Structural Effects on the Properties of Nonionic Surfactants. VIII.

Syntheses and Some Surface Active Properties of Acetals from C₁₈-Oxo-Aldehydes and Polyoxyethylene Glycols

Abstract

Branched higher aliphatic aldehydes obtained through oxo-synthesis have been treated with polyoxyethylene glycols using an acid catalyst to give acetal type nonionics : R (CH₂) ₂CH (R) CH [O (C₂H₄O) _m/2H] ₂ (OAG series) and RCH₂CH=C (R) CH [O (C₂H₄O) _m/2H₂] ₂ (OAG^Δ series), R : -CHMeCH₂CMe₃. Cloud point (Cp), aqueous surface tension (γ), cmc and some gross effects of OAG and OAG^Δ were compared with those of nonionics containing comparable hydrophobe : R (CH₂) ₂CH (R) CH₂O (C₂H₄O) _mH (iso series) and CH₃ (CH₂) ₁₇O (C₂H₄O) _mH (S series).
At the same HLB values based on the Davies' group number, Cp of OAG and OAG^Δ were lower than those of iso series. The cmc values increased in the order S<iso<OAG^Δ<OAG. The order of the increase in γ lowering ability was S<<OAG^Δ<OAG≤iso, and wetting powers also increased in this order. OAG and OAG^Δ showed low foaming properties and excellent emulsifying powers. Suspending powers and detergencies of OAG and OAG^Δ were almost comparable to those of iso series. OAG and OAG^Δ were fairly stable in neutral or weakly basic aqueous solution, but easily hydrolyzed under acidic conditions. These facts reveal the possibility of their controlled surface activities depending on the pH of aqueous solution used, to afford some industrial applications.