Physicochemical activation

Norrington, F.E., Hyde, R.M., Willianrs, S.G., and Wootton, R. Physicochemical-activity relations in practice. 1. A rational and self-consistent data bank,/. Merf. Chem., 18(6) 604-607, 1975. 

Wootton, R., Cranfield, R., Sheppey, G.C. and Goodford, P.J. (1975). Physicochemical-Activity Relationships in Practice. 2. Rational Selection of Benzenoid Substituents. LMetLChem., 18, 607-613. 

Keeping this limitation in mind, it may be desirable to associate pressure with another mode of activation. This coupling will be called biactivation throughout this chapter. The aim of the chapter is to give the present status of the biactivation process considered as the combination of pressure (physical activation) with (a) chemical activation and (b) physicochemical activation. 

Optimization of chemical yields can also be achieved by physicochemical activation. It is meant as an activation mode resembling catalysis and involving physicochemical interactions between reactants and medium. The role of the solvent with respect to the course of organic reactions is of obvious importance. One of the first systematic studies reporting the kinetic effect is due to Menshutkin who determined rate constants for the addition of ethyl iodide to triethylamine [49]. This is a typical example of an ionogenic reaction in which the stability of the transition... 

One example of triactivation has been reported [77]. It consists of a combination of pressure, chemical activation and physicochemical activation. The most significative results are listed in Table 10.32. There are notable improvements when carrying out the reactions in ethylene glycol under 300 MPa in the presence of the lanthanide catalyst. However, the generality of such a triactivation method is not evident. 

Water migration due to hydraulic gradients in marine sediments can be induced by natural processes such as sediment accumulation proposed by Gibson (1958) or by placement of structures on or in the seafloor. Water movement through clays is a very complex phenomenon because of the physicochemical activity of the particles and the effect of the surroimding double layers on the clay particles. 

Sobarzo-Sanchez, E., Gonzalez, P., Valdes, C., Sanchez, G. Hidalgo, M. E. (2012). Applied biological and physicochemical activity of isoquinoline alkaloids oxoisoaporphine and boldine. Mo/ecw/ s, 77, 10958-10970. 

The present study aims at increasing the surface area of raw OFA through physicochemical treatment. The produced treated OFA is used for the adsorption of H2S. The success of such physicochemical activation in H2S removal is expected to lead to the utilization of OFA as low cost activated carbon for removal of toxic gases such as H2S. 

Bioassay-guided fractionation Bioassay-guided isolation involves the use of some well-defined protocol for the isolation of pure compounds with defined biological activity from a crude extract of a natural product which could be plant or animal parts or a cocktail of mixture. It involves step-by-step separation of fractions/constituents contained within the crude extracts or mixture based on their physicochemical activities and through assaying for biological activity. Several rounds of separation of fractions/constituents and bioassay may be required to finally identify pure molecular hit compound(s). 

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