AM/(2-甲基丙烯酰氧乙基)三甲基氯化铵/2-丙烯酰胺基-2-甲基丙基磺酸钠的反相微乳液共聚合动力学研究

通过实验绘制了失水山梨醇单月桂酸酯(Span20)-聚氧乙烯山梨醇酐单脂酸酯(Tween80)复配乳化剂、丙烯酰胺、(2-甲基丙烯酰氧乙基)三甲基氯化铵、2-丙烯酰胺基-2-甲基丙基磺酸钠和环己烷的拟三元相图.采用过硫酸铵-亚硫酸氢钠氧化还原引发剂,通过动力学研究,得到了聚合反应的表观活化能为68.10 kJ/mol,并分别得到了聚合速率与产物特性粘数的动力学关系式Rp∝[M]1.74[APS]0.60[E]-1.28,[η]∝[M]0.78[APS]-0.23[E]-0.71,分析了单体浓度、引发剂浓度、乳化剂浓度对共聚合反应速率Rp和共聚物特性粘数[η]作用及影响的原因,在动力学研究的基础上初步探讨了聚合机理.     

含氨基、羟基丙烯酸乳液聚合的稳定性

采用间歇及半连续乳液聚合方式,以过硫酸铵/亚硫酸钠为引发体系,合成了甲基丙烯酸甲酯/丙烯酸丁酯/甲基丙烯酸羟乙酯/甲基丙烯酸二氨基乙酯四元共聚物胶乳.系统研究了乳化剂种类和浓度、聚合温度、乳化单体进料方式及进料速率对聚合过程稳定性的影响.聚合温度降低,乳化单体进料速度减慢有利于聚合过程的稳定,采用种子半连续聚合方式比间歇聚合过程更稳定,乳化剂浓度的增加有利于聚合稳定性的提高和乳胶粒子的均匀化.     

VAC与甲基丙烯酰氧乙基三甲基氯化铵无皂乳液共聚合动力学研究

研究了醋酸乙烯酯 (VAC)与甲基丙烯酰氧乙基三甲基氯化铵 (DMC)无皂乳液共聚合动力学 ,考察了引发剂偶氮二异丁基脒盐酸盐 (AIBI)浓度、单体浓度、温度等因素对聚合反应速率的影响 ,得到单体总浓度和引发剂浓度影响反应速率的动力学方程为 :Rp=k1 [M]0 6 3[AIBA]1 0 ;各单体浓度影响反应速率的动力学方程为 :Rp=k2 [VAC]0 1 6 [DMC]0 89.聚合表观活化能为 4 4 0 1kJ·mol- 1 ,初步探讨了聚合反应机理 .     

表面活性单体AMC14AB在水溶液中的聚合动力学研究

采用溴酸钾-溴化钾法研究了阳离子型表面活性单体(2-丙烯酰胺基)乙基十四烷基二甲基溴化铵(AMC14AB)在水溶液中的聚合动力学,分别考察了引发剂浓度与单体浓度对聚合速率的影响,确定了聚合速率方程,分析了聚合机理,考察了温度对聚合反应的影响,测定了聚合表观活化能。研究结果表明,由于AMC14AB在水溶液中的胶束化行为,使其具有较快的聚合速率,于60℃下聚合,40min内转化率即可达到80%以上;AMC14AB的聚合速率方程为Rp=k[M]0.92[I]0.48,说明链终止为双基终止方式,引发过程与单体无关;聚合表观活化能为80.72kJ/mol。     

氯丁胶乳乳液接枝甲基丙烯酸甲酯的反应动力学

采用乳液聚合法将甲基丙烯酸甲酯(MMA)接枝到氯丁胶乳上,红外光谱和核磁共振氢谱证实了接枝产物的生成。 研究了反应温度、乳化剂浓度、引发剂浓度和单体浓度对表观聚合速率的影响。 结果表明,当反应温度为50 ℃,引发剂叔丁基过氧化氢 四乙烯五胺（t-BHP/TEPA）用量为氯丁胶乳干重的0.5%,单体/聚合物质量比m(M)∶m(P)=3∶5,乳化剂十二烷基连苯醚二磺酸钠（DSB）用量为单体总质量1%时,单体转化率和接枝效率分别为99.1%和54.9%。 聚合反应动力学关系式为：Rp=Kc(E)0.15c(I)0.30c(MMA)1.41,式中,K为常数,在40~55 ℃范围内,聚合反应的表观活化能Ea＝60.2 kJ/mol。 接枝聚合基本符合自由基反应机理。     

4,4′-偶氮二[4-氰基戊酰(对-二甲基氨基)苯胺]引发丙烯酰胺聚合及其动力学研究

以N,N-二甲基甲酰胺(DMF)为溶剂,研究了4,4′-偶氮二[4-氰基戊酰(对-二甲基氨基)苯胺](ACPDA)为引发剂引发丙烯酰胺(AAM)的聚合行为.考察了聚合反应温度、单体浓度和引发剂浓度对聚合物分子量和聚合反应速率的影响,测定了反应级数和聚合反应的活化能.实验结果表明,ACPDA引发AAM的聚合速率方程为Rp=K[AAM]1.03[ACPDA ]0.48,聚合反应的表观活化能(Ea)为126.44kJ·mol-1.     

淀粉-丙烯酸反相乳液接枝共聚反应的动力学研究

以过硫酸铵(NH4)2S2O8为引发剂,失水山犁醇单月桂酸酯(Span-20)为乳化剂,采用反相乳液聚合技术,制得了淀粉-丙烯酸接枝共聚物,研究了反应温度、引发剂浓度、单体浓度、乳化剂浓度、淀粉用量五种因素对反应速率的影响。根据单体的转化率,用线性回归法计算聚合反应速率;然后用作图法确定反应的动力学关系式,并求出反应起始阶段的表观活化能。结果表明,其动力学关系式为:Rp∝[(NH4)2S2O8]0.51[AA]1.18[St]0.81[Span-20]0.62;聚合反应恒速阶段的活化能,在53~68℃范围内为26.00 kJ.mol-1。     

高固含量丙烯酸酯的微乳液聚合

采用半连续滴加预乳液的微乳液聚合法,合成出聚合物质量分数40%、乳化剂质量分数2.5%的丙烯酸酯微乳液. 考察了单体滴加速度、乳化剂种类及其用量、电解质用量、温度和搅拌等因素对乳液粒径及性能的影响. 研究表明,聚合在相当于Winsor-Ⅰ型的聚合体系中进行,由纯单体相(滴入的单体)和O/W微乳相构成,上层单体只起储存库的作用,它在缓慢的搅拌帮助下扩散进入微乳相中,只要微乳液液面上补加的单体不扰动微乳液的平衡,即不会产生粗粒子. 单体滴加时间控制在4 h,选择质量分数为2.5%的Dowfax2A1/OP-10乳化体系,NaHCO3质量分数为0.16%,反应温度控制在75～80 ℃,搅拌速度控制在150 r/min,可使聚合反应平稳进行,得到了m(聚合物)∶m(乳化剂)=15∶1的丙烯酸酯微乳液.     

苯丙水溶胶的合成与性能研究(I) 聚合工艺和反应组分对聚合稳定性和胶体性能的影响

用一次投料法、半连续滴加法和单体预乳化法三种聚合工艺，合成了苯丙乳液聚合物，并加氨微细化，转化成水溶胶，考察了聚合工艺和反应组分（乳化剂，功能单体等）对苯丙乳液及其水溶胶反应稳定性和粒子大小及分布等胶体性能的影响。     

氯丁胶乳乳液接枝甲基丙烯酸甲酯反应动力学

采用乳液聚合法将甲基丙烯酸甲酯(MMA)接枝到氯丁胶乳上,红外光谱和核磁共振氢谱证实了接枝产物的生成。研究了反应温度、乳化剂浓度、引发剂浓度和单体浓度对表观聚合速率的影响。结果表明,当反应温度为50℃,引发剂叔丁基过氧化氢-四乙烯五胺(t-BHP/TEPA)用量为氯丁胶乳干重的0.5%,单体/聚合物质量比m(M):m(P)=3:5,乳化剂十二烷基连苯醚二磺酸钠(DSB)用量为单体总质量1%时,单体转化率和接枝效率分别为99.1%和54.9%。聚合反应动力学关系式为:Rp=Kc(E)0.15c(I)0.30c(MMA)1.41,式中,K为常数,在40～55℃范围内,聚合反应的表观活化能Ea=60.2kJ/mol。接枝聚合基本符合自由基反应机理。     

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.