Palladium-doped

Density-functional study of palladium-doped small gold clusters. Physical Review B - Condensed Matter, 67, 115420-1-115420-4. 

Scheme 4.4 Sonogashira coupling on palladium-doped alumina.

The group of Ley has reported on the use of palladium-doped perovskites as recyclable and reusable catalysts for Suzuki couplings [151]. Microwave-mediated cross-couplings of phenylboronic acid with aryl halides were achieved within 1 h by utilizing the supported catalyst (0.25 mol% palladium) in aqueous 2-propanol (Scheme 7.127). The addition of water was crucial as attempted transformations in non-aqueous mixtures did not proceed. 

Scheme 7.127 Suzuki couplings utilizing palladium-doped perovskite as catalyst.

A rapid MW-assisted palladium-catalyzed coupling of heteroaryl and aryl boronic acids with iodo- and bromo-substituted benzoic acids, anchored on TentaGel has been achieved [174]. An environmentally friendly Suzuki cross-coupling reaction has been developed that uses polyethylene glycol (PEG) as the reaction medium and palladium chloride as a catalyst [175]. A solventless Suzuki coupling has also been reported on palladium-doped alumina in the presence of potassium fluoride as a base [176], This approach has been extended to Sonogashira coupling reaction wherein terminal alkynes couple readily with aryl or alkenyl iodides on palladium-doped alumina in the presence of triphenylphosphine and cuprous iodide (Scheme 6.52) [177]. 

Acidic ion exchange resins are used for manufacturing both Dulk chemicals and fine chemicals. The present paper relates to different routes of producing methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIK) and methyl iso-propenyl ketone (MIPK) using a palladium-doped ion exchange resin as a catalyst. A new process variant for alternatively manufacturing MIPK and MIK with trie same equipment is delineated. 

Lately, a number of papers have dealt with microwave-assisted reactions on palladium-doped A1203. Villemin reported on Stifle, Suzuki, Heck and Trost—Tsuji reactions where potassium fluoride on alumina was used as the base26. The reactions were carried out without solvent or stabilising phosphine ligands in single-mode reactors. The Stifle reactions were noteworthy as the toxic organotin residue remained adsorbed on the solid support, thus allowing a simplified work-up procedure for the otherwise unpleasant, and toxic, stannous by-products. Both the Stifle and the Suzuki reactions could be performed under air. Furthermore, it was noted that with experiments where the... 

Wang, J.X., Yang, Y.H., Wei, B.G., Hu, Y.L. andFu, Y., Microwave-assisted cross-coupling reaction of sodium tetraphenylborate with aroyl chlorides on palladium-doped KF/AI2O3, Bull. Chem. Soc. Jpn., 2002,75,1381—... 

Kabalka, G.W., Wang, L., Pagni, R.M., Hair, C.M. and Namboodiri, V., Solventless Suzuki coupling reactions on palladium-doped potassium fluoride alumina, Synthesis, 2003, 217-222. 

Keywords iodobenzene, alkylboronic acid, Suzuki coupling, palladium-doped... 

Oxygen Desorption and Conductivity Change of Palladium-Doped Tin(IV) Oxide Gas Sensor... 

V.P. Glazkov, V.P. Zhukov, V.A. Somenkov, and T.N. Ivanova, Interaction of palladium doped fullerene with hydrogen, Ibid., 71, (1999). 

Metal(0) deposited at the Ti02 surface may enhance yields and selectivity of the reduction products [28-30], In the presence of copper(0)-loaded Ti02 formaldehyde and methanol were detected as main products [31]. Mercury- and platinum-loaded Ti02 favoured formation of carbon and formaldehyde [28,29], Methane was obtained with a high selectivity in the case of palladium-doped Ti02, whereas in the presence of Rh, Au, and Ru metals acetic acid was also produced [30],... 

The coking during propene oligomerization over silica-supported heteropoly acid H3PW12O40 and its palladium-doped form and subsequent catalyst regeneration have been studied using and P MAS NMR. " ... 

Palladium doping (2.1%) of CsHPA (Pd-CsHPA) further improves the catalyst performance upon reuse. The palladium-doped catalyst performed no better than the undoped one, but it can be regenerated with full recovery of both activity and selectivity over five successive runs. Only a small decrease in activity in the first run for Pd-CsHPA compared with undoped CsHPA can be noted, probably because the palladium partly exists as Pd(ll) in the first run, whereas in the subsequent runs it mostly exists as Pd(0) due to reduction of Pd(ll) by the reaction medium. 

In the thermal studies, the reactants were mixed (in the absence of a solvent) with palladium doped, potassium fluoride treated alumina and the mixture heated for four or more hours at temperatures approaching 100 In this portion of the study, we examined the effectiveness of microwave irradiation for enhancing the rate of the reactions. The feasibility of using microwave irradiation to induce organic reactions on solid surfaces in the absence of solvents has been demonstrated previously. As a probe, we investigated the reaction of tolylboronic acid with iodobenzene for various time periods. Table V. 2-Methylbiphenyl was formed readily under a variety of reaction conditions. For convenience, we found it most efficient to simply heat the mixtures for 2 minutes at 100% power. Under these conditions, a small amount of organic material could be observed condensing on the cooler portions of the reaction vessel. 

Ai, M., 2002. Catalytic activity of palladium-doped iron phosphate in the oxidative dehydrogenation of lactic add to pyruvic acid. Applied Catalysis A 232,1-6. 

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