天然植物油碱异构化合成共轭亚油酸的研究

以天然植物油为原料 ,碱异构化合成CLA。研究了反应时间、反应温度、溶剂用量、天然植物油用量等因素对CLA转化率的影响。试验结果表明 ,最适宜的异构化条件为 :反应时间为 2 5～ 3h ,反应温度为 16 0～ 170℃ ,溶剂用量为碱用量的 2 5～ 3 5倍 ,天然植物油用量为碱用量的 1～2倍 ;适宜条件时CLA转化率达 80 %以上。该方法比较简单 ,产物容易处理 ,且有机溶剂丙二醇无毒性 ,较适合用于CLA的功能食品和保健品的开发。

橡胶籽油碱异构制备共轭亚油酸的研究

以橡胶籽油为原料,KOH为催化剂,碱异构化合成CLA。采用单因素和正交实验研究了反应温度、反应时间、不同溶剂、加碱量等因素对CLA转化率的影响。得到橡胶籽油碱异构制备共轭亚油酸的最佳异构条件是:反应温度140℃,反应时间1.5h,加碱量与橡胶籽油皂化值的比值是1.2。在此实验条件下,CLA纯度达到29.1%,转化率为85.67%。

橡胶籽油碱催化异构化合成共轭亚油酸的制备工艺研究

以橡胶籽油为原料,碱异构化合成共轭亚油酸(CLA),采用单因素实验探讨了反应温度、反应时间、醇油比、催化剂KOH的用量等因素对CLA转化率的影响,同时采用响应曲面法进行优化,结果表明:橡胶籽油碱异构制备共轭亚油酸的最佳异构条件是:采用聚乙二醇-400为溶剂,KOH为催化剂,当反应温度148℃,反应时间2.6 h,醇油比:18∶1 m L/g,催化剂的用量6%,在此工艺条件下橡胶籽油共轭亚油酸的转化率为83.04%。

烟籽油碱催化异构化制备共轭亚油酸技术研究

[目的]研究烟籽油制备共轭亚油酸(CLA)的工艺条件。[方法]以烟草种子榨制的烟籽油为原料,丙二醇为溶剂,氢氧化钾为催化剂,采用碱催化异构化合成CLA,探索反应温度、反应时间、催化剂用量对CLA转化率的影响,并采用响应面法优化最佳条件。[结果]3个因素对转化率的影响程度表现为催化剂用量>反应温度>反应时间;在丙二醇20 mL,烟籽油5 g的反应体系下,优化后反应温度为171.18℃,反应时间为5.22 h,碱用量3.43 g,CLA转化率最高,预测转化率为93.32%,实际转化率为(92.78±0.74)%。[结论]该研究可为烟籽油作为原料制备CLA提供科学依据。

钩藤碱和异钩藤碱对豚鼠心房的负性变时和变力作用

钩藤碱(Rhy)及异钩藤碱(Isorhy)呈剂量依赖性减慢右心房自发节律,且不被Atr阻断,二药非竞争性地拮抗Iso和组胺正性变时作用,其pD_2值分别为Iso 5.45和5.57,H 5.28和5.48,并能取消CaCl_2的正性变时效应,Rhy和Isorhy还剂量依赖性地抑制心房收缩力,在1μmol·L^(-1)普萘洛尔存在下,二药对苯肾上腺素正性变力作用的量效曲线是非竞争性拮抗,其pD_2值分别为43.6和4.43.Rhy和Isorhy 0、3mmol·L^(-1)能显著抑制左心房静息后增强效应和阶梯现象.结果提示,Rhy和Isorhy的负性变时和变力作用,似与二药抑制心肌细胞膜Ca^(2+)转运有关。

HPLC法测定不同产地钩藤中异钩藤碱和钩藤碱的含量

目的:建立高效液相色谱测定不同产地的钩藤中异钩藤碱和钩藤碱的方法。方法:采用Diamonsil-C18色谱柱,流动相为甲醇:0.2%氨水(65∶35),检测波长245nm。结果:线性范围0.08805-0.8805μg和0.04076-0.4076μg,相关系数为0.9996和0.9997,平均回收率异钩藤碱为97.03%,钩藤碱为98.95%,RSD分别为1.79%和2.55%。结论:高效液相色谱法可为钩藤质量控制标准的制定提供相应的依据。

钩藤总碱中钩藤碱和异钩藤碱定量方法的建立及稳定性试验

目的建立钩藤总碱中钩藤碱和异构藤碱的含量测定方法并对其稳定性进行研究。方法采用C18柱(4.6 mm×150 mm,5μm),甲醇∶0.1 mol/L三乙胺溶液(冰醋酸调pH 7.5)44∶56为流动相,流速为1.0 ml/min。检测波长254 nm。比较分别放置在室温、6℃条件下的同一批次2份总碱中钩藤碱、异构藤碱的含量变化。结果钩藤碱进样量在0.020 2～0.101 mg/ml线性关系良好,r=0.999 9;异构藤碱进样量在0.020 6～0.103 mg/ml线性关系良好,r=0.999 9,钩藤碱平均回收率为99.67%,RSD为0.97%;异钩藤碱平均回收率为99.95%,RSD为1.02%。结论建立的方法简便、准确,可作为钩藤总碱的含量测定方法;钩藤碱、异构藤碱不稳定,可随时间延长含量下降,且温度对二者皆有影响,对钩藤碱影响较大。

高纯度共轭亚油酸的制备

以红花籽油为原料,比较了2种高纯度共轭亚油酸(CLA)的制备方法:(1)碱法异构化-尿素包合、(2)皂化-尿素包合-碱法异构化。针对每种方法确定了尿素包合和碱法异构化的最佳工艺条件,并对所得的CLA异构体组成进行了分析。研究表明:按照方法(2)先获得高纯度亚油酸(LA),再对其碱法异构化制备CLA可以得到纯度更高的产品。该方法在最佳反应条件下,制备得到的CLA的纯度为97.22%,收率为32.08%,其中c9t11-CLA含量为45.14%,t10c12-CLA含量为49.12%。

Potencies of Four Stereoisomers of Anisodamine on Muscarinic Receptor

用[3~H]-QNB配体受体结合实验,抗Ach对豚鼠回肠纵肌条收缩效应,抗毛果芸香碱流涎及扩瞳效应为指标,比较山莨菪碱四个立体异构体(A.6S,2′S;B.6S,2′R;C.6R,2′R;D.6R,2′S)与M受体相互作用的构效关系,结果A,B,C,D四个异构体效应分别为:(1)受体结合实验K_i(M)2.69×10^(-7),1.43×10^(-7),1.63×10^(-5),2.15×10^(-6);(2)抗Ach豚鼠回肠纵条收缩:K_6(M)2.98×10^(-8);1.38×10^(-8);1.52×10~5;1.0l×10^(-7);(3)扩瞳:ED_4(mol/kg)1.6×10^(-6),1.9×10^(-6),5.1×10^(-5),3.6×10^(-5);(4)抗毛果芸香碱流涎:ED_(50)(mol/kg)1.5×10^(-6);1.3×10^(-6);2.6×10^(-5);3.1×10^(-5)。以上结果表明四个异构体效应强度为6S,2′R≌6S,2′S>>6R,2′S>6R,2′R。

Theoretical Studies on Dihedral Angle-Bending Isomers of M2Pt2^0/- Clusters

The structures and electronic properties of the gaseous M2Pt20/-clusters(M represents the alkaline earth metal)were investigated using the density functional theory(B3LYP and PBE0)and wave function theory(SCS-MP2,CCSD and CCSD(T)).The results indicate that the D2 hisomers with the planar structures are more stable than the C2v isomers with smaller dihedral angles and shorter Pt-Pt bond lengths.The mutual competition of M(s,p)-Pt(5d)interaction and Pt-Pt covalent bonding contributes to the different stabilizations of the two kinds of isomers.The M(s,p)-Pt(5d)interaction favors the planar isomers with D2 hsymmetry,while the Pt-Pt covalent bonding leads to the C2 visomers with bending structures.Two different crossing points are determined in the potential energy curves of Be2Pt2 with the singlet and triplet states.But there is just one crossing point in potential energy curves of Ra2Pt2 and Ca2Pt2-because of flatter potential energy curves of Ra2Pt2 with the triplet state or Ca2Pt2-with quartet state.The results reveal a unique example of dihedral angle-bending isomers with the smallest number of atoms and may help the understanding of the bonding properties of other potential angle-bending isomers.

Apparent Dissolution Kinetics of Diatomite in Alkaline Solution

The dissolution kinetics of diatomite in alkaline solution is the theoretical basis for the process optimization of alkali-diatomite reaction and its applications.In this study,the dissolution kinetics of diatomite in NaOH solution is investigated.The results indicate that the dissolution reaction fits well the unreacted shrinking core model for solid-liquid heterogeneous reactions.The apparent reaction order for NaOH is 2 and the apparent activation energy for the reaction(Ea) is 28.06 kJ·mol-1.The intra-particle diffusion through the sodium silicate layer is the rate-controlling step.When the dissolution reaction occurs at the interface of unreacted diatomite solid core,the diffusion in the trans-layer(the liquid film around the wetted particle) reduces the rate of whole dissolution process.

Characterization of subtype selection properties of R-(-)-DM-phencynonate hydrochloride and its racemate on muscarinic receptors

In order to compare the potential selectivity of R-（-）-DM-phencynonate hydrochloride with its racemate （±）-DM- phencynonate hydrochloride on acetylcholine muscarinic receptor subtypes, the five human acetylcholine muscarinic receptor subtypes （M1- M5） （CHO-hml-5R） were cloned and expressed in Chinese hamster ovary （CHO-K1） cell line. The specific mRNAs of the five acetylcholine muscarinic receptor subtypes were detected by the reverse transcription-polymerase chain reaction （RT-PCR） method, demonstrating the definite expression of muscarinic receptor subtype genes （CHO-hml-5R）. The affinity and saturability of different muscarinic receptor subtypes to [^3H] N-methylscopolamine （[^3H]-NMS） were obtained by radioligand binding assay. Equilibrium binding assay revealed that the maximum binding capacity of [^3H]-NMS （Bmax value） to CHO-hml-5R were 40.22±3.23, 24.53±4.11, 29.65±2.65, 25.41±2.46, 32.78±4.81 pmol/mg·protein, respectively. Kd values of [^3H]-NMS to muscarinic receptors M1 to M5 were 0.97±0.22, 1.16±0.14, 0.99±0.06, 0.56±0.08, 1.12±0.06 nM, respectively. R-（-）-DM- phencynonate hydrochloride was found to block the M4 receptor with a much higher potency （pD2 = 7.48） than those displayed on M1 （pD2 = 6.20）, M2 （pD2 = 5.99）, M3 （pD2 = 5.99） and M5 （pD2 = 6.70） subtypes. However, for （±）-DM-phencynonate hydrochloride, no significant subtype receptor selectivity was found. Both （±）-DM- and R-（-）-DM-phencynonate hydrochloride showed allosteric effects on muscarinic receptors, the Hill coefficient （nH） of five receptor subtypes was less than 1, respectively. The results revealed that R-（-）-DM-phencynonate hydrochloride showed selectivity torwards M4 subtype, and there were allosteric effects for both R-（-）-DM-phencynonate hydrochloride and （±）-DM-phencynonate hydrochloride on muscarinic receptors.

Heterogeneous degradation of toxic organic pollutants by hydrophobic copper Schiff-base complex under visible irradiation

A hydrophobic complex of Cu2＋[bis-salicylic aldehyde-o-phenylenediamine], Cu-SPA, was prepared and used as a heterogeneous photocatalyst to degrade organic pollutants in water under visible irradiation （λ≥420 nm） at neutral pH. The structure of complex was characterized by using nuclear magnetic resonance （NMR）, elemental analysis, IR and UV-vis spectrometries. Degradation of Rhodamine B （RhB）, Sulforhodamine B （SRB） and Benzoic acid （BA） in water were used as model reactions to evaluate the photocatalytic activities of Cu-SPA. The results indicated that RhB and SRB were easily adsorbed on the hydrophobic surface of Cu-SPA from aqueous solution （the maximum adsorption amount： Qmax = 11.09 and 8.05 μmol/g, respectively）. Under visible irradiation, RhB and SRB were decolorized completely after 210 and 240 min, respectively, and BA was removed completely after 5 h. The efficiency of H202 was 〉 95%, in contrast to that of the reaction without catalyst or light （〈 20%）. In water soluble medium, the hydrophobic Cu-SPA can be used more than 6 cycles. ESR results and the behavior of cy- clic voltammetry showed that, in the reaction process, Cu2＋-SPA was reduced to intermediate state Cu＋-SPA firstly, which was extremely unstable and reacted rapidly with H2O2, leading to high reactive oxygen species （.OH radical ） to degrade the substrate.

Temperature-controlled synthesis of heterostructured Ru-Ru_(2)P nanoparticles embedded in carbon nanofibers for highly efficient hydrogen production

Developing highly efficient,cost-effective,and stable electrocatalysts for hydrogen evolution reaction(HER)is of considerable importance but remains challenging.Herein,we report the fabrication of a robust Ru-based electrocatalyst,which comprises heterostructured Ru-Ru_(2)P nanoparticles that are embedded in the N,P-codoped carbon nanofibers(CNFs),through a synthetic strategy involving electrospinning and temperature-controlled pyrolysis treatment.The as-prepared Ru-Ru_(2)P catalyst(Ru-Ru_(2)P@CNFs)shows excellent HER catalytic activities with low overpotentials of 11 and 14 mV in acidic and alkaline media,respectively,to achieve a current density of 10 mA cm^(−2),which are superior to the individual components of pure Ru and Ru_(2)P catalysts.Density functional theory calculations demonstrate the existence of electronic coupling effect between Ru and Ru_(2)P at the heterointerfaces,leading to a well-modulated electronic structure with optimized hydrogen adsorption strength and enhanced electrical conductivity for efficient HER electrocatalysis.In addition,the overall synthetic strategy can be generalized for the synthesis of a series of transitional metal phosphide-based nanofibers,thereby holding a remarkable capacity for various potential applications.