Standard enthelpy of formation needed for EDTA metal complexes

[Gollegun]

Hi,

I am trying to solve the chemical equilibria in a kraft mill bleach plant to predict mineral scale deposits. I am using the van't Hoff equation to account for temperature dependence of the formation constants, but I need the enthalpy of reaction for all equilibria and I am missing some data.

What I am missing is data for EDTA complexes with Na+ and K+. I have the std enthalpy of formation for EDTA, Na+ and K+ but in order to get the enthalpy of reaction I also need EDTA-Na and EDTA-K.

Does anyone know where I can find these values?

Kind regards

Gollegun

 

[Borek]

Formation constants for EDTANa and EDTAK are quite small from what I remember - are you sure they play any important role in the system?

 

[Gollegun]

Formation constants for EDTANa and EDTAK are quite small from what I remember - are you sure they play any important role in the system?

I just automatically included all the ions of significant concentration. But you are right, the formation constants of Na and K are very low in comparison to other metals such as Ca and Mg - and they can probably be neglected. I'll try this and see how it works out.

Thanks!