异构脂肪酸酯的响应面法优化合成及柔润性能

Synthesis optimized by response surface methodology and refreshing and moisturizing properties of isomeric fatty acid esters

摘要:

为探索异构脂肪酸酯的绿色合成工艺，揭示油脂的物理化学性质与其对皮肤作用间的关系，以异构脂肪醇与新壬酸为原料，对甲苯磺酸与亚磷酸（物质的量之比为3.05∶1 ）为复合催化剂，通过无溶剂法合成了系列异构脂肪酸酯，采用单因素和响应面法优化模型化合物新壬酸异壬醇酯（ININ）的合成工艺条件。采用FTIR、1HNMR表征确认了ININ的结构，基于表界面张力、接触角、扩散系数、摩擦系数、相容性等物理化学参数的测定，考察异构脂肪酸酯结构对其润湿铺展、滋润、清洁力的影响。结果表明，响应面法优化的ININ的合成工艺条件为：催化剂用量（以新壬酸质量计算的质量百分数）1.44%，醇酸比（异壬醇和新壬酸的物质的量之比）1.16∶1.0，反应温度130.5 ℃，反应时间3.73 h，此条件下，新壬酸转化率为97.17%；系列合成酯均为无色透明无异味，且反应的脂肪酸（正壬酸或新壬酸）转化率均大于95%。多甲基支链化异构脂肪酸酯ININ和新壬酸异十三醇酯（INIT）的表面张力均小于30 mN/m，接触角 低于50°，扩散速率约40 mm/s，与彩妆成分相容性好，可自发在皮肤上铺展，清爽性与清洁力优于传统矿物油及直链壬酸壬醇酯；皮肤涂抹合成的8种脂肪酸酯，静摩擦系数和动摩擦系数分别减少59%、60%以上，新壬酸2-己基癸醇酯具有相对对称的多条疏水链，滋润性更好。

Abstract:

To explore the green synthesis process of isomeric fatty acid esters and reveal the relationship between the physical chemistry properties of oils and their effects on skin. A series of isomeric fatty acid esters were synthesized by solvent-free method using isomeric fatty alcohols and 3,5,5-trimethylhexanoic acid as raw materials, p-toluenesulfonic acid and phosphorous acid (molar ratio 3.05:1) as composite catalysts. The synthesis conditions of model compound isononyl isononanoate (ININ) were optimized by single factor and response surface methodology. The structure of ININ was confirmed by FTIR and 1H NMR. The physical chemistry parameters such as surface interfacial tension, contact angle, diffusion coefficient, friction coefficient and compatibility were determined. The effect of the structure of isomeric fatty acid esters on its wetting, spreading, moistening and cleaning ability was investigated. The results showed that the optimum conditions for the synthesis of ININ were as follows: the amount of catalyst (mass percentage of isononanoic acid) was 1.44%, the conversion of isononanoic acid was 97.17% when the molar ratio of isononyl alcohol to isononanoic acid was 1.16:1.0, reaction temperature was 130.5 ℃ and reaction time was 3.73 h. The synthetic esters were colorless, transparent and odorless, and the conversions of fatty acids were more than 95%. The surface tension of polymethyl branched isomeric fatty acid esters ININ and isotridecyl isononanoate (INIT) was less than 30 mN/m, the contact angle was less than 50°, and the diffusion rate was about 40 mm/s, which had good compatibility with makeup ingredients, can spontaneously spread out on the skin. Freshness and cleanliness superior to traditional mineral oils and linear fatty acid esters. When 8 kinds of fatty acid esters were applied to the skin, the static friction coefficient and dynamic friction coefficient were reduced by more than 59% and 60%, respectively. Isononanoic acid 2-hexyl decanol ester has a relatively symmetrical number of hydrophobic chains and better wettability.