Homogeneous redox catalysts based on heteropoly acid solutions: I. Pilot testing of a catalyst and methyl ethyl ketone synthesis

The pilot experiments on methyl ethyl ketone (MEK) synthesis in 2005–2006 were aimed at developing a technology for highly selective n -butylene oxidation with oxygen into MEK in the presence of a new homogeneous catalyst. This catalyst was a chloride-free aqueous solution of Pd(II) + HPA-7′, where HPA-7′ is a vanadium-rich molybdovanadophosphoric acid of modified (non-Keggin) composition with the empirical formula H 12 P 3 Mo 18 V 7 O 85 . For ensuring the explosion and fire safety of the pilot unit, the MEK synthesis process was carried out in two steps conducted in different reactors. The catalyst solution in the pilot plant circulated in a closed loop. The target reaction (step (1)) was performed at 60°C and an n -butylene pressure of 9 bar in a tubular plug-flow reactor 1 in the absence of O 2 . The high oxidation potential of the HPA-7′ solution ensured a high rate of the reaction, which lasted