Showing papers by "Jason P. Hallett published in 2010"

An overview of CO2 capture technologies

Abstract: In this paper, three of the leading options for large scale CO2 capture are reviewed from a technical perspective. We consider solvent-based chemisorption techniques, carbonate looping technology, and the so-called oxyfuel process. For each technology option, we give an overview of the technology, listing advantages and disadvantages. Subsequently, a discussion of the level of technological maturity is presented, and we conclude by identifying current gaps in knowledge and suggest areas with significant scope for future work. We then discuss the suitability of using ionic liquids as novel, environmentally benign solvents with which to capture CO2. In addition, we consider alternatives to simply sequestering CO2—we present a discussion on the possibility of recycling captured CO2 and exploiting it as a C1 building block for the sustainable manufacture of polymers, fine chemicals, and liquid fuels. Finally, we present a discussion of relevant systems engineering methodologies in carbon capture system design.

An overview of CO 2 capture technologies

Abstract: In this paper, three of the leading options for large scale CO 2 capture are reviewed from a technical perspective. We consider solvent-based chemisorption techniques, carbonate looping technology and the so-called oxy-fuel process. For each technology option, we give an overview of the technology, listing advantages and disadvantages. Subsequently, a discussion of the level of technological maturity is presented, and we conclude by identifying current gaps in knowledge and suggest areas with significant scope for future work. We then investigate the suitability of using ionic liquids as novel, environmentally benign solvents with which to capture CO2. In addition, we consider alternatives to simply sequestering CO 2 we present a discussion on the possibility of recycling captured CO 2 and exploiting it as a C 1 building block for the sustainable manufacture of polymers, fine chemicals and liquid fuels. Finally, we present a discussion of relevant systems engineering methodologies in carbon capture system design.

Understanding siloxane functionalised ionic liquids

Abstract: In this paper we use ab initio theoretical methods in combination with experimental studies to investigate ion-pairs of the ionic liquid (IL) 1-methyl-3-pentamethyldisiloxymethylimidazolium chloride [(SiOSi)C1C1im]Cl, in order to deepen our understanding of the effects of functionalisation on an IL. In addition, we focus on the effect of the siloxy group on the viscosity. We establish that the ion-pairing energies of [(SiOSi)C1C1im]Cl are similar to those of 1-butyl-3-methylimidazolium chloride [C4C1im]Cl, because the anion interacts primarily with the imidazolium ring. A large range of ion-pair structural configurations is possible with different anion positions and chain orientations, contributing to a significant entropy. A H-bonded network forms, however the siloxy chain can shield the Cl− or key C–H sites thus introducing defects. Despite a significant increase in mass relative to [C4C1im]+, the combined barriers to rotation within the substituent chain are substantially reduced in [(SiOSi)C1C1im]+, this is primarily due to the flexibility of the siloxane linkage, and free rotation of the Si–Me methyl groups. The most important effect is a coupling of rotational motions within the chain which leads to dynamic inter-conversion of cation conformers, and facilitates movement of the anion around the cation, these will contribute to enhanced transport properties and a reduced viscosity. In addition, a longer charge arm is expected to enhance rotational and rotational-translational coupling in electric fields. Thus, for [(SiOSi)C1C1im]Cl ion-pair association is very similar to that of [C4C1im]Cl, but “dynamic” properties relating to torsional motion, a dynamic H-bonded network, and cation response to an external electric field are enhanced.

Coupling Reactions and Separation in Tunable Fluids: Phase Transfer-Catalysis and Acid-catalyzed Reactions

Abstract: The sections in this article are Introduction Phase Transfer Catalysis Background Phase Transfer Catalysis Quaternary Ammonium Salt-catalyzed Reactions PTC Separation and Recycling Using CO2 Near-critical Water Definition Properties Friedel–Crafts Chemistry in NCW Alkylcarbonic Acids Probing Alkylcarbonic Acids – Alkylcarbonic Acids with Diazodiphenylmethane (DDM) Reactions Using Alkylcarbonic Acids Ketal Formation Formation of Diazonium Salts Conclusion Keywords: supercritical fluid; coupling reactions; phase transfer catalysis; acid-catalyzed reactions; supercritical carbon dioxide