Kinetic study on reactive extraction of phenylalanine enantiomers with BINAP-copper complexes

Enantioselective liquid–liquid extraction has attracted considerable attention for its potential use in large-scale production. Kinetic data are needed for the reliable scale-up of the process. This paper reports the kinetic study of reactive extraction of phenylalanine (Phe) enantiomers with BINAP–copper complex (BINAP–Cu) as a chiral selector. The theory of extraction accompanied by a chemical reaction was applied. The effects of agitation speed, interfacial area, pH value of aqueous phase, initial concentration of Phe enan-tiomers and initial concentration of BINAP–Cu on the specific rate of extraction were investigated. The for-ward rate constants of the reactions in the reactive extraction process are 7.93 × 10?5 m5/2·mol?1/2·s?1 for D-Phe and 1.29 × 10?4 m5/2·mol?1/2·s?1 for L-Phe.     

橘黄酮的提取及其抑菌特性

采用乙醇浸提法从橘子皮中提取黄酮,通过正交试验确定提取的最佳条件为：70%乙醇为提取剂,固液比为1︰20(g/mL),提取温度是70℃,提取时间2h,在510nm处测定橘黄酮质量浓度为0.205g/L,从橘子皮中提取的黄酮干重得率为2.938mg/g。本实验探究橘黄酮的抑菌活性,采用牛津杯法测抑菌作用,结果表明,橘黄酮对金黄色葡萄球菌、大肠杆菌、黑曲霉、灰葡萄孢菌和黄枝孢菌均有抑制作用,铜和镁离子可分别增强橘黄酮对细菌和真菌的抑菌作用,低pH和低温可提高抑菌效果,且优化pH和温度的橘黄酮剂型降低了最小抑菌浓度（MIC）20%,对金黄色葡萄球菌、大肠杆菌、黑曲霉、灰葡萄孢菌和黄枝孢菌的抑菌作用分别提高了17%、27%、25%、28%、19%,高于对氯间二甲苯酚和甲基托布津的抑菌作用,特别是高于对细菌的抑菌作用。     

油茶叶多糖的闪式提取工艺优化及其抗氧化活性

在单因素试验基础上用响应面法对油茶叶多糖的闪式提取工艺进行优化,并对较优条件下提取的多糖的抗氧化活性进行测试.研究结果表明:油茶叶多糖闪式提取的较佳工艺条件为料液比1:30 (g:mL),提取温度81℃,提取时间75 s,此条件下,油茶叶多糖得率为8.43％.油茶叶多糖对DPPH·、·ABTS+、OH·都有很强的清除能...     

多级离心逆流萃取萘普生对映体模拟及实验研究

基于萘普生(NAP)对映体的单级手性萃取数学模型和质量守恒定律,建立了多级离心逆流萃取萘普生对映体数学模型。采用Matlab语言编写程序模拟了相比、萃取剂浓度、水相pH值等参数对萃取相出口对映体过剩量和产率的影响,并经实验研究对模型模拟进行验证。结果表明:采用中间进料,对映体浓度[R,S-NAP]=0.025 mol·L^-1、萃取剂浓度[C]=0.050 mol·L^-1、相比W/O=7、水相pH=2.5、温度T=5℃时,经10级离心逆流萃取后萃取相出口S-NAP对映体过剩量为45%,相应的产率60%,实验结果和模型模拟值符合得很好。     

双相（O/W）识别手性萃取分离多巴对映体研究

为了研究多巴在D（L）-2酒石酸异丁酯1,2二氯乙烷有机相和羟丙基-β-环糊精水相萃取体系中的分配行为;运用双相（O/W）识别手性萃取,考察酒石酸构型和浓度、羟丙基-β-环糊精浓度、水相pH值等因素对萃取性能的影响。羟丙基-β-环糊精对S-多巴对映体的识别能力大于对R-多巴对映体的识别能力,而L-酒石酸异丁酯的识别能力刚好相反;在羟丙基-β-环糊精和L-酒石酸异丁酯萃取体系中,多巴外消旋体一次萃取分离后R和S对映体的分配系数（kR和kS）分别为8.92和5.34,分离因子α达1.67;同时pH值和萃取剂浓度对手性分离能力有显著的影响。双相（O/W）识别手性萃取具有较强的手性分离能力,它对外消旋体化合物的制备性分离有着十分重要的意义。     

新型除磷填料的制备及除磷吸附床运行参数的优化

为解决现有除磷吸附剂粒径小造成的材料易流失和系统压降过大等问题,以实现吸附除磷工艺在实际工程中的应用,以聚氨酯填料为载体,水溶性聚氨酯为介质,将水化硅酸钙负载到聚氨酯填料上制成负载型除磷填料。研究了制备条件对除磷填料除磷效果的影响,采用扫描电子显微镜（SEM）和傅里叶变换红外光谱仪（FTIR）观察分析了负载前后水化硅酸钙微观结构及化学基团的变化;利用除磷填料作为除磷吸附床的滤料,研究了运行条件对吸附床除磷效果的影响。在此基础上,利用响应曲面法研究了除磷吸附床磷酸盐去除率和各变量之间的关系,并对工艺参数进行了优化。结果表明,水性聚氨酯溶液的浓度和用量分别为100 g/L和50 ml,水化硅酸钙的质量为12 g的条件下所制备的除磷填料除磷效果最好;SEM和FTIR分析结果显示,水化硅酸钙负载前后其孔隙结构和化学基团没有明显的变化;预测模型的方差分析结果表明,HRT(X ₁)、进水ρ(PO₄ ^3--P)(X ₂)、温度(X ₃)、初始pH(X ₄)以及X ₁ X ₂,X ₁ X ₄,X ₂ X ₃,X ₂ X ₄的交互作用均对磷酸盐的去除具有显著影响 (P＜0.05),但X ₁ X ₃的交互作用对磷酸盐的去除影响不显著。通过预测模型获得的最佳运行条件为：HRT为79.77 min,进水ρ(PO₄ ^3--P)为1.70 mg/L, 温度为34.04℃,pH为9.68。在该条件下,反应器对磷酸盐的去除率可以达到93.46%。     

离子液体提取构树叶总黄酮的工艺

以构树叶为研究对象,研究了离子液体苯并噻唑甲烷磺酸盐在总黄酮提取工艺上的应用,采用Al（NO₃）₃-NaNO₂比色法测定了构树叶中总黄酮的含量。通过单因素试验,以构树叶中总黄酮提取率为指标,探讨了离子液体浓度、乙醇体积分数、提取温度、提取时间、料液比对构树叶中总黄酮提取率的影响。实验结果表明在离子液体浓度0.5mol/L、乙醇体积分数60%、提取温度60℃、提取时间20 min、料液比1：20的工艺条件下,测得构树叶总黄酮含量为0.4685mg/g。该提取工艺操作简单、合理、提取效率较高。     

具有羧酸官能团的功能性离子液体萃取分离钇的研究(英文)

A new kind of hydrophobic ionic liquids [1-alkyl-3-(1-carboxylpropyl)im][PF6] has been synthesized,and their extraction properties for Y(III) in the nitric acid medium was also investigated.The effects of extractant concentration,equilibrium pH of aqueous phase,salt concentration,temperature etc.were discussed.The results show that this kind of Task-Specific Ionic Liquid(TSIL) needs to be saponified before being used for the Y(III) ex-traction,and the extraction is acid dependent,and the extraction efficiency increases with the aqueous phase acidity decreasing.Furthermore,the loaded organic phase is easy to be stripped;more than 95% Y(III) could be stripped from the loaded organic phase when the stripping acidity is higher than 0.07 mol?L?1.The slope analysis technique is used to investigate the extraction mechanism,and a possible cation-exchange extraction mechanism is proposed in the present extraction system.     

Chiral separation of mandelic acid by temperature‐induced aqueous two‐phase system

BACKGROUND: R‐mandelic acid is an important chiral pharmaceutical intermediate, which is commonly obtained by biotransformation. This work has focused on using novel chiral recognition technology, aqueous two‐phase extraction, for the chiral separation of mandelic acid. RESULTS: The copper (II) formed a 2:1 complex with β‐CD in an alkaline solution, which was isolated from solution by the addition of ethanol. The complex structure was characterized by IR and UV spectroscopy. The chiral recognition system was established by adding Cu₂‐β‐CD into the triton‐114 aqueous two‐phase extraction system, which preferentially recognizes the (R)‐enantiomer rather than the (S)‐enantiomer. Factors affecting the extraction mechanism were analyzed, namely the concentration of Cu₂‐β‐CD and tritonX‐114, the types of salts, pH, and temperature. It was found that the concentration of Cu₂‐β‐CD and temperature were the most important influencing factors for chiral separation of mandedlic acid. The experimental results showed that the ee values increased with pH and concentration of trition‐114, and the maximum ee was 67.91%. The addition of inorganic salt had a strong influence on ee, which decreased when salt was added into the aqueous two‐phase extraction system. CONCLUSION: A novel chiral recognition technology ‐ aqueous two phase extraction is reported in this paper.The tritonX‐114 aqueous two phase system have a good recognition ability for mandelic acid. Copyright © 2012 Society of Chemical Industry     

硝酸法磷酸脱氟工艺研究

针对以硝酸法湿法磷酸直接制备饲料级磷酸氢钙存在磷氟比（五氧化二磷与氟的质量比）较低的问题,采用化学沉淀法,以钙盐作为脱氟剂,通过间歇实验考察了反应时间、反应温度、反应pH、酸解液中五氧化二磷和氧化钙浓度等因素对酸解液中磷沉淀率和磷氟比的影响。结果表明,反应时间和反应温度的变化对溶液的磷沉淀率和磷氟比影响不大,而降低五氧化二磷和氧化钙的浓度能够有效地提高溶液的磷氟比、降低磷沉淀率。通过对比脱氟溶液制备饲料级磷酸氢钙的收益变化可得出较优操作条件：反应温度为40 ℃,反应时间为20 min,酸解液中五氧化二磷质量分数为7.6%、氧化钙质量分数为3.4%,钙盐中和溶液pH为2.4。在此条件下,脱氟溶液的磷氟比达到230以上、磷损失率小于30%,可为后续饲料级磷酸氢钙的制备提供合格的原料。     

Characterization of four diol dehydrogenases for enantioselective synthesis of chiral vicinal diols

Enantiopure vicinal diols are important building blocks used in the synthesis of fine chemicals and pharmaceutical compounds. Diol dehydrogenase(DDH) mediated stereoselective oxidation of racemic vicinal is an efficient way to prepare enantiopure vicinal diols. In this study, four new bacterial DDHs(AnDDH from Anoxybacillus sp. P3 H1 B, HcDDH from Hazenella coriacea, GzDDH from Geobacillus zalihae and LwDDH from Leptotrichia wadei) were mined from the GenBank database and expressed in E. coli T7...     

卤醇脱卤酶催化合成(R)-1-氯-3-苯氧基-2-丙醇的工艺优化

以卤醇脱卤酶重组湿菌体E. coli BL21（pET28a-HHDH）为催化剂,催化外消旋的1-氯-3-苯氧基-2-丙醇的动力学拆分可以获得光学纯的(R)-1-氯-3-苯氧基-2-丙醇。本文系统地研究了卤醇脱卤酶催化合成光学纯(R)-1-氯-3-苯氧基-2-丙醇的影响因素,对反应pH、反应温度、菌体浓度、亲核试剂 {\mathrm{N}}_{\mathrm{3}}^{-} 浓度和底物浓度进行了探究。结果表明,卤醇脱卤酶催化合成(R)-1-氯-3-苯氧基-2-丙醇的最佳工艺条件为：pH为7.0,反应温度为28℃,菌体浓度为22.5g/L,亲核试剂NaN₃的浓度为50mmol/L,底物外消旋1-氯-3-苯氧基-2-丙醇的浓度为10mmol/L。在此工艺条件下,(R)-1-氯-3-苯氧基-2-丙醇的ee值和收率分别为100%和16.97%。     

水溶性β-环糊精反应萃取分离苯基琥珀酸对映体的平衡研究

This paper deals with the enantioseparation of phenylsuccinic acid (H2A) enantiomers by liquid-liquid reactive extraction using β-CD derivatives as aqueous selectors. Cyclodextrin and its derivatives can interact with guest molecules selectively to form complexes with different stabilities. Cyclodextrin derivatives are not soluble in organic liquids, but highly soluble in water. In this work, hydroxypropyl-β-cyclodextrin (HP-β-CD), hydroxyethyl- β-cyclodextrin (HE-β-CD) and methyl-β-cyclodextrin (Me-β-CD) were selected as chiral selectors in aqueous phase for the reactive extraction of phenylsuccinic acid enantiomers from organic phase to aqueous phase. The results show that the efficiency of the extraction depends, often strongly, on a number of process variables, including the types of organic solvents and β-CD derivatives, the concentrations of the extractants and H2A enantiomers, pH and temperature. HP-β-CD, HE-β-CD and Me-β-CD have stronger recognition abilities for R-phenylsuccinic acid than for S-phenylsuccinic acid. Among the three kinds of β-CD derivatives, HP-β-CD has the strongest separation ability. Excellent enantio-separation was achieved under the optimal conditions of pH of 2.5 and temperature of 5°C with a maximum enantioselectivity (a) of 2.38. Reactive extraction of enantiomers with hydrophilic β-CD derivatives is of strong chiral separation ability and can be hopeful for separations of various enantiomers at a large-scale.     

高效功能菌群RR的筛选及其群落分析

利用梯度浓度压力驯化法, 从厌氧反应器中筛选出对直接红28有具有良好脱色能力的混合菌群RR。在染料初始浓度为200mg/L, pH=7.0, 温度为35℃条件下, 经48h静止培养, 染料脱色率可达96.16%。进一步对其培养条件如pH值、温度、盐度、初始染料浓度等进行了脱色研究, 结果表明, 在pH=7、温度为45℃, 盐度为2mmol/L的情况下, 功能菌群脱色效果达到最佳。为了进一步适应工程无机条件, 筛选出以染料作为唯一氮源、碳源以及能量的功能菌群, 遂将培养基中葡萄糖去掉, 同样利用梯度浓度压力驯化法, 筛选出混合菌群RM, 并对其脱色性能及群落结构进行分析。混合菌群RM在染料初始浓度为50mg/L、温度为35℃、pH=7.0条件下, 48h后其脱色效率为20.05%。利用变性梯度凝胶电泳(DGGE)法, 对群落进行分析, 混合菌群RR主要为伯克霍尔德氏菌属(Burkholderia sp.)、链球菌属(Streptococcus)和克雷伯氏菌属(Klebsiella sp.), 菌群RM主要为伯克霍尔德氏菌属(Burkholderia sp.), 可见伯克霍尔德氏菌属菌株(Burkholderia sp.)可以适应工程无机环境, 并对直接红28存在一定的降解能力。     

聚季铵盐辅助络合-超滤提取钨(Ⅵ)(英文)

Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (Ⅵ) before ultrafiltration. Tungsten (Ⅵ)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration membrane in the complexation-ultrafiltration process. Effects of various operating parameters such as polymer metal ratio(PMR), pH and chloride ion concentration on permeate flux (J) and tungsten rejection coefficient (R) were investigated. The integration of four experiments including concentration, decomplexation, diafiltration and reuse of regenerated polymer was carried out. In the process of concentration, J declines slowly and R is about 1 at PMR of 3 and pH of 7. Tungsten concentration in the retentate increases linearly with volume concentration factor. Tungsten is concentrated efficiently with the membrane. The concentrated retentate was used further for the decomplexation. It takes about 6 min to reach the decomplexation equilibrium at chloride ion concentration of 50 mg·L-1 . The decomplexation percentage of tungsten (Ⅵ)-PQ6 complex reaches 56.1%. In the diafiltration process, tungsten (Ⅵ) can be extracted effectively by using 50 mg·L-1 chloride ion solution, and the purification of the regenerated PQ6 is acceptably satisfactory. The regenerated PQ6 was used to bind tungsten (Ⅵ) at various pH values. The binding capacity of the regenerated PQ6 is close to that of fresh PQ6, and the recovery percentage of binding capacity is higher than 90%.     

木瓜蛋白酶在离子液体双水相中的分配行为

采用离子液体双水相提取木瓜蛋白酶。首先考察不同浓度、pH、温度的离子液体对木瓜蛋白酶活性的影响, 其次考察不同离子液体双水相体系、离子液体侧烷基链长度及浓度、酶添加量、pH、温度对木瓜蛋白酶分配行为的影响。结果表明:[C₄mim]Cl和[C₄mim]Br体系萃取木瓜蛋白酶的效果比[C₄mim]BF₄体系好;高温(≥60℃)对离子液体双水相体系萃取木瓜蛋白酶不利。离子液体双水相萃取木瓜蛋白酶的最佳工艺条件:0.25 g·ml^-1的[C₄mim]Cl, 0.35 g·ml^-1的K₂HPO₄, pH 8.0, 酶添加量2.0 mg·ml^-1, 30℃。此条件下木瓜蛋白酶的酶活性回收率达到95.16%, 纯化因子达到1.5。为今后进一步研究该体系的放大实验或规模化生产奠定了基础。     

Efficient production of cyclic adenosine monophosphate from adenosine triphosphate by the N-terminal half of adenylate cyclase from Escherichia coli

In this study, we aimed at developing an efficient biocatalytic process for bio-production of cyclic adenosine monophosphate (cAMP) from adenosine triphosphate (ATP). First, adenylate cyclase from Escherichia coli MG1655 (EAC) and Bordetella Pertussis (BAC) were expressed in E. coli BL21 (DE3) and comparatively analyzed for their activities. As a result, EAC from E. coli MG1655 exhibited a higher activity. However, amount of EAC were obtained in an insoluble form. Therefore, we expressed the first 446 amino acids of EAC (EAC446) to avoid the inclusion body. The effects of induction temperature, incubation time, and incubation pH were further evaluated to improve the expression of EAC446. Subsequently, the reaction process for the production of cAMP with ATP as a starting material was investigated. As none of cAMP was detected in the whole-cell based biocatalytic process, the reaction catalyzed by the crude enzyme was determined for cAMP production. What's more, the reaction temperature, reaction pH, metal ion additives and substrate concentration was optimized, and the maximum cAMP production of 18.45 g·L^-1 was achieved with a yield of 95.4% after bioconversion of 6 h.     

耐低温对硝基苯酚降解菌的降解动力学研究

以对硝基苯酚在10℃条件下的微生物降解过程为研究对象,融合单因素实验、细胞疏水性实验、细胞膜通透性实验与降解动力学实验探究菌株Pseudomonas sp. ZL对对硝基苯酚的低温降解特性。实验结果表明,在10℃条件下菌株Pseudomonas sp. ZL能够耐受并降解303.71 mg·L^-1的对硝基苯酚,最佳降解条件为pH=8.0,0.5% NaCl,1 g·L^-1 NH₄NO₃,该条件能够显著促进对硝基苯酚的降解速率并大大缩短降解的延迟时间。在10℃、单因素最佳条件下,对硝基苯酚降解菌的抑制降解动力学拟合符合Aiba模型,其中μ_max（最大比生长速率）为0.205 h^-1,K_s（半饱和系数）为3.40 mg·L^-1,K_i（底物抑制系数）为166.86 mg·L^-1,因此166.86 mg·L^-1即为该条件下菌株的低温降解抑制浓度。与其他降解菌株相比,菌株Pseudomonas sp. ZL的K_i和μ_max/K_s较大、K_s/K_i值较小,说明对硝基苯酚对该菌株的抑制作用较小,菌株的有效利用率更高,在原位修复低温地下水及土壤污染方面具有较高的应用潜力。     

NbO x 掺杂对Pt/TiO2催化燃烧氯乙烯的促进作用

通过制备Pt/Nb _x /TiO₂研究了NbO _x 在催化燃烧氯乙烯中的作用;采用XRD、XPS、H₂-TPR、NH₃-TPD与Py-FT-IR表征了NbO _x 对于催化剂组织结构、氧化还原以及酸碱性的影响。负载NbO _x 可促进Pt/TiO₂反应性能的提高,当Nb/Ti摩尔比为0.09时,即Pt/Nb_0.09/TiO₂可在246℃实现90%氯乙烯的转化;与Pt/TiO₂相比,达到相同转化率的温度向低温偏移69℃。NbO _x 也影响了催化燃烧过程中的含氯副产物的总浓度和分布。催化剂表征结果发现NbO _x 的引入可进一步增加Pt与载体（TiO₂）之间的相互作用,提高催化剂的表面活性氧物种的浓度,进而促进了催化剂氧化还原性能的提高。催化剂表面的总酸量随着NbO _x 含量的增加而降低,尤其是表面Lewis酸量。因此,催化剂表面的酸量和酸分布不是决定反应性能的唯一因素,而低温的氧化还原性更有利于催化剂性能的提高。     

钒铬还原渣酸浸液中钒铬初步分离工艺

钒铬还原渣是钠化提钒过程的典型危险固体废弃物,其资源化利用需求迫切。中国科学院过程工程研究所提出钒铬还原渣硫酸酸解-钒铬初步分离-铬/钒/铁络合深度分离技术路线,并在攀钢集团建成万吨级示范工程。本文重点考察钒铬还原渣酸解液中钒铬初步分离原理及工艺,研究了H₂O₂和Na₂S₂O₈两种氧化剂对沉钒效果的影响,并通过实验确定了最佳工艺条件。结果表明：以H₂O₂为氧化剂时,H₂O₂与钒摩尔比为0.75、氧化温度为60℃、初始溶液pH为2.0、氧化时间为60min、水解温度为95℃、水解时间为2.5h的条件下可得到84.2%的沉钒率;以Na₂S₂O₈为氧化剂时,Na₂S₂O₈与钒摩尔比为0.65、氧化温度为90℃、氧化时间为45min、沉钒初始溶液pH为2.5、沉钒温度为90℃、沉钒时间为2.5h的条件下可获得93.1%的沉钒率。过硫酸钠氧化过程温和,沉钒率高,铬损失小,更适合工业推广应用。采用SEM获得了沉淀产物的微观形貌,煅烧后得到V₂O₅产品,采用XRF获得了产品组成,通过X射线衍射确定得到的V₂O₅产品为正交晶型。