Process to produce fluorinated betaines
View Patent ↗A process to prepare fluorinated sulfobetaine compounds of formula (I) wherein R f is C 2 to C 10 fluoroalkyl optionally interrupted by one or more of O, CH 2 , CHF, or combinations thereof; R 1 is C 1 to C 10 alkylene; R 2 is C 1 to C 6 alkylene or a chemical bond; R 3 is H or CH 3 ; R 4 is C 1 to C 6 alkylene containing at least one hydroxyl group; R 5 is H or CH 3 ; and R 6 is H or CH 3 ; comprising contacting a fluorinated sulfonamide amine of formula (II) with an aliphatic chlorosulfonic acid or salt thereof of formula (III) in the presence of water and at least one alkylene glycol, and optionally at least one alkyl carbonate, said fluorinated sulfobetaine having reduced free chloride content and reduced flammability without the need for additional purification steps.
1. A process to prepare fluorinated sulfobetaine compounds of formula (I)
wherein
R f is C 2 to C 10 fluoroalkyl optionally interrupted by one or more of O, CH 2 , CHF, or combinations thereof;
R 1 is C 1 to C 10 alkylene or a chemical bond;
R 2 is C 1 to C 6 alkylene;
R 3 is H or CH 3 ;
R 4 is C 1 to C 6 alkylene containing at least one hydroxyl group;
R 5 is H or CH 3 ; and
R 6 is H or CH 3 ;
comprising contacting a fluorinated sulfonamide amine of formula (II)
wherein R f , R 1 , R 2 , R 3 , R 5 and R 6 are each defined as in Formula (I);
with an aliphatic chlorosulfonic acid or salt thereof of formula (III)
wherein R 4 is C 1 to C 6 alkylene containing at least one hydroxyl group; X is chlorine; and M is Na, K, Li, or Ca;
in the presence of water and at least one alkylene glycol, and optionally at least one alkyl carbonate, wherein the ratio of water to the total amount of alkylene glycol and optional alkyl carbonate is from about 1:19 to about 1:3.
2. The process of claim 1 wherein the contacting is conducted in the presence of water, alkylene glycol, alkyl carbonate, and optionally an alcohol of low flammability.
3. A process of claim 1 wherein the contacting occurs at a temperature from about 80° C. to about 120° C.
4. A process of claim 1 wherein the contacting occurs in the presence of water and at least two alkylene glycols.
5. A process of claim 4 wherein the two alkylene glycols are hexylene glycol and 1,2-propylene glycol.
6. A process of claim 1 wherein R f is C 4 to C 6 fluoroalkyl and R 1 is C 2 alkylene.
7. A process of claim 1 wherein the ratio of water to the total amount of alkylene glycol and optional alkyl carbonate is from about 1:10 to about 1:4.
8. A process of claim 1 wherein a solution of the compound of formula (I) is filtered to remove metal chlorides, and after such filtering has a free chloride content of less than 3% by weight of compound of formula (I).
9. A process of claim 8 wherein one or more additional organic solvents chosen from glycols, alkyl carbonates or alcohols are added to the solution of compound of formula (I) prior to filtering.
10. A process of claim 8 wherein the solution of compound of formula (I) is heated to partially distill out water prior to filtering.
11. A process of claim 8 wherein the solution of compound of formula (I), after filtering, is diluted with water and optionally other organic co-solvents to yield a stable solution.
12. A process of claim 9 wherein the solution of compound of formula (I), after filtering, is diluted with water and optionally other organic co-solvents to yield a stable solution.
13. A process of claim 10 wherein the solution of compound of formula (I), after filtering, is diluted with water and optionally other organic co-solvents to yield a stable solution.