STP875: Phosphorus-Based Anionic Surface-Active Agents and Their Role in Agrochemical Formulations

    Sheridan, GP
    Section Leader, Surfactant & Surface Coatings, Lankro Chemicals Ltd., Eccles, Manchester,

    Pages: 10    Published: Jan 1985


    Abstract

    Phosphorus-based anionic surfactants prepared by reacting an alcohol or an ethoxylate with tetraphosphoric acid (TPA) or with phosphorus pentoxide (P2O5) are complex in structure, yielding differing compositions of mono- and diprotic species of alkyl phosphates. When surfactants prepared from TPA-based product and P2O5-based product are compared, it is seen that whilst the free alcohol content is essentially the same, the monoester content has been considerably increased at the expense of the “diprotic” or polyphosphate species. The properties exhibited by these surface-active agents can be directly attributed to these structural differences and are particularly emphasized in the formulation of agrochemicals. Phosphates prepared using P2O5 can be of significant advantage in the formulation of emulsifiable concentrates and suspension concentrates where the influence of the diprotic species assists emulsion stability and dispersion rheology, whereas the TPA route is preferable in circumstances involving high electrolyte conditions such as fertilizer solutions.

    Keywords:

    phosphorylating agent, tetraphosphoric acid, phosphorus pentoxide, phosphate esters, emulsifier, dispersant, hydrotropic properties, suspension concentrate, fertilizer, active ingredient


    Paper ID: STP32855S

    Committee/Subcommittee: E35.22

    DOI: 10.1520/STP32855S


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