多级孔ZSM-5负载PtNi催化木质素衍生物选择性加氢脱氧制备环烷烃的研究

通过改变微、介孔模板剂的摩尔比合成不同孔分布的多级孔ZSM-5分子筛,并采用等体积共浸渍法制备了多级孔ZSM-5分子筛负载Pt-Ni双金属催化剂,系统研究了分子筛载体中不同微、介孔分布对愈创木酚和二苯并呋喃二元混合物加氢脱氧制备环烷烃的影响。利用X射线晶体衍射（XRD）、氮气吸脱附（N₂-BET）、场发射扫描电子显微镜（SEM）和场发射透射电子显微镜（TEM）对Pt-Ni催化剂的形貌和结构进行了表征。结果表明,不加入微孔模板剂时,合成的分子筛为无定形形貌,随着微孔模板剂摩尔分数的增加,分子筛的结晶度逐渐提高且介孔体积逐渐减小;当微、介孔模板剂摩尔比为15∶5时,Pt-Ni催化剂表现出最佳的联环己烷选择性。     

费托轻组分蜡加氢异构催化剂的制备与性能评价

以Pt为活性金属、一维十元环分子筛为载体制备了Pt/ZSM-22和Pt/SAPO-11两种加氢异构催化剂,采用XRD、NH3-TPD和N2吸附-脱附手段表征催化剂的孔结构和酸性质,并以费托轻组分蜡为原料,利用固定床反应器对催化剂的加氢异构性能进行评价.结果表明,催化剂活性和选择性主要取决于催化剂的孔结构和酸性质,在达到...     

间接模板剂法合成介孔SAPO-11分子筛及其加氢异构化性能

采用水热合成法,将未焙烧的介孔材料SBA-15作为硅源合成介孔SAPO-11分子筛。利用X射线衍射、N2吸附-脱附等温曲线,BET物理吸附,NH3-TPD以及扫描电子显微镜等对分子筛的形貌和孔结构性质进行表征。将正十二烷作为原料,考察负载量为0.5%的Pt/SAPO-11分子筛催化剂的加氢异构化反应催化性能。结果表明:以未焙烧的SBA-15作为硅源制备介孔SAPO-11分子筛,介孔比表面积为77.2 m2/g以及介孔孔容为0.261 m~3/g,有效降低孔道传质阻力,酸量显著增加,活性位增多,使长链烷烃加氢异构化的选择性达到65.21%。     

级孔Pt-Ni/ZSM-5对木质素衍生物加氢脱氧性能研究

利用等体积共浸渍法制备了级孔ZSM-5分子筛负载Pt-Ni双金属催化剂,并系统研究了不同Pt/Ni比对愈创木酚和二苯并呋喃二元混合物加氢脱氧反应性能的影响。采用XRD、N₂-BET、SEM、TEM和H₂-TPR对Pt-Ni催化剂的形貌和结构进行了表征。Ni掺入量较少时（1%和3%,质量分数）,有利于促进活性金属的分散,增强Pt-Ni双金属之间的协同作用;当Ni掺入量增加到5%时,活性金属出现较严重的团聚。二元混合物加氢脱氧实验结果表明与单金属Pt/HZ-75相比,双金属Pt-Ni/ZSM-5催化剂均表现出优异的加氢脱氧催化活性,Ni的引入显著提高了反应转化速率,并提高了产物中联环己烷的选择性。随着Pt/Ni比的降低,Pt-Ni催化剂的活性逐渐增加,而联环己烷选择性先升高后降低。Pt-3Ni/HZ-75催化剂在3 MPa、260℃下表现出最佳的催化活性和联环己烷选择性,反应4 h后转化率达到100%,联环己烷选择性达到43%。     

不同硅铝比Co/ZSM-5催化剂对费托合成汽油馏分烃选择性的调控

以ZSM-5分子筛为载体,通过等体积浸渍法制备了Co/ZSM-5系列催化剂,用于费托合成反应一步法制汽油馏分烃(C_5^C_(11)烷烃)。考察了不同硅铝比(Si O_2/Al_2O_3=25,38,50,80和200)的ZSM-5分子筛对Co/ZSM-5催化剂费托合成汽油馏分选择性的影响。采用氮气物理吸附-脱附、X射线衍射、氢气程序升温还原(H_2-TPR)和氨气程序升温脱附(NH_3-TPD)等手段对载体和催化剂进行了表征,并在高压固定床反应器上对催化剂的费托合成催化性能进行了测试。结果表明,对比Co/ZSM-5(Si O_2/Al_2O_3=25,38,50和80)催化剂,Co/ZSM-5(Si O_2/Al_2O_3=200)催化剂表现出最高的汽油馏分烃类选择性,高达52.8%,这主要归功于Co/ZSM-5(Si O_2/Al_2O_3=200)催化剂上较小钴颗粒尺寸、较优的还原性能以及适量弱酸位的协同作用。分子筛的酸性为催化剂的加氢裂解转化提供活性位,促进重质烃产物发生裂解和异构等二次反应,较小的钴颗粒尺寸和较优的还原性能有利于提高C_5C_(11)烷烃)。考察了不同硅铝比(Si O_2/Al_2O_3=25,38,50,80和200)的ZSM-5分子筛对Co/ZSM-5催化剂费托合成汽油馏分选择性的影响。采用氮气物理吸附-脱附、X射线衍射、氢气程序升温还原(H_2-TPR)和氨气程序升温脱附(NH_3-TPD)等手段对载体和催化剂进行了表征,并在高压固定床反应器上对催化剂的费托合成催化性能进行了测试。结果表明,对比Co/ZSM-5(Si O_2/Al_2O_3=25,38,50和80)催化剂,Co/ZSM-5(Si O_2/Al_2O_3=200)催化剂表现出最高的汽油馏分烃类选择性,高达52.8%,这主要归功于Co/ZSM-5(Si O_2/Al_2O_3=200)催化剂上较小钴颗粒尺寸、较优的还原性能以及适量弱酸位的协同作用。分子筛的酸性为催化剂的加氢裂解转化提供活性位,促进重质烃产物发生裂解和异构等二次反应,较小的钴颗粒尺寸和较优的还原性能有利于提高C_5⁺烃选择性。     

ZSM-5分子筛固定床催化合成聚甲氧基二甲醚

通过X射线衍射（XRD）、扫描电子显微镜（SEM）、氨气程序升温脱附（NH₃-TPD）和吡啶吸附-红外光谱（Py-IR）等对不同硅铝比（SiO₂/Al₂O₃）的ZSM-5分子筛粉末催化剂进行表征。在间歇反应器中,本文对比了不同硅铝比ZSM-5分子筛粉末催化三聚甲醛和甲缩醛合成聚甲氧基二甲醚（PODE）的催化活性,结果表明硅铝比为400的ZSM-5分子筛粉末具有最高的PODE_2~8的收率和选择性。然后,采用挤条成型法,在ZSM-5分子筛粉末（SiO₂/Al₂O₃=400）中加入硅溶胶黏结剂和甲基纤维素黏结剂,制备得到ZSM-5成型催化剂,硅溶胶添加量和甲基纤维素分子量影响成型催化剂强度。采用ZSM-5成型催化剂,以固定床为反应器,反应温度和反应空速在所考察的范围内对三聚甲醛（TOX）的转化率和PODE的选择性影响较小。在85℃、压力1MPa、空速为5h^-1的条件下进行了240h催化性能考察,成型催化剂催化性能稳定,三聚甲醛的转化率高于90%,PODE_2~8的选择性达到95%以上。     

HZSM-22的粒径调控及Pt/HZSM-22的正十二烷加氢异构催化性能

通过调控合成液中的水含量,采用过饱和溶液法,在静态水热条件下合成了三种不同c轴长度的ZSM-22分子筛,对其进行了X射线衍射、扫描电子显微镜、N₂物理吸附、NH₃-程序升温脱附和吡啶吸附傅里叶变换红外光谱(Py-FTIR)表征。并以所制备的ZSM-22分子筛为酸性载体,在其上负载0.5%(质量分数)的金属Pt作为加(脱)氢活性位点,制备成Pt/ZSM-22双功能催化剂。以正十二烷为探针分子,进行正构烷烃加氢异构化反应,考察了分子筛合成液中水含量对Pt/ZSM-22催化剂加氢异构化性能的影响。结果表明,随着合成液中水含量减少,ZSM-22分子筛粒径减小。但是当水含量低到一定值时,会有方英石和ZSM-5杂晶生成。当分子筛合成液摩尔组成为SiO₂∶Al₂O₃∶K₂O∶DEA∶H₂O=1∶0.01∶0.08∶0.29∶28时,获得的HZSM-22在所合成的三种分子筛中拥有最多的中、强Br?nsted酸量以及较短的c轴长度,对应的双功能催化剂P...     

含介孔ZSM-5分子筛MoCoP/Al_2O_3催化剂的加氢脱硫反应性能研究

以含介孔ZSM-5分子筛的Al_2O_3为载体,制备了含介孔ZSM-5分子筛的Mo CoP/Al_2O_3催化剂,采用固定床微反和中试评价装置考察了催化剂的加氢脱硫活性,并通过N2吸附-脱附、吡啶吸附红外、X射线衍射(XRD)、CO原位吸附红外(CO-FTIR)等手段对载体和催化剂进行物化性质分析。结果表明,介孔ZSM-5能够提高催化剂的酸性,增加催化剂上Mo CoS活性相的数量。含介孔ZSM-5分子筛的催化剂的酸性位容易被含氮化合物占据而影响HDS活性。采用级配装填技术可以充分发挥C12-ZSM5催化剂的加氢脱硫活性,能够将硫脱除至5. 9 ng/μL,其相对脱硫活性是C-Al_2O_3催化剂的1. 47倍。     

不同硅铝比Co/ZSM-5催化剂对费托合成汽油馏分烃选择性的调控

以ZSM-5分子筛为载体,通过等体积浸渍法制备了Co/ZSM-5系列催化剂,用于费托合成反应一步法制汽油馏分烃(C_5~C_(11)烷烃)。考察了不同硅铝比(Si O_2/Al_2O_3=25,38,50,80和200)的ZSM-5分子筛对Co/ZSM-5催化剂费托合成汽油馏分选择性的影响。采用氮气物理吸附-脱附、X射线衍射、氢气程序升温还原(H_2-TPR)和氨气程序升温脱附(NH_3-TPD)等手段对载体和催化剂进行了表征,并在高压固定床反应器上对催化剂的费托合成催化性能进行了测试。结果表明,对比Co/ZSM-5(Si O_2/Al_2O_3=25,38,50和80)催化剂,Co/ZSM-5(Si O_2/Al_2O_3=200)催化剂表现出最高的汽油馏分烃类选择性,高达52.8%,这主要归功于Co/ZSM-5(Si O_2/Al_2O_3=200)催化剂上较小钴颗粒尺寸、较优的还原性能以及适量弱酸位的协同作用。分子筛的酸性为催化剂的加氢裂解转化提供活性位,促进重质烃产物发生裂解和异构等二次反应,较小的钴颗粒尺寸和较优的还原性能有利于提高C_5~+烃选择性。     

钾离子对一步法制甲硫醇钼基催化剂的影响

选用具有高比表面积的介孔分子筛SBA-15作为载体,采用等体积浸渍法制备Mo/SBA-15和KMo/SBA-15催化剂并用于一步法合成甲硫醇,并采用氮气吸脱附（BET）、X射线衍射分析（XRD）、拉曼光谱（Raman）、X射线光电子能谱分析（XPS）等进行表征,研究钾离子的添加对催化合成甲硫醇的影响。结果表明,K的添加大幅提升了Mo/SBA-15的甲硫醇选择性和CO的转化率;在高浓度H₂S环境下,KMo/SBA-15催化剂上甲硫醇选择性达到了62%,高于目前文献报道的催化剂。Raman、XPS表征结果表明,添加K的催化剂上硫化后加氢脱硫活性相MoS₂含量增多。     

Pt/ZSM-35催化长链正构生物烷烃加氢裂化/异构化制航空煤油

以生物质油加氢脱氧得到的长链正构生物烷烃为原料，考察了H-MCM-49、H-ZSM-5、H-ZSM-22和 H-ZSM-35这4种不同分子筛催化剂的物化性质及其加氢裂化/异构化制生物航空煤油的性能。在此基础上，以H-ZSM-35分子筛为载体，制备并表征了一系列低负载量（0.1%、0.2%和0.3%）的Pt/ZSM-35双功能催化剂，以长链正构生物烷烃转化率、C₉~C₁₆产物选择性、生物航空煤油收率和异正比为指标，对其加氢裂化/异构化制生物航空煤油反应性能进行了评价，并对反应工艺条件进行优化。结果表明：H-ZSM-35的强酸中心强度高、酸量大，其结构中较小的孔口和较大的球型笼使其具有一定的容烃量和较好的择形性能，0.1%~0.3% Pt负载后， Pt/ZSM-35双功能催化剂表现出很好的加氢裂化/异构化活性和选择性。采用0.1% Pt/ZSM-35双功能催化剂在反应条件为320℃、1MPa、0.7h^-1、氢油比840∶1时，长链正构生物烷烃的转化率为84.3%，生物航空煤油收率达41.1%，产物异正比为1.34。81h长运转测试结果表明，该催化剂具有很好的稳定性。     

Promoting Xylene Production in Benzene Methylation using Hierarchically Porous ZSM-5 Derived from a Modified Dry-gel Route

Methylation of benzene is an alternative low-cost route to produce xylenes, but selectivity to xylene remains low over conventional zeolitic catalysts. In this work, a combined dry-gel-conversion and s...     

Co-conversion of methanol and n-hexane into aromatics using intergrown ZSM-5/ZSM-11 as a catalyst

The conversion of n-hexane and methanol into value-added aromatic compounds is a promising method for their industrially relevant utilization. In this study, intergrown ZSM-5/ZSM-11 crystals were synthesized and their resulting catalytic performance was investigated and compared to those of the isolated ZSM-5 and ZSM-11 zeolites. The physicochemical properties of ZSM-5/ZSM-11 intergrown zeolite were analyzed using X-ray diffraction, N₂ isothermal adsorption-desorption, the temperature-programmed desorption of ammonium, scanning electron microscopy, Fourier transform infrared spectra of adsorbed pyridine, and nuclear magnetic resonance of ²⁷Al , and compared with those of the ZSM-5 and ZSM-11 zeolites. The catalytic performances of the materials were evaluated during the co-feeding reaction of methanol and n-hexane under the fixed bed conditions of 400°C, 0.5 MPa (N₂), methanol:꞉n-hexane=7꞉:3 (mass ratio), and weight hourly space velocity=1 h^–1 (methanol). Compared to the ZSM-5 and ZSM-11 zeolites, the ZSM-5/ZSM-11 zeolite exhibited the largest specific surface area, a unique crystal structure, moderate acidity, and suitable Brønsted/Lewis acid ratio. The evaluation results showed that ZSM-5/ZSM-11 catalyst exhibited better catalytic reactivity than the ZSM-5 and ZSM-11 catalysts in terms of methanol conversion rate, n-hexane conversion rate, and aromatic selectivity. The outstanding catalytic property of the intergrown ZSM-5/ZSM-11 was attributed to the enhanced diffusion associated with its unique crystal structure. The benefit of using zeolite intergrowth in the co-conversion of methanol and alkanes offers a novel route for future catalyst development.     

Hierarchical ZSM-5 catalytic performance evaluated in the selective oxidation of styrene to benzaldehyde using TBHP

Hierarchical ZSM-5 catalysts with different Si/Al ratios (20, 60 and 100) were hydrothermally synthesized. The prepared samples were studied by several techniques, including X-ray diffraction (XRD), X-ray fluorescence (XRF) analysis, Fourier transform infrared (FTIR) spectroscopy, N₂ adsorption–desorption, high resolution transmission electron microscopy (HR-TEM), high resolution scanning electron microscopy (HR-SEM), and differential scanning calorimetry (DSC) technique. The average crystallite size and crystallinity decreases with increasing Si/Al ratio, which is confirmed by XRD. FTIR analysis further confirms the formation of ZSM-5 by the presence of characteristic bending, stretching and framework vibration. The HR-TEM images showed that all the samples having disc-like nanostructures are assembled by many primary nanocrystals. The as-synthesized ZSM-5 zeolites are thermally stable, which is confirmed by DSC. The catalytic activity of ZSM-5 zeolites was evaluated in the selective oxidation of styrene using tertiary-butyl hydroperoxide (TBHP) as the oxidant. Among the catalysts, ZSM-5(60) catalyst showed significantly higher yield of benzaldehyde at optimum conditions. The catalyst was recovered and recycled three times without a significant loss in activity and selectivity.     

纳米ZSM-5在高硅铝比料液中的再生长机制及其甲醇制芳烃性能

芳烃选择性低是ZSM-5催化甲醇制芳烃反应的难点问题,调变ZSM-5酸性质是提升选择性的重要方法。本研究将SiO₂/Al₂O₃为50的纳米ZSM-5分别置于硅铝比为50、110、220、440和660的料液中继续水热生长,优化其表面酸性,以提高轻质芳烃选择性。采用X射线衍射（XRD）、透射电子显微镜（TEM）、X射线荧光光谱（XRF）、吡啶红外（Py-IR）、氨气程序升温脱附（NH₃-TPD）等手段分析所得ZSM-5形貌、织构和酸性质,研究其水热再生长规律。发现生长过程中原粉部分溶解,包围在其表面的料液先形成小晶粒,经逐步堆积完成对原粉的包覆,最终形成孔道贯通性良好的单晶。在较低硅铝比料液中样品粒径分布不均匀,然而随着料液硅铝比的增加,包覆趋向均匀且表面呈现凸起结构。二次生长显著改变了表面酸性质及芳构化性能,在硅铝比为220的料液中生长后总酸量增加到194.9μmol/g,高于原粉的169.7μmol/g。值得注意的是,催化剂表面的强酸占比由原粉的37%显著增加至53%,B/L值也由原粉的0.56增加至3.19。该酸性的变化在促进甲醇芳构化的同时,还能强化芳烃的脱烷基化而提高BTX选择性,使总芳烃选择性和BTX选择性分别由16.1%和8.2%提高到23.8%和13.5%。     

n-Hexadecane hydroisomerization over Pt/ZSM-12: role of Si/Al ratio on product distribution

The crystallization of pure ZSM-12 phase was accomplished at Si/Al ratios ranging from 45 to 120 using tetraethylammonium bromide as the structure directing agent. The obtained samples were characterized by X-ray diffraction, scanning electron microscopy, temperature programmed desorption of ammonia, and nitrogen adsorption–desorption measurements at 77 K, respectively. The well characterized samples were used to prepare Pt (0.5 wt%)/ZSM-12 hydroisomerization catalysts which were employed to perform n-hexadecane isomerization reaction. The catalysts were compared in terms of their activity, selectivity and product distribution at different conversion levels obtained through variation in temperature and residence times. Thus, obtained trend for product distribution over Pt/ZSM-12 system has been discussed in terms of framework Si/Al ratio to understand its role in determining the product selectivity. ZSM-12 with Si/Al ratio of 120 depicted the highest overall selectivity and favored mono-branching while those having Si/Al ratio of 45, 60 and 90 were found to favor mutlti-branching.     

金属改性对多环芳烃选择性开环Pt/Beta催化剂性能的影响

以离子交换法对Beta分子筛进行Mg、Ce、Ga金属改性,并制得不同金属改性的Pt/Beta催化剂。本文采用XRD、XRF、NH₃-TPD、Py-IR、H₂-O₂、TEM、H₂-TPR、H₂-TPD及XPS等手段表征了改性前后样品的物化性质,并考察了改性前后样品的多环芳烃选择性开环性能。结果表明,改性金属对B酸中心的取代效应和对L酸中心的补偿效应,可显著调控分子筛酸性位的类型与强度。改性金属可增强金属-载体强相互作用（SMSI）,一方面促进贵金属铂的分散,提高铂纳米颗粒的热稳定性;另一方面产生铂纳米颗粒向载体的电子偏移或离域,影响H₂在铂纳米颗粒上的活化与脱附。此外,金属Ga可以选择性毒化铂纳米颗粒的活性位。改性金属显著影响Pt/Beta催化剂转化甲基萘的活性、稳定性及轻芳烃选择性,金属Ga、Ce改性可显著提高催化剂的稳定性,Ga改性催化剂的轻芳烃选择性最优。     

The preparation of Fe<Superscript>3+</Superscript> ion-exchanged mesopore containing ZSM-5 molecular sieves and its high catalytic activity in the hydroxylation of phenol

A series of Fe³⁺ containing catalysts were synthesized using ion-exchange technique over hierarchically porous ZSM-5 (M-ZSM-5) and micro-mesoporous composite ZSM-5/MCM-41 (ZSM-5/MCM-41), respectively. The prepared catalysts were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, N₂ adsorption–desorption, UV–Vis spectroscopy, temperature programmed reduction and inductively coupled plasma-optical emission spectroscopy. The characterization results exhibit that the hierarchically porous ZSM-5 was synthesized with intracrystalline mesopores, while the micro-mesoporous composite ZSM-5/MCM-41 was prepared with the well-ordered mesopores. Furthermore, the results also prove that the existence of iron in the catalysts was mainly presented in the form of Fe³⁺ ions. Catalytic performances of the samples for phenol hydroxylation were compared by using H₂O₂ as oxidant. Under the optimized conditions, Fe³⁺ ion-exchanged M-ZSM-5 (Fe-M-ZSM-5) shows that a phenol conversion of 42.3% obtained with 92.5% selectivity to dihydroxybenzenes, whereas Fe³⁺ ion-exchanged ZSM-5/MCM-41 (Fe-ZSM-5/MCM-41) give 46.2% phenol conversion and 90.1% dihydroxybenzenes selectivity, which are all better than most reported results. The recyclability tests show that Fe-ZSM-5/MCM-41 with ordered mesoporous structure and bigger surface area has better anti-deactivation performance than Fe-M-ZSM-5. The excellent catalytic performances were due to the improved diffusion performance with newly created mesopores and the highly active Fe³⁺ species obtained by ion-exchange technique.     

贵金属负载型核壳结构催化剂的制备及其催化性能

以十六烷基三甲基溴化铵(CTAB)为表面活性剂,尿素为碱源,正硅酸四乙酯(TEOS)为硅源,在环己烷和正戊醇组成的微乳体系中制备了以微孔ZSM-5分子筛为核,树枝状介孔SiO_2为壳的多级孔核壳结构分子筛。考察制备温度、时间、尿素添加量以及TEOS添加量等制备条件对制备催化剂所需载体的影响,并采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和N2吸附-脱附等手段对分子筛样品进行了表征。结果表明,制备温度为100~120℃,时间为4 h,尿素与TEOS物质的量之比为1和TEOS与ZSM-5物质的量之比为0.9~1.2时,得到的核壳结构分子筛呈现出优良的单分散性、完整性以及水热稳定性。最终在树枝状介孔SiO_2壳层负载高分散贵金属Pt,得到的双功能催化剂Pt/ZSM-5@MS在催化丙酮一锅法制备甲基异丁基酮(MIBK)反应中表现出较高的活性及良好的循环使用性能。