Method of purifying isosaccharinate

1. A method for preparing an acidic solution containing ISA (isosaccharinate), the method comprising the steps of:

a) preparing a solution of X 2 CO 3 and XOH;

b) adding Ca(ISA) 2 to the solution from step a) and agitating, thereby precipitating solid CaCO 3 and leaving dissolved X(ISA) in solution;

c) removing the solid CaCO 3 precipitate from the solution from step b), thereby leaving a solution containing dissolved X(ISA) and residual X 2 CO 3 and XOH; and

d) adjusting the pH of the solution from step c) to between approximately 4.5 to 5.0, thereby removing excess carbonate and hydroxide;

wherein X is selected from the group consisting of Na and K.

2. The method of claim 1 , wherein the step of adjusting the pH in step d) comprises adding HCl.

3. The method of claim 1 additionally comprising:

e) adding CaCl 2 to the solution from step d), thereby precipitating solid purified Ca(ISA) 2 .

4. The method of claim 3 additionally comprising:

f) removing and washing the precipitated purified Ca(ISA) 2 from the solution from step e).

5. The method of claim 4 additionally comprising steps for producing very high purity Ca(ISA) 2 by repetitively removing X 2 CO 3 and XOH impurities; wherein the additional steps comprise: repeating steps a) through f) one or more times; while reusing the precipitated purified Ca(ISA) 2 produced in step f) as the source of Ca(ISA) 2 material used in step b).

6. The method of claim 1 , additionally comprising adding the solution from step d) to a foam, gel, or strippable coating.

7. The method of claim 1 , wherein the acidic solution containing ISA additionally comprises one or more substances selected from the group consisting of: non-ISA organic chelators, inorganic chelators, carbonates, oxidizers, anti-freezes, and surfactants.

8. The method of claim 4 , further comprising, after step f), recovering the washed precipitated purified Ca(ISA) 2 by evaporation or freeze-drying.

9. A method for preparing highly purified Ca(ISA) 2 , the method comprising the steps of:

a) preparing a solution of X 2 CO 3 and XOH;

b) adding Ca(ISA) 2 to the solution from step a) and agitating, thereby precipitating solid CaCO 3 and leaving dissolved X(ISA) in solution;

c) removing the solid CaCO 3 precipitate from the solution from step b), thereby leaving a solution containing dissolved X(ISA) and residual X 2 CO 3 and XOH;

d) adjusting the pH of the solution from step c) to between approximately 4.5 to 5.0 by adding HCl, thereby removing excess carbonate and hydroxide;

e) adding CaCl 2 to the solution from step d), thereby precipitating solid purified Ca(ISA) 2 ;

f) removing and washing the precipitated purified Ca(ISA) 2 from the solution from step e); and

g) repeating steps a) through f) one or more times; while reusing the precipitated purified Ca(ISA) 2 produced in step f) as the source of Ca(ISA) 2 material used in step b);

wherein X is selected from the group consisting of Na and K.