Supplementary Material

A kinetic study of D-glucose oxidation by bromine in aqueous solutions

Branimir N. Grgur1,*, Dragana L. Žugić1, Milica M. Gvozdenović1, Tomislav Lj. Trišović2

1Faculty of Technology and Metallurgy,

University of Belgrade, Karnegijeva 4,

2Institute of Technical Science, Serbian Academy of Science and Arts,

Knez Mihailova 35

11020 Belgrade,

Serbia and Montenegro

*corresponding author: e-mail:


The distribution of bromine species (free bromine, tribromide ions, hypobromous acid and hypobromite) in a solution containing bromide as a function of pH can be calculated starting from the chemical equilibria equations:

Br2 + 2H2O HOBr + H3O+ + Br- (5)

Kq1 = K1 = = 7.2 x 10-9 (5a)

HOBr + H2O BrO- + H3O+ (6)

Kq2 = K2 = = 2 x 10-9 (6a)

Br2 + 2OH- BrO- + Br- + H2O (7)

Kq3 = K3 = = 2x108 (7a)

Br2 + Br- Br3- (8)

Kq4 = = 16.85 M-1 (8a)

Assuming that concentration corresponds to activity and that water has unity activity, the following procedure was used to determine the distribution of bromine species as a function of pH. The mass-balance equation with respect to free bromine, c(Br)s, in the solution is given by:

c(Br2)s = c(Br2)T – c(Br3-) – c(HOBr) – c(BrO-) – c(BrO-)HOBr (9)

where c(Br2)T is the total analytical concentration of bromine in the solution.

The concentration of hypobromite ions, c(BrO-)HOBr, produced by hydrolysis of hypobromous acid, Eq. 6, is given by:

c(BrO-)HOBr= (10)

Dividing Eq. 9 by c(Br)s, the following is obtained:

(11)

this on rearrangement gives:

(11a)

In order to solve Eq. 11a, it is necessary to rearrange Eqs. 5a–8a in the following manner:

= (5b)

c(BrO-)= (6b)

= (7b)

=Kq4 c(Br) (8b)

Introducing Eqs. 7b, 8b. and 10 into Eq. 11a, the following equation is obtained

c(Br2)s (11b)

Finally, after the introduction of the dependence c(HOBr)/c(Br2)s, given by Eq. 5b, the pH dependence of the free bromine concentration in the solution is obtained:

c(Br2)s (12)

Once the pH dependence of the free bromine concentration is known, it is also possible to calculate, by a similar procedure, the pH dependence of the concentrations of all the other species in the solution. Thus, for hypobromous acid, after the introduction of Eqs. 6b, 7b and 8b into Eq. 11:

(11c)

the pH dependence of the hypobromous acid concentration in the solution can be obtained by rearrangement:

c(HOBr)= – c(Br2)s (13)

For the determination of the total concentration of hypobromite ions, Eq. 11 must be modified in the following manner:

(11d)

After the introduction of Eqs. 5b and 8b into Eq. 11d and rearranging, the total concentration of hypobromite ions as a function of pH is given by:

c(BrO-) = – c(Br2)s (14)

Applying a similar procedure, the pH dependence of the concentration of tribromide ions in the solution as a function of pH can be obtained from a modified form of Eq. 11:

(11e)

After introducing Eq. 5b - 8b and rearranging, the following equation is obtained:

c(Br3-)= – c(Br2)s (15)

From Eqs. 12–15, it is possible, using a simple mathematical program, to obtain the distribution of bromine species in a solution containing bromide as a function of pH.

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