One-step methyl isobutyl ketone (MIBK) synthesis from 2-propanol: Catalyst and reaction condition optimization

doi:10.1016/j.apcata.2006.10.010

Applied Catalysis A: General

Volume 317, Issue 2, 7 February 2007, Pages 161-170

https://doi.org/10.1016/j.apcata.2006.10.010 Get rights and content

Abstract

A gas-phase process for methyl isobutyl ketone (MIBK) synthesis from 2-propanol in one-pot is studied as an alternative to the conventional technology for producing MIBK from acetone (DMK). Bifunctional copper/acid–base catalysts able to operate at mild temperatures and atmospheric pressure were prepared and characterized by measuring the acid and base properties as well as the metal dispersion. It was found that a Cu-Mg-Al mixed oxide catalyst gives high MIBK yields. In this catalyst, the metal fraction in loadings of 2–6 wt% promotes the hydro-dehydrogenation steps at high rates whereas the surface acid–base sites of moderate acid and base properties favor the aldol condensation reaction.

The effect of different operational conditions such as reaction temperature and reactant partial pressure was also investigated. The MIBK formation rate was enhanced by increasing 2-propanol partial pressure in a wide range, consistently with a positive 2-propanol reaction order in the overall kinetics whereas the presence of hydrogen in the reactant mixture inhibited MIBK synthesis due to a negative order with respect to H₂. An increase of the reaction temperature and the use of inert atmosphere improved the MIBK yield. By operation at 533 K in N₂ the Cu-Mg-Al catalyst with 6.4 wt% Cu, yields 27% MIBK in comparison to the 30% typically obtained in current commercial liquid-phase high-pressure processes from DMK.

Graphical abstract

The one-pot gas-phase synthesis of methyl isobutyl ketone (MIBK) from 2-propanol is studied using bifunctional catalysts under mild conditions. The effect of the catalyst copper content and acid–base properties as well as that of the operational conditions on the MIBK yield is investigated. Copper loadings of 2–6 wt% and moderate catalyst Lewis acidity and Brönsted basicity are required to obtain MIBK yields of 27%, values comparable with the current commercial process from acetone (DMK) at high pressures.

Introduction

4-Methyl-2-pentanone, methyl isobutyl ketone (MIBK), acetone (DMK) and methyl ethyl ketone are the aliphatic ketones most produced worldwide. In particular, MIBK is widely used as a solvent for vinyl, epoxy and acrylic resin production as well as for dyes and nitrocellulose. MIBK is also employed as an extracting agent for antibiotic production or removal of paraffins from mineral oils, in the synthesis of rubber chemicals, and in fine chemistry applications [1], [2]. The global demand for MIBK is estimated in 300,000 t per year.

Nowadays, MIBK is industrially obtained in a one-step liquid-phase process from DMK and H₂ at low temperatures (393–433 K) and high pressures (1–10 MPa) in multitubular fixed bed reactors. The chemical reaction for this process is depicted in Eq. (1).

Several reaction steps are comprised in Eq. (1): (i) aldol condensation of DMK to diacetone alcohol; (ii) dehydration of diacetone alcohol to mesityl oxide (MO); (iii) hydrogenation of the C double bond C bond of MO to MIBK. Therefore, multifunctional catalysts such as Pd or Pt supported on sulfonated resins, which contain condensation, dehydration and hydrogenation functions are used in the industrial process [1], [3]. Both the aldol condensation and the dehydration reactions are reversible at 393–433 K [3] but the catalyst shifts the equilibrium in favor of MO by irreversibly hydrogenating it to MIBK [4].

In the commercial process, DMK conversion is typically 30–40% and the selectivity to MIBK reaches 90%. Thus, MIBK concentration in the reactor effluent before distillation is usually lower than 30 wt%. In addition to the MIBK purification cost, the process requires high pressures to operate efficiently.

There is therefore a great interest for developing novel one-step processes able to operate at atmospheric pressure with comparable or better MIBK yields. Recently, Talwalkar and Mahajani [5] summarized conversion and selectivity of the most promising catalysts reported in the literature for MIBK synthesis from DMK at atmospheric or high pressures. Group VIII or IB metals such as Pd, Pt, Ni and Cu on acidic or basic supports like aluminosilicates, zeolites, mixed oxides and ion exchange resins are mostly postulated. In particular, Pd [4], [6], [7], [8] or Ni [9], [10] supported on Mg–Al or Zr–Cr mixed oxides, alumina, HZSM5, Cu/MgO [11] and Cu–Mg alloy powders [12] are reported to provide, in gas-phase and atmospheric pressure, MIBK yields similar or higher than that of the industrial process. However, none of these catalysts have been commercially implemented and there are no industrial plants operating in the gas-phase at atmospheric pressure.

The DMK used as reactant in the current commercial process must be obtained from other sources in a separate reactor. The main DMK manufacturing processes are: (i) Wacker–Hoechst direct oxidation of propane; (ii) dehydrogenation of 2-propanol; (iii) co-product of the phenol synthesis by the Hock process. The most important route worldwide is the Hock process followed in Western Europe, USA and Latin America by the dehydrogenation of 2-propanol [13]. In the latter process, DMK is synthesized from 2-propanol in fixed bed reactors at 493–573 K on Cu-based catalysts [1]. In MIBK manufacturing plants using this technology, the unreacted 2-propanol is then recycled, and hydrogen and DMK are stripped from the product mixture and sent to the MIBK synthesis unit. However, DMK must be previously purified and cooled down, thus increasing the operating cost of the MIBK synthesis.

Several attempts have been reported on the direct ketone synthesis from alcohols. In 1936, Dupont patented a one-step ketone synthesis process from secondary alcohols, in which MIBK was obtained with a 21 wt% yield on a copper-based catalyst at 600–633 K and 100–700 kPa [14]. Other pioneering works can be found in references [15], [16]. In a previous work [17], we postulated a gas-phase process for the synthesis of MIBK in one-step at mild temperatures and atmospheric pressure using 2-propanol as reactant. This process is intended to be used in solvent manufacturing plants where producing a mixture of DMK, MIBK and other higher oxygenates would present high commercial interest. The overall reaction for this synthesis process is represented in Eq. (2):

Main consecutive reactions involved in the reaction network from 2-propanol are: (i) dehydrogenation of 2-propanol; (ii) self-condensation of DMK to the α,β-unsaturated intermediate, MO; (iii) hydrogenation of the C double bond C bond of MO to MIBK.

This direct process from 2-propanol presents several technical advantages, such as to overcome the unfavorable thermodynamics of the MIBK synthesis from DMK, that must be carried out at low temperatures and high pressures and forms concomitantly significant amounts of 2-propanol. Furthermore, 2-propanol is commonly used in fine chemistry as a source of hydrogen for the gas-phase reduction of unsaturated ketones or aldehydes [18], [19], [20]. This hydrogen donor capacity of 2-propanol allows to carry out the MIBK synthesis from 2-propanol without supplying gas-phase hydrogen.

In this paper, we continue our investigations on the MIBK synthesis from 2-propanol using bifunctional catalysts that combine in intimate contact a metallic function needed for the hydro-dehydrogenation steps with an acid–base site required by the aldol condensation reaction. We have prepared and characterized several Cu-based catalysts with different copper loadings and acid–base properties and we have compared their catalytic performance. In addition, we investigated the effect of the operational variables such as reaction temperature on the catalyst activity and stability and MIBK yield. We also studied the effect of varying the 2-propanol and hydrogen partial pressures on the overall kinetics.

Our goal was to determine the optimum catalyst metal loading and acid–base properties required for the MIBK synthesis as well as the most favorable reaction conditions for improving the MIBK yield. Results show that a low-copper loading Cu-Mg-Al catalyst operating in the gas-phase at atmospheric pressure, relatively high temperatures and inert atmosphere gives MIBK yields similar to that of the industrial process from DMK at high pressures. Furthermore, the MIBK yield can be improved further by increasing the 2-propanol partial pressure in the feed.

Section snippets

Catalyst preparation

Catalyst precursors of Cu-containing CuM_I(M_II)O_x mixed oxides, where M_I and M_II are metal cations like Mg²⁺, Al³⁺ or Ce³⁺, were prepared by coprecipitation following similar procedures. An aqueous solution of the metal nitrates with a total [Cu²⁺ + M_I + M_II] cation concentration of 1.5 M was contacted with an aqueous solution of KOH and K₂CO₃ at a constant pH of 10. Both solutions were simultaneously added dropwise to 300 mL of distilled water kept at 338 K in a stirred batch reactor. The resulting

Reaction network and preliminary catalyst selection for MIBK synthesis

The synthesis of MIBK from 2-propanol, Eq. (2), involves the reaction sequence depicted in Scheme 1. In the first reaction step, 2-propanol is dehydrogenated to DMK (step 2a). A catalytic formulation for MIBK synthesis must then include an active and selective metal for promoting 2-propanol dehydrogenation. In our case, we selected copper because of its known catalytic properties for the selective conversion of alcohols to carbonyl compounds such as aldehydes and ketones [22], [23], and also

Conclusions

The one-step synthesis of MIBK from 2-propanol is satisfactory carried out at mild temperatures and atmospheric pressure on a Cu_zMg₁₀Al₇O_x bifunctional catalyst that combines in intimate contact the metallic function (Cu⁰) required for hydro-dehydrogenation steps and the acid–base pair sites needed for the C double bond C bond forming aldol condensation reaction leading from DMK to MIBK. The copper loading can be varied between 2 and 6 wt% without affecting the catalyst activity, selectivity and stability.

Acknowledgements

Authors thank the Universidad Nacional del Litoral (UNL), Santa Fe and the Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), Argentina for the financial support of this work (grant PICTO 13234 BID 1728/OC-AR). The authors also thank H. Cabral for technical assistance.

References (43)

A. Mitschker et al.
Y.Z. Chen et al.
Appl. Catal. A: Gen.
(1998)
S. Talwalkar et al.
Appl. Catal. A: Gen.
(2006)
E.F. Kozhevnikova et al.
J. Catal.
(2006)
M.J. Martinez-Ortiz et al.
J. Mol. Catal. A: Chem.
(2003)
R. Unnikrishnan et al.
J. Mol. Catal. A: Chem.
(1999)
V. Chikan et al.
J. Catal.
(1999)
A. Molnar et al.
Mater. Sci. Eng. A
(2001)
J.I. Di Cosimo et al.
J. Catal.
(2002)
T.M. Jyothi et al.
J. Mol. Catal. A: Chem.
(2001)

M.A. Aramendía et al.

Appl. Catal. A: Gen.

(1998)

A. Dandekar et al.

J. Catal.

(1998)

J.I. Di Cosimo et al.

Appl. Catal. A: Gen.

(1996)

M. Xu et al.

J. Catal.

(1997)

V.K. Díez et al.

J. Catal.

(2006)

J.I. Di Cosimo et al.

J. Catal.

(1998)

C. Morterra et al.

J. Catal.

(1978)

V.K. Díez et al.

J. Catal.

(2003)

S.-M. Yang et al.

Appl. Catal. A: Gen.

(2000)

R. Barth et al.

Catal. Commun.

(2002)

J.C. Kenvin et al.

J. Catal.

(1991)

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One-step methyl isobutyl ketone (MIBK) synthesis from 2-propanol: Catalyst and reaction condition optimization

Abstract

Graphical abstract

Introduction

Section snippets

Catalyst preparation

Reaction network and preliminary catalyst selection for MIBK synthesis

Conclusions

Acknowledgements

Appl. Catal. A: Gen.

Appl. Catal. A: Gen.

J. Catal.

J. Mol. Catal. A: Chem.

J. Mol. Catal. A: Chem.

J. Catal.

Mater. Sci. Eng. A

J. Catal.

J. Mol. Catal. A: Chem.

Appl. Catal. A: Gen.

J. Catal.

Appl. Catal. A: Gen.

J. Catal.

J. Catal.

J. Catal.

J. Catal.

J. Catal.

Appl. Catal. A: Gen.

Catal. Commun.

J. Catal.