Eg. Chepaikin et al., CATALYTIC CARBONYLATION OF ETHYLENE IN THE PRESENCE OF THE PD(ACAC)(2)-M-PH(2)PC6H4SO3NA(H)-ACOH SYSTEM, Russian chemical bulletin, 43(3), 1994, pp. 360-363
Catalytic systems based on phosphine complexes of palladium have been
developed for synthesizing propionic acid (monocarbonylation) and alte
rnating (1:1) ethylene-carbon monoxide copolymers, i.e., polyketones (
polycarbonylation). m-(Diphenylphosphino)benzenesulfonic acid or its s
odium salt were used as ligands. Monocarbonylation proceeds at atmosph
eric pressure in dioxane or acetic acid solvents. Under high pressure,
the reaction pathway can change from monocarbonylation, which occurs
in the presence of the sodium salt of the ligand, to polycarbonylation
when the sodium ion at the sulfo group is completely replaced by a pr
oton. This change in reaction selectivity is observed when the process
is performed in acetic acid. When the ligand is present both in the a
cid and the neutral form, products of di- and oligocarbonylation are f
ormed along with propionic acid and the polyketone. These products wer
e characterized by H-1 and C-13 NMR spectra as alternating keto acids
C2H5(COCH2CH2)(n)COOH, where n = 1 divided by 3. Kinetic equations wer
e derived for the selective synthesis of propionic acid and polyketone
s.