The Study Of Performances Of Didecylmethylammonium Salts With Different Counterions

Cationic surfactants are widely used in construction, oil exploitation, mining, printing, dyeing and daily chemical industry, and its varieties are plentiful, while the quantity is less in the total output of surfactants. The alkyl agent mainly with chloromethane, benzyl chloride, bromomethane, iodomethane and dimethylsulfate. So the counterions of traditional quaternary ammonium salts(QAS) are confined to Cl-, Br- and CH3SO4-. The limitation of alkyl agent not only limits the varieties of QAS, but also has a bad influence on operator, product and environment. So it is important to serach a green, non-toxic quaternization reagent. As the grown of dimethyl carbonate (DMC), the DMC has become an interest in the worldwide. DMC can be used as a quaternization reagent to sythesis methyl carbonate quaternary ammonium salt (MCQAS) with fatty amine, and MCQAS can be react with different acids to sythesis corresponding acid. This method expands the varieties of QAS effectively. In order to explore the influence of the counterions on application performance and further practice, we selected the didecyl tertiary amines, DMC and corresponding acids as raw materials to synthesis QAS with different counterions. And the physical-chemical properties and application performances of the synthesized QAS are measured and applied in sanitizer formula.In this paper, we selected the didecyl tertiary amines. DMC and different acids as raw materials to sythesis 10 didecyldimethylammonium salts with different counterions. The purified products were characterized by IR and 1H-NMR. The results indicated the didecyldimethylammonium salts we successfully synthesised with the counterions are HCOO, CnH2n+1COO(n=1,2,3,5,7,9,11), Cl and NO3, respectively.The surface tension, foaming properties, emulsifying properties, wetting properties and antibacterial properties of the 10 different counterion QAS are measured. The results showed that the critical micelle concentrations (CMC) and surface tension of QAS with carboxylate counterions measured by ring method and pendent drop method had little difference. When the counterion was inorganic ion or the alkyl chain carbon number was less than 6, the counterion had less influnence on CMC. When the counterions of long carbon alkyl chain, which had great influence on CMC of QAS.Because of the different counterions, didecyldimethylammonium salts showed different foam properties. The foam property (foaming properties and foam stability) of didecyldimethylammonium nitrate (DDAN) was better than the foam property of didecyldimethylammonium chloride (DDAC). With the increase of counterion carbon chain length, the foam property of QAS showed increase at first, then decrease. This indicated we can control the foam property of QAS by changing the counterions.The emulsifying property of DDAN was better than the emulsifying property of DDAC. With the increase of counterion carbon chain length, the emulsifying property of QAS showed increase at first, then decrease, when the counterion carbon chain length is 6, the didecyldimethylammonium salts showed best emulsifying property.The wetting property of DDAN was better than the wetting property of DDAC. With the increase of counterion carbon chain length, the wetting property of QAS gradually increase.The 10 didecyldimethylammonium salts we sythesized all showed excellent antibacterial properties against E. coli and S. aureus.We chose didecyldimethylammonium formate (DDAF) mixed with mild, safe sodium fatty alcohol ether carboxylate (AEC-9Na). The surface activities and application properties of DDAF and AEC-9Na mixed systems were measured. The results showed the mixed systems had the synergism on CMC, surface tension, emulsifying and wetting properties. The foaming abilities of mixed systems are better than single surfactant DDAF, while the foam stabilities of mixed systems showed lower than DDAF, which suggested the AEC-9Na/DDAF mixture can be used for low-foam systems in washing machines.In addition, the mixed systems showed both better detergency and excellent antibacterial properties, which may be provide a data support on liquid detergent contains antibacterial property.Sanitizer as one of the daily supplies, which not only clean the hand skin but also inhibit bacteria. DDAF as an antibacterial materials used in sanitizer formula, the sanitizer formula as follows:BS-12 (2.0%), APG (3.0%), AEO (1.0%),6501 (3.0%) and DDAF (0.2%), supplemented the thickener, humectant, showed better comprehensive sensory quality. The sample showed good stablility and nonirritating, which can reach the standard of special hand cleaner GB 19877.1-2005.