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Out with convention! The use of borosalicylic acid, derived from boric and salicylic acids, as the acid promoter in the methoxycarbonylation of ethylene to give methyl propionate has been investigated (see scheme). Not only was moderate catalyst activity observed, but much lower formation of phosphonium salts occurred than with conventional acids.

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Hagg carbide (χ-Fe 5 C 2 ) is considered to be the primary active phase for high-temperature iron-based Fischer− Tropsch synthesis (HTFTS). Hagg carbide may be oxidized to magnetite during FTS depending on the chemical potential of oxygen, μ O , which may be related to the partial pressure of the oxidizing agents, H 2 O or CO 2 . 3Fe 5 C 2 + 26H 2 O → 5Fe 3 O 4 + 6CO + 26H 2 , and 3Fe 5 C 2 + 26CO 2 → 5Fe 3 O 4 + 32CO. Magnetite is believed to be active for the water−gas shift reaction but inactive for the HTFTS, and thus, its formation could subsequently contribute to the loss in the FT activity. An in situ magnetometer was used to follow the oxidation behavior of Hagg carbide by either H 2 O or CO 2 under realistic high-temperature FT process conditions. Hagg carbide is not magnetic at the high temperature used for the FT process, while magnetite is. Thus, the transformation of Hagg carbide to magnetite can be followed by tracking its magnetization and by employing in situ X-ray diffraction, at relevant conditions. The results indicated that the oxidation of Hagg carbide and the concurrent catalyst deactivation at these conditions are strongly dependent on the H 2 O levels present in the reactor. No oxidation was observed at CO 2 levels up to 8 bar, while in agreement with the thermodynamic calculations conducted in this study, H 2 O-induced oxidation was observed at 4 bar during 3 to 20 h exposure. It may be speculated that lower H 2 O levels could also contribute to Hagg carbide oxidation if the exposure times are longer. Magnetite can be transformed back to Hagg carbide upon lowering the H 2 O partial pressure or if H 2 O is removed altogether. This fast reversibility in the phase transformation has also been coupled with an activity gain. More importantly, it has been shown that magnetite may not be solely responsible for the water−gas shift activity during the FTS.