Novel effect of carbon dioxide on catalyst properties. Dimerization of butadiene

Evidence for Platinum(II) Oxo Intermediates in Reactions of (Diphosphine)platinum(II) Carbonate Complexes

“…Previous reports have described reactions of (diphosphine)platinum(II) carbonate complexes with substrates such as carbon monoxide or phosphine that led to Pt(0) species and oxidized substrate. [17][18][19][20] The exact nature of these reactions has not been clearly identified and is complicated by the fact that many of these reactions were run in alcoholic solvents where alcohol/ carbonate equilibria may be occurring, 7 leading to reduction by β-hydrogen elimination from coordinated alkoxide. 21 The present studies offer a more detailed picture of the reduction of platinum carbonates in nonhydroxylic solvents.…”

Selective, high-yield, linear dimerization of 1,3-butadiene catalyzed by dibromobis(triphenylphosphine)nickel and sodium tetrahydroborate and its polymer-bound nickel(0) analog

“…12 High yields of octatrienes were also obtained from butadiene over (PPli3)3Pt under 400 psi of carbon dioxide, but in the absence of carbon dioxide, 4-vinylcyclohexene was formed in 90-97%.12 Similar results were obtained with (PPhs^Pd. 13,14 With bis(7r-allyl)palladium, linear trimers (n-dodecatetraene) and higher oligomers are formed, while bis(x-allyl)nickel converts butadiene to cyclododecatriene, and bis(ir-allyl)platinum gives trimer and tetramer mixtures at higher temperatures.15 When triphenylphosphine is added to -allylpalladium acetate, linear dimerization predominates. 16 Gardner and Wright17 have reported that an 80% yield of octa-1,7-diene can be obtained when platinum salts, such as LiPtCL, were used in formic aciddimethylformamide.…”

Selective conversion of 1,3,7-octatriene to aromatics

“…The dimerization of butadiene to 1,3,7-octatriene is well established and has been the subject of numerous papers (Smutny, 1967;Takahashi et al, 1967;Kohnle and Slaugh, 1969). In a conversion of greater than 80% 1,3,7-octatriene can be obtained.…”