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The Journal of Physical Chemistry, Vol. 90, No. 17, 1986
Additions and Corrections
TABLE I: Rmults Obtained with Unpromoted and K+-PromotedV,O, Layers Supported on Alumina and Magnesia catalyst' A19OrV AI;O;-2V A1203-V-Kt A120,-2V-Kt MOO-V MgO-2V MgO-V-Kt MgO-2V-Kt
[Vst], mmol/(g cat.) 0.34 0.63 0.25 0.47 0.22 0.29 0.15 0.22
[K'], mmol/(g cat.)
4.8 3.6 0.44 0.72
Tm,bK
780 770 840 f 5 840 f 5 840 860 825 825
Agll/Ag, after TPR 1.1 1.1 1.7 1.5 1.3 1.2 1.4
selectivity to formaldehyde, % 7 1538 K) 3 (553 K j 41 (553 K) 81 (568 K) 87 (560 K) 81 (560 K)
T,,, represents the temperature of maximum hydrogen cona Monolayers and double-layer catalysts are denoted by -V and -2V, respectively. sumption in the TPR profiles. TPR profiles of promoted and unpromoted catalysts exhibited a similar shape.2
Our results extend the previously established correlation between the vanadyl bond strength and the partial oxidation selectivity. In a comparative study of Vz05 supported on various carriers we had found (i) that both AgulAg, and T,,, can be used as a measure for the V=O bond strength and (ii) that an increase of these quantities corresponded to an increase in the selectivity to formaldehyde. Here we have shown that this correlation is equally valid in the comparison of promoted and unpromoted V,05 systems.
(3) Shanna,V.K.;Wohun, A.; Baiker, A. J. Phys. Chem. 1986,90,2715. (4) Monti, D.; Baiker, A. J. Catal. 1985, 83, 323.
Acknowledgment. Financial support by the Swiss National Science Foundation is gratefully acknowledged. Department of Industrial and Engineering Chemistry Swiss Federal Institute of Technology ETH-Zentrum, CH-8092 Ziirich, Switzerland Institute of Physical Chemistry University of Bayreuth 0-8580 Bayreuth. FRG Received: February 5, I986
A. Baiker*+ M. GLinski* J. Kijenski' V. K. Sharmat A. Wokaud
Swiss Federal Institute of Technology. 'On leave from the Technical University of Warsaw, Poland. f University of Bayreuth.
ADDITIONS AND CORRECTIONS 1985, Volume 89
Jamey K. Hovey* and Peter R. Tremaine*: Thermodynamics of the Complexes of Aqueous Iron(III), Aluminum, and Several Divalent Cations with EDTA: Heat Capacities, Volumes, and Variations in Stability with Temperature. Pages 5541-5549. The ionic scale used in this work was C;"(H+,aq) = -63 J K-' mol-', not -68 J K-' mol-' as reported. Equations 20, 22, and 23 should read
GgUl = -16.2Q2 J K-'mol-'
G&nmul = cpo- 63Q + 16.2Q2 Moreover, some values of ~$m,,, are incorrectly plotted in Figure 4. The discussion was based on the correct equations and the conclusions are unchanged. The corrected Figure is shown elsewhere' with additional data. (1) Hovey, J. K.; Hepler, L. G.; Tremaine, P. R., submitted to Solution Chem.
J.
