Mn/Ti-Zr复合氧化物催化苯甲酸甲酯选择性加氢

以硝酸锆和钛酸四丁酯为原料,采用共沉淀法制备Ti-Zr-O氧化物载体,采用浸渍法制备了Mn/Ti-Zr催化剂;采用XRD、N2物理吸附、H2-TPR、NH3-TPD和TG-DTA对Mn/Ti-Zr催化剂进行了表征,并考察了催化剂组成、结构和反应条件对苯甲酸甲酯（MB）加氢性能的影响,以及催化剂的长周期稳定性、失活和再生行为。结果表明：TiO2含量和Mn负载量分别为12% 和8% （二者均以Ti-Zr-O氧化物的质量为基准,下同）时制备的Mn/Ti-Zr催化剂性能最优,该催化剂在θ = 390 ℃, p = 1.0 MPa,n(H2)∶n(MB) = 9∶1和重时空速（WHSV）= 0.5 h-1的优化条件能够实现98.0% 的苯甲酸甲酯转化率和89.7%的苯甲醛和苯甲醇选择性;苯甲酸甲酯加氢反应的活性和选择性分别与Mn/Ti-Zr表面MnOx物种的氧化还原性和催化剂的酸性密切相关。此外,Mn/Ti-Zr催化剂具有良好的结构稳定性,在反应1000 h后仅因积碳而丧失11% 的活性,且轻微失活的催化剂可以通过焙烧恢复其初始活性和选择性。     

Ru/CN催化对苯二甲酸二甲酯加氢制备1,4-环己烷二甲酸二甲酯

通过超声辅助NaBH4还原法制备了3%Ru/CN催化剂（Ru的质量分数）,该催化剂用于对苯二甲酸二甲酯（DMT）加氢制备1,4-环己烷二甲酸二甲酯（DMCD）。采用Raman、SEM、TEM、N2吸脱附、XRD、XPS等对载体和催化剂的组成、表面性质进行表征,结果表明,氮元素成功掺入碳骨架中且氮掺杂碳材料为介孔结构。研究了催化剂的用量、反应温度、H2 压力、反应时间等对催化剂加氢性能的影响。结果表明,当反应物用量为1.00 g,催化剂（含载体）用量为0.05 g,反应温度140 ℃,反应压力5.0 MPa,反应时间1 h时,DMT转化率为100%,DMCD选择性为99.3%。3%Ru/CN-1000催化剂循环使用5次后,催化剂催化性能未见明显下降,DMT转化率为98.8%,DMCD选择性为99.7%。     

重芳烃轻质化催化剂n（Ni）/n（Ni+Mo）的优化与分析

以β分子筛为载体,在保持金属总负载量不变的情况下,采用等体积浸渍法制备了4种不同n（Ni）/n（Ni+Mo）的催化剂。分别采用X射线衍射（XRD）、比表面积测试（BET）、氨程序升温脱附（NH₃-TPD）、氢程序升温还原（H₂-TPR）、氢程序升温脱附（H₂-TPD）和热重-差热分析（TG-DTG）等方法对催化剂进行了表征。结果表明,4种催化剂的酸量和酸强度相近,在n（Ni）/n（Ni+Mo）等于基准+0.2时,Mo与载体之间的相互作用最弱,其氢气吸附量最多且积炭量最少;采用某炼厂重整C₁₀⁺ 重芳烃对4种催化剂进行评价,结果表明n（Ni）/n（Ni+Mo）等于基准+0.2催化剂具有最优的催化活性和稳定性。上述结果表明,影响重芳烃轻质化催化剂活性和稳定性的关键因素是催化剂氢气吸附量的多少,氢气吸附量越多金属表面的溢流氢效应越明显,积炭前驱体被溢流氢及时消除,从而保护了催化剂的加氢活性中心不被积炭覆盖,有助于催化剂在较高活性下保持稳定。     

Ni/W比对NiWCx催化剂加氢性能的影响

过渡金属碳化物具有类似贵金属的电子结构和加氢性能。采用等体积浸渍法制备了不同Ni/W比的NiW/γ-Al₂O₃催化剂,以程序升温碳化法转化为NiW碳化物后对芳烃模型化合物和低温煤焦油中分离所得芳烃组分进行加氢处理。催化剂的N₂吸附、XRD、H₂-TPR和SEM表征表明,Ni的添加促进了载体表面WO₃物种的分散和还原,抑制了WO₃晶体的团聚和大晶粒的生成。萘的加氢实验表明,Ni/W原子比为0.6时催化剂的活性最佳,而添加苯酚和吡啶后的模型油加氢过程中萘的转化率和十氢萘的产率均明显下降,Ni/W原子比为0.47和0.6的催化剂性能相近,煤焦油中芳烃组分加氢后Ni/W原子比为0.47的催化剂性能更优。结果表明,Ni和W均具有良好的加氢活性,但Ni耐杂原子性能较差,二者存在一个最佳的配比以使加氢性能更优。有杂原子化合物存在时,如煤基芳烃组分的加氢,Ni/W原子比为0.47的NiW碳化物催化剂具有更好的加氢性能。     

氢处理技术在钛合金中的应用

氢处理工艺是钛合金的一种特有的热处理方式，用于改善铸造、锻造钛合金件以及粉末冶金件的组织和性能。本文综述了氢处理在钛合金中的一些应用，主要介绍了国外的研究动向。     

不饱和油脂加氢催化剂的研究

以Al₂O₃、硅藻土为载体，NiO或甲酸镍为活性组分前驱体，采用不同的沉淀法工艺制备了负载型单元镍催化剂，在相同的条件下进行活性评价。研究表明，以NiO为活性组分前驱体要优于甲酸镍，沉淀过程中反加中和优于正加中和。     

白油加氢装置技术改造

对抚顺石油化工分公司石化三厂白油加氢装置进行技术改造，通过调整加氢工艺，采用一段加氢工艺生产高品级的加氢尾油，再经分馏系统生产出多种优级品的白油，满足了市场需求，并创造了可观的经济效益和社会效益。     

Interpretation of hydrogenation kinetics of spent oil distillate from u.v. spectroscopy

Hydrotreatment of spent oil distillate was carried out on a commercial Ni-Mo-alumina catalyst in the temperature range 260–340 °C, with a liquid hourly space velocity (LHSV) of 0.7–2.0 h^?1, pressure of 4.5 MPa and $\text{H}{}_2\text{oil}$ ratio of 300 NL L^?1 (normal litre of H₂ per litre of feedstock). U.v. spectra of hydrogenated and original spent oil distillates (measured in normal hexane) gave a band with a maximum at 230 nm. The change in absorbance at three selected wavelengths for original oil distillate and hydrotreated oil at different operating conditions was taken as a guide for the determination of hydrogenation reaction rates (including partial saturation of aromatics and sulphur compound hydrogenolysis). The rate constants of hydrogenation reactions (k) using a second-order equation and a model of two parallel first-order reactions (k₁ and k₂) were calculated. Finally, the apparent activation energy (E_a), enthalpy of activation ($\text{ΔH}{}^1$) and entropy ($\text{ΔS}{}^1$) were calculated based on the values of k, k₁, and k₂. The calculated values of E_a based on k, k₁ and k₂ were 81.479, 71.188 and 62.882 kJ mol^?1, respectively. The values of $\text{ΔH}{}^1$ based on the same rate constants were 76.670, 66.564 and 58.433 kJ mol^?1, while the values of $\text{ΔS}{}^1$ were ?117.150, ?133.779 and ?150.823 J mol^?1 K^?1, respectively.     

Reactant induced restructuring and corrosion of germanium-palladium catalysts during hydrogenation reactions

An anomalous rate enhancement with increasing conversion has been observed during the liquid phase hydrogenation of nitrobenzene and crotonaldehyde over Ge/Pd/C catalysts at ambient temperature and atmospheric pressure. Inductive coupled plasma atomic emission spectroscopy and electrochemical measurement of the oxidation state of catalysts during reaction revealed that the bimetallic particles were partially oxidized by the reactants, which resulted in Ge-dissolution and increased exposure of Pd on the surface. It is proposed that the surface and bulk composition of Ge/Pd catalysts are a function of their oxidation state. This behaviour is due to the unusually high mobility of Ge in the Pd lattice and to the good solubility of GeO₂ in polar solvents. The influence of hydrogen transport on the corrosion process and the stability of other X/Pd type bimetallic catalysts during liquid phase hydrogenation are also discussed.     

Supported Molybdenum Carbides Lie Between Metallic and Sulfided Catalysts for Deep HDS

Hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene on alumina-supported Mo₂C has been studied. These catalysts are stable and active under deep HDS conditions (0-250 wt ppm S). However, although they are well known to have hydrogenation properties, they lead preferentially to a non-hydrogenated product of the HDS reaction: dimethylbiphenyl. For the same reaction, supported platinum and sulfided molybdenum oxide lead to the hydrogenated products dimethyldicyclohexyl and methylcyclohexyltoluene, respectively. The ranking of HDS activity is as follows: MoS₂/Al₂O₃ < Mo₂C/Al₂O₃ < Pt/SiO₂.