多酚酸酯稳定剂对生物柴油室温稳定性的影响

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

室温条件下,测定了含不同多酚酸酯稳定剂的生物柴油过氧化值6个月内随时间的变化曲线。用于研究的23种稳定剂,包括:5种没食子酸烷基酯、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)、3种合成抗氧化剂、2种天然抗氧化剂、3种双组分稳定剂、2种三组分稳定剂以及2种含协同增效剂的稳定剂。结果显示没食子酸甲酯对生物柴油的室温稳定化作用明显强于其它4种没食子酸烷基酯、6种没食子酸萜醇酯、3种合成抗氧化剂和2种天然抗氧化剂;没食子酸金合欢酯对生物柴油的室温稳定化作用强于其它5种没食子酸萜醇酯;双组分稳定剂和三组分稳定剂等复合组分稳定剂没有明显改善生物柴油的室温稳定性;含协同增效剂的稳定剂能提高生物柴油的室温稳定性,协同增效剂柠檬酸的作用特别明显;杂质铁和杂质铜会降低生物柴油的室温稳定性,且杂质铁的影响大于杂质铜。

The variation curves of peroxide value of biodiesels containing different kinds of polyphenolic acid esters as stabilizer at room temperature during six months were determined. Twenty-three kinds of stabilizers including five alkyl gallates, six terpenyl gallates （ such as farnesyl gallate, geranyl gallate, linalyl gallate, nerolidyl gallate, menthyl gallate, and hydroabietyl gallate）, three synthetic antioxidants, two natural antioxidants, three bicomponent stabilizers, two tricomponent stabilizers, and two stabilizers containing synergistic agents, were studied. The results showed that methyl gallate obviously had a stronger ability to stabilize biodiesel at room temperature than those of other four alkyl gallates, six terpenyl gallates, three synthetic antioxidants, and two natural antioxidants. Farnesyl gallate had a stronger ability to stabilize biodiesel at room temperature than those of other five terpenyl gallates. Composite stabilizers, such as bicomponent stabilizer and tricomponent stabilizer, could not markedly modify room-temperature stability of biodiesel. The stabilizers containing synergistic agent, especially citric acid, could markedly improve room-temperature stability of biodiesel. Iron and copper impurities could decrease room-temperature stability of biodiesel and the influence of iron impurity was larger than that of copper impurity.