Hydrogenolysis of Glycerol to 1,2-Propanediol over Nano-Fibrous Ag-OMS-2 Catalysts

Abstract

Increasing demand for biodiesel production would lead to tremendous supply of glycerol as a coproduct, which is almost 10% by weight. Therefore, utilization of bioglycerol into valuable chemicals is timely to reduce the cost of biodiesel. Both 1,2and 1,3-propanediols are very useful chemicals which can be produced from glycerol. This paper describes a novel process for selective hydrogenolysis of glycerol to 1,2-propanediol over silver incorporated octahedral molecular sieve (OMS-2) catalyst. Also, the current work describes the use of silver as the catalyst for the first time for hydrogenolysis of glycerol. Both batch and continuous mode of operations have been studied to determine the stability of the catalyst. Different loadings (10À30% w/w) of Ag were incorporated in OMS-2 by the precipitation method and used in the reaction. Thirty % w/w Ag-OMS-2 was the best catalyst. It was characterized by various techniques such as SEM, TGA, XRD, N 2 adsorptionÀdesorption, EDAX, TPD-TPR, and FTIR. It is a nano fibrous crystalline material. This Article reports a comprehensive account of this catalytic process.The initial studies were carried out in a batch reactor to optimize the reaction parameters. High conversion of glycerol (about 65À70%) with about 90% selectivity toward 1,2-propanediol was obtained within 8 h under hydrogen pressure. The time-on-stream (TOS) analysis studies were conducted in a fixed bed reactor up to 150 h, which demonstrated that the catalyst was stable and the process has a potential for commercial exploitation. methane sulfonic acid in a water-sulfolane mixture resulted in to 1-propanol, 1,2-PDO, and 1,3-PDO in a 47:22:31 ratio. 12 Dehydroxylation of glycerol in sulfolane catalyzed by a homogeneous complex of ruthenium as catalyst at 52 atm and 110 °C resulting in to very low yields 1,2-/1,3-PDO is reported. 13 The hydrogenolysis of glycerol with copperÀchromiumbased catalysts yielded only 1,2-PDO. 14 Hydrogenolysis of glycerol under 30 MPa H 2 at 260 °C over Raney Ni, Ru, Rh, and Ir catalysts yielded mainly methane, but in the presence of Raney Cu, 1,2-PDO was the main product. 15 Furthermore, other catalysts such as Cu/C, 16 CuÀPt, and CuÀRu bimetallic catalysts 17 have been reported at 1.0À4.0 MPa and 493À513 K. Hydrogenolysis of glycerol and other polyols over Ni/Re catalyst under 8.2 MPa H 2 and 230 °C in 4 h led to 44% 1,2-PDO, 5% 1,3-PDO and 13% ethylene glycol. 18 Glycerol hydrogenolysis on several heterogeneous catalysts under 8 MPa H 2 pressure at 180 °C was investigated over various metals (Cu, Pd, Ni and Rh), supports (ZnO, C and Al 2 O 3 ), solvents (H 2 O, sulfolane and dioxane), and additives (H 2 WO 4 ) were tested to improve the reaction rate and selectivity. 19 Glycerol hydrogenolysis to ethylene glycol and 1,2-PDO was reported with Rh/SiO 2 catalysts including the effect of sulfur and temperature. 20À22 Hydrogenolysis of glycerol over carbon-supported Ru, Pt, and bimetallic PtÀRu and AuÀRu catalysts is also reported. 23,24 The effects of NaOH and CaO addition on the reaction...

Liquid phase conversion of Glycerol to Propanediol over highly active Copper/Magnesia catalysts

“…Arrhenius plot was made by plotting ln (k/ L mol −1 h −1 ) vs. (1/T) (figure 10b). The calculated activation energy of glycerol hydrogenolysis over Cu/MgO catalyst in temperature range of 190-225 • C is found to be 28.7 ± 0.8 kcal/mol, a value in agreement with that reported by Sharma et al 19 (31.5 kcal/mol) and Yadav et al 33 (27.5 kcal/mol). This activation energy value also indicates that the hydrogenolysis reaction is intrinsically kinetically controlled.…”

“…This activation energy value also indicates that the hydrogenolysis reaction is intrinsically kinetically controlled. 33 From the current study it is observed that the MgO supported Cu catalysts increase the activity for hydrogenolysis of glycerol to produce 1,2-PDO in good yield. The increase in activity is due to the combined effects of metal dispersion over support and acidic strength which is confirmed by characterization results.…”

Development of cerium promoted copper–magnesium catalysts for biomass valorization: Selective hydrogenolysis of bioglycerol

“…Among various utilization routes of glycerol, the selective hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO) is of paramount research interest to the scientific community. The 1,2-PDO is a vital desirable chemical that can be used in a wide variety of industrial applications, such as pharmaceuticals, antifreeze additives, cosmetics, polymers, tobacco industries, etc [17][18][19]. 1,2-PDO is usually produced by a petrochemical approach through the hydration of hazardous propylene oxide, which is an expensive and environmentally unfriendly method [7].…”

Efficient production of propylene in the catalytic conversion of glycerol

“…Hydrogenolysis of glycerol into 1,2-PDO, which is a valuable chemical mainly used for producing polymers, has been intensively reported over various metal catalysts such as Cu [18][19][20][21][22][23][24][25][26], Rh [27,28], Ru [29,30], Ni [31,32], Pt [33,34], and Ag [26,35]. In this reaction, HA is primarily generated in the dehydration of glycerol, and then hydrogenated into 1,2-PDO [15,16].…”