A High ( Z )/( E ) Ratio Obtained During the 3-Hexyne Hydrogenation with a Catalyst Based on a Rh(I) Complex Anchored on
- PDF / 322,709 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 64 Downloads / 166 Views
A High (Z)/(E) Ratio Obtained During the 3-Hexyne Hydrogenation with a Catalyst Based on a Rh(I) Complex Anchored on a Carbonaceous Support Domingo A. Liprandi • Edgardo A. Cagnola Jose´ F. Paredes • Juan M. Badano • Mo´nica E. Quiroga
•
Received: 14 November 2011 / Accepted: 13 December 2011 / Published online: 23 December 2011 Ó Springer Science+Business Media, LLC 2011
Abstract The (Z)/(E) ratio was analyzed for the 3-hexyne semi-hydrogenation at 275, 290 and 303 K. [RhCl(NH2 (CH2)12CH3)3] pure and supported on a carbonaceous material were used as catalysts. The supported complex showed high values of conversion and selectivity, and its behaviour was much better than the Lindlar catalyst used as a reference. Keywords (Z)/(E) Ratio 3-Hexyne partial hydrogenation Rhodium complex Carbonaceous support
1 Introduction The synthesis and manufacture of food additives, flavors and fragrances, as well as pharmaceutical, agrochemical
D. A. Liprandi E. A. Cagnola (&) J. F. Paredes M. E. Quiroga Quı´mica Inorga´nica, Departamento de Quı´mica, Facultad de Ingenierı´a Quı´mica (UNL), Santiago del Estero 2829, S3000AOJ Santa Fe, Argentina e-mail: [email protected] D. A. Liprandi e-mail: [email protected] J. F. Paredes e-mail: [email protected] M. E. Quiroga e-mail: [email protected] J. M. Badano M. E. Quiroga INCAPE, Instituto de Investigaciones en Cata´lisis y Petroquı´mica, (FIQ-UNL, CONICET), Santiago del Estero 2654, S3000AOJ Santa Fe, Argentina e-mail: [email protected]
and petrochemical substances, examples of fine and industrial chemicals, are closely related to selective alkyne hydrogenation [1, 2]. Regarding non-terminal alkyne semi-hydrogenation, the main goals are to avoid hydrogenation to single bond and to give priority to the highest possible conversion and selectivity to the (Z)-alkene [3–5]. The control over conversion and selectivity of a catalytic reaction can be exerted in different ways, e.g.: by varying (a) the active species or (b) the support, and/or by adding (c) a promoter/ a poison/a modifier, and finally, and not less important, modifying the reaction temperature. Examples of the factor (b) are: mesoporous [6] and siliceous [7] materials, a pumice [8], carbons [9], and hydrotalcite [3]. Cases of factor (c) are the typical Lindlar catalyst (palladium heterogenized on calcium carbonate poisoned by lead acetate or lead oxide, Pd–CaCO3–Pb) [10] and the presence of quinoline and triphenylphosphine [11, 12]. Research on the factors (a) and (c) include bi-elemental systems such as Ni–B, Pd–Cu, etc. [13–19]. An example of the effect of the reaction temperature is a paper by Choi and Yoon [20], who found that the selectivity to (Z)-alkene increases when the temperature decreases using a Ni catalyst. On the other hand, transition metal complexes are a group of substances widely used as catalysts for homogeneous and heterogeneous hydrogenation reactions. In the context of the previous paragraph they could be considered as a new active species or as a metal conditione
Data Loading...
