Hydrotropic properties of a novel alkylnaphthalene sulfonate

Alkylbenzenesulfonates based on toluene, xylene, as well as cumene, and alk ylnaphthalenesulfonates, act as hydrotropes in surfactant systems. A novel sodium diisopropylnaphthalene sulfonate (SDIPNS) has been developed that co ntains about 92% diisopropylnaphthalene sulfonate, compared to other diisop ropylnaphthalene sulfonate preparations that contain less than 50% diisopro pylnaphthalene sulfonate. This material is both a hydrotrope and a surfacta nt. The color of a 35% solution is light yellow, Gardner 3, significantly l ighter than comparable materials. Draves wetting time for a 0.5% solution i s about 30 s. The Ross-Miles foam test (1% solution) indicates a significan t level of initial foam, but the foam is unstable. The solubilities of tolu ene and limonene in SDIPNS are much higher than in other hydrotropes tested . Hydrotropes raise the cloud point of nonionic surfactants; SDIPNS is the most efficient hydrotrope found for this application. Another measure of hy drotropicity is the amount of hydrotrope required to clear a cloudy deterge nt formulation; this hydrotrope is quite effective. Another measure is the modification of surfactant formulation viscosity; SDIPNS is quite effective . Additionally, SDIPNS changes the solubility of nonionic surfactants in wa ter. SDIPNS is a surfactant as well as a hydrotrope, demonstrating a critic al micelle concentration at about 1%.