The Use of Rhodium Salts as Catalysts for the Polymerization of Butadiene

Abstract

Nov. 5. 1962 RHODIUM SALTS AS BUTADIENE P O L Y M E R I Z A T I O N C a T A L Y S T S 4145 (iii) A portion of the reactants disappears to give material other than CbHg isomers a t a rate which is nearly independent of time. Evidently both cis and trans isomers participate in this reaction which presumably gives high boiling material.(iv) Beyond the maximum in the concentration of cis-pentadiene, the reaction ck-CHs= CHCH=CHCHa + hv d ~uLEs-CH~=CHCH=CHCHI (10) may account for the decrease in the cis isomer.These results give more direct evidence for the statement made in an earlier section that the general reaction2 is probably rapid when compared to the rates of rotation around the carbon-carbon bonds in the molecule. Reaction 8 may be pic-$2 V tured as proceeding through an excited state (V) which is probably the same as the state which leads to the cis isomer through rotation around the bond between C3 and C4. The latter operation has no energy barrier in the excited state up to an angle of r/214 and its rate may be comparable to the rate of rotation around the bond between CZ and Cp. Since the rate of reaction 8 is observed to be faster than reaction 9, it follows that the former is favored by a suitable configuration in the ground state in the molecules which undergo the process. l5Acknowledgment.-The author wishes to thank Dr. Harold L. Friedman for his advice and encouragement during the course of this work. He is grateful to Drs. J. Kumamoto and J. C. Powers for many helpful discussions.

Highly trans‐1,4‐specific polymerization of 1,3‐butadiene catalyzed by [2,6‐bis{(4S)‐ (−)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine] chromium complex activated with modified methylaluminoxane

“…The trans ‐1,4‐PBD obtained with 1 –MMAO is crystalline and shows two melting points at 78.2 °C (−Δ H m = 154.7 J g −1 ) and 135.7 °C (−Δ H m = 63.0 J g −1 ), while that obtained with 1 –MAO does not show a melting point in DSC measurements. Trans ‐1,4‐PBD is able to be synthesized with several catalyst systems containing transition metals such as lanthanoids,32, 33 titanium,34, 35 vanadium,36, 37 chromium,22 iron,23 cobalt38 and rhodium39, 40 (Table 3). The present 1 –MMAO system is one of the most trans ‐1,4‐specific catalysts for BD polymerization, although its activity is not very high.…”

Controlled and Living Polymerizations Induced with Rhodium Catalysts. A Review

“…Polymerization of butadiene with Rh(III) salts proceeds without an induction period, it is of the zero reaction order with respect to butadiene and of the first order with respect to the catalyst 8 if the catalyst concentration is neither too low nor too high (ca from 1 to 50 mmol/l). The lower catalyst concentration limit occurs owing to the participation of radical polymerization, which is quenched by Rh(III) salt at an increased concentration.…”

“…Evidences for this explanation were obtained from the polymerization kinetics as well as from the polymer structure analysis: the presence of cis-and 1,2-units in the polybutadiene prepared using a low concentration of the Rh salt. The upper concentration limit is ascribed to the formation of oligomeric Rh species in solutions 8,9 . In context with the observed precise trans-stereocontrol of the butadiene polymerization by Rh species, Rinehart et al also examined the cis-to-trans isomerization of pure cis-1,4-PB by RhCl 3 (ref.…”

“…In context with the observed precise trans-stereocontrol of the butadiene polymerization by Rh species, Rinehart et al also examined the cis-to-trans isomerization of pure cis-1,4-PB by RhCl 3 (ref. 8 ). The reaction proceeded to the equilibrium cis/trans content (ca 25% cis-and 75% trans-form) and it was inhibited by butadiene which transforms the isomerization species to the polymerization ones.…”

Emulsion Polymerization

“…In the case of the oligomerization of norbornene, a 'micro-latex' was obtained with an average particle diameter of approximately 10 nm with PdCl 2 as the catalyst and sodium dodecylsulfate as the surfactant. In 1969, Rinehart et al (1962) and Canale et al (1962) independently reported on the .rhodium-catalyzed emulsio.n polymerization of butadiene to a high trans-1,4 polymer utilizing sodium dodecylbenzenesulfonate as the surfactant. Almost ten years later, Entezami et al (1977) showed that trans-and c/s-l^-pentadiene can be polymerized in an emulsion using RhCl 3 as the catalyst and sodium dodecylbenzenesulfonate as the surfactant.…”