天然棉籽油臭氧化反应机理及过程研究

Study on Reaction Mechanism and Process for Ozonation of Natural Cottonseed Oil

为了研究天然棉籽油在不同溶剂中的臭氧化反应历程,合成高过氧化值的臭氧化油,以棉籽油为原料,通过臭氧氧化制备了一系列臭氧化油,利用红外光谱(IR)、核磁氢谱(1H-NMR),异核碳氢相关谱(HMQC)和长程异核碳氢相关谱(HMBC)解析了棉籽油中双键臭氧化的反应历程和产物结构,并优化了乙酸乙酯溶剂体系的臭氧化过程的工艺条件。结果表明:乙酸乙酯溶剂中,羰基氧化物与醛反应,主要产物为臭氧化物;而甲醇溶剂中,羰基氧化物易与过量醇发生反应,主要产物为过氧羟基和甲氧基的双官能团产物;在棉籽油的加入量为25 g,进口臭氧浓度80 mg/L,进口流量3 L/min,乙酸乙酯添加量50 g,反应时间2 h下,棉籽油双键转化率可达99%,产物过氧化值为1 990.73 mmol/kg,所获得的臭氧化棉籽油热稳定性好。

To study the reaction process for ozonation of natural cottonseed oil in different solvents and obtain products with high peroxide value, a series of ozonized oil was prepared through ozonolysis using cottonseed oil as raw material. The process of ozonation reaction and structure of resulting products were confirmed by infrared spectrum(IR), nuclear magnetic hydrogen spectroscopy(1 H-NMR), heteronuclear multiple bond correlation(HMBC) and heteronuclear multiple quantum correlation(HMQC), and optimized conditions of reaction in ethyl acetate was obtained. The results showed that the carbonyl oxide could be captured by aldehyde and the main product was ozonide in ethyl acetate solvent, while the carbonyl oxide could be reacted with hydroxyl group to form difunctional product of peroxyhydroxy and methoxy group in methanol solvent. The effects of solvent dosage and ozone flow rate on the ozonation process were investigated and ozonized cottonseed oil with the peroxide value of 1 990.73 mmol/kg and good thermal stability was obtained under the conditions of 25 g cottonseed oil, 50 g ethyl acetate as solvent, ozone concentration 80 mg/L, the flow rate 3 L/min and the reaction time 2 h.