Scientific career of Fabrizio Cavani in brief Scientific Interests

14. F. Cavani, S. Luciani, E. Degli Esposti, C. Cortelli, R. Leanza “Surface Dynamics of A Vanadyl
Pyrophosphate Catalyst for n-Butane Oxidation to Maleic Anhydride: An In Situ Raman and
Reactivity Study of the Effect of the P/V Atomic Ratio”, Chemistry Eur. J., 16 (2010) 1646-1655.
15. F. Cavani, D. De Santi, S. Luciani, A. Lofberg, E. Bordes-Richard, C. Cortelli, R. Leanza,
“Transient reactivity of vanadyl pyrophosphate, the catalyst for n-butane oxidation to maleic
anhydride, in response to in-situ treatments”, Appl. Catal. A 376 (2010) 66–75.
During the period 2008-2011, FC has extensively studied the mechanism of a process which,
although industrially applied since several years, yet had not been understood. Specifically, the
reaction is the gas-phase methylation of phenol with methanol, catalyzed by basic (doped
MgO: General Electric technology) or redox (V/Fe/O: Asahi technology) oxides, a reaction
occurring with high region- and chemo-selectivity. It was generally accepted that the mechanism of
the reaction is a direct electrophylic substitution by methanol on the activated phenolate molecule.
Starting from the evidence that such mechanism is not convincing, we were able to demonstrate
that indeed the reaction mechanism involves formaldehyde as true electrophylic molecule, where
the aldehyde is formed by means of dehydrogenation of methanol, a reaction which is accelerated
by the basic materials used industrially [1-6]. The electrophylic attack leads to the formation of
salycilic alcohol as the reaction intermediate, which is finally transformed into the methylated
compound (o-cresol and then 2,6-xylenol) by means of MPV-type reaction with formaldehyde itself,
which also acts as a reducing agent for the methylol moiety. In overall, the reaction indeed consists
of several steps, which are carried out in rapid cascade. In this sense, the direct transformation of
phenol into the corresponding methylated compounds is emblematic of how the combination of
various catalyst functionalities (both basic, required for the phenol activation, and dehydrogenating)
allows the conduction of complex reactions with high selectivity (one-pot reactions).
1. N. Ballarini, F. Cavani, L. Maselli, A. Montaletti, S. Passeri, D. Scagliarini, C. Flego, C. Perego,
“The transformations involving methanol in the acid- and base-catalyzed gas-phase methylation of
phenol”, J. Catal. 251 (2007) 423–436
2. N. Ballarini, F. Cavani, L. Maselli, S. Passeri, S. Rovinetti, “Mechanistic studies of the role of
formaldehyde in the gas-phase methylation of phenol”, J. Catal. 256 (2008) 215-225
3. N. Ballarini, F. Cavani, S. Passeri, L. Pesaresi, A.F. Lee, K. Wilson, “Phenol methylation over
nanoparticulate CoFe2O4 inverse spinel catalysts: The effect of morphology on catalytic
performance”, Appl. Catal. A 366 (2009) 184–192
4. F. Cavani, L. Maselli, S. Passeri, J.A. Lercher, “Catalytic methylation of phenol on MgO –
Surface chemistry and mechanism”, J. Catal. 269 (2010) 340–350
5. V. Crocellà, G. Cerrato, G. Magnacca, C. Morterra, F. Cavani, S. Cocchi, S. Passeri, D.
Scagliarini, C. Flego, C. Perego, “The balance of acid, basic and redox sites in Mg/Me-mixed
oxides: The effect on catalytic performance in the gas-phase alkylation of m-cresol with methanol”,
J. Catal. 270 (2010) 125–135.
6. V. Crocellà, G. Cerrato, G. Magnacca, C. Morterra, F. Cavani, L. Maselli and S. Passeri, “Gasphase
phenol methylation over Mg/Me/O (Me = Al, Cr, Fe) catalysts: mechanistic implications due
to different acid–base and dehydrogenating properties”, Dalton Trans., 39, (2010) 8527–8537.