Zeolite adducts

Tri-iron dodecacarbonyl zeolites adducts. The adducts Fe3(C0)12-HY and Fe3(CO) 2-NaY were used as starting materials. 

Dicobalt octacarbony1-NaY zeolite adducts.Only the adducts Co2(C0)g-NaY were used as starting materials. No decomposition trough thermal treatment was attempted before the catalytic runs. 

Storage in inorganic solid matrix Intercalation into graphite [6,7] Carbon-bromine adduct [4] In zeolites [8]... 

Pietrzyk, P., Piskorz, W., Sojka, Z. et al. (2003) Molecular structure, spin density distribution, and hyperfine coupling constants of the i7l CuNO n adduct in the ZSM-5 zeolite DFT calculations and comparison with EPR data, J. Phys. Chem. B., 107, 6105. 

Sojka, Z., Che, M. and Giamello, E. (1997) EPR investigation of the electronic structure of mononuclear copper(I) nitric oxide adduct formed upon low-pressure adsorption of NO onto Cu/ZSM-5 zeolite, J. Phys. Chem. B, 101, 4831. 

Water adsorption on high silica zeolites. Formation of hydroxonium ions and hydrogen-bonded adducts... 

The Fe3(C0)- 2"Y adducts are prepared under argon atmosphere with the HY and NaY zeolites previously heated under vacuum at 350°C. The impregnation of the support is performed either from pentane solution at 25°C or from dry mixing of the carbonyl and the zeolite to avoid any complication from the solvent. In this last preparation the sample stands in vacuo for 2kh at 60°C in order to favour the sublimation of the carbonyl into the pores of the zeolite. 

Bi s(cyclopentadi enyldi c arbonyliron)-zeolit es adduct s. The adducts CpFe(CO)2 2 HYand CpFe(CO)2 2 NaY were used as starting materials. They are not decomposed before the catalytic run. Infrared spectra of these materials show that the integrity of the molecular complex is retained it is expected that owing to its size, which is smaller than that of Fe3(C0)- 2,... 

The CpFe(C0)2 2 hy adduct exhibits no catalytic activity in the temperature range studied (200-300°C). However cyclo-pentene and cyclopentane are detected through GC monitoring of the gas-phase. A redox reaction Fe(0)/H+ is still occurring as for the Fe3(C0)12"HY adduct the evolved hydrogen allows the reduction of the cyclopentadienyl ligands. This behaviour already provides evidence for the location of the Fe(l) complexes within the large cavities of the zeolite. 

An increased selectivity for phenol in the oxidation of benzene by H202 with TS-1 catalyst in sulfolane solvent was attributed to the formation of a bulky sulfolane-phenol adduct which cannot enter the pores of TS-1. Further oxidation of phenol to give quinones, tar, etc. is thus avoided. Removal of Ti ions from the surface regions of TS-1 crystals by treatment with NH4HF2 and H202 was also found to improve the activity and selectivity (227). The beneficial effects of removal of surface Al ions on the catalytic performance of zeolite catalysts for acid-catalyzed reactions have been known for a long time. 

Anilines are converted into nitrosoarenes ArNO by the action of hydrogen peroxide in the presence of [Mo(0)(02)2(H20) (HMPA)]224, whereas catalysis of the reaction by titanium silicate and zeolites results in the formation of azoxybenzenes ArN (0)=NAr225. Azo compounds ArN=NAr are formed in 42-99% yields by the phase-transfer assisted potassium permanganate oxidation of primary aromatic amines in aqueous benzene containing a little tetrabutylammonium bromide226. The reaction of arylamines with chromyl chloride gives solid adducts which, on hydrolysis, yield mixtures of azo compounds, p-benzoquinone and p-benzoquinone anils 234227. 

Y.Z. Zhang, T.T. Wong, and W.M.H. Sachtler, The effect of Ca + andMg + ions on the formation of electron-deficient palladium-proton adducts in zeolite, J. Catal. 128, 13-22 (1991). 

X. L. Bai and W. M. H. Sachtler, Methylcyclopentane conversion catalysis by zeolite encaged palladium clusters and palladium-proton adducts, J. Catal. 129, 121-129 (1991). 

Lewis acid sites have empty orbitals able to accept electron density from the occupied orbitals of a Lewis base, in parallel with back-donation from the catalyst to the empty anti-bonding orbitals of the base [33]. This interaction leads to the formation of an activated acid-base adduct. In the case of alkanes activation may proceed by hydride abstraction [38]. Y and Beta are good examples of zeolites with Lewis acidity, often quite significant for catalysis [39, 40]. 

These intrazeolite singlet oxygen ene reactions have synthetic potential because the cis effect observed in solution is suppressed in the zeolite [13]. Consequently, allylic hydroperoxides which are inaccessible by other routes may be available via this new technology. For example, photo-oxidations of aryl-substituted alkenes, 7, in sensitizer-doped NaY react to generate the allylic hydroperoxides as the major or exclusive product [17]. In contrast, in solution, the hydroperoxides are formed in only 5-20% yields, with 2-1-2 and 4-1-2 adducts dominating the reaction mixtures. In the case of 2-methyl-5-phenyl-2-hexene, 8, the regio-selectivity for 8b and 8c improved from 47% to 94% and the diastereoselectivity from 10% to 44% as the reaction is moved from solution into the zeolite [18] ... 

The spectral behavior of CO bonded to metal atoms (metal carbonyls) has been used to characterize the surface of solids (61). For instance, it is known that metal carbonyl interacts with surface site of metal oxides and zeolites to form a Lewis-type adduct where a CO ligand of the metal carbonyl interacts (via the oxygen atom) with surface OH groups or with co-ordinatively unsaturated metal ions (surface Lewis acid sites) (62,63). On the other hand, thermal treatment of the metal carbonyl support adducts lead to loss of CO with formation of subcarbonyls, which are anchored to the support (64,65). Papile et al. (66) reported the characterization... 

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