Green chemistry

Green chemistry, similar to sustainable chemistry or circular chemistry, is an area of chemistry and chemical engineering focused on the design of products and processes that minimize or eliminate the use and generation of hazardous substances. While environmental chemistry focuses on the effects of polluting chemicals on nature, green chemistry focuses on the environmental impact of chemistry, including lowering consumption of nonrenewable resources and technological approaches for preventing pollution. The overarching goals of green chemistry—namely, more resource-efficient and inherently safer design of molecules, materials, products, and processes—can be pursued in a wide range of contexts. History Green chemistry emerged from a variety of existing ideas and research efforts (such as atom economy and catalysis) in the period leading up to the 1990s, in the context of increasing attention to problems of chemical pollution and resource depletion. The development of green

Analysis of Fluid-Fluid Reaction Systems with Reactions in Both Phases

Adrien Calabria

Developing mathematical models for chemical reaction systems is essential for analysis, development, design, optimization and control of chemical, or biochemical industrial processes. Nowadays, more and more companies across the world have to deal with innovative concepts such as the Sustainable Chemistry (or "Green Chemistry"), which particularly require good knowledge of chemical reactions systems. Well-defined chemical operations involved in a process lead to its efficiency, energy saving and an improvement of the product quality. Furthermore, plants adopting this new philosophy minimize their byproduct production and pollutant formation. This master thesis works on developing a methodology for analysis and kinetic modeling of chemical reaction systems. In this present study, the case where chemical reactions take place in both phases of a heterogeneous biphasic fluid-fluid (F-F) reactor under isothermal conditions is considered. In order to model homogeneous or heterogeneous (F-F) chemical systems, a new approach called “Extent-based Incremental Identification” has recently been developed by the Laboratoire d’Automatique (EPFL). In contrast to the commonly used simultaneous approach, this extent-based incremental approach can compute parameters corresponding to reaction and mass transfer rates individually for each reaction and mass transfer laws, and also does not require prior postulation or knowledge of rate laws. This particular case is an extension of the dissertation done by Nirav Bhatt [1], which considers a heterogeneous chemical reaction system with reactions in one of the phases with steady state mass-transfer between the phases, and work done by Michael Amrhein [2], who developed a linear transformation that computed the extents of reaction from the numbers of moles in homogeneous reaction systems, with inlet and outlet streams. [1] Nirav Bhatt, EPFL Diss. n° 5028 (2011) [2] Amrhein et al., AIChE J. 56 (2010), 2873-2886

2013

Towards a Composite Benchmark Method for the Aqueous Solvation Free Energies of Organic Compounds

Daniel David Sadowsky

Water is ubiquitous in the biosphere, and the difficulty of rigorously treating the effects of aqueous solvation currently limits the widespread use of computational methods in many areas of environmental chemistry. We propose an approach to benchmark calculations of aqueous free energies of solvation based on molecular dynamics simulation which is derived from first principles, statistical mechanically complete, and systematically improvable. The approach partitions the solvation free energy into the free energies of solvent density change, solvent cavity organization, and solvent-solute interaction, each of which is computed from first principles. A composite approach is considered for the calculation of the contributions of quantum nuclear effects to solvation free energies and the contributions of electron correlation and relativistic effects to solvent-solute interactions.

2015

Analysis of Fluid-Fluid Reaction Systems with Reactions in Both Phases

Adrien Calabria

2013

Less toxic chemistry: the keys to substitution

Analysis of Fluid-Fluid Reaction Systems with Reactions in Both Phases

Towards a Composite Benchmark Method for the Aqueous Solvation Free Energies of Organic Compounds

Analysis of Fluid-Fluid Reaction Systems with Reactions in Both Phases

Towards a Composite Benchmark Method for the Aqueous Solvation Free Energies of Organic Compounds

Less toxic chemistry: the keys to substitution