甲基丙烯酸缩水甘油酯/苯乙烯固相接枝聚丙烯

以苯乙烯(St)为共单体，过氧化苯甲酰(BPO)为引发剂，采用固相接枝反应将甲基丙烯酸缩水甘油酯(GMA)接枝到聚丙烯(PP)大分子链上。研究了反应时间、单体用量、引发剂用量等因素对接枝率的影响。采用凝胶渗透色谱(GPE)测定了PP和接枝物PP-g-(GMA-St)的分子量和分子量分布。结果 表明固相接枝PP反应条件为[GMA／[St]=2，反应3．5h，加入GMA 10份，BPO 5份。St的加入有助于GMA与PP的接枝，同时在一定程度上抑制了PP的降解。     

在交联聚合物微球GMA/MMA表面接枝固载聚乙二醇的研究

以乙二醇二甲基丙烯酸酯为交联剂,采用悬浮聚合方法,制备了甲基丙烯酸缩水甘油酯(GMA)和甲基丙烯酸甲酯(MMA)的交联微球GMA/MMA.使用Lewis酸催化剂,通过环氧键的开环反应,将聚乙二醇(PEG)偶合接枝在交联微球GMA/MMA表面,实现了PEG的固载化,制得了三相相转移催化剂PEG-GMA/MMA.重点考察了各种因素对PEG接枝固载过程的影响,并研究了反应机理.实验结果表明,以交联微球GMA/MMA为载体,可以顺利地实现PEG的固载化,这是制备PEG三相相转移催化剂的简捷途径.实验发现,Lewis酸也能催化环氧键的开环反应,而且比质子酸的催化更加有效.溶剂的极性对偶合接枝反应的影响较大,采用极性大的溶剂有利于PEG的接枝固载.偶合接枝体系中,过高的催化剂用量会导致PEG双端羟基参与接枝反应,使载体表面大分子之间发生附加交联,不利于PEG的接枝固载.在适宜的反应条件下,接枝微球PEG-GMA/MMA表面的PEG接枝度可达0.20 g/g.     

可酶降解的温度及pH敏感水凝胶的制备及对牛血清白蛋白的吸附和释放

以4,4'-二甲基丙烯酰氨基偶氮苯(BMAAB)为偶氮交联剂,制备了可酶降解的N-异丙基丙烯酰胺(NIPAAm)-丙烯酸(AA)共聚物水凝胶. 结果表明,研究的凝胶均表现出在4 ℃和37 ℃之间的溶胀相转变. 以牛血清白蛋白(BSA)为模型药物,在pH=7.4的缓冲溶液中对BSA进行了负载. 结果表明,凝胶在4 ℃时对BSA的负载量为144.5 mg(BSA)/g(gel),37 ℃为14.8 mg(BSA)/g(gel). 凝胶在pH=7.4的缓冲溶液中,在结肠菌作用下能发生酶降解,药物累积释放量4 d可达100 mg(BSA)/g干胶.     

超亲水聚偏氟乙烯中空纤维膜的制备及性能

采用超声辅助接枝聚合技术, 将甲基丙烯酸缩水甘油酯(GMA)接枝到聚偏氟乙烯(PVDF)膜表面, 制备PVDF-g-GMA膜; 再利用氨基诱导环氧基团发生开环反应, 将苏氨酸(Thr)接枝到PVDF-g-GMA膜表面, 制备了具有两性离子结构表面的PVDF-g-GMA-Thr膜. 通过衰减全反射傅里叶变换红外光谱(ATR-FTIR)、 X射线光电子能谱(XPS)、 接触角测试仪、 场发射扫描电子显微镜(FESEM)和牛血清白蛋白(BSA)过滤实验等系统研究了改性前后PVDF膜表面的化学组成、 润湿性能、 表面形貌和抗污染性能. 研究结果表明, 随着PVDF-g-GMA接枝Thr反应时间的增加, PVDF-g-GMA-Thr膜的亲水性能明显提高, 接触角从90°降为0°, 呈现出超亲水性能. 同时PVDF-g-GMA-Thr膜的水通量明显提高, 当Thr诱导开环反应时间为12 h时, PVDF-g-GMA-Thr膜的水通量高达686 L/(m ²·h), 与PVDF原膜相比, 水通量提高了204.5%. 在BSA的过滤测试中, 与PVDF膜相比, PVDF-g-GMA-Thr膜呈现出良好的截留性能和抗污染性能, BSA截留率从42%提高到84%,水通量恢复率从53%提高到87%, 不可逆污染率从47%降到12%, 表明通过接枝Thr构筑两性离子结构表面可以有效减小膜污染.     

GMA和共单体对聚乙烯木塑复合材料的直接反应增容

通过甲基丙烯酸缩水甘油酯(GMA)、聚乙烯(PE)、木粉和其它助剂的熔融挤出,实现了GMA及GMA与共单体对PE和木粉的直接反应增容.通过扫描电镜(SEM)观测了PE基木塑复合材料(WPC)的冲击断面形貌.测试了WPC经抽提后所得木粉的傅立叶变换红外光谱(FTIR)和WPC的力学性能及热变形温度(HDT).研究了共单体苯乙烯(St)和抑交联剂亚磷酸三苯酯(TPP)对反应增容的影响.结果显示,经GMA和引发剂反应增容后,有部分PE分子键合到了木粉粒子上,从而增强了木塑两相的结合力;St的加入有利于提高GMA的接枝率,导致更多PE分子键合到了木粉粒子上,而TPP的加入则使GMA的接枝率有所下降.经GMA和引发剂直接反应增容后,WPC的力学性能和HDT均明显改善;St的加入有助于抑制PE的交联,但并未造成WPC力学性能和HDT的明显劣化;同时加入St和TPP后,WPC的HDT有所下降,而断裂伸长率和冲击强度则明显提高.     

瓜胶/聚丙烯酸互穿聚合物网络水凝胶对模型药物的负载与控制释放

考察了以牛乳清蛋白(BSA)为模型药物,通过相平衡分配法制备载药瓜胶(GG)/聚丙烯酸(PAA)互穿聚合物网络(IPN)水凝胶的工艺条件.借助紫外可见光谱仪研究了载药水凝胶在结肠酶存在下的控制释放行为.结果表明:载药容量(CM)随瓜胶、丙烯酸用量的增加而下降,半IPN水凝胶的Cm较全IPN的略大;结肠酶能明显提高半IPN与全IPN中的BSA释放速率,且提高幅度随GG含量的增加而加快,GG/PAA IPN水凝胶具有结肠定位降解的特性,有望成为靶向结肠给药的理想载体材料.     

受体吸附剂的制备、结构及对麻醉药物吸附的研究

在总结了阿片受体化学结构特征的基础上,合成了一系列以乙烯吡咯烷酮(Vp)、甲基丙烯酸缩水甘油酯(GMA)为单体与三烯丙基异氰尿酸酯(TAIC)为交联剂,在致孔剂存在下,进行三元悬浮共聚反应,制得大孔交联VGT共聚物.尔后经环氧开环反应及酯化反应,制备出具有类阿片受体化学结构的吸附剂,并初步研究了吸附剂对吗啡的吸附规律性.     

新型温敏羟丙基纤维素微凝胶的合成

天然高分子具有良好的生物相容性和生物可降解性,因此用天然高分子制备的微凝胶更适合于生物医学领域的应用。羟丙基纤维素(HPC)是一种具有温度敏感性的纤维素衍生物,可通过不同的方法制备为微凝胶,然而现有方法制备的HPC微凝胶都不能完全降解。我们采用一种新方法制备HPC微凝胶。首先通过NaIO4处理将醛基引入HPC。红外光谱检测证明了醛基的生成。氧化后的HPC仍具温敏性,其最低临界溶解温度(LCST)保持不变;当加热到LCST以上时,HPC分子通过疏水相互作用聚集成纳米小球;再加入交联剂己二酸二酰肼,通过醛基与胺基之间的反应,使纳米小球共价交联得到HPC微凝胶。电镜研究表明HPC微凝胶呈球形,粒径在100～300nm之间。浊度和光散射研究表明HPC微凝胶仍具温敏性。细胞毒性实验表明我们制备的微凝胶几乎没有细胞毒性。由于HPC及交联剂己二酸二酰肼均可生物降解,预期我们制备的微凝胶也能很好地降解,并有望应用于生物医学领域。     

多组分单体接枝聚丙烯/尼龙6反应共混物结晶行为研究

用多组分熔融接枝的方法将甲基丙烯酸缩水甘油酯 (GMA)和苯乙烯 (St)共同接枝到聚丙烯 (PP)上 ,制得具有较高GMA接枝率的多单体接枝聚丙烯 ,PP g (GMA co St) .将PP g (GMA co St)与尼龙 6 (PA6 )进行共混 ,利用扫描电镜 (SEM) ,差示扫描量热计 (DSC)和广角X射线衍射 (WAXD)对共混物的形态和结晶进行了研究 .在共混过程中 ,PP g (GMA co St)与PA6反应原位生成了PP g PA6 ,有效改善了共混物的相容性 ,分散相尺寸明显减小 .在PP g (GMA co St) PA6为 3 7的体系中 ,PP g (GMA co St)出现分级结晶现象 ,其在较低温度下的结晶属于均相成核结晶 .在PP g (GMA co St) PA6为 7 3的体系中 ,由于PA6相分散细微 ,在通常结晶温度下不结晶 ,而是在低温下均相成核与PP g (GMA co St)同时结晶 .WAXD证实体系中接枝PP ,PA6为分别结晶 ,无共晶或新的晶型产生     

生物碱分子表面印迹聚合物材料的设计与制备及其分子识别特性

采用巯基/偶氮二异丁腈(AIBN)表面引发体系,实现了甲基丙烯酸缩水甘油酯(GMA)在微米级硅胶微粒表面的引发接枝聚合,制得接枝微粒PGMA/SiO2;然后使接枝大分子PGMA的环氧基团与间二氨基苯磺酸钠(SAS)分子中的对位氨基发生开环反应,将苯磺酸钠基团键合在接枝大分子侧链,制得苯磺酸盐功能化的接枝微粒SAS-PGMA/SiO2。 在对功能微粒SAS-PGMA/SiO2与苦参碱分子间的相互作用进行考察研究的基础上,以戊二醛为交联剂,实施了苦参碱分子的表面印迹,制备了苦参碱分子表面印迹材料MIP-SASP/SiO2。 实验结果表明,在近中性溶液中,功能接枝微粒SAS-PGMA/SiO2与苦参碱分子间存在静电相互作用,以此为基础所设计与制备的表面印迹材料MIP-SASP/SiO2对苦参碱分子具有特异的识别选择性与优良的结合亲和性。 相对于对照物金雀化碱而言,该印迹材料对苦参碱的识别选择性系数为10.7。     

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.     

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.     

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.     

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.     

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.     

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.