生物柴油降凝剂的合成及性能研究

发布时间：2018-04-30 18:04

  本文选题：生物柴油 + 降凝剂　； 参考：《东北石油大学》2015年硕士论文

【摘要】：生物柴油(Biodiesel)是指用可循环的植物油或动物油制备的具有长链脂肪酸的脂肪酸甲酯,它被认为是环保的生质燃料生物柴油。但生物柴油的凝点和黏度都相对矿物柴油较高,低温流动性较差,因而要实现生物柴油的广泛使用,必须改善其低温流动性。本文根据改良剂分子的烷基侧链的碳原子数与生物柴油中脂肪酸链平均碳原子数相等或相近的原则,采用两步法,以丙烯酸、甲基丙烯酸、高级长链醇为原料,以对甲基苯磺酸为酯化催化剂,对苯二酚为阻聚剂,合成了中间体丙烯酸酯和甲基丙烯酸酯;再用丙烯酸酯和甲基丙烯酸酯、乙酸乙烯酯、顺丁烯二酸酐或马来酸酐为原料,过氧化苯甲酰为催化剂,合成了两种生物柴油降凝剂:聚丙烯酸酯和聚甲基丙烯酸酯,并确定了两种降凝剂的合成条件,考察了所合成的降凝剂对生物柴油的降凝效果。在聚丙烯酸酯降凝剂合成的过程中,考察了原料用量、反应温度、反应时间等因素对酯化、聚合反应的影响,并采用红外光谱手段对降凝剂进行了表征。结果表明:在丙烯酸酯:顺丁烯二酸酐:乙酸乙烯酯的摩尔比为4:1:4、反应温度85~90℃、反应时间6h、甲苯用量20mL、引发剂过氧化苯甲酰的加料量为每摩尔丙烯酸酯加5g,降凝效果最好。反应过程中顺丁烯二酸酐用量和温度对降凝效果的影响相似,均是随着顺丁烯二酸酐用量和温度的增加降凝效果呈先上升后下降的趋势,而乙酸乙烯酯的用量则不会影响降凝效果。在聚甲基丙烯酸降凝剂制备的过程中,考察了原料种类、原料用量、温度等因素对降凝剂降凝效果的影响。实验结果表明:在反应温度为110~120℃,反应时间为5h,催化剂对甲苯磺酸添加量为1.0%(质量百分数,下同),长链烷基醇与甲基丙烯酸的摩尔比为1:1.2,阻聚剂对苯二酚的添加量为0.9%的条件下首先合成甲基丙烯酸酯;然后在反应原料摩尔比为:甲基丙烯酸酯:马来酸酐:乙酸乙烯酯为4:4:1,反应温度85~90℃,反应时间为5h的条件下合成的聚甲基丙烯酸酯降凝剂具有较好的降凝效果。将上述制备的两种降凝剂以1%的添加量加入到五种不同原料制备的生物柴油中,生物柴油的凝点可降低4~9℃,冷滤点可降低2~6℃,说明所制备的降凝剂对不饱和脂肪酸和饱和脂肪酸含量较高的生物柴油均具有较好的低温流动性改善性能。
[Abstract]:Biodiesel (Biodiesel) is a kind of fatty acid methyl ester with long chain fatty acids prepared from recycled vegetable oil or animal oil. It is considered as a biofuel biodiesel for environmental protection. However, the freezing point and viscosity of biodiesel are higher than that of mineral diesel, and the low temperature fluidity is poor. Therefore, in order to realize the wide use of biodiesel, it is necessary to improve its low temperature fluidity. According to the principle that the number of carbon atoms in the alkyl side chain of the modifier molecule is equal or similar to the average carbon atom number of fatty acid chain in biodiesel, the two-step method is used to use acrylic acid, methacrylic acid and high grade long chain alcohol as raw materials. The intermediate acrylate and methacrylate were synthesized with p-methylbenzenesulfonic acid as esterification catalyst and hydroquinone as polymerization inhibitor, and then acrylic ester and methacrylate, vinyl acetate, maleic anhydride or maleic anhydride were used as raw materials. Two kinds of biodiesel depressants, polyacrylate and polymethacrylate, were synthesized using benzoyl peroxide as catalyst. The synthetic conditions of the two depressants were determined, and the depressant effect of these depressants on biodiesel was investigated. In the process of synthesis of polyacrylate depressant, the effects of raw material dosage, reaction temperature and reaction time on esterification and polymerization were investigated, and the depressant was characterized by infrared spectroscopy. The results show that when the molar ratio of acrylic ester: maleic anhydride to vinyl acetate is 4: 1: 4, the reaction temperature is 8590 鈩，

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