Synthesis of 2-methylpyrazine from cyclocondensation of ethylene diamine and propylene glycol over promoted copper catalyst

2-methylpyrazine 被乙烯肼和丙烯乙二醇的催化反应在 380 掳 C 综合。氧化铝与倡导者一起支持了铜催化剂被受精方法准备，由 ICP-AES，赌注和 TPR 描绘了。结果证明除氢作用被铬倡导者的增加改进。2-methylpyrazine 的选择到达了 84.75% ，当反应物的变换也被提高时。

POLYKETONE FROM ETHYLENE WITH CARBON MONOXIDE CATALYZED BY NOVEL CATALYST SYSTEMS BASED ON COPPER WITH BIDENTATE PHOSPHORUS CHELATING LIGANDS

Copolymerization of ethylene with carbon monoxide was pertormed with Cu catalyst systems. Novel catalystsystems based on Cu (Cu(CH_3COO)_2/ligand/acid) were firstly reported for the copolymerization of ethylene with carbonmonoxide, in which the ligand was a bidentate phosphorus chelating ligand. The experimental results showed that this kindof Cu catalyst system exhibited high activity. When DPPP (1, 3-bis(diphenylphosphine)propane) and CH_3COOH were usedas ligand and acid, the corresponding catalyst system had the best activity of 108.1 g copolymer/(gCu·h). The novel Cu catalyst system had the advantages of high stability and low cost.

Catalytic combustion of methane over nano ZrO_2-supported copper-based catalysts

The nano ZrO2-supported copper-based catalysts for methane combustion were investigated by means of N2 adsorption, TEM, XRD, H2-TPR techniques and the test of methane oxidation. Two kinds of ZrO2 were used as support, one （ZrO2-1） was obtained from the commercial ZrO2 and the other （ZrO2-2） was issued from the thermal decomposition of zirconium nitrate. It was found that the CuO/ZrO2-2 catalyst was more active than CuO/ZrO2-1. N2 adsorption, H2-TPR and XRD measurements showed that larger surface area, better reduction property, presence of tetragonal ZrO2 and higher dispersion of active component for CuO/ZrO2-2 than that of CuO/ZrO2-1. These factors could be the dominating reasons for its higher activity for methane combustion.

Effect of Relative Humidity on Catalytic Combustion of Toluene over Copper Based Catalysts with Different Supports

The copper based catalysts,CuO/γ-Al2O3,CuO/γ-Al2O3-cordierite(Cord) and CuO/Cord,were prepared by impregnation method.The catalytic activity of the catalysts was tested in absence and presence of water vapor,and the catalysts were characterized.Temperature program desorption (TPD) experiments of toluene and water on the catalysts were carried out.The influence of water vapor on the activity of the catalysts was discussed.Results showed that addition of the water vapor has a significant negative effect on the catalytic activity of the catalysts.The higher the concentration of the water vapor in feed steam was,the lower the catalytic activity of the copper based catalysts became,which could be mainly ascribed to the competition of water molecules with toluene molecules for adsorption on the catalyst surfaces.TPD experiments showed that the strength of the interaction between water molecules and three catalysts followed the order:CuO/γ-Al2O3>CuO/γ-Al2O3-Cord>CuO/Cord.As a consequence of that,the degree of degradation in the catalytic activity of these three catalysts by the water vapor followed the order:CuO/γ-Al2O3>CuO/γ-Al2O3-Cord>CuO/Cord.However,the negative effect of the water vapor was reversible.

Effect of preparation methods of aluminum emulsions on catalytic performance of copper-based catalysts for methanol synthesis from syngas

Various Cu/ZnO/Al2O3 catalysts have been synthesized by different aluminum emulsions as aluminum sources and their pertormances tor methanol synthesis from syngas have been investigated. The influences of preparation methods of aluminum emulsions on physicochemical and catalytic properties of catalysts were studied by XRD, SEM, XPS,N2 adsorption-desorption techniques and methanol synthesis from syngas. The preparation methods of aluminum emulsions were found to influence the catalytic activity, CuO crystallite size, surface area and Cu0 surface area and reduction process. The results show that the catalyst CN using the aluminum source prepared by addition the ammonia into the aluminum nitrate （NP） exhibited the best catalytic performance for methanol synthesis from syngas.

Improvement of catalytic stability for CO_2 reforming of methane by copper promoted Ni-based catalyst derived from layered-double hydroxides

Copper-promoted nickel-based metal nanoparticles (NPs) with high dispersion and good thermal stability were derived from layered-double hydroxides (LDHs) precursors that were facilely developed by a co-precipitation strategy. The copper-promoted Ni-based metal NPs catalysts were investigated for methane reforming with carbon dioxide to hydrogen and syngas. A series of characterization techniques including XRD, N2adsorption and desorption, H2-TPR, XPS, CO2-TPD, TEM, TGA and in situ CH4-TPSR were utilized to determine the structure-function relationship for the obtained catalysts. The copper addition accelerated the catalyst reducibility as well as the methane activation, and made the Ni species form smaller NPs during both preparation and reaction by restricting the aggregation. However, with higher copper loading, the derived catalysts were less active during methane reforming with CO2to syngas. It was confirmed that the catalyst with 1?wt% Cu additive gave the higher catalytic activity and remained stable during long time reaction with excellent resistance to coking and to sintering. Furthermore, the mean size of metal NPs changed minimally from 6.6 to 7.9?nm even after 80?h of time on stream at temperature as high as 700?°C for this optimized catalyst. Therefore, this high dispersed anti-coking copper-promoted nickel catalyst derived from LDHs precursor could be prospective catalyst candidate for the efficient heterogeneous catalysis of sustainable CO2conversion. ? 2016 Science Press

CO Selective Oxidation in Hydrogen-Rich Gas over Copper-Series Catalysts

The performances of CO selective oxidation in hydrogen-rich gas over fourcatalytic systems of CuO/ZrO_2, CuO/MnO_2, CuO/CoO and CuO/CeO_2 were compared. The reducibility ofthese catalysts and the effect of CuO and CeO_2 molar ratio of CuO/CeO_2 catalysts on the activityof selective CO oxidation are investigated by XRD and TPR methods. The results show that thecatalysts with the exception of CuO/ZrO_2 have the interactions between CuO and CoO, CeO_2 or MnO_2,which result in a decrease in the reduction temperature. Among the catalysts studied, CuO/ZrO_2catalyst shows the lowest catalytic activity while CuO/CeO_2 catalyst exhibits the best catalyticperformance. The CuO(10%)/CeO_2 catalyst attains the highest CO conversion and selectivity at 140and 160℃. The addition of 9% H_2O in the reactant feed decreases the activity of CuO/CeO_2 catalystbut increases its CO selectivity.

Bifunctionality of Cu/ZnO catalysts for alcohol-assisted low-temperature methanol synthesis from syngas:Effect of copper content

Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.

Dynamic Kinetics of Methanol Synthesis over a Commercial Copper-Based Catalyst

Adsorption, surface reaction and process dynamics on the surface of a commercial copper-based cata-lyst for methanol synthesis from CO/CO2/H2 were systematically studied by means of temperature programmed desorption (TPD), temperature programmed surface reaction (TPSR), in-situ Fourier transform-inferred spectroecopy(FTIR) and stimulus-response techniques. As a part of results, an elementary step sequence was suggested and a group of ordinary differential equations (ODEs) for describing transient conversations relevant to all species on the catalyst surface and in the gas phase in a micro-fixed-bed reactor was derived. The values of the parameters referred to dynamic kinetics were estimated by fitting the solution of the ODEs with the transient response data obtained by the stimulus-response technique with a FTIR analyzer as an on-line detector.

Effect of copper precursors on the catalytic performance of Cu-ZSM-5 catalysts in N2O decomposition

Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5(Si/Al ratio = 15) with aqueous solutions of different Cu precursors(CuCl_2, Cu(NO_3)_2, CuSO_4, Cu(CH_3COO)_2, and ammoniacal copper(II) complex ion). After being pretreated in flowing He at 500 ℃ to form active Cu+, these catalysts exhibited quite different activities in catalytic decomposition of N_2O. CZM-AC(II)(prepared by ammoniacal copper(Ⅱ) complex ion) with 9.4 wt% Cu content was the most active among these Cu-ZSM-5 catalysts, achieving almost complete N_2O conversion at 400 ℃.CZM-CA(prepared using Cu(CH_3COO)_2 as the Cu precursor) with 2.8 wt% Cu content was the second most active catalyst among these Cu-ZSM-5 catalysts, achieving almost complete N_2O conversion at 425 ℃. CZM-CC, CZMCN, and CZM-CS prepared by using Cu Cl_2, Cu(NO_3)_2, or CuSO_4 as the Cu precursor with similar Cu contents(≈ 1.7 wt%) were the least active among these Cu-ZSM-5 catalysts, achieving ca. 90% N_2O conversion at 500 ℃.XRD, ICP, SEM, TEM, EDX-mapping, and CO-IR experiments were conducted to characterize relevant samples.The superior activity of CZM-AC(Ⅱ) can be attributed to the high contents of total Cu+and dimeric Cu+among these samples. The influence of co-fed O_2 or H_2O on the catalytic performance of typical samples was also studied.

Effect of Ceria on Structure and Thermostability of Copper-Iron-Oxide Catalyst

The solid structures and thermostabilities of Cu-Fe-O and Cu-Fe-Ce-O supported on alumina were studied by XRD, ESR, Mossbauer and TPR techniques. The studies indicate that there are Fe2CuO4, CuO and alpha-Fe2O3 phases in Cu-Fe-O with the granula of less than 13 nm. With the catalyst pretreatment temperature rising, the crystallite of Fe2CuO4 in the catalysts grows up and that of CuO disappears gradually. The presence of Ce leads to the increase of Cu2+ concentration, inhibits the crystal growth of CuO and Fe2CuO4 in the catalyst except that of Fe2O3, and eliminates the difference for reductive reaction of oxygen in Fe-O and Cu-O. At 800 degrees C, the crystal growth of Fe2O3 in Cu-Fe-Ce-O is slower than that in Cu-Fe-O, i.e., CeO2 in Cu-Fe-Ce-O inhibits the growth of Fe2O3 phase effectively, and enhances the thermostability of catalysts so as to avoid the sintering of active elements in catalysts. CeO2 promotes the reducibility of catalysts at lower temperature.

Applications of Enzyme-simulating Copper Complex Catalyst in Low-temperature Scouring/Bleaching of Cotton Knits

An enzyme-stimulating catalyst( PTL) with copper ions( Cu^(2+)) as the activation center and aminophosphonate as ligand was developed and applied in low-temperature scouring/bleaching of cotton knits. The optimal weight ratio of Cu^(2+) to aminophosphonate was 1 ∶75. Via orthodox and single-factor experiments,the most efficient formula for low-temperature scouring/bleaching was composed of 0. 4 g/L high-efficiency degreaser DM-1130,1. 5 g/L PTL,2. 0 g/L sodium hydroxide( NaOH),and 7. 0 g/L 30% hydrogen peroxide( H_2O_2). The PTL could not only increase the whiteness of cotton knits,but also remove pectin to enhance capillary effect.

Synthesis of Multifunctionalised 2-Substituted Benzimidazoles Using Copper (II) Hydroxide as Efficient Solid Catalyst

Here we demonstrate the synthesis of multifunctionalised benzimidazoles through the coupling of o-phenylenediamine with aldehydes by using Copper (II) hydroxide as an efficient solid catalyst in methanol at room temperature. The Copper (II) hydroxide solid catalyst gave better yields (80%-99%) in short reaction time (4-8 h). These commercially available cheap catalysts are more active than many reported expensive heterogeneous catalysts. Using the Copper hydroxide fresh catalyst, the yield of product 3a was 98%, while the recovered catalyst in the three subsequent cycles gave the yield of 94%, 90% and 88% respectively.

Cu(110)晶面催化还原CO_(2)制备甲酸机理的第一性原理研究

铜基催化剂是一种高效还原CO_(2)为甲酸的绿色催化剂,明确不同晶面的还原机理对催化剂的设计及开发具有重要指导意义,但Cu(110)晶面的催化机理尚不明确。采用基于密度泛函理论的第一性原理方法对Cu(110)表面的还原机理进行了研究,系统研究了不同中间产物的吸附相关性质并探讨了相关的吸附机理。吸附能结果表明,CO_(2)在Cu(110)表面无法发生化学吸附,而^(*)COOH、^(*)HCOO、HCOOH分子和H原子的最稳定吸附位点分别为长桥位点、短桥位点、顶位点和HCP位点。布居数结果表明,^(*)HCOO和HCOOH分子在吸附过程中与Cu(110)表面的Cu原子形成离子键,H原子和Cu原子之间存在氢键作用,^(*)COOH分子中的C和Cu原子形成共价键。此外,电子态密度结果表明^(*)HCOO基团和Cu原子之间形成O—Cu键,^(*)COOH基团中的C和Cu原子形成C—Cu键,HCOOH分子中的O和Cu原子形成O—Cu键。相比于^(*)COOH/Cu(110)体系,^(*)HCOO/Cu(110)吸附体系的电荷密度、电荷转移量和成键能力均较强,说明CO_(2)在Cu(110)还原过程中中间体^(*)HCOO更稳定,合成路径属于更加高效的:CO_(2)→^(*)HCOO→HCOOH路径。

助剂对球形Cu/SiO_(2)催化剂甲醇脱氢制甲酸甲酯反应性能的影响

甲醇脱氢制甲酸甲酯是实现甲醇下游产品多元化利用的绿色高效途径,使用助剂对SiO_(2)催化剂进行改性已成为提高目标产物甲酸甲酯收率的有效策略。首先通过溶胶-凝胶法制备了球形SiO_(2)负载Cu催化剂(Cu/SiO_(2)),然后采用旋蒸法引入助剂制得CuM/SiO_(2)(M=Ce或Al)催化剂,借助N2吸/脱附、扫描电子显微镜(SEM)、H_(2)-N_(2)O滴定和X射线衍射(XRD)等手段对催化剂进行了表征,并将催化剂用于甲醇脱氢制甲酸甲酯反应评价了其催化性能。结果表明,助剂可改变催化剂中活性Cu^(0)物种的含量和表面酸碱性。与Cu/SiO_(2)催化剂相比,CuCe/SiO_(2)催化剂表面Cu颗粒的分散度提高,这促进了活性物种Cu^(0)的形成,同时表面碱性位点减少,抑制了副反应发生,因而CuCe/SiO_(2)催化剂表现出最高的活性。在300℃、0.2 MPa的反应条件下,CuCe/SiO_(2)催化剂的甲醇转化率、甲酸甲酯选择性分别为29.2%、86.3%,甲酸甲酯收率为25.2%,均明显优于文献报道的Cu基催化剂。

Zn含量对于Cu-Mn-Zn/ZrO_(2)催化剂CO_(2)加氢合成甲醇性能的影响研究

通过溶胶-凝胶方法制备了一系列不同Zn含量的Cu-Mn-Zn/ZrO_(2)催化剂,并通过XRD、BET、TPR、N_(2)O吸附、XPS、TPD和in-situ DRIFTS进行了表征。结果表明,随着Zn含量增加,催化剂上CO_(2)加氢反应的活性增加。在所有样品中,Cu_(3)MnZn_(0.5)Zr_(0.5)(CMZZ-0.5)在250℃和5 MPa条件下具有最高的CO_(2)转化率(6.5%)和甲醇选择性(73.7%)。表征结果表明,Zn进入Cu_(1.5)Mn_(1.5)O_(4)尖晶石结构,形成ZnOx,导致催化剂表面羟基含量的增加,同时增加了Cu0和Cu^(α+)的含量,改善了H_(2)和CO_(2)的活化能力。此外,通过原位漫反射红外光谱研究了CO_(2)转化为甲醇的途径。

活性炭对CFC-113加氢脱氯Cu-Pd催化剂反应性能的影响

以木制炭AC-1、沥青炭AC-2为载体,制备负载Cu-Pd双组分催化剂,用于三氟三氯乙烷(CFC-113)加氢脱氯制备三氟氯乙烯(CTFE),发现两种载体催化剂均表现出较高的初始活性,但AC-2催化剂在短时间内迅速失活。化学吸附和XRD表明,AC-1催化剂具有更高的Pd分散度,Cu晶粒尺寸相对较大;XPS和TPR分析表明,AC-2催化剂表面金属还原温度低于AC-1,但后者表现出更集中的Cu物种分布。载体表面官能团的不同会导致催化剂反应性能的差异,AC-2表面较高的羧基浓度有利于Cu的吸附和分散,但Cu在反应过程中易受HCl的作用而产生物种以及价态的变化,而木制炭催化剂稳定性优于沥青炭可能与其表面较为单一、集中分布的Cu物种有关。

铜基材料电催化还原硝酸盐制氨研究进展

人类工农业活动导致环境中硝酸盐浓度升高,利用电催化技术将硝酸盐还原合成氨(NO_(3)RA)符合“双碳”政策,可达到去除硝酸盐污染和制备氨(NH_(3))的双重目的。该文综述了铜(Cu)基材料电催化硝酸盐还原的反应机理,从反应机理角度分析了不同Cu基催化材料优势性能的起源。围绕Cu单原子、单金属Cu、Cu基合金、Cu基氧化物和Cu基金属有机框架材料的大量研究实例,对不同Cu基催化材料催化NO_(3)RA反应的性能进行归纳总结。通过对Cu基材料催化NO_(3)RA反应影响因素的分析,针对目前存在的问题展开探讨,以期为未来Cu基催化剂电催化NO_(3)RA反应的开发与实际应用提供参考。

6-羟基己酸甲酯高效催化加氢制备1,6-己二醇的工艺研究

在釜式反应器内进行6-羟基己酸甲酯加氢制备1,6-己二醇的工艺研究,考察了反应温度、反应压力、催化剂质量分数和反应时间等因素对催化加氢过程的影响,并采用气相色谱仪分析监测6-羟基己酸甲酯催化加氢制备1,6-己二醇的反应进程,得到最优工艺条件:温度为200℃、压力为7 MPa、催化剂质量分数为8%、反应时间为6 h。进一步采用核磁共振氢谱和红外光谱等分析手段对产品进行结构确认,结果表明,6-羟基己酸甲酯的转化率达99%,1,6-己二醇选择性最高可达86%。

Preparation of Cerium Doped Cu/MIL-53(A1) Catalyst and Its Catalytic Activity in CO Oxidation Reaction

Metal-organic framework（MOF） material MIL-53（A1） with high thermal stability was prepared by a solvothermal method,serving as a support material of cerium doped copper catalyst（Ce-Cu）/MIL-53（A1） material for CO oxidation with high catalytic activity.The catalytic performance between the（CuCe）/MIL-53（A1） and the Cu/MIL-53（A1） catalytic material was compared to understand the catalytic behavior of the catalysts.The catalysts were characterized by thermogravimetric-differential scanning calorimetry（TGDSC）,N2 adsorption- desorption,X-ray diffraction（XRD）,and transmission electron microscopy（TEM）.The characterization results showed that MIL-53（A1） had good stability and high surface areas,the（Ce-Cu）nanoparticles on the MIL-53（A1） support was uniform.Therefore,the heterogeneous catalytic composite materials（Ce-Cu）/MIL-53（A1） catalyst exhibited much higher activity than that of the Cu/MIL- 53（A1） catalyst in CO oxidation test,with 100%conversion at 80 ℃.The results reveal that（Cu-Ce）/MIL-53（A1） is the suitable candidate for achieving low temperature and higher activity CO oxidation catalyst of MOFs.