Synthesis of higher alcohols from syngas over Zn–Cr–K catalyst in supercritical fluids

An investigation was carried out on the selective synthesis of higher alcohols from syngas in a supercritical fluid (a mixture of C10–C13 alkanes) by using a fixed bed reactor. Experiments were conducted over Zn–Cr–K catalyst in the temperature range of 360–400°C, a partial pressure of syngas of 7.5 MPa and a partial pressure of supercritical medium of 1.78 MPa. Comparison of results in the gas phase with those in the supercritical phase indicated that CO conversion was higher in the supercritical phase reaction. Alcohol selectivity decreased slowly with increasing temperature in the supercritical phase reaction but decreased rapidly in the gas phase reaction, due to the special properties of supercritical fluids (SCF). Product distributions were different in both reaction phases. The introduction of the supercritical medium promoted carbon chain growth and the content of C2+OH was increased. The product distribution features with high methanol content of the gas phase synthesis were changed.