An Economical Method for Preparative Purification of Five Alkaloids from Coptis Chinensis Franch by High-Speed Counter-Current Chromatography Using Singled Prepared Solvent System by GC

Coptis chinensis Franch, a widely used Traditional Chinese Medicine, shows various kinds of bioactivity. The major active components of the herb are considered to be alkaloids. Thus, preparative separation of these alkaloids is critical important for further pharmacology and mechanism studies. In the paper, five alkaloids from C. chinensis were purified by HSCCC using the solvent system composed of chloro-form-metha- nol-water (2:1:1, v/v/v) single prepared. The content of each solvent in solvent system were determined by gas chromatography (GC), then according the ratios of solvents in each phase to prepare the mobile and stationary phase respectively. And a comparative study was carried out between together preparation and single preparation of the solvent system. The purities and recoveries of all the products were over 98.5% and 92%. However, 134 mL chloroform, 336 mL methanol and 452 mL water were saved when the two phase were singled by GC. Our research showed an economical method for separating alkaloids from C. chinensis by HSCCC using the solvent system single prepared by GC.

Separation and Purification of Acetophenones from Cynanchum bengei Decne Root Bark by Combination of Silica Gel and High-speed Counter-current Chromatography

[Objectives] To develop a method for separation and purification of acetophenones from Cynanchum bengei Decne root bark by combination of silica gel and high-speed counter-current chromatography( HSCCC). [Methods]The crude extract of Cynanchum bengei Decne root bark was separated by silica gel column chromatography,and parts A and B containing acetophenones were obtained. Then,parts A and B were separated by HSCCC with a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water( 4∶ 6∶ 4. 5∶ 5. 5 and4∶ 6 ∶ 3 ∶ 7, V/V), respectively. [Results] From 260 mg of part A, four compounds with p-dihydroxybenzene 3. 9 mg(Ⅰ),4-hydroxyacetophenone 17. 1 mg( Ⅱ),2,5-di-hydroxyacetophenone 13. 3 mg(Ⅲ) and 2,4-dihydroxyaceto-phenone 21. 0 mg(Ⅳ) were obtained. And from 300 mg of part B,136 mg of Radix Cynanchi Bungei benzophenone(Ⅴ) was obtained. The purity of compounds determined by HPLC was 97. 0%,96. 6%,99. 2%,99. 7%,99. 5%,respectively. [Conclusions] The established method is simple and efficient. It can be used for separation of acetophenones from Cynanchum bengei Decne root bark and has better practical value,which could provide a reference basis for development and utilization of Cynanchum bengei Decne root bark.

Comparison of Co-Current and Counter-Current Flow Fields on Extraction Performance in Micro-Channels

Several applications such as liquid-liquid extraction in micro-fluidic devices are concerned with the flow of two immiscible liquid phases. The commonly observed flow regimes in these systems are slug-flow and stratified flow. The latter regime in micro-channels has the inherent advantage that separation of the two liquids at the exit is efficient. Recently extraction in a stratified counter-current flow has been studied experimentally and it has been shown to be more efficient than co-current flow. An analytical as well as a numerical method to determine the steady-state solution of the corresponding convection-diffusion equation for the two flow-fields is presented. It is shown that the counter-current process is superior to the co-current process for the same set of parameters and operating conditions. A simplified model is proposed to analyse the process when diffusion in the transverse direction is not rate limiting. Different approaches to determining mass transfer coefficient are compared. The concept of log mean temperature difference used in design of heat exchangers is extended to describe mass transfer in the system.

Preparative isolation and purification of 12,13-dihydroxyeuparin from Radix Eupatorii Chinensis by high-speed counter-current chromatography

An efficient method for the isolation and purification of 12,13-dihydroxyeuparin from Radix Eupatorii Chinensis by high speed counter-current chromatography (HSCCC) was established in this paper. The ether extracts of Radix Eupatorii Chinensis were purified by HSCCC with a solvent system of hexyl hydride-ethyl acetate-methanol-water (1:2:1:2, v/v/v/v). The upper phase was used as the stationary phase and the lower phase as the mobile phase. About 8.4 mg of 12, 13-dihydroxyeuparin was obtained from 200 mg of ether extracts from Radix Eupatorii Chinensis in one-step HSCCC separation, with the purity of 96.71%, as determined by HPLC. After methanol- water recrystallization, the purity of 12,13-dihydroxyeuparin reached 99.83%. Such a simple and effective method was fairly useful to prepare pure compound as reference substances for related study on Radix Eupatorii Chinensis.

Isolation and Purification of Isoaloeresin D and Aloin from Aloe vera by High-speed Counter-current Chromatography

Objective To develop an efficient method to isolate and purify the main components isoaloeresin D and aloin from Aloe vera for its industrial production.Methods High-speed counter-current chromatography was used to isolate isoaloeresin D and aloin in a one-step separation from dried crude extract of A.vera.The biphasic solvent system composed of hexane-ethyl acetate-acetone-water(0.2:5:1.5:5) was used at a flow rate of 1.0 mL/min,while the lipophilic phase was selected as the mobile phase and the apparatus was rotated at 840 r/min.The effluent was detected at 254 nm.Results Isoaloeresin D(53.1 mg) and aloin(106.9 mg) were separated from the crude extract(384.7 mg) with the purities of 98.6% and 99.5%,respectively.Conclusion HSCCC is a powerful technique for isolation and separation of chemical composition from aloe.

Modeling the axial hydrodynamics of gas-solid counter-current downers

Gas-solid counter-current downer reactors,in which particles move downward in an upward gas flow,can achieve high solid concentration for high heat and/or mass transfer rates.However,the particles may reverse their direction or even be carried out of the reactor as the gas flow rate increases.This is closely related to "flooding" in counter-current flows.The energy minimization multiscale (EMMS) model well describes multiscale heterogeneity in gas-solid cocurrent upward flows.It is further developed to simulate gas-solid counter-current downward flows because similar heterogeneity can also be found in downers.The model characterizes well the axial hydrodynamics and predicts an inflexional voidage variation with superficial gas velocity in the fully developed region.This is supported by a simulation based on computational fluid dynamics and the discrete element method.The flooding predicted by the model agrees better with experiment than previous models.

Modeling of co-current and counter-current bubble columns with an extended EMMS approach

Bubble columns can be operated in semi-batch, co-current or counter-current mode. This study attempts to extend the dual-bubble-size (DBS) model, viz., the energy-minimization multi-scale (EMMS) model for gas-liquid systems, to co-current and counter-current bubble columns. With the increase of superficial liquid velocity, the predicted total gas holdup and regime transition are in accordance with experiments. A DBS drag model was then developed and incorporated into the CFD simulation. The total gas holdup and local gas holdup radial distribution in both the co-current and counter-current bubble columns are well estimated. The findings in the present work demonstrate that developing closure laws through the stability condition is of great significance in modeling complicated multi-scale flow in bubble columns.

Preparative Separation of Four Alkaloids from Gelsemium elegans by High-speed Counter-current Chromatography

Objective To develop an efficient preparative method for the separation of Gelsemium alkaloids from Gelsemium elegans. Methods High-speed counter-current chromatography （HSCCC） with several two-phase solvent systems was investigated for the separation of Gelsemium alkaloids. The purity and structure identification of the purified compounds were performed with HPLC and NMR spectra, respectively. Results In a single operation, 206.6 mg of crude alkaloid sample was separated to yield 28.7 mg of koumine, 24.9 mg of gelsemine, 26.9 mg of humantenine, and 7.2 mg of gelsevirine, with the purities of 97.8%, 95.4%, 97.4%, and 93.5%, respectively. Conclusion A preparative HSCCC method is successfully established for the separation of four Gelsemium alkaloids from G. elegans with a modified two-phase solvent system com posed of n-hexane-ethyl acetate-ethanol-O. 5% triethylamine-H2O （3：5：3：4）.

Counter-current three-phase fluidization in a turbulent contact absorber： A CFD simulation

A computational fluid dynamics study of three-phase counter-current fluidization occurring in a turbu- lent contact absorber was performed. A two-dimensional, transient Eulerian multi-fluid model was used, in which the dispersed solid phase was modeled employing a kinetic theory of granular flow. The grid independence of the model, the effect of wall boundary conditions, the choice of granular temperature model, the effects of order of discretization scheme and drag models were studied for a base case setting, The results of simulations were validated against experimental results obtained from the literature. Once the model settings were finalized, simulations were performed for different gas and liquid velocities to predict the hydrodynamics of the absorber. Computed bed expansion and pressure drop were compared with experimental data. Good agreement between the two was found for low velocities of gas and liquid.

Application of high-speed counter-current chromatography coupled with high performance liquid chromatography for the separation and purification of Quercetin-3-O-sambubioside from the leaves of Nelumbo nucifera

Quercetin-3-O-sambubioside[Quercetin-3-O-β-D-xylopyranosyl(1→2)-β-D-glucopyranoside]was separated and purified by semi-preparative high-speed counter-current chromatography(HSCCC)with a twophase-solvent system composed of ethyl acetate-nbutanol-water(4∶1∶5,v/v)from the leaves of Nelumbo nucifera(Lotus).A total of 5.0 mg of the targeted compound with a purity of 98.6%as determined by high performance liquid chromatography(HPLC)was obtained from 100 mg of the crude extract cleaned up by AB-8 macroporous resin in a one-step separation.Quercetin-3-O-sambubioside was a novel flavonoid glycoside from the leaves of Nelumbo nucifera,and its chemical structure was identified by means of ESI-MS,1D NMR and 2D NMR.

AN EFFICIENT AND TARGET-ORIENTED SAMPLE ENRICHMENT METHOD FOR PREPARATIVE SEPARATION OF MINOR ALKALOIDS BY PH-ZONE-REFINING COUNTER-CURRENT CHROMATOGRAPHY

A sample enrichment method focusing on the minor targeted components was established to help them to be successfully separated by pH-zone refining CCC.Seven minor indole alkaloids in Uncaria rhynchophylla(Miq.)Miq.ex Havil(UR)were chosen to show the advantage of this method.The sample enrichment and separation were

Numerical Simulation of Wet Particles Motion in a Vertical Powder Dryer

In this study,the motion of wet particles in the drying unit of a vertical powder dryer is investigated by using a Discrete element method(DEM)coupled with a liquid bridge force.In particular,by varying parameters such as the particle mass flow rates,the superficial gas velocities,and superficial gas temperatures,the influence of the moisture content on the flow behavior is examined.The results show that when the moisture content increases,the mean particle velocity decreases while the bed mean solid“holdup”and the mean residence time(MRT)of particles grow.It is also found that the local solid holdup is relatively higher in the near-wall region and decreases towards the near-fluid region.Two regression models are introduced accordingly for the mean particle velocity and the bed mean solid holdup by means of the RSM-BBD(Response surface methodology-Box-Behnken design)method to obtain the optimal combination of parameters for flooding prevention.Finally,the optimal results are compared with numerical observations.As the relative error is less than 10%,this demonstrates that the proposed methodology can accurately describe the particle flow dynamics in the drying unit.

蜘蛛网流道冷板冷却液对向流锂离子电池散热分析

锂离子电池工作温度过高或温差过大将导致其容量降低和寿命缩短。为了降低其工作温度及温差,设计了一款蜘蛛网流道冷板,采用数值方法对其冷却液对向流锂离子电池散热进行了计算。比较了蜘蛛网流道冷板冷却液对向流与同向流锂离子电池的散热情况,分析了冷却液流量以及冷板内流道夹角、槽深、壁厚对电池散热的影响。结果表明:与冷却液同向流电池相比,冷却液对向流电池最高温度、温差都降低,电池温度分布更加均匀。在0.02~0.06 kg/s区间,随着冷却液流量增大,电池最高温度和温差快速降低,而冷却液压降缓慢增大;当冷却液流量大于0.06 kg/s时,随着冷却液流量增大,电池最高温度和温差缓慢降低,而冷却液压降快速增大。增大流道夹角可使流道在冷板内分布更加均匀,提高冷板散热能力。当冷却液质量流量恒定时,增大流道槽深可使冷却液压降显著减小,但会引起电池最高温度和温差略微升高。随着流道壁厚增大,电池最高温度和温差均呈下降趋势。蜘蛛网流道冷板在流道夹角80°、槽深1 mm、壁厚2 mm、冷却液流量0.06 kg/s对向流冷却条件下,可使锂离子电池3C放电最高温度和温差降至31.02℃和4.54℃。

废炼油催化剂酸浸液中镍的选择性萃取

针对废炼油催化剂酸浸液中的镍,研究了以HBL110为萃取剂进行直接选择性萃取。优化了萃取剂皂化率、萃取剂浓度、萃取平衡时间,确定了萃取与反萃取级数,并进行了实验室多级逆流串联萃取模拟试验及线上流程的连续萃取试验。结果表明:在皂化率40%、HBL110浓度25%、萃取时间10 min条件下,经五级逆流萃取,萃余液中镍质量浓度低于30 mg/L,镍萃取率达98%以上,Al、Fe萃取率低于3%;以75 g/L硫酸对镍负载有机相进行三级逆流反萃取可100%实现镍的反萃取;对废催化剂酸浸液进行线上萃取流程连续运行5 d,萃余液中镍质量浓度稳定在5 mg/L,镍萃取率达99%,反萃取液中镍质量浓度稳定在8 g/L,镍反萃取率为100%,有机相可以实现有效的循环再利用。

无患子皂苷连续管式逆流超声辅助提取的釜式微分模拟研究

借助工业生产(行业)公认的“萃取”扩展定义,以尊重原理、“化繁为简”、“实施可行”的理念,对无患子皂苷连续管式逆流超声辅助提取的工艺过程展开了“釜式微分提取”的模拟研究。结果表明,不同提取阶段的提取液皂苷含量与其相对应的进料液皂苷含量之间的函数关系为Y=0.0188x^(4)-0.0389x^(3)-0.2866x^(2)+0.6108x+1.4536,R^(2)=0.7108。从数理统计学的角度,可以将它看作是“连续管式逆流超声辅助提取无患子皂苷的动力学行为关系”。

钢管密闭塔水平圆管降膜热质传递规律研究

冷却塔通过热质交换将高温介质的热量从系统排放到大气,从而达到冷却效果。对钢管密闭式冷却塔水平圆管降膜蒸发器传热传质的影响因素进行研究与分析,搭建逆流式密闭塔水平圆管降膜传热传质性能研究可视化实验台,主要研究气流速度、喷淋密度、喷淋水温度对横管降膜蒸发传热传质性能的影响。在给定实验工况下,得出当最佳喷淋密度为0.0416 kg/(m·s),对应的最大总换热系数为1625.01 W/(m^(2)·K);当最佳喷淋水温度为16.82℃,对应的最大总换热系数为1736.86 W/(m^(2)·K);最佳气流风速在1~2 m/s之间。

城市轨道交通计轴设备受干扰分析及解决方案

城市轨道交通系统采用交流供电模式时常发生牵引供电回流干扰计轴设备的问题,针对该问题,分析计轴系统工作原理,对某市域轨道交通线路发生计轴设备受扰问题进行监测、试验、分析,并提出有效的解决方案。

利用锌浸出渣制备铊吸附剂

火法冶金工序中,含铊物料易挥发进入烟气洗涤工序,从而产生了大量含铊废水,带来环境污染风险;同时,铅锌行业每年产出总量达数百万吨以ZnFe2O4为主要成分的浸出渣废料,需要妥善处置。基于此,本文提出以锌浸出渣为原料,通过酸浸法提取其中的有价值元素锌和铁,通过氨络合选择性沉铁工艺实现锌铁分离,最后将沉铁产物经过冷冻干燥处理,制得铁基铊吸附剂。稀硫酸逆流浸出法处理锌浸出渣可实现较高的锌、铁浸出效率,分别达到97.05%、99.31%,得到的浸出液中锌、铁浓度分别为86.54 g/L、77.86 g/L;采用本研究提出的络合沉淀法选择性沉铁工艺可以将浸出液中99.78%的铁沉淀分离,且锌损失率控制在0.5%;冻干处理后的沉铁产物是优秀的铁基铊吸附剂,3 g/L铊的水溶液中铊去除率为98.9%,采用pH值1.5的稀盐酸可以洗脱95%的吸附铊,为铊的进一步回收和资源化利用提供了有利条件。该工艺不仅实现了对锌浸出渣的绿色、高值化回收利用,而且成功制备出性能优异的铊吸附剂。

杭州地铁1号线计轴红光带问题分析及解决方案

[目的]在杭州地铁1号线三期区段动车调试及试运行过程中,在线路不同位置处,计轴设备均出现了受扰异常占用(红光带)的情况,严重影响了地铁的运营安全。因此,有必要对异常受扰场景进行分析和测试试验,选择合适的改进方案解决计轴设备的受扰异常占用问题。[方法]介绍了列车通过1号线三期计轴区段异常受扰占用情况;分析了列车牵引设备回流与计轴设备干扰谐波之间的关系,并进行了相关调查测试及验证;提出了列车牵引设备与计轴设备工作频段重叠产生干扰谐波的解决方案。[结果及结论]对于1号线三期工程列车通过三期计轴区段异常受扰占用(红光带)情况,可采用优化列车牵引系统设备工作频率参数的方法解决该问题,错开列车牵引设备工作频段与计轴设备工作频段,以解决设备的同频干扰问题。

变频冷水机组在轨道交通的应用能效分析

地铁车站的人流量密集,舒适度要求高,是人们生活中极为重要的公共建筑。本文以深圳地铁12号线的新安公园站、左炮台站、福永站3个站点的空调系统为研究对象,从DeST的负荷模拟、机组性能曲线、运行的实测数据等方面对串联逆流超磁螺杆机组、永磁同步变频螺杆机组、永磁同步变频离心机组、机房和系统进行能效分析。结果表明,应用串联逆流技术的超磁螺杆机组能效较高,5-11月份其主机COP、EERs、TCOP分别达到8.52,7.10,4.05。