Knowledge Management System Of Institute of process engineering,CAS
氨基酸镁（钙，铁，锌，和铝）等氨基酸金属络合物，是一种有效的生物和动植物金属补充剂。其中，甘氨酸镁因其具有良好的化学和生物稳定性，高吸收率等优点，而广泛用于医药保健品、食品添加剂、饲料添加剂、化妆品添加剂等领域，并逐渐显现出了巨大的经济价值。目前，该类化合物的工业制备方法鲜有报导，从有限的资料看到，氨基酸络合物的合成方法主要是采用水溶剂合成法，虽然该方法具有产率高的优点，但是也有反应周期长、难过滤、产品有结晶水等缺点。鉴于此，本论文提出了利用控制溶液过饱度的方法制备二水和无水甘氨酸镁的新工艺。新方法具有产品易过滤、蒸发耗能减少和甘氨酸镁产品形貌可控等优点，为工业化生产奠定了科学基础。论文取得如下重要结果：（1）以甘氨酸和氧化镁（或氢氧化镁）为原料，在80℃的温度条件下，利用水溶剂合成法可以成功制备二水甘氨酸镁产品。同时，随着反应物浓度的提高，二水甘氨酸镁产品的晶型可以得到不断改善，颗粒粒径也逐渐增大。当使用过饱和甘氨酸溶液进行反应时，二水甘氨酸镁产率显著提高，得到的产品颗粒粒径范围在10~50μm之间，易于过滤，也使整个工艺的水蒸发量大大减少。 （2）实验证明文献报导的在乙醇等有机溶液中直接制备无水甘氨酸产品是很难实现的，但商品化学试剂是无水甘氨酸镁。本论文利用高温干燥二水甘氨酸镁的方法，成功制备了无水甘氨酸镁。热重分析可以看出，二水甘氨酸镁的结晶脱水温度约为150℃，当干燥温度过高时，产品会由白色变为黄色而变质。（3）通过测定二水甘氨酸镁在水溶液中的镁离子浓度即溶解度，结合OLI软件MSE（Mixed Solvent Electrolytes）模型计算水的活度和相关例子的活度系数，首次得到二水甘氨酸镁的溶度积常数Ksp和二水甘氨酸镁的基本热力学性质数据：标准焓变?Hr0为-10.7 kJ·mol-1，标准熵变?Sr0为-102.831 J·mol-1·K-1，298.15K下的吉布斯自由能 为19.96 kJ·mol-1。（4）采用动态法分别测定AlCl3·6H2O晶体在NaCl?CaCl2?NH4Cl?H2O体系和Li2SO4·H2O晶体在Na2SO4?MgSO4?H2SO4?H2O体系的溶解度数据。通过数据拟合建立了混合电解质计算模型（MSE模型），在OLI软件平台基础上可以严格计算电解质溶液的过饱和度，为利用结晶技术制备优质产品提供了科学基础。;Amino acid metal complexes such as amino acids magnesium (calcium, iron, zinc, and aluminum) are effective metal supplements in the interest of biological, animal, and botanical applications. Among them, magnesium glycine acetate has been widely used in medical and health products, food additives, feed additives, cosmetic additives due to its stable chemical and biological properties, high absorption rate, along with other identified advantages to show great economic values. At present, there are few reports on the industrial preparation of such compounds. Analysis of the limited data provided demonstrated that the synthesis method of amino acid complexes is mainly the synthesis of water systems. Although this method has the advantages of leading to a high yield rate, it is proven to be disadvantageous due to a prolonged reaction cycle, hardness of filtration, and the formation of the unwanted crystal water. In view of this, this paper proposed a novel process for the preparation of dihydrate and anhydrous magnesium glycine using a method managed to control the supersaturation of the solution. The new method not only ameliorates the difficulty of filtration, it also significantly reduced the energy consumption for evaporation, ultimately leads to the formation of magnesium glycine products with ideal morphologies. This research laid a scientific foundation for the production of magnesium glycine products within the broad field of chemical engineering. Altogether, the research reported on the following remarkable results:(1) Magnesium oxide (or magnesium hydroxide) and glycine are used as raw materials, and at 80 ℃, magnesium glycine dihydrate can be prepared by hydrothermal synthesis?process. With the increase of the reactant concentration, the crystal form of the magnesium glycine dihydrate product is significantly improved, and the particle size is gradually increased. When a supersaturated glycine solution is used for the reaction, the yield of magnesium glycine dihydrate is significantly improved, and the particle size range is between 10 and 50 μm. The obtained product is easy to filter which reduces the total energy consumption through evaporation and concentration.(2) Experiments have proved that it is difficult to achieve direct preparation of anhydrous glycine products in organic solutions such as ethanol, but the chemical reagent purchased is magnesium glycine. In this dissertation, the high temperature drying method is used to realize the preparation from dihydrate to anhydrous magnesium glycine. Thermogravimetric analysis unveils that the crystallization dehydration temperature of magnesium glycine dihydrate is about 150 ℃. When the drying temperature exceed this level, the product appearance tends to change from white to yellow.(3) By measuring the magnesium ion concentration of magnesium glycine in an aqueous solution, that is: solubility, and by combining the MSE (Mixed Solvent Electrolytes) model of OLI software enables the accurate calculation of the water activity and the activity coefficient of species included, the solubility product Ksp of magnesium glycine dihydrate is obtained for the first time. The basic thermodynamic properties of the constant Ksp and magnesium glycine dihydrate are: ΔHr0= -10.7 kJ·mol-1, ΔS r0 = -102.831 J·mol-1·K-1, ΔG0 f, 298.15K =19.96 kJ·mol-1.(4) Solubility data of AlCl3·6H2O in NaCl?CaCl2?NH4Cl?H2O system and Li2SO4·H2O in Na2SO4?MgSO4?H2SO4?H2O system were determined by dynamic methods. By tuning the newly-regressed interaction parameters for electrolytes, a new MSE model was constructed. Based on the OLI software platform, the supersaturation of the electrolyte solution can be strictly calculated, which grounds a scientific base for preparing high-quality products through crystallization technology.
|曾祥钊. 无水和二水氨基乙酸镁的制备及相关体系热力学模型[D]. 中国科学院大学,2020.|
|Files in This Item:|
|无水和二水氨基乙酸镁的制备及相关体系热力（3336KB）||学位论文||限制开放||CC BY-NC-SA||Application Full Text|
|Recommend this item|
|Export to Endnote|
|Similar articles in Google Scholar|
|Similar articles in Baidu academic|
|Similar articles in Bing Scholar|
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.