The gas phase reaction of ethanol conversion to butadiene, which involves dehydration and dehydrogenation of ethanol, was investigated over silica supported catalysts in a tubular reactor.
The catalysts used in the reaction were manufactured by the impregnation method (metal oxide+silica). In the fixed bed reactor the effects of feed flow rate, feed concentration, feed mole ratio ($C_2H_5OH/CH_3$ CHO) and reaction temperature on ethanol conversion, butadiene yield and catalytic activity were experimentally studied. The liquid and gas products were analyzed quantitatively by a gas chromatograph.
In a series of experiments, 2% $Cr_2O_3$-15.3% MgO-$SiO_2$ catalyst showed the highest butadiene yield and gave the optimum reaction conditions as follows.
Reaction temperature : 410-430℃
W/F : 0.144 kg cat.-hr/mol
Butadiene conversion : 88.0%
Butadiene yield : 42.4 wt.%
Using the above results, a scale-up of the process was designed on the basis of 2,000 ton/yr. of butadiene production. As a result of examining the economic feasibility this process will be economically viable in 6 years assuming that the oil price and butadiene price continue to increase at 15%/yr and 15%/yr respectively.