Quinoline could be carbonized at 300-450°C using of ZrCl4 as the carbonization promoter. The carbonization reaction path of quinoline, changes of Zr left in carbonized products by high temperature treatments up to 2500°C and the oxidation of carbonized and graphitized products (powder) in air have been studied.
The formation of a complex between quinoline and ZrCl4 and the analyses of Tetrahydrofuran-solubles in carbonized products led to the conclusion that the carbonization reaction of quinoline is a kind of additional polycondensation of the quinoline molecules, in which complexes formed between ZrCl4 and quinoline act as reaction intermediates and the hydrogen atoms unbound move to other parts of molecules to produce hydroaromatic rings, followed by partial rupturing and isomerization of the hydroaromatic rings formed.
ZrCl4, added as a carbonization promoter, was left mainly as loose ZrO2 crystals in carbonized products, which developed into rigid crystals by treatments up to 1500°C and changed to ZrC crystals at higher temperature treatments of 2000-2500°C: ZrO2/C composites were formed at up to 1500°C and ZrC/C composites at 2000-2500°C.
The carbonized products from quinoline were graphitized by as the heat treatment temperatures rised.
The reactivity in air of ZrC/C composites formed at higher than 2000°C was almost the same as that of a mixture of ZrC and C, and that of the parent carbon material decreased with the growth of the graphite structure by an increase in the heat treatment temperatures. Similarly, the parent carbon in ZrO2/C composites showed a graduall decrease in reactivity for oxidation with an increase in the heat treatment temperatures, though more reactive than ZrC/C composites.
