Preparation of Ni-MCM-41 by equilibrium adsorption — Catalytic evaluation for the direct conversion of ethene to propene

Ni-MCM-41 has been prepared by equilibrium adsorption of different nickel precursors. Nickel citrate and nickel nitrate gave the most active catalysts for the direct transformation of ethene into propene above 250 °C at atmospheric pressure. The maximal ethene conversion at 400 °C was 36% while propene selectivity reached 45%. Analysis of product formation spectra at different temperatures, residence times and inlet compositions revealed reaction kinetics consistent with a sequence of ethene dimerization, positional butene isomerization and propene retro-metathesis.

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► Equilibrium adsorption gave active catalysts for the ethene to propene reaction.
► Maximal propene selectivity was 45% combined with an ethene conversion of 36%.
► Only minor amounts of byproducts (ethane, iso-butene, and hexenes) were formed.
► Reaction network: ethene dimerization, butene isomerization, and propene retro-metathesis.
► Moderate catalyst deactivation at 375 °C: conversion drop from 36 to 25% in 55 h.