Catalyst with nickel/molybdenum mixed oxid

The fust reaction takes place in the vapor phase, between 330 and 360°C, at low pressure (between 03 and 04.106 Pa absolute), in the presence of air and steam in a r-butanol/air/steam ratio of about 1 10 to 15/6 to 12, on a catalyst based on mixed oxides of molybdenum, cobalt, bismuth, iron, nickel, and additions of derivatives of alkaline metals, antimony, tellurium, phosphorus, tungsten, tin, manganese, etc. With residence times of 2 to 3 s, the molar yield of methacrolein exceeds 85 per cent for virtually total once-throngh conversion of r-butanoLThe main by-products formed are... 

The first-stage catalysts for the oxidation to methacrolein are based on complex mixed metal oxides of molybdenum, bismuth, and iron, often with the addition of cobalt, nickel, antimony, tungsten, and an alkaU metal. Process optimization continues to be in the form of incremental improvements in catalyst yield and lifetime. Typically, a dilute stream, 5—10% of isobutylene tert-huty alcohol) in steam (10%) and air, is passed over the catalyst at 300—420°C. Conversion is often nearly quantitative, with selectivities to methacrolein ranging from 85% to better than 95% (114—118). Often there is accompanying selectivity to methacrylic acid of an additional 2—5%. A patent by Mitsui Toatsu Chemicals reports selectivity to methacrolein of better than 97% at conversions of 98.7% for a yield of methacrolein of nearly 96% (119). 

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