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甘油酯交换反应系指甘油三酯中酰基的重新分配,与两种油脂的机械混合不同,它往往产生一种新油脂品种,理化性能(如熔点、硬度、固体指数、乳化分散性等)和生物价值(营养吸收性、毒性)都发生了很大变化,是现代油脂加工的重要手段,能为食品工业(如人造奶油、起酥油、巧克力糖果等专用油脂)和绿色化妆品提供优质油基原料,同时该技术也大量用于制备生物柴油领域中。近年来,诸多文献报道了利用生物酶催化酯交换反应,但是因为生产成本的原因,大多停留在实验室的研究阶段。目前工业生产中,主要使用碱性醇钠或钠钾合金为催化剂,存在反应条件苛刻(如无水、无氧环境、高速搅拌等)、生产周期长(原料和产物前后处理工作繁琐)、设备投资大、油脂消耗多、生产成本昂贵等问题。在现有的工艺中,微量水分、二氧化碳、氧气、过氧化物都可使催化剂失活而惰性化。一般情况下,水分小于0.01%、酸价小于0.05,使用0.1%醇钠可正常反应。但是水分在油脂中有一定的溶解度,市售精炼油脂含水在0.1%～0.2%,用普通的真空加热方法很难除去。水分使催化剂使用量增加数倍,而且催化剂与水作用生成的碱又加速了油脂的皂化,以致后处理困难,油脂收率低。为防止空气中氧气的作用,需充氮气或真空操作,增加了设备投入。醇钠为极性固体,难溶于油脂,为增大反应接触面,往往需要高速搅拌分散。国外也有用二甲亚砜作溶剂的,它的缺点是毒性大,不宜用于食品加工。本文使用了比较安全的多元醇作助催化剂,较好地解决了上述问题。
Glycerol transesterification refers to the redistribution of acyl groups in triglycerides. Unlike the mechanical mixing of two types of fats, it tends to produce a new type of fats and oils with physical and chemical properties (such as melting point, hardness, solid index, emulsifiability, etc.) and Biological value (nutrient absorption, toxicity) have undergone great changes, is an important means of modern oil processing, the food industry (such as margarine, shortening, chocolate candy and other special grease) and green cosmetics to provide high-quality oil-based raw materials , While the technology is also used extensively in the field of preparing biodiesel. In recent years, many reports on the use of bio-enzyme-catalyzed transesterification, but mostly because of the cost of production, stay in the laboratory research phase. At present, the industrial production mainly uses sodium alcoholate or sodium-potassium alloy as catalyst, which has harsh reaction conditions (such as anhydrous, anaerobic environment and high-speed stirring), long production cycle (cumbersome processing of raw materials and products before and after treatment), equipment Big investment, more oil consumption, high production cost and other issues. In the prior art, trace amounts of moisture, carbon dioxide, oxygen and peroxide can inactivate and inactivate the catalyst. Under normal circumstances, the water is less than 0.01%, acid value less than 0.05, the use of 0.1% sodium alcohbite normal reaction. However, water has some solubility in fat, commercially available refined oil containing water in the 0.1% to 0.2%, with ordinary vacuum heating method is difficult to remove. Moisture to increase the amount of catalyst used several times, and the role of the catalyst and water generated alkali accelerated the saponification of oil, resulting in post-processing difficulties, low fat yield. To prevent the role of oxygen in the air, to be filled with nitrogen or vacuum operation, an increase of equipment investment. Sodium alkoxide is a polar solid, insoluble in oil, in order to increase the reaction contact surface, often require high-speed stirring dispersion. Foreign also useful as a solvent dimethyl sulfoxide, its disadvantage is toxic, not suitable for food processing. This paper uses a relatively safe polyol as a co-catalyst, a better solution to the above problems.