壳聚糖在1-乙基-3-甲基咪唑醋酸盐溶液中的流变行为

离子液体1-乙基-3-甲基咪唑醋酸盐（[EMIM]Ac）对壳聚糖具有良好的溶解能力。利用新一代旋转流变仪哈克MARS-Ⅲ考察了壳聚糖-[EMIM]Ac溶液的稳态流变和动态流变性能。稳态流变结果表明：当低黏均分子量壳聚糖离子液体溶液的质量分数在3%以下时,溶液呈牛顿性流体特征,高于此质量分数时溶液呈假塑性流体特征;壳聚糖离子液体溶液的黏度、结构黏度指数随着温度升高而降低;在同一质量分数下,溶液黏度随壳聚糖黏均分子量的增大而增加,溶液的恒剪切活化能黏流活化能随着剪切速率的增大而降低。动态流变结果表明：溶液的储能模量和损耗模量随着温度的升高而下降,储能模量与损耗模量存在一个交叉点,该交叉点随着温度升高向高频区移动。     

聚醚砜溶液流变性的研究

研究了聚醚砜（PES）/二甲基亚砜（DMSO）体系中PES的质量分数、原液温度对流变性的影响和原液中PES的质量分数对粘流活化能的影响,从而得出PES/DMSO体系属于切力变稀流体,非牛顿指数随着PES质量分数的增加而不断减小,随着溶液温度的升高而不断增大.     

HAP/P(MMA-St)复合微球的制备及其吸附性能

以微孔纳米羟基磷灰石（HAP）为无机载体,甲基丙烯酸甲酯（MMA）和苯乙烯（St）为聚合单体,采用悬浮聚合法制备了HAP/P(MMA-St)复合微球。研究了影响球体粒度及其分布的主要因素和微球的吸附性能。结果表明,表面活性剂用量（质量分数,下同）为1‰、MMA用量为2%,HAP用量为30%,转速为300r/min时复合微球的合格球收率最高为86.4%。当微球中HAP的含量为36.07%时,HAP/P(MMA-St)微球对牛血清蛋白的最大吸附量Qe=18.70 mg/g,比未加HAP时,增加了4.65 mg/g。     

PANI—PBOPy复合材料的制备及介电性能

采用甲基磺酸（MSA）掺杂聚苯胺（PANI）,并以MSA为溶剂,将其与聚（2,6-亚吡啶基）苯并二嗯唑（PBOPy）采用溶液共混法制备了不同PANI质量分数的PANIPBOPy复合材料。采用红外光谱、wXRD、Uv—Vis、TGA以及SEM对复合材料的结构和性能进行了表征。研究了PANI的质量分数、温度、频率等因素对PANIPBOPy复合材料导电性能和介电性能的影响。研究表明：当PANI的质量分数达到20％时,复合材料的电导率增大了10个数量级;复合材料的介电常数和介电损耗则随着PANI质量分数的增加呈现先增大后减小的趋势,随着频率的升高先迅速降低而后趋于稳定,并且随温度升高而增大,40℃时PANI质量分数为15％的复合材料的介电常数约为230。     

三偏磷酸钠交联黄原胶的制备及其溶液流变性

以三偏磷酸钠(STMP)为交联剂,合成了水溶性低交联度黄原胶(XG),依据其溶液粘度优化出了最佳合成条件;考察了电解质质量分数、pH值及温度对STMP交联黄原胶(简记为SP-c-XG)溶液流变性的影响,并与XG溶液进行了对比。 结果表明,在所研究的电解质(NaCl和CaCl₂)质量分数(0~5.0%)、pH值(2~11)和温度(20~70 ℃)范围内,SP-c-XG和XG溶液的流变曲线均为假塑型,符合Herschel-Bulkley模型;其屈服值、表观粘度和动力学模量随电解质质量分数增大均先下降后上升,而随pH值的升高先升高后降低,随温度升高而降低。 SP-c-XG和XG溶液具有相似的流变性,但与XG溶液相比,SP-c-XG溶液具有更高的屈服值和表观粘度,特别是具有更强的弹性和耐温性,在油田强化采油领域具有重要应用前景。     

铈改性Ru/HAP催化果糖一步法制备2,5-呋喃二甲酸

采用浸渍法制备稀土元素铈（Ce）改性的Ru/HAP催化剂Ce-Ru/HAP，以实现果糖一步法制备2，5-呋喃二甲酸（2，5-FDCA）。采用XRD、TEM、NH₃-TPD和XPS表征手段对催化剂的理化性质进行分析。结果表明，Ce很好地高度分散到载体HAP上，且并未对HAP的结构造成影响；Ce主要以Ce³⁺和Ce⁴⁺形式存在，前者的存在使催化剂表面产生大量氧空穴，同时两者之间的电子转移有利于氧空穴形成，提高储氧能力，提高催化剂的表面催化活性；催化剂具有丰富的弱酸位，能够抑制反应过程中副反应的发生。优化反应条件后，催化剂Ce（8%，质量分数）-Ru/HAP在温度160℃和氧气压力2 MPa的反应条件下，反应4 h时2，5-呋喃二甲酸的产率为34.2%。因此，Ce的引入能够提高传统贵金属复合型催化剂的催化活性，同时也为果糖一步制备2，5-FDCA提供新思路。     

顶空-气相色谱法测定聚碳酸酯聚合溶液中微量三乙胺

建立顶空-气相色谱法测定聚碳酸酯聚合溶液中三乙胺含量的快速测定方法。用乙醇将聚合溶液中的聚碳酸酯沉淀,滤液以二氯甲烷、乙醇、10%（质量分数）氢氧化钠溶液混合溶剂溶解定容,采用顶空-气相色谱法检测,色谱峰面积外标法定量。以DB-624柱（30 m×0.25 mm×1.4μm）为分离柱;载气为氮气,流量为1.2 mL/min;柱温升温程序：初始温度为80℃,以10℃/min的升温速率升至220℃;进样口温度为200℃;FID检测器温度为250℃;进样体积为0.6 mL;采用分流进样,分流比为20∶1。三乙胺质量浓度在0.2～2.0 mg/L范围内与色谱峰面积线性相关,相关系数为0.999 5,方法检出限为0.12 mg/L。样品加标回收率为98.47%～100.05%,测定结果的相对标准偏差为0.42%～1.34%(n=6)。该方法操作简单,适用于工业生产聚碳酸酯聚合溶液中三乙胺的批量快速检测。     

C12-s-C12•2Br和C12En混合水溶液的胶团化行为

季铵盐二聚表面活性剂C12 s C12•2Br（s=2、3、4、6）和非离子表面活性剂C12E10或C12E23在水溶液中生成混合胶团.其临界胶团总浓度cmcT值介于二元复配体系中各组分的临界胶团浓度和之间.当添加少量非离子型表面活性剂（在水溶液中的摩尔分数α2=0.1）时,混合胶团中C12E10或C12E23的摩尔分数均已超过0.35;随着溶液中非离子型表面活性剂含量的增大,混合胶团中逐渐以C12E10或C12E23成分为主.     

CoCl_2-PVA可逆热敏微胶囊的制备与性能

以低温可逆热敏示温材料氯化钴（CoCl2）为芯材、聚乙烯醇（PVA）为壳材、戊二醛（GA）为交联剂,在W/O/W混合乳液体系中,通过界面交联法制备了CoCl2-PVA可逆热敏示温微胶囊,并对其各项性能进行了系统研究。结果表明：当PVA溶液的质量分数为0.8%、PVA与GA摩尔比为1∶2.5、内水相pH为2、CoCl2溶...     

聚乙烯/氧化铝复合材料形态、流变和力学性能

将聚乙烯（PE）和氧化铝（AO）熔融共混制得综合性能更好的PE/AO复合材料。通过对其进行流变分析、热力学性能分析、力学性能分析、导热性能分析和断面微观结构分析,探究AO质量分数对复合材料结构及性能的影响。结果表明,随着AO质量分数的增加,复合材料逐步转为脆性材料,其弹性模量、屈服强度、导热系数、储能模量同步增加;当AO质量分数为10%时,复合材料的断裂强度为18.2 MPa,综合性能最好。     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.