Rhenium ethane

The ability of the rhenium-benzene co-condensate to activate linear- and cyclic- alkanes is quite general. We have co-condensed rhenium atoms with alkane benzene mixtures using the alkanes ethane, propane, butane, 2-methylpropane, neopentane,... 

Figure 4a Summary of the reactions of rhenium atoms with acyclic saturated hydrocarbons. Rhenium atoms were co-condensed with the indicated substrates at -196 °C. (i) Ethane (ii) Propane (iii) n-Butane (iv) Neopentane (v) 2-Methylpropane and (vi) Tetramethylsilane.

F,SCH, Methanesulfonic acid, trifluoro-iridium, manganese and rhenium complexes, 26 114, 115, 120 platinum complex, 26 126 OiFeCgH, Iron, acetyl dicarbonyl (if -cyclopentadienyl)-, 26 239 0,FeN2C2 Hll(, Iron, tricarbonylbis(2-isocy-ano-l,3-dimethylbenzene)-, 26 54 0.iMoNaCHH5-2 C4H ,02, Molybdate 1 -), tricarbonyl(T) -cyclopentadienyl)-sodium, compd. with 1,2-dimethoxy-ethane-(l 2), 26 343 0,NaWC H5-2 C4H ,02, Tungstate(l -), tricarbonyl(ris-cyclopentadienyl)-... 

TRIS(l,2-BIS(DIMETHYLPHOSPHINO)ETHANE)-RHENIUM(I) TRIFLUOROMETHANESULFONATE, [Re(DMPE)3] [CF3SO3] ... 

Tris(l,2-bis(dimethylphosphino)ethane)rhenium(I), [Re(DMPE)3]+ is a simple, symmetrical cation which contains three identical bidentate phosphine ligands. This complex provides a Re(II/I) redox couple with properties that are very convenient for the study of outer-sphere electron transfer reactions.1 Specifically, this couple is stable in both alkaline and acidic media and it exhibits a reversible, one-equivalent redox potential in an accessible region [ °,(II/I) = 565 mV vs. NHE]. Moreover, this complex has been used to obtain information about the biological mechanism of action of 186Re and l88Re radiopharmaceuticals.2,3... 

A. PREPARATION OF TRIS(l,2-BIS(DIMETHYLPHOSPHINO)-ETHANE)RHENIUM(I) TRIFLUOROMETHANESULFONATE FROM DIOXOTETRAKIS(PYRIDINE)RHENIUM(V) TRIFLUOROMETHANESULFONATE... 

Tris(l,2-bis(dimethylphosphino)ethane)rhenium(I) trifluoromethanesulfonate is a white solid which can be oxidized to the purple Re(II) analog. This Re(I) salt is soluble in methanol, ethanol, dichloromethane, acetone, dimethyl sulfoxide (DMSO), and acetonitrile, and insoluble in diethyl ether [N.B. This Re(I) complex is unstable in nitromethane, presumably suffering oxidation to Re(II)]. 

The group 5-7 supported transition metal oxides (of vanadium, niobium, tantalum, chromium, molybdenum, tungsten, and rhenium) are characterized by terminal oxo bonds (M =0) and bridging oxygen atoms binding the supported oxide to the cation of the support (M -0-MSUpport). The TOF values for ODH of butane or ethane on supported vanadia were found to depend strongly on the specific oxide support, varying by a factor of ca. 50 (titania > ceria > zirconia > niobia > alumina > silica). 

A recent and quite original approach to the synthesis of RejX, cluster complexes involves the cocondensation of rhenium atoms, generated from a positive hearth electron-gun furnace, and reactive halocarbons such as 1,2-dibromo- (or dichloro-) ethane. Extraction of the reaction matrix at room temperature with THF gives Re3X9(THF)3 (X = Cl or Br) in yields of 90%.185 This strategy will likely see further developments in the future. 

Figure 2.1 compares the catalytic activities of all of the metals of Group VIII and of rhenium in Group VIIA for ethane hydrogenolysis. Three separate fields represent the metals of the first, second, and third transition series (22,23). The Group IB metals (copper, silver, gold), for which data are not shown, are much less active than the least active of the Group VIII metals (22,23). 

As a result of the higher yields of methane and ethane in the run on the platinum-iridium catalyst, the hydrogen concentration in the recycle gas stream was lower than in the run on the platinum-rhenium catalyst. Consequently, the hydrogen partial pressure at the reactor inlet was also lower. The average hydrogen partial pressures were 15.1 and 16.5 atm, respectively, for the runs on the platinum-iridium and platinum-rhenium catalysts. The difference in hydrogen partial pressure at a fixed total pressure is a consequence of the different compositions of the gaseous products, which, in turn, reflect... 

Figure 5.10 shows that C5+ yields are equivalent for the platinum-rhenium catalyst and the combined catalyst system and about 1.0 to 1.5 vol% higher than for the platinum-iridium catalyst. Methane and ethane yields for the combined catalyst system are higher than those for the platinum-rhenium catalyst but lower than those for the platinum-iridium catalyst. Yields of H2 are about equivalent for the combined catalyst system and the platinum-iridium catalyst and are lower than those for the platinum-rhenium catalyst. Similarly, the yields of C3 and C4 hydrocarbons are about equivalent for the platinum-iridium catalyst and the combined catalyst system but are lower than the yields for the platinum-rhenium catalyst. 

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