环己烷液相亚硝化一步合成己内酰胺

采用正交设计试验法对乙酸锰催化环己烷液相亚硝化一步合成己内酰胺的新反应进行了研究.考察了反应温度、反应时间、催化剂用量和反应物配比等因素对环己烷转化率和己内酰胺选择性的影响.结果表明,最佳的合成条件为:在81℃反应36 h,催化剂乙酸锰用量为环己烷质量的2.5%,亚硝基硫酸与发烟硫酸的质量比为1:3.在此优化的条件下,环己烷液相亚硝化反应的转化率为8.12%,目标产物己内酰胺的选择性达10.54%.     

磁性碳基磺酸化固体酸催化剂的制备及其催化水解纤维素

以纤维素和硝酸铁为原料,发烟硫酸为磺酸化试剂,采用热解法合成了磁性碳基磺酸化固体酸催化剂(Fe/C-SO3H).利用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、傅里叶变换红外(FT-IR)光谱仪和振动样品磁强计(VSM)等手段对催化剂进行了表征,评价了催化剂在纤维素水解反应中的催化活性.结果表明,Fe是以γ-Fe2O3的形式存在于碳本体中,催化剂呈现超顺磁性.对于纤维素的水解反应,在优化条件下,纤维素的转化率可达40.6%.此外,催化剂可稳定分散于反应体系中,并在外加磁场作用下可快速与反应体系分离.但催化剂重复使用时催化活性有所下降,其失活原因经初步认定是由于表面部分磺酸基团在反应过程中脱落.     

窄分子量分布聚四氢呋喃的合成

以发烟硫酸-高氯酸为催化剂,通过四氢呋喃的阳离子开环聚合合成了窄分子量分布的聚四氢呋喃(PTHF)。研究了发烟硫酸和高氯酸用量、反应时间、反应温度等对PTHF分子量(Mn)及其分布(Mw/Mn)的影响。结果表明,减少发烟硫酸或增加高氯酸用量可使Mn上升;反应时间超过3 h后,反应时间对Mn及Mw/Mn的影响不大;于2℃反应Mn有最大值(11 760);反应时间5 h,在N2中聚合的Mw/Mn较小;低转化率(Mw/Mn小于1.2)时,通N2对Mn(4 000~5 500)及Mw/Mn(1.12~1.19)的影响不大。     

羟基功能化离子液体的绿色合成及电化学性能

以1-甲基咪唑、3-氯-环氧丙烷和四氟硼酸为原料,在30℃和超声波辅助作用下,合成了羟基功能化离子液体1-(3-氯-2-羟基丙基)-3-甲基咪唑四氟硼酸盐(CHPMIM.BF4)和1,3-二-(1-甲基咪唑基)-2-丙醇四氟硼酸盐盐酸盐(DMIMP.BF4.Cl),该方法大大缩短了反应时间,避免了无机盐的生成。它们的电化学稳定性和离子电导率测定结果表明,CHPMIM.BF4和DMIMP.BF4.Cl具有较好的电化学稳定性,电化学稳定窗口分别为4.6 V和4.7 V;但前者的离子导电率要远远小于后者,25℃时它们的电导率分别为0.26mS/cm和9.86mS/cm。     

N,N-二甲氨基磺酰氯合成工艺的优化

以磺酰氯和二甲胺盐酸盐为原料在三乙胺催化剂的作用下合成N,N-二甲氨基磺酰氯,并进行了单因素实验,在此基础上运用响应面法对N,N-二甲氨基磺酰氯合成工艺进行了优化,优化调整后的工艺条件为:反应温度9℃,二氯乙烷用量250 mL,n(二甲胺盐酸盐):n(磺酰氯)=1.0:1.2.在该工艺条件下重复实验,N,N-二甲氨基磺...     

7-(8-羟基-3, 6-二磺基萘偶氮)-8-羟基喹啉-5-磺酸催化荧光测定痕量铜

建立了试剂7-(8-羟基-3, 6-二磺基萘偶氮)-8-羟基喹啉-5-磺酸催化荧光法测定痕量铜的新方法。采用多目标单纯形优化理论获得最佳实验条件: 0.05%试剂 1.3mL, 0.1mol/L NaOH 6.2ml, 0.1%KIO4 1.6mL, 反应时间15min。对反应机理作了详细探讨与研究, 方法用于水样、铸造铝合金样中痕量铜的测定, 结果令人满意。     

N-[4-(磺酰胺)苯基](甲基)丙烯酰胺的合成

以对氨基苯磺酰胺、丙烯酰氯(或甲基丙烯酰氯)为原料合成了N-[4-(磺酰胺)苯基]丙烯酰胺(ASPAA)和N-[4-(磺酰胺)苯基]甲基丙烯酰胺(ASPMAA),其结构经^1H NMR,IR和元素分析表征。合成ASPAA的最佳条件：对氨基苯磺酰胺13．76g(80mmol),n(对氨基苯磺酰胺)：n(丙烯酰氯)=1．0：1．1,n(丙烯酰氯)：n(NaHCO3)：1．00：1．14,0℃～2℃反应3h,反应液倾入10倍体积的的甲醇-水[V(甲醇)：V(水)=1：10]中析出产物,收率在60％以上。合成ASPMAA的最佳条件：对氨基苯磺酰胺6．88g(40mmol),n(对氨基苯磺酰胺)：n(甲基丙烯酰氯)=1.00：1．05,n(三己胺)：n(甲基丙烯酰氯)：1．0：1．0,在0℃～2℃滴加甲基丙烯酰氯后先在室温下反应1h,然后在60℃反应1h,反应液倾入700mL石油醚中析出产物,收率50％～60％．     

树状PAMAM桥联受阻酚的合成与表征

以β-(3,5-二叔丁基-4-羟基苯基)丙酰氯(简称3,5-丙酰氯)为原料,以1.0G聚酰胺-胺(PAMAM)为桥联基,通过酰胺化反应合成2种含有4个受阻酚单元的树状PAMAM桥联受阻酚.通过条件优化实验确定最佳反应条件:n(3,5-丙酰氯)∶n(PAMAM)=6∶1;K2CO3为促进剂;苯和水为反应混合溶剂,其中苯用量为40mL,水用量为9.7mL;反应时间15h;反应温度为25℃,此条件下可以得到纯度较高的2种树状PAMAM桥联受阻酚.红外光谱、核磁共振及质谱分析表明,合成的分子与目标分子结构完全相符.     

羟丙基壳聚糖的制备

用环氧丙烷改性壳聚糖得羟丙基壳聚糖 ,确定制备的最佳条件为 :壳聚糖 2 .5 g,环氧丙烷 3 0mL ,反应时间 4h,反应温度 60℃～ 70℃。所得羟丙基壳聚糖的特性粘度可低至 2 5mL·g-1,3 0℃溶解度为 7g·(H2 O1 0 0mL) -1。     

多目标单纯形法在茜素红催化荧光测定痕量钒(V)中的应用

本文建立了茜素红催化荧光测定痕量钒(V)的新方法.在λ_(ex)/λ_(em)=381/445(nm),由多目标罚函数单纯形法获得最佳实验条件为:1%茜素红6mL,1mol/L盐酸2.1mL,饱和KIO_4,1.8mL,反应温度85℃,反应时间15.30min,钒的检测下限为7×10~(-10)g/mL,反应对试剂及金属离子均为一级反应.方法用于水样和铬钒钢中钒的测定,结果满意.     

Effect of polyethylene glycol on sulfonated polyether imide (SPEI) for fuel cell applications

The sulfonated polyetherimide (sPEI) was synthesized by direct sulfonation method using chlorosulfonic acid as a sulfonating agent. Different sulfonation degrees of sPEI was obtained by varying the ratio of PEI to chlorosulfonic acid and reaction time. Then, sulfonated polyetherimide was blended with polyethylene glycol (PEG) and thermally cross-linked in order to achieve high performance proton exchange membrane. It was found that the addition of PEG resulted in a significant increase in porosity and water uptake of the membranes, which favored proton transport at low temperature. The maximum proton conductivity was 11 mS/cm at 75°C for the blend membrane containing 20% PEG. The sulfonation and blend modification of PEI were characterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy.     

Synthesis and characterization of bisulfonated poly(vinyl alcohol)/graphene oxide composite membranes with improved proton exchange capabilities

Composite membranes based on poly(vinyl alcohol) (PVA) and graphene oxide (GO) were prepared by solution-casting method to be used as proton exchange membranes (PEMs) in fuel cell (FC) applications. Bisulfonation was employed as a strategy to enhance the proton conductivity of these membranes. First, a direct sulfonation of the polymer matrix was accomplished by intra-sulfonation of the polymer matrix with propane sultone, followed by the inter-sulfonation of the polymer chains using sulfosuccinic acid (SSA) as a crosslinking agent. Furthermore, the addition of graphene oxide (GO) as inorganic filler was also evaluated to enhance the proton-conducting of the composite membranes. These membranes were fully characterized by scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and tensile tests. Besides, the proton conductivity of these membranes in a fully hydrated state was also analyzed by electrochemical impedance spectroscopy (EIS). The effect of the intra- and inter-sulfonation of the polymer matrix on the structural, morphological, thermal and mechanical properties of the membranes were determined. Increasing the density of sulfonic acid groups in the membranes resulted in a trade-off between a better proton conductivity (improving from 0.26 to 1.00 mS/cm) and a decreased thermal and mechanical stability. In contrast, the incorporation of GO nanoparticles into the polymer matrix improved the thermal and mechanical stability of both bisulfonated composite membranes. The proton conductivity appreciably increased by the combination of bisulfonation and introduction of GO nanoparticles into the polymer matrix. The sPVA/30SSA/GO composite membrane exhibited a proton conductivity of 1.95 mS/cm at 25 °C. The combination of the GO nanoparticles with the chemical bisulfonation approach of PVA allows thus assembling promising proton exchange membrane candidates for fuel cell applications.     

Preparation and Conducting Behavior of Amphibious Organic/Inorganic Hybrid Proton Exchange Membranes Based on Benzyltetrazole

A series of novel amphibious organic/inorganic hybrid proton exchange membranes with H3PO4 doped which could be used under both wet and dry conditions was prepared through a sol-gel process based on ac...     

Synthesis and characterization of sulfonated naphthalenic polyimides based on 4,4′-diaminodiphenylether-2,2′-disulfonic acid and bis[4-(4-aminophenoxy)phenylhexafluoropropane] for fuel cell applications

The paper describes the synthesis and characterization of sulfonated polyimides based on 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTDA), 4,4′-diaminodiphenylether-2,2′-disulfonic acid (ODADS) and (bis[4-(4-aminophenoxy)phenylhexafluoropropane] (BDAF)). Several copolymer samples were prepared by varying the molar ratio of ODADS: BDAF (0.5:1.50, 0.75:1.25, 1:1 and 1.50: 0.5) in the initial monomer feed. Structural characterization of the copolymers was done using FT-IR and ¹H NMR. ¹H NMR was also used to calculate the copolymer composition. Thermal characterization was done using thermogravimertry and dynamic mechanical analysis. Polymer films were prepared by solution casting using m-cresol as solvent. The membranes thus prepared were characterized for water uptake, water stability, methanol permeability and proton conductivity. The obtained sulfonated polyimides (SPI’s) had proton conductivities in the range of 0.137-3.94 mS/cm. SPI’s with 50% degree of sulfonation had proton conductivity comparable to that of Nafion with methanol permeability lower than that of Nafion. It was found that the degree of sulfonation of polyimide had a large effect on the thermal stability, water uptake, ion-exchange capacity and proton conductivity.     

Electrical Properties of NASICON-type Structured Li1.3Al0.3Ti1.7(PO4)3 Solid Electrolyte Prepared by 1,2-Propylene glycol-assisted Sol-gel Method

Lithium-ion conductor Li_1.3Al_0.3Ti_1.7(PO₄)₃ with an ultrapure NASICON-type phase is syn-thesized by a 1,2-propylene glycol (1,2-PG)-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec-tron microscopy, electrochemical impedance spectroscopy, and chronoamperometry test.Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu-tion is obtained without the precipitation of Ti⁴⁺ and Al³⁺ with PO₄^3-. Well crystallizedLi_1.3Al_0.3Ti_1.7(PO₄)₃ can be prepared at much lower temperatures from 850 oC to 950 oC within a shorter synthesis time compared with that prepared at a temperature above 1000 oC by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 oC with an activation energy as low as 36.6 kJ/mol for the specimen pre-sintered at 700 oC and sintered at 850 oC. The high conductivity, good chemi-cal stability and easy fabrication of the Li_1.3Al_0.3Ti_1.7(PO₄)₃ provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.     

Synthesis and performance study of a novel sulfonated polytriazole proton exchange membrane

Sulfonated polytriazole (SPTA) proton exchange membranes (PEMs) with a series of sulfonation degrees was synthesized based on click chemistry from a rigid diazide monomer, 4,4′-bis(azidomethyl)-1,1′-biphenyl (BAMB), with 2,2-bis[(4-propargyloxy)phenyl]propane (BPBPA) and 4,4′-diazido-2,2′-stilbenedisulfonic acid disodium salt (DSDA). The structure of the copolymers was characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). As a result of the introduction of rigid biphenyl structure and the ionic interaction between triazole rings and sulfonic acid groups, the SPTA membranes exhibited higher water uptake and lower swelling ratio compared to NRE211 membrane, indicating excellent dimensional stability. AC impedance revealed that the proton conductivity of SPTA membranes ranged from 2.5 to 35 mS/cm at 30 °C and 13–105 mS/cm at 80 °C. Besides, the membranes have high thermal and oxidative stability, good mechanical property, and low methanol permeability as well.     

Direct electro-deposition of graphene from aqueous suspensions

We describe the direct electro-chemical reduction of graphene oxide to graphene from aqueous suspension by applying reduction voltages exceeding -1.0 to -1.2 V. The conductivity of the deposition medium is of crucial importance and only values between 4-25 mS cm(-1) result in deposition. Above 25 mS cm(-1) the suspension de-stabilises while conductivities below 4 mS cm(-1) do not show a measurable deposition rate. Furthermore, we show that deposition can be carried out over a wide pH region ranging from 1.5 to 12.5. The electro-deposition process is characterised in terms of electro-chemical methods including cyclic voltammetry, quartz crystal microbalance, impedance spectroscopy, constant amperometry and potentiometric titrations, while the deposits are analysed via Raman spectroscopy, infra-red spectroscopy, X-ray photoelectron spectroscopy and X-ray diffractometry. The determined oxygen contents are similar to those of chemically reduced graphene oxide, and the conductivity of the deposits was found to be ～20 S cm(-1).     

Synthesis of sulfonated aromatic poly(ether amide)s and their application to proton exchange membrane fuel cells

A series of wholly aromatic sulfonated poly(ether amide)s (SPEAs) containing a sulfonic acid group on the dicarbonyl aromatic ring were prepared via a polycondensation reaction of sulfonated terephthalic acid (STA), terephthalic acid (TA), and aromatic diamine monomers. The degree of sulfonation was readily controlled by adjusting the monomer feed ratio of STA and TA in the polymerization process, and randomly sulfonated polymers with an ion exchange capacity (IEC) of 1.0–1.8 mequiv/g were prepared using this protocol. The chemical structures of randomly sulfonated polymers were characterized using NMR and FT‐IR spectroscopies. Gel permeation chromatography analysis of SPEAs indicated the formation of high‐molecular‐weight sulfonated polymer. Tough and flexible SPEA membranes were obtained from solution of N,N‐dimethylacetamide, and thermogravimetric analysis of these membranes showed a high degree of thermal stability. Compared with previously reported sulfonated aromatic polyamides, these new SPEAs showed a significantly lower water uptake of 10–30%. In proton conductivity measurements, ODA‐SPEA‐70 (IEC = 1.80 mequiv/g), which was obtained from polycondensation of 4,4′‐oxydianiline and 70 mol % STA, showed a comparable proton conductivity (105 mS/cm) to that of Nafion 117 at 80 °C. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 485–496, 2009     

Kinetic study of the sulfonation of hydrogenated styrene butadiene block copolymer (HSBS): Microstructural and electrical characterizations

In this work homogeneous sulfonation kinetic and both, microstructural and electrical characterizations of hydrogenated styrene butadiene block copolymer (HSBS) were studied. The incorporation of sulfonic groups was checked by infrared spectroscopy (FTIR-ATR) and the sulfonation level was determined by both, elemental analysis (E.A.) and chemical titration. Thermal behavior was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), in order to determine thermal transitions and stability, respectively. Microstructure was studied, by means of dynamic mechanical analysis (DMA). Atomic force microscopy (AFM) was studied for several samples and evidenced a morphology change when the sulfonation level increases. Finally, electrical behavior was recorded by means of electrochemical impedance spectroscopy (EIS) and the four-probe technique (FPT). Results show that sulfonation of the benzene rings, in the styrene units, has effectively occurred and that the sulfonation level increases with reaction time. When incrementing the sulfonation level, a structural change in the copolymer was observed. Interconnected clusters allow proton conduction through the membrane. The ion conductivity obtained was about 10⁻² S/cm.     

不同磺化度下的磺化聚醚醚酮对全钒储能液流电池性质影响的研究

本文报道了采用浓硫酸作为磺化剂,成功合成了不同磺化度下的聚醚醚酮(PEEK)膜,并深入研究了磺化条件包括磺化时间和磺化剂的用量对所获薄膜性能的影响,获得了在不同磺化度（DS）下SPPEK膜的离子交换容,含水率,机械性能,质子电导率等参数,特别测定了在全钒液流电池工作条件下钒离子(Ⅳ)渗透率,首次为该类液流储能电池使用价廉质优的质子交换膜提供了基础实验数据。室温条件下的实验结果如下：1）磺化12小时后,膜的磺化度46%,含水量为28%,钒离子(Ⅳ)选择性最佳（钒离子渗透率为1.2×10-7 cm2/min-1,是Nafion117 (2.9×10-6 cm2/min-1)的1/24）,其质子电导率只有0.02 S/cm;2）磺化96小时其磺化度达79%的膜,质子电导率达0.16 S/cm,是Nafion117 (0.10S/cm) 的1.6倍, 但其机械性能最差;3）与Nafion117膜相比,磺化在36到48小时的SPPEK膜其机械力学性能好,薄膜的钒离子渗透率、离子交换容IEC、质子导电率和含水率高,且对钒离子的选择性佳,尤其价格仅为Nafion膜的1/13,是理想的Nafion膜的代替物,可望直接应用于全钒氧化还原液流（VRB）电池中。本文还讨论了磺化时间和不同磺化剂量对膜的性质的影响。