PET processing

Figure 8-100. Segmental downcomer design chart. Used by permission, Belles, W. L. Pet. Processing Feb. thru May (1956).

Bolles, W. L., Optimum Bubble-Cay Tray Design, Pet. Processing eh. through May 1956. 

Palmer, E. Y, How to Gatch Gompressor Troubles without Shutting Down the Engine, Pet. Processing, p. 884, June (1954). 

The facility of PET can be confirmed by a thermodynamic approach. For weakly interacting PET process, the associated free energy driving force of reaction (AG) can be estimated by the Rehm-Weller equation [20], expressed as... 

Ca2+ sensing by 1 can be understood by considering a PET process originating in the Ca2+-free tetracarboxylate receptor and the linearly fused tricyclic system. The rapidity of the process may be ascribed to the low oxidation potential of the electron rich alkoxyaniline donor and to the short distance of separation between the two transfer components. The minimal separation arranged by a virtual spacer of zero carbon atoms is worthy of note. A low level of luminescence is seen owing to the fast PET. 

The mechanistic basis of 3 and 4 is a double application of the argument used for the YES operation with 1. Each receptor in 3 is capable of launching a PET process if the lumophore is powered up by ultraviolet excitation. In other words, the fluorescence of the 9-cyanoanthracene unit is efficiently quenched by either the amine or the 1,2-dioxybenzene group within the benzo-15-crown-5 ether unit. These quenching processes are predictable from thermodynamic calculations or from related bimolecular quenching experiments in the literature. The small separation of the amine from the lumophore ensures rapid PET kinetics. On the other hand, the presence of four bonds between the benzo-15-crown-5 ether and the lumophore is probably responsible for the incomplete quenching seen between this pair. No information is yet available regarding possible folded conformations of 3. 

Each of these PET processes can be arrested upon ionic command. Provision of H+ at high enough... 

However, there is an important subtlety in 4. While amine receptor-anthracene lumophore pairs produce excellent PET based quenching, a benzo-15-crown-5 ether receptor is demonstrably incapable of transferring an electron to an excited anthracene lumophore unless the latter carries an electron withdrawing substituent. Then, what is the secret of 4 s success First, only one rapid PET process is... 

The PET process in the dyad is located in the normal region of the Marcus curve, while the back-electron transfer from Q0 to ZnPor+ is in the Marcus inverted region (Figure 6.27). 

In contrast to the -conjugated probe architecture utilizing an ICT process, the number of anion probes that rely on the fluorophore-spacer-receptor design and an active PET process is abundant [72], Again, anthracene and naphthalene... 

---