Hydrogenation of renewable vegetable oils and their alkyl-esters catalyzed by transition metals complexes

Doctoral Dissertation uoadl:1309483 592 Read counter

Unit:
Τομέας ΙΙΙ [Ανόργανη Χημεία – Ανόργανη Χημική Τεχνολογία – Περιβαλλοντική Χημεία]
Library of the School of Science
Deposit date:
2014-05-19
Year:
2014
Author:
Μπουριάζος Αχιλλέας
Dissertation committee:
Γεώργιος Παπαδογιαννάκης Αναπληρωτής Καθηγητής (Επιβλέπων),Νικόλαος Χατζηχρηστίδης Ομότιμος Καθηγητής, Κωνσταντίνος Μερτής Ομότιμος Καθηγητής
Original Title:
Υδρογόνωση των Ανανεώσιμων Φυτικών Ελαίων όπως και των Αλκυλεστέρων τους καταλυόμενη από Σύμπλοκα των Στοιχείων Μετάπτωσης
Languages:
Greek
Translated title:
Hydrogenation of renewable vegetable oils and their alkyl-esters catalyzed by transition metals complexes
Summary:
In this thesis we study the selective hydrogenation of polyunsaturated methyl
esters of renewable vegetable oils to the corresponding monounsaturated
counterparts and the hydrogenolysis of their ester groups to yield fatty
alcohols catalyzed by transition and main-group metal complexes in
aqueous/organic two-phase or organic monophasic systems.
The selective hydrogenation of polyunsaturated methyl esters of soybean oil
catalyzed by water-soluble rhodium and palladium complexes modified with
trisulfonated triphenylphosphine (TPPTS) takes place with high catalytic
activities in aqueous/organic two-phase systems. Water-soluble
nitrogen-containing ligand modifiers such as disulfonated bathophenanthroline
(BPhDS) or ethylenediaminetetraacetic acid (EDTA) could finely tune the
coordination sphere of palladium to obtain highly active and stable catalytic
systems and with Pd/BPhDS catalysts in the same biphasic hydrogenation reaction
a turnover frequency (TOF) up to 113200 h-1 has been achieved which is much
higher than that exhibited by Pd/TPPTS catalytic systems. The biphasic
hydrogenation of methyl esters of Cynara cardunculus alternative non-edible oil
catalyzed by Ru/TPPTS upgrades the quality of obtained biofuel which is second
generation biodiesel because this oil does not compete with edible vegetable
oils. Large scale production experiments of Cynara cardunculus have confirmed
the high potential of this recently recognized energy crop as an industrial
feedstock with many applications.
The biphasic hydrogenation of polyunsaturated vegetable oils and their methyl
esters catalyzed by water-soluble complexes of main-group metals such as
calcium, modified with nitrogen-containing ligands such as EDTA, is highly
interesting because calcium is non-toxic and very economic and Ca/EDTA
catalysts exhibited high catalytic activities (TOF = 63200 h-1) combined with
high stabilities due to their recyclabilities and furthermore because this
reaction demonstrated again a new application in the field of aqueous-phase
catalysis.
The hydrogenolysis of methyl esters of palm kernel oil to the corresponding
fatty alcohols catalyzed by a huge number of water-soluble catalytic complexes
in aqueous/organic two-phase systems proved to be a very difficult reaction
where with catalytic complexes of ruthenium modified with tetrasulfonated
tetraphenylporphyrine the conversion was up to 17% and the selectivity towards
fatty alcohols almost quantitative namely 99%.
Keywords:
Hydrogenation, Hydrogenolysis, Methyl esters of vegetable oils, Fatty alcohols, Complexes of transition and main-group metals
Index:
No
Number of index pages:
0
Contains images:
No
Number of references:
216
Number of pages:
217
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