STABILITY OF CRACKED NAPHTHAS FROM THERMAL AND CATALYTIC PROCESSES AND THEIR ADDITIVE RESPONSE .1. EVALUATION OF STABILITY AND ADDITIVE RESPONSE

Olefinic naphthas derived from fluid catalytic cracking (FCC) or therm al cracking units are increasingly being used in high-octane motor gas oline with growing concern for resulting fuel quality. Hindered phenol s and substituted arylamines are the two classes of antioxidants gener ally used for improving the stability of gasoline. The olefin types in cracked naphthas depend strongly on the process from which they are d erived and hence are expected to show different responses with differe nt antioxidants. However, systematic information on this aspect of ant ioxidant action is non-existent in the literature. Using two represent ative commercial antioxidants from each class with representative naph thas (FCC, visbreaking and coker), it was found that phenolic antioxid ants gave a better response with thermally cracked naphthas. With amin e-type antioxidants no clear preference could be observed.