葡萄糖对聚偏氟乙烯膜的共混改性研究

以葡萄糖为共混剂,聚乙烯吡咯烷酮为添加剂,用相转化法获得了聚偏氟乙烯/葡萄糖共混膜。研究了聚偏氟乙烯浓度,葡萄糖与偏氟乙烯的共混比例和添加剂含量等各项制膜条件对微孔膜的结构和性能的影响。结果显示当聚偏氟乙烯的固含量为10wt%,葡萄糖含量为4wt%,聚乙烯吡咯烷酮为固含量的2wt%,溶液蒸发时间为30min时,能够得到性能理想的微孔膜。     

PVDF／PAN共混超滤膜

ＰＶＤＦ／ＰＡＮ共混超滤膜尹秀丽＊宋艳秋（天津纺织工学院材料科学系天津３００１６０）关键词聚偏氟乙烯，聚丙烯腈，共混，超滤膜１９９６－１１－２０收稿，１９９７－０５－０７修回共混是改变高分子材料性能的重要手段，已发现用聚合物共混的方法能制得性能优异的...     

光波导乙醇气体传感器的研究

以聚偏氟乙烯(PVDF)作为敏感试剂固定在钾(K⁺)离子交换玻璃光波导表面,研制了光波导乙醇气体传感器.该传感器具有可逆性好、灵敏度高、响应速度快、选择性和重现性好、能在室温操作等特点.     

碳纳米管对聚偏氟乙烯膜的共混改性研究

用相转化法制备了聚偏氟乙烯/碳纳米管共混膜,研究了共混膜的表面结构、水通量、孔隙率、接触角和机械性能。结果显示碳纳米管的加入提高了聚偏氟乙烯膜的亲水性和水通量,当聚偏氟乙烯浓度为10wt.%,碳纳米管含量为1.5wt.%时,共混膜的水通量和孔隙率最高,从243 L/m2·h和86.2%提高到365 L/m2·h和91.4%;接触角也由82°减小为67°;同时,共混膜的机械性能也得到显著提高。     

聚偏氟乙烯膜三维离子传输通道的构建及其在全钒液流电池中的性能研究

随着新能源技术的不断发展, 大规模储能技术受到了广泛的关注. 全钒液流电池因其容量和功率设计灵活、安全可靠、寿命长等优势成为发展较快的储能电池之一. 离子膜作为液流电池的关键部件, 对电池的能量转化效率、寿命和成本具有显著影响. 本工作以高化学稳定性的聚偏氟乙烯作为膜材料, 利用聚乙二醇和聚乙烯吡咯烷酮分别作为模板和稳定剂, 在聚偏氟乙烯膜内成功构建了具有较好H/V离子选择性的三维离子传输通道. 电池性能测试表明, 该聚偏氟乙烯(PVDF)离子膜有着出色的化学稳定性, 在100 mA•cm^-2电流密度下, 具有98%以上的电流效率和83.5%的能量效率. 此外, 聚偏氟乙烯具有价格低的显著特点, 使其在全钒液流电池中有较好的应用前景.     

含氟聚合物杂化电解质膜的结构分析

聚偏氟乙烯;共聚物;微孔膜;离子电导率;含氟聚合物杂化电解质膜的结构分析     

超亲水-水下超疏油PVDF-g-PAA多孔膜的制备及油水分离性能

采用相反转方法制备了丙烯酸(AA)接枝的超亲水-水下超疏油聚偏氟乙烯膜(PVDF-g-PAA),通过加入一定量的聚乙烯吡咯烷酮获得可用于油水分离的多孔聚偏氟乙烯膜.多孔聚偏氟乙烯膜具有较好的抗油污染性能及较高的力学强度,可以快速高效地分离油水混合体系和乳化油水体系,分离性质稳定,多次使用后对油水混合物的分离效率在98%以上,对油水乳化液的分离效率在91%以上,可广泛应用于油水混合体系和乳化油水体系的油水分离.     

聚1-三甲基硅基丙炔膜渗透汽化分离乙醇-水溶液的研究Ⅰ.PTMSP膜渗透汽化分离乙醇-水传质的基本特征

研究了聚１－三甲基硅基丙炔膜渗透汽化分离乙醇－水溶液传质的主要特点。发现膜对乙醇优先吸附、溶解，对水优先扩散。但因吸附液中水含量很低，总的结果表现为优先透醇。在３１３Ｋ，膜厚２０～２５μｍ，料液浓度１０ｗｔ％时，α＝１８．５，Ｊ＝０．９６９ｋｇ·ｍ－２·ｈ－１。透过膜的渗透液及其中的水和乙醇渗透汽化表观活化能分别为２８．８７、３１．３０和２７．６６ｋＪ／ｍｏｌ，并随料液浓度下降而增加。对实验数据进行非线性回归，建立了该膜传递乙醇的经验关联式：Ｊｅ＝－５．５６４Ｃ２Ｅ０＋１３．３４ＣＥ０－０．１５７３（ｋｇ·ｍ－２·ｈ－１），计算值与实验值相吻合。     

儿茶酚在预活化聚酰胺膜多酚氧化酶电流传感器上的响应特性

本采用预活化聚酰膜固定多酚氧化酶并与浸蜡石墨极组合成传感器，测定儿茶酚的线范围２．×１０－７－１．２５×１０＾－５ｍｏｌ／Ｌ。检出限１．５×１０＾－７ｍｏｌ／Ｌ。酶的固定时间仅需１－２ｍｉｎ，５个月之后被固定酶的活性未见下降，活性酶膜的制备，贮存，替换均很方便，对传感器的机理进行了探讨。     

偏氟乙烯的聚合反应

本文研究了用有机引发剂引发偏氟乙烯的水相聚合,并对制得的聚偏氟乙烯的性质进行了研究。有机引发剂引发聚合的聚偏氟乙烯的热稳定性、强度、结晶度和熔点均比用过硫酸盐引发聚合的聚偏氟乙烯高。     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.