Studies in filter cake characterisation and modelling

Ph.DDOCTOR OF PHILOSOPH

Continuous flow intensification of ortho-lithiation at ambient conditions

Ortho-lithiation is an important class of reaction for the synthesis of regiospecifically substituted aromatics and it is an emerging method to prepare phthalides which are common pharmaceutically active compounds.1 This reaction is typically conducted in batch mode under cryogenic temperatures (-78 to -40 ℃)2 to tame the high reactivity of the organolithium intermediates. Scaling up batch cryogenic organolithiation chemistry has traditionally proven to be a significant challenge. This involves the need to handle large quantities of hazardous lithium reagents and excessive costs associated with cryogenic technology at scale. These challenges make ortho-lithiation reaction an ideal candidate in deploying continuous flow processing as a process intensification (PI) technique. Continuous flow processing offers several ‘green’ benefits in the case of ortho-lithiation reaction where the use of highly energy-intensive refrigeration to -78 ℃ may be avoided. This offers the prospect of considerable energy savings at industrial scale, leading to reduced greenhouse gas emissions. It can also achieve high purity product stream so the downstream processing steps may be simplified. This minimizes the amount of solvent used and increases productivity due to higher selectivity. In addition, the use of continuous flow processing lowers the risk of accidental releases arising from the lower inventories of hazardous material. Please click Additional Files below to see the full abstract

SHEAR STRESS AND STRESS RELAXATION EFFECTS ON PROPERTIES OF POLYETHERSULFONE HOLLOW FIBRE MEMBRANE

Master'sMASTER OF ENGINEERIN

Ultrathin high-performance hollow fiber membranes

US6015516Granted Paten

Screwing NaBH₄ through a Barrel without a Bang: A Kneaded Alternative to Fed-Batch Carbonyl Reductions

In this work the application of green chemistry principles such as process intensification and the replacement of reagents and solvents to more benign alternatives were coupled with the advantages of continuous manufacturing. The reduction of lipophilic aromatic aldehydes using an aqueous alkaline solution of NaBH₄ was achieved by means of mechanical shearing and kneading provided by a custom-made batch reactor at the lab scale and a twin screw extruder at the kilo scale. The process was run continuously for 17 min to yield 1.41 kg of product (89% purity). The benefits of running the process in a continuous manner instead a conventional fed-batch mode were discussed in terms of both environmental and economic factors

Sustainability Improvements through Catalyst Recycling in a Liquid–Liquid Batch and Continuous Phase Transfer Catalyzed Process

Phase transfer catalysis (PTC) is a potentially useful approach to processing but often uses environmentally problematic substances that typically end up in waste streams. The sustainability benefits of catalyst recovery from a third liquid layer in a PTC system were investigated for the O-alkylation of 3-phenyl-1-propanol. The system was operated in both the batch and the continuous modes. The formation of a third liquid phase and using it to recover catalyst reduces equipment footprint, product loss through the waste, and VOC emissions and improves energy efficiency compared to the equivalent process designed without the third liquid layer, but at the expense of higher costs, higher <i>E</i> factor, and lower volume efficiency. Overall, continuous phase transfer catalyst recycling is better than the equivalent batch process in volume efficiency, in-process inventory, mass efficiency, <i>E</i> factor, VOC emission, equipment footprint, and operating cost. However, the batch process with batch catalyst recycling is still more cost-effective in capital investment