从发酵液中分离ε-聚赖氨酸的树脂筛选

筛选适合分离纯化发酵液中ε-聚赖氨酸的树脂并确立纯化工艺参数。以树脂对ε-聚赖氨酸的吸附量、解吸附率为评价指标,选用HZD-5、D113、D152、D155、HD-2、DK110 6种树脂进行筛选。结果表明,HD-2型树脂吸附与洗脱效果最佳,上柱发酵液pH为8并且流速为4mL/m in,洗脱液为0.075mol/L的盐酸、流速2.5mL/m in。经活性炭脱色、旋转蒸发仪浓缩后得ε-聚赖氨酸粗品,纯度可达81.2%,回收率98.3%。     

新型大孔吸附剂——H系列吸附树脂的合成和应用

自六十年代以来,随着大孔离子交换树脂的问世,大孔吸附树脂也得到了很快的发展。美国罗姆哈斯公司生产的Amberlite XAD系列和日本三菱化成公司生产的Diaion HP系列吸附树脂在许多领域得到广泛的应用,特别有效地应用于发酵液中抗菌素和生物活性物质的提取(如头孢菌素的提取)和脱色。我国现在研制生产的吸附树脂大多是以二乙烯苯为交联剂的苯乙烯、丙烯酸甲酯或丙烯腈与二乙烯苯的大孔共聚物,具有较高的比表面积和孔穴率,在脱色、分离、色谱和药物提取上也取得较好的应用效果。     

川芎多糖脱色方法比较

比较了活性炭、H2O2和大孔吸附树脂对川芎多糖提取液的脱色效果。选用极性大孔树脂S-8在工作液流速为2BV/h,川芎浓度为0.33g/mL时,脱色率为92.7%,多糖保留率为93.0%,表明S-8适合用于川芎多糖提取液脱色。     

Ag+及其配合物在活性炭上吸附行为研究

研究了配位体和氧化改性对活性炭吸附Ag^ 及其配合物的影响以及银在活性炭表面的分布特征。结果表明：(1)活性炭对Ag^ 的吸附非常快,且不受离子强度的影响．但当Ag^ 形成[Ag(NH3)2]^ 和[Ag(S2O3)2]^3-后在活性炭上吸附性能下降,氨水浓度增加对[Ag(NH3)2]^ 的吸附没有影响,而还原性的Na2S2O3浓度增加使[Ag(S2O3)2]^3-的吸附下降。(2)银主要分布在活性炭的外表面,Ag^ 浓度和吸附时间不同将导致银颗粒的分布及粒径也不同,合理控制Ag^ 浓度和吸附时间,就可以在活性炭表面负载纳米金属银．(3)活性炭氧化改性不利于Ag^ 和[Ag(S2O3)2]^3-的吸附,却有利于[Ag(NH3)2]^ 的吸附。     

六元瓜环修饰的花团状铜的催化活性

采用水热法,将六元瓜环(Q[6])分散的五水硫酸铜用抗坏血酸还原后获得了六元瓜环修饰的超微花团状铜(Q[6]-Cu花团).利用X射线粉末衍射(XRD)和扫描电子显微镜(SEM)对产物进行了结构和形貌表征,通过催化氧化染料罗丹明B(Rh B)、结晶紫(CV)、茜素红(AR)和次甲基蓝(MB)考察了产物的催化性能.结果表明,Q[6]-Cu花团直径约为2.0μm.在Q[6]-Cu/H_2O_2体系中,0.08 g/L的Q[6]-Cu在300 min内对染料脱色效率均超过87%.     

吸附树脂法在泽泻提取物的脱色及高纯度泽泻醇制备中的应用研究

将具有脱色和吸附双重功能的新型吸附树脂用于泽泻提取物的脱色和高纯度泽泻醇提取物的制备工艺中,考察了树脂结构对脱色性能和吸附性能的影响熹见律.结果表明,兼具适宜的比表面积和功能基含量的No.2树脂具有最佳的纯化效果,只通过"吸附-解吸"一步工艺,产品纯度即可从1.93%提高到50%以上,泽泻醇的回收率高于95%.初步探讨了树脂的吸附机理,认为树脂对泽泻醇的吸附是单纯的疏水性作用力,而对色素的吸附应为疏水-离子交换双重作用的协同效应.     

大孔吸附树脂法柚皮果胶脱色工艺研究

比较了AB-8、S-8、X-5、聚酰胺、NKA-Ⅱ、NPD-600等6种大孔吸附树脂对柚皮果胶的脱色效果.在静态吸附试验研究的基础上,筛选出效果较好的树脂进行动态试验研究.实验表明:AB-8型大孔吸附树脂对柚皮果胶提取液具有较好的吸附脱色效果和较低的果胶损失率,该树脂对柚皮果胶脱色的适宜工艺参数为:室温(约20℃),流速3BV/h,溶液处理量为5BV,上柱液pH值为4～6.此工艺对果胶提取液中色素的吸附率约80%.树脂吸附后可用70%乙醇进行洗涤再生,果胶提取液脱色后经喷雾干燥所得的果胶成品质量符合QB2484-2000标准.     

高选择性吸附树脂结构设计及在天然产物提取分离中的应用

大孔吸附树脂因其结构易于调控、吸附选择性高、可再生使用等诸多优点,在天然植物有效成分的提取分离中发挥了重要作用。本文介绍了近年来在高选择性吸附树脂结构设计方面的研究进展,主要分为两个方面:(1)基于多重弱相互作用的协同效应设计树脂骨架结构,针对吸附质分子结构特点,在树脂骨架上引入能发生氢键、静电、偶极作用的特殊功能基团,并有目的地调控树脂的疏水骨架,可用于天然植物中每一类有效成分的高纯度提取,甚至每一类有效成分的单体组分的分离;(2)树脂孔结构的调控,主要集中在改变传统的非良溶剂致孔的方法,利用聚付氏烷基化反应在树脂初始聚苯乙烯结构之间引入亚甲基刚性交联桥,得到孔径均匀的吸附树脂,使得此类树脂兼具了吸附和筛分的双重功能。     

树脂基球状活性炭的制备及对二氧化碳吸附性能的研究

以四种离子交换树脂(两种强碱性树脂D201和D280、两种弱碱性树脂D301G和D301R)为原料,经过磺化、炭化、活化处理制备了树脂基球状活性炭。采用TG、SEM、N2吸附等对球状活性炭的收率、表面形貌、比表面积进行了表征,研究了所制球状活性炭对CO2的吸附性能。结果表明,磺化处理有助提高树脂球的炭化收率;得到的四种球状活性炭对CO2吸附性能良好,强碱性树脂球原料比弱碱性树脂球更具有优势,其中,由强碱性树脂球D201制得的树脂球状活性炭在30℃下对CO2的吸附量可达2.57 mmol/g;十次循环吸附之后,树脂球仍能保持很好的CO2吸附性能。     

乳化液膜清除未结合胆红素

高未结合胆红素症 (Ｈｙｐｅｒｂｉｌｉｒｕｂｉｎｅｍｉａ)是新生儿常见疾病 .胆红素在血液中的浓度过高 ,会伤害婴儿的大脑 (核黄疸 ) [1].肝昏迷患者的症状与胆红素在血液中含量过高也有直接关系 ,迅速有效地将其清除可使患者症状缓解[2 ],迄今为止 ,清除胆红素的研究主要集中在以吸附剂吸附为基础的血液灌流方法 ,所用的吸附剂主要有活性炭和大孔吸附树脂 ,活性炭的吸附选择性和血液相容性都比较差 ;大孔吸附树脂的吸附选择性和血液相容性等方面有待进一步提高[3],特别是在吸附未结合胆红素时 ,清除率低、清除速度慢 ,难以满足临床方面…     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.