Synthesis of N‐acyl amino acids and correlation of structure with surfactant properties of their sodium salts

Abstract

The effect of structural variation in fatty acid and amino acid moieties on surfactant properties of sodium salts of N-acyl condensates of amino acids was investigated. Pure N-acyl leucines and N-lauroyl condensates of different amino acids were synthesized and neutralized. Among the N-acyl leucinates, Nlauroyl leucinate exhibited optimum properties and compared well with sodium lauryl sulfate (SLS). Among the salts of N~-lauroyl amino acids, N~-lauroyl lysinate was found comparable to SLS. Salts of Nalauroyl condensates ofleucine, tryptophan, phenylalanine and proIine showed good wetting ability; proline also displayed high calcium ion tolerance. Salts of Nlauroyl tyrosine and phenylalanine exhibited good foaming ability. N-Lauroyl aspartate showed inferior properties compared to SLS in spite of having an additional carboxylic group.KEY WORDS: N-acyl leucines, N-lauroyl amino acids, structure vs surfactant properties.

A Novel Synthesis of N-Alkoxycarbonyl Amino Acids and Surfactant Properties of Their Sodium Salts

“…Generally, they have been prepared from fatty acid chlorides and amino acids [10][11][12][13][14][15] , where acid halides are used to introduce the hydrophobic groups. However, on the view point of availability of starting materials, it may not be easy to obtain optically active fatty acids compared to the availability of optically active alcohols.…”

“…Among them, sodium salts of Nacyl amino acids are anionic surfactants with good biodegradability [1][2][3] , skin compatibility and antibacterial activity [4][5][6][7][8][9] and have been widely used in detergent, shampoo, cosmetic and food formulations. They are usually prepared from fatty acid chlorides and either pure amino acids or protein hydrolysates [10][11][12][13][14][15] . However, as the acid halides are used to introduce the hydrophobic groups, it may not be easy to vary the hydrophobic groups on the view point of availability.…”

Synthesis, Surface Active Properties and Cytotoxicity of Sodium <i>N</i>-Acyl Prolines

“…The emulsion stability of proline-based surfactants is as follows: SNAPro KNAPro PNAPro HNAPro CNAPro. The emulsion stability of mixture of sodium N-acyl prolines was superior as compared to pure individual fatty acyl prolines 30-213 s 2,19 . The emulsion stability decreased with an increase in the polarity of the amino acid head group from isoleucine to proline due to lower hydrophobicity 24 .…”

“…N-Palmitoyl proline showed the higher antimicrobial activity and good wetting ability among the other sodium N-palmitoyl amino acids 18,19 . Especially N-lauroyl proline exhibited the higher calcium tolerance compared to other N-lauroyl amino acids 2 . Very few reports are available on the synthesis of amino acid-based surfactants using mixture of fatty acids along with single chain fatty alkyl groups with better surface-active properties 20 23 .…”

Synthesis of Novel Lipoamino Acid Conjugates of Sapienic Acid and Evaluation of Their Cytotoxicity Activities

“…N-Sapienoyl amino acids were prepared by the SchottenBaumann reaction following a reported protocol with slight modification 15 . To a solution of amino acid 1 mmol dissolved in 5 mL of alkali 10 aq NaOH was added sapienoyl chloride dissolved in dichloromethane 5 mL in a drop wise manner and the reaction mixture was stirred for 2 h at room temperature.…”