Hydrogenolysis glycerol

In order to improve the selectivity toward the formation of 1,3-PDO, we studied the influence of metal salt additives. While the addition of calcium or copper salts exhibited a moderate influence, the presence of iron salts played a significant role on the rate and selectivity of the reaction (Figure 35.1). The metal additives reduced noticeably the activity of the rhodium catalysts suggesting that they acted as a surface poison, but they modified the selectivity of the glycerol hydrogenolysis, probably through selective diol chelation. 

Table 11.2 Glycerol hydrogenolysis over heterogeneous catalysts in various conditions.a>...

Glycerol hydrogenolysis has also been illustrated over transition metals impregnated on silica. Some metals, such as Co and Pt, appear inactive for glycerol conversion, while others, such as Rh, Pd, Ir and, especially, Ru are active but lack the... 

Amada Y, Shinmi Y, Koso S, Kubota T, Nakagawa Y, Tomishige K. Reaction mechanism of the glycerol hydrogenolysis to 1,3-propanediol over Ir-ReOx/SiC>2 catalyst. Appl Catal B Environ. 2011 105 117-27. 

Miyazawa. T K. Kunimori K. Tomishige. Glycerol hydrogenolysis in aqueous solution over ru/c+ an ion exchange resin and its reaction mechanism. Prepr. Pap.—Am. Chem. Soc., Div. Fuel Chem. 2006, 51, 530-531. 

Wang S, Yin K, Zhang Y, Liu H (2013) Glycerol hydrogenolysis to propylene glycol and ethylene glycol on zirconia supported noble metal catalysts. ACS Catal 3(9) 2112-2121... 

Fig. 2 Reaction mechanism of the glycerol hydrogenolysis [5]. (a) Dehydration + hydrogenation, (b) Dehydrogenation + dehydration + hydrogenation. Reprinted from RSC [5]...

Therefore, in order to obtain 1,5-PeD selectively, the multi-step method has been reported (4) [25]. This system is composed of three separated steps including dehydration of THFA to dihydropyran, hydration of dihydropyran to 5-hydroxyvaleraldehyde, and hydrogenation of 5-hydroxyvaleraldehyde to 1,5-PeD. The system requires the isolation and purification of the intermediates and the overall yield was 70%. Hydrogenolysis of THFA to 1,5-PeD also seems to be simple judging from the reaction formula (3), just like the case of the glycerol hydrogenolysis however, the selective synthesis of 1,5-PeD from THFA had not been realized. 

An interesting point is that the catalysts effective in glycerol hydrogenolysis were applied to the hydrogenolysis of THFA to 1,5-PeD. Silica- or carbon-supported rhodium catalysts modified with Re, Mo, or W show high activity and selectivity [38—44], while commercial hydrogenation catalysts such as Ru/C, copper chromite, and Raney Ni show much lower activity and selectivity (Table 1). In... 

Fig. 3 Comparison of the catalytic the performances in the glycerol hydrogenolysis over modified Rh/Si02 [33]. Reaction conditions glycerol 4 g, water 16 g, Rh-M0 j/Si02 (M/Rh = 0.25) 0.15 g, F(H2) = 8 MPa, r = 393 K, / = 5 h. Re/Rh = 0.5, r = 1 h. PrD propanediol, PrOH propanol. Degradation ethylene glycol + ethanol + methanol + methane. Reprinted with permission from...

Fig. 9 Effect of Re amount over Ir-ReO /Si02 in glycerol hydrogenolysis [46]. Reaction conditions glycerol 4 g, water 2 g, Ir-ReO /SiOj 0.15 g. H2SO4 (H /Ir = 1), P(H2> = 8 MPa, T = 393 K, / = 12 h. Reprinted with permission from Elsevier [46]...

It is not easy to find excellent bimetallic catalysts consisting of two components with almost no activity. This point is different from the case of Rh-ReO where Rh is a good component for the hydrogenolysis reaction. As a result, it is concluded that the synergy between Ir and ReO generates the catalysis of the glycerol hydrogenolysis to 1,3-PrD. 

Fig. 23 Comparison of transition state in the glycerol hydrogenolysis based on the proposed model structures of Rh-ReO, Rh-MoO and Ir-ReO,...

Nakagawa Y, Tomishige K (2011) Heterogeneous catalysis of the glycerol hydrogenolysis. Catal Sci Technol 1 179-190... 

Miyazawa T, Koso S, Kunimori K, Tomishige K (2007) Catalyst development of Ru/C for glycerol hydrogenolysis in the combination with the ion exchange resin. Appl Catal A 318 244-251... 

Shimao A, Koso S, UedaN, Shinmi Y, Furikado I, Tomishige K (2009) Promoting effect of Re addition to Rh/Si02 on glycerol hydrogenolysis. Chem Lett 38 540-541... 

Balar u, M., Rekha, V., Prasad, P.S., et al., 2009. Influence of solid acids as co-catalysts on glycerol hydrogenolysis to propylene glycol over Ru/C catalysts. Applied Catalysis A 354, 82-87. 

Chiu, C.W., Dasari, M.A., SutterlLn, W.R., et al., 2006. Removal of residual catalyst from simulated biodiesel s crude glycerol for glycerol hydrogenolysis to propylene glycol. Industrial Engineering Chemistry Research 45, 791-795. 

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