Ionization from ring position

While the ortho ionization data are generally fitted with notably poorer precision than for the m- and p- positions, there appear to be characteristic trends indicative of predominant contributions from polar and resonance effects. Thus, for ionization from the ring position (pyridinium ions), p yX" > whereas for ionization from the side-chain position (anilinium ions and phenols),... 

In these terms, Shatenshtein s partial rate factors (37) for the H—D exchange of monosubstituted benzenes in liquid ammonia are not anomalous (2m). The analysis of this rate data is included in Table XXVIII. Even though the data are not precise enough to meet the desired standard of precision of fits, the sequences > X and P/> p p - P/ are clearly evident in the results. Consequently, this data set (which is of the or type) may be taken as providing supporting evidence with the pyridinium ionization (which is of the gr type) for unique X blends for the positions o- and p- to ionization from the ring position as compared with the X blends for side-chain ionization. 

Figure 29.4, illustrates a schematic diagram of a flame-ionization detector. It comprises of a positively charged ring (also referred to as cylindrical collector electrode), whereas the flame jet serves as the negative electrode. The flame jet has two inlets from the bottom of the column effluent is introduced and from the side H2 to form the fuel, whereas air is let in uniformly around the base of the jet. 

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