Selective co-oligomerization of 1,3-butadiene and carbon dioxide with immobilzed catalysts

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 1999-10, Vol.146 (1), p.25-36
• Main Authors: Holzhey, Nancy, Pitter, Stephan
• Format: Article
• Language: English
• Subjects: Applied sciences; Carbon dioxide; Co-oligomerization; Copolymerization; Exact sciences and technology; Organic polymers; Palladium catalyst; Physicochemistry of polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/S1381-1169(99)00077-1

Recent results on the heterogeneously catalyzed co-oligomerization of 1,3-butadiene and carbon dioxide are presented. Optimized preparation methods for the reaction of Pd(η 3-C 3H 5)(η 5-C 5H 5) 2 with [( i-Pr) 2P–CH 2]-polystyrene derivative PS-P yield palladium catalysts immobilized on polystyrene support ( PS-01, PS-02, PS-03). Consequently, `leaching' is reduced and catalysts may be re-used several times after a simple separation and cleaning procedure. Additionally, a similar immobilization of palladium complex units on silica is reported. The correlation of the formation of 2-[( E)-ethylidene]-6-heptene-5-olide 1 with process parameters such as temperature, kind of catalyst, and solvent, is presented and discussed in detail. Analytical methods (CP-MAS-NMR, XPS, SEM) were used to determine PS-02 before and after use. XPS data indicate an initial Pd 0 oxidation state. Used PS-02 possesses a changed coordination sphere around the anchored palladium centres which agrees to its different catalytic behaviour.