硫酸铵与羟基乙酸混合液中两组分的吸附分离研究

发布时间：2018-05-08 09:01

本文选题：大孔吸附树脂 + 硫酸铵　；参考：《江南大学》2015年硕士论文

【摘要】：羟基乙酸同时兼具酸性、碱性两种性质,在合成生物降解材料、化学清洗剂及日用化工产品等方面得到广泛应用。目前国内企业主要采用羟基乙腈水解法生产羟基乙酸,产品纯度低,无法满足其在有机合成、医药和化妆品行业上的要求,因此亟需建立简单、方便、高效的方法来分离提纯羟基乙酸。本文采用吸附分离技术研究硫酸铵与羟基乙酸混合液中两组分的分离提纯。在吸附过程中硫酸铵比羟基乙酸提前穿透,而在解吸过程中羟基乙酸比硫酸铵延迟解吸。根据此特性,利用大孔吸附树脂对混合液进行吸附及解吸实验,在吸附过程中提纯硫酸铵组分,在解吸过程中提纯羟基乙酸组分,最终达到两组分分离提纯的目的,同时对两组分的吸附进行理论分析,为吸附分离技术在混合液中分离提纯硫酸铵与羟基乙酸的应用提供理论指导。本文主要研究及结论如下:1.硫酸铵与羟基乙酸混合液中两组分的分析方法研究本文在甲醛法、酸碱滴定法基础上引入乙酰丙酮分光光度法,甲醛与乙酰丙酮反应生成有色物质3,5-二乙酰基-1,4-二氢吡啶(DEDHP),测定体系吸光度,改进并建立了混合液中测定硫酸铵和羟基乙酸含量的分析方法:DEDHP分光光度~酸碱滴定联合定量分析法。探讨了硫酸铵含量、羟基乙酸含量、乙醇浓度、p H值、温度、时间等因素对该方法测定两组分含量的影响。该方法适宜条件:p H=5~7,CGA0.9 mg·m L-1,60℃恒温15 min,测定波长414 nm;两组分含量测定的相对偏差分别小于1.5%、1.8%。2.大孔吸附树脂对混合液中两组分的分离研究分别采用动态吸附法及解吸法考察了树脂各性能(极性、孔径、比表面积)对混合液中硫酸铵与羟基乙酸的吸附、解吸规律,以穿透容量差(ΔQ)、硫酸铵纯化率(ηs)、饱和容量差(ΔQe)、羟基乙酸纯化率(ηq)为考察指标,研究吸附过程中硫酸铵的分离及解吸过程中羟基乙酸的分离。根据组分ΔQ与ΔQe的变化规律发现树脂极性越大、比表面积越大或孔径约为160A°时,树脂对两组分的分离能力越强,结合纯化率的变化规律,发现树脂HPD950具有最佳分离效果,并确定了分离提纯的适宜条件,1)吸附实验:40℃,料液流速1.5 m L·min-1;2)解吸实验:40℃,20%的乙醇~水溶液为洗脱液,洗脱流速1.6 m L·min-1。在此条件下,硫酸铵纯化率ηs0.9、ηs1.0(纯度90%、100%)分别约为51、85 mg·g-1,羟基乙酸纯化率ηq0.7(纯度70%,工业级)、ηq0.99(纯度99%,医药级)分别约为262、123 mg·g-1。3.HPD950树脂吸附分离混合液中两组分的机理研究采用静态吸附法研究两组分在树脂HPD950上的吸附行为,考察不同温度、树脂粒径、料液浓度对吸附过程的影响,进行吸附热力学及动力学研究;探究两组分在吸附过程中的吸附机理。热力学研究中,树脂HPD950对硫酸铵的吸附过程符合Langmuir等温吸附模型,对羟基乙酸的吸附过程符合Freundlich等温吸附模型,且均为优惠吸附;两组分的吸附过程均为自发进行(ΔG0)的熵增加(ΔS0)物理放热(ΔH0,|ΔH|40 k J·mol-1)过程。动力学研究中,两组分的吸附均为准二级速率动力学过程,扩散过程由颗粒内扩散控制,动力学总方程分别为:硫酸铵：（RTFCr F ×?ù?é-×××=-+---17499exp0786.0)1(213123/29620.0）羟基乙酸:（tRTFCr F ×?ù?é-×××=-+---20521exp1961.0)1(2)1(3123/22554.）
[Abstract]:Hydroxy acetic acid, which has two properties of acid and alkaline, has been widely used in the synthesis of biodegradable materials, chemical cleaning agents and daily chemical products. At present, hydroxy acetonitrile is used to produce hydroxy acetic acid in domestic enterprises. The purity of the products is low, which can not meet the requirements in the organic synthesis, medicine and cosmetics industry. It is urgent to establish a simple, convenient and efficient method to separate the purified hydroxy acetic acid. In this paper, the separation and purification of two components in the mixture of ammonium sulfate and hydroxy acetic acid are studied by adsorption separation technology. The adsorption and desorption experiments of the mixture with macroporous adsorption resin were used to purify the ammonium sulfate component during the adsorption process and to purify the hydroxy acetic acid component during the process of desorption and finally achieve the purpose of separating and purifying the two components. At the same time, the adsorption of the two components was theoretically analyzed to separate and purify ammonium sulfate and hydroxyl in the mixture solution. The application of acetic acid provides theoretical guidance. The main research and conclusion are as follows: 1. analysis methods of two components in the mixture of 1. ammonium sulfate and hydroxy acetic acid in this paper, the acetacetone spectrophotometric method is introduced on the basis of the formaldehyde method, acid base titration, and the reaction of formaldehyde and acetacetone to produce coloured substance 3,5- two acetyl -1,4- two hydropyridine (DEDH P) to determine the absorbance of the system and to improve and establish an analytical method for the determination of the content of ammonium sulfate and hydroxy acetic acid in the mixture: DEDHP spectrophotometric titration combined with quantitative analysis. The effects of ammonium sulfate content, hydroxy acetic acid content, ethanol concentration, P H value, temperature, time and other factors on the determination of the content of the two components are discussed. Suitable conditions: P H=5~7, CGA0.9 mg. M L-1,60 C at constant temperature 15 min, measuring wavelength 414 nm; the relative deviation of two components content determination is less than 1.5%. The separation of two components in the mixture of 1.8%.2. macroporous adsorption resin is studied by dynamic adsorption method and desorption method, respectively, to investigate the properties of tree fat (polarity, pore diameter, specific surface area) in the mixture. The adsorption and desorption of ammonium sulfate and hydroxy acetic acid, by penetration capacity difference (delta Q), ammonium sulphate purification rate (ETA s), saturation capacity difference (delta Qe) and hydroxy acetic acid purification rate (ETA q) as the investigation index, the separation and desorption of ammonium sulfate in the process of adsorption were studied. According to the variation of delta Q and delta Qe, the greater the polarity of the resin was found, the greater the polarity of the resin. The greater the specific surface area or the diameter of the aperture is about 160A degrees, the stronger the separation ability of the resin to the two components. The optimum separation effect of the resin HPD950 is found, and the suitable conditions for separation and purification are found, and 1) the adsorption experiment is 40, 1.5 m L. Min-1; 2) desorption experiment: 40, 20% ethanol solution is elution Liquid and elution flow rate of 1.6 m L. Min-1., the purification rate of ammonium sulfate, ETA s0.9, ETA s1.0 (purity 90%, 100%), is about 51,85 mg. G-1, the purification rate of hydroxy acetic acid (purity 70%, industrial grade), ETA q0.99 (purity 99%, pharmaceutical grade) is about two components of 262123 mg / g-1.3.HPD950 resin adsorption separation mixture respectively. The adsorption behavior of two components on resin HPD950 was studied by adsorption. The effects of different temperature, resin particle size and concentration of material on the adsorption process were investigated. Adsorption thermodynamics and kinetics were studied. The adsorption mechanism of two components in the adsorption process was investigated. In thermodynamic study, the adsorption process of resin HPD950 to ammonium sulfate was in accordance with Langmuir isothermal absorption. The adsorption process of hydroxy acetic acid conforms to the Freundlich isothermal adsorption model, and the adsorption process is preferential adsorption. The adsorption process of the two components is spontaneous (delta G0) entropy increase (delta S0) physical exothermic (delta H0, Delta H|40 K J. Mol-1). In the kinetic study, the adsorption of the two components is all quasi two rate kinetics process and the diffusion process is from the grain In grain diffusion control, the dynamic equations are: ammonium sulfate: (RTFCr F *?? * * * * * =-+---17499exp0786.0) 1 (213123/29620.0) hydroxy acetic acid: (tRTFCr F * * * * * * * =-+---20521exp1961.0) 1 (2) 1 (3123/22554.)

【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ028;TQ424

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