The partial oxidation of methane to synthesis gas (syngas, CO + H,)

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La 1−x A x Fe 0.8 Co 0.2 O 3−␦ (A = Ca, Sr, Ba) perovskite powders were synthesized to attain the desired properties of high O 2 flux and stability under reducing conditions. Steady-state oxygen permeation rates for La 1−x A x Fe 0.8 -Co 0.2 O 3−␦ perovskite membranes in nonreacting experiments with air on one side and helium on the other side of the membrane were in the order A x = Ba 0.8 > Ba 0.6 > Ca 0.6 > Sr 0.6 . Partial oxidation of methane to syngas (CO + H 2 ) was performed in a dense La 0.2 Ba 0.8 Fe 0.8 Co 0.2 O 3−␦ membrane reactor at 850°C in which oxygen was separated from air and simultaneously fed into the methane stream. The reducing atmosphere affected the membrane reactionside surface while barium enrichment occurred on the airside surface. Oxygen continuously transported from the air side appeared to stabilize the membrane interior, and the reactor was operated for up to 850 h.

The homogeneous catalyzed addition of ethyl diazoacetate to olefins utilizing (trialkyl phosphitejcopper-(I) chloride complexes was studied. The systematic changes in the isomeric cyclopropane product distribution as a function of the steric bulk of the ligand on copper proves the intermediacy of a carbene-metal-olefin complex in the irreversible cyclopropane-forming step. The direction of the steric effect afforded information on the stereochemistry of the excited complex. As a model system for general homogeneous metal .

The mechanism of the palladium-catalyzed carbomethoxylation of bromobenzene to methyl benzoate in the presence of methanol and triethylamine has been investigated with Cylindrical Internal Reflectance Fourier Transform Infrared Spectroscopy (CIR-FTIR). The synthesis of the proposed catalytic intermediate Pd(Br)(C6H5)(P(C6H5)3)2 (1) was carried out, and the reaction of this species with CO to form Pd(Br)(COC6H5)(P(C6H5)3)2 (3) was confirmed. Both complexes were characterized by IR and 31P and NMR spectroscopy. The stability of 3 in the absence of CO suggests that the carbonylation of 1 is irreversible; its stability in the presence of triethylamine establishes that reductive elimination of benzoyl bromide is not facile. In the absence of CO, the conversion of 3 to methyl benzoate was found to be rapid when both methanol and triethylamine were present, but very slow in the presence of methanol alone. A series of experiments in which 3 was allowed to react with methanol and a variety of amines in the absence of CO demonstrated a direct relationship between the rate of reaction and the amine basicity. These observations point to a mechanism in which methanol is initially deprotonated by the amine, and the methoxide ion thus produced attacks the benzoyl complex directly yielding methyl benzoate. When reaction of the benzoyl complex with methanol and triethylamine was carried out with bromobenzene also present, regeneration of 1 was observed via CIR-FTIR and confirmed by IR and proton NMR spectroscopy. The carbomethoxy species, Pd(Cl)(C02CH3)(P(C6H5)3)2, was shown to be stable in the presence of bromobenzene, triethylamine, and methanol at 90 °C, suggesting that this complex is not an active catalytic intermediate. These experiments substantiate the mechanism in Figure 8.

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