Synthesis and properties of double epoxy groups double quaternary ammonium salts

Abstract

Double epoxy group double quaternary ammonium salts (DEpDQAS) were synthesized by epichlorohydrin (ECH) reacting with N,N,N'N'-tetramethylethylenediamine (TMEDA) and N,N,N'N'-tetramethyl-1,6-hexanediamine (TMHDA), respectively. The results of orthogonal experiments showed that temperature and time were the key factors influencing on epoxy value and quaternarization ratio respectively. The optimal condition for higher epoxy value was the reaction temperature at 15 °C and methanol as solvent. The reaction kinetic process was determined by conductivity, which showed that the reaction had a short induction period and appeared discontinuity in progress that the reaction rate of the first stage was almost constant, while the reaction rate of the second stage decreased gradually. The product was characterized by infrared spectroscopy (FTIR) and nuclear magnetic resonance (¹H NMR). The results of surface tension testing showed that DEpDQAS-6 with longer spacer chain had better surface activity and lowered the solution surface tension to 26 mN·m⁻¹ at 25 °C and CMC 0.27 mol·L⁻¹. The thermodynamic parameters of micellization were obtained basing on charged pseudo-phase model. The studies of cytotoxicity in vitro and antibacterial activity showed that DEpDQAS was biocompatible and its antibacterial activity was more effective against Escherichia coli than against Staphylococcus aureus.

Graphical Abstract

Keywords:

• Double quaternary ammonium
• cationic surfactant
• double epoxy
• antibacterial activity
• biocompatible

Additional information

Funding

This work was supported by the Key Research and Development Program of Shandong Province under Grant [Number 2018GGX108002]; Natural Science Foundation of Shandong Province under Grant [Number ZR2020MB071]; and Open Project Program for State Key Laboratory Base of Eco-chemical Engineering (Qingdao University of Science & Technology) under Grant [Number STHG 2002].