Solvent chasing

To replace a lower-boiling solvent with a higher-boiling solvent on scale, usually the process stream is concentrated and the higher-boiling solvent is added to the concentrate. Then distillation is continued, with the second solvent chasing the first. 

Abbreviations rxn., reaction progress S.C., solvent chasing (by distillation) extn., extractions during work-up wash, washing a solid cake on a filter rxn. cond., reaction conditions cryst., crystallization conditions drying, drying isolated solid product. 

An important element of pollution prevention is the selection of environmentally benign chemical reactions, raw materials, solvents, and products. Over the past few years, significant progress has been made in this area. This chapter provides a brief overview of the recent advances in synthesizing green reactions and species. For more detailed discussion, the reader is referred to Anastas and lliamson (1996), Anastas and Farris (1994), and Chase (1995). 

You should be able to see that you have to be really careful in selecting those chaser, or pusher solvents mentioned. Sure, water (B.P. 100° C) is hot enough to chase ethyl alcohol (B.P. 78.3°C) from any column packing. Unfortunately, water and ethyl alcohol form an azeotrope and the technique won t work. (Please see Theory of Distillation, Chapter 28.)... 

Minimal number of repeated steps, for example, extractions Eacile solvent displacements that is, chase lower bp solvent with a higher bp solvent... 

A growing cadre of scientists is finding ways to reduce pollution, not by changing existing products, but by inventing cleaner ways to make them. Discusses some work in solvent-less chemistry. (Chase, 1995)... 

Shin C.Y., Chase G.G., Nanofibers from recycle waste expanded polystyrene using natural solvent, Polym. Bull, 55(3), 2005, 209-215. 

Bryantsev, V. S. Uddin, J. Giordani, V Walker, W. Addison, D. Chase, G. V., The Identification of Stable Solvents for Nonaqueous Rechargeable Li-Air Batteries. J. Electrochem. Soc. 2013,760, A160-A171. 

As Chase (1954) emphasized, all causes of possible irritation to the surface being tested, must be eliminated in order to avoid misinterpretation scratching of the animals, irritation caused by the method of depilation or by the solvent olive oil may be irritating in 5% of normal animals (Fisher and Cooke, 1958). 

Acid and solvent fume hoods bulkhead mounted in the BNC cleanroom. Bulkhead mounting equipment allows the separation of the operational side of the equipment (shown) from the maintenance side of the equipment, accessible through the cleanroom chase. 

Brenner M, Chase FL, Leydon AJ (1972) Gasket-forming solvent-based corn-positions containing styrene-butadiene block copolymers. U.S. Patent 3676386 Busch K, John S (1999) Liquid-crystal photonic-band-gap materials the tunable electromagnetic vacuum. Phys Rev Lett 83 967... 

Chase Jr GW, Thompson B. Accelerated solvent extraction of vitamin Ki in medical foods in conjunction with matrix solid-phase dispersion. J AOAC Int 2000 83(2) 407-10. 

Substrates were cleaned by rubbing with a paper towel under trichloroethylene, rinsing with fresh solvent, and after solvent evaporation the process was repeated with MIBK. Test specimens for Elastomers A, C, CC, D and DD were prepared by extruding beads onto 4 X 6 X 1/16 unanodized aluminum panels and pressing 1/4 in. x 4 mil unanodized aluminum or 1/4 in. x 10 mil series 500 cold-rolled steel ribbons into the beads. Separation of 1/16 in. was maintained between ribbons and panels with a chase. After 1 wk. cure, the elastomer bead was cut through to the panel along each side of the ribbon. Adhesion was measured by 180° peel, 2 in/min jaw separation rate, at ambient laboratory conditions. 

This work has a goal of improvement of PPy in stability. Energy dispersive X-ray spectroscopy and chronoamperometry were employed to chase movement of ions in the polymer in redox reaction. Mobility of ions involved on the redox reaction was correlated qualitatively with conformation of the dopants in the solvent used. 

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