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Ru preparation

It is known that chlorine acts as severe poison for NH3 synthesis [20,21]. Hence recent kinetic studies used chlorine-free Ru precursors like Ru3(CO)i2 [8,22] or Ru(N0)(N03)3 [7]. In addition to chlorine, the presence of sulphur was found to poison Ru catalysts. Fig. 2A demonstrates that both poisons may originate from the Ru precursor. The binding energies for the Cl 2p peak and of the S 2p peak observed for Ru prepared form RUO3 are typical for chloride and sulfide anions, respectively [23]. Ru prepared from Rus(CO)i2 was found to have a significantly higher purity. As shown in fig. 2B, sulphur and chlorine impurities can also originate from the support. The XPS data of MgO with a purity of 98 % reveal the presence... [Pg.320]

The calculation of the mean and standard deviation in Chapter 3 can be viewed in terms of the linear model yu = /30 + ru. Prepare a sums of squares and degrees of freedom tree (Figure 9.2) for this model and the nine data points of Section 3.1. How do you interpret the fact that SScorr = SSr = SSpf3 Why are DFfaa and DFlot equal to zero ... [Pg.156]

Glyoxylic acid (CHOCOOH), used in the preparation of fine chemicals (e. g., vanillin and penicillin), is prepared industrially by oxidation of glyoxal with nitric acid. An attempt was made to replace this stoichiometric process by oxidation of glyoxal with air on platinum catalysts [57-59]. In a first series of experiments, catalysts containing different platinum metals (Pt, Ir, Pd, Rh, Ru) prepared on the same active carbon and with the same particle size (1-2 nm) were compared. The initial rate of reaction increased in the sequence 0 = Ru < Rh < Pd < Ir < Pt, which is similar to that of the redox potentials of these elements. [Pg.497]

The influence of CO2 pressure on catalytic activity and product distribution of the aqueous core of the microemulsion droplet with different nanoparticles guests (Pd and Ru) prepared in situ was investigated by varying the pressure of CO2 while keeping the hydrogen pressure constant (Fig. 12.4) [48]. [Pg.396]

Transition metals can be activated by alloying with positive charges. Raney Ru prepared by the Al-Ru alloy has the higher activity than that of pure Ru in terms of the activity per unit area. The activity is even higher with the addition of K. The catalyst has activity even at 373K. Raney Ru is also very active when CsNOs acts as a promoter. ... [Pg.58]

Transition metals are also activated by alloying with electropositive metals. Raney Ru prepared from Ru-Al alloy is more active than pure Ru in terms of specific activity per surface of Ru, suggesting promotion by residual A1 remaining after leaching. It is further activated by the addition of metallic potassium to give a highly active catalyst which works even at 373 K [84]. CsNOa promoted Raney Ru is also very active [85, 86]. [Pg.113]

The methodology used in the preparation of RU 486 (84) and other ll -steroids is shown. Conjugate addition of a cuprate reagent to the a,P-unsaturated epoxide (85) provides the liP-substituted steroid (86) stereospecificaHy (131). Subsequent steps lead to the synthesis of RU 486 (84). [Pg.218]

Bimetallic Complexes. There are two types of bimetaUic organometaUic thorium complexes those with, and those without, metal—metal interactions. Examples of species containing metal—metal bonds are complexes with Ee or Ru carbonyl fragments. Cp ThX(CpRu(CO)2), where X = Cl or 1, and Cp7Th(CpM(CO)2), where M = Ee or Ru, have both been prepared by interaction of CP2TI1X2 or Cp ThCl [62156-90-5] respectively, with the anionic metal carbonyl fragment. These complexes contain very polar metal—metal bonds that can be cleaved by alcohols. [Pg.43]

Stmcture (72) exemplifies the C-4 derivatives prepared by these routes. From this class of monobactams, RU-44790 [110012-78-7] (72, R = FI, =... [Pg.70]

The tetrahydropyranyl ether, prepared from a phenol and dihydropyran (HCl/EtOAc, 25°, 24 h) is cleaved by aqueous oxalic acid (MeOH, 50-90°, 1-2 h). Tonsil, Mexican Bentonite earth, HSZ Zeolite, and H3[PW,204o] have also been used for the tetrahydropyranylation of phenols. The use of [Ru(ACN)3(triphos)](OTf)2 in acetone selectively removes the THP group from a phenol in the presence of an alkyl THP group. Ketals of acetophenones are also cleaved. ... [Pg.261]

One of the most dramatic developments in the chemistry of N2 during the past 30 years was the discovery by A. D. Allen and C. V. Senoff in 1965 that dinitrogen complexes such as [Ru(NH3)5(N2)1 could readily be prepared from aqueous RUCI3 using hydrazine hydrate in aqueous solution. Since that time virtually all transition metals have been found to give dinitrogen complexes and several hundred such compounds are now characterized.Three general preparative methods are available ... [Pg.414]

Ruthenium and osmium have no oxides comparable to those of iron and, indeed, the lowest oxidation state in which they form oxides is -t-4. RUO2 is a blue to black solid, obtained by direct action of the elements at 1000°C, and has the rutile (p. 961) structure. The intense colour has been suggested as arising from the presence of small amounts of Ru in another oxidation state, possibly - -3. 0s02 is a yellowish-brown solid, usually prepared by heating the metal at 650°C in NO. It, too, has the rutile structure. [Pg.1080]

Flaving the d s configuration, the elements of this triad are able to conform with the 18-electron rule by forming mononuclear carbonyls of the type M(C0)5. These are volatile liquids which can be prepared by the direct action of CO on the powdered metal (Fe and Ru) or by the action of... [Pg.1104]

The TiVS) coordination of thiophene was proposed for [(ri -Cp)Ru(PPh3)2(Ti -C4H4S)]" " prepared from [CpRu(PPh3)2Cl], thiophene, and AgBp4 (76JA689,... [Pg.23]

Kiindig et al. recently applied the same perfluoroaryldiphosphonite ligand to the preparation of a cationic Ru catalyst 14 [20] (Scheme 1.27, Table 1.11). This catalyst also promotes the Diels-Alder reaction of a-bromoacrolein and cyclopenta-diene, although this Diels-Alder reaction is slower than that catalyzed by the analogous cationic Fe complex 13, and gives the cycloadducts with lower enantioselec-tivity (Fe 97% ee, Ru 92% ee). [Pg.21]


See other pages where Ru preparation is mentioned: [Pg.151]    [Pg.474]    [Pg.586]    [Pg.140]    [Pg.110]    [Pg.440]    [Pg.151]    [Pg.474]    [Pg.586]    [Pg.140]    [Pg.110]    [Pg.440]    [Pg.2704]    [Pg.486]    [Pg.151]    [Pg.218]    [Pg.177]    [Pg.277]    [Pg.47]    [Pg.319]    [Pg.418]    [Pg.1076]    [Pg.1081]    [Pg.1091]    [Pg.1095]    [Pg.1097]    [Pg.1097]    [Pg.1105]    [Pg.168]    [Pg.170]    [Pg.171]    [Pg.173]    [Pg.177]    [Pg.177]    [Pg.149]    [Pg.149]    [Pg.5]    [Pg.198]    [Pg.199]    [Pg.200]    [Pg.204]    [Pg.204]   
See also in sourсe #XX -- [ Pg.585 ]

See also in sourсe #XX -- [ Pg.378 ]

See also in sourсe #XX -- [ Pg.378 ]




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Prepared by Electrochemical Ru Deposition

Prepared by Spontaneous Ru Deposition

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