Selective formation of isoprene via dehydration of 3-methyl-1,3-butanediol over Y2Zr2O7 catalyst

Vapor-phase dehydration of 3-methyl-1,3-butanediol to produce isoprene was investigated over Y2Zr2O7 catalysts prepared by hydrothermal aging at 200 degrees C with various aging times. Removal of residual species such as nitrate and crystallization of Y2Zr2O7 proceeded during the hydrothermal aging. The X-ray diffraction analysis confirmed the progression of the Y2Zr2O7 crystal growth during hydrothermal aging from 0 to 24 h, with no significant change afterward. The hydrothermal aging time of up to 4 h significantly influenced the acid-base properties of the Y2Zr2O7 catalysts, which consecutively affected their catalytic performance. At a reaction temperature of 375 degrees C, the conversion of 3-methyl-1,3-butanediol and the selectivity to isoprene over Y2Zr2O7 catalyst calcined at 900 degrees C were 100 and 82.4% at a time on stream of 10 h, respectively. Reaction mechanisms were also proposed in consideration for the results of dehydration of intermediate unsaturated alcohols.

Automated summary

Vapor-phase dehydration of 3-methyl-1,3-butanediol to produce isoprene was investigated using Y2Zr2O7 catalysts prepared by hydrothermal aging at 200 degrees C. The aging process removed residual species and crystallized Y2Zr2O7. X-ray diffraction analysis confirmed the growth of Y2Zr2O7 crystals during hydrothermal aging up to 24 hours. The acid-base properties and catalytic performance of the catalysts were significantly influenced by the hydrothermal aging time.