Critical temperatures and pressures of reacting mixture in synthesis of dimethyl carbonate with methanol and carbon dioxide

Critical temperatures and pressures of nominal reacting mixture in synthesis of dimethyl carbonate （DMC） from methanol and carbon dioxide （quaternary mixture of carbon dioxide ＋ methanol ＋ water ＋ DMC） were measured using a high-pressure view cell. The results suggested that the critical properties of the reacting mixture depended on the reaction extent as well as its initial composition （initial ratio of carbon dioxide to methanol）. Such information is essential for determining the reaction conditions when one intends to carry out the synthesis of DMC with CO2 and methanol under supercritical conditions.

One-Pot Synthesis of Dimethyl Carbonate over Basic Zeolite Catalysts

One-pot synthesis of dimethyl carbonate (DMC) from methanol, propylene oxide (PO) and carbon dioxide has been investigated using the basic zeolites as catalysts. Among the zeolites studied, Beta showed the best catalytic performance for DMC production. That the desilication of zeolite structure resulted in a hierarchical porosity of Beta, leading to more amount of KOH can be loaded on the surface of zeolite and therefore enhancing the base strength of the catalyst was proposed to be the reason for improved catalytic performance.

Synthesis of dimethyl carbonate by gas-phase oxidative carbonylation of methanol in the presence of solid catalyst I. Catalyst preparation and catalytic Properties

The gas-phase synthesis of dimethyl carbonate (DMC) from methanol, carbon monoxide and oXygen has here Studied in a flow system at atomspheric Pressure. A series of Catalyst used in this reaCtion have been prepared and evaluated. The influence of trivared carbon supporters, alkaline metal Promoters and operation conditions on DMC opthesis reaction has been discussed. Under the conditions of 130℃, CO/O2=1 .96, SV=3340h-1, the space-time yield (STY) of DMC over PdCl2-CuCl2-CH3COOK/ac. catalyst is 217g/l-cat h,which is higher than what is published in the literatUre so far.

Continuous dimethyl carbonate synthesis from CO_(2) and methanol over Bi_(x)Ce_(1-x)O_(δ) monoliths:Effect of bismuth doping on population of oxygen vacancies,activity,and reaction pathway

We evaluated bismuth doped cerium oxide catalysts for the continuous synthesis of dimethyl carbonate(DMC)from methanol and carbon dioxide in the absence of a dehydrating agent.Bi_(x)Ce_(1-x)O_(δ)nanocomposites of various compositions(x=0.06-0.24)were coated on a ceramic honeycomb and their structural and catalytic properties were examined.The incorporation of Bi species into the CeO_(2) lattice facilitated controlling of the surface population of oxygen vacancies,which is shown to play a crucial role in the mechanism of this reaction and is an important parameter for the design of ceria-based catalysts.The DMC production rate of the Bi_(x)Ce_(1-x)O_(δ) catalysts was found to be strongly enhanced with increasing Ov concentration.The concentration of oxygen vacancies exhibited a maximum for Bi_(0.12)Ce_(0.88)O_(δ),which afforded the highest DMC production rate.Long-term tests showed stable activity and selectivity of this catalyst over 45 h on-stream at 140°C and a gas-hourly space velocity of 2,880 mL·g_(cat)^(-1)·h^(-1).In-situ modulation excitation diffuse reflection Fourier transform infrared spectroscopy and first-principle calculations indicate that the DMC synthesis occurs through reaction of a bidentate carbonate intermediate with the activated methoxy(-OCH_(3))species.The activation of C0_(2) to form the bidentate carbonate intermediate on the oxygen vacancy sites is identified as highest energy barrier in the reaction pathway and thus is likely the rate-determining step.

Direct synthesis of dimethyl carbonate over rare earth oxide supported catalyst

Solid base catalysts for the direct synthesis of dimethyl carbonate(DMC)from carbon dioxide,methanol,and propylene oxide were prepared by loading KCl and K_(2)CO_(3) on the surface of La_(2)O_(3),Y_(2)O_(3),CeO2 and Nd_(2)O_(3).The catalysts were characterized by thermogravimetric analysis(TGA)and X-ray diffraction(XRD)techniques.The catalytic activities were efficiently influenced by the preparation conditions.The optimal loading amount of K_(2)CO_(3) is 17.6%(mass)for KCl-K_(2)CO_(3)/Y_(2)O_(3) and 22.2%for other catalysts.Supports affected the activity of catalyst.KCl-K_(2)CO_(3)/Nd_(2)O_(3) exhibited the highest activity.The activity of KCl-K_(2)CO_(3)/Y_(2)O_(3) increased with the increase of calcination temperature in the range of 800℃–900℃.The formation of KYO2,Y_(3)O_(4)Cl or YOX species probably promoted the catalysts.

A1_2O_3 Effect on the Catalytic Activity of Cu-ZnO-Al_2O_3-SiO_2 Catalysts for Dimethyl Ether Synthesis from CO_2 Hydrogenation

The effect of Al2O3 on the Cu-ZnO-Al2O3-SiO2 catalysts prepared by a pseudo sol-gel method has been investigated and these catalysts were characterized by XRD, H2-TPR, XPS, NH3-TPD and CO2- TPD techniques. As revealed by XRD and H2-TPR, the added alumina produces high dispersion of CuO and makes the reduction of CuO difficult. XPS analysis detects a remarkably high Al^3＋ enrichment at the surface of calcined samples, along with a decrease of Eb of Cu 2p3/2, which confirms the Cu-Al interaction. Another important role of Al203 would be to incorporate into the SiO2 structure to form the acid-base sites for ether formation. The reaction results shows that the addition of Al2O3 exhibits a promoting effect on the CO2 conversion only when its content is below 1.4%, and an optimal DME selectivity is obtained when 4.0%Al2O3 is added, indicating a better ＇synergistic effect＇ is present between the methanol forming component and the acidic component in bifunctional catalysts. Possible relationship between the catalytic activity and the Cu-Al interaction as well as the surface acidity is discussed.

Ionic liquid mediated CO_2 activation for DMC synthesis

Promoted catalytic reaction between methanol and CO2 for dimethyl carbonate （DMC） synthesis is conducted over K2CO3/CH3I catalyst in the presence of ionic liquid under microwave irradiation. The effect of ionic liquids incorporated with microwave irradiation on the yield of DMC is investigated. DMC was found to form at lower temperature in a relative short time, which indicated an enhanced catalytic process by ionic liquid. Among the ionic liquids used, 1-butyl-3-methylimidazolium chloride is the most effective promoter. Density functional theory calculations indicate that CO2 bond lengths and angles changed due to the molecular interaction of ionic liquid and CO2, resulting in the activation of CO2 molecules and consequently the acceleration of reaction rate.

Recent progress in the synthesis of graphene/CNT composites and the energy-related applications

Graphene and carbon nanotube(CNT) are representative carbon nanomaterials which have aroused numerous research interest due to their extraordinary material properties and promising application potentials,especially in the energy storage and conversion areas.However,the agglomeration happening in these materials has largely blocked their applications.Hybridization of CNT with graphene can,on one hand,prevent the agglomeration behavior,on the other hand,generate a synergistic effect between them with enhanced physical and chemical properties.There have been many studies conducted to find out the suitable approaches to synthesize graphene/CNT composites,and realize the application potentials of these structures.Based on the recent advances,this paper reviews the current research progress that has been achieved in synthesizing graphene/CNT composites,and the energy-related applications.Through this review,we aim at stimulating more significant research on this subject.

Conductive hydrogels incorporating carbon nanoparticles:A review of synthesis,performance and applications

As one of the most rapidly expanding materials,hydrogels have gained increasing attention in a variety of fields due to their biocompatibility,degradability and hydrophilic properties,as well as their remarkable adhesion and stretchability to adapt to different surfaces.Hydrogels combined with carbon-based materials possess enhanced properties and new functionalities,in particular,conductive hydrogels have become a new area of research in the field of materials science.This review aims to provide a comprehensive overview and up-to-date examination of recent developments in the synthesis,properties and applications of conductive hydrogels incorporating several typical carbon nanoparticles such as carbon nanotubes,graphene,carbon dots and carbon nanofibers.We summarize key techniques and mechanisms for synthesizing various composite hydrogels with exceptional properties,and represented applications such as wearable sensors,temperature sensors,supercapacitors and human-computer interaction reported recently.The mechanical,electrical and sensing properties of carbon nanoparticles conductive hydrogels are thoroughly analyzed to disclose the role of carbon nanoparticles in these hydrogels and key factors in the microstructure.Finally,future development of conductive hydrogels based on carbon nanoparticles is discussed including the challenges and possible solutions in terms of microstructure optimization,mechanical and other properties,and promising applications in wearable electronics and multifunctional materials.

Synthesis and applications of carbon nanospheres:A review

The synthesis of carbon nanospheres(CNS)has developed rapidly in recent years,and they are widely used owing to the tunability of their porous structures and surface properties and the unique hydrodynamic advantages conferred by their spherical structures.This review summarizes the methods used to synthesize CNS and their applications in various fields.The review first describes the four main methods of CNS synthesis,i.e.the template,spray-drying,hydrothermal carbonization,Stöber and chemical vapor depo-sition method.Next,applications in the fields of energy storage,adsorption,biological medicine,and catalysis are expounded.Finally,some insights on the development and design of CNS are presented.

Challenging the limitation:Synthesis and application of complexes with the highest carbon coordination number in plane

Subject Code:B02With the support by the National Natural Science Foundation of China and the National Basic Research Program of China,the research team led by Prof.Xia Haiping(夏海平)of Xiamen University described the first example of CCCCC pentadentate chelate with all binding atoms being carbon atoms.This result represents a new record of planar carbon coordination number for a transition metal,which was

A review of helical carbon materials structure,synthesis and applications

The helical structures possess unique physical and chemical properties,such as superelasticity,high specific strength,chirality,and electromagnetic cross-polarization characteristics.With the development of nanoscience and nanotechnology,helical structures with various scales have been discovered or synthesized artificially.Among them,the helical carbon materials receive much attention around the world.Herein,we present a brief review of the development of helical carbon materials in terms of structures,synthesis techniques and mechanisms,and applications.The controllable designing of catalysts,carbon sources and reaction parameters plays a key role to optimize the properties of the helical carbon materials.At the same time,the applications in microwave absorption devices,sensors,catalysts,energy conversions and storage devices,and solar cell are also presented.For the good chemical and physical properties,helical carbon materials have a good application prospect in many fields.The potential issues and future opportunities of the helical carbon materials are also proposed.

Carbon nanotube: Controlled synthesis determines its future

Carbon nanotubes(CNTs) have received broad attention in the past decades due to their excellent physical and chemical properties and thus been regarded as a powerful candidate for future star-materials. Although various CNT products and their related applications have been demonstrated recently, their performance can hardly meet the researchers’ expectations compared with their theoretical properties. The current predicament is caused by the immature synthesis method, including the basic science and the producing technology. As the synthesis with controlled structures determines its future, this review summarizes the progress on the basic research and industrialization of CNTs in the past decades, including the fine structure control, aggregation status design and scale-up production, and further points out the way for the future development of CNTs combining with specific applications.

焙烧气氛对棒状CeO_(2)催化CO_(2)和甲醇直接合成DMC的影响

二氧化碳(CO_(2))和甲醇(MeOH)直接合成碳酸二甲酯(DMC)是一条符合绿色化学要求的DMC制备路线,并可实现CO_(2)资源化利用。氧化铈(CeO_(2))基催化剂被广泛应用于该反应,目前研究主要集中在形貌调控与杂原子掺杂对催化剂催化性能的影响。采用水热合成法制备了棒状CeO_(2)前驱体,然后在不同的焙烧气氛(分别为H_(2)、N_(2)、air和O_(2))中处理前驱体得到相应催化剂,然后将催化剂应用于2-氰基吡啶(2-cp)作脱水剂的CO_(2)和MeOH直接合成DMC(加入0.10 mol MeOH、0.05 mol 2-cp和0.32 g催化剂,在120℃、5 MPa的条件下反应2 h)中,研究了焙烧气氛对催化剂催化性能的影响。采用XRD、N2吸/脱附和SEM等对催化剂的晶相结构、织构性质和形貌等进行了表征。结果表明,4种催化剂在结构性质和形貌方面没有表现出明显差异,而催化剂表面的Ce价态与酸碱位点密切相关。催化剂表面存在的丰富缺陷位点使其具有较大的比表面积和平均孔径(CeO_(2)-air的比表面积和平均孔径分别为65.44m^(2)/g和30.06nm),催化剂主要暴露的CeO_(2)(111)晶面能促进DMC的生成。与其他3种催化剂相比,CeO_(2)-air因表面含有最丰富的中强酸碱位点和总的酸碱位点,以及较强的弱酸酸性而表现出最好的催化性能,该催化剂作用下的DMC产率和DMC选择性分别为83.2%和99.3%。

甲基丙烯酸长碳链酯的合成及应用研究进展

概述了甲基丙烯酸长碳链酯的合成方法及反应机理,重点介绍了传统磺酸类、离子交换型树脂、固体酸、碱金属类、金属负载型、离子液体等催化剂合成甲基丙烯酸长碳链酯的研究进展,并梳理了每种催化剂在应用过程中的特点,综述了国内外关于甲基丙烯酸长碳链酯在材料、纺织、涂料等应用领域的研究进展。由于甲基丙烯酸长碳链酯的酯化产量不高,应用领域也比较有限,未来应继续开发合成甲基丙烯酸长碳链酯的绿色、环保催化剂体系,扩大其在不同应用领域的研究。

MOF基材料在催化合成碳酸二甲酯中的应用

碳酸二甲酯(DMC)被誉为有机合成的新基石,制备新型高效的合成DMC催化剂对推进DMC工业化发展具有重要意义。金属-有机框架(MOF)由于具有比表面积大、结构多样和多孔性等特点,能够针对性地设计其组分与结构,在催化领域得到了广泛地研究与应用。本综述总结了MOF基材料的结构调控策略及其在催化合成DMC中的应用,包括缺陷态调控、有机官能团功能化、混合金属功能化以及MOF衍生物构筑的调控策略,概括了通过亚硝酸甲酯羰基化法和CO_(2)直接合成法获取DMC的进展,此外还讨论了MOF基材料在催化合成DMC中面临的挑战。

头孢替安环保工艺的研究应用

在溶剂碳酸二甲酯(一种低毒、环保性能优异的化工原料)中,7-氨基头孢烷酸(7-ACA)与1-(2-二甲基氨基乙基)-1 H-5-巯基四氮唑(MTZ)缩合生成头孢替安三位中间体7-ACMT,水解后不经分离,7-ACMT直接与.氨基噻唑乙酰氯盐酸盐(七位侧链)缩合生成头孢替安。采用一勺烩工艺合成目标产物头孢替安,简化工艺过程;优化溶剂比例和工艺条件,减少精制过程,减少有机溶媒的使用种类和数量,降低工艺成本,利于工艺环保操作控制。结果表明,工艺中使用的有机溶媒易降解毒性小,利于工艺回收利用。产品质量分数可提高到99.0%,产品色级可控制在2#以下,未知杂质质量分数可控在0.15%以下,适合产业化生产应用。

球形纳米碳酸钙的研究应用

球形纳米碳酸钙具有优异的分散性、流动性和反应活性,在新材料和大健康等领域展现出良好的发展潜力,但其合成与应用还面临诸多挑战,商品化和产业化发展滞后。本文论述了球形纳米碳酸钙的结构特征、合成方法与工艺,探讨了不同工艺方法的技术优势和发展瓶颈。最后,总结球形纳米碳酸钙在聚合物改性增韧、新材料制备、靶向医药担载等方面的应用进展,并对其亟待解决的问题进行分析。

生物质碳点的合成及应用进展

从生物质衍生碳点(BCDs)的制备和BCDs在传感器、生物医学、电气应用、食品检测等领域的应用,对国内外BCDs的研究进展进行了综述,并对其未来发展进行展望。

碳纤维复合材料在化工塔内件上的应用

随着国内新能源汽车产业的迅速崛起,用于电池电解液的碳酸二甲酯(DMC)需求强劲。采用甲醇气相氧化羰基化法生产碳酸二甲酯(DMC)的核心设备是脱轻塔,因其内部介质含有氯化氢(HCL)气体,导致原有钛材塔内件腐蚀严重,塔内件使用寿命短,严重影响碳酸二甲酯(DMC)装置的正常运行。通过采用碳纤维复合材料塔内件进行替换,设备的使用寿命大大延长,检修周期延长,应用效果良好,非常值得推广。本文阐述了碳纤维复合材料在脱轻塔内的使用情况,探讨了碳纤维复合材料塔内件的优缺点,对比了不同材料塔内件的耐腐蚀性能和成本,最后结合碳纤维复合材料产品的特点,对碳纤维复合材料在化工领域的应用进行了展望。