Tanaka catalyst

Fig. 17 Oxyl (top-left) and superoxo (top-right) forms of the Tanaka catalyst. The bottom part of the figure shows the relative orientation of the tpy (short bold line) and anthracene (long bold line) ligand planes.

Figure 6. Structure of the Tanaka catalyst and acid-base reaction of the...

Although there still exist some mechanistic questiorrs and some inconsistencies in theoretical resrrlts from different levels of theory, we summarize here our new theoretical and ejqrerimental studies aimed toward understanding the complicated electrorric and geometric structures of the Tanaka catalyst, and we discuss new directiorrs for kinetic and mechanistic... 

Figure 7. Proposed mechanism of water oxidation by the Tanaka catalyst based on B3LYP/LANL2DZ calculations.

As it can be seen in Fig. 12.8, the kinetic of CO adsorption on Pt based catalysts did not change when the adsorption and the pre-treatment were performed at higher temperature. As expected, the thermokinetic parameter firstly increases to reach a maximum and then slowly decreases showing that CO is almost completely irreversibly adsorbed on the surface of Pt-based catalyst. The amount held by the strong chemisorption sites at a certain adsorption temperature gives valuable information about the catalysts behaviour towards poisoning. Indeed, as deduced from volumetric data, 93 and 85 % of the total amount of CO was irreversibly adsorbed on Pt/C Tanaka catalyst for the powder pre-treated at 25 °C and CO adsorbed at 30 °C, and for the same sample pre-treated at 100 °C and CO adsorbed at 80 °C, respectively. Similar... 

Interestingly, Tanaka (ref. 27) has reported the cooxidation of cyclohexane with acetaldehyde in the presence of a Co(OAc)2 catalyst in acetic acid at 90 °C (3). Adipic acid was obtained in 73% selectivity at 88% cyclohexane conversion. 

Uenishi, M., Tanigushi, M., Tanaka, H. et al. (2005) Redox behavior of palladium at start-up in the perovskite-type LaFePdO automotive catalysts showing a self-regenerative function, Appl. Catal. B 57, 267. 

Some information about how the carbonyl group adsorbs onto the catalyst surface has been determined and is summarized by Tanaka.169 On the basis... 

Tanaka and Kakiuchi (6) proposed catalyst activation via a hydrogen donor such as an alcohol as a refinement to the mechanism discussed by Fischer (7) for anhydride cured epoxies in the presence of a tertiary amine. The basic catalyst eliminates esterification reactions (8). Shechter and Wynstra ( ) further observed that at reaction conditions BDMA does not produce a homopolymerization of oxiranes. 

Tanaka et al.28 have synthesised a series of (S)-chiral Schiff bases as the highly active (yield 69-99%) and enatioselective (ee 50-96%) catalysts in the reaction of addition of dialkylzinc to aldehydes. The stereochemistry of the asymmetric addition was suggested. In a transition state when S-chiral Schiff base was used as chiral source, the alkyl nucleophile attacked Re face of the activated aldehyde and formed the R-configuration alkylated product [13]. 

Dynamic Mechanical Properties. The dynamic mechanical properties of branched and linear polyethylene have been studied in detail and molecular interpretation for various transitions have already been given, although not necessarily agreed upon in terras of molecular origin.(52-56) Transitions for conventional LDPE (prepared by free radical methods) when measured at low frequencies, are located around +70°C, -20°C and -120°C and are assigned to o, 5, and y transitions respectively. (53) Recently Tanaka et al. have reported the dynamic mechanical properties for a sample of HB which was also prepared by anionic polymerization, but contrary to our system the hydrogenation of the polybutadiene was carried out by a coordinate type catalyst.(12) The transitions reported for such a polymer at 35 Hz are very similar to those of LDPE.(12)... 

Domen, K., Kudo, A., Tanaka, A., and Onishi, T., Overall photodecomposition of water on a layered niobate catalyst, Catal. Today, 8, 77,1990. 

Nakamura, J., Tanaka, K., and Toyoshima, 1.1987. Reactivity of deposited carbon on cobalt-alumina catalyst. J. Catal. 108 55-62. 

In a related observation, reported by Tanaka et al. (81), the copper(II) complex Cu(tpa)2+ (tpa = tris[(2-pyridyl)methyl] amine) was shown to serve as a catalyst for the electrochemical reduction of nitrite to N20 and traces of NO in aqueous solution. NO and/or a copper nitrosyl complex would appear to be the likely intermediates in this process (81a). 

H. Sasai, T. Suzuki, N. Itoh, K. Tanaka, T. Date, K. Oka-mura, M Shibasaki, Catalytic Asymmetric Nitroaldol Reaction Using Optically Active Rare Earth BINOL Complex Investigation of the Catalyst Structure, J. Am Chem Soc 1993,115,10372-10373. 

Tanaka et al. (152) demonstrated that a chiral copper alkoxide could be used substoichiometrically to deliver MeLi to an enone in conjugate fashion. The precatalyst is formed from amino alcohol 221, MeLi and Cul, Eq. 123a. Under stoichiometric conditions, this catalyst mediates the conjugate addition of MeLi to the macrocyclic enone, affording muscone in 91% ee. Lower enantioselectivity is observed using a substoichiometric amount of 222 (0.5 equiv), affording a 79% yield of muscone in 76% ee, Eq. 123b. These selectivities are attained by portion-wise addition of the substrate and MeLi to the alkoxy-cuprate. This catalyst also exhibits a complex nonlinear effect (78, 153). 

T. Hayashi, K. Tanaka, and M. Haruta, Selective vapor-phase epoxidation of propylene over Au/Ti02 catalysts in the presence of oxygen and hydrogen, J. Catal. 178(2), 566-575 (1998). 

M. Okumura, K. Tanaka, A. Ueda, and M. Haruta, The reactivities of dimethylgold(lll)beta-diketone on the surface of Ti02—A novel preparation method for Au catalysts. Solid State Ionics 95(1-2), 143-149 (1997). 

H. Tanaka, S.-I. Ito, S. Kameoka, K. Tomishige, and K. Kunimori, Promoting effect of potassium in selective oxidation of CO in hydrogen-rich stream on Rh catalysts, Catal. Commun. 4, 1-4... 

Shimizu, K Takamatsu, M Nishi, K Yoshida, H Satsuma, A Tanaka, T Yoshida, S Hattori, T. Alumina-supported gallium oxide catalysts for NO selective reduction Influence of the local structure of surface gallium oxide species on the catalytic activity, J. Phys. Chem., B, 1999, Volume 103, Issue 9, 1542-1549. 

Tanaka et al. have recently reported low-temperature active PROX catalysts consisting of FeOx/Pt/Ti02 [53]. They studied the mechanism of selective CO... 

Kobayashi J, Kitaguchi K, Tanaka H, Tsuiki H, Ueno A (1987) Photogeneration of hydrogen from water over alumina supported ZnS-CdS catalyst. J Chem Soc Faraday Trans 1 83 1395-1404... 

This maximum in the entrainment flux observed by Wen and Tanaka is in some agreement with the work of Baeyens et al. [15]. Baeyens et al. worked with equilibrium fluidized catalytic cracking (FCC) catalyst powder with varying additions of fines. They found that below a critical particle size, entrainment rates leveled off and noted that this reflected the point where Van der Waals forces were in balance with gravitational forces. For their systems, this critical particle size was found to be approximated by the expression... 

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