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91.
制备方法对Ni/ZnO催化丙三醇重整-氢解性能的影响 总被引:1,自引:0,他引:1
采用浸渍法、共沉淀法、水热法和碳微球硬模板法制备了Ni/ZnO催化剂,运用X射线衍射、程序升温还原、透射电子显微镜和氢滴定等手段对其进行了表征,并用于连续固定床反应器中无外加氢气条件下的丙三醇重整-氢解反应.结果表明,在较低空速下,生成的1,2-丙二醇(1,2-PDO)易在Ni分散度较高的催化剂上进一步裂解为乙醇和气相产物;而在较高空速下,其选择性受制于中间产物丙酮醇的加氢.在优化的空速下,Ni分散度越高越有利于1,2-PDO的生成.在Ni分散度最高的Ni/ZnO催化剂上,当丙三醇质量空速为0.84h-1时,1,2-PDO选择性最高,为54.9%,丙三醇转化率为85.4%. 相似文献
92.
In situ FT-IR spectroscopy investigations of carbon nanotubes supported Co-Mo catalysts for selective hydrodesulfurization of FCC gasoline
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To better understand the nature of carbon nanotubes supported Co-Mo catalysts (Co-Mo/CNTs) for selective hydrodesulfurization (HDS) of fluid catalytic cracking (FCC) gasoline, studies are carried out using in situ Fourier transform infrared spectroscopy (FT-IR). The catalytic performances of Co-Mo/CNTs catalysts were evaluated with a mixture of cyclohexane, diisobutylene, cyclohexene, 1-octene (60 : 30 : 5 : 5, volume ratio) and thiophene (0.5%, ratio of total weight) as model compounds to simulate FCC gasoline. The HDS experimental results suggested that the HDS activity and selectivity of Co-Mo/CNTs catalysts were affected by Co/Mo ratio; the optimal Co/Mo atomic ratio is about 0.4, and the optimum reaction temperature is 260 ℃. The in situ FT-IR studies revealed that 1-octene can be completely saturated at 200 ℃. In the FT-IR spectra of diisobutylene, the characteristic absorption peak around 3081 cm^-1 for the stretching vibration peak of =C-H bond was still clear at 320 ℃ indicating that diisobutylene is difficult to be hydrogenated. As for the thiophene, no characteristic absorption peak could be found around 3092 cm^-1 and 835 cm^-1 when the reaction temperature was raised to 280 ℃, indicating that thiophene had been completely hydrodesulfurized. On the basis of FT-IR results, it can be deduced that thiophene HDS reaction occurred mainly through direct hydrogenolysis route, whereas thiophene HDS and diisobutylene hydrogenation reaction over Co-Mo/CNTs catalysts might occur on two different kinds of active sites. 相似文献
93.
Dr. Wilson D. Bailey Alexander S. Phearman Dr. Lapo Luconi Dr. Andrea Rossin Prof. Dmitry G. Yakhvarov Dr. Lucia D'Accolti Dr. Sarah E. Flowers Dr. Werner Kaminsky Prof. Richard A. Kemp Dr. Giuliano Giambastiani Prof. Karen I. Goldberg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9920-9929
The hydrogenolysis of mono- and dinuclear PdII hydroxides was investigated both experimentally and computationally. It was found that the dinuclear μ-hydroxide complexes {[(PCNR)Pd]2(μ-OH)}(OTf) (PCNH=1-[3-[(di-tert-butylphosphino)methyl]phenyl]-1H-pyrazole; PCNMe=1-[3-[(di-tert-butylphosphino)methyl]phenyl]-5-methyl-1H-pyrazole) react with H2 to form the analogous dinuclear hydride species {[(PCNR)Pd]2(μ-H)}(OTf). The dinuclear μ-hydride complexes were fully characterized, and are rare examples of structurally characterized unsupported singly bridged μ-H PdII dimers. The {[(PCNMe)Pd]2(μ-OH)}(OTf) hydrogenolysis mechanism was investigated through experiments and computations. The hydrogenolysis of the mononuclear complex (PCNH)Pd-OH resulted in a mixed ligand dinuclear species [(PCNH)Pd](μ-H)[(PCC)Pd] (PCC=a dianionic version of PCNH bound through phosphorus P, aryl C, and pyrazole C atoms) generated from initial ligand “rollover” C−H activation. Further exposure to H2 yields the bisphosphine Pd0 complex Pd[(H)PCNH]2. When the ligand was protected at the pyrazole 5-position in the (PCNMe)Pd−OH complex, no hydride formed under the same conditions; the reaction proceeded directly to the bisphosphine Pd0 complex Pd[(H)PCNMe]2. Reaction mechanisms for the hydrogenolysis of the monomeric and dimeric hydroxides are proposed. 相似文献
94.
Giuseppe BELLUSSI Andreas HAAS Sandra RABL Dominic SANTI Marco FERRARI Vincenzo CALEMMA Jens WEITKAMP 《催化学报》2012,(1):2081-2095
Perhydroindan(bicyclo[4.3.0]nonane) was converted in a flow-type apparatus under a hydrogen pressure of 5 MPa on six different catalysts,namely on a bifunctional Pd/Na,H-Beta zeolite,on Ir/Na,H-Y and Pt/Na,H-Y zeolites with a low concentration of Br?nsted acid sites,and on three catalysts containing the three noble metals on the non-acidic support silica.On the bifunctional zeolite Pd/Na,H-Beta,skeletal isomerization of perhydroindan was the primary reaction followed by opening of one naphthenic ring,the formation of open-chain nonanes in low yields of ca.6%,and hydrocracked products C8-.The carbon number distribution of the latter was volcano-shaped with no C1,C2,C7,and C8 indicating a carbocationic hydrocracking of C9 precursors with one naphthenic ring.On Ir/Na,H-Y and Pt/Na,H-Y("high-performance ring-opening catalysts"),ring opening and hydrocracking to C8-occurred by hydrogenolysis on the respective metal.Opening of the five-membered ring was found to be much faster than opening of the six-membered ring,in agreement with literature reports.The maximal selectivities of open-chain nonanes(OCNs) attained on Ir/Na,H-Y and Pt/Na,H-Y were very high,viz.49% and 54%,respectively,and significantly better than those of the open-chain decanes observed previously with decalin as model hydrocarbon.The OCNs formed on Pt/Na,H-Y were much less branched than those formed on Ir/Na,H-Y which was interpreted in terms of the different hydrogenolysis mechanisms on both metals.Valuable ancillary mechanistic information was obtained from the selectivities of perhydroindan hydroconversion on the three noble metals on silica.In contrast to Pd/silica,Ir/silica and Pt/silica gave appreciable selectivities of OCNs as well,yet the maximum values of these selectivities were lower than those obtained on the two high-performance zeolite catalysts. 相似文献
95.
MOR负载的自还原型双功能催化剂用于催化纤维素氢解制乙二醇的研究 《燃料化学学报》2016,44(10):1225-1232
以丝光沸石分子筛(MOR)为载体,以高温生物碳源分解产物H2或CO为还原剂,采用等体积浸渍法制备自还原型双功能催化剂Ni-W/MOR,不经过还原过程直接将其应用于纤维素水相氢解制备低碳乙二醇的研究。考察了催化剂的煅烧温度、活性金属含量配比对纤维素转化率和目标产物收率的影响。结果表明,催化剂的煅烧温度在773 K为宜;XRD表征结果说明,催化剂中活性金属结晶度和晶体的种类与催化剂的配比有关;TEM照片可直观地说明,采用上述方法制备的催化剂中活性金属在载体上具有较好的分散性,粒径均小于20 nm。当Ni、W含量分别为10%和15%,煅烧温度为773 K,反应条件为513 K、5.0 M Pa、2 h时低碳多元醇总收率为56.92%,其中,乙二醇收率为52.30%。 相似文献
96.
Ruppert AM Weinberg K Palkovits R 《Angewandte Chemie (International ed. in English)》2012,51(11):2564-2601
In view of the diminishing oil resources and the ongoing climate change, the use of efficient and environmentally benign technologies for the utilization of renewable resources has become indispensible. Therein, hydrogenolysis reactions offer a promising possibility for future biorefinery concepts. These reactions result in the cleavage of C-C and C-O bonds by hydrogen and allow direct access to valuable platform chemicals already integrated in today's value chains. Thus, hydrogenolysis bears the potential to bridge currently available technologies and future biomass-based refinery concepts. This Review highlights past and present developments in this field, with special emphasis on the direct utilization of cellulosic feedstocks. 相似文献
97.
98.
Upgrading pyrolysis oil over Ni/HZSM-5 by cascade reactions 总被引:1,自引:0,他引:1
99.
Back Cover: Protection Group Effects During α,γ‐Diol Lignin Stabilization Promote High‐Selectivity Monomer Production (Angew. Chem. Int. Ed. 5/2018)
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100.
自还原双功能催化剂催化木质纤维素生物质氢解制低碳多元醇的研究 《燃料化学学报》2015,43(12):1446-1453
利用生物碳源在煅烧过程中产生的还原性气体还原金属氧化物来制备自还原型双功能催化剂Ni-W/SBA-15,将其直接应用于催化木质纤维素生物质氢解制备低碳多元醇,省去了催化剂还原步骤。TG和XRD结果表明,制备过程中引入的蔗糖含量为3.0 g时,催化剂中被还原的活性金属含量最高;随着Ni含量的增加,镍粒子逐渐增大;W物种为非晶态。SEM和TEM分析表明,SBA-15均匀地负载Ni、W粒子,且粒径小、分散性好。在自还原型催化剂10%Ni-15%W/SBA-15催化作用下,在反应温度为240℃、氢压为5.0 MPa和反应时间为6 h的条件下,微晶纤维素完全转化,低碳多元醇的收率达68.14%;当以小麦秸秆粉作为反应物时,转化率为85.32%,低碳多元醇总收率为44.71%。 相似文献