Effect of organic acid on lauroamide propyl betaine surface dilatational modulus and foam performance in a porous medium

The purpose of this work was to study the effect of surface tension and surface dilatational modulus on foam performance in high-salinity water in a porous medium. In order to clarify the role of the surface dilatational property in foam flow in a porous medium, three systems were established: a system with low surface dilatational modulus and high surface tension, a system with low surface dilatational modulus and low surface tension, and a system with high surface dilatational modulus and low surface tension. Measurement of dilatational modulus and surface tension showed that lauroamide propyl betaine (LAB) could not reduce surface tension and that surface dilatational modulus was low. The addition of lauric acid (LCOOH) to LAB could not achieve high surface dilatational modulus; however, it could reach lower surface tension. The addition of myristic acid (MCOOH) to LAB could achieve high surface dilatational modulus and lower surface tension. Unlike the other two systems, the results of a dilatational modulus comprised of a mixture of MCOOH and LAB were not a constant, as demonstrated by varied surface area deformation outcomes. With the increase of deformation, surface dilatational modulus decreased. Results of foam flow tests showed that among the two lower surface dilatational modulus systems, LAB foam had higher flow resistance regardless of flow rate. Among the two systems of similar lower surface tension, the mixture of LAB and MCOOH showed higher flow resistance than the mixture of LAB and LCOOH. However, with the increase of flow rate, pressure differences between the two systems became smaller, which corresponded to the decrease of surface dilatational modulus with an increase of deformation.     

Hollow porous organic polymer: High‐performance adsorption for organic dye in aqueous solution

Several hollow porous organic polymers were conveniently fabricated by poly‐condensation of tetraphenyl porphyrin (TPP), tetrabiphenyl porphyrin (TBPP), or triphenylbenzene (TPB), with nano‐sized ZnO particles as template and AlCl₃ as catalyst. The hollow polymers exhibit much enhanced adsorption capacity for organic dyes in aqueous solution relative to the pristine polymers. Particularly, the hollow polymer based on TBPP (h‐COP‐P) displays high adsorption capacity (460 mg/g within 500 min) as well as good recycling performance toward Rhodamine B. This capacity is about three times larger than that of corresponding pristine POPs (COP‐P) and is even comparable with the best performed organic polymers reports to date, which is ascribed to its unique hydrophobic hollow structure. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1329–1337     

A hexaazatriphenylene-based porous organic polymer for high performance supercapacitor

Porous organic polymers (POPs) with high physiochemical stability and pseudocapacitive activity are crucial for supercapacitors with high specific capacitance and long cycle life. We report herein a hexaazatrinaphthylene-based POP (HPOP-1) for high-performance supercapacitor by introducing redox-active hexaazatrinaphthylene (HATN) moiety through Sonogashira–Hagihara coupling reaction. HATN moiety can undergo a proton-induced electron transfer redox reaction, which endows HPOP-1 with high pseudocapacitive activity. As electrode materials for supercapacitor application, HPOP-1 exhibits high specific capacitance (667 F g⁻¹ at 0.5 A g⁻¹) and long-term cyclic stability (90% capacitance retention after 10,000 cycles at 5 A g⁻¹) in a three-electrode system with 1 M H₂SO₄ as the electrolyte. In addition, HPOP-1 also exhibits a specific capacitance of 376 F g⁻¹ at 0.5 A g⁻¹ in 1 M KOH electrolyte. An asymmetric supercapacitor was further fabricated with HPOP-1 as negative electrode and rGO as positive electrode, respectively. The device delivers a specific capacitance of 63 F g⁻¹ at 0.5 A g⁻¹ and a rate performance of 37 F g⁻¹ at 5 A g⁻¹. Our work provides a facile approach for the design and preparation of pseudocapacitive POPs with high specific capacitance and long cycle life.     

外缘烷基链长对共轭有机小分子聚集行为及光电性质影响

改变分子化学结构和调控分子结构聚集态行为从而影响或改变材料的化学和物理性质, 是开发新型高效有机光电功能材料的重要手段. 在共轭有机分子外缘引入烷基链一般是为了改进材料溶解性能, 但近来的一些研究表明, 烷基链长对一些共轭有机小分子固态聚集行为和光电性质具有重要影响, 烷基链扮演着显著调控材料光电性质的“功能基团”作用. 本文以聚集诱导发光（aggregation-induced emission, AIE）/聚集强化荧光（aggregation enhanced emission, AEE）发射共轭有机小分子为重点, 对近年来有关烷基链长对共轭有机分子聚集形态和光电性质影响的一些典型事例进行评述, 旨在使人们在进行共轭有机分子设计合成及其结构与性能关系研究中能够关注烷基链的因素, 使烷基链变化作为功能导向晶态共轭有机材料设计合成及其可控制备的一种手段.     

Effect of surface area and heteroatom of porous carbon materials on electrochemical capacitance in aqueous and organic electrolytes

A series of porous carbon materials with wide range of specific surface areas and different heteroatom contents had been prepared using polyaniline as carbon precursor and KOH as an activating agent. Effect of surface area and heteroatom of porous carbon materials on specific capacitance was investigated thoroughly in two typical aqueous KOH and organic 1-butyl-3- methylimidazolium tetrafluoroborate/acetonitirle electrolytes. The different trends of capacitance performance were observed in these two electrolytes. Electrochemical analyses suggested that the presence of faradaic interactions on heteroatom-enriched carbon materials in organic environment is less significant than that observed in aqueous electrolytes. Thus, in aqueous electrolyte, a balance between surface area and heteroatom content of activated porous carbon would be found to develop a supercapacitor with high energy density. In organic electrolyte, the capacitance performance of porous carbon is strongly dependent on the surface area. The results may be useful for the design of porous carbon-based supercapacitor with the desired capacitive performance in aqueous and organic electrolytes.     

Effect of double-layer repulsion on foam film drainage

This paper presents an experimental validation of new theoretical development for foam film drainage, which focuses on the role of surface forces. The drainage of microscopic foam films (with radii smaller than 100 μm) from aqueous solutions of 10⁻⁶ to 10⁻⁴ mol/L sodium dodecyl sulphate (SDS) was studied by means of an improved Scheludko micro-interferometric technique which consisted of a conventional Scheludko cell, a high-speed camera system, and the software for digital analysis Optimas used for the digitisation of the interferometric images to obtain the monochromatic light intensity. The experimental technique allowed fast processing of the interferometric data for determining the transient film thickness with high accuracy. The zeta-potential of the air–water interface was determined from the electrophoretic mobility of micro-bubbles in SDS solutions of the same concentrations. Advanced predictions for the electrical double-layer repulsion at either constant surface potential or constant surface charge were employed. Significant discrepancy between the theoretical prediction and the experimental data was obtained. The analysis showed that the adsorption layer, which is located on the film surfaces, is far away from equilibrium, while the theory assumes condition close to equilibrium. In this term the interaction between the film surfaces is affected by the dynamics of the adsorption layers during the film drainage.     

Effect of chain length distribution on the phase behavior of polyglycerol fatty acid ester in water

The effect of the chain length distribution on the phase behavior, the structure of liquid crystals, and physicochemical properties was investigated in water/ polyglycerol fatty acid ester. Polyglycerol fatty acid esters with sharply distributed polyglycerol (10G*0.7L) and with broadly distributed polyglycerol (10G0.7L) were used. Unreacted polyglycerol in both surfactants was removed. 10G*0.7L forms hexagonal liquid crystals at a higher concentration than 10G0.7L. The effective cross-sectional area of the lipophilic parts in the hexagonal phase of 10G0.7L is smaller than that of 10G*0.7L owing to the difference in the chain length distribution. Evidently, 10G0.7L molecules are tightly packed in aggregates; therefore, 10G0.7L decreased the surface tension more strongly and promoted emulsification. Received: 11 January 2000 Accepted: 8 March 2000     

Effect of equilibrium and dynamic surface activity of surfactant on foam transport in porous medium

An apparatus containing a visual porous medium plate model and digital video recorder was employed to investigate the transportation of foam stabilized by sodium polyoxyethylene alkylether sulfate (AES), sodium dodecyl benzene sulfonate (SDBS) and TritonX-100 in porous medium. The results showed that transfiguration and fracture were the main transport manners for foam in the porous medium at high gas and liquid transfusion rate. The increase in probability of transfiguration in foam transport process corresponded to the higher flow impedance. A simple U-shape device was designed to investigate the rigidity of surfactant layer at the gas/liquid interface, and the equilibrium surface tension was assigned to be the key parameter which manifests the rigidity of surfactant interface layer. The dynamic surface tension of different surfactant system has also been measured, and the parameters gotten by Rosen model might be the measurement of dynamic elasticity of surfactant interface layer. There is consanguineous relation between the equilibrium surface activity or dynamic activity of the surfactants and the transport of the foam in the porous medium.     

Gas permeation of porous organic/inorganic hybrid membranes

Selective gas permeation of porous organic/inorganic hybrid membranes via sol-gel route and its thermal stability are described. Separation performance of the hybrid membrane was improved compared with porous membranes governed by the Knudsen flow, and gas permeability was still much higher than that through nonporous membranes. Additionally, it was shown that these membranes were applicable at higher temperatures than organic membranes.SEM observation demonstrated that the thin membrane was crack-free. Nitrogen physisorption isotherms showed the pore size was in the range of nanometers. Gas permeability through this membrane including phenyl group was in the range of 10^–8 [cc(STP) cm/(cm² s cmHg)] at 25°C. The ratios of O₂/N₂ and CO₂/N₂ were 1.5 and 6.0, respectively, showing the permeation was not governed by the Knudsen flow. The permeability decreased as the temperature increased. Furthermore, the specific affinity between gas molecules and surface was observed not only in the permeation data of the hybrid membranes but in the physisorption data. These results suggested that the gas permeation through the hybrid membrane was governed by the surface flow mechanism.Thermal analysis indicated that these functional groups were still stable at higher temperatures. The phenyl group especially remained undamaged even at 400°C.     

An assessment of analytical performance of dissolved organic nitrogen and dissolved organic phosphorus analyses in marine environments: a review

To better understand the cycling of marine dissolved organic matter, analytical methods are required allowing for data on dissolved organic nitrogen and phosphorus (DON and DOP) to be acquired with high analytical performance. The coverage of documented DON and DOP analytical performance is very limited; instead analytical data are mostly available for total dissolved N and P (TDN and TDP) analyses. This substitution overestimates analytical performance for DON and DOP measurements due to the cumulative effect of Standard Deviation applied for detection limit and precision evaluations. The little available data obtained by photolytic, chemical, a combination of both, and high temperature combustion methods indicate that current detection limit is 0.30 µM for DON and 0.010 µM for DOP. Precision for both analytes, in general, is ≤4.5%. The data on accuracy is scarce despite availability of Reference Materials for TDN and NO₃^? + NO₂^? analyses, and for the TDN measurement is <5%; even fewer data exist for TDP due to a lack of reference material for this analysis. The Beer–Lambert law is linear up to 200 µM for TDN and 5–6 µM for TDP. Current analytical abilities for DON/DOP measurements are not ready yet to set the level of dissolved organic carbon analysis. The advance in the analytical performance for DON and DOP measurements depends upon the possibility to improve the analytical performance for dissolved inorganic N and P measurements involved in DON and DOP estimations. For the DOP analysis, an international standard method becomes necessary to develop and evaluate collaboratively. The chemical oceanographers’ community should reconsider requirements needed for the coverage of analytical performance for DON and DOP measurements to make this data more shareable and transparent. The lack of these data protracts marine analysts from attaining further methods improvement and development.     

Copper supported on N-heterocyclic carbene-functionalized porous organic polymer for efficient oxidative carbonylation of methanol

A new heterogeneous catalyst for the oxidative carbonylation of methanol to dimethyl carbonate based on copper coordinated in N-heterocyclic carbene-functionalized porous organic polymer (Cu@PQP-NHC) was presented. The solid catalyst that featured relatively large surface area, hierarchical pore structure, and excellent swelling property, was prepared via a facile copolymerization reaction of tetra-vinylphosphonium salt and bis-vinylimidazolium salt, followed by successful immobilization of CuCl. Accordingly, the resulting Cu@PQP-NHC showed excellent catalytic performance for the oxidative carbonylation of methanol. A 10 mmol/l of Cu usage was sufficient for 9.3% conversion of methanol with a high TOF number of 57 h⁻¹. Importantly, the catalyst was easily recovered by simple centrifugation, and could be reused up to 10 consecutive recycles without obvious loss of its initial activity. Also, the solid catalyst showed negligible Cu leaching during the recycling, and 99% Cu species was still retained after reusing 10 times. The results in this study highlights the advantages of porous organic polymer supported NHC-Cu catalyst as a highly active and stable heterogeneous catalyst, providing a promising route for the synthesis of dimethyl carbonate.     

Effect of hydrophobically modified SiO2 nanoparticles on the stability of water-based SDS foam

In the present study, SiO₂ nanoparticles were first hydrophobically modified and then added into anionic surfactant sodium dodecyl sulfate (SDS) stabilized water-based foam to improve the foam stability. The foam stability was experimentally evaluated by measuring surface tension, Zeta potential and half-life of the foam. The foam stabilizing mechanism was also studied from a micro perspective by molecular dynamics simulation through analyzing the equilibration configuration and MSD curve of both SDS surfactant and water molecules. The results show that foam exhibits an optimal stability when SiO₂ concentration is 0.35 wt% under a specific surfactant concentration (0.5 wt%) in this work. The addition of SiO₂ nanoparticles with suitable concentration could improve the adsorption between SDS molecules and nanoparticles, thus limiting the movement of SDS and restricting the movement of surrounding water molecules, which is beneficial to enhance the foam stability.     

Postsynthetic amine modification of porous organic polymers for CO2 capture and separation

Porous organic polymers (POPs) constitute an important class of sorbents studied in various adsorption and separation processes. Their unique properties, including high surface areas, adjustable pore sizes, and surface chemistries make them ideal candidates for CO₂ capture. To achieve a high CO₂ adsorption capacity and selectivity, particularly at the low partition pressures required for post-combustion CO₂ capture or direct capture of CO₂ from the atmosphere, incorporating amines onto the polymer frameworks or within the pores has shown much promise. This review provides a comprehensive summary of recent studies on the synthesis and CO₂ capture performance of amine-functionalized POPs. The review also provides a detailed discussion of structure-performance relationships, focusing on how the loading amount and amine type influence CO₂ capture capacity, CO₂/N₂ selectivity, heat of adsorption, sorption kinetics, and recyclability of POPs. Additionally, the authors offer their perspective on the challenges associated with the practical implementation of amine-modified POPs for CO₂ capture.     

Effect of side‐chain length on the electrospinning of perfluorosulfonic acid ionomers

The effect of the side‐chain length (short side chain and long side chain, SSC and LSC, respectively) of perfluorosulfonic acid (PFSA) ionomers on the properties of nanofibers obtained by electrospinning ionomer dispersions in high dielectric constant liquids has been investigated with a view to obtaining electrospun webs as components of fuel cell membranes. Ranges of experimental conditions for electrospinning LSC and SSC PFSAs have been explored, with a scoping of solvents, carrier polymer and PFSA ionomer concentrations, and carrier polymer molecular weight. Under optimal conditions, the electrospun mats derived from SSC and from LSC PFSA show distinct fiber dimensions that arise from the different chain lengths of the respective ionomers. Enhanced interchain interactions in SSC PFSA with low equivalent weight compared to LSC PFSA result in a considerably lower average fiber diameter and a markedly narrower fiber size distribution. The proton conductivity of nanofiber mats of SSC and LSC PFSA with equivalent weights of 830 and 900 g mol^?1, respectively, are 102 and 58 mS cm^?1 at 80°C and 95% relative humidity. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

有机元素分析仪测定丙烯腈-衣康酸共聚物中衣康酸的含量

建立有机元素分析仪测定丙烯腈-衣康酸共聚物中衣康酸含量的方法。采用二甲基甲酰胺溶解、甲醇沉降纯化和灼烧的方法验证了样品纯度,用有机元素分析仪测定样品中氧的含量,通过计算氧含量得到了衣康酸的含量。采用苯甲酸建立标准工作曲线,氧的质量在30~1570μg范围内与响应信号成良好的线性关系,线性相关系数为0.999,测定结果的相对标准偏差为1.9%(n=6),加标回收率为99.1%~100.5%。该方法简单快速,准确度和精密度高,适合丙烯腈-衣康酸共聚物中衣康酸含量的快速测定。     

三嗪基多孔有机材料的合成及在固相微萃取应用中的研究进展

三嗪基多孔有机材料(TPOPs)具有较大的比表面积、可调的孔道结构、较高的热和化学稳定性、丰富的π键体系等诸多优点,目前被广泛应用于气体储存、催化、能源转化和吸附等诸多领域。基于TPOPs的固相微萃取(SPME)技术近年来引起了人们的极大兴趣,成为样品前处理技术领域的研究热点之一。该文简要地综述了近年来TPOPs的合成方法及其在固相微萃取领域的应用与发展,并对该领域研究进行了展望。     

预混天然气在多孔介质燃烧器中的燃烧与传热

在一台小型渐变型多孔介质燃烧器上进行了预混天然气燃烧与传热试验研究,探讨了天然气速度和多孔介质厚度对多孔介质燃烧室的温度分布、排烟温度和流动阻力的影响。结果表明,天然气在渐变型多孔介质燃烧器中燃烧稳定,燃烧室与水冷夹套间的换热受天然气速度和多孔介质厚度影响,换热效果比空管中燃烧明显增强,同时预混天然气通过多孔介质的进出口压差随着天然气速度和多孔介质厚度的增加而增加。     

多孔雪花状氧化锌分级纳米结构的制备、表征及其光催化性能研究

在H2O和乙二醇(EG)构成的二元体系中,通过Zn AC2与NH4F和H2O的水热反应制备了六角雪花状Zn OHF。Zn OHF在空气中退火,制备出了由单晶Zn O纳米片构建的多孔六角雪花状Zn O。用X射线衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM)及其热重等多种手段对产物进行结构表征,并提出了可能的化学反应。以甲基橙和酸性大红为例,研究了其光催化性能,结果表明,多孔雪花状Zn O是一种有效的光催化剂。     

多孔有机笼毛细管电色谱手性柱的制备及应用

多孔有机笼(POCs)是一种新型的具有稳定有序三维空腔结构的多孔材料。通过2-羟基-1,3,5-均苯三甲醛与1R,2R-1,2-二苯基乙二胺发生席夫碱的缩合反应,合成了一种具有羟基功能基团的单一手性POCs材料;将其均匀涂敷在毛细管壁上制成色谱柱,利用电色谱柱成功拆分了二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺4种手性化合物。探究了分离电压、缓冲溶液浓度及其pH值等因素对手性拆分的影响,获得了4种手性物质在POCs色谱柱上的最佳拆分条件。实验研究表明,二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺获得优化分离效果所需的工作电压分别为13、14、14和12 kV;二氢黄酮适宜Tris-H₃PO₄缓冲溶液浓度为0.075 mol/L,吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺适宜Tris-H₃PO₄缓冲溶液浓度为0.100 mol/L; 4种手性物质得到最佳分离效果时的pH值均为3.51。二氢黄酮、吡喹酮、萘普生和3,5-二硝基-N-(1-苯乙基)苯甲酰胺均达到基线分离,分离度分别为2.99、2.10、2.58和3.59。该POCs色谱柱还成功拆分了o,m,p-碘苯胺、o,m,p-硝基苯胺两种位置异构体。该研究表明POCs手性电色谱柱具有良好的手性识别能力,是一种优秀的手性分离材料,具有很大的电色谱手性分离应用前景。     

Pd/Cu-free Heck and Sonogashira coupling reactions applying cobalt nanoparticles supported on multifunctional porous organic hybrid

A new heterogeneous cobalt catalyst has been synthesized by immobilizing Co species onto a nitrogen-rich porous organic polymer (Co@imine-POP). The heterogeneous catalyst synthesized was efficient in Heck and Sonogashira cross-coupling reactions in green media under mild reaction conditions without inert air and phase transfer agents. This phosphine-, copper-, and palladium-free catalyst was stable under the reaction conditions and could be reused for at least eight successive runs without a discernible decrease in its catalytic activity.