The activity and the selectivity of cobalt catalysts supported on a crystallised and on an amorphous zirconia were compared with cobalt supported on a γ-alumina catalyst. The catalysts supported on zirconium dioxide were found to present a better reducibility of the active phase and also to be capable of hydrogen adsorption via a spillover mechanism. It is proposed that these properties could account for a better catalytic activity and an increase

The performances in ethane oxidation of VOx/zirconia and VOx/titania (anatase) catalysts prepared by various procedures (see part I) are compared with a reference to H4PMo11VO40 (HPA) supported on the same supports. Acetic acid is produced in small amounts (yield HPA/zirconia > VOx/titania. In the case of VOx/zirconia, no acetic acid is produced; this is ascribed to the more basic character of zirconia, which strongly holds adsorbed acetic acid (HPA

A high surface area amorphous zirconia and a medium surface area tetragonal zirconia were used as supports for vanadium oxide catalysts and compared with titania (anatase). The vanadia phase is deposited according to various methods: impregnation of the supports by colloidal vanadia solutions (an original procedure), conventional impregnation by ammonium metavanadate, grafting of vanadylacetylacetonate. The characterization is performed at the different

Recently, there has been a marked increase in the interest shown in catalysis by gold. It is now recognised that gold has unique properties as a catalyst for many reactions with pre-eminence in the oxidation of carbon monoxide. However, it is also known that supported gold catalysts can be used for other reactions involving carbon monoxide, for example the water gas shift reaction. Supported gold catalysts have also been shown to be effective for

Mg:Al hydrotalcites (Mg:Al ratios 3:1, 3:2 and 4:1) have been characterised using the decomposition of 2-methylbut-3-yn-2-ol as a probe reaction for the acidic/basic properties. The hydrotalcites were used either as synthesised, or following calcination at 225 and 450 °C. All gave almost exclusively of base-catalysed products (98-99%) and a very small amount of acid-catalysed products (1-2%). For this probe reaction only slight differences in reactivity

The oxidation of cyclohexane to cyclohexanol and cyclohexanone are investigated using supported gold catalysts using mild conditions of temperature and pressure. These catalysts are found to show some limited activity at 70 °C. However, the gold catalysts do not exhibit significantly different behaviour from supported Pt or Pd catalysts, and the selectivity observed is solely a function of conversion which in turn is a function of reaction time.

One reason for the few commercial successes of intensified catalytic multiphase reactors might be that many of these developments inherently incorporate a fixed catalyst, which may not suit an industry that is based on principles of batch manufacture and multiproduct plants. This study evaluates an intensified reactor that encompasses the opportunities demonstrated from structured flows and thin channels, together with a mobile, slurry catalyst,

The applicability of a monolith system to a retrofit application for the hydrogenation of pyrolysis gasoline (Pygas) is evaluated. A direct comparison between a trickle bed (extruded trilobe) and a washcoated monolith is made using a simulated model Pygas mixture. Comparable nickel impregnated onto alumina catalysts (trilobe and monolith) are evaluated in a laboratory recycle reactor operating under the same industrially relevant conditions of temperature,

Supported Au catalysts are investigated for the oxidation of primary alcohols under solvent-free conditions in the absence of base. Three representative primary alcohols have been investigated: benzyl alcohol, octan-1-ol and geraniol using a range of supports for gold nanocrystals prepared using coprecipitation, deposition precipitation and impregnation. For benzyl alcohol and octan-1-ol selective oxidation to the corresponding aldehydes is observed,