多酚酸酯稳定剂对生物柴油高温稳定性的影响

Influence of Polyphenolic Acid Esters as Stabilizer on High-temperature Stability of Biodiesel

根据110℃时生物柴油的酸值随时间的变化规律,研究多酚酸酯稳定剂种类、稳定剂质量分数以及协同增效剂对生物柴油高温稳定性的影响。选择的多酚酸酯稳定剂包括:6种没食子酸萜醇酯(没食子酸金合欢酯、没食子酸香叶酯、没食子酸芳樟酯、没食子酸橙花叔醇酯、没食子酸薄荷酯和没食子酸氢化松香酯)、5种没食子酸烷基酯(没食子酸甲酯、没食子酸丙酯、没食子酸辛酯、没食子酸月桂酯和没食子酸十八酯)、3种合成抗氧化剂(BHT、BHA和TBHQ)、2种天然抗氧化剂(茶多酚和迷迭香抗氧化剂)。研究表明6种没食子酸萜醇酯对生物柴油高温稳定性作用相差不大,其中没食子酸香叶酯的高温稳定化效果略好;5种没食子酸烷基酯稳定剂中,没食子酸甲酯对生物柴油高温稳定化的效果较好;3种合成抗氧化剂对生物柴油高温稳定性作用也相差不大;天然抗氧化剂茶多酚对生物柴油高温稳定性作用略好于迷迭香抗氧化剂。当改变稳定剂质量分数时,没食子酸芳樟酯和没食子酸橙花叔醇酯质量分数0.12%时高温稳定化能力较好,没食子酸甲酯、没食子酸金合欢酯和没食子酸薄荷酯质量分数0.08%时高温稳定化能力较好。协同增效剂柠檬酸未能改善生物柴油的高温稳定性。

The influences of variety of polyphenolic acid ester stabilizers and mass fraction of stabilizers on high-temperature stability of biodiesel were studied according to the relationship of acid value of biodiesel with time at 110 ℃. The selected stabilizers included six terpenyl gallates （farnesyl gallate, geranyl gallate, linalyl gallate, nerolidyl gallate, menthyl gallate and hydroabietyl gallate）, five alkyl gallates （methyl gallate, propyl gallate, octyl gallate, dodecyl gallate and octadecyl gallate）, three synthetic antioxidants （BHT, BHA and TBHQ） and two natural antioxidants （tea polyphenols and rosemary antioxidant）. The results showed that there were slight differences among six terpenyl gallates on high-temperature stability of biodiesel. Geranyl gallate was slightly better. Methyl gallate had a stronger ability to stabilize biodiesel among five alkyl gallates. The difference of three synthetic antioxidants on high-temperature stability of biodiesel was also small. The ability of tea polyphenots to stabilize biodiesel was slightly stronger than that of rosemary, antioxidant. The abilities of high-temperature stabilization to biodiesel of linalyl gallate and nerolidyl gallate at mass fraction 0.12 % , methyl gallate, farnesyl gallate, and menthyl gallate at mass fraction 0.08 % were preferred. The synergistic agent citric acid could not improve high-temperature stability of biodiesel.