ISSN:
1572-879X
Keywords:
heteropoly acid
;
palladium modification
;
propene oligomerisation
;
coke formation
;
catalyst regeneration
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The coking during propene oligomerisation and subsequent regeneration of both silica-supported heteropoly acid H3PW12O40 (PW) and its palladium-modified form (1.6–2.5 wt% Pd) have been studied. 31P MAS NMR studies have revealed that the Keggin structure of the catalyst was unaffected by coke deposition in both unmodified PW/SiO2 and Pd-modified form. As shown by 13C MAS NMR and TGA/TPO, the Pd modification affects the nature of the coke formed: for the standard catalyst (PW/SiO2) both soft coke, comprising mainly high molecular weight aliphatic oligomers, and hard coke, comprising polynuclear aromatics, are formed whilst on the Pd-modified catalyst only the soft coke is observed. Coke formation causes strong deactivation of the catalyst in the oligomerisation of propene. The aerobic burning of coke on the unmodified PW/SiO2 occurs in the temperature range of 470–520°C. Doping the catalyst with Pd significantly decreases this temperature to allow catalyst regeneration at temperatures as low as 350°C without loss of catalytic activity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1019083103395
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