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Carbon capture and storage potential contribution to mitigate climate changeBaca, Angel Mario 20 September 2010 (has links)
Carbon Capture and Storage Potential Contribution to Mitigate Climate Change
By
Angel Mario Baca, M.A.
The University of Texas at Austin, 2009
Supervisor: Dr. Eric Bickel
This thesis evaluates the potential of the Carbon Capture and Storage technologies to mitigate climate change. This work emerged from the current debate regarding when CCS technologies are going to be ready in a commercial-scale, or whether they are going to be economically viable. Geologically, the world contains enough room for storing CO2 emissions, but it is still unsolved if leakage can be controlled and monitored. This research focuses on the development of an economic model to estimate the value of CCS.. This model uses equations from the DICE (Dynamic Integrated model on Climate and the Economy). Then, it estimates what change in temperature could occur, and computes the present value of damages to the economy. Moreover, emissions are simulated using the 40 scenario emissions from the Intergovernmental Panel on Climate Change. As the main conclusion of this model, CCS has to be deployed in almost in the entire number of fossil fuel plants around the world and has to be done in the next 30 years to see CCS having an impact, otherwise it would be relatively small and not worth it. Moreover, CCS technologies are part of the components to reduce climate change, but not the main one. It is required that governments, companies, and institution focus their efforts in working collaboratively towards the enforcement of new policies and development of more technologies. / text
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Synthesis of achiral and chiral CCC-NHC ligands and metal complexes for their catalytic applications in C-H functionalization of indoles with diazoacetates and benzoin condensationRawat, Maitreyee 10 May 2024 (has links) (PDF)
The N-heterocyclic carbene (NHCs) based pincer ligands field is still in its infancy after decades. They are known for their applications in organocatalysis, coordinating with transition metals and p-block elements, catalysis, and material chemistry. Among all NHCs, CCC-NHC-based on late-transition metal complexes were first developed by our group in 2005 with a unique metalation/transmetalation strategy. Our group also designed the chiral version of these CCC-NHC ligands to synthesize its metal complexes. However, their asymmetric catalytic applications were unknown. Wanting to expand on this work, we first successfully synthesized achiral CCC-NHC pincer complexes and their new catalytic application, as it is economically cheaper than directly working on developing a chiral version for catalysis. Then, different chiral CCC-NHC salts were synthesized based on different chiral arms and N-substituents on NHCs to modify their steric hindrance and electronic structure properties. These precursors were used for their enantioselective application in nucleophilic catalysis. In Chapter II, we will discuss the synthesis of the CCC-NHC pincer Ir (III) dimer complex and its first catalytic application in C−H functionalization of N-methylindoles with alpha-aryl-alpha-diazoacetates at the C-3. The best reaction conditions involve a combination of catalysts and substrates in a specific order. It resulted in the activation of the C-H bond with the formation of a new C-C bond to generate alpha-aryl-alpha-indolyl acetates with more than 99% conversion at room temperature without requiring any additives. The substrate scope and limitations of N-methyl indoles and diazoacetates were also explored. Chapter III will focus on a new modified synthetic route to synthesize and characterize chiral CCC-NHC chloride salts in a shorter synthetic route than the known one. The metalation/transmetalation of chiral CCC-NHC ligands with late transition metals and the initial attempt in asymmetric catalysis will be discussed in Chapter IV. Chapter, V, demonstrated nucleophilic catalysis of CCC-NHC precursors in benzoin condensation of aldehyde. The study started with the evaluation of fifteen different achiral bis-CCC-NHC salts based on triazole, imidazole, and benzimidazole. Further studies with chiral CCC-NHC salts also resulted in more than 99% conversion and 99% ee in benzoin products. The substrate scope of benzaldehyde with different substituents was also explored
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