Synthesis And Properties Of The Conventional Monomeric And The Gemini Surfactants Constructed By Nonylphenoxyacetate

Sodium aliphatate comes from natural source, it is a green surfactant which isnon-toxic, low irritation, and biodegradable. But there are also some disadvantageswhich have limited their application, such as poor solubility at low temperature in pH7,and poor resistance to hard water. The research modify the fatty acid by introducing afunctional group with polarization between the hydrophobic carbon chain andhydrophilic group carboxylic acid sodium. According to report, Gemini surfactants havemuch higher surface activity, that its CMC is lower than traditional surfactants by1or2orders of magnitude. And it has lower Krafft point (TK), better solubility in water andbetter compatibilization, higher wetting power, better resistance to hard water, bettercompatibility and so on. Gemini surfactant is a research hotspot at present, in this paper,to improve the performance of traditional carboxylic acid surfactants, a novelcarboxylate type Gemini surfactants were synthesized.A novel modified soap—sodium2-(4-nonylphenoxy) acetate(SNA) was synthesizedby introducing a phenoxy group into the straight alkyl group of the sodium soap ofordinary fatty acids in this paper, the raw product was purified by recrystallized inethyl acetate. The purity of the product is98%by testing with two phase titration andHPLC measurement. The molecular structure of the product was identified by FT-IR and1H-NMR. Performance of SNA such as TK, surface tension (γ), CMC, wetting time (WT),foam ability, lime soap dispersing agent requirement and emulsifying power weremeasured both at pH7and pH10, the results were further compared with sodium oleate(SOA) and laurylbenzenesulfonic acid (LAS). The results show that SNA has excellentsolubility at low temperature (TK<0°C), excellent pH-independent wettability (WT=25s) compared to SOA (WT>15min); and good concentration-independentdefoamability. In conclusion, SNA’s dependence on pH was dissolved, which made ithave the potential to be a novel low-foaming soap-type penetrating agent.The novel Gemini nonylphenoxyacetate-based surfactant—disodium bis (2-carboxymethoxy-5-nonylphenyl) methane (BCM) was synthesized by directlycarboxymethylating bis (2-hydroxy-5-nonylphenyl) methane (BHNM). The raw productwas purified by recrystallized in ethyl acetate and TLC method, the purity is more than94.5%tested by HPLC. FT-IR,1H-NMR and ESI-MS were used to characterize andidentify the structure of the product. Furthermore, another carboxylate Geminisurfactant—disodium bis (2-carboxy methoxy ethoxy-5-nonylphenyl) methane (BCEM)was synthesized by firstly ethoxylating BHNM and then carboxymethylating it. The rawproduct was purified by recrystallized in ethyl acetate and TLC method, product wascharacterized and identified by FT-IR,1H-NMR and ESI-MS. The results proved that thetarget products (BCM and BCEM) were successfully synthesized. They are newcarboxylate Gemini surfactants.TK, γ, WT, foam ability, calcium stability, lime soap dispersing agent requirementand emulsifying power of BCM and BCEM were tested respectively: Compared with thetraditional surfactant SNA and sulfonate Gemini surfactant-Bis (2-hydroxy-5- nonylphenyl) methane disodium sulfonate (BMS), Gemini nonylphenoxyacetate-basedsurfactants have higher surface activity than SNA and BMS. The CMC of BCM is1.08×10-4mol/L at pH10, while CMC of BCEM is1.43×10-3mol/L at pH7and1.05×10-4mol/L at pH10respectively, both of them are lower than SNA by one orders ofmagnitude. Compared with SNA, BCM has worse solubility in water, no improvementon resistance to hard water, worse wetting power and emulsification. Though wettingpower and emulsification of BCEM are not as good as SNA, but its resistance to salt andhard water is improved, what’s more, it has excellent foaming ability and foamingstability. The results show that the embedded of EO can improve the solubility and hardwater resistance of Gemini nonylphenoxyacetate-based surfactants. Because of itswonderful water solubility, high surface activity, excellent foaming ability and stability,BCEM can be applied in washing field replacing traditional fatty acid sodium.The research successfully improved traditional carboxylate surfactant’s poorsolubility in water under neutral conditions and resistance to hard water, expanded itspotential application. Also conducted further research on synthesis,structure-performance relation about carboxylate Gemini surfactants, which is significantboth to scientific research and application.