Carbon Dioxide → Propylene Oxide

Participants

Reaction Steps

A 100 mL Parr reactor equipped with a magnetic stir bar is charged with 34 grams of methanol, 200 mg. of 2,6-lutidine and 250 mg. of Ts-1 titanium silicalite containing 2.1 weight % Ti (calcined at 540-550° C. before use). After stirring for several minutes at ambient temperature, 8 grams of 30% aqueous hydrogen peroxide is added. The closed reactor is then charged with 14 grams of propylene from a Hoke pressure vessel using 400 psig of nitrogen. The reactor is heated at 40° C. for 30 minutes and cooled to 20° C. using an ice bath. The gasses from the reactor are vented into a gas bag. The reactor is pressurized to 400 psig with nitrogen and the gasses vented into another gas bag. The gas bags are analyzed by GC for oxygen, propylene oxide, propylene and CO2. The volumes of the bags are measured using a wet test meter. The liquid phase is analyzed by GC for oxygenated products using acetonitrile as a standard and by LC for carboxylic acids. The hydrogen peroxide conversion is measured by reaction of an aliquot of the recovered liquid with sodium iodide and titration with sodium thiosulfate. The above reaction gave propylene oxide and propylene glycol monomethyl ether isomers in 98.5 and 0.8% selectivity, respectively. The selectivities were based on observed products on a propylene basis. The hydrogen peroxide conversion was 74%.

Provenance & Evidence