Catalytic activity of nickel-copper alloys in the hydrogenation of acetone

Babková, Petra; Avetisev, A. K.; Lyubarskii, G. D.; Gel'bshtein, A.I.

doi:10.1007/bf00896227

Cited by 2 publications

(9 citation statements)

References 6 publications

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“…The lack of any mention of deactivation in these previous studies 10,17,19,25 is rather puzzling based upon the observations in this study. The idea was considered that perhaps the lower reaction temperatures employed in some of those studies (below 373 K) were in some way preventing or minimizing deactivation, thereby preventing its detection.…”

Section: Discussioncontrasting

confidence: 65%

“…For the Cu/Al 2 O 3 and Cu/Cr 2 O 3 catalysts, 10 the TOFs are about 3-fold higher than the initial TOFs measured on similar sized copper particles in this study. The TOF on the copper powder used by Babkova et al 25 is slightly lower than that for 20Cu, which was the catalyst with an average particle size closest to their catalyst, and it is twice as high as the TOF on the Cu powder studied here. This behavior is consistent with the trend exhibited in our study, in which the Cu powder with a much larger average particle size exhibited a noticeably lower TOF than that for 20Cu.…”

Section: Discussioncontrasting

confidence: 61%

“…Babkova and co-workers have reported the results of a comprehensive vapor-phase study of acetone hydrogenation below 373 K over bulk copper 17 as well as over a series of Ni-Cu alloys. 25 Again, the only observed product was 2-propanol, and they found that the acetone hydrogenation kinetics for both Ni and Ni-Cu alloys were quite similar to the kinetics observed on copper. More recently, Tripol'skii et al studied vapor-phase acetone hydrogenation over Cu/Al 2 O 3 and Cu/Cr 2 O 3 catalysts and also reported 2-propanol as the only detectable product.…”

Section: Discussionmentioning

confidence: 79%

“…Babkova and co-workers do not indicate any deactivation in their reports on acetone hydrogenation below 373 K over either copper 17 or Cu-Ni alloys. 25 Similarly, deactivation is not addressed by Tripol'skii et al in their study of acetone hydrogenation below 373 K over Cu/Al 2 O 3 and Cu/Cr 2 O 3 10 or by Valaraivan et al in their study of this reaction over Mg-Cu intermetallics. 19 However, Cunningham and co-workers do mention a continuous decline in the activity of copper powder for acetone hydrogenation at 423 ( 5 K and 0.05 atm acetone.…”

Section: Discussionmentioning

confidence: 98%

“…From the data available for rates of acetone hydrogenation over Cu powder 25 and over Cu/Al 2 O 3 and Cu/Cr 2 O 3 , 10 an effort was made to calculate TOFs and compare them with the values obtained in this study. This endeavor is difficult because there is no mention of whether the previously reported rates are initial or "steady-state" values; nevertheless, it is still useful to make such a comparison.…”

Section: Discussionmentioning

confidence: 99%

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Influence of Crystallite Size on Acetone Hydrogenation over Copper Catalysts

2004

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Acetone hydrogenation was studied over a family of Cu/SiO2 catalysts as well as UHP Cu powder and a Cu chromite catalyst. Oxygen chemisorption via dissociative N2O adsorption was used to count surface Cu atoms and calculate crystallite sizes, and a microwave absorption technique was used to measure the electrical conductivity of these Cu particles. Under differential reaction conditions at 423 K and 1 atm, all catalysts exhibited deactivation on stream and activities were typically 10-20% of their initial values after 3-4 h on stream. However, initial turnover frequencies (TOFs) varied from 0.056 s(-1) on the most highly dispersed Cu catalyst to 0.50 s(-1) on Cu powder, with the highest TOF of 2.4 s(-1) occurring on 110 nm crystallites. A similar trend with a broader (80-fold) variation was observed in the "steady-state" TOF values. Apparent activation energies varied between 11 and 14 kcal/mol. These initial TOF values are in good agreement with previous results, and a correlation exists between TOF and Cu crystallite size in this reaction, which appears to be structure sensitive. In addition, the electrical conductivity of these dispersed Cu nanoparticles, which was always less than that of bulk Cu, also increased with increasing Cu crystallite size; consequently, the change in this parameter may offer a possible explanation for the increase in TOF.

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Section: Discussioncontrasting

confidence: 65%

Section: Discussioncontrasting

confidence: 61%

Section: Discussionmentioning

confidence: 79%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

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