Jm. Nagpal et al., STABILITY OF CRACKED NAPHTHAS FROM THERMAL AND CATALYTIC PROCESSES AND THEIR ADDITIVE RESPONSE .2. COMPOSITION AND EFFECT OF OLEFINIC STRUCTURES, Fuel, 74(5), 1995, pp. 720-724
Olefinic concentrates were separated from two naphthas, one from fluid
catalytic cracking (FCC) and one thermal crackate, using column chrom
atography. The composition and structure of the olefins were determine
d by a combination of analytical techniques. FCC naphthas contain rela
tively higher levels of conjugated dienes. The monoolefins are highly
branched. The thermal crackates have higher levels of a-olefins and ab
ound in mono-, di-, tri- and conjugated cyclic olefins. Stability test
s on these olefinic concentrates blended in low-S,N straight-run napht
ha showed that cyclic olefins are very active gum formers. Representat
ive commercial antioxidants (hindered phenols and phenylenediamines) b
oth gave good responses to different olefin concentrate test blends. H
indered phenols had a marginally better effect.