碱性溶液萃取大黄蒽醌类产品动力学的研究

以大黄酸为代表,利用恒界面池法对碱性溶液萃取分离大黄蒽醌类产品的动力学进行了初步研究,以确定大黄中蒽醌类物质的萃取类型。研究结果表明,KHCO3水溶液萃取大黄酸的萃取动力学模式为化学反应控制模型。     

碱性溶液萃取大黄蒽醌类产品的平衡特性

选择碱性溶液5％的Na2CO3溶液为萃取剂,萃取大黄蒽醌类中的大黄素,考察温度和大黄素初浓度对萃取平衡分配系数的影响,同时分析碱性溶液5％的Na2CO3溶液在萃取前后的浓度变化量与分配系数的关系,从而可以了解碱性溶液萃取大黄葸醌类产品的一些平衡特性。     

异戊醇从氯化物-磷酸体系中萃取盐酸的动力学

采用上升液滴法研究异戊醇萃取盐酸的动力学,考察二相接触面积、水相中初始盐酸、磷酸浓度对盐酸萃取速率的影响,以比较磷酸和盐酸的萃取行为。实验结果表明,盐酸的初始正向萃取速率与二相界面积无关,随水相初始盐酸、磷酸浓度的增大而增大,异戊醇萃取盐酸可能属相内反应控制模式。水相中盐酸的存在促进磷酸的萃取,用较高浓度的工业盐酸分解开阳磷矿有利于湿法磷酸的分离和净化。经非线性最小二乘法回归实验数据,得出25℃时异戊醇萃取盐酸的动力学方程,其决定性指标为0.993 9,速率常数的相对标准偏差为7.69%。     

超临界二氧化碳流体萃取大黄蒽醌动力学模型

通过对萃取固定床层进行质量衡算建立了超临界CO₂流体萃取动力学模型.然后采用BP神经网络拟合实验条件下的萃取动力学曲线,并将之与动力学模型试差法求解所得的萃出曲线进行对照确定模型参数k_La.结果表明,BP神经网络能很好地模拟大黄蒽醌的萃取动力学曲线,网络训练误差和预测误差分别为1.5%和3.5%.确定参数后的动力学模型可用于对萃取床层作较为精确的定量描述：模拟所得萃取穿透曲线与大黄蒽醌萃取实验结果相比AARD误差在10%左右.与前人模型相比,该模型具有精度好,获取参数时的实验条件相对宽松等优点.     

氯化物-磷酸体系中异戊醇萃取磷酸的动力学研究

采用上升液滴法研究了氯化物-磷酸体系中异戊醇萃取磷酸的动力学,考察了两相接触面积和水相中磷酸、盐酸初始浓度对磷酸萃取速率的影响.结果表明:磷酸的初始正向萃取速率随着两相界面积和水相磷酸、盐酸初始浓度的增大而增大,异戊醇萃取磷酸可能属扩散控制模式,磷酸的初始正向萃取速率与水相中磷酸浓度呈准二级反应,与盐酸浓度呈一级反应.经线性最小二乘法回归实验数据,得出25℃时异戊醇萃取磷酸的动力学方程为Rp=4.719×10-8c1.802pc1.004Cl,其速率常数的计算值与实验值的相对标准偏差为5.02%.     

超临界CO2流体萃取大黄游离蒽醌的研究

研究了带夹带剂的超临界流体萃取大黄中的五种有效蒽醌类物质(大黄酚、大黄素、芦荟大黄素、大黄酸和大黄素甲醚)的工艺,考察了萃取条件(温度和压力)、CO2流量、萃取时间、夹带剂种类等对大黄游离蒽醌萃取率的影响.通过正交实验对萃取釜条件(萃取压力、温度和夹带剂用量)进行了优化;采用液相色谱对萃取产物进行了分析.结果表明,分离釜的温度和压力、CO2流量等对萃取效率影响较小;最佳工艺条件为静萃取时间为60 min、动萃取时间为30 min、以乙醇作夹带剂、乙醇用量300 mL·(100g大黄)-1、萃取温度45℃、萃取压力45 MPa.在此条件下大黄游离蒽醌的萃取量达1.15%.     

单液滴法研究溶剂萃取动力学进展

萃取广泛应用于化工及冶金行业的分离过程中,而萃取过程的动力学是进行萃取单元设备设计及选型的重要依据之一。对萃取动力学的研究方法主要有恒界面池法、两相充分混合法、界面积短时间相接触法和单液滴法,而单液滴法因具有装置简单、操作方便、测量数据准确等优点而得到广泛应用。本文综述了单液滴法用于萃取动力学研究的设备、方法、原理及数据处理方法,展望了单液滴技术在萃取动力学研究中应用的前景。     

β-萘酚稀溶液萃取动力学研究

选用磷酸三丁酯 甲苯混合溶剂对β 萘酚稀溶液进行萃取动力学研究,考察了搅拌强度、二相界面积、水相β 萘酚质量浓度、水相pH值、有机相内萃取剂体积分数和温度对萃取速率的影响。实验结果表明,磷酸三丁酯萃取β 萘酚的动力学模式为化学反应控制模式,且为水相内反应控制类型。根据实验结果建立了磷酸三丁酯萃取β 萘酚的动力学模型。     

乙二醛溶液体系中乙酸络合萃取的动力学研究

采用恒界面池法研究了乙酸在乙二醛溶液中的萃取动力学,实验结果表明：萃取速率由界面化学反应所控制,且表观反应速率方程为：ｒ＝ｋｓＣＨＡｃ１．３６４１,在２５℃时的反应速率常数ｋｓ＝１．８２×１０－２ｍｏｌ／ｃｍ２·ｓ。此外,还研究了温度对反应速率的影响,求取了表观反应的活化能Ｅａ＝２３．２８３３ｋＪ／ｍｏｌ,从而进一步说明了萃取速率控制步骤为界面化学反应所控制。     

蒽醌法生产过氧化氢中萃取过程的模拟

利用PRO/Ⅱ7.1过程模拟软件模拟了蒽醌法制双氧水工艺的萃取过程,得出了100 kt/a的萃取塔的操作工艺参数以及运行结果,分析了塔板数,萃取剂用量,温度等操作条件对萃取结果的影响,并与某化学厂的双氧水萃取塔进行了比较。证实了模拟所得工艺参数的优越性,并且对改进萃取塔,扩大双氧水的生产提供了一些参考。     

Mathematical Modeling of Two-Stage Extraction Kinetics using the Single Drop Technique

This paper focuses on the mathematical modeling of the two-stage extraction using the single drop technique. Two stages of extraction are being considered: the drop formation step, where dimensions of the drop are highly dependent on time, and the drop travel step, during which the drops size and dimensions are assumed constant. Models for both extraction steps are derived and the combined model is proposed. Two-stage and one-stage models of extraction are compared. Errors occuring when considering only the travel stage of the single drop extraction have been calculated and their dependencies on various extraction parameters have been determined. The analysis of the combined two-stage model has proven that the travel-stage-only model generates significant errors during the determination of reaction rate constants when the drop formation time is significant in relation to the whole extraction time. Thus, the two-stage model should be used to reduce originating errors.     

纤维素酶法提取黄芪多糖的动力学

采用纤维素酶辅助提取(CAE)黄芪多糖(APS),探讨了温度和粒径等对提取动力学特征的影响,采用扫描电镜观察了CAE和水提(AE)后样品的表面细胞结构. 结果表明,黄芪多糖的提取符合Fick第二定律,纤维素酶不改变提取传质动力学,仅破坏细胞壁,降低扩散阻力,使黄芪多糖的传质速率和有效扩散系数D￠明显提高. 实验得到D￠与温度T和APS粒径R0的关系,水提时为lnD￠=-9.30-926.7/T+1.76lnR0,酶提时为lnD￠=-10.56-491.4/T+1.75lnR0.     

Extraction of copper from dilute solutions by LIX 64N. Effect of dekalin and tetralin as diluents on the equilibrium and rate of mass transfer

Liquid-liquid equilibrium data and mass transfer rates for the extraction of copper from dilute aqueous sulphate solutions by LIX 64N with dekalin (decahydronaphthalene) and tetralin (1,2,3,4-tetrahydronaphthalene) as diluents are reported. The stripping of copper from the organic phase was also studied. For an initial copper concentration of 1.5 g dm^?3 extraction efficiency decreases as the concentration of tetralin increases in the diluent mixtures of dekalin-tetralin. This behaviour is explained as a result of the formation of oxime aggregates and the interaction between the oxime and the diluent. Initial rates of extraction and stripping were determined by the single drop technique. The linear relation between initial rates of extraction and the difference of interfacial tension between the extractant in the diluent and the diluent itself holds for the system under investigation.     

三烷基胺萃取丙酸的动力学特性

为研究胺类萃取剂萃取有机酸的动力学行为 ,以丙酸稀溶液为分离溶质 ,三烷基胺 ( 730 1)为萃取剂 ,正辛醇和煤油的混合物为稀释剂 ,采用恒界面池法考察了萃取剂和溶质浓度、搅拌速率、两相接触面积、温度等操作参数对丙酸萃取动力学的影响。结果表明 :730 1萃取丙酸为准一级反应萃取过程 ;且萃取发生在相界面 ,即界面反应萃取机制 ;表观活化能为 2 8.5kJ/mol,萃取速率受温度的影响不显著 ;经计算 ,在一般的萃取塔操作条件下 ,该体系的萃取过程为反应和传质过程的混合控制。     

Kinetics of Forward Extraction of Boric Acid from Salt Lake Brine by 2-Ethyl-1,3-hexanediol in Toluene Using Single Drop Technique

The kinetics of forward extraction of boric acid from salt lake brine by 2-ethyl-1,3-hexanediol in tolu-ene was investigated using the single drop technique. The factors affecting the extraction rate include interfacial area between aqueous phase and organic phase, initial concentration of boric acid in aqueous phase, initial concen-tration of 2-ethyl-1,3-hexanediol in organic phase, and extraction temperature. The experimental results show that the extraction rate increases with the increase of the initial concentration of boric acid and 2-ethyl-1,3-hexanediol, interfacial area of two phases, and temperature. With the temperature-dependence study, it is showed that the ex-traction is a diffusion-controlled process. The kinetic equation is presented for pH 1.0 in the aqueous phase and temperature of 318 K.     

Kinetics of Ultrasound-Assisted Polyphenol Extraction from Spent Filter Coffee Using Aqueous Glycerol

Culinary filter coffee residues were utilized as raw material, with the aim of recovering functional polyphenolic components. The extraction was performed under ultrasonication using aqueous glycerol, and for this reason, the process was initially optimized with regard to glycerol concentration (C_gl) and extraction time (t), by implementing response surface methodology via a central composite (Box-Behnken) experimental design. The optimized conditions determined were C_gl = 3.6% (w/v) and t = 175 min. The comparative assessment, based on a kinetic assay, illustrated that the progression of the extraction was slower in aqueous glycerol than in water, yet aqueous glycerol was proven a more efficient extraction medium, providing 7.4% higher total polyphenol yield. Liquid chromatography-diode array-mass spectrometry analysis revealed that the major antioxidant phytochemicals in the aqueous glycerol extract were chlorogenic acids (caffeic acid derivatives), accompanied by some other polyphenolic metabolites.     

水葫芦生物降解动力学实验研究

以富含纤维素的水葫芦粉末为发酵底物,经驯化的厌氧污泥为接种物,在中温条件下(34℃)进行了探索性实验。计算了序批式厌氧发酵过程的主要生物动力学参数。给出了发酵过程的比基质利用常数K=0.058d-1和基于底物投料量P(以VSS计,g/L)与接种污泥量X(以MLVSS计,g/L)的水解速率方程r=1.40P+20.07X-53.74。实验中测定所产生物气中最高甲烷含量为59%。     

十六烷基溴化吡啶水溶液的动态吸附量研究

滴体积法测定了十六烷基溴化吡啶(CPB)水溶液的动态表面张力。不同浓度的溶液遵从不同的动态表面状态方程,浓度低于0.031 mol·m~(-3)时,动态吸附量T_1遵从由Henry吸附等温式导出的动态表面状态方程;浓度位于0.031～0.560mol·m~(-3)的较大范围内,T_1遵从由Langmuir和Freundlich等温式导出的动态表面状态方程;在更高的浓度下(如0.683 mol·m~(-3)),T_1只遵从从Langmuir等温式得出的表面状态方程。