工业碳酸钠提纯实验

对工业碳酸钠进行提纯研究,经溶解、过滤、蒸发结晶、灼烧等步骤,制备出纯度较高的碳酸钠,并对所得最终产品进行杂质含量分析。试验结果表明,经提纯后的碳酸钠其纯度和杂质含量要求均达到国标GB 210.1中Ⅱ类一等品指标要求。加入活性炭吸附剂提纯工业碳酸钠,所得提纯效果较好。使用滤布过滤进行提纯,可提高过滤速度且不影响提纯效果。提纯回收率可达94.4%。     

异山梨醇提纯及未知杂质结构研究

针对异山梨醇高效液相色谱保留时间为17～18min时产生的杂质进行了研究。首先通过减压蒸馏和结晶等方式对异山梨醇产品进行后处理。当减压精馏切除前馏分为30%时,该杂质可去除。乙酸乙酯结晶除杂效果更佳。其次对异山梨醇产品进行液质联用检测,并结合相关文献对检测结果进行分析,初步断定杂质结构和该杂质产生原因。最后提出在生产过程中控制该杂质的方法。     

镀液杂质的去除

众所周知,镀液的科学管理和维护对于稳定生产和保证产品质量是十分重要的。镀液的科学管理和维护的一个重要方面,就是监测镀液被杂质的污染,随耐除去杂质,保证正常生产。镀液在配制和使用过程中会受到杂质的污染。这些杂质可来自以下几方面:(1)阳极。电镀中因阳极不纯而带入杂质的情况常会遇见。不纯锌阳极常混有铅,镍阳极中会含有微量铜。(2)化学药品。电镀中采用的化学药品多半为工业级,含杂质的允许范围较大。所以在选购时要注意规格,以便在配制镀液时对症下药,加以处理。有时,工厂生产中的意外事故也会给原料带进意想不到的杂质。例如,工业碱是用熔盐膜式蒸发器生产的,因管道腐蚀穿     

DSD酸的杂质分析及提纯方法研究

本文对DSD酸粗品中的杂质进行了定性分析,提出了利用二次结晶工艺对DSD酸工业粗品进行提纯的方法,并对提纯过程中各种因素对产品质量的影响进行了分析,确定了提纯工艺的优化条件:在pH 6～7、温度80～83℃及避光条件下进行二次结晶,得到的产品纯度大于99.6%.     

高纯无机盐制备中杂质离子的去除与分离

介绍了在制备高纯无机盐过程中,有害杂质离子——重有色金属离子(Cu、Mg、Zn、Pd、Cd等)、铁离子、砷化物的去除与分离方法:氧化-还原法、难溶金属氢氧化物沉淀法、硫化物沉淀法。     

银杏叶提了以物杂质去除方法的研究

根据银杏叶中各垢性质,探讨用沉淀剂去除其中鞣质,蛋白质等杂质,以达到银杏扣提取物中黄酮衍生物的含量,使其大于２４％。     

煤化工高盐水中无机杂质协同去除技术研究

面向煤化工高盐水资源化处理的技术需求,结合钙、镁、硅、氟等杂质大量共存的水质特点,实验研究了一条以两步法化学沉淀（加碱调pH沉淀,加碳酸钠沉淀）为主的无机杂质协同去除技术路线。结果表明,在控制pH≥11.1的条件下,化学沉淀可将钙、镁、硅协同去除至20、5、4.7 mg/L以下;选择氢氧化钙调pH还可同时取得显著除氟效果,但氟离子去除率随原水硫酸根浓度在16.1～64.3 g/L间的递增而由93.0%逐渐下降至62.2%。当协同除氟不能满足产水要求时,验证了增加一步铝盐絮凝沉淀将氟离子除至20 mg/L以下的可行性。     

碳酸锂的制备及其纯化过程的研究进展

近年来,随着锂离子电池的广泛应用及动力汽车产业的兴起,锂的需求量逐年增加. 碳酸锂作为一种最重要的基础锂盐,在锂离子电池中广泛应用,主要用于合成锂离子电池正极材料. 目前,高纯碳酸锂主要通过从矿石提锂浸出液或盐湖卤水中经过纯化工艺制备. 纯化方法主要包括碳化法、苛化法、电解法、碳酸锂重结晶法及离子交换法等. 但碳酸锂制备和纯化过程中存在诸多问题,如锂钠的深度分离、高纯碳酸锂的制备等. 本工作对碳酸锂制备及纯化方法进行综述,指出了碳酸锂制备及纯化过程中存在的主要问题及未来的发展方向.     

电池级碳酸二甲酯提纯工艺研究

采用高效精馏技术,并添加自制添加剂,提纯得到电池级碳酸二甲酯,产品质量分数达99.9%以上,水分含量小于10mg/kg。     

Viscoelastic Behavior of Alkyl Ether Sulfate Systems Containing Sodium Carbonate

Relaxation behaviors in systems containing sodium alkyl ether sulfate and sodium carbonate were studied. The anionic surfactants were commercial grade systems with average chain lengths of twelve carbons and either one, two, or three ethoxy (EO) groups. It was found that viscosity maxima in the three systems were achieved at particular salt levels that increased with an increase in the number of EO groups. Relaxation of the optimized systems was studied by measuring the complex, storage and loss moduli as a function of frequency. Temperature was varied between 5 and 45 °C. While characterization of relaxation in terms of the Maxwell model adequately described data below the threshold of ωτ < 1, the model failed to adequately describe behavior at higher frequencies. A modified expression with an additional Rouse relaxation mode adequately described relaxation throughout the frequency range studied. Temperature dependencies provided estimates of activation energies which were consistent with literature values for reptation modes of relaxation. No temperature dependencies were seen for the second relaxation mode of the model. Studies of ultrasonic attenuation in the surfactant system determined that attenuation increased in systems with higher EO content. Relaxation times were additionally found to decrease with increased EO content. This implied that diffusion in the compressive relaxation modes was more dependent on the sizes of the micellar structures as opposed to the sizes of the individual surfactant molecules.     

电位滴定法测定工业烧碱中氢氧化钠和碳酸钠的含量

目前GB／T4348．1—2000测定工业用氢氧化钠中氢氧化钠和碳酸钠含量时,采用的是化学滴定法,但是此方法存在耗时耗试剂等一系列缺点,不符合现代分析化学发展的趋势,而自动电位滴定法操作方便,测定快速准确,有利于实现化学分析的自动化。本实验用瑞士Metrohm682电位滴定仪对大量样品进行测定,数据表明,电位滴定法的准确度和精密度可以满足国标的要求,可用自动电位滴定法代替化学滴定法。     

Solid Bridge Formation Between Spray-Dried Sodium Carbonate Particles

Moisture migration caking of pharmaceutical excipients in the absence of load is a significant quality and stability issue. This study uses Atomic Force Microscopy (AFM) to examine a solid bridge formed between two 20 µm spray-dried sodium carbonate particles. The bridge is grown by repeatedly exposing the system to 70% RH and 30% RH cycles at 25°C. A comparison is made with the idealized bridge model developed by Tanaka (1978), which was previously verified using crystalline systems. The resulting system was found to be more complex and grew in two stages. The first stage consisted of linear growth to five cycles, followed by a more gradual expansion and the appearance of crystalline structures.     

无水硅酸钠催化酯交换合成碳酸二甲酯

以廉价的Na2Si O3·9H2O为原料,通过简单的焙烧处理,制备了系列无水硅酸钠,并将其作为固体碱催化剂应用于碳酸乙烯酯(EC)与CH3OH酯交换合成碳酸二甲酯(DMC)的反应。采用TG-DTA、XRD和Hammett指示剂法对无水Na2Si O3进行表征。结果表明,焙烧温度对无水Na2Si O3的碱强度、总碱量及催化活性没有显著影响。当焙烧温度为200℃时,样品(Na2Si O3-200)的碱强度(Ho)为15.0~18.4,总碱量为10.9 mmol/g。以Na2Si O3-200为催化剂,考察了原料配比、温度和时间对酯交换合成DMC反应的影响。当CH3OH与EC的摩尔比为10∶1,在65℃反应2 h后,EC转化率与DMC收率可分别达到89%和88%。即使在室温条件下,Na2Si O3-200也能有效地催化EC与甲醇酯交换反应的进行。此外,经过4次使用后,Na2Si O3-200的催化活性没有出现明显下降的趋势。     

六偏磷酸钠的生产工艺

本文对六偏磷酸钠的性质、用途及生产工艺进行论述并介绍从日本引进１．５ｋｔ／ａ食品级六偏磷酸钠生产装置投产运行情况。     

Thermogravimetric Analysis and Chemical Kinetics for Regeneration of Sodium and Potassium Carbonate Solid Sorbents

In this study, nonisothermal kinetic methods for the decomposition of potassium hydrogen carbonate (KHCO₃) and sodium hydrogen carbonate (NaHCO₃) were investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG). Four different heating rates were measured to calculate the order of reaction (n), preexponential factor (A), and activation energy (E_a) using four different models: Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), Kim–Park, and analytical methods. The results showed that the analytical method provided highly accurate results compared with the experimental data, whereas KAS, FWO, and Kim–Park methods gave less accurate results due to the approximation of employed equations. The order of the decomposition reaction of KHCO₃ and NaHCO₃ was approximately 2. The preexponential factor of KHCO₃ was slightly higher than NaHCO₃. The obtained kinetic parameters from those four methods then were used to calculate the chemical reaction conversion for further applications.     

过氧碳酸钠稳定剂的研究

通过实验探索了一种以聚丙烯酸钠为主要成分的稳定剂在过氧碳酸钠生产制备中的应用,并确定了一个稳定性能最佳的稳定剂配方及其制备工艺。     

酯交换法合成碳酸二苯酯的工艺进展

综述了酯交换法合成碳酸二苯酯(DPC)的常见工艺路线,指出了碳酸二甲酯(DMC)和苯酚酯交换合成路线是当前的研究热点,并对一步法工艺和两步法合成DPC的工艺路线作了详尽的介绍;对产品的后续提纯方面进行归纳总结,阐述了减压精馏法和结晶分离法的研究现状。最后对各个工艺路线的优缺点进行了简要总结与对比。