Synthesis Of MIBK Research Articles

Higher Acetone Conversion Obtained Over a TiO2–Pd Bifunctional Catalyst for Liquid-Phase Synthesis of Methyl Isobutyl Ketone: The Role of Al2O3 Support

We reported a bifunctional catalyst TiO2/Al2O3 and Pd/Cor for one-pot liquid-phase synthesis of MIBK from acetone in this paper. The characterizations of FT-IR, Raman spectra, TEM, XPS, CO2-TPD, NH3-TPD, Py-IR and TGA spectra revealed that the TiO2/Al2O3 could possess more acid sites and especially Lewis acid sites due to the coexistence of TiO2 and Al2O3. So a higher acetone conversion 35–45% at 150 °C and 2.0 MPa pressure was achieved than ever reported for MIBK liquid-phase synthesis. In addition, the catalyst could keep active for at least 90 h on stream at 80–90% MIBK selectivity. The phenomenon of carbonaceous accumulation on TiO2/Al2O leaded to the deactivation of catalyst. Because of the coexistence of TiO2 and Al2O3. TiO2/Al2O3 could have more acid sites and especially Lewis acid sites. For liquid-phase synthesis of methyl isobutyl ketone, bifunctional catalyst TiO2/Al2O3&Pd/Cor showed higher acetone conversion.

An efficient bifunctional catalyst of TiO2 coating and supported Pd on cordierite for one-pot synthesis of MIBK from acetone

We report here an efficient bifunctional catalyst of TiO2 coating and supported Pd on cordierite (T500/Cor&Pd/Cor) for one-pot synthesis of MIBK from acetone. The obtained 75% MIBK selectivity at 60% acetone conversion was the best performance ever reported for metal oxide based catalyst, without obvious deactivation for at least 12h on stream. The superior performance of T500/Cor&Pd/Cor could be attributed to the dominant base sites and moderate acid sites on TiO2 coating caused by the nanoscale anatase crystallite, and its combination style of being physically mixed with Pd.

HZSM-5 supported silica–zirconia and its application in one-step synthesis of methyl isobutyl ketone

Abstract In order to adjust the acidity and texture property of HZSM-5, SiO2–ZrO2 was introduced via a modified sol–gel method. Pd-loaded catalyst was prepared and its catalytic activity was tested in one-step synthesis of MIBK. The catalyst exhibited a significant activity of acetone conversion up to 33.4% and MIBK selectivity up to 88.1% under atmospheric pressure. The acidity and textural properties of support material, as well as palladium dispersion of Pd-loaded catalyst were characterized. The results indicated that the proper acid strength and textural property of the support, together with the high dispersion of palladium resulted in good catalytic performance.

Direct synthesis of MIBK from acetone over Pd/NaX catalysts

The one-step synthesis of MIBK from acetone in gas phase was studied over palladium catalysts on NaX zeolite (1 and 3 wt% of Pd). A greater selectivity to MIBK was observed for a H 2/acetone ratio of 6.2. Although increasing the reaction temperature caused an increase of the selectivity to condensation products, the temperature for which the selectivity to MIBK was maximum was the lower one (523 K). Decreasing the reduction temperature from 633 to 573 K for PdNaX enhanced the hydrogenation activity and decreased MIBK selectivity. Selectivities to MIBK as high as 80% were obtained.

Effect of acidic and metallic sites on the catalytic performance of Pd/ZSM-5 catalysts in the one-step synthesis of mibk

The acidic properties of Pd/ZSM-5 catalysts were characterized by NH3-TPD and FT-IR of d3-acetonitrile adsorption. Effect of Pd loading on the catalytic activity and product distribution was studied in the one-step synthesis of methyl isobutyl ketone from acetone. The results indicated that a proper balance between acidic and metallic sites was necessary to obtain high catalytic performance.

Influence of the acid sites density in the acetone transformation over bifunctional Pt/H[Ga]ZSM5 catalysts

The purpose of this work is to elucidate the effect of acid sites density on the catalytic behaviour of a series of bifunctional catalysts prepared by supporting platinum (about 1.00 wt.%) on MFI-type gallosilicates (H[Ga]/ZSM5 with Si/Ga atomic ratio = 16, 46 and 145). The XPS characterization studies of the bifunctional catalysts allowed to detect the presence of framework as well as extraframework gallium species for the catalyst with highest density of acid sites (Si/Ga = 16), while only framework Ga species could be detected for catalysts with lower acid site density. It was also verified in all the bifunctional catalysts the presence of three types of metal sites: Pt (0), Pt–O ads and PtO species. The results obtained in the synthesis of MIBK from acetone with the different bifunctional solids, indicate that as the density of the acid sites increases, the solids start to behave solely as acid catalysts. This phenomenon is probably related to the presence of extraframework gallium species in the catalyst with higher surface acidity, capable to interact with the platinum species and thus provoking the passivation of the metallic phase, while in the solids with lower surface acidity it seems to exist a better balance between the acidic–metallic functionalities.

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

A comparative study was performed between Pd supported on activated hydrotalcites bi-functional catalysts and physical mixtures of activated hydrotalcites with Pd supported on carbon nanofibers for the single-stage liquid-phase synthesis of methyl isobutyl ketone from acetone and H 2. Since it was found earlier that the dehydration reaction of diacetone alcohol over activated hydrotalcites is the rate-determining step in this process, Mg–Al hydrotalcites were investigated in the condensation of acetone to diacetone alcohol and its dehydration to mesityl oxide to enhance the activity. A correlation between the number of active base sites, as determined by volumetric CO 2 adsorption measurements at low pressures, and the activity in the dehydration reaction could be derived. A dependency on the Pd-loading (0–1 wt%) of Pd supported on activated hydrotalcites catalysts was found in the single-stage synthesis of methyl isobutyl ketone, whereas no such an effect was found when using physical mixtures of activated hydrotalcites with Pd on carbon nanofibers. Results from TEM, CO 2 chemisorption and N 2 physisorption as well as catalytic experiments in the hydrogenation of mesityl oxide and of cyclohexene indicate that this dependency is largely accounted for by entrapment of Pd particles in the agglomerates of the irregular stacks of hydrotalcite platelets, making these sites inaccessible for the reactants.

Hydrotalcites supported on carbon nanofibers as solid base catalysts for the synthesis of MIBK

Mechanically strong carbon nanofiber spheres of millimeter size were grown from methane over a preshaped Ni/SiO 2 catalyst. Mg–Al hydrotalcites (HTs) were precipitated in the porous carbon bodies by consecutive impregnation of the reactants and an aging step. In a single sequence, HT loadings as high as 16 wt% were obtained. HTs turned out to be present as platelets with a lateral size of ∼20 nm supported on the carbon nanofibers. After activation by heat treatment and subsequent rehydration, a high number of accessible Brønsted base sites were found (0.7–0.9 mmol g −1 HT), as determined by CO 2 adsorption measurements. High specific activity of the supported HTs was found in the self-condensation of acetone, more than four times higher than that of unsupported catalysts. The greatly improved efficiency of the supported HTs was ascribed to the high number of active edge sites. Results show no loss of HTs from the carbon bodies after catalysis and demonstrate that the used catalyst can be easily reactivated by the thermal activation procedure. An efficient and mechanically strong catalyst for the single-stage liquid-phase synthesis of methyl isobutyl ketone from acetone and H 2 at 331 K was obtained with the deposition of Pd and HTs on the same support.

Characterization and reactivity of Pt/Al<Subscript>2</Subscript>O<Subscript>3</Subscript>/SS thin films

Highly crystalline and pure MCM-22 was prepared by dynamic method hydrothermally. The relevant physicochemical properties were characterized by N 2 adsorption, XRD, TEM and FTIR methods. One-step synthesis of MIBK was investigated over Pd/MCM-22. These catalysts showed a conversion of 34p and a selectivity of 86.9p.

Synthesis, characterization of MCM-22 and catalytic activity in one-step synthesis of methyl isobutyl ketone

Highly crystalline and pure MCM-22 was prepared by dynamic method hydrothermally. The relevant physicochemical properties were characterized by N2 adsorption, XRD, TEM and FTIR methods. One-step synthesis of MIBK was investigated over Pd/MCM-22. These catalysts showed a conversion of 34% and a selectivity of 86.9%.

Preparation, characterization of MCM-56 and catalytic activity in one-step synthesis of MIBK from acetone

High crystalline MCM-56 was synthesized by dynamic method hydrothermally, and it was used as supports to prepare Pd/MCM-56 catalysts by ion-exchange method. The materials were characterized by means of N 2 adsorption, XRD, TEM, TPD. We found that as-made MCM-56 was made of very thin MWW-type layers with only one unit cell along the c direction. One-step synthesis of methyl isobutyl ketone from acetone was investigated over Pd/MCM-56. A conversion of 33.5% and a selectivity of 81.2% to MIBK were achieved. A stable MIBK yield was also obtained as well, maintaining 72 h of time on stream.

Bifunctional Metal/Base Catalysts (Pt/X) for the Direct Synthesis of MIBK from Acetone

The synthesis of MIBK was studied over Pt supported on NaX and CsX zeolites. The activity increased as both the temperature and the H2/Ac ratio were increased. Temperature had also a beneficial effect on the selectivity to MIBK but the H2/Ac ratio had an opposite effect. Activities and selectivities were always higher for Pt/NaX than for Pt/CsX. For Pt/NaX, increasing the reduction temperature increased the activity but decreased the selectivity to MIBK. Both catalysts were quite stable and selectivities to MIBK of 70% were obtained over PtNaX at 613 K and H2/Ac=0.5. The absence of both strong acidic and strong basic sites and a proper balance between metallic and basic sites are responsible for the behavior observed.

Synthesis of MIBK from Acetone in a Single Step over Ni/AIPON Catalysts

Synthesis of MIBK from Acetone in a Single Step over Ni/AIPON Catalysts

One step synthesis of mibk (methyl isobutyl ketone) from acetone over CaO-supported Ni catalyst

One step synthesis of MIBK from acetone over Ni/CaO catalysts was studied. 10 wt% Ni/CaO catalysts were prepared by conventional impregnation method (catalyst I), and liquid phase oxidation method using NaOCl as an oxidant (catalyst L). Catalyst L showed much higher activity than catalyst I because of recovered CaO pore structure and high BET surface area. Catalyst C, prepared by coprecipitation method, showed 60% of MIBK selectivity with a fairly high overall acetone conversion. Catalysts L and C had two CO2 desorption states (α, Β). Incorporated Ni enabled support precursor [Ca(CO)3] to decompose easily into CaO andCO2even at low temperature and generated weakCO2desorption state (α) which was from active state.