Single-stage liquid-phase synthesis of methyl isobutyl ketone under mild conditions

Abstract

In this study, a catalyst mixture of activated Mg/Al hydrotalcite as solid base and Pd on carbon nanofibers was investigated for the single-stage liquid-phase synthesis of methyl isobutyl ketone (MIBK) from acetone and H 2 at 313 K and H 2 pressures of 1-20 bar. With this catalyst system acetone and H 2 are selectively converted into MIBK in a single reactor, even at 1.2 bar H 2 . Although the hydrogenation of one of the intermediates, mesityl oxide (MO), at 1.2 bar suffers from severe mass transfer limitations in H 2 , the catalytic activity in the single-stage synthesis is stable over several hours if the steady-state concentration of MO is kept low. Under the presented conditions the dehydration reaction of diacetone alcohol to MO is rate limiting in the production of MIBK.

A hydrotalcite-based catalyst system for the single-stage liquid-phase synthesis of MIBK

“…After heat treatment of HT as the surface area as well as the pore volume increased significantly. Only with HT heat micropores were observed, caused by the evolution of water and CO 2 during heat treatment of HT as [25,32,36,37]. After rehydration of the mixed oxide (HT re ) a BET surface area similar to that of HT as was found, whereas Pd/HT re exhibited a relatively low surface area.…”

“…HT with an Mg/Al ratio of 2 was prepared via coprecipitation [25,31]. To an aqueous solution (70 ml) containing 0.…”

“…Pd was deposited on carbon nanofibers (0.9 wt% Pd) by ion adsorption as described elsewhere [25,34]. Carbon nanofibers (CNF) were grown out of synthesis gas (CO/H 2 ) using a commercial 57 wt% Ni/SiO 2 catalyst (Engelhard Ni5270P) at a growth temperature of 773 K. Removal of the growth catalyst and oxidation of CNF was performed by treatment in KOH and subsequently in concentrated HNO 3 , followed by thorough washing.…”

“…Hydrogenation experiments and the singlestage synthesis of MIBK were performed in a semi-batch slurry reactor operating at a constant pressure of 1.2 bar H 2 at 313 K [25,35]. The set-up consisted of a thermostated stirred doublewalled glass reactor, equipped with baffles and a gas-tight mechanical stirrer.…”

“…Recently, we reported a preliminary study of a hydrotalcitebased catalyst system consisting of a physical mixture of activated Mg-Al hydrotalcites (HT) and palladium supported on carbon nanofibers (Pd/CNF) for the single-stage synthesis of MIBK [25]. This catalyst system converts acetone and H 2 into MIBK in the liquid-phase under mild conditions (331 K and 1.2 bar H 2 ) with high selectivity, although more research is required to further improve the activity.…”