Technology development for iron Fischer-Tropsch catalysts. Final technical report, December 18, 1990--December 17, 1993 Page: 59 of 1,082

                                
[In the following the nomenclature is that used by Baes and Mesmer (II.24). In this
notation, Q is used to represent the formation quotient and K is the formation constant
that includes ionic activity coefficients. Thus, the formation quotient can be written:
[MX(OH), (=-y)+] [H+]y           [1.47]
[MZ+]x
where z is the charge on an ion, x represents the number of cations in a hydrolysis
product, y denotes the apparent number of OR ions in a hydrolysis product, Mz+ is
the concentration of of the metal cation. The corresponding formation constant is
then
K, = Q,[yg 1 gyH+  M~ (g=  H20 )        [.8]
where gy. is the ionic coefficient of MZ+, etc. and aH20 is the activity of water.]
In general, the formation reaction for a soluble hydrolysis product might be
written
xM(OH2) Z+ + yOH~ + aA- MOu(OH)y_(OH2)wA. (n-y-a)+ + (xw* + u -w)H20  [11.49]
where the oxygen ligands are 02-, OH, H20 and another anion A-. A limitation in
distinguishing by experiment between 02- and two OH- ligands and the ability to
detect water ligands causes the reaction to usually be written to include only
hydroxide as ligand:
xMZ+ + yOH - *t MX(OR), (x-y)+         [II.50]
A determination of the identity and stability of dissolved hydrolysis products has
proven to be difficult, primarily because:

II.31