Heterogeneous Catalysts for the One-Pot Synthesis of Chemicals and Fine Chemicals

One-pot cascade reactions which involve multifunctional catalysts possessing different functions on the surface attract a growing interest. Relevant examples of the use of this type of catalysts in one-pot syntheses involving hydrogenation/dehydrogenation and aldol condensation reactions which give rise to valuable organic compounds are reported in this paper. It is shown that the layered double hydroxides (LDH) are precursors materials particularly adapted for the preparation of catalysts exhibiting acido/basic and redox sites. The paramount importance of the nature (Lewis or Bronsted) and the strength of the basic sites, as well as the nature of the metallic function of the supported metal catalysts obtained from LDH is discussed. It is emphasized on the equilibrium between the basic and metallic functions required to reach high activities and selectivities.

Layered double hydroxides: precursors for multifunctional catalysts

One-step syntheses of methyl isobutyl ketone are studied over palladium supported on aluminophosphate molecular sieves: SAPO-11 and AlPO4-11. The effects of reaction condition, metal loading, acidic and basic properties, pore size and methods of metal loading are investigated. The results show that a balance between the condensation and hydrogenation is necessary for high selectivity of MIBK. Basic sites promote the activity. The selectivities of MIBK are improved by loading Pd by ion-exchange, occlusion in the pores or acid treatment of the support. Close contacts of the mutifunctional sites are necessary for higher selectivity.

One step synthesis of methyl isobutyl ketone over palladium supported on AlPO4-11 and SAPO-11

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

The transformation of acetone was carried out over a 04 wt% PtHMFI catalyst (SiAl = 60) under the following conditions: flow reactor, 160°C, pressures of acetone and hydrogen equal to 075 and 025 bar, respectively Methylisobutylketone, propane and traces of mesityloxide are observed as primary products while the other main products: 2-methylpentane and diisobutylketone result from secondary transformation of methylisobutylketone The reactivity of the reaction products and of probable intermediates: diacetone alcohol, isopropanol and propene was compared to that of acetone, which allows us to establish the complete scheme of acetone transformation Acetone is competitively transformed through bifunctional catalysis into methylisobutylketone and into propane The limiting step of methylisobutylketone formation is acetone aldolisation over the acid sites of the catalyst while that of propane formation is acetone hydrogenation over platinum sites Methylisobutylketone undergoes the same competitive bifunctional transformations leading to diisobutylketone (limiting step: acid coaldolisation of acetone and of methylisobutylketone) and to 2-methylpentane (limiting step: hydrogenation of methylisobutylketone)

Transformation of acetone over a 0.4PtHMFI(60) catalyst. Reaction scheme

Summary Acidic ion exhange resins are used for manufacturing both bulk chemicals and fine chemicals. The present paper relates to different routes of producing methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIK) and methyl isopropenyl ketone (MIPK) using a palladium-doped ion exchange resin as a catalyst. A new process variant for alternatively manufacturing MIPK and MIK with the same equipment is delineated.

Saturated and Unsaturated Ketones Manufactured by Heterogeneous Catalysis

Strongly acid cation exchange resins (I) are based on crosslinked styrene copolymers with opt. substd. benzenesulphonyl (BS) gps. contg. exchange-active sulphonic acid gps. Also claimed is a process for the prodn. of (I) by reacting crosslinked styrene copolymers (II) with benzenesulphonyl chloride (III) in presence of AlCl3 and then sulphonating the prod. by a known method.

Michael Dr Dettmer

Papers

Saturated and Unsaturated Ketones Manufactured by Heterogeneous Catalysis

Crosslinked styrene] copolymers with sulphonated benzene-sulphonyl gps.