01083nas a2200193 4500008004100000022001400041245016200055210006900217260011000286300001200396490000600408520025500414100002600669700001300695700001800708700001400726700001900740856013000759 2005 eng d a1463-926200aGreen process for chlorine-free benzaldehyde from the solvent-free oxidation of benzyl alcohol with molecular oxygen over a supported nano-size gold catalyst0 aGreen process for chlorinefree benzaldehyde from the solventfree aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a768-7700 v73 a

Benzyl alcohol is oxidized selectively to benzaldehyde with high yield, with a little formation of benzylbenzoate, by molecular oxygen over a reusable nano-size gold catalyst supported on U3O8, MgO, Al2O3 or ZrO2 in the absence of any solvent.

1 aChoudhary, Vasant, R.1 aDhar, A.1 aJana, Prabhas1 aJha, Rani1 aUphade, B., S. uhttps://library.ncl.res.in/content/green-process-chlorine-free-benzaldehyde-solvent-free-oxidation-benzyl-alcohol-molecular-002638nas a2200205 4500008004100000022001400041245017900055210006900234260007300303300001000376490000800386520175900394653002602153653003002179653002802209653002502237100002602262700001402288856013002302 2007 eng d a0926-860X00aGaClx- or GaAlClx-grafted Si-MCM-41: highly active and moisture insensitive/stable catalyst for the acylation and benzylation of benzene, naphthalene and substituted benzenes0 aGaClx or GaAlClxgrafted SiMCM41 highly active and moisture insen aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC a42-480 v3333 a

GaClx- and GaAlClx-grafted Si-MCM-41 catalysts were prepared by reacting anhydrous GaCl3 and mixed anhydrous GaCl3 and AlCl3, respectively, with the terminal hydroxyl groups of Si-MCM-41 (pore size: 2.5 nm) in a dry non-aqueous reaction medium (CCl4) under reflux. The catalysts showed high activity for both the acylation and benzylation (with benzoyl chloride and benzyl chloride, respectively) of benzene, toluene, p-xylene, cumene, mesitylene, anisole and naphthalene. Both the catalysts are moisture insensitive or less moisture sensitive; the presence of moisture has a beneficial effect in the acylation over both the catalysts. The catalytically active sites of the GaClx-grafted Si-MCM-41 are (-O-)(2)GaCl (i.e. partially chlorided Ga anchored to Si through -O- linkage) species and the equivalent sites of the GaAlClx-grafted Si-MCM-41 are (-O-)(2)Ga(or Al)Cl and (-O-)(3)Ga(or Al) species. The high acylation/benzylation activities of both the catalysts even in the presence of moisture are attributed to their redox properties (Ga3+ -> Ga1+) rather than to their Lewis acid properties. After the grafting/chemical bonding, the grafted gallium chloride catalyst showed much higher acylation activity but lower benzylation activity than the physically deposited (on Si-MCM-41) or unsupported GaCl3. The GaAlClx-grafted Si-MCM-41 showed higher acylation activity than the GaClx-grafted Si-MCM-41, due to a synergetic effect of the Ga and Al species. However, the relative benzylation activity of the two catalysts showed strong dependence upon the presence or absence of electron donating group(s) and also upon the electron donating ability of the group(s) attached to the aromatic nucleus. (c) 2007 Elsevier B.V. All rights reserved.

10aacylation benzylation10aGaAlClx-grafted Si-MCM-4110aGaClx-grafted Si-MCM-4110amoisture insensitive1 aChoudhary, Vasant, R.1 aJha, Rani uhttps://library.ncl.res.in/content/gaclx-or-gaalclx-grafted-si-mcm-41-highly-active-and-moisture-insensitivestable-catalyst-001616nas a2200193 4500008004100000022001400041245014200055210006900197260007300266300001400339490000600353520080100359653003001160653002901190653003201219100002601251700001401277856013101291 2008 eng d a1566-736700aGaAlCl(x)-grafted Mont.K-10 clay: highly active and stable solid catalyst for the friedel-crafts type benzylation and acylation reactions0 aGaAlClxgrafted MontK10 clay highly active and stable solid catal aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a1101-11050 v93 a

A liquid phase reaction of anhydrous GaCl(3) and AlCl(3) with the surface hydroxyl groups (with HCl evolution) of Mont. K-10 clay in dry CCL(4) under reflux resulted in a novel GaAlCl(x),-grafted Mont.K-10 catalyst [with Cl/(Ga + Al) = 1]. The catalyst showed high activity and stability in the Freidel-Crafts type benzylation and benzoylation (by benzyl chloride and benzoyl chloride, respectively) of benzene, naphthalene and substituted benzenes, even in the presence of moisture. It also showed good activity for the benzoylation of nitrobenzene (i.e. even in the presence of strong electron withdrawing group, like nitro group, attached to the benzene ring). The catalytically active surface species in the catalyst are -(O)(2)-Ga(or Al)Cl. (c) 2007 Elsevier B.V. All rights reserved.

10abenzoylation of aromatics10abenzylation of aromatics10aGaAlCl(x)-grafted Mont.K-101 aChoudhary, Vasant, R.1 aJha, Rani uhttps://library.ncl.res.in/content/gaalclx-grafted-montk-10-clay-highly-active-and-stable-solid-catalyst-friedel-crafts-type-0