液相色谱技术测定葡萄糖果糖在Ca型吸附剂上相平衡常数和总传质系数

 ]考虑轴向扩散的影响，导出液相色谱技术测定吸附相平衡常数和总数传质系数参数估值模型，测定葡萄糖果糖吸附相平衡常数和总传质系数，研究流速、温度对这些参数的影响。获得理论计算与色谱分离实验流出曲线相吻合结果。     

连续环状色谱分离木糖—山梨糖混合溶液的研究──轴向扩散系数和总传质系数的辨识

本文提出了连续环状色谱分离过程的参数辨识方法，包括其轴向扩散系数的辨识模型，以惰性物ＣａＣｌ２作示踪剂，００１×７树脂为填料，采用扰动－应答法技术在环状色谱床中测定轴向扩散系数。考虑轴向扩散的作用，建立了线性吸附平衡体系的相平衡常数及总传质系数的辨识模型，并对木糖──山梨糖体系，采用扰动－应答技术测定相平衡常数及总传质系数。考察了操作因素对轴向扩散系数与总传质系数的影响规律。结果表明，流速增加，轴向扩散系数加大，环状色谱床中的流动明显地偏离理想活塞流；流速增加，总传质系数也相应增大。     

吸附剂性能和操作参数对液相色谱流出峰不对称性的影响

色谱流出峰的拖尾现象普遍存在于制备和大型色谱分离过程中,它直接影响分离的产率和回收率．本文提出采用色谱流出峰形的不对称偏差度来表征色谱流出峰的拖尾程度;并基于液相制备色谱分离过程FAD－SMT模型及吸附速率理论,通过计算机模拟,定量分析了吸附剂性能和操作参数对色谱流出峰形不对称性的影响。结果表明：不仅是吸附剂的热力学和动力学性能（包括吸附相平衡关系、液固两相间的传质阻力）;而且柱的设计和吸附剂的装填状况（包括轴向扩散系数）,以及色谱分离的操作条件（进料时间、浓度和流速等）都直接影响色谱流出峰形的不对称性。随着吸附相平衡等温线的非线性程度增大,或者总传质系数的减小,色谱流出峰形的不对称偏差度明显增大;吸附剂吸附容量的减小也将引起色谱流出峰形的不对称偏差度的增加;色谱流出峰形的不对称偏差度与进科体积、浓度和流体线速,以及轴向扩散系数的增大成正比。     

连续旋转环状色谱的数学模型参数分析

 连续旋转环状色谱用数学模型模拟时,模拟结果的精确度和所采用参数的“灵敏”程度有关。为此,探讨了相平衡常数、相间传质系数、弥散返混系数等对色谱峰质量浓度最高点位置角度（保留值）、分离度、峰宽和产率等参数的灵敏度并对它们逐一进行了分析。认为相平衡关系对分离效果最为敏感。筛选吸附量大、选择性好的吸附剂是改进操作效果的最佳途径。     

柱吸附容量对蔗糖还原糖色谱分离过程产率和回收率的影响

本文采用了能反映流体轴向扩散的大型液相色谱分离过程数学模型,应用计算机模拟分析蔗糖和还原糖的色谱分离过程,从吸附剂吸附容量和柱装填密度两个方面;考察柱吸附容量对大型色谱分离的产率和回收率的影响。研究结果表明：在色谱柱中流体线速度恒定的条件下对多组分分离,回收率是随吸附剂吸附容量以及床层装填密度的增大而增大的;产率先随吸附剂吸附容量的增大而增大,而在出现峰值后下降;随着床层装填密度的增大,产率增加,但与此同时轴向扩散系数也增大,从而降低分离效率,导致在较高装填密度的范围内产率增力。的幅度减少。在相同的吸附剂用量下,采用短柱高装填密度的色谱柱将比长柱低装填密度色谱柱能获得更高的回收率和产率。     

大型液相色谱分离过程FAD－SMT数学模型及其数值解

提出大型液相色谱分离过程ＦＡＤ－ＳＭＴ数学模型，把色谱分离连续性方程转变为对流扩散方程和常微分方程组，并提出模型的数值方法，分析了数值解的稳定条件和收敛条件以及空间和时间步长的选取。实验结果表明，ＦＡＤ－ＳＭＴ数学模型计算的液相色谱分离葡萄糖、果糖和分离甘露醇、山梨醇理论与实验流出曲线相吻合。灵敏度分析结果表明：相平衡常数比轴向扩散系数和总传质系数对色谱分离有较大的影响。     

大型液相色谱分离过程FAD－SMT数学模型及其数值解

 提出大型液相色谱分离过程ＦＡＤ－ＳＭＴ数学模型，把色谱分离连续性方程转变为对流扩散方程和常微分方程组，并提出模型的数值方法，分析了数值解的稳定条件和收敛条件以及空间和时间步长的选取。实验结果表明，ＦＡＤ－ＳＭＴ数学模型计算的液相色谱分离葡萄糖、果糖和分离甘露醇、山梨醇理论与实验流出曲线相吻合。灵敏度分析结果表明：相平衡常数比轴向扩散系数和总传质系数对色谱分离有较大的影响。     

液相制备吸附色谱流出峰对称性的若干影响因素

 在色谱分离连续性方程和质量传递速率方程基础上，对色谱分离过程进行计算机模拟，定量分析了分离体系的热力学、动力学参数和操作条件对色谱流出峰形对称性的影响。结果表明，吸附相平衡关系、液固两相间的传质阻力及进料体积、进料浓度和流体线速等都将直接影响色谱流出峰形的对称性。流出峰形的不对称程度随着吸附等温线的非线性程度、液固两相间的传质阻力、流体线速、进料体积、进料浓度的增大而增大；在线性条件下，随着吸附剂吸附容量的减小而增大。     

色谱法测定氧和氮在13X分子筛上的吸附平衡常数及传质系数

以H_2作载气,在微机辅助下用色谱法测定O_2和N_2在13X分子筛填充柱上的吸附平衡常数和传质系数。提出用计算量小的矩量法求吸附平衡常数,再由时域拟合单参数估算总传质系数。由实验结果及理论分析发现,该体系中,轴向扩散对总传质阻力贡献最大,并得轴向扩散系数与操作条件的关联式     

流动注射分光光度法研究壳聚糖树脂吸附阴离子染料

利用流动注射分光光度法技术，跟踪观察交联壳聚糖树脂吸附阴离子染料的行为，讨论了外加氯化钠或甲醇以及温度等因素对吸附的影响。利用固－液相互作用方程，求取了吸附剂－吸附质相互作用能。实验结果表明，交联壳聚糖树脂吸附 子染料，其表观吸附速率常数随体系中氯化钠浓度或甲醇含量的增大而减小，随温度的升高而增大；交联壳聚糖树脂吸附酸性铬蓝K染料的表观活化能力26.095kJ/mol。     

DETERMINATION OF THERMODYNAMIC AND KINETIC PARAMETERS OF LARGE SCALE CHROMATOGRAPHIC SEPARATION OF SUGAR AND REDUCING SUGAR

ＤＥＴＥＲＭＩＮＡＴＩＯＮＯＦＴＨＥＲＭＯＤＹＮＡＭＩＣＡＮＤＫＩＮＥＴＩＣＰＡＲＡＭＥＴＥＲＳＯＦＬＡＲＧＥＳＣＡＬＥＣＨＲＯＭＡＴＯＧＲＡＰＨＩＣＳＥＰＡＲＡＴＩＯＮＯＦＳＵＧＡＲＡＮＤＲＥＤＵＣＩＮＧＳＵＧＡＲＬｉＺｈｏｎｇ；ＳｈｕＷｅｎｌｉ；...     

DETERMINATION OF THERMODYNAMIC AND KINETIC PARAMETERS OF LARGE SCALE CHROMATOGRAPHIC SEPARATION OF SUGAR AND REDUCING SUGAR

The parameter identification model of large scale chromatography separation process is proposed.The phase equilibrium constants and lumped mass transfer coefficients of sugar and reducing sugar adsorption on D1,D2 and D3 resins as well as the axial dispersion coefficients of the fluid through packed columns are determined by means of the pulse-response experiment technique with an inert substance as a tracer and the chromatography measuring technique.The elution curve calculated from these parameters is good agreement with the experimental elution curve.The sensitivity analysis of these parameters is carried out ,and the result shows that the elution curves of chromatography separation are more sensitive to the variations of the phase equilibrium relationship than to the variation of the axial dispersion as well as the lumped mass transfer coefficients.     

THE DETERMINATION OF ADSORPTION ISOTHERMS AND SOLID DIFFUSION COEFFICIENTS OF MANNITOL AND SORBITOL BY LIQUID CHROMATOGRAPHY TECHNIQUE

The parameter identification model is proposed for determining the linear adsorption isotherms and the solid diffusion coefficients by using adsorption chromatorgaphy.Axial dispersion coefficients is firstly determined by pulse-respond experiment technique with an inert substance as tracer,then the elution curves of chromatography separating the isomer mannitol and sorbitol are determined by the chromatographic measuring technique,and pinally the adsorption isotherms and the solid diffusion coefficients of mannitol and sorbitol on Ca^2+ resins are estimated by using this model.The results show that the axial dispersion coefficients increase with fluid velocity increasing,The adsorption equilibrium constants decrease with temperature rising;and the solid diffusion coefficients increase with temperature rising.The theoretical elution curves are good agreement with the experimental elution curves of the liquid adsorption chromatography separating the mannitol and the sorbitol.The model provides a simple and reliable procedure to estimate the kinetic and thermodynamic parmeters of the adsorption.     

SYSTEM IDENTIFICATION METHOD OF LINEAR AND NON-LINEAR LIQUID PREPARATIVECHROMATOGRAPHIC SEPARATION

1.INTRODUCTIONThechromatographicproblemistorelatetheconcentrationprofileofthebandattheoutletofthecolumntotheequilibriumisothelm,themasstransferkineticsandtheprofileoftheinjectionbandandperformtheoptimumdesignofseparationprocess['J.Togettheobjective,Itisnecessarytoidentifythesystemof.ProjectsupPOrtedbyTheNationalNaturalScienceFoundationofChinatheliquidadsorptionchromatographylinearornon-linear,andthendeterminethethermodynamicanddynamicsparametersofthesystemaccuratelysothatthecomputersim…     

特征线法在求解非线性液相吸附色谱模型中的应用

本文应用特征线法求解非线性液相吸附色谱分离过程模型，论述了特征线法的原理和步骤，讨论了时间步长和空间步长对模型数值解的影响，并用色谱分离甘露醇和山梨醇以及分离蔗糖和还原糖的实验进行验证，用特征线法计算的理论流出曲线与实验流出线吻合较好。本文还分折了模型中各个参数的灵敏度，结果表明：吸附等温方程Q＝Ci*／（ai＋biCi*）中参数ai比参数bi以及总传质系数ki有更高的灵敏度。     

Kinetic and equilibrium study of the enantioseparation of paroxetine intermediate on amylose and tartaric acid-based chiral stationary phases

trans-(-)-Paroxetine is a selective 5-hydroxytryptamine (5-HT) reuptake inhibitor currently used as an antidepressant. trans-(+/-)-3-Ethoxycarbonyl-4-(4'-fluorophenyl)-1-methylpiperidine-2,6-dione is an important intermediate of trans-(-)-paroxetine. It was separated on amylose and tartaric acid-based chiral stationary phases by HPLC. The equilibrium constants and overall mass transfer coefficients together with the axial dispersion coefficients were experimentally determined by moment analysis based on the lumped kinetic model of chromatography. In case of Kromasil CHI-TBB, the equilibrium constants measured were found to be 8.36 and 9.37 for trans-(+) and trans-(-) enantiomers, respectively. For Chiralpak AD-H, the equilibrium constants were 6.68 and 4.13 for trans-(+) and trans-(-) enantiomers, respectively. The axial dispersion coefficients of both enantiomers on Kromasil CHI-TBB column were about one order of magnitude greater than on Chiralpak AD-H. Fast kinetics of mass transfer in both chiral stationary phases was observed. Their overall mass transfer coefficients on Kromasil CHI-TBB and Chiralpak AD-H were 32.12, 33.18, 26.50, 46.85 s(-1) for trans-(+) and trans-(-) enantiomers, respectively. The parameters obtained were utilized to simulate the elution profiles, and the simulated and experimental results match well, which confirmed that the parameters obtained in this study were valid.     

Equilibrium and kinetic analysis of CO2-N2 adsorption separation by concentration pulse chromatography

CO2 and N(2) adsorption kinetics and equilibrium behaviours have been studied with silicalite, NaY and 13X by using concentration pulse chromatography for the separation of these gases in the present study. Adsorption Henry's Law constants, the heat of adsorption values, micropore diffusion coefficients and corresponding activation energies are determined experimentally and the three different mass transfer mechanisms are discussed. From the equilibrium data, the corresponding separation factors are obtained for the adsorption separation processes. The heat of adsorption values as well as the Henry's Law adsorption equilibrium constants of CO(2) are much higher than those of N(2) for all the adsorbents studied. 13X, NaY and silicalite all have good separation factors for CO(2)/N(2) system based on equilibrium processes. The order of the equilibrium separation factors is 13X (Ceca)>13X (Zeochem)>NaY (UOP)>silicalite (UOP). Equilibrium selectivity favours CO(2) over N(2). Micropore diffusion resistance is the definite dominant mass transfer mechanism for CO(2) with silicalite and NaY.     

Column selectivity from the perspective of the solvation parameter model

The solvation parameter model is a useful tool for delineating the contribution of defined intermolecular interactions to retention of neutral molecules in separation systems based on a solute equilibrium between a gas, liquid or fluid mobile phase and a liquid or solid stationary phase. The free energy for this process is decomposed into contributions for cavity formation and the set up of intermolecular interactions identified as dispersion, electron lone pair, dipole-type and hydrogen bonding. The relative contribution of these interactions is indicated by a series of system constants determined by the difference of the defined interaction in the two phases. The interpretation of these system constants as a function of experimental factors that affect retention in the chromatographic system provides the connection between relative retention (selectivity) and the control variables for the separation system. To aid in the understanding of these processes we perform an analysis of system constants for gas chromatography, liquid chromatography, supercritical fluid chromatography and micellar electrokinetic chromatography as a function of different experimental variables as a step towards gaining a theoretical understanding of selectivity optimization for method development.