Leonardo Dalloro

Shape selective conversion of 1,2,4-trimethylbenzene over different zeolite frameworks

Abstract The upgrading of Pseudocumene (1,2,4-TMB) to more valuable methylbenzenes over acidic zeolites with variable acidic and diffusive properties is studied, using reactivity tests and IR spectroscopy. The concurrent reactions investigated include isomerization and transalkylation. At low conversion levels the isomer distribution in C 8 , C 9 and C 10 products is not thermodynamically controlled, being different over different zeolite frameworks, indicating shape selectivity. Variable temperature experiments allow to identify the location of active sites for the different reactions on different catalysts, and the nature of shape selectivity.

Novel nanocomposite material

A spherical nanocomposite S-1/SiO 2 has been prepared, starting from a milk slurry of silicalite-1 (S-1) crystallites and a fluid siliceous gel, precursor of an amorphous silica, with a narrow pore size distribution in the mesopore region (MSA). The spherical particles show a core of nanocrystalline S-1 and an outer shell of nanoporous MSA, so the novel composite material is formed by two different nanostructured units, each preserving their individuality. The performances of nanocomposite material in the Beckmann rearrangement of cyclohexanone oxime are comparable with those of S-1, while the MSA binder behaves as an inert.

15-O-05 - The beckmann rearrangement catalyzed by silicalite: a spectroscopic and computational study

Publisher Summary This chapter discusses the rearrangement of cyclohexanone oxime to caprolactam over zeolites with MFI and FAU structure by means of spectroscopical (IR) and computational methods. Hydrogen bond interactions, proton transfer, and rearrangement are detected. The thermal reaction mechanism and that catalyzed by H + are studied with the quantum-mechanics (QM) methods of B3LYP/6-31+G (d,p) quality. The same reaction path in presence of HCl and silanol is described to model the acids of different strength. The H + -catalyzed mechanism is found to be a multistep mechanism in which proton transfer from N to O in the oxime is the rate-determining step.