Tertiary Amine-Based Switchable Cationic Surfactants and Methods and Systems of Use Thereof

A method for reversibly converting a tertiary amine compound of Formula I to a surfactant,

• R1R2NR3
• where
• at least one of R1, R2, and R3 hydrophobic moiety is selected from the group consisting of higher aliphatic moiety, higher siloxyl moiety, higher aliphatic/siloxyl moiety, aliphatic/aryl moiety, siloxyl/aryl moiety, and aliphatic/siloxyl/aryl moiety;
• and
• the rest of R1, R2, and R3 are selected from the group consisting of a substituted or unsubstituted C1 to C4 alkyl group, (SiO)1 to (SiO)2, and Cn(SiO)m where n is a number from 0 to 4 and m is a number from 0 to 2 and n+m≦4;
• where the higher aliphatic and/or siloxyl moiety is a hydrocarbon and/or siloxyl moiety having a chain length of linked atoms corresponding to that of C8 to C25, which may be substituted or unsubstituted, and may optionally contain one or more SiO unit, one or more aryl or heteroaryl groups, one or more ether linkages, one or more ester linkages or combinations of two or more of these, and wherein the hydrophobic moiety is not substituted with an aromatic group or an electronegative atom on the carbon alpha to the amine nitrogen or a fluorine atom on the carbon beta to the amine nitrogen and wherein an aryl or heteroaryl group is not directly attached to the amine nitrogen,
• said method comprising the step treating the tertiary amine compound with an ionizing trigger gas that comprises CO2, CS2, COS, or a mixture thereof, at a pressure and an amount sufficient to convert all or a substantial portion of the amine to said salt, wherein the total pressure of the ionizing trigger gas is approximately ambient pressure.

A switchable surfactant system comprising

• (a) water or an aqueous solution;
• (b) a switchable surfactant compound that is
• in its surfactant form, wherein the surfactant form is a tertiary amine salt comprising a hydrophobic portion, wherein said tertiary amine salt reversibly converts to a non-salt form following contact with vacuum, heat and/or flushing gas, wherein said flushing gas is a nonreactive gas that contains insufficient CO2, CS2, or COS to sustain the switchable surfactant compound in its salt form;
• in its non-surfactant form, wherein the non-surfactant form is a tertiary amine comprising a hydrophobic portion, wherein said tertiary amine reversibly converts to a salt form following contact with an ionizing trigger gas that comprises CO2, CS2, COS, or a mixture thereof, at a pressure and an amount sufficient to convert all or a substantial portion of the amine to said salt, wherein the total pressure of the ionizing trigger gas is approximately ambient pressure;
• or
• in a mixture of its surfactant form and its non-surfactant form;
• and
• (c) means for introducing
• (i) the vacuum, heat and/or a flushing gas;
• (ii) the ionizing trigger gas;
• or
• (iii) CO both (i) and (ii),