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By using isopropanol as alkylating agent in the direct alkylation of benzene to cumene, under properly selected conditions, performances comparable to those afforded by the current industrial use of propylene have been obtained. The reaction is carried out in the presence of a β-zeolite-based catalyst. Catalytic performances are influenced by temperature and pressure at fixed benzene to isopropanol molar ratio. In particular, catalyst activity and catalyst deactivation rate depend on the water content in the liquid phase fraction of the reaction mixture, as predicted by state equations for LV equilibria in the reacting system. The successful use of isopropanol as alkylating agent has paved the road toward a viable acetone recycle in phenol production, as foreseeable in case of acetone/phenol unbalanced demand.

Manufacturing methods of dimethylcarbonate (DMC) are examined, in particular those which have been industrially exploited. Apart from the old phosgenation process, two processes based on the oxy-carbonylation of methanol went on stream: the copper chloride catalysed, one step liquid-phase process, by EniChem, and the palladium catalysed, two steps gas-phase process, via methylnitrite, by UBE. Two further technologies are attractive for full-scale development in the next future: the gas-phase direct methanol oxy-carbonylation and the alkylenecarbonate transesterification process. In the last few years, the use of DMC in the chemical industry has considerably grown, due to its chemical properties and its non-toxicity, an outstanding example being represented by the non-phosgene production of aromatic polycarbonates. Other very promising fields of large scale DMC application are as solvent and as oxygenate in reformulated fuels.

Dans le domaine de la chimie environnementale, plus particulierement celle des procedes et de l'utilisation de produits plus surs, la substitution de reactifs tels que le phosgene est un objectif important. Le dimethyl carbonate (DMC), compose non toxique, compatible avec l'environnement, represente actuellement un substitut possible au phosgene. S'appuyant sur des proprietes catalytiques du CuCl, Enichem a developpe, a l'echelle industrielle, le premier procede de production sans phosgene du DMC, production basee sur la reaction, en une etape d'oxy-carbonylation, du CH 3 OH. Dans le procede commercial de preparation de polycarbonates aromatiques, l'utilisation du DMC et du diphenylcarbonate (DPC) comme intermediaires evite, non seulement l'usage du phosgene, mais egalement celui du chlorure de methylene comme solvant, et previent la formation de NaCl comme co-produit. Une methode de preparation d'isocyanates sans phosgene, via la thermolyse du carbamate obtenu par la reaction d'une amine avec le carbonate correspondant, est actuellement en cours de developpement.

Ti4+ ions structurally contained in titanium silicalite (TS-1) and ETS-10 samples, two nanoporous materials, have been studied by means of voltammetric measurements. Both structurally tetrahedral and octahedral Ti4+ ions show electrochemical response. In particular, by using acid solutions, it was possible to distinguish, in TS-1, between signals coming from different titanium species. Finally, it has been proven that the use of acid solutions allows us to discriminate between Ti4+ ions in TS-1 and in ETS-10 since only the former is able to coordinate water molecules, the reduction of which can be monitored by the presence of a peak at −600 mV/SSE. Keywords: Zeolites, Titanosilicates, Cyclic voltammetry

The interaction of NH 3 with Ti-silicalite-1 (TS-1) was studied by means of adsorption microcalorimetry IR, XANES and EXAFS techniques. A specific interaction with Ti(IV) sites was revealed and quantitatively and energetically described, in comparison with silicalite taken as a reference material. The adsorption was found to be largely reversible but a minor amount of ammonia was irreversibly held at the surface of TS-1. The energetic spectrum obtained by the heat of adsorption versus coverage plot is quite wide in both TS-1 (40 q ads −1 ) and silicalite (40 q ads −1 ), indicating not only that different processes occur at the surface but that a few highly energetic sites are present on TS-1. The standard pre-treatment of the samples in ammonium acetate aqueous solution lowers the whole adsorption capacity of TS-1 surface (as well of silicalite at about the same degree), but not the number of NH 3 molecules adsorbed per Ti atom, which is close to two for both untreated and treated TS-1 samples. The most energetic sites are preferentially suppressed by the ammonium acetate treatment on both TS-1 and silicalite, as shown by the heat of adsorption values much lower for the treated samples than for the untreated ones. Parallel IR and XANES–EXAFS results were found to support these findings.

Oxidative carbonylation of methanol to dimethylcarbonate catalysed by cobalt complexes is reported. Cobalt complexes with oxygen and or nitrogen donor ligands such as carboxylate, acetylacetonate, picolinate and Schiff bases are suitable catalysts. The oxidative carbonylation of methanol catalysed by cobalt complexes which has never been reported, affords dimethylcarbonate with remarkably high selectivities. Of the cobalt complexes, those with Schiff bases show the highest reactivity. The influence of co-solvents was also examined.