氧化淀粉基高吸水性树脂的制备及表征

以过硫酸铵为引发剂,N,N’-亚甲基双丙烯酰胺为交联剂,制备氧化淀粉―丙烯酸―丙烯酰胺高吸水性树脂,并采用红外光谱、X射线衍射等手段对产品的结构进行表征。通过单因素实验优化其制备工艺,最佳工艺条件为:氧化淀粉基体用量为50%,丙烯酸/丙烯酰胺质量比为4∶1,丙烯酸中和度为70%,引发剂过硫酸铵用量为0.5%,交联剂N,N’-亚甲基双丙烯酸胺用量为0.15%,反应温度为80℃,反应时间为3 h。此条件下,氧化淀粉基高吸水性树脂的吸水率达到972.4 g/g。     

丙烯酸与丙烯酰胺共聚制备高吸水性树脂

采用溶液聚合法,以N,N’-亚甲基双丙烯酰胺（NMBA）为交联剂,过硫酸钾（KPS）为引发剂合成了高吸水性树脂聚（丙烯酸-丙烯酰胺）（P（AA—AM））,研究了单体配比、丙烯酸中和度、引发剂及交联剂用量、反应温度对树脂在去离子水和0．9％盐水中吸水率的影响．最佳条件下制备的树脂在去离子水中吸水率为750g·g^-1,在0．9％盐水中吸水率为85g·g^-1．     

碳纳米管复合聚丙烯酸钠的制备及吸水性能

以过硫酸铵(APS)为引发剂,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备了碳纳米管/聚丙烯酸钠高吸水树脂。系统考察了碳纳米管质量分数、引发剂、交联剂和聚合温度对树脂吸水性能的影响。结果表明,以单体丙烯酸质量为基准,当交联剂,引发剂和碳纳米管质量分数分别为0.04%、0.3%和0.3%,聚合温度75℃时,所合成树脂的吸水性能最佳。添加碳纳米管后树脂表面粗糙和形成孔结构导致了其吸水性能的变化,使得碳纳米管/聚丙烯酸钠的吸水量和吸水速率明显提高,其吸去离子水和生理盐水能力分别达到1423和104g/g。该树脂重复吸水5次后,其吸水能力为1081.5g/g,达到最大吸水倍数的76.0%。     

速溶型高吸水性树脂的制备及性能研究

以丙烯酸为单体，Ｋ＿２Ｓ＿２Ｏ＿８为引发剂，Ｎ，Ｎ’－亚甲基双内烯酰胺为交联剂，进行反相乳液聚合，制得内交联高吸水性树脂。研究了聚合物吸水性能与内烯酸浓度，丙烯酸中和度，引发剂用量，交联剂用过的关系。考察了该树脂的吸水速率，保水性，在不同电解质溶液中的吸水速度及水饱和树脂在盐水中的失水率。     

PSY-g-PAA/Na-MMT复合高吸水性树脂的制备及其对Cu2+的吸附

以欧车前胶(PSY)、丙烯酸(AA)和钠基蒙脱土(Na-MMT)为原料,过硫酸铵(APS)为引发剂,N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备了欧车前胶接枝聚丙烯酸/钠基蒙脱土(PSY-g-PAA/Na-MMT)复合高吸水性树脂.考察了Na-MMT质量分数对复合高吸水性树脂吸水能力和Cu2+吸附...     

辉光放电电解等离子体引发合成聚丙烯酸钠/腐植酸复合高吸水性树脂

以丙烯酸和腐植酸为原料,N,N-亚甲基双丙烯酰胺为交联剂,在水溶液中采用辉光放电电解等离子体引发聚合反应制备聚丙烯酸钠/腐植酸复合高吸水性树脂。 考察了放电电压、交联剂、丙烯酸中和度、后聚合温度、腐植酸钠和丙烯酸的含量对树脂吸水率的影响,讨论了树脂在0.9%氯化钠溶液中的溶胀速率和不同pH值溶液中的溶胀行为。 用红外光谱和热重分析分别对产物进行了结构表征和稳定性测试,结果表明,最佳的合成条件为：放电电压470 V、交联剂质量分数为0.6%、腐植酸钠质量分数为4%、丙烯酸质量分数为10%、中和度60%、后聚合温度70 ℃。 所得复合树脂对蒸馏水的吸水率为1152 g/g,对0.9%NaCl溶液的吸水率为89 g/g,800 ℃后复合树脂残留率为44.3%。     

PAA/PVA SIPN高吸水性树脂的制备及性能研究

采用水溶液法合成了聚丙烯酸-聚乙烯醇(PAA-PVA)半互传网络型高吸水性树脂,其工艺条件的优化结果为:丙烯酸(AA)与PVA质量比为10∶0.5,AA中和度为80%,加入AA单体质量0.14%的引发剂和0.025%的交联剂,产物吸水率为530g/g,吸盐水率达63g/g。并采用红外光谱法表征了半互穿网络结构的形成。     

丙烯酰胺与玉米淀粉接枝共聚物的合成及其吸水性能研究

本文以硝酸铵为引发剂N，N-亚甲基双丙烯酰胺为交联剂，将丙烯酸胺与玉米淀粉接枝共聚合成了吸水剂。实验表明，当脱水葡萄糖单元与丙烯酰胺摩尔比为1：4，交联度为0．2％时，其吸水率最高可达18g／g，其对1％食盐水的吸收率为其吸水率的90％左右。然后，将以上吸水树脂以10％NaOH于60℃水解3h，制备了另一种吸水剂，吸水率约提高了16倍，但其吸1%食盐水的能力只有其吸水能力的10％左右。     

反相悬浮聚合AA-AM-HEMA三元共聚高吸水性树脂的研究

以丙烯酸（AA）、丙烯酰胺（AM）、丙烯酸羟乙酯（HEMA）为单体、N,N'-亚甲基双丙烯酰胺为交联剂、过硫酸铵/亚硫酸氢钠为氧化还原引发剂、Span80/Tween80为复合悬浮分散剂，采用反相悬浮聚合法合成了AA-AM-HEMA三元共聚高吸水性树脂。研究了单体用量、分散剂用量、油水比和粒径等对树脂性能的影响。用TGA和DSC对树脂的保水性和脱水动力学进行了研究，IR分析证实所合成的树脂为丙烯酸-丙烯酰胺-丙烯酸羟乙酯三元共聚物。     

丙烯酸-丙烯酰胺原位插层共聚制备高吸水性蒙脱土纳米复合材料的研究

在钠基蒙脱土(MMT)悬浮液中，采用丙烯酸(AA)和丙烯酰胺(AM)两种单体进行原位插层共聚，得到高吸水性纳米复合材料。研究了引发剂和交联剂对材料吸水率的影响。X射线衍射(XRD)结果表明：复合材料中蒙脱土片层001面的层问距随mMMT／mM的减小而增大，当mMMT／mM≤1／3时，复合材料中的蒙脱土已完全剥离。DSC测试表明，在蒙脱土含量较低时，其玻璃化转变温度Tg随MMT含量的升高逐渐提高。吸水速率和保水能力测试结果表明，材料吸收去离子水能力达610g／gR，吸收盐水(wNaCl=0．009)能力达89g／gR。蒙脱土片层的引入。在一定程度上提高了材料的初期吸水速率和加压下的保水能力。     

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.     

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.