Critical review on analytical methods for biodiesel characterization
Critical review on analytical methods for biodiesel characterization
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DOI：
10.1016/j.talanta.2008.07.001
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发表时间：
2008-12
期刊：
影响因子：
6.1
通讯作者：
M. Monteiro;A. Ambrozin;L. Lião;A. Ferreira
中科院分区：
文献类型：
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作者：
M. Monteiro;A. Ambrozin;L. Lião;A. Ferreira
生物柴油是一种由单烷基酯组成的替代燃料，主要由油脂的碱催化酯交换反应获得。它的使用（纯的或混合的）不需要对柴油发动机和现有的燃料分配和储存基础设施进行任何修改。此外，生物柴油具有高能量产量，固定太阳能，并含有微量的硫。因此，生物柴油是目前化石柴油的最佳替代品。除单烷基酯外，甘油（主要副产物）、醇、催化剂、游离脂肪酸、三酸甘油酯、二酸甘油酯和单酸甘油酯构成生物柴油生产过程的最终混合物。这些和其他种类的污染物可导致严重的操作和环境问题。因此，生物柴油的质量控制对于其商业化的成功和市场接受度具有重要意义。生物柴油质量控制的一些重要问题涉及酯交换反应的监测，单烷基酯和游离和键合甘油的定量以及残留催化剂和醇的测定。此外，混合水平的测定是生物柴油分析的另一个关键方面。色谱法和光谱法是最常用于生物柴油表征的分析方法，但也可使用基于物理性质的程序。以前，Knothe撰写了一份关于用于评估生物柴油质量的分析方法的综述。由于这一领域的重要性，我们对Knothes的评论进行了更新。因此，在本文中，我们将描述生物柴油分析的新进展和Knothes论文中的一些参考文献。特别是，我们将描述用于定量甘油，甘油单酯，甘油二酯，甘油三酯，甲醇，水，钠，钾，磷和类固醇在生物柴油或沿着酯交换反应的分析方法。同时，对生物柴油掺混物中生物柴油含量的测定和一些理化参数的测定进行了讨论。最后，我们将评估现有的技术，并指出一些改进的分析方法的生物柴油表征。
Biodiesel is an alternative fuel composed of mono-alkyl esters and obtained mainly from the base-catalyzed transesterification reaction of oils or fats. Its use (pure or blended) does not demand any modification in the diesel engine and in the existing fuel distribution and storage infrastructure. Moreover, biodiesel has a high energetic yield, fixes the solar energy and contains insignificant amounts of sulphur. Therefore, biodiesel is currently the best substitute for fossil diesel fuel. Besides mono-alkyl esters, glycerol (main co-product), alcohol, catalyst, free fatty acids, tri-, di- and monoglycerides compose the final mixture of biodiesel production process. These and other kinds of contaminants can lead to severe operational and environmental problems. Therefore, the quality control of biodiesel is greatly significant to the success of its commercialization and market acceptance. Some important issues on the biodiesel quality control involve the monitoring of transesterification reaction, the quantification of mono-alkyl esters and free- and bonded glycerol as well as determination of residual catalysts and alcohol. Moreover, the determination of blend levels is another key aspect of biodiesel analyses. Chromatography and spectroscopy are the analytical methods most used for the biodiesel characterization, but procedures based on physical properties are also available. Previously, a review on analytical methods used to evaluate biodiesel quality was written by Knothe. Due to the importance of this field, we made an update of Knothes’ review. Therefore, in this paper, we will describe new developments in biodiesel analyses and some references showed in Knothes’ paper. Specially, we will describe analytical methods used for quantification of glycerol, mono-, di-, triglycerides, methanol, water, Na, K, P, and steroids in biodiesel or along the transesterification reaction. Also, the determination of biodiesel content in blends and some physicochemical parameters are discussed. At the end, we will assess the available techniques and point out some improvements on analytical methods for biodiesel characterization.