共浸法制备高分散Ni/CCA催化剂及顺酐加氢性能

为获得高分散的负载型Ni基催化剂,提高催化剂加氢性能,采用共浸法制备了以炭改性Al2O3为载体(CCA)的Ni基催化剂,采用BET、XRD和H2-TPD对催化剂进行表征,以顺酐液相加氢为探针反应研究催化剂加氢性能。结果表明,通过共浸法同时引入活性组分Ni与炭助剂,经一次焙烧后即可获得活性组分Ni高度分散的负载Ni/CCA催化剂,在顺酐加氢反应中表现出高的γ-丁内酯选择性。     

助剂对Ni/SiO2催化剂1,4-丁炔二醇加氢性能的影响

通过分步浸渍法在Ni/SiO 2催化剂中分别引入Zn、Cu、La、Mo、Co金属助剂,结合N 2物理吸附-脱附、XRD、H 2-TPR和NH 3-TPD等表征手段研究金属助剂对1,4-丁炔二醇加氢性能的影响。结果发现,Mo的引入使Ni/SiO 2催化剂的初始活性大幅增加,但反应2 h后活性下降,归因于催化剂表面酸中心使催化剂积炭失活;引入Cu、La及Co后的催化剂活性较低,推测是由于催化剂表面产生强吸附氢物种,不利于1,4-丁炔二醇加氢反应进行;与其他样品相比,Zn的引入使催化剂保持了Ni/SiO 2催化剂高的1,4-丁炔二醇加氢活性,同时可有效降低产物中2-羟基四氢呋喃副产物含量,提高目标产物1,4-丁二醇收率。     

1,4-丁炔二醇选择性加氢催化剂：Pd/ZrO2及其碱金属改性

本文以Zr(OH)4焙烧所得ZrO2为载体,采用等体积浸渍法制备了负载型Pd/ZrO2和碱金属改性的Pd/M/ZrO2催化剂,通过BET、XRD、CO2-TPD、XPS和TEM对催化剂结构和性质进行了表征,并对其在1,4-丁炔二醇（BYD）选择性加氢制1,4-丁烯二醇（BED）反应中的活性、选择性和稳定性进行了研究,考察了反应气氛、碱金属改性等对其活性和稳定性的影响。结果表明1.0% Pd/ZrO2在50 ℃,2.40 MPa H2下,能够催化1,4-丁炔二醇选择性加氢生成1,4-丁烯二醇,有较高的催化活性〔0.048 molBYD/(gPd·s)〕,在BYD完全转化的条件下,BED选择性为91.2%。反应体系中引入氨,能够显著抑制催化剂加氢活性,提高BED选择性。在BYD接近完全转化时,BED选择性可达95.6%。向ZrO2载体中引入少量的碱金属（Li、Na、K、Rb、Cs）能够提高BED选择性,其中Rb的影响最为显著,BED选择性可达94.1%。     

新型催化剂Ru/NaY催化对苯二酚加氢

采用浸渍沉淀法制备了Ru/NaY、Ru/HY和Ru/C等钌催化剂,研究了其催化对苯二酚加氢制备1,4-环己二醇的活性。利用XRD和BET等手段对样品进行了表征。不同载体负载的催化剂上对苯二酚的转化率顺序为:Ru/NaYRu/HYRu/C。以Ru/NaY为催化剂,对苯二酚为原料,乙醇为溶剂,制备了1,4-环己二醇,对苯二酚的转化率99.8%。     

Ru-Fe/Al_2O_3氧化-还原性能探究

以Al_2O_3为载体,RuCl_3·xH_2O和FeCl_3·6H_2O为活性组分前驱体,采用吸附-沉淀法制备了Ru-Fe/Al_2O_3和Ru/Al_2O_3催化剂,以马来酸二甲酯加氢合成丁二酸二甲酯为探针反应,结合H_2-TPR和XRD表征技术,考察Fe改性Ru基催化剂的氧化-还原性能及催化活性。经氧化-还原循环处理后,催化剂Ru-Fe/Al_2O_3上马来酸二甲酯加氢活性高于Ru/Al_2O_3。XRD结果显示,经处理的Ru-Fe/Al_2O_3上未见金属Ru的特征衍射峰,而Ru/Al_2O_3上出现了金属Ru的特征衍射峰。结合H_2-TPR结果推断,Ru与Fe之间发生了相互作用,这种协同作用可以改善Ru/Al_2O_3催化剂的热稳定性。     

Rh/UiO-66-NH_2催化1,4-丁炔二醇加氢性能研究

采用浸渍法将Rh Cl3浸渍于Ui O-66-NH2上,用异丙醇还原,制得Rh/Ui O-66-NH2催化剂,考察了催化剂活性中心金属Rh与底物1,4-丁炔二醇(BYD)物质的量比、反应温度、H2压力、反应时间等因素对1,4-丁炔二醇加氢制备1,4-丁烯二醇的影响。结果表明,Rh/Ui O-66-NH2催化剂负载量为5%时,以甲醇作为溶剂,催化剂活性中心金属Rh与底物1,4-丁炔二醇物质的量比1∶4 000,反应温度为140℃,H2压力4 MPa,反应时间30 min时,1,4-丁炔二醇转化率99. 2%,1,4-丁烯二醇选择性90. 8%。     

Rh/UiO-66-NH_2催化1,4-丁炔二醇加氢性能研究

采用浸渍法将Rh Cl3浸渍于Ui O-66-NH2上,用异丙醇还原,制得Rh/Ui O-66-NH2催化剂,考察了催化剂活性中心金属Rh与底物1,4-丁炔二醇(BYD)物质的量比、反应温度、H2压力、反应时间等因素对1,4-丁炔二醇加氢制备1,4-丁烯二醇的影响。结果表明,Rh/Ui O-66-NH2催化剂负载量为5%时,以甲醇作为溶剂,催化剂活性中心金属Rh与底物1,4-丁炔二醇物质的量比1∶4 000,反应温度为140℃,H2压力4 MPa,反应时间30 min时,1,4-丁炔二醇转化率99. 2%,1,4-丁烯二醇选择性90. 8%。     

Pd/MIL-101(Cr)催化1,4-丁炔二醇选择性加氢反应的研究

本文采用浸渍法制备得到5%Pd/MIL-101(Cr)催化剂,利用XRD、扫描电子显微镜(SEM)等表征手段对催化剂进行表征,考察了溶剂、催化剂与底物丁炔二醇物质的量之比、反应温度、H_2压力及反应时间等因素对1,4-丁炔二醇加氢制备1,4-丁烯二醇的影响。结果表明,以甲醇作为反应溶剂,催化剂中心金属Pd与底物物质的量之比为1∶4000,反应温度为90℃、H_2压力为4.5MPa下反应25min的条件下,1,4-丁炔二醇转化率为97.6%,生成1,4-丁烯二醇选择性达到了96.3%。     

不同载体镍基催化剂对1,4-丁炔二醇加氢性能的影响

采用等体积浸渍法将Ni分别负载在USY、ZSM-5、SBA-15、Al₂O₃和SiO₂ 5种载体上制备Ni质量分数为17%的负载型镍基催化剂,以1,4-丁炔二醇(BYD)加氢制1,4-丁二醇(BDO)为探针反应考察其催化性能。通过X射线衍射、N₂吸附-脱附、H₂程序升温还原及NH₃程序升温脱附对催化剂进行表征。结果表明,在不同载体的催化剂作用下,BYD的转化率均可达到99%以上,但BDO的选择性却有很大差异;其他条件相同时,Ni/SBA-15催化剂反应5 h时BDO的选择性达到83.1%,1,4-丁烯二醇(BED)的选择性为16.6%,且2-羟基四氢呋喃(HTHF)的选择性很低,这与Ni/SBA-15具有较大的比表面积和平均孔径、较弱的酸性和良好的活性金属组分镍分散性有关。进而筛选出在低温低压条件下BYD一步加氢制备BDO的镍基催化剂Ni/SBA-15。     

高效雷尼镍催化1,4-丁炔二醇加氢制备1,4-丁二醇

通过控制加热电流强度的方法,制备了不同Ni2Al3质量分数的镍铝合金。选取高Ni2Al3质量分数的合金进行预刻蚀和二次刻蚀处理,得到两种颗粒状雷尼镍催化剂,并用于1,4-丁炔二醇（BYD）加氢制1,4-丁二醇（BDO）。结果表明,二次刻蚀法得到的雷尼镍催化BYD加氢,在140℃、5MPa压力下反应1 h,转化率可达100%,BDO收率92%;而预刻蚀雷尼镍达到相同BDO收率所需时间为3 h。采用ICP、BET、XRD、XPS、SEM等方法对催化剂进行了表征,结果表明：二次刻蚀相较预刻蚀得到的催化剂比表面积更大,达到12.83 m2/g;并且表面微观结构更粗糙,富含缺陷活性位,Ni元素质量分数达到了61.45%。此外,金属Ni的分散性提高,表面金属Al完全消失,而Al和Ni的氧化物增多,这使得催化剂表面的骨架结构更加稳定,显著提高了催化剂的催化活性。     

MCM-41 supported CuO/Bi2O3 nanoparticles as potential catalyst for 1,4-butynediol synthesis

CuO/Bi₂O₃ (CuO/Bi₂O₃/MCM-41) nanoparticles supported on MCM-41 were synthesized by a facile impregnation method. The products were characterized by nitrogen adsorption/desorption, X-ray diffraction (XRD), H₂ temperature programmed reduction (H₂-TPR) and scanning electron microscopy (SEM). XRD patterns indicated the presence of crystalline CuO and Bi₂O₃ phase for CuO/Bi₂O₃/MCM-41 catalyst. TPR results revealed CuO nanoparticles were dispersed well on MCM-41. SEM results showed that the nanoparticles were located on the MCM-41. The activity of the catalysts towards ethynylation of formaldehyde for 1,4-butynediol synthesis was evaluated at atmospheric pressure. Compared with unsupported CuO/Bi₂O₃ and commercial Cu/Bi-based catalyst, CuO/Bi₂O₃/MCM-41 catalyst showed maximum conversion (51%) and selectivity (94%) towards 1,4-butynediol. The results show that CuO/Bi₂O₃ catalysts supported on MCM-41 have potential for 1,4-butynediol synthesis in industrial application.     

预处理对Ru/Al_2O_3催化马来酸二甲酯加氢影响

采用吸附-沉淀法制备负载Ru质量分数为1.0%的Ru/Al_2O_3催化剂,以马来酸二甲酯催化加氢合成丁二酸二甲酯为探针反应,详细考察预处理条件对Ru/Al_2O_3催化剂加氢性能的影响,并对其进行XRD、TEM和H2-TPR表征。结果表明,焙烧温度越高,催化剂催化活性越低;直接还原活化所得催化剂活性高于空气中焙烧后还原活化所得催化剂。以甲醇为溶剂,在70℃和1.0 MPa条件下,直接还原活化所得Ru/Al_2O_3催化剂上马来酸二甲酯转化率达100%,丁二酸二甲酯选择性约100%。相同时间内,空气焙烧后还原活化所得Ru/Al_2O_3催化剂上马来酸二甲酯转化率接近25%,继续延长反应时间,马来酸二甲酯转化率几乎不变。经高温焙烧还原后,活性组分Ru烧结;直接还原活化后,活性组分Ru高度分散。     

Catalytic wet air oxidation of phenol and acrylic acid over Ru/C and Ru–CeO2/C catalysts

Ru/C catalysts promoted, or not, by cerium were prepared by impregnation of an active carbon (961 m² g⁻¹) with chlorine-free precursors of Ru and Ce. They were characterized by chemisorption of H₂ and of CO and by electron microscopy. TEM and H₂ chemisorption gives coherent results while CO chemisorption overestimates Ru dispersion. In Ru–Ce/C, Ce is in close contact with Ru and decreases Ru accessibility.

Catalytic wet air oxidation (CWAO) of phenol and of acrylic acid (160°C and 20 bar of O₂) was investigated over these catalysts and their performance (activity, selectivity to intermediate compounds) compared with that of a reference Ru/CeO₂ catalyst. Carbon-supported catalysts were very active for the CWAO of phenol but not for acrylic acid. Although high conversions were obtained, phenol was not totally mineralized after 3 h. It was shown that acrylic acid was more strongly adsorbed than phenol. Moreover, the number of contact points between Ru particles and CeO₂ crystallites constitutes a key parameter in these reactions. A high surface area of ceria is required to insure O₂ activation when the organic molecule is strongly adsorbed.     

SiO2网络限域CuO纳米晶的甲醛乙炔化性能研究

甲醛与乙炔缩合制取1,4-丁炔二醇是乙炔化工的重要方向。探讨铜基催化剂在甲醛乙炔化反应中的演变及催化作用机制,并开发更高效的甲醛乙炔化催化剂是一个值得科学与产业界关注的课题。本工作在前期页硅酸铜催化剂制备及甲醛乙炔化性能研究基础上,进一步通过热处理温度的调整,在焙烧温度为650℃时,构筑了限域于SiO₂网络结构中的CuO纳米晶催化剂。CuO纳米晶适宜的化学环境,使其在甲醛乙炔化反应初始阶段快速形成活性炔化亚铜,获得了1,4-丁炔二醇收率80%左右的结果,克服了页硅酸铜物种转化为炔化亚铜速率慢、诱导期长的弊端。SiO₂网络结构的限域作用也进一步抑制了活性组分的流失,在6次套用实验中1,4-丁炔二醇收率几乎不变,呈现出良好的使用稳定性。     

La0.8Ce0.2Fe0.9Ru0.1O3/TiO2催化湿式氧化降解草甘膦废水

草甘膦是种广谱除草剂,草甘膦废水产量大、可生化性差。以钙钛矿型La_0.8Ce_0.2Fe_0.9Ru_0.1O₃/TiO₂为催化剂,采用湿式氧化(WAO)和催化湿式氧化(CWAO)法对草甘膦废水进行高效降解,并对草甘膦降解机制进行研究。应用XRD和XRF对催化剂进行表征,结果表明,合成的催化剂具有钙钛矿结构,但由于Ru原子半径太大可能没有完全进入钙钛矿骨架,导致CWAO反应后有微量Ru溶出。考察反应温度对草甘膦降解的影响,并对反应过程中C、N、P产物的选择性进行分析,结果表明,提高反应温度和加入催化剂有利于提高草甘膦转化率及对CO₂和P^3-₄的选择性,但反应温度过高不利于生成N₂,因为高温下NH₃-N更容易被氧化成N^-₂和N^-₃。在实验条件下,合适的反应温度为200 ℃,反应180 min草甘膦转化率大于95%,同时对CO₂和N₂有较高的选择性,分别为54.59%和19.40%。应用计算量子化学计算草甘膦分子的净电荷分布,结果表明,WAO和CWAO中草甘膦反应的断键部位为C—C键、C—P键和C—N键,而后中间产物再进一步被氧化为CO₂、N₂、 N^-₂、N^-₃、P^3-₄等。     

Stable and efficient Ru/TiO2-ZrO2 catalysts for catalytic wet air oxidation of phenolsulfonic acid wastewater treatment

Catalytic wet air oxidation (CWAO) technology can efficiently treat organic wastewater, but the performance of existing catalysts, especially its stability, is far from industrial applications. In this study, ZrO₂ was used to modify TiO₂ support to form the stable Ru/TiO₂-ZrO₂ catalysts. It was found that the Ru/TiO₂-ZrO₂ catalysts showed excellent performance for catalytic wet air oxidation of phenolsulfonic acid wastewater. They gave high total organic carbon (TOC) conversions (>90%) and remained stable in 5 consecutive running in the Ti/Zr ratio range from 9∶1 to 7∶3. On the other hand, TOC conversion decreased from 99.1% to 65.3% in 5 consecutive cycles for the conventional Ru/TiO₂ catalyst. The characterization results of XRD, BET, XPS, H₂-TPR and ICP-OES indicated that ZrO₂ can enter the lattice of TiO₂ to form TiO₂-ZrO₂ solid solution, which prevented the transformation of TiO₂ from anatase to rutile. In addition, the modification of ZrO₂ strengthened the interaction between Ru and the support, which effectively inhibited the leaching of Ru metal. The stable support structure and good anti-loss performance are the main reasons for the excellent reaction performance of Ru/TiO₂-ZrO₂ catalyst.     

稳定高效Ru/TiO2-ZrO2催化剂处理苯酚磺酸废水

催化湿式氧化（CWAO）技术可高效处理有机废水，但现有催化剂的性能，尤其是其稳定性距工业应用还有很大差距。利用ZrO₂对TiO₂载体进行掺杂调变，研制出了具有良好稳定性的Ru/TiO₂-ZrO₂催化湿式氧化催化剂。结果表明， Ru/TiO₂催化剂在进行连续5次催化湿式氧化降解苯酚磺酸（phenolsulfonic acid，PSA）废水的反应后，总有机碳（total organic carbon，TOC）转化率由99.1%降低至65.3%；而Ru/TiO₂-ZrO₂催化剂在Ti/Zr质量比为9∶1~7∶3范围内，能表现出优良的反应性能，在连续5次反应后， TOC转化率稳定保持在90%以上。X射线仪衍射（XRD）、N₂吸脱附（BET）、X射线扫描微探针电子能谱仪（XPS）、氢气程序升温还原（H₂-TPR）和电感耦合等离子体发射光谱（ICP-OES）表征结果表明：ZrO₂能够进入TiO₂的晶格，TiO₂-ZrO₂固溶体的生成阻止了TiO₂由锐钛矿相向金红石相的转变。另外，ZrO₂的调变加强了Ru与载体的相互作用，有效抑制了活性金属Ru的流失。稳定的载体结构和良好的抗流失性能是Ru/TiO₂-ZrO₂催化剂具有优良反应性能的主要原因。     

Catalytic hydrogenation of insoluble organic matter of CS2/Acetone from coal over mesoporous HZSM-5 supported Ni and Ru

Four supported catalysts, nickel and ruthenium on a HZSM-5 support, were prepared by equal volume impregnation and in-situ decomposition of carbonyl nickel. The properties of catalysts were investigated by catalytic hydro-conversion of 2,2′-dinaphthyl ether as the model compound and extraction residue of Naomaohu lignite as the sample under an initial H₂ pressure of 5 MPa and temperature at 150 °C. According to the catalytic hydro-conversion results of the model compound, Ni−Ru/HZSM-5 exhibited the best catalytic performance. It not only activated H₂ into H···H, but also further heterolytically split H···H into immobile H^‒ attached on the acidic centers of Ni−Ru/HZSM-5 and relatively mobile H⁺. Catalytic hydro-conversion of the extraction residue from Naomaohu lignite was further examined over the optimized catalyst, Ni−Ru/HZSM-5. Detailed molecular compositions of products from the extraction residue with and without hydrogenation were characterized by Fourier transform infrared spectroscopy and gas chromatography/mass spectrometry. The analytical results showed that the oxygen-containing functional groups in products of hydrogenated extraction residue were obviously reduced after the catalytic treatment. The relative content of oxygenates in the product with catalytic treatment was 18.57% lower than that in the product without catalytic treatment.