金属含量对Ni-Pd/H-Y上正癸烷加氢异构化反应活性和产物选择性的影响（英文）

在Y分子筛上浸渍0.1 wt%Pd和0.1–0.5 wt%Ni,用X射线衍射表征了该催化剂的结晶度,用透射电镜测得平均金属粒径.催化剂中Pd和Ni的化学态用X射线光电子能谱测定,其酸性则用氨-程序升温脱附进行了表征,发现一些酸位被Ni~(2+)离子交换.采用程序升温还原表征了HY分子筛负载的Pd,Ni和Pd-Ni催化剂的还原性能.正癸烷加氢异构化反应在200–450℃和1 atm条件下进行.结果发现,当0.1 wt%Pd/HY中Ni添加量增至0.3 wt%时,正癸烷转化率和异构化选择性增加.单支链和双支链异构体选择性的增加表明该反应遵循质子化环丙烷中间体机理.Ni添加量超过阈值导致活性和异构化选择性急剧下降.综上可见,双金属催化剂更有利于选择性生成双支链异构体,其辛烷值更高.     

纳米孔Pt-(Re,Sn)/HZSM5-HMS催化剂上正庚烷异构化反应的实验和动力学研究（英文）

在200–350°C考察了Pt-(Sn,Re)/HZSM 5-HMS催化剂上正庚烷异构化反应.采用X射线衍射、X射线荧光光谱、傅里叶变换红外光谱、紫外-可见光谱、H2程序升温还原、NH_3程序升温脱附、吸附吡啶红外光谱、H_2化学吸附、N_2吸附-脱附、扫描电镜和热重等技术对催化剂进行了表征.在不同的H_2和正庚烷分压条件下考察了正庚烷异构化反应动力学,研究了反应条件对催化性能的影响.结果表明,双金属催化剂和三金属催化剂表现出比单金属催化剂更高的催化性能.200 oC时Pt-Sn/HZSM 5-HMS催化剂表现出最高的异庚烷选择性(74%)和多支链异构体选择性(40%).     

纳米孔Pt-(Re,Sn)/HZSM5-HMS催化剂上正庚烷异构化反应的实验和动力学研究

在200-350℃考察了Pt-(Sn,Re)/HZSM5-HMS催化剂上正庚烷异构化反应.采用X射线衍射、X射线荧光光谱、傅里叶变换红外光谱、紫外-可见光谱、H2程序升温还原、NH3程序升温脱附、吸附吡啶红外光谱、H2化学吸附、N2吸附-脱附、扫描电镜和热重等技术对催化剂进行了表征.在不同的H2和正庚烷分压条件下考察了正庚烷异构化反应动力学,研究了反应条件对催化性能的影响.结果表明,双金属催化剂和三金属催化剂表现出比单金属催化剂更高的催化性能.200℃时Pt-Sn/HZSM5-HMS催化剂表现出最高的异庚烷选择性(＞74％)和多支链异构体选择性(40％).     

硅烷化处理对Pt/SAPO-11催化正十二烷临氢异构化反应性能的影响

 利用X射线衍射、N2物理吸附与NH3-程序升温脱附等手段以及异辛烷加氢裂化探针反应研究了硅烷化处理对Pt/SAPO-11催化剂结构和酸性的影响, 并考察了催化剂对正十二烷临氢异构化反应的催化性能. 结果表明,硅烷化处理有效清除了样品外表面的酸性位,减少了发生在外表面的非选择性裂化反应. 硅烷化处理后,催化剂对单支链异构体的选择性明显提高,尤其对单支链端甲基异构体的选择性显著提高,但催化剂的总体异构化选择性有所降低. 硅烷化处理可能造成催化剂的孔口窄化,从而提高单支链异构体的选择性,但同时也导致其微孔孔道内裂化反应的增多.     

Ni对Pd/Al2O3密偶催化剂催化性能的影响

考察了助剂Ni对以改性氧化铝为载体的单Pd密偶催化剂的影响.结果表明,掺杂Ni可以明显改善对C3H8的催化性能,尤其对老化催化剂效果显著.此外, Ni的添加使老化催化剂Pd/Al2O3的起燃温度(T50)和完全转化温度(T90)分别降低31和30oC.单反应测试结果表明,添加Ni能明显提高对C3H8+ NO反应的催化性能.采用H2程序升温还原、CO吸附、高倍透射电镜和X射线光电子能谱等手段对新鲜和老化催化剂进行了表征.结果表明,掺杂Ni不仅可以抑制活性组分PdOx的烧结,减少金属态Pd0的产生,而且可以提高PdOx物种的可还原能力和有效比表面积.     

Ni对Pt/SAPO-11催化剂物化及异构性能影响

通过浸渍法制备了Pt/SAPO-11催化剂,分步浸渍法制备了Ni-Pt/SAPO-11双金属催化剂。通过X射线衍射、低温氮物理吸附、氨程序升温脱附和吡啶吸附红外等手段对所得样品进行了表征。结果表明,助剂Ni的引入导致了催化剂的比表面积和孔容降低,同时,催化剂的B酸量、L酸量及总酸量均有所下降。在340℃时对正庚烷的临氢异构化反应中,当Pt含量0.2wt%时,Pt/SAPO-11催化剂的正庚烷转化率为45%,C7异构体收率为43%;而当Pt含量0.2wt%,同时Ni含量为0.2wt%时,Ni-Pt/SAPO-11催化剂的正庚烷转化率提高至72%,C7异构体收率提高至60%。     

Ni对Pd/Al_2O_3密偶催化剂催化性能的影响（英文）

考察了助剂Ni对以改性氧化铝为载体的单Pd密偶催化剂的影响.结果表明,掺杂Ni可以明显改善对C3H8的催化性能,尤其对老化催化剂效果显著.此外,Ni的添加使老化催化剂Pd/Al2O3的起燃温度(T50)和完全转化温度(T90)分别降低31和30 oC.单反应测试结果表明,添加Ni能明显提高对C3H8+NO反应的催化性能.采用H2程序升温还原、CO吸附、高倍透射电镜和X射线光电子能谱等手段对新鲜和老化催化剂进行了表征.结果表明,掺杂Ni不仅可以抑制活性组分PdO x的烧结,减少金属态Pd0的产生,而且可以提高PdO x物种的可还原能力和有效比表面积.     

聚乙二醇辅助溶胶-凝胶法制备Cu-Zn-Al双功能催化剂的结构和催化性能

在聚乙二醇(PEG)辅助下,用溶胶-凝胶法制备了一系列Cu-Zn-Al双功能催化剂,采用X射线粉末衍射、N2吸附、X射线光电子能谱、H2程序升温还原和NH3程序升温脱附等方法对催化剂进行了表征,并将催化剂用于浆态床合成气一步法制二甲醚反应中,考察了PEG用量对催化剂性能的影响.结果表明,PEG的添加可改善催化剂的织构性...     

Ni/HZSM-5催化剂的结构及其催化山梨醇水相加氢合成烷烃性能

采用浸渍法制备了Ni/HZSM-5双功能催化剂,考察了焙烧温度对催化剂结构及其催化山梨醇水相加氢合成C5～C6烷烃性能的影响.结果表明,在金属中心和酸性载体的协同作用下,通过山梨醇中C-O键加氢和异构化高选择性合成了C5～C6烷烃.经500°C焙烧的Ni/HZSM-5催化剂上山梨醇水相加氢的活性最高,山梨醇转化率为62.0%,戊烷和己烷的总选择性为76.4%,其中异己烷选择性达45.4%.对催化剂进行N2物理吸附、X射线衍射、NH3程序升温脱附和H2程序升温还原等表征后发现,经500°C焙烧催化剂的有效比表面积和孔体积均明显增大,HZSM-5负载的硝酸镍分解成较小晶粒的NiO,表面酸量适中,且Ni物种与载体相互作用较强,较易被H2还原,Ni还原度达100%.这是其催化活性最高的原因.     

丙烷选择氧化催化剂Mo-V-Zr-O的研究

研究了Zr添加量对Mo-V-O基催化剂丙烷选择氧化制丙烯醛催化性能的影响.对催化剂的BET、X射线衍射、H2-程序升温还原、NH3-程序升温脱附和异丙醇分解表征结果表明,Zr的添加改变了催化剂的物相结构、氧化还原性和酸碱性质,从而影响催化剂的催化性能,其中Mo2VZr0.5Ox催化剂表现出较好的催化活性和丙烯醛选择性.     

Catalytic Influence of Bimetallic Bifunctional Ni-Pd/H-β and H-Mordenite Nanoporous Catalysts for Hydroisomerisation of <Emphasis Type="Italic">n</Emphasis>-Octane

Zeolite-β and mordenite were impregnated with 0.1 wt% Pd and varying the amount (0.1–0.5 wt%) of Ni. The prepared nanoporous catalyst were characterized by various physico-chemical techniques such as XRD, nitrogen adsorption–desorption isotherm (BET), NH₃-TPD and TPR, XPS and TEM. Hydroisomerisation of n-octane was carried out in the temperature range from 200 to 450 °C in the presence of flowing H₂ gas under 1 atm. Finally we found that Ni addition up to 0.3 and 0.2 wt% over 0.1 wt% Pd/H-β and H-mordenite enhances the n-octane conversion and isomerisation selectivity. As the Ni amount exceeds the threshold values, the conversion decreases with increase in cracked products, and also, the selectivity of mono and dibranched isomers were improved suggestion operation of PCP intermediate mechanism. The bimetallic catalysts were more selective to the formation of dibranched isomers with higher octane number, when compared with monometallic catalysts. Ni-Pd loaded zeolite-β supports always show higher activity and selectivity than mordenite supports. Moreover, we achieved higher conversion (74.9 %) and isomerisation selectivity (92.5 %) at low Ni loading (0.3 Ni wt% over 0.1 Pd wt%/Hβ) for the first time.     

Selective hydroisomerization of n-dodecane over platinum supported on zeolites

In this study, in order to develop catalysts for the selective isomerization of higher paraffin, the hydroisomerization reaction of n-dodecane was performed as a model reaction. Pt/ZSM-48, Pt/HZSM-5, Pt/HY, and Pt/SAPO-11 were examined for the selective hydroisomerization of n-dodecane. The catalysts were characterized via X-ray powder diffraction, N₂ adsorption, and the temperature-programmed desorption of ammonia. Among the catalysts studied, the Pt/HZSM-48 catalyst exhibited the best isomerization selectivity in the hydroisomerization reaction of n-dodecane, which is attributed to the moderate acid sites and medium-sized pores present in the HZSM-48. The highest iso-dodecane yield was obtained at a reaction temperature of 280 °C in the Pt/HZSM-48 catalyst. The optimal selectivity of the n-dodecane hydroisomerization over the Pt/SAPO-11 catalyst was obtained at approximately 300 °C, which was slightly higher than that of the Pt/HZSM-48 catalyst.     

Impact of the Spatial Organization of Bifunctional Metal–Zeolite Catalysts on the Hydroisomerization of Light Alkanes

Improving product selectivity by controlling the spatial organization of functional sites at the nanoscale is a critical challenge in bifunctional catalysis. We present a series of composite bifunctional catalysts consisting of one‐dimensional zeolites (ZSM‐22 and mordenite) and a γ‐alumina binder, with platinum particles controllably deposited either on the alumina binder or inside the zeolite crystals. The hydroisomerization of n‐heptane demonstrates that the catalysts with platinum particles on the binder, which separates platinum and acid sites at the nanoscale, leads to a higher yield of desired isomers than catalysts with platinum particles inside the zeolite crystals. Platinum particles within the zeolite crystals impose pronounced diffusion limitations on reaction intermediates, which leads to secondary cracking reactions, especially for catalysts with narrow micropores or large zeolite crystals. These findings extend the understanding of the “intimacy criterion” for the rational design of bifunctional catalysts for the conversion of low‐molecular‐weight reactants.     

正庚烷在β沸石负载的磷钨杂多酸催化剂上加氢异构化

制备了系列含微量Pt（0．4％）的负载型磷钨杂多酸（PW）催化剂，采用Hβ或通过水热和盐酸联合脱铝的Hβ沸石作为催化剂载体，并在微型常压固定床催化反应器上考察了所制备的催化剂在正庚烷临氢异构化反应中的催化性能。结果表明，Pt及PW能够高度分散在催化剂载体表面；PW负载量及载体的水热处理温度和时间都显著影响催化剂的转化率和选择性，与未负载杂多酸的催化剂相比，负载杂多酸后的催化剂的正庚烷转化率有大幅度提高，异构化产物有所下降，但仍保持较高的异构化选择性。     

HZSM-5/Hβ复合分子筛的正辛烷临氢异构化和芳构化性能

将不同孔尺寸、酸强度的HZSM 5和Hβ分子筛混合制得复合载体,担载金属组分Ni、Mg、Mo、Zn制得烷烃异构化和芳构化催化剂M/C。采用XRD、BET、程序升温氨脱附（NH3 TPD）及吡啶吸附 脱附红外光谱法对制备的载体及催化剂进行了理化性质表征。以正辛烷为正构烷烃模型化合物,在连续加氢微型反应装置上评价了催化剂对正构烷烃异构化和芳构化反应的催化性能。结果表明,与单一分子筛相比,复合后载体的表面酸中心分布得到了调节,中强酸中心的增加有利于烷烃异构化和芳构化反应。复合分子筛催化剂引入不同金属组分进行改性后体现出不同的催化性能,其中Ni的引入既提供了加脱氢活性中心,又获得了适宜的B、L酸中心分布,使反应转化率和选择性显著提高。反应条件对催化剂的异构化和芳构化性能也有不同程度的影响,在320℃、2.8MPa、2.0h－1下,正辛烷的临氢异构化和芳构化选择性较好。     

Synthesis of adamantane on zeolite catalysts

The synthesis of adamantane from tetrahydrodicyclopentadiene on zeolites with different framework structures was studied. The adamantane yield on HY zeolites is higher than on HM and HZSM-5 zeolites. Among various types of dealuminated HY zeolites the HEY and HUSY zeolites give higher adamantane yields than conventional HY zeolite. The changes in activity and selectivity of the main and side reactions are correlated with the acidity and the pore structure of the zeolites. To ion-exchange the HY and HUSY zeolites with Ni2+ and La3+ cations may further improve the activity and selectivity of the zeolite catalysts.     

模板剂种类对ZSM-22分子筛的酸性和正癸烷加氢异构化催化反应性能的影响

分别以1,6-己二胺和1-乙基溴化吡啶为模板剂,采用静态晶化法合成了不同硅铝比的ZSM-22分子筛;采用XRD、XRF、N₂物理吸附、SEM、NH₃-TPD和Py-IR等手段对分子筛的结构和酸性进行了表征;采用浸渍法制备了0.5%Pd/ZSM-22双功能催化剂,对金属Pd的分散度用H₂化学吸附进行表征,并在微型固定床反应器上考察了该催化剂对正癸烷加氢异构化反应的催化性能。结果表明,模板剂种类显著影响ZSM-22分子筛的结构和酸性,以DAH为模板剂合成的ZSM-22分子筛晶粒粒径小,异构化产物从分子筛孔道内扩散的程距更短,而且具有更高的B/L值和相对温和的酸性,在正癸烷加氢异构化反应中,金属位与分子筛的酸性位实现协同催化作用,具有更高的催化活性和异构化选择性。     

磷铝系列分子筛催化剂的制备、表征及催化丁烷转化反应的研究

 合成了AlPO－11,SAPO－11及其含杂原子Co或Mn的磷铝系列分子筛．XRD结果证实,合成产物均具有AEL分子筛晶体结构．用X射线荧光光谱测定了晶体的元素组成,并用NH3－TPD考察了样品的酸性和酸分布．在以合成的分子筛为基质所制备的催化剂上进行了丁烷异构化和一步异构脱氢反应．结果表明,载0．3％Pd的SAPO－11分子筛催化剂具有最高的丁烷异构化选择性,而在丁烷一步异构脱氢反应中,含金属杂原子的催化剂具有更高的异丁烯选择性．     

由酸活化高岭土制备多级纳米孔HY分子筛及其表征

由酸活化的高岭土制备了多级纳米孔HY分子筛。通过改变老化时间和晶化时间可得到最大的多级因子(HF),此时外比表面积最大而微孔孔体积变化不大。运用X射线衍射(XRD)、X射线荧光光谱、N2吸附-脱附法和NH3程序升温脱附对所得样品进行了表征。老化2 d和晶化24 h所制的纳米孔HY分子筛样品的HF值最大。样品的酸性和结晶度也随着制备条件而变化。另外,适量NaCl的嵌入对提高对所制样品的HF值、酸性和结晶度起到重要作用。通过比较样品和常规HY分子筛的XRD峰强度算得样品的结晶度。结果表明,优化合成条件可得到广泛适用于工业化的分子筛制备路线。     

Usy supported Pt-bearing SO42?/ZrO2 catalysts promoted by Cr for hydroisomerization of n -heptane

The Pt-bearing SO₄ ²⁻/ZrO₂ catalysts doped with Cr and supported on USY zeolite were prepared by impregnation, and characterized by XRD and IR spectroscopy of pyridine adsorption. Their catalytic activities were evaluated in the hydroisomerization of n-heptane with a fixed-bed atmospheric reactor. The Cr-promoted catalysts exhibited much higher catalytic activity and selectivity for isomerization products than the catalysts without the Cr dopant. Both the conversion and selectivity were discussed in relation with the physicochemical properties of catalysts.