磺化聚苯醚离聚体的合成及溶液性质研究

合成一系列磺化度的磺化PPO(S-PPO),以磺化度为20.9mol％的S-PPO的钠盐和锂盐为代表,研究其在四氢呋喃/甲醇混合溶剂中的离聚体行为。结果表明,S-PPO离聚体在溶液中的链聚集状态与聚合物浓度、反离子半径和温度密切相关。     

磺化丁基橡胶离聚体在混合溶剂中的聚集行为

用顺磁共振（ESR）谱和粘度法考察了磺化丁基橡胶离聚体在二甲苯／正己醇混合溶剂中的聚集行为．ESR谱表明离聚体的离子基团发生聚集，其聚集程度受极性共溶剂（正己醇）的影响．粘度考察表明，在不同的浓度时离子基团有不同的聚集形式，低浓度时以分子内聚集为主，高浓度时以分子间聚集为主．离聚体的聚集度（DA）与浓度（c）的关系可用经验式DA＝Aexp（kc2）表示，其中A、k为常数．k值反映聚集度受浓度影响的程度，醇含量增大时k值减小，这是因为醇对离子的溶剂化作用导致离子聚集的倾向减小．     

PBMA-b-PSt磺化嵌段离聚体在DMF溶液中的聚集行为

采用激基缔合物荧光光谱法研究了轻度磺化聚甲基丙烯酸丁酯－b－聚苯乙烯（PBMA-b－PSt）嵌段离聚体在极性溶剂N，N－二甲基甲酰胺（DMF）溶液中的聚集行为；发现嵌段离聚体的磺化度和浓度强烈影响溶液中聚合物链的聚集态结构，不同的磺化度样品具有不同的临界聚集浓度；随磺化度增加，聚合物链缠绕密集，形成具有多苯环的聚集体，而且当磺化度为摩尔分数x＝3．59％时，荧光发射光谱最大发射峰波长出现最大红移，临界聚集浓度最低，说明最容易形成多苯环聚集体，该磺化点可以认为是磺化聚甲基丙烯酸丁酯－b－聚苯乙烯体现离聚体行为和聚电解质行为的临界磺化度。     

磺化丁基橡胶离聚体在溶液中的聚集行为(Ⅰ)──ESR谱研究

用ESR谱考察了磺化丁基橡胶锰盐(Mn-SIIR)离聚体在二甲苯/醇(少量)混合溶剂中的离子聚集行为。结果表明,在所考察的范围内,浓度及磺化度增大时ESR谱的形状变化不大,这反映了离子聚集程度并没有发生明显变化;另外,极性共溶剂(醇)增多时,谱线分辨度增大,反映了离子聚集程度下降;温度升高时谱线变模糊,反映离子聚集程度增大。这些结果有力地支持了Lundberg等人提出的离聚体溶液粘度变化平衡式。     

轻度磺化聚苯乙烯与聚苯乙烯共混物的流变性能表征

采用DSR-200动态应力流变仪研究了磺化度为0.98%(摩尔分数)的轻度磺化聚苯乙烯(SPS)离聚物及其锌盐(ZnSPS)与聚苯乙烯(PS)的共混物(PS/SPS,PS/ZnSPS)的流变性能.由于离聚物中离子聚集的物理交联作用,使其流变性能与PS相比有明显差别.动态频率实验结果表明,所有样品均可采用时温等效处理.另外,在与分子链运动相关的低频区,由于离子聚集的作用使得离聚物的模量远大于PS的模量.离聚物在稳态剪切作用下,由于离子聚集的破坏而表现出明显的屈服现象,并能用Utracki的屈服应力公式表征其屈服应力和零切粘度.此外,离聚物的屈服现象还与温度相关.由于动态和稳态实验分别测试离子聚集存在和破坏的不同材料状态,因此对离聚物无法应用Cox-Merz规则.动态和稳态实验结果均表明,PS/SPS和PS/ZnSPS的性能与组成的变化规律不同,意味着二者之间存在不同的离子聚集结构或相互作用.     

3,4-聚异戊二烯的磺化反应及其离聚体的结构研究

本工作合成了磺化的3,4-聚异戊二烯及其离子聚合体,IR和NMR谱图证明对3,4-聚异戊二烯的磺化反应是成功的,并且磺酸基团主要与3,4-链节的侧基双键发生反应。WAXD对磺化3,4-聚异戊二烯及其离聚体的研究表明,磺化度的增加使离聚体的结晶能力降低,SAXS结果表明,在离子含量为3.29mol％的离聚体中,未观察到离子簇聚集,只观察到多重离子对的散射。     

碘化丁基橡胶离聚体在溶液中的聚集行为（I）：ESR谱研究

用ＥＳＲ谱考察了磺化丁基橡胶锰盐（Ｍｎ－ＳＩＩＲ）离聚体在二甲苯／醇（少量）混合溶剂中的离子聚集行为。结果表明，在所考察的范围内，浓度及磺化度增大时ＥＳＲ谱的形状变不大，这反映了离子聚集程度并没有发生明显变化，另外，极性共溶剂（醇）增多时，线分辨度增大，反映了离子聚庥程度下降；温度升高时谱线变模糊，反映了离子聚集程度增大，这些结果有力地支持了Ｌｕｎｄｂｅｒｇ等人提出的离聚体溶液粘度变化平衡式。     

溶剂极性对聚苯醚离聚体微乳液相反转影响的研究

以乙酰磺酸为磺化剂制备了磺化度为 3%～ 1 7% (摩尔比 )的磺化聚苯醚 (SPPO)。在一定的温度和搅拌速度下 ,加水将SPPO离聚体溶液乳化成水包油的稳定水基微乳液。用电导率、粘度、表面张力等表征了SPPO离聚体溶液在微乳化过程中的相反转 ,研究了溶剂的极性对SPPO微乳化过程相反转的影响。     

乙丙三元共聚物磺酸锰离聚体溶液中离子的相互作用

乙丙三元共聚物(EPDM)磺酸盐离聚体在二甲苯/正己醇中具有特异的粘度-浓度及粘度-温度关系,前文用波谱方法考察了离聚体溶液中的离子相互作用。本文以含Mn~(2+)(核自旋数5/2)的EPDM磺酸盐(SEPDM-Mn)为对象,且与Mg盐(SEPDM-Mg)离聚体比较,讨论了比浓粘度与溶液浓度及温度的关系,用FTIR和ESR方法对离聚体溶液作进一步考察,发现     

FTIR和ESR法研究离聚体溶液中的离子相互作用

磺化乙丙三元共聚物(SEPDM)离聚体在二甲苯/5％正己醇混合溶剂中具有特异的粘浓关系和粘温关系,估计是由于金属离子被己醇溶剂化而影响离子间相互作用引起的,但尚未有更多的实验数据加以验证.本文用FTIR和ESR方法对SEPDM离聚体溶液作进一步考察,发现金属离子与己醇确实存在溶剂化效应,溶剂化程度与离子的大小、浓度和温度有关,它直接影响离子在溶液中存在的状态(单离子或离子聚集体),这些结果为从分子水平了解离聚体溶液性质提供了理论根据.用波谱方法研究离聚体溶液中的离子相互作用尚鲜见报道.     

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.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

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.