Self-Assembly and Phase Behavior of New (α-Hydroxyalkyl)phosphorus Amphiphiles

Abstract

A new series of (R-hydroxyalkyl)phosphinic acids 1 was prepared in good yields from long-chain aldehydes (C8-C18) and 50% aqueous hypophosphorous acid under sonication. Oxidation of these phosphinic acids by dimethyl sulfoxide in the presence of catalytic amounts of iodine afforded the corresponding (R-hydroxyalkyl)phosphonic acids 2. Critical micelle concentrations (cmc) of the amphiphilic monocaternary (R-hydroxyalkyl)phosphorus acid ammonium salts 1 and 2, determined by tensiometry and 31 P NMR, showed a good correlation between the two methods and indicated their high surfactant properties. The phosphonate salts 2 with two dissociable groups had much higher cmc values than those of the corresponding phosphinate analogues 1. The ammonium salts of these phosphorus acids were able to form ordered lyotropic mesophases in concentrated water solutions, visualized by optical polarization microscopy. The nature of the observed mesophases (hexagonal or lamellar) depended on the concentration, the temperature, the nature of the polar head, and the length of the alkyl chain, the hexagonal phase being promoted for shorter chains (C8 and C10). The ability of these acids 1-2 to form stable and compact Langmuir monolayers at the air/water interface was studied. Their conformations at the air/water interface were estimated by a molecular modeling study.

Flotation performances and adsorption mechanism of α-hydroxyoctyl phosphinic acid to cassiterite

“…For FTIR, XPS Page 3 of 29 A c c e p t e d M a n u s c r i p t 3 and Zeta potential measurements, the finer fraction (-5μm) was used. HPA was synthesized according to Albouy's approach in our lab [11,12]. DPA, SPA, benzohydroxamic acid (BHA) and salicylhydroxamic acid (SHA) was purchased from commercial companies with a purity of 85%.…”

“…The phosphorous compounds such as phosphonic and phosphinic acids own characteristic chelating properties and could be applied as extractants in recovery and separation of some metal ions such as lanthanides, actinides and cobalt [12,13]. As applied in mineral processing, styrene phosphonic acid (SPA) and diphosphonic acid (DPA) have been adopted as collectors for flotation recovery of metal oxide minerals [14,15].…”

Self‐Assembly of Methacrylate‐Functionalized Phosphonate and Phosphate Amphiphiles and their Conversion into Nanospheres

“…Organophosphorus acids and esters are compounds with many important biological and pharmacological properties. For example, long‐chain phosphonate esters can be considered as analogues of phospholipids, the main components of biological membranes 1. During the past few years, organophosphonates and ‐phosphate amphiphiles have received increasing attention because of the diversity of their aggregate microstructures, that is, micelles, vesicles and lamellar phases 2, 3.…”

“…However, only a few studies on the synthesis and aggregation behavior of phosphorus‐containing amphiphiles have been published as yet. Investigations of self‐assembled monolayers of dodecyl phosphate and hydroxy‐terminated dodecyl phosphate,4 single‐chain polypropenyl phosphates,5 or the micellization of α ‐hydroxyalkylphosphonic acid salts1 and poly(ethylene glycol) phosphates6 have been reported in the literature. Most of these studies focused on the self‐association properties and the phase behavior of the reported molecules.…”

Novel Modified Pyrrole Monomers, 2: Behaviour in Water Solutions

“…Schultz et al [20] investigated the phase behaviour of alkane phosphonic acid/water systems. Recently, attention was paid to the investigation of self-organisation properties of α-hydroxy-, as well as α-amino alkyl phosphonic acids in solution [21][22][23].…”