Alberto de Angelis

Alkylation of benzene catalysed by supported heteropolyacids

A new kind of solid acid based on heteropolyacids has been proved to be a useful catalyst in alkylation of benzene with propylene to obtain cumene. The new catalysts are based on a heteropolyacid supported on zirconia treated with very low contents of sulphate anions. Two different heteropolyacids have been studied, both with Keggin structure, (H 3 PMo 12 O 40 , H 3 PW 12 O 40 ), and both produced active catalysts. The zirconia was used either pure or doped with few percent of iron oxide. The catalysts have been characterised through XRD, 31 P NMR and HREM. These catalysts are very active in alkylation reaction even at mild temperature. Their two outstanding features are the low n-propylbenzene production and the possibility to regenerate it at moderate temperature (350°C). The best catalyst is based on H 3 PW 12 O 40 supported on zirconia doped with iron and treated with sulphate ions.

Heteropolyacids as effective catalysts to obtain zero sulfur diesel

This paper deals with the catalytic properties of different supported heteropolyacids (HPAs), both molybdenum- and tungsten-based, in the oxidative desulfurization process of diesel. We are jointly developing a new oxidative desulfurization process, aimed at reducing the sulfur content in diesel to less than 10 ppm (parts per million) using in situ produced peroxides. In this new process, high-molecular-weight organosulfur compounds, such as 4,6-dimethyl-dibenzothiophene (DMDBT), difficult to be eliminated by conventional hydrodesulfurization, are oxidized to the corresponding sulfones and subsequently removed by adsorption. Molybdenum-based HPAs, with Keggin structure, proved to be the most active and selective catalysts for oxidizing DMDBT with on-stream lifetimes exceeding 1500 h time on stream (t.o.s.).

Alkylation of Methyl Linoleate with Propene in Ionic Liquids in the Presence of Metal Salts

Vegetable oils and fatty acid esters are suitable precursor molecules for the production of a variety of bio-based products and materials, such as paints and coatings, plastics, soaps, lubricants, cosmetics, pharmaceuticals, printing inks, surfactants, and biofuels. Here, we report the possibility of using Lewis acidic ionic liquids (ILs) to obtain polyunsaturated ester dimerization-oligomerization and/or, in the presence of another terminal alkene (propene), co-polymerization. In particular, we have tested the Lewis acidic mixtures arising from the addition of a proper amount of GaCl3 (Χ > 0.5) to two chloride-based (1-butyl-3-methylimidazolium chloride, [bmim]Cl, and 1-butylisoquinolium chloride, [BuIsoq]Cl) or by dissolution of a smaller amount of Al(Tf2N)3 (Χ = 0.1) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][Tf2N]. On the basis of product distribution studies, [bmim][Tf2N]/Al(Tf2N)3 appears the most suitable medium in which methyl linoleate alkylation with propene can compete with methyl linoleate or propene oligomerization.

New Method for H2S Removal in Acid Solutions

Several different technologies are available for H(2)S removal from the gas stream of medium capacity. Among them, the most widely used is Locat with more than 120 plants worldwide. In the last decade, many new processes, such as Sulfatreat-DO, Crystasulf, Caltech, and UCSR, were proposed to overcome the drawbacks of the state-of-the-art processes (low sulfur purity, chemical degradation, thiosulfate formation). We have developed a new H(2)S conversion method based on acid ferric nitrate solution, co-catalyzed by a heteropolyacid. H(2)S was converted to pure sulfur (>99.9 %), with no traces of organic compounds. Due to the acid pH of the solution, no chelant or surfactant was needed and iron content in the solution could reach very high levels. Keggin heteropolyacid (H(6)PW(9)V(3)O(40)) catalyzed the reoxidation of reduced ferrous solution with air at mild temperature and at very high reaction rate. The undesired side reaction (NO(x) formation) could be avoided by simply increasing the oxygen partial pressure.

Exploring and exploiting different catalytic systems for the direct conversion of cellulose into levulinic acid

The conversion of cellulose into target chemicals is essential for the development of the sustainable chemical industry of the future. To this end, the single step transformation of cellulose into levulinic acid (LA) has been investigated in different aqueous systems and using either Bronsted acidic ILs, metal salts, or a mixture of these as catalysts with or without the formation of carbonic acid in situ. The effect of varying the reaction parameters, such as temperature, time, substrate concentration, and catalyst loading, on conversion and selectivity has been studied. A few different systems [(TMGH)(HSO4)–FeCl3 or (TMGH)(HSO4)–CrCl3 in H2O–CO2, (TMGH)(HSO4)–CrCl3 in H2O, FeCl3 in H2O, and FeCl3 or CrCl3 in H2O–CO2] allowed for the isolation of LA in good yields (41–55 mol%). The best and remarkably high yield of LA (69 mol%) has been obtained in water at 195 °C (4 h) by using TiOSO4 (0.375 wt%) as a catalyst. This new, environmentally friendly catalytic system retains high activity after five consecutive runs. Its catalytic activity has been discussed taking into account the hydrolysis process occurring under the reaction conditions.

Catalytic Processes for Environmentally Friendly Methylene Diphenyl Diisocyanate Production

Isocyanates are industrially produced using strong mineral acids (e.g. HCl), in the condensation of aniline to produce methylenedianiline (MDA), and phosgene, in the conversion of MDA to the corresponding isocyanates. Huge quantities of sodium chloride, contaminated with organic compounds, are produced during process, and their disposal is a relevant issue.