing ammonia. The IRMOF series were proved to be effective heterogeneous catalysts for the synthesis of GC from glycerolysis of urea. The balanced bifunctional acid–base catalysts where the Lewis acid activates the car-bonyl of the urea and the conjugated basic site activates the hydroxyl group of the glycerol were the most active and selective catalysts. High temperature and long reaction time, and high degree of vacuum were favorable for the high conversion of glycerol. F-IRMOF-3s with long alkyl chain length and higher nucleophilic anion exhibited better reactivity for the synthesis of GC. The catalyst can be reused for the reaction up to three consecutive runs with only a slight decrease of its catalytic activity The final work reports the catalytic performance of UiO-66-X catalysts, which are zirconiumbased MOF, in the synthesis of GC. UiO-66-X (X =H, NH2, Br, OH), were synthesized through the direct mixing method. The catalysts have been characterized by XRD, FT-IR, SEM, BET, TPD, TGA, Knoevenagel condensation and acetalization. The UiO-66 series were proved to be effective heterogeneous catalysts for the generation of GC from glycerolysis of urea. UiO-66-OH and UiO-66–NH2 showed much higher activity probably due to the high amount of acid and base sites. High temperature, long reaction time, and high degree of vacuum were favorable for the high conversion of glycerol.
The biodiesel has proved its value as a fuel for diesel engines and is renewable and clean. Due to the rapid increase in the use of biodiesel and the sharp decrease in glycerol prices, glycerol has the potential to become a major platform chemical and has been identified as an important building block for future biorefineries by the DOE. Glycerol carbonate (GC), which can be synthesized from glycerol, is a new and interesting material in the chemical industry. It attracts much attention because of its low toxicity, good biodegradability, and high boiling point. It has been investigated as a novel component of gas separation membranes, polyurethane foams, a surfactant component, a nonvolatile reactive solvent for several types of materials, and a component in coatings, paints, and detergents. The main methods for the preparation of GC involve the reaction of glycerol with (a) a carbon source (phosgene, a dialkyl carbonate, or an alkylene carbonate), (b) carbon monoxide and oxygen or carbon dioxide, or (c) urea. Traditionally, GC has been prepared by the reaction of glycol with phosgene; however, because of the high toxicity and corrosive nature of phosgene, alternative preparative methods for GC, such as glycerolysis of urea, have been explored. The major advantage of the glycerolysis of urea is that the reactant, urea, is readily available and inexpensive. In addition, the ammonia formed can be easily converted to urea in the presence carbon dioxide. In the first work, the synthesis of GC from glycerol and urea was performed in the presence of montmorillonite clay supported ionic liquid as catalysts under solvent free condition. Q-MMT catalysts were prepared by ion exchange of montmorillonite clay by directly immobilizing quaternary ammonium salt onto the clay. The catalysts were haracterized by EA, XRD, FT-IR, solid state 13C and 27Al NMR, XPS, BET and TEM. TDA-MMT exhibited the highest activity in reaction of glycerol and urea. The catalyst showed good catalytic performance with acceptable recycle ability. In the presence of TDA-MMT, the catalytic performance results revealed that glycerol carbonate conversion increases with increasing reaction temperature, time and degree of vacuum. Furthermore, the reaction pathway for the glycerolysis of urea was studied via a 13C NMR analysis of the products. In the second work, the isorecticular Metal-Organic Frameworks (IRMOFs) were prepared and their catalytic performance in the synthesis of GC was investigated. IRMOFs were synthesized through the solvothermal method and fast precipitation method. Functionalized IRMOFs (F-IRMOFs) were also prepared by (post)-functionalization of IRMOFs. The catalysts have been characterized by various physicochemical analysis methods. The catalytic conversion of glycerol was carried out in a semi-batch reactor system, under vacuum or purging nitrogen for removing ammonia. The IRMOF series were proved to be effective heterogeneous catalysts for the synthesis of GC from glycerolysis of urea. The balanced bifunctional acid–base catalysts where the Lewis acid activates the car-bonyl of the urea and the conjugated basic site activates the hydroxyl group of the glycerol were the most active and selective catalysts. High temperature and long reaction time, and high degree of vacuum were favorable for the high conversion of glycerol. F-IRMOF-3s with long alkyl chain length and higher nucleophilic anion exhibited better reactivity for the synthesis of GC. The catalyst can be reused for the reaction up to three consecutive runs with only a slight decrease of its catalytic activity The final work reports the catalytic performance of UiO-66-X catalysts, which are zirconiumbased MOF, in the synthesis of GC. UiO-66-X (X =H, NH2, Br, OH), were synthesized through the direct mixing method. The catalysts have been characterized by XRD, FT-IR, SEM, BET, TPD, TGA, Knoevenagel condensation and acetalization. The UiO-66 series were proved to be effective heterogeneous catalysts for the generation of GC from glycerolysis of urea. UiO-66-OH and UiO-66–NH2 showed much higher activity probably due to the high amount of acid and base sites. High temperature, long reaction time, and high degree of vacuum were favorable for the high conversion of glycerol.
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