Exfoliation of poly(ethylene glycol)-intercalated graphite oxide composite in water without sonication

A novel method for exfoliating graphite oxide(GrO)was implemented through the mass water absorption of a GrO–poly(ethylene glycol)(GrO–PEG)composite.The GrO–PEG composite was prepared by intercalating PEG into the lamellae of GrO,and the variation of the basal spacing was measured by X-ray diffraction analysis.The yield of graphene was measured with an ultraviolet–visible spectrophotometer,and the properties of graphene oxide(GO)were characterized by atomic force microscopy,transmission electron microscopy(TEM),Raman spectrometry,and Fourier transform infrared spectroscopy.Increasing intercalation time was found to improve the yield of GO,whereas increasing the PEG molecular weight had the opposite effect.The GO sheets produced from the intercalation–absorption–exfoliation process were found to be a four-layer structure.TEM and Raman analyses indicate that the graphitized structure and oxygen groups of GO were preserved during the exfoliation process.Most importantly,the results show that good-quality GO could be prepared via a mild method involving water absorption of a GrO–PEG composite.

Effect of poly(ethylene glycol) molecular weight on CO_2/N_2 separation performance of poly(amide-12-b-ethylene oxide)/poly(ethylene glycol) blend membranes

Membranes from block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074) and its blends with different molecular weight poly(ethylene glycol)(PEG)(200, 400, 600, 1500, 4600 and 8000) were prepared. The thermal properties and structures of Pebax1074/PEG blend membranes were characterized by DSC and SEM, and the gas permeation properties of CO_2 and N_2 were also investigated at different temperatures. For Pebax1074/PEG blend membranes with low molecular weight PEG(MW≤ 600), higher gas permeabilities than Pebax1074 were achieved. The permeability increased with the increase of PEG molecular weight. The addition of low molecular weight PEG resulted in decrease in activation energy of permeation. For Pebax1074/PEG blend membranes with high molecular weight PEG(MW≥ 1500), due to the melt of PEO phase crystals, the gas permeation properties of blend membranes were temperaturedependent, which could be divided into crystalline region, transition region and amorphous region according to two different transition temperatures. PEG molecular weight and operation temperature determined different gas permeation properties of Pebax1074/PEG blend membranes in three regions. The activation energies of permeation in crystalline region were larger than those in amorphous region.

The Synthesis of Poly(ethylene oxide)-Block-Polybutylacrylate

Poly(ethylene oxide) containing azogroups(pre PEO) was prepared by reacting azoisobutyronitrile (AIBN) with poly( ethylene glycol ) (PEG). The molecular weight of pre PEO was depended on the reaction time, the ratio of PEG to AIBN and the molecular weight of PEG. Pre PEO decomposed in the presence of butylacrylate (BA) monomer to form poly ethylene oxide block butylacrylate copolymers(PEO b PBA). The molecular weights of PEO b PBA and the homopolymer of PBA were proportional to the ratio of BA to pre PEO. The purified block copolymers were charactherized using IR, 1H NMR and GPC.

Poly Ethylene Glycols (PEG) and Micelles as Efficient Catalysts for the Oxidation of Xanthine Derivatives under Conventional and Non-Conventional Conditions

Oxidation of Xanthine alkaloid have been studied with various one and two electron oxidizing agents using PEGs and micelle forming surfactants. The reaction is too sluggish in solution phase, but moderately fast in presence of PEGs and micelles. However, the reactions are dramatically enhanced under microwave irradiations. Present protocol has several advantages, such as solvent-free conditions, during work-up, fast reaction times, high yields, eco-friendly operational and experimental simplicity, readily available additives as catalysts.

Co-electrolysis of ethylene glycol and carbon dioxide for formate synthesis

Co-electrolysis of waste plastics and carbon dioxide(CO_(2)) into value-added chemicals or fuels is a promising pathway for a sustainable society, but efficient and selective conversion remains a challenge. Herein, a gold-mediated nickel hydroxide(Au/Ni(OH)_(2)) is developed to oxidize waste plastic-derived ethylene glycol(EG) into formate. In-situ electrochemical experiments and theoretical results reveal that the introduction of Au favors the redox properties and EG adsorption behavior of Ni(OH)_(2). The Au/Ni(OH)_(2) catalyst shows an excellent formate selectivity of >90% at high current densities of above 100 m A cm^(-2). When coupled with sputtered bismuth(Bi) cathode for CO_(2) reduction, a high formate Faradic efficiency(FE) of 188.2% at 200 m A cm^(-2)and a good formate productivity of 7.33 mmol m^(-2)s^(-1)at 10 A are obtained in a flow cell and a zero-gap membrane electrode assembly(MEA) cell, respectively. This work demonstrates a promising strategy to convert waste plastics and CO_(2) into valuable products.

Nanostructure and Formation Mechanism of Pt-WO_3/C Nanocatalyst by Ethylene Glycol Method

Pt-WO3 nanoparticles uniformly dispersed on Vulcan XC-72R carbon black were prepared by an ethylene glycol method.The morphology,composition,nanostructure,electrochemical characteristics and electrocatalytic activity were characterized,and the formation mechanism was investigated.The average particle size was 2.3 nm,the same as that of Pt/C catalyst.The W/Pt atomic ratio was 1/20,much lower than the design of 1/3.The deposition of WO3·xH2O nanoparticles on Vulcan XC-72R carbon black was found to be very difficult by TEM.From XPS and XRD,the Pt nanoparticles were formed in the colloidal solution of Na2WO4,the EG insoluble Na2WO4 resulted in the decreased relative crystallinity and increased crystalline lattice constant compared with those of Pt/C catalyst and,subsequently,the higher specific electrocatalytic activity as determined by CV.The Pt-mass and Pt-electrochemically-active-specific-surface-area based anodic peak current densities for ethanol oxidation were 422.2 mA·mg-1Pt and 0.43 mA·cm-2Pt,1.2 and 1.1 times higher than those of Pt/C catalyst,respectively.

Novel P-doping-tuned Pd nanoflowers/S,N-GQDs photo-electrocatalyst for high-efficient ethylene glycol oxidation

Traditional photo-electcatalyst structures of small noble metal nanoparticles assembling into large-scale photoactive semiconductors still suffer from agglomeration of noble metal nanoparticles,insufficient charge transfer,undesirable photoresponse ability that restricted the photo-electrocatalytic performance.To this end,a novel design strategy is proposed in this work,namely integrating small-scale photoactive materials(doped graphene quantum dots,S,N-GQDs)with large-sized noble metal(Pd P)nanoflowers to form novel photo-electrocatalysts for high-efficient alcohol oxidation reaction.As expected,superior electrocatalytic performance of Pd P/S,N-GQDs for ethylene glycol oxidation is acquired,thanks to the nanoflower structure with larger specific surface area and abundant active sites.Furthermore,nonmetal P are demonstrated,especially optimizing the adsorption strength,enhancing the interfacial contact,reducing metal agglomeration,ensuring uniform and efficient doping of S,N-GQDs,and ultimately significantly boost the catalytic activity of photo-electrocatalysts.

Fabrication of 3D hollow acorn-shell-like PtBi intermetallics via a surfactant-free pathway for efficient ethylene glycol electrooxidation

The synthesis of atomically ordered Pt-based intermetallic electrocatalysts for the direct alcohol fuel cells generally requires the addition of surfactants or the high-temperature annealing.However,some residual surfactants on the surface of the assynthesized catalysts would prevent the exposure of catalytic active sites,the high-temperature annealing process is easy to accelerate the sintering of the metal,which both lead to the decline of electrocatalytic performance.Herein,we construct the atomically ordered bimetallic PtBi intermetallics with clean surfaces and unique three-dimensional hollow acorn-shell-like structure(3D PtBi HASL)by a simple,low-temperature,surfactant-free one-pot synthetic approach.Benefiting from the special hollow structures,the obtained 3D PtBi HASL intermetallics expose abundant accessible active sites.Moreover,the introduction of oxophilic metal Bi can enhance adsorption of OHads,thereby significantly facilitating removal of poisoned intermediates.Density functional theory(DFT)simulations further indicate that formation of the PtBi intermetallic phase with the downshift of the Pt d-band center endows 3D Pt49.4Bi50.6 HASL intermetallics with significantly attenuated COads and enhanced OHads adsorption,bringing about the boosting electrocatalytic property.The mass activity of the 3D Pt49.4Bi50.6 HASL intermetallics for ethylene glycol oxidation reaction is as high as 24.67 A·mgPt^(−1),which is 12.98 times higher than that of commercial Pt/C(1.90 A·mgPt^(−1)).This work may inspire the design of Pt-based intermetallics as high-efficiency anode electrocatalysts for fuel cell applications.

PdPbBi nanoalloys anchored reduced graphene-wrapped metal-organic framework-derived catalyst for enhancing ethylene glycol electrooxidation

For future clean energy demand,it is essential to develop highly efficient and durable materials for use in renewable energy conversion devices.Herein,we report an electrocatalyst loaded with Pd-Pb-Bi nanoalloys on reduced graphene(rGO)-wrapped In_(2)O_(3)(PdPbBi@rGO/In_(2)O_(3))prepared by a hydrothermal method.PdPbBi@rGO/In_(2)O_(3)exhibits higher forward current density(229.12 mA·cm^(-2)),larger electrochemical active surface area(ECSA)(85.87 m^(2)·g^(-1)Pd),smaller impedance(12.68Ω)and lower E_(onset)(-0.56 V)than commercial Pd/C.Specifically,the current density and ECS A are 8.46 and3.38 times higher than those of commercial Pd/C(27.07 mA·cm^(-2),25.41 m^(2)·g^(-1)Pd),respectively.Furthermore,the oxidation mechanism of ethylene glycol and the removal of carbon monoxide[CO]_(ads)from the surface of Pd are also discussed in detail.The columnar support structure wrapped by rGO provides a huge active surface area for catalysis.Moreover,the electronic effect of Pd-PbBi nanoalloys can accelerate the removal of CO intermediate species,obtain more Pd active sites and improve the electrocatalytic performance.Our first synthesis of this highly electrocatalyst offers promising value for commercial application in direct fuel cells.

Controlled synthesis of MOF-derived hollow and yolk–shell nanocages for improved water oxidation and selective ethylene glycol reformation

Delicately designed metal–organic framework(MOF)-derived nanostructured electrocatalysts are essential for improving the reaction kinetics of the oxygen evolution reaction and tuning the selectivity of small organic molecule oxidation reactions.Herein,novel oxalate-modified hollow CoFe-based layered double hydroxide nanocages(h-CoFe-LDH NCs)and yolk–shell ZIF@CoFe-LDH nanocages(ys-ZIF@CoFe-LDH NCs)are developed through an etching–doping reconstruction strategy from a Co-based MOF precursor(ZIF-67).The distinctive nanostructures,along with the incorporation of the secondary metal element and intercalated oxalate groups,enable h-CoFe-LDH NCs and ys-ZIF@CoFe-LDH NCs to expose more active sites with high intrinsic activity.The resultant h-CoFe-LDH NCs exhibit outstanding OER activity with an overpotential of only 278 mV to deliver a current density of 50 mA cm^(-2).Additionally,controlling the reconstruction degree enables the formation of ys-ZIF@CoFe-LDH NCs with a yolk–shell nanocage nanostructure,which show outstanding electrocatalytic performance for the selective ethylene glycol oxidation reaction(EGOR)toward formate,with a Faradaic efficiency of up to 91%.Consequently,a hybrid water electrolysis system integrating the EGOR and the hydrogen evolution reaction using Pt/C||ys-ZIF@CoFe-LDH NCs is explored for energy-saving hydrogen production,requiring a cell voltage 127 mV lower than water electrolysis to achieve a current density of 50 mA cm^(-2).This work demonstrates a feasible way to design advanced MOF-derived electrocatalysts toward enhanced electrocatalytic reactions.

In situ time-resolved FTIRS study of adsorption and oxidation of ethylene glycol on Pt(100) electrode

Adsorption and oxidation of ethylene glyco(EG) on Pt(100) electrode were studied by in situ timeresolved FTIRS (TRFTIRS). The TRFTIR spectra recordedat 0.10 V illustrate that an IR band appears near 2050 cm?at t > 5 s, corresponding to linearly bonded CO formed indissociative adsorption of EG. The TRFTIR results haveconfirmed also that CO species are distributed uniformly onPt(100) surface. Another band appears near 2342 cm?1 at > 70 s, associating with IR absorption of CO2 produced inthe direct oxidation of EG. With the increase of electrodepotential, the direct oxidation of EG becomes gradually themain reaction. When the potential is above 0.40 V, the oxidation of EG occurs mainly via the reactive intermediates, i.especies containing –COOH determined by in situ TRFTIRS.

Bimetallic Au/Pd catalyzed aerobic oxidation of alcohols in the poly(ethylene glycol)/CO_(2) system

Bimetallic Au/Pd nanoparticles were prepared and used to catalyze oxidation of alcohols in the poly(ethylene glycol) (PEG)/CO_(2) biphasic system using O2 as the oxidant without adding any base.The catalytic activity of Au/Pd bimetal with different mole ratios was studied using benzyl alcohol as the substrate.It was found that bimetallic Au/Pd nanoparticles with Au:Pd=1:3.5 had higher catalytic activity than monometallic Au,Pd and the bimetallic Au/Pd nanoparticles with other molar ratios.The effect of CO_(2) pressure on the oxidation of benzyl alcohol and 1-phenylethanol in PEG/CO_(2) was investigated.It was demonstrated that CO_(2) pressure could be used to tune the conversion and selectivity of the reactions effectively.α,β-Unsaturated alcohols were also studied and found to be more reactive than benzyl alcohol and 1-phenylethanol.Recycling experiments showed that the Au/Pd/PEG/CO_(2) catalytic system could be recycled at least four times without reducing the activity.In addition,the catalytic system is clean and the products can be separated easily.

乙二醇装置奥氏体不锈钢封头的开裂原因及预防对策

采用无损检测和金相、硬度、铁素体含量等理化检验,对某企业乙二醇装置奥氏体不锈钢封头的开裂原因进行了分析,并提出了预防措施。结果表明:不锈钢封头的开裂形式为穿晶型应力腐蚀开裂;冷成形后的封头组织中含有大量形变诱发马氏体,且硬度大幅升高,在焊接残余应力和冷成形加工残余应力的共同作用下,封头发生氯化物应力腐蚀开裂,且含乙酸和甲酸的弱酸性环境对开裂起到显著的促进作用。建议对冷成形后的封头进行固溶处理,以消除加工硬化的影响。

纳米级钛硅分子筛合成及其催化乙烯制乙二醇性能

以四丙基氢氧化铵为模板剂,钛酸四丁酯为Ti源,硅酸四乙酯(TEOS)、钠型硅溶胶或铵型硅溶胶分别为Si源,通过水热晶化法制备出一系列钛硅分子筛(TS-1),利用X射线衍射仪、自动物理吸附仪、荧光光谱仪、傅里叶红外光谱仪、扫描电子显微镜、紫外可见分光光度计等仪器对合成的样品进行了表征,考察了Ti源引入温度、Si源种类、晶化时间以及硅钛比[n(Si)/n(Ti),下同]对合成TS-1的影响,并对比评价了系列TS-1催化乙烯制乙二醇(EG)的性能。结果表明:在常温下引入Ti源,选择TEOS作Si源,晶化时间为1 d,硅钛比为50的条件下所合成TE-50 N-1样品的催化性能最优,H_(2)O_(2)转化率为80.04%,EG选择性为97.19%。

我国环氧乙烷与乙二醇的市场分析

环氧乙烷与乙二醇是乙烯下游两大重要的化工品。近几年来,环氧乙烷行业产能面临扩张局面,但产能增速高于需求增速,供需矛盾加剧,盈利能力减弱,市场价格以持续低位震荡为主;乙二醇行业在炼化一体化以及煤化工的推动下也出现了产能快速增长的局面,市场竞争压力扩大,进口量持续缩减,部分老装置出现长停状态,市场价格维持宽幅震荡运行。文章就环氧乙烷与乙二醇供需情况、市场价格以及未来发展前景进行了分析。

冷凝+催化氧化处理技术在罐区及装车栈台油气处理系统中的应用

兰州石化公司采用乙烯运行一部储运区域罐区及装车栈台,在实际运行过程中,会排放出苯、甲苯、二甲苯等对环境有害的有机物,排放的尾气具有浓度高、波动大的特点,目前采用上海东化环境工程有限公司的“冷凝+催化氧化”工艺技术,对三苯罐区和装车栈台的油气进行综合治理。根据现场运行情况,不断优化尾气处理设施的运行参数,对装置进行技术改造,使罐区及装车站台的尾气达标排放,排放指标满足国标GB 31571—2015《石油化学工业污染物排放标准》中表6规定的特别污染物排放的要求,苯≤4 mg/Nm^(3),甲苯≤15 mg/Nm^(3),异丙苯≤50 mg/Nm^(3),非甲烷总烃转化率最高能达到99%以上,在系统保证安全的前提下,环保达标排放。

煤制乙二醇主要工艺单元技术新进展

在碳达峰、碳中和目标下,实现煤化工行业高质量发展是当务之急。从我国建成世界上第一套煤制乙二醇工业化示范装置开始,煤制乙二醇迎来了井喷式的大发展。本文对草酸酯催化加氢制乙二醇技术主要单元的技术和工艺进行了总结和梳理,着重分析了催化剂和工艺操作注意事项,以期为业内提供一些参考,共同促进煤制乙二醇行业的技术进步和发展。

琥珀酸美托洛尔中潜在的环氧乙烷类基因毒性杂质含量测定研究

目的对琥珀酸美托洛尔中潜在的环氧乙烷类基因毒性杂质含量进行测定。方法采用高效液相色谱法测定琥珀酸美托洛尔中含有环氧乙烷结构的杂质XI含量。色谱柱采用Wondasil C_(18)-WR柱(250 mm×4.6 mm,5.0μm),以流动相A为缓冲液(取磷酸二氢钾2.72 g,高氯酸钠一水合物6.13 g,加水1000 mL溶解后,用1.0 mol·L^(-1)氢氧化钠溶液调pH值至6.0),流动相B为甲醇的梯度洗脱,流速1.0 mL·min^(-1),进样量40μL,柱温30℃,检测波长280 nm。结果杂质XI在线性范围为0.8523~6.8183μg·mL^(-1)内,r=0.9999,检测限浓度为0.4261μg·mL^(-1),定量限浓度为0.8523μg·mL^(-1),平均回收率为94.21%。结论本研究准确可靠、专属性强且重现性好,可为琥珀酸美托洛尔中潜在的环氧乙烷类基因毒性杂质的质量控制和安全性评价提供科学依据。

Zn-Al混合氧化物催化尿素醇解合成碳酸乙烯酯的研究

采用共沉淀法制备了Zn-Al类水滑石前体,考察了不同煅烧温度下制备的Zn/Al复合氧化物催化剂对尿素和乙二醇合成碳酸乙烯酯(EC)收率的影响。结果表明,873 K温度下煅烧的催化剂在反应中表现出最高的催化活性,EC收率为91.1%,催化剂重复使用4次活性没有降低。通过TG、XRD对催化剂进行了表征,并采用ICP测定了该复合氧化物中Zn、Al在反应体系中的化学溶解量,考察了溶解情况和收率之间的关系,结果发现适当Al的溶解能够与Zn起到很好的协同作用,从而促进EC的合成。