• Journal of the Korean Chemical Society
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• v.46 no.1
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• pp.57-63
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• 2002

The hydropurification reaction of CTA (crude terephthalic acid) was carried out with hydrogen over PdRu/CCM (carbon-carbonaceous composite material) catalyst in a batch reactor at high temperature. The first order kinetics of hydropurification is confirmed with the linear dependence of ln(4-CBA; 4-carboxybenzaldehyde) with reaction time. The reaction condition studied is thought to represent the hydropurification well because of the linear dependence of catalytic activity on the catalyst weight. The p-toluic acid (p-tol) in solid and liquid increases with the conversion of reaction or the decrease of 4-CBA. However, the benzoic acid (BA) concentration does not depend much on the conversion. The AT (alkali transmittance) does not depend on the 4-CBA when the concentration is higher than about 0.2% which shows the 4-CBA, in itself, does not cause the coloring effect. The AT of PTA depends inversely with the concentration of 4-CBA when the 4-CBA is less than about 0.15%. This may show the coloring materials are removed in parallel with the hydrogenation of 4-CBA. The (0.3%Pd-0.2%Ru)/CCM shows larger residual catalytic activity than a commercial catalyst, 0.5%Pd/C, after using in a commercial reactor even though the former has smaller fresh activity than the latter. The palladium and ruthenium in PdRu/CCM show the synergetic effect in activity when the ruthenium concentration is about $0.2{\sim}0.35$ wt%. It may be supposed that the PdRu/CCM catalyst can be a promising candidate to replace the commercial Pd/C catalyst.