In total 18 large-scale preparations were made. Alumna, copper-alumina, LaCo and La-Ni pillars were studied. Raw and acid-activated clays were examined (including montmorillonite and saponite). Impregnated materials (with V205 and organics) were also studied. The process engineering aspects associated with moving from small (~ 5g) to large (~ Kg) were identified. Important parameters include keeping constant the mixing and aging conditions for intercalant preparation and the same for all productions. Control of the calcination step was also found to be important if damage to the PILC structure is to be avoided.
The concept of acid-activating a clay prior to pillaring was studied - variation of acid activation was made for saponite and montmorillonite clays. Al, Zr, Cr and Ti were amongst the pillars incorporated. The products were characterized sing PXRD, surface area, chemical analysis, TGA, cylcohexylamine and pyridine adsorption as well as testing in several Bronsted reactions.
Mixed Al-pillared clays were prepared with La, Si, Cr, Cu. Various pillaring conditions were tested eg dilute solutions, concentrated slurries and dry powder addition. A comparison of lab-scale and Kg scale production of Cu-Al (using a Greek and Tunisian Bentonite) was made. Preliminary oxidation studies were performed as well as in the hydroconversion of heptane. In this reaction it was found that Al-pillared saponites were viable alternatives to commercial zeolites.
New physical methods have been investigated. For pillaring, a vacuum-assisted filtration technique was used and shown to be a promising means of speeding the pillaring process. Pillaring using concentrated solutions was also investigated. Electrical measurements were shown to be advantageous in following the steps associated with pillaring as well as allowing microwave pillared materials to be more fully characterised and compared with conventional PILCs.
Finally a range of applications were assessed. These included in the catalysis area: hydroisomerisation, hydrocarbon cracking, alcohol oxidation and dehydration, synthesis of MTBE and bis-phenol-A, alkylation, oxidation of phenols, NO+CO conversion. Opportunities in the area of agrochemicals were also explored. Laboratory and field tests demonstrated that organo-modified PILCs shown maintained herbicidal activity with decreased loss to underground waters.
Overall, key steps in the preparation of PILCs were explored and the potential for using PILCs in commercial areas identified.
The project will probe the underlying chemistry associated with the synthesis of pillared days (PILCs) in kilogramme quantities and it will develop the necessary facilities for the production of PILCs in pilot-scale quantities. The intention is to produce (at the kg level) pillared material with controlled and well characterized properties. Four types of starting clays-both synthetic and natural-will be chosen and a variety of pillars explored. The necessary characterization and testing facilities which will be required will be optimised during the course of the work. Full characterisation and performance data in processes monitoring catalytic as well as adsorption properties will be investigated. The materials will be tested for a variety of model processes so that potential commercial users of the pillared materials will have performance data available to assist them in assessing potential applications in new and established areas of materials chemistry and science.
Funding SchemeCSC - Cost-sharing contracts