The Heat Stability of Cationic Surface Active Agents

Synthesis and Properties of Surface Active Agents. XII

Abstract

The thermal decomposition of various types of cationic surface active agents (CSA) with a long chain of alkyl group at 180°C were studied.
The volumetric titration by Sodium Tetraphenylborate using Methyl Orange as an indicator was applied to the analysis of CSA. Other determining methods did not afford the accurate results to the analysis of various types of CSA.
The thermal decomposition rates of C₁₂H₂₅N⁺ (CH₃) ₂C₂H₄OH, A^- containing various anion ; F^-, Cl^-, Br^-, I^-, 1/2 SO₄^--, NO₃^-, H₂PO₄^-, ClO₄^-, CH₃COO^-, CCl₃COO_-, C₁₁H₂₃COO^-, 1/2 (COO^-) ₂, _??_-COO^- and CH₃-_??_-SO₃^- were determined. CSA containing ClO₄^-, CH₃-_??_-SO₃^-, NO₃^- and I^- were superior to others. By arranging CSA of hydrogen halide in the order of heat stability, the following result was obtained ; I^->Br^->>Cl^->F^-. This ordering supports C.K. Ingold's decomposition mechanism of CSA (J. Chem. Soc., 1933, 526). Organic acid salts showed poor heat stability.
Chemical constitution of cationic parts of CSA did not so affect as were anionic parts.