Oxidn of ethylene to acetaldehyde - in aq catalyst soln contg cupric chloro-acetate, palladium salt and acetic acid

摘要

In the prepn. of acetaldehyde (I) by direct catalytic liq phase oxidn. of ethylene (II) in presence of O2 in an aq. soln contg. Pd, Cu salt and acetic acid, the catalyst soln. contains CuCl(CH3COO) (III) opt. mixed with CuCl2. Pref. the soln. contains 0.001-0.015 mol/l Pd. Salt; 0.3-1.2 mole/l (III) (or 0.25 - 1.15 mole/l (III) plus 0.05-0.5 mole/l CuCl2) and 15-30 wt. % acetic acid. Oxidn. and catalyst regeneration occur in a single zone and rate of circulation of catalyst soln. can be increased from 5-6 to 16-18 kg/m3/hr. Selectivity is improved with redn. in content of Cl-contg. byprods. from 2-3 to 0.6%. Cu content in the catalyst soln. is 2-3 times lower than conventional soln. and, since O2 and (II) conversions are almost 100%, gas recycle is unnecessary.