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Alkynes Carbonylation Reactions in Solutions of Palladium Complexes as a New Class of Oscillatory Processes

“…First, it is connected with the proximity of the systems (palladium compounds as catalyst; methanol and acetone as solvents) to these ones, in which we had found oscillations in the earlier works [14][15][16][17]. Second, in system of MA and SA synthesis it is revealed, as we believe, the phenomenon of bistability, and from the literature it is known, that in the systems having of bistability, realization of transition to self-oscillations is quite possible.…”

“…2 are close to that were observed by us for other systems including PhA, MAc and DMEC as substrates. It can testify to the common features for these systems of the reaction mechanisms, which have offered as an explanation of oscillations occurrence in the systems with PhA and MAc [14][15][16] (for example, HPdI participation in the process, or interruption of a chain of steps by an oxidant formed during the process-the availability of a feedback).…”

“…Further it has been shown, that the reaction of oxidative carbonylation of phenylacetylene (ethynylbenzene) (PhA) [14,15], methylacetylene (1-propyne) (MAc) [16] and dimethylethinylcarbinol (2-methyl-3-butyn-2-ol) (DMEC) [17] in a system PdI 2 -KI-MeOH-O 2 with the formation of mainly a, b-non-saturated acids diesters proceeds in an oscillatory mode (change of E Pt , pH, and reaction rate). In other catalytic systems (PdBr 2 -LiBr) we found the chaotic oscillations by using of PhA, and new oscillatory reaction of PhA and MAc oxidative carbonylation to phenylmaleic (3-phenyl-2,5-furandione) and citraconic (3-methyl-2,5-furandione) anhydrides, accordingly, in the system PdBr 2 -LiBr-CH 3 COCH 3 -H 2 O, O 2 being used as an oxidant [18].…”

Oscillatory carbonylation of phenylacetylene in the absence of externally supplied oxidant

“…This theory is further supported by larger pH drops reported when non-dried catalyst solutions are used, which are suppressed and delayed in pre-dried solutions [12]. The presence of water may initiate a cascade of reactions, including formation of Pd(I) species, which are thought to be active catalysts in the oscillatory process [7,14]. Furthermore, unstable methyl iodide that decomposes to iodine and ethane, can account for formation of an oxidizing agent (i.e.…”

“…One such example is the palladium-catalyzed oxidative carbonylation of acetylenes to esters and carboxylic acids [5,6]. The oxidative carbonylation of phenylacetylene (PCPOC reaction) using PdI 2 , KI, O 2 and NaOAc in methanol was shown to display oscillations in pH, redox potential and the rate of consumption of a CO-O 2 gas mixture [6,7]. Substrates such as methylacetylene and 2-methyl-3-butyn-2-ol display similar oscillatory behavior [8].…”