Formation of 1,3-butadiene from ethanol in a two-step process using modified zeolite-β catalysts
•Cu\SiO2 presents an active and long term stable catalyst for dehydrogenation of ethanol to acetaldehyde.•Selectivity towards 1,3-butadiene increases with increasing effective acidity.•Selectivity towards the dehydration products ethylene and diethyl ether and ethanol conversion decreases with rising acidity.
Catalysts for the selective formation of 1,3-butadiene out of ethanol in a continuous two-stage gas-phase fixed bed reactor setup were developed. In the first stage, 20% acetaldehyde yield was aspired. This mixture was directly fed into the second stage facilitating enhanced selectivity to 1,3-butadiene. In the first stage, Ag\SiO2 and Cu\SiO2 were studied. Especially the copper based catalyst proved to be a selective and long-term stable system. In the second stage we tested different zeolite-β based catalyst systems which were modified in terms of their acidic and basic behaviour. We were able to reach 1,3-butadiene selectivities up to 72% at rather low temperatures of 573 K. Furthermore we could draw a direct correlation between the catalyst’s acidic and basic properties and their catalytic performance. The physical properties were analysed via X-ray diffraction, nitrogen physisorption, TGA–DSC and HRTEM. The chemical composition was determined by ICP-AES and SEM–EDX measurements. The investigation of the acidic and basic properties was realized by pyridine adsorption infrared spectroscopy and temperature programmed desorption with ammonia and carbon dioxide, respectively.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (141 K)Download as PowerPoint slide
Journal: Applied Catalysis A: General - Volume 514, 25 March 2016, Pages 192–202