超声波辅助制备非晶态Ni-Mo-B催化剂及其加氢脱氧性能研究

以(NH_4)_6Mo_7O_(24)和Ni(NO_3)_2为原料,以NaBH_4作为还原剂采用常规方法和超声波法制备出非晶态Ni-Mo-B催化剂,用BET、SEM、XRD和FT-IR对所制备的催化剂进行表征.XRD结果表明,所制备的催化剂均为非晶态结构,超声波的引入抑制了硼氧化物的生成,提高了非晶态的无序性.SEM显示,引入超声波,催化剂粒径变小,催化剂的团聚现象减少,比表面积增大.以苯酚为模型化合物研究催化剂的加氢脱氧性能,其中超声波条件下制备的催化剂表现出优良的加氢脱氧活性,在498 K时,苯酚的转化率达81.08%,脱氧选择性达93.39%.     

层化法制备MoS2催化剂及其加氢脱氧性能研究

以商品MoS_2为原料,采用正丁基锂嵌入层化法制备了具有大比表面积的MoS_2催化剂,比表面积高达10.20 m~2/g。BET、XRD、SEM等表征结果表明:采用加入阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的改进层化法,能够制备出堆叠层数较少的MoS_2催化剂,而阴离子表面活性剂的加入不能促进层化效果。MoS_2催化对甲基苯酚加氢脱氧反应(HDO)的主要产物为4-甲基环己烯、甲基环己烷和甲苯。层化MoS_2催化剂中具有2个催化作用的活性位:"侧边"位(Edge)和"棱边"位(Rim),加氢脱氧反应更容易发生在"棱边"位上。层化MoS_2催化剂中加入助剂Ni或Co可以提高催化剂的加氢脱氧活性,其催化对甲基苯酚加氢脱氧反应的转化率提高幅度为10%左右,助剂Ni的引入可以促进甲苯转化为甲基环己烷,更有利于提高以生物油为原料制备燃料油的品质。总体上,加入Ni或Co的层化MoS_2催化剂,其HDO反应活性仍不高,可能是由于MoS_2本身所具有的特定结构和化学活性的有限性而决定的。     

La-Ni-Mo-B非晶态催化剂高温催化苯酚加氢脱氧及失活性能

以(NH4)6Mo24、Ni(NO3)2和La(NO3)3为原料,NaBH4为还原剂,采用化学还原法制备出非晶态催化剂La-Ni-Mo-B,以苯酚为模型化合物研究其加氢脱氧性能。结果表明,非晶态催化剂具有较高的加氢脱氧活性,而在548K时苯酚转化率降低至58.5%。主要原因是该非晶态催化剂在548K下,颗粒发生明显团聚,比表面积显著下降,非晶态Ni活性中心发生晶化,电子转移减少,抑制了催化剂的加氢活性,使反应路径偏向直接脱氧的方式进行,从而导致经过高温热处理的La-Ni-Mo-B(C)在523K时,苯酚转化率下降至37.5%,芳香烃苯的含量增加至22.3%。     

Hydrodeoxygenation of benzaldehyde and acetophenone on La-Ni（Co）-Mo-O-B amorphous catalysts

采用化学还原法制备出La-Ni-Mo-B和La-Co-Mo-B非晶态催化剂,以苯甲醛和苯乙酮为模型化合物研究了所制催化剂的加氢脱氧性能。结果表明,两种催化剂都具有非晶态结构,催化原料的转化率和脱氧率都能达到100.0%。因La-Ni-Mo-B中Ni0和B0之间存在电子转移,使其具有较高的加氢活性,脱氧后产物中的甲苯或乙苯可被进一步加氢生成相应的环烷烃,产物中的芳烃含量低,满足清洁燃油的要求。     

烷基苯酚加氢用Pd/C催化剂性能研究

采用浸渍法制备不同助剂改性的Pd/C催化剂,并与未添加助剂的Pd/C催化剂对比,考察不同助剂对苯酚加氢制备环己酮用Pd/C催化剂性能影响。结果表明,助剂Zn对催化剂活性和选择性影响较小,助剂Mg、Fe、Co使烷基苯酚加氢用Pd/C催化剂活性和选择性均有所提升,且以CoCl2为Co源,质量含量为2.0%Co修饰的Pd/C催化剂效果较优,催化剂重复使用性能良好。     

金属助催化剂对介孔Ni基催化剂加氢提质木质素的影响

制备了还原型介孔Ni基催化剂,探究了金属助剂对愈创木酚和木质素催化加氢精制的影响。结果表明,助催化剂Co的加入,有利于载体表面金属Ni组分的分散。非晶态ZS-Co催化剂在180℃,4 MPa H_2,正庚烷为溶剂的反应条件下,愈创木酚的转化率达到73.9%,其中脂肪族含氧衍生物的选择性为89.4%,原料中甲氧基和苯环加氢程度较高。乙醇中羟基与原料中含氧官能团在金属活性位点之间存在竞争关系。非晶态催化剂可以促进木质素降解产物的催化加氢反应。     

Ni-Mo-B非晶态合金催化剂制备及其催化加氢性能研究

采用化学还原法,以Ni(Ac)2.4H2O和NH4Mo9O24.4H2O为原料,KBH4为还原剂,制备了Ni-Mo-B非晶态合金催化剂。以硝基苯加氢为探针反应,考察了制备条件对Ni-Mo-B催化剂的结构和性能以及反应温度、压力与催化剂用量等反应条件对催化加氢性能的影响。研究结果表明,适当添加Mo可以提高Ni-B催化剂活性。当Mo掺杂量为Ni质量的5%时,Ni-Mo-B催化剂活性最佳。Mo主要以MoO3的形式存在,MoO3的分散作用可防止Ni-B合金粒子的团聚,提高了催化剂比表面积,稳定了Ni-Mo-B催化剂的非晶态结构。     

助剂Mo对硅柱撑蒙脱土负载镍催化剂结构及加氢脱氧性能的影响

以聚乙烯吡咯烷酮为纳米颗粒保护剂,水合联氨为还原剂,采用液相还原法制备硅柱撑蒙脱土负载型双金属催化剂Mo-Ni/SPC,通过XRD、N2吸附-脱附、HRTEM、FT-IR和XPS等研究助剂Mo添加量对催化剂结构的影响。以苯酚加氢脱氧为探针反应对Mo-Ni/SPC催化剂性能进行评价,研究催化反应的最佳工艺条件及重复使用性能。结果表明,在3 MPa和623 K条件下,Mo-Ni/SPC催化剂表现出优异的催化性能,苯酚转化率98%,环己烷选择性约95%,脱氧率100%。     

NCH6-2A型高性能辛烯醛气相加氢制辛醇催化剂制备工艺的研究

介绍了一种新型的高性能铜锌系辛烯醛气相加氢制辛醇催化剂,对催化剂的中和沉淀方式、中和温度、中和时间和助剂进行了考察,得到了最佳的制备工艺条件,并对制备的催化剂进行了活性评价。催化剂制备的最佳工艺条件为:采用正加法进行中和,控制中和温度为T3,中和时间控制在30~40 min,加入助剂,助剂含量b。活性评价结果表明:制备的高性能辛烯醛气相加氢制辛醇催化剂,其辛烯醛转化率99.98%,辛醇选择性99.90%;耐热后辛烯醛转化率99.97%,辛醇选择性99.98%,性能稳定。     

Ni-Cu-Ce-B/γ-Al_2O_3对苯酚选择性加氢制备环己酮的催化性能研究

以NiCl_2、Cu(NO_3)_2、Ce(NO_3)_3为原料,采用等体积浸渍法和KBH4还原法制备Ni-Cu-Ce-B/γ-Al_2O_3催化剂,研究了其催化苯酚选择性加氢制备环己酮的反应性能。考察了反应温度、反应压力、反应时间、液时空速、氢气/苯酚体积比、催化剂用量、不同助剂对反应活性和选择性的影响,通过正交实验筛选出了最佳的反应条件。结果表明,在反应温度为150℃、反应压力为1.0 MPa、反应时间为1.5 h、液时空速为2.0 h~(-1)、氢气/苯酚体积比为50/1时,反应活性达48.21%,反应选择性达29.16%。助剂Cu、Ce的加入和催化剂显碱性都有利于生成环己酮。     

不同结构硫化钼催化剂上酚类模型化合物的加氢脱氧

Several MoS2 catalysts of different structure, prepared by in situ decomposition of ammonium heptamolybdate （AHM） and molybdenum naphthenate （MoNaph）, and by MoS2 exfoliation （TDM）, were characterized by BET, X-ray diffraction （XRD）, Energy Dispersive X-ray （EDX） and transmission electron microscopy （TEM）. The analysis showed that MoS2 structure was dependant upon the preparation procedure. The activity of the catalysts was determined by measuring the hydrodeoxygenation （HDO） of phenol, 4-methylphenol and 4-methoxyphenol using a batch autoclave reactor operated at 2.8 MPa of hydrogen and temperatures ranging from 320-370℃. By comparing the conversion, the reactivity order of the catalysts was： AHM〉TDM-D〉MoNaph〉thermal〉MoS2 powder〉 TDM-W. Also, the effect of reaction temperature on the HDO conversion was explained in terms of equilibrium of reversible reaction kinetics. The main products of the HDO for phenolic compounds were identified by gas chromatography/mass spectrometry （GC/MS）. The results showed that the product distribution and the HDO selectivity were correlated with the reaction temperature. Two parallel reaction routes, direct hydrogenolysis and combined hydrogenation-hydrogenolysis, were confirmed by the analysis of the product distribution. High temperature favored hydrogenolysis over hydrogenation for HDO of phenol and 4-methoxyphenol, whereas for 4-methylphenol the reverse was true.     

A facile and low-cost synthesis of MoS2 for hydrodeoxygenation of phenol

MoS₂, Ni-doped MoS₂, and Ni-doped MoS₂/Al₂O₃ were synthesized by using thiourea as an organosulfur source with simple and low cost methodology to convert phenol, a model compound of lignin biomass into cyclohexane via catalytic hydrodeoxygenation (HDO). As-synthesized catalysts were characterized by X-ray diffraction, thermal gravimetric analysis, N₂ sorption, transmission electron microscopy, and X-ray absorption near-edge structure. The phenol conversion was achieved better in semi-amorphous MoS₂ than the crystalline one. In addition, all developed MoS₂ showed high selectivity toward HDO of phenol than hydrogenation of phenol, leading to ~ 90% of cyclohexane selectivity in Ni-doped MoS₂.     

Conversion of phenol to cyclohexane in the aqueous phase over Ni/zeolite bi-functional catalysts

A series of Ni/HZSM-5 and Ni/HIM-5 bi-functional catalysts were synthesized and applied to the aqueous-phase hydrodeoxygenation(HDO)of phenol.The Ni dispersibility and particle sizes were shown to be directly related to the porosity and crystal sizes of the parent zeolites,which further influenced the catalytic performances.The large pores and small crystal sizes of the parent zeolites were beneficial for dispersing Ni and forming small Ni particles,and the corresponding Ni/zeolite catalyst exhibited a higher phenol conversion and selectivity towards hydrocarbons.Importantly,the Ni/HIM-5 bi-functional catalyst exhibited a high activity(98.3%)and high selectivity for hydrocarbons(98.8%)when heated at 220°C for 1 h and is thus a new potential catalyst for the HDO of phenolics to form hydrocarbons in the aqueous phase.     

溶胶凝胶法制备PW/SiO_2负载型催化剂合成异丙基苯酚

用溶胶凝胶法制备出不同含量的磷钨酸负载到SiO2上的负载型催化剂。实验结果表明,该方法制备的催化剂对苯酚异丙醇合成异丙基苯酚有催化作用。采用氨程序升温脱附、X射线衍射对催化剂表面酸性、晶相进行表征。实验结果：不同含量的二氧化硅负载磷钨酸催化剂对苯酚转化率、异丙基苯酚的选择性有较大影响。当磷钨酸含量为SiO2的25%时苯酚转化率与异丙基苯酚选择性为最佳：分别为41.67%、62.86%。     

焙烧温度对二氧化钛催化性能的影响

采用水解与超声相结合的方法制备了催化剂二氧化钛,用于碳酸二甲酯与苯酚酯交换合成碳酸二苯酯的反应,并用XRD和FT-1R对催化剂进行了表征.焙烧温度在130℃时,二氧化钛以无定形态存在;200℃开始出现锐钛矿二氧化钛,随温度的升高,钛逐渐由四面体配位向八面体配位转变.活性随焙烧温度升高而降低,200℃时活性较好,苯酚转化...     

响应面法优化Ni-P/APO-11非晶态催化剂催化松节油加氢反应

以二异丙胺、氢氧化铝为原料,采用水热合成法制得APO-11磷酸铝分子筛。采用化学还原法制备非晶态Ni-P/APO-11催化剂用于α-蒎烯加氢反应,考察了α-蒎烯加氢反应条件,通过响应面法实现进一步优化,而后采用XRD、BET、SEM、XPS、ICP等对该催化剂进行了表征。结果显示,在反应温度124.8℃,反应压力4.9 MPa,催化剂用量6.3%,反应时间90 min时,α-蒎烯转化率为99.45%,顺式蒎烷选择性97.35%。为进一步拓宽该催化剂使用范围及提高松节油体系的深加工利用水平,将该催化剂用于松节油其他组分的加氢反应中,展现出良好的催化活性,原料转化率均可达到99%以上,选择性65%以上。     

Characterization and catalytic properties of Ni–Mo–B amorphous catalysts for phenol hydrodeoxygenation

Ni–Mo–B amorphous bimetallic catalysts were prepared by chemical reduction of nickel nitrate and ammonium heptamolybdate with sodium borohydride aqueous solution. By introducing the ultrasound, the particle size was decreased and the formation of boron oxide was inhibited. The catalyst, prepared by ultrasonic-assisted reduction, exhibited higher catalytic activity than the normal amorphous catalysts prepared via direct reduction in the phenol hydrodeoxygenation (HDO). The higher catalytic activity could be attributed to the higher contents of Mo⁴⁺ and unsaturated Ni active site.