Double looped ring

Fluidized bed o Continuous stirred tank (Double) Loop Rotating ring disc Ui Stirred tank cascade g n> Stirred tank + tower Tower or tower cascade 1 Extruder Mixer + conveyor CPFR 1 u -P M H tJ Xi -p 2 rQ o Batch stirred tank + autoclave with gate paddle nuscer c Batch stirred tank + filter press BR u Batch stirred tank J Polymerization reactions... 

All these compounds were shown to be generally suitable hosts for the common incorporation of several cations, and they can complex identical or different metal ions (homo- or heteronuclear complexes, respectively). The symmetrical double loop compounds (38) (fe = 0, I = 0 fe = 1, I = 1 fe = 2, I = 2), (41) (R = H), and (43), which have oxygen donor sites only but which, however, gradually exhibit larger rings and donor numbers, readily form homobinuclear complexes with alkali/ alkaline-earth metal ions of suitable size. The asymmetrical diloop compounds... 

Compounds with cis double bonds in the side chain were in general found to be more potent and efficacious than their triple-bond congeners, both in in vivo and in in vitro functional assays [98, 106, 107]. QSAR models have been generated for the compounds with unsaturated [108] and l, l -dimethyl [96] side chains to determine more precisely the pharmacophoric requirements of the receptor. It is postulated that for optimum potency, the side chain must be of a suitable length and flexibility to have the ability to loop back so that its terminus is in proximity to the phenolic ring. The widely used, potency enhancing 1 - and 2 -methyl substituents would be expected to increase the tendency of the side chain to adopt a looped back, rather than an extended conformation. 

An aromatic compound, as typified by benzene, is cyclic with a closed loop of six electrons arising from three carbon-carbon double or triple bonds. Alternatively, they may arise from two double bonds and an unshared pair of electrons on a nitrogen atom of the ring. 

If the molecule has an unbroken loop of p orbitals, you will be able to draw at least two resonance structures that shift the double bonds around the loop, as we did for benzene. If any atom in the ring has four groups bound to it, then there can be no p orbital on that atom the pi loop is broken, and the ring cannot be aromatic. 

Consider the dynamics of an entangled ring polymer in an array of fixed obstacles [Fig. 9.40(a)]. The ring is not permanently trapped by the obstacles, but is able to diffuse. The ring does not have free ends and, therefore, classical snake-like reptation is not expected for it. An ideal untrapped ring polymer in an array of fixed topological obstacles is an unentangled loop formed by double-folded strands of Ne monomers each, similar to an arm of a star at the moment of complete retraction. 

Figure 13.3 Different loop reactor configurations (a) outlet flow is guided by a hollow ring and (b) outlet flow is guided by double walls [99].

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