Pyridine-2,6-dicarboxylic add

Fig. 3-156. Simultaneous analysis of nine different heavy metals. — Separator column IonPac CS5 eluent 0.004 mol/L pyridine-2,6-dicarboxylic add + 0.002 mol/L Na2S04 + 0.015 mol/L NaCl, pH 4.8 with LiOH flow rate, detection, and injection volume see Fig. 3-152 solute concentrations 10 ppm Pb2+, 1 ppm Fe3+, Cu2+, Ni2+, Zn2+, and Co2+, 3 ppm Cd2+, 1 ppm Mn2+ and Fe2+.

Figure 10.170 Determination of iron(lII), copper, and zinc In a chromic add plating bath. Separator column lonPac CS5A eluent 6mmol/L pyridine-2,6-dicarboxylic acid+ 8.6 mmol/L LiOH flow rate 1 mU/min detection ...

The kinetics of the oxidations of the mixed-metal cuboidal complexes [MojNiS4(H20)io] -" and [Mo3FeS4(H20)io] + by [Co(dipic)2] (dipic =pyridine-2,6-dicarboxylate) and [Fe(H20)6] have been studied as a function of acid concentration/ The oxidations by the cobalt complex are acid-independent and outer-sphere, whereas the oxidations by Fe " (aq) proceed by outer-sphere acid-independent ([Fe(H20)j] " ) and inner-sphere (OH -bridged) add-dependent ([Fe(H20)50H] ) pathways. 

The most common reaction of this type is the cyclization of various derivatives of hydrazine and substituted hydrazines with pyridine o-dicarboxylic adds and related compounds. Reactions in which the acid derivative reacts directly with the hydrazine are dealt with as [4 + 2] reactions in Section 2.15.10.6.1. 

More recendy, aramids have been obtained by direct polycondensation of aromatic dicarboxylic adds and aromatic diamines in amide solvents using triphenyl phosphite and pyridine as condensing agents. This method uses dicarboxylic acids which are easier to handle than acid chlorides and eliminates the additional step of converting the dicarboxylic adds into add chlorides. Lithium chloride and calcium chloride have also been added to these polymerization mixtures to increase polymer solubility. This method has been used to synthesize both flexible and rodlike polyamides with high inherent viscosity values (ie, up to 6.2 dL/g). It has also been shown that additional triphenyl phosphite ensures complete polymerization with... 

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