A novel route to synthesize SAPO-11 molecular sieves with a high external surface area in the presence of ethylene glycol and supercritical carbon dioxide for 1-octene hydroisomerization to dimethylhexanes

The article proposes a novel and eco-friendly method for synthesizing SAPO-11 in ethylene glycol (EG) and supercritical carbon dioxide (ScCO 2 ). The method incorporates ScCO 2 into EG to decrease the solubility of SAPO-11 precursors in EG and thereby forms a highly supersaturated solution of SAPO-11 precursors. The as-synthesized SAPO-11 possesses smaller particles, a larger external surface area, and a larger number of acid sites than the SAPO-11 synthesized in EG and the SAPO-11 synthesized in water and ScCO 2 , respectively. These advantages of the as-synthesized SAPO-11 endow the corresponding catalyst with superior dibranched isomer selectivity and low cracking selectivity during 1-octene hydro isomerization.