响应面优化葛根黄酮提取工艺研究

验以葛根粉为原料、乙醇为溶剂,研究了不同提取时间、不同提取温度、不同乙醇浓度对葛根黄酮提取率的影响,在单因素实验的基础上用紫外分光光度计法进行含量测定,并进行了3因素3水平的Box-Behnken设计优化了葛根黄酮的有关提取参数,最优工艺条件为:提取时间60min、提取温度80℃、乙醇浓度60%。在最佳优化条件下葛根黄酮提取率达到极大值,葛根黄酮提取率为36.64%。该方法快速简单,结果准确,可用于葛根素提取。     

葛根中黄酮的提取与纯化研究

以葛根粉为原料,采用乙醇提取法,研究葛根中黄酮的提取及纯化工艺。采用紫外分光光度法测定黄酮标准曲线用于计算葛根中黄酮含量。在乙醇提取法提取葛根黄酮的研究中,以提取时间、料液比、乙醇体积分率、温度为考察因素,进行单因素条件研究。结果表明,最佳提取时间为1.5 h,料液比为1∶13 g/m L,乙醇体积分率为40%,温度为60℃,葛根黄酮的提取率达到2.64 mg/g。以LS-303型大孔吸附树脂为吸附剂,以葛根黄酮在该树脂上的最佳动态吸附与解吸条件为操作参数,采用树脂柱进行葛根提取液中黄酮的分离纯化,采用紫外分光光度法检验纯化效果,研究发现LS-303型树脂对葛根黄酮有良好的纯化作用。     

从银杏叶中提取银杏黄酮的研究

采用水-乙醇作提取溶剂回流提取了银杏叶中的银杏黄酮.设计正交实验确定影响提取银杏黄酮的显著因素为料液比、乙醇浓度、提取温度.单因素实验确定提取工艺的最佳条件为料液比110,乙醇浓度70%,提取温度70℃,粒度40～80目,回流提取时间为2h.银杏黄酮的提取率达到86.5%.     

从银杏叶中提取银杏黄酮的研究

采用水-乙醇作提取溶剂回流提取了银杏叶中的银杏黄酮.设计正交实验确定影响提取银杏黄酮的显著因素为料液比、乙醇浓度、提取温度.单因素实验确定提取工艺的最佳条件为料液比1:10,乙醇浓度70%,提取温度70℃,粒度40～80目,回流提取时间为2h.银杏黄酮的提取率达到86.5%.     

大别山区葛根黄酮的微波辅助提取工艺研究

采用微波辅助提取法,研究了提取剂体积分数、提取时间、微波功率、料液比等工艺条件对大别山区葛根黄酮提取率的影响,并采用薄层色谱法对黄酮类成分进行定性分析,再利用紫外分光光度法对其定性和定量分析。结果表明:葛根黄酮提取的最佳工艺为:乙醇体积分数60%,提取时间4 min,微波功率340 W,物料比1∶50;其黄酮类化合物的母核结构多为异黄酮、二氢黄酮及二氢黄酮醇类。     

飞天蜈蚣七中黄酮提取的动力学

根据天然植物中活性成分提取机理和扩散理论,对飞天蜈蚣七中黄酮提取的动力学进行研究。首先在不同提取温度、提取时间下测定提取液中黄酮的浓度,发现随着提取温度的升高、提取时间的增长,黄酮浓度不断增加并最终趋于平衡;然后以Fick第二定律、球形模型为基础建立提取过程中的动力学模型并求得了速率常数、活化能、内扩散系数、相对萃余率等动力学参数。建立的动力学模型可为飞天蜈蚣七黄酮提取的工艺条件优化和深层次研究奠定理论基础。     

花生壳黄酮乙醇提取工艺探讨

研究了乙醇浸提工艺对花生壳总黄酮提取的影响.采用单因素实验和正交实验研究了不同工艺条件对花生壳黄酮提取效率的影响,并采用超声波辅助提取,确定了最佳浸提工艺及相关工艺参数.结果表明,最佳提取条件为:乙醇质量分数65%,料液比1∶40,pH 7.0,超声波频率40 kHz,超声波作用时间15 min,提取温度75℃,提取时间1.5 h,此时花生壳黄酮的提取量可达9.42 mg/g.     

金莲花黄酮超声波提取的动力学模型

以金莲花中黄酮提取量为考察指标,研究以体积分数50%的乙醇溶液为提取剂,超声波辅助提取金莲花总黄酮的传质动力学过程。根据质量平衡方程,利用实验测得的提取过程中的重要动力学和热力学参数,建立了金莲花黄酮超声波提取的动力学模型。结果表明:金莲花黄酮超声波提取过程为准一级反应,所建立的动力学模型能较好地描述金莲花黄酮的超声波提取过程。     

葛根黄酮分散片的制备

探讨葛根黄酮分散片的制备工艺.考察了羧微晶纤维素(MCC)、低取代羟丙基纤维(L-HPC)、交联聚乙烯吡咯烷酮(PPVP)、微粉硅胶等对葛根黄酮分散片崩解时限的影响,对最佳处方进行了溶出度测定及方法学考察.     

纤维素酶法提取竹叶黄酮的传质动力学

采用纤维素酶法提取竹叶中的总黄酮类化合物,讨论了温度、原料尺寸、转速及纤维素酶用量对传质速率的影响,并用扫描电镜观察了水提和酶提取后样品的细胞结构变化。结果表明,竹叶黄酮的提取动力学符合平板型Fick第二定律,提取过程主要受内扩散控制;纤维素酶不改变传质动力学机理,它只破坏细胞壁,从而降低扩散阻力使溶质的传质速率和表观扩散系数D′提高。实验还得到了D′与提取温度、竹叶几何尺寸之间的关系,在30～60℃,酶提时的D′为1.95×10 13～6.85×10 13m2·s-1,水提时的D′为1.73×10 13～6.05×10 13m2·s-1;酶提时的活化能Ea为11.853kJ·mol-1,比水提时降低了9.59%。该研究为酶法提取竹叶黄酮的工艺设计及工业化应用提供了理论依据。     

葡萄糖高温降解生产乙酰丙酸的动力学研究

Levulinic acid is a kind of new green platform chemical with wide application. The kinetics of levulinic acid formation from glucose decomposition at high temperature was investigated. Glucose containing 1%, 3% or 5% H2SO4 was treated at 170℃ or 190℃. For the various experimental conditions assayed, the time-courses of glucose and glucose degradation products （including 5-hydroxymethylfurfural and levulinic acid） were established. These variables were correlated with the reaction time based on the equations derived from a pseudo-homogeneous, first-order kinetic model, which provided a satisfactory interpretation of the experimental results. The set of kinetic parameters from regression of experimental data provided useful information for understanding the levulinic acid formation mechanism.     

聚醚与含氢硅油的硅氢加成反应的动力学研究

The hydrosilylation of polyhydrosiloxane and unsaturated allylic polyether terminated with ester group is processed with chloroplatinic acid as catalyst and ethyl acetate as solvent to exclude the mass transfer resistance in the system. The kinetic study is performed by means of Gel Permeation Chromatography. Within the experimental range （mass ratio of the whole reactants to solvent is 1：4, the tool ratio of Si-H bond to carbon-carbon double bond is 1： 1.3, the catalyst concentration from 1.0×10^-4mol·L^-1 （Pt） to 3.1×10^-4mol·L^-1 （Pt）, temperature between 338.15K and 350.35K）, a kinetic model of zero-th order reaction is built up and the evaluated model parameters are found to change linearly with the catalyst concentration.     

钛硅分子筛催化环已酮氨肟化反应动力学

An intrinsic kinetics of cyclohexanone ammoximation in the liquid phase over titanium silicate molecular sieves is investigated in an isothermal slurry reactor at different initial reactant concentrations, catalyst loading,and reaction temperature. The rate equations are developed by analyzing data of kinetic measurements. More than 10 side reactions were found. H202 decomposition reaction Inust be considered and other side reactions can be neglected in the kinetic modeling. The predicted values of reaction rates based on the kinetic models are almost consistent with experimental ones. The models have guidance to the selection of reactor types and they are useful to the design and operation of reactor used.     

超临界流体萃取脱除人参中痕量有机氯农药

The feasibility of removal of the organochlorine pesticides residues of hexachlorocyclohexane(BHC) from radix ginseng with supercritical CO2 was explored. Some factors, such as extraction pressure, extraction temperature, and kinds of co-solvents were investigated. The experimental results indicate that it is possible to reduce BHC residues in radix ginseng to the level of 0.1×10-6 with supercritical CO2 in the presence of suitable amount of co-solvent, such as water.     

微波协同萃取射干异黄酮的研究

Microwave-assisted extraction （MAE） of isoflavones from Belamcanda chinensis was studied using ethanol as the solvent. The single factor experiment and the orthogonal method were used to optimize the MAE condition. It was concluded that two doses of intermittent microwave power radiation, 300 W each for 4 rain, were needed for extraction. The mass ratio of solvent to material was 8：1 and the alcohol mass fraction was 80%. The extracted liquor was then concentrated under vacuum and degreased with petroleum ether. The yield of total isofiavones was about 8.8% and the contents of tectoridin and iridin were 67.6% and 16.3% respectively. Compared with direct-heating extraction （DHE）, MAE may shorten extracting duration, reduce solvent consumption, and improve yield and purity of isoflavones from Belamcanda chinensis.     

二苯并呋喃在活性炭上的吸附相平衡和动力学

The adsorption of dibenzofuran on three commercial granular activated carbons （ACs） was investigated by dynamic experiment to correlate the adsorption equilibrium and kinetics with the structure of activated carbons. Physical properties including surface area, average pore diameter, micropore area and micropore volume of the activated carbons were characterized by N2 adsorption experiment on ASAP2010. To calculate the adsorption parameters, adsorption isotherm data were fitted to the Langmuir equation, and adsorption kinetic data were fitted to the linear driving force （LDF） diffusion model. From the correlation results, it is concluded that the adsorption equilibrium and diffusion coefficient of dibenzofuran on activated carbon are controlled respectively by the total adsorbent surface area and the adsorbent pore diameter.     

用对应态基团贡献法估算有机物偏心因子

A new estimation method was proposed by combining the corresponding state principle with the group contribution method through introducing the concept of assumed-critical properties. Combining it with the Reidel equation, a new acentric factor correlation equation （CSGC-Reidel） was developed. Contribution values of 70 groups were obtained by correlating acentric factor data of 228 organic compounds of 14 type substances including saturated hydrocarbons, unsaturated hydrocarbons, cyclanes, aromatics, oxygen compounds, nitrogen compounds, halohydrocarbons, etc. The average error of acentric factor is 3.52% between the literature data and the predicated with the new estimation method.     

超声内环流气升式反应器中环己烯环氧化反应的研究

Epoxidation of cyclohexene to cyclohexene oxide was studied in a new type reactor-the ultrasound airlift loop reactor. The influences of ultrasound intensity, molar ratio of isobutyraldehyde to cyclohexene and oxygen gas flow rate on the conversion of cyclohexene and selectivity of cyclohexene oxide were investigated and discussed, and the optimal operation condition was found, under which 95.2% conversion of cyclohexene and 90.7% selectivity of cyclohexene oxide were achieved. The ultrasonic airlift loop reactor utilizes the synergistic effect of sonochemsitry and higher oxygen transfer rate. Possible reaction mechanisms were outlined and the reason of ultrasound promotion of epoxidation reactionwas analyzed.     

利用最大泡压法研究扩散控制的溶液表面吸附动力学

In studying the diffusion-controlled adsorption kinetics of aqueous surfactant solutions at the air/solution surface by means of the maximal bubble pressure method, Fick's diffusion equation for a sphere should be used. In this paper the equation was solved by means of Laplace transformation under different initial and boundary conditions. The dynamic surface adsorption (t) for a surfactant solution, which was used to describe the diffusion-controlled adsorption kinetics at the solution surface, was derived. Different from the planar surface adsorption, the dynamic surface adsorption (t) for the short time consists of two terms: one is the same as WardTordai equation and the other reflects the geometric effect caused by the spherical bubble surface. This effect should not be neglected for the very small radius of the capillary. The equilibrium surface tension γeq and the dynamic surface tension γ(t) of aqueous C10E6 [CH3(CH2)9(OCH2CH2)6OH] solution at temperature 25°C were measured by means of Wilhelmy plate method and maximal bubble pressure method respectively. As t → 0, the theoretical analysis is in good agreement with experimental results and the dependence ofγ(t)on(√t r0/√πD)2 is linear.