AMINO ACID SURFACTANTS
The present disclosure provides derivatives of amino acids that have surface-active properties. The amino acid can be naturally-occurring or synthetic, or they may be obtained via a ring-opening reaction of a lactam, such as caprolactam. The amino acid may be functionalized to form a compound that is surface-active and have advantageous surfactant characteristics. The compounds of the present disclosure have low critical micelle concentrations (CMC) as well as superior ability to lower the surface tension of a liquid.
1 . A compound of the following formula:
wherein X is an anion selected from the group consisting of chloride, bromide, iodide, and hydroxide.
2 . The compound of claim 1 , wherein the compound is 6-(dodecyloxy)-N,N,N-trimethyl-6-oxohexan-1-aminium iodide, having the following formula:
3 . The compound of claim 1 , having a critical micelle concentration (CMC) of about 1 mmol in water.
4 . The compound of claim 1 , having a plateau value of a minimum surface tension of about 33 mN/m.
5 . The compound of claim 1 , having a surface tension in water equal to or less than 33.8 mN/m at a concentration of 1.0 mmol or greater.
6 . The compound of claim 1 , having a surface tension in water equal to or less than 39.9 mN/m at a surface age of 75 ms or greater.
7 . A method of synthesizing an amino acid surfactant, comprising the steps of:
(1) opening a lactam to yield an amino acid having an N-terminus;
(2) reacting the N-terminus of the amino acid with an alkylating agent to yield a tertiary amine;
(3) reacting the tertiary amine with an alcohol under acidic conditions to yield an amino acid ester having an N-terminus; and
(4) reacting the N-terminus of the amino acid ester with an alkylating agent under basic conditions to yield an amino acid surfactant of the following formula:
wherein X is an anion selected from the group consisting of chloride, bromide, iodide, and hydroxide.
8 . The method of claim 7 , wherein in step 1, the lactam is caprolactam.
9 . The method of claim 7 , wherein in step 2, the alkylating agent is formaldehyde or paraformaldehyde.
10 . The method of claim 7 , wherein in step 3, the alcohol is dodecanol.
11 . The method of claim 7 , wherein in step 3, the acid is p-toluene sulfonic acid.
12 . The method of claim 7 , wherein in step 4, the alkylating agent is methyl iodide.
13 . The method of claim 7 , wherein in step 4, the base is sodium carbonate.
14 . A liquid composition comprising:
a medium; and
a surfactant of the following formula:
wherein X is an anion selected from the group consisting of chloride, bromide, iodide, and hydroxide.
15 . The composition of claim 14 , wherein the medium is water.