Synthesis of Surfactants Based on Pentaerythritol. I. Cationic and Zwitterionic Gemini Surfactants

Abstract

Simple strategies for the synthesis of five series of cationic gemini surfactants and one series of zwitterionic gemini surfactants from pentaerythritol have been developed. Two lipophilic groups were introduced onto pentaerythritol by alkylation of the known compound, O-benzylidenepentaerythritol, with 1-bromooctane, 1-bromodecane, 1-bromododecane, and 1-bromotetradecane. Hydrogenolysis of the benzylidene acetals gave diols which were converted into three different series of trimethylammonium derivatives. The diiodides derived from the diols could be displaced by dimethylamine, even though they are adjacent to a quaternary carbon atom. Alkylation with methyl iodide gave the first series. The iodides were easily displaced by cyanide ion and the resulting dinitriles were hydrolyzed, converted to N,N-dimethylamides, and reduced to give a second series. Oxidation of the diols to dialdehydes under Swern conditions followed by Horner−Wadsworth−Emmons reactions with diethyl N,N-dimethylcarbamoylmethylphosphonate followed by two-stage reduction gave a third series. The dialkoxides derived from the four di-O-alkylpentaerthritol diols were reacted with 2-dimethylaminoethyl chloride and 3-dimethylaminopropyl chloride in neighboring-group assisted double Williamson ether syntheses to give precursors to two more series. As expected because the neighboring group participation occurs through a four-membered-ring intermediate, considerably more vigorous conditions were required for the reactions with 3-dimethylaminopropyl chloride. 2-Diethylaminoethyl bromide was found to be less reactive than 2-dimethylaminoethyl chloride. The products were alkylated with methyl iodide and, in some cases, other alkyl halides to give cationic gemini surfactants. Alkylation of one series with ethyl bromoacetate followed by anion exchange resin catalyzed ester hydrolysis gave zwitterionic gemini surfactants. The members of all series have superior surfactant properties.

Properties of binary surfactant systems of nonionic surfactants C12E10, C12E23, and C12E42 with a cationic gemini surfactant in aqueous solutions

“…Their unique chemical structure offers a model system to study the systematic variations in the hydrophobic/hydrophilic character that affect the solution properties and makes them suitable for mixing with other surfactants [2,3]. Gemini surfactants, made up of two polar headgroups and two hydrophobic tails covalently connected through a spacer group at or near the headgroups are attracting considerable interest in both academic and industrial research [4][5][6][7][8][9][10][11][12][13][14]. They have been widely used in the fields of soil remediation, enhanced oil recovery, drug entrapment and release, gene therapy, etc.…”

Influence of Spacer Nature on the Aggregation Properties of Anionic Gemini Surfactants in Aqueous Solutions

“…Gemini surfactants are made up of two hydrophobic chains and two polar head groups covalently attached through a spacer at the level of the head groups or very close to these groups [1]. They are of current interest owing to their superior properties compared with those of conventional ionic surfactants [2][3][4][5][6][7][8][9][10][11]. They have low critical micelle concentration (CMC) and C 20 (surfactant concentration in the solution phase that will reduce the surface tension of the solvent by 20 mN m -1 ) [1][2][3][4]10].…”

Asymmetric cationic gemini surfactants: an improved synthetic procedure and the micellar and surface properties of a homologous series in the presence of simple salts

“…Gemini, or dimeric surfactants, have two matching head groups connected by a linking chain, the most common being an alkylene chain; [1][2][3][4][5][6][7][8] the hydrophobic tails of the head groups may be the same (symmetric gemini surfactant) or different (asymmetric gemini surfactant). The symmetric members of the cationic gemini surfactants listed in the above references are the most commonly studied in the literature, [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] whereas anionic, [25][26][27][28][29][30][31] zwitterionic, [32][33][34] and nonionic gemini [35][36][37] surfactants are comparatively less studied.…”