Sibunit

The sitosterol hydrogenation and deactivation kinetics was determined in a shaking constant-pressure batch reactor by using the new type of synthetic support material (mesoporous carbon Sibunit) for palladium (4wt% Pd) [55]. 

Figure 8.11 Example of data fitting results - concentrations of sitosterol, campesterol, and the products in the hydrogenation of sitosterol to sitostanol (increasing curve) on Pd/Sibunit. The lower curves represent campesterol and campestanol.

Figure 15.1 High resolution transmission electron microscopy images (HR-TEM) of 5 wt% Pd (a) and 50 wt% Pt-Ru (b) particles supported on carbon supports of the Sibunit family with surface areas of about 6m g (a) and 72m g (b). (c) Fourier-transformed image of (b). ((a) Reprinted from Pronkin et al. [2007], Copyright 2007, with permission from Elsevier, (b) and (c) reprinted from Gavrilov et al. [2007]—Reproduced by permission of the PCCP Owner Societies.)...

Rao V, Simonov PA, Savinova ER, Plaksin GV, Cherepanova S V, Kryukova GN, Stimming U. 2005. The influence of carbon support porosity on the activity of PtRu/Sibunit anode catalysts for methanol oxidation. J Power Sources 145 178-187. 

Sibunit Supported Catalysts for Hydrogenolysis of a C-O Bond in Bio-Crude-OiF Components... 

ABSTRACT New catalysts for hydrogenolysis of C-O bond are proposed. The catalysts were prepared by anchoring of Mo, (Ni,Mo) and (Co,Mo) complexes to the surface of a new carbon support Sibunit. Two types of the active component were prepared - oxide and sulfide forms. The catalysts were tested in a model reaction of tetrahydroftiran hydrogenolysis. As shown, the catalysts are active in the purposeful reaction of C-O- bond hydrogenolysis and do not catalyze the side reactions -polymerization and dehydration of tetrahydrofuran. 

In our work, Sibunit, an artificial carbon material, was used as a support. The methods of Sibunit synthesis permit one to vary surface and size of the support pores within a wide range. Because of high thermal stability, mechanical strength, and... 

In contrast to alumina, Sibunit is not active on hydrogenolysis of THF (Table 1). The products of polymerization were not observed even at high temperature (Table 2). The monometallic molybdenum catalysts exhibit low activity. The oxide catalysts are more active than sulfides by a ftictor of 3. At high temperature, their activity is comparable (Table 1). 

Sibunit is the most suitable support for the catalysts of hydrogenolysis of the C-0 bond in THF as a model of the bio-cmde-oilcomponent ... 

SI = Sibunit (activated pyrolytic carbon), A = Anthralur (active carbon). Subscript ox means oxidized support (with the oxidant indicated in the brackets) HT the support calcined in inert atmosphere at 1000 °C. Determined from Na2C03, NaOH, NaOEt, and HCl consumption in accordance with Boehm s method. Source Ref. 16. 

Table 2 Concentration of re-Sites of A2 Type on the Surface of Sibunit (SI)... 

Figure 1 Relationship between the average size (dn,dy) of Pd particles in Pd/C catalysts and the equilibrium constant (K2) of formation of the metal precursors (surface 71-complexes of PdCb with the A2 sites). (From Ref. 16.) Pd/C catalysts are prepared by reduction of PdCb/C in flowing H2 at 250 °C for 3 h the metal loading is 1 pmol/m ( S phenoi)- Supports. Active carbons Eponit 113H (1), PN (2), AR-D (3). Activated pyrocarbon Sibunit (4,6,7). Carbon blacks PME-800 (5), PM-105 (8).

Figure 1 Adsorption density vs. pH curves of carbon supports in 0.1 M KNO3 solution. , Ketjenblack EC A, Sibunit , CCl.

Hillerova et al. [71] compared the performance, in parallel HDN of pyridine and HDS of thiophene, of sulfided Ni-Mo catalysts supported on alumina and on a special carbon named Sibunit, which is based on graphitized carbon black and is mainly mesoporous [79]. The carbon-supported catalysts showed a higher resistance to inhibition by pyridine, higher HDN activity, and a higher HDS/HDN activity ratio than that of the commercial alumina-supported catalyst. 

In addition to its use as a catalyst support (see Chapter 4), carbon can find applications as a catalyst on its own. Activated carbon catalysts have long been used in the production of phosgene [1,2] and sulfur hahdes [3], The corresponding technologies seem to be well established, although the mechanistic details are not known in detail [4], The only recent pubhcation on this subject concerns the reduction of the by-product carbon tetrachloride using Sibunit (a carbon material developed at the Boreskov Institute of Catalysis) instead of the coconut shell-based activated carbon catalyst [5],... 

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