The role of temperature program and catalytic system on the quality of acrylonitrile-butadiene-styrene degradation oil

Thermal and catalytic degradation of acrylonitrile-butadien-styrene copolymer (ABS) was performed at 450°C by semi-batch operation. Four different temperature programs were used for thermal degradation. SA4 silica alumina and three SA4/iron oxide combinations (γ-Fe 2 O 3 , a Fe 3 O 4 -C composite and α-FeOOH) were used for catalytic degradation. The heating rate affects the quality of the degradation oil, the following heating program giving the lowest amount of heavy nitrogen-containing compounds: room temperature→400°C (heating rate β =10°C min −1 )→450°C ( β =1°C min −1 ; then isothermally hold at 450°C for 210 min). SA4 catalyst used in liquid phase contact mode has a cracking effect on ABS degradation. The SA4/iron oxide catalytic systems give better results than the separate use of the catalysts, converting the heavy nitrogen (N)-containing compounds into light aliphatic nitriles that can be easily removed from the degradation oil by distillation. With SA4/α-FeOOH system the amount of 4-phenylbutyronitrile, the main N-containing compound from ABS thermal degradation, was strongly decreased in oil, from 17.5 to 1.7 wt.%.