Preparation of a foam stabilizing composition including a siloxane cationic surfactant and a metal salt

A foam stabilizing composition comprising:

• (a) a salt comprising a metal and an ion selected from the group consisting of a chloride ion and a sulfate ion, where the salt is selected from the group consisting of
• (a1) the metal is in Group 13, the ion is the chloride ion, and the salt is present in an amount sufficient to provide the chloride ion in a concentration >10 mM to <300 mM;
• (a2) the metal is in Group 2, the ion is the chloride ion, and the salt is present in an amount sufficient to provide the chloride ion in a concentration >10 mM;
• (a3) the metal is in Group 1, the ion is the chloride ion, and the salt is present in an amount sufficient to provide the chloride ion in a concentration >300 mM;
• and
• (a4) the metal is in Group 1, Group 2 or Group 13, the ion is the sulfate ion, and the salt is present in an amount sufficient to provide the sulfate ion in a concentration of ≥10 mM;
• (b) a siloxane cationic surfactant having general formula (I):
• [Z1-D1-N(Y)a(R)2−a]+y[X−x]n (I),
• where Z1 is a siloxane moiety;
• D1 is a divalent linking group;
• R is H or an unsubstituted hydrocarbyl group having from 1 to 4 carbon atoms;
• each Y has formula -D-NR13+, where D is a divalent linking group and each R1 is independently an unsubstituted hydrocarbyl group having from 1 to 4 carbon atoms;
• subscript a is 1 or 2;
• 1≤y≤3;
• X is an anion;
• subscript n is 1, 2, or 3;
• and 1≤x≤3, with the proviso that (x*n)=y;
• (c) an organic cationic surfactant having general formula (II):
• [Z2-D2-N(Y)b(R)2−b]+y[X−x]n (II),
• where Z2 is an unsubstituted hydrocarbyl group;
• D2 is a covalent bond or a divalent linking group;
• subscript b is 1 or 2;
• and each R, Y, superscript y, X, subscript n, and superscript x is independently selected and as defined above;
• and
• (d) water.