Phase hydrogenolysis

The gas-phase hydrogenolysis of methyl formate over a copper chromite catalyst (ref. 33) at atmospheric pressure revealed that the decarbonylation of methyl formate according to ... 

The results of the experiments conducted in the presence of CO for both vapour-phase and liquid-phase reactions have important implications for the methyl formate route to methanol. The liquid-phase hydrogenolysis study (ref. 37) and the earlier carbonylation work (ref. 32) suggest that it is not feasible to conduct methanol synthesis via methyl formate in a single reactor. Both reactions require high pressures in order to obtain useful rates of reaction at moderate temperatures and the high CO pressures would severely limit the hydrogenolysis reaction. 

Oxiranes can be hydrogenolyzed easily alcohols and oxo compounds are formed as the result of primary processes [11,20,21]. The less sterically hindered bond is cleaved on Pt and Pd whereas the more hindered bond is broken on Ni and Cu. The rates of transformation of dimethyloxirane stereoisomers were also different on these metals, c/5-2,3-Dimethyloxirane is transformed much more rapidly than the trans isomer on Pt and Pd catalysts, whereas on Ni the two isomers are converted at almost the same rate [22]. Solid-phase hydrogenolysis of oxiranes on supported palladium catalysts has also been reported [23]. 

D.M. Monti, M.S. Wainwright, D.L. Trimm and N.W. Cant, Kinetics of vapor-phase hydrogenolysis of methyl formate over copper on silica catal) ts, Ind. Eng. Chem. Prod. Res. Dev., 24 397-401, 1985. 

Liquid phase hydrogenolysis of butyl acetate was carried out in a stirred (rate = 600 rpm) stainless steel autoclave. Details on the catalysts, treatments and reaction conditions are given in the corresponding Tables. The conversion, selectivity and yield as well as first order rate constant obtained in the hydrogenolysis of butylacetate on Pt, RePt and RuRePt catalysts are summarized in Table 23.220... 

Characterization and Catalytic Activity. 2.2.2.2.1 Hydrogenolysis of Ethyl Dodecanoate on CuO-ZnO-A Os Catalysts. - The authors of this review have also investigated the liquid phase hydrogenolysis of ethyl dodecanoate over three commercial CuO-ZnO-AbOa (CZA-1, CZA-2 and CZA-3) and a laboratory made CuO-ZnO-AbOa catalyst (CZA-4) in a stirred tank reactor at 90 bar hydrogen pressure and 250 X-ray diffraction (XRD) was used to characterize both the oxide and form of the catalysts, as well as the reduced and then used catalysts (see previous paragraph. Table 26 and Table 27). ... 

Alumina supported Sn-Ru and Re-Pt catalysts were found to be highly active and selective in liquid phase hydrogenolysis of ethyl dodecanoate and butyl acetate to the corresponding alcohol. The content of ionic forms of the second metals strongly affected the performance of these catalysts. The interaction between two metals in these catalysts has been shown by different experimental methods. 

K-size aggregate biofilm bacterial cell solid deposit fine particle gas phase hydrogenolysis hydrogenation inert gas reactor inlet liquid phase catalyst particle reforming solid phase reactor wall... 

The gas-phase hydrogenolysis of thiophene (C4H4S) to normal butane (n-CUHio) and hydrogen sulfide (H2S) takes place at 250 °C and 1 atm total pressure over a cobalt molybdate catalyst... 

Huang, L., Zhu, Y, Zheng, H., et al., 2008a. Vapor-phase hydrogenolysis of biomass-derived lactate to 1,2-propane-diol over supported metal catalysts. Applied Catalysis A 349, 204-211. 

Catalytic hydrogenation of furan to tetrahydrofuran is accompHshed in either Hquid or vapor phase. Hydrogenation of the double bonds is essentially quantitative over nickel catalysts but is generally accompanied by hydrogenolysis over the noble metals. 

One process (182) esterifi.es the acetic acid with ethanol (or methanol) and then converts the ester to alcohol by hydrogenolysis in the vapor phase over a copper—2inc catalyst. 

Many other authors studied the catalytic activity of palladium in more complicated hydrogenation reactions because of being coupled with isomerization, hydrogenolysis, and dehydrogenation. In some cases the temperatures at which such reactions were investigated exceeded the critical temperature for coexistence of the (a + /3)-phases in the other case the hydrogen pressure was too low. Thus no hydride formation was possible and consequently no loss of catalytic activity due to this effect was observed. 

Hydrogenolysis with a Pt catalyst in the gas phase has been reported to reduce nitro compounds, as well as primary and secondary amines. ... 

This interpretation of the experimental data is supported by the differences observed in the deactivation patterns and carbon contents after test, since one notorious effect of Hjp is the capacity to diminish the deactivation caused by coke deposition on the active sites [21,22]. This is supposed to be due to a reaction with the coke precursors, very likely a hydrogenolysis. In pure silica-aluminas, where no source of spillover is present, no special protection against deactivation should be observed. Indeed, the silica-aluminas lose most of their activity (about 80%) before reaching the steady-state and present the highest carbon contents after catalytic test. On the other hand, in the case of the mechanical mixtures, where spillover hydrogen is continuously produced by the CoMo/Si02 phase and can migrate to the silica-alumina surface, the predicted protection effect is noticed. The relative losses of activity are much lower... 

The quantity of AsPha fixed and Ce evolved after 3 h of reaction at 303,373, and 443 K, related to the amount of total Ni (As xed/Nit) or to the number of surface atoms (Asfixed/Nis) as reported in Table 6 indicates that the reaction of AsPha with Ni under H2 proceeds through a stepwise process, with a progressive hydrogenolysis of the As - Ph bonds. Moreover, after reaction at 443 K, the diffraction pattern of the sohd presents clear lines at 33.6 and 50.5 26 assigned to the NiAs phase (nickeUne), thus showing that an alloy has been formed. 

Other types of non-micro-channel, non-micro-flow micro reactors were used for catalyst development and testing [51, 52]. A computer-based micro-reactor system was described for investigating heterogeneously catalyzed gas-phase reactions [52]. The micro reactor is a Pyrex glass tube of 8 mm inner diameter and can be operated up to 500 °C and 1 bar. The reactor inner volume is 5-10 ml, the loop cycle is 0.9 ml, and the pump volume adds a further 9 ml. The reactor was used for isomerization of neopentane and n-pentane and the hydrogenolysis of isobutane, n-butane, propane, ethane, and methane at Pt with a catalyst. 

Elongation of the peptide chain in the direction of the N-terminal by a solid-phase procedure was introduced by Lavielle and coworkers,132 who prepared the glycopeptide [3-0-(2-acetamido-2-deoxy-/ -D-gluco-pyranosyl)-L-serine]-L-glycyl-L-alanine (189) by first coupling 168, de-protected by hydrogenolysis, to an L-alanyl resin (188), and, after re-... 

Hydrogenolysis of an aldehyde or ketone carbonyl to >CH2 is an important organic transformation, and classical procedures such as the Clemmenson and Wolff-Kishner reactions have limitations (24, 25) heterogeneous catalytic systems and several two-step procedures are also known (1, 24, 26). Our observation of this conversion in what is essentially a 2-phase medium... 

Table XV summarizes kinetic parameters for hydrogenolysis reactions of alkanes and cycloalkanes over film catalysts and over supported catalysts for which it can be reasonably assumed that reaction is confined to the metallic phase. These kinetic parameters refer to the overall reaction, i.e., to the rate of disappearance of the parent molecule. It will be evident from Table XV that the catalytic activity of a given metal with a given...

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