Abstract Six cocogem surfactants were synthesized from N,N,Nʹ,Nʹ-tetra-(propane-2-olyl)-1,6-hexanediamine and higher monocarboxylic acids: capric, lauric, myristic, palmitic, stearic and oleic. N,N,Nʹ,Nʹ-tetra-(propane-2-olyl)-1,6-hexanediamine was synthesized from hexamethylenediamine and propylene oxide at room temperature, without utilizing any catalyst or solvent. Surface tension, conductivity, foaming ability, foam stability, emulsion stability, viscosity and density measurements were performed on aqueous solutions of all cocogem surfactants. Their surface activity and colloidal-chemical parameters such as critical micelle concentration (CMC), surface pressure at CMC (πCMC), surface tension at CMC (γCMC), surface excess (Γmax), concentration required for 20 mN/m reduction of surface tension (C20), Gibbs energies of adsorption and micellization (ΔGad and ΔGmic) were recorded and variation of these parameters based on hydrophobic chain length and structure was investigated experimentally and computationally. Synthesized surfactants with myristic, palmitic, and stearic tail continued to decrease surface tension even above CMC. The possible reason of this unusual behavior was determined based on computational studies. Surface activity parameters of cocogem surfactant with oleic tail disobeyed the general tendency established by other cocogems with saturated tail group. Palmitic and stearic acid based cocogem surfactants had good foam stability and the reason of this high foam stability was rationalized with high viscosity of their solutions.

中文翻译：

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基于六亚甲基二胺、环氧丙烷和长链羧酸的新型Cocogem表面活性剂：理论与应用

摘要 以N,N,Nʹ,Nʹ-四-(丙烷-2-油基)-1,6-己二胺和高级一元羧酸：癸酸、月桂酸、肉豆蔻酸、棕榈酸、硬脂酸和油酸为原料合成了六种椰油宝石表面活性剂。N,N,Nʹ,Nʹ-四-(丙烷-2-油基)-1,6-己二胺是由己二胺和环氧丙烷在室温下合成的，不使用任何催化剂或溶剂。对所有 cocogem 表面活性剂的水溶液进行表面张力、电导率、发泡能力、泡沫稳定性、乳液稳定性、粘度和密度测量。它们的表面活性和胶体化学参数，例如临界胶束浓度 (CMC)、CMC 表面压力 (πCMC)、CMC 表面张力 (γCMC)、表面过量 (Γmax)、表面张力降低 20 mN/m 所需的浓度(C20), 记录了吸附和胶束化的吉布斯能（ΔGad 和 ΔGmic），并通过实验和计算研究了基于疏水链长度和结构的这些参数的变化。具有肉豆蔻、棕榈和硬脂尾的合成表面活性剂即使在 CMC 以上也继续降低表面张力。这种异常行为的可能原因是基于计算研究确定的。具有油酸尾的cocogem 表面活性剂的表面活性参数不服从其他具有饱和尾基的cocogem 建立的一般趋势。棕榈酸和硬脂酸基cocogem 表面活性剂具有良好的泡沫稳定性，这种高泡沫稳定性的原因在于其溶液的高粘度。