Oligomers, liquid-like

The simulated and experimental variations of the end-of-run (i.e., 8 hr.) isomerization rates with density are compared in Figure 1. Details of the experiments are provided elsewhere [2, 3]. At subcritical densities, the extraction of coke precursors is insignificant. Hence, an increase in the concentration of the hexene and coke precursors (i.e., oligomers) leads to lower isomerization rates. At near-critical densities, the extraction of coke precursors becomes significant. Hence, the isomerization rate increases. Both the experimental and simulated rates show a decreasing trend when the density is increased from near-critical to supercritical values. This is attributed to pore-diffusion limitations as the fluid changes from gas-like to liquid-like. Above 2.0 pc, the isomerization rate increases with density as the ability of the reaction mixture to extract the coke precursors increases. 

These conjugated oligomers are likely to form organized molecular assemblies if coupled with suitable complementary structures. The dimers la and Ila-IId were made to react with various aromatic mono- and diamines in order to build mesogenic molecular structures capable of giving rise to thermotropic liquid ciystals ( ). When the dimer moiety was entirely furanic, no mesophase appeared, whereas the thiophenic and mixed moieties produced clear-cut nematic phases. 

In contrast to the polymers and copolymers of butadiene, the oligomers of aromatic olefins, like styrene, are not compatible with PVC. Oligomers of alkylated polystyrenes are a little better, especially in combination with other liquid plasticizers. Copolymers of styrene and isobutylene are not suitable for use with PVC. 

The term oligomer refers to a polymer-like material having only a few repeating units. The oligomeric phosphorus esters which are the subject of the present paper are generally viscous liquids having an average of two or more phosphate and/or phos-phonate ester units per molecule. 

Fuchigami and his coworkers employed [EMIM][OTf] for the electropolymeri-zation. They found that the polymerization of pyrrole in the ionic liquid proceeds much faster than that in conventional media like aqueous and acetonitrile solutions containing 0.1 M [EMIM][OTf] as a supporting electrolyte, as shown in Figure 8.7. It is known that in the radical-radical coupling, further oxidation of oligomers and polymer deposition in the electrooxidative polymerization are favorably affected because the reaction products are accumulated in the vicinity of the electrode surface under slow diffusion conditions, and consequently the polymerization rate is increased. It is reasonable to assume that the polymerization rate in [EMIM][OTf] is higher than that in the conventional media, since neat [EMIM][OTf] (viscosity ... 

JT Eleveld, HA Claessens, JL Ammerdorfer, AM van Herk, CA Cramers. Evaluation of mixed-mode stationary phases in liquid chromatography for the separation of charged and unchaiged oligomer-like model compounds. J Chromatogr A 677 211-227, 1994. 

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