Molecular modeling of ring-chain equilibria for the ring-opening cross-metathesis of cis,cis-1,5-dimethyl-cycloocta-1,5-diene with ethylene at T=298.15 K

Density functional theory study of ring-chain equilibria for the cross-metathesis of cyclohexene and cis,cis-cycloocta-1,5-diene with functionalized olefins

“…It is seen that the agreement is reasonable. The calculated [11] and experimentally [22] obtained values of D H for conversion of COD into trans-polybutadiene at T = 298 K are À40.1 and À33.0 kJ AE mol À1 , respectively.…”

“…Table 1 shows the calculated thermodynamic parameters of cyclic and linear molecules for the cross-metathesis of CH and COD with DCE, DCB and ethylene at T = 298.15 K. The thermodynamic parameters have been calculated only for the all trans-isomer products. It has been shown that the formation of trans-isomers is more preferable compared to cis-compounds [11]. Table 2 presents the calculated standard free energy (DG), enthalpy (DH) and entropy (DS) differences of ring-linear molecules equilibrium for the ring-opening cross-metathesis of CH and COD with olefins at T = 298.15 K. It is seen that CH can open via crossmetathesis with thermodynamically highly unstable cis-DCE to yield the ring-opened trans-trans-1,8-dicarbomethoxy-octa-1,7-diene (scheme 2).…”

“…[9]. We have studied the distributions of cyclic and linear products for the ring-opening cross-metathesis of cis,cis-cycloocta-1,5-diene (COD) and cis,cis-1,5-dimethyl-cycloocta-1,5-diene with ethylene (ethenolysis) using the ab initio approach [10][11][12]. ROMP of cycloolefins in the presence of functionalized olefins as CTAs yields end-functionalized polymers (telechelics) (scheme 1).…”

Olefin Metathesis Reaction in Rubber Chemistry and Industry and Beyond

“…Tlenkopatchev and his co-workers reported the molecular modeling of the distributions of cyclic and linear products in the ring-opening cross-metathesis of cis , cis -1,5-dimethyl-cycloocta-1,5-diene, cis , cis -1,6-dimethyl-cycloocta-1,5-diene, and cis , cis -cycloocta-1,5-diene with ethylene at 298.15 K using the B3LYP/6-31G­(d,p) level of theory. , It was revealed that the ring–chain equilibrium constants were dependent on the nature of cyclic diene, in agreement with the reported experimental data by others. The computational modeling of ring–chain equilibria for the ring-opening cross-metathesis of cyclohexene with 1,2-dicarbomethoxy-ethylene, 1,4-dicarbomethoxy-but-2-ene (DCB), and ethylene demonstrated that the cyclohexene and ring-opened products tended to the thermodynamically stable six-membered ring, and the carbonyl-containing olefins could drive the cross metathesis with cis , cis -cycloocta-1,5-diene to the ring-opened products …”