饿钼复合氧化物表面上激光促进异丁烷选择氧化制甲基丙烯酸

用共沉淀法制备了Bi和Mo的复合氧化物固体材料,运用XRD,IR,TPD和激光促进表面反应（LSSR）技术研究了其晶体结构、表面构造、化学吸附特性和激光促进异丁烷选择氧化反应性能,结果表明：Bi-Mo-O复合氧化物含有α-Bi2Mo3O12和少量γ-Bi2MoO6晶相;其表面上存在着Lewis碱位（Mo=O和Mo-O-Bi键中的O)及Lewis酸位（Bi^3 );异丁烷的两个甲基H分别吸附在两个相邻的Lewis碱位Mo=O上,形成双位分子吸附态;在常压和200℃条件下,用一定的激光激发Mo=O键1000次,异丁烷的转化率可达11.2％,其反应产物是异丁烯、甲基丙烯醛和甲基丙烯酸,其中甲基丙烯酸的选择性为90％,根据实验结果,探讨了激光促进异丁烷选择氧化为甲基丙烯酸的表面反应机理。     

钒钼复合氧化物表面上激光促进异丁烷选择氧化制甲基丙烯酸

表面反应;钒钼复合氧化物表面上激光促进异丁烷选择氧化制甲基丙烯酸     

激光促进异丁烷选择氧化制甲基丙烯酸

用共沉淀法制备了Fe和Mo的复合氧化物.运用XRD、 IR、 TPD和LSSR技术研究了其晶体结构、表面构造、化学吸附特性和激光促进异丁烷选择氧化反应性能.结果表明: Fe-Mo-O的主体物相为Fe2(MoO4)3,并有少量的MoO3相;其表面上存在Lewis碱位(Mo=O和Mo-O-Fe键中的O)及Lewis酸位Fe3+;异丁烷的两个甲基H分别吸附在两个相邻的Lewis碱位(Mo=O)上形成双位分子吸附态;在常压和200℃条件下,用一定频率的激光激发Mo=O键1000次,异丁烷的转化率为5.8%,其反应产物是异丁烯、甲基丙烯醛和甲基丙烯酸,其中甲基丙烯酸的选择性为80%.根据实验结果,探讨了激光促进异丁烷选择氧化为甲基丙烯酸的表面反应机理.     

激光促进锂铋磷酸盐表面异丁烷选择氧化反应

用共沉淀法制备了5％Li3PO4•BiPO4固体材料.运用XRD、IR、TPD和LSSR技术研究了其晶体结构、表面构造、化学吸附特性和激光促进异丁烷选择氧化表面反应性能.结果表明,复合盐的主体晶相为简单单斜晶型的BiPO4,Li3PO4以分子分散态掺杂主体相中;其表面存在Lewis碱位P=O和P－O－Bi键中的O2－及Lewis酸位Bi3＋和Li＋;异丁烷的两个甲基中的H分别吸附在两个相邻的Lewis碱位P=O上,形成双位分子吸附态;在常压和200℃下,用一定频率的激光激发P=O键1000次,异丁烷的转化率为11.3％,甲基丙烯酸的选择性为72％.根据实验结果,探讨了激光促进异丁烷选择氧化为MAA的表面反应机理.     

锂铅磷酸盐表面上激光促进异丁烷选择氧化制甲基丙烯酸

采用共沉淀法,制备了５％Ｌｉ３ＰＯ４－Ｐｂ３（ＰＯ４）２固体材料。运用ＸＲＤ、ＩＲ、ＴＰＤ和ＬＳＳＲ技术,研究了其晶体结构、表面构造、化学吸附特性和激光促进异丁烷选择氧化的反应性能。结果表明,复合盐的主体晶相为Ｐｂ３（ＰＯ４）２,Ｌｉ３ＰＯ４以分子分散态掺杂在主体相中;其表面存在Ｌｅｗｉｓ碱位（Ｐ＝Ｏ和Ｐ－Ｏ－Ｐｂ键中的Ｏ＾２－）及Ｌｅｗｉｓ酸位、Ｐｂ＾２＋ｔ Ｌｉ＾＋;异丁烷的两个甲基中的Ｈ分别     

钼基复合氧化物在异丁烯选择氧化制甲基丙烯醛反应中的催化性能

研究了添加不同助剂对钼基复合氧化物催化剂对异丁烯选择性氧化制备甲基丙烯醛反应的影响. 结合XRD, TPR 和FTIR等表征手段对催化剂的结构进行了研究. 结果表明, 加入适量的铋能够提高催化剂的性能, 铁和钴元素能明显改变催化剂结构和表面性能, 从而提高异丁烯的转化率和甲基丙烯醛的选择性. 同时发现某种特定晶相及晶相之间的协同作用是提高催化剂性能的关键.筛选出在最佳催化剂上异丁烯的转化率为99.9%, 甲基丙烯醛的选择性为88.7%.     

异丁烷选择氧化制甲基丙烯酸杂多化合物催化剂P1.33-dMo12VaCubSbcAsdK1.5Ox／SiC的研究

采用共沉淀法制备了一系列磷钼体系多组分催化剂P1.33-dMo12VaCubSbcAsdK1.5Ox／SiC（0.0≤a，b，c，d≤0.50）。利用XRD、FTIR、DSC、ESR等方法对催化剂的结构与性质进行了研究。XRD、FTIR的研究结果表明，合成的样品为具有Keggin杂多阴离子结构的磷钼杂多化合物。DSC，ESR测试结果表明催化剂具有较好的稳定性。同时考察了催化剂组分对异丁烷催化氧化性能的影响，结果表明，适量地引入V、As、Cu、Sb都能提高MAA（甲基丙烯酸）的选择性和MAA+MAL（甲基丙烯醛）的收率。催化剂P1.13Mo12V0.25Cu0.25Sb0.25As0.2K1.5Ox／SiC在360 ℃、常压、进料组成异丁烷：空气=1∶2（mol）、空速3 600 h－1条件下，异丁烷转化率10.7％，MAA+MAL的收率为6.8％。     

激光促进Pb和Bi磷酸盐表面上异丁烷氧化脱氢反应

采用沉淀法制备了Pb₃(PO₄)₂和BiPO₄固体材料,用XRD,IR,TPD和LSSR等手段对Pb₃(PO₄)₂和BiPO₄的晶体结构、表面构造、化学吸附性能和激光促进异丁烷氧化脱氢反应性能进行了研究.结果表明,固体材料表面由Lewis碱位P＝O和P-O-M(Pb或Bi)键中的O^2-及Lewis酸位Pb²⁺或Bi³⁺构成;异丁烷分子中两个甲基中的H分别吸附在两个相邻的Lewis碱位P＝O上,形成双位分子吸附态;在常压和200℃条件下,用一定频率的激光激发固体表面P＝O键,发生异丁烷氧化脱氢反应,产物异丁烯的选择性大于95%,在激光促进表面反应体系中,激光能量的利用率主要取决于固体材料的振动结构和对反应物分子的吸附能力,反应产物的选择性主要决定于反应物分子在固体表面上的吸附态.     

镧-钼复合氧化物超细微粒催化剂结构和甲苯选择氧化催化性能

镧－钼复合氧化物超细微粒催化剂结构和甲苯选择氧化催化性能匡文兴范以宁陈开东邱金恒王镇浦＊陈懿（南京大学化学系，南京２１００９３；＊南京化工大学应化系，南京２１０００９）关键词：镧－钼复合氧化物超细微粒结构甲苯选择氧化近年来，有关甲苯选择氧化方面的文献...     

Mn对异丁烯选择氧化制甲基丙烯醛Mo-Bi-Fe-Co-Cs-K复合氧化物催化剂的促进作用及其机理

采用共沉淀法制备了系列异丁烯选择氧化制甲基丙烯醛（MAL）Mo-Bi基复合氧化物催化剂,在常压固定床流动反应体系上考察了Mn助剂及其添加方式对催化剂性能的影响,并结合对相关催化剂物相结构的表征,探讨了Mn的作用机理.研究表明,以Mn（NO3）2为前驱体将Mn引入Mo-Bi-Fe-Co-Cs-K复合氧化物可显著提高催化剂...     

Selective Oxidation of Isobutane to Methacrylic Acid over Supported V-Mo-P Based Composite Oxide Catalysts

Heteropolyacid, the most popular catalyst for the direct oxidation of isobutane, exhibits high catalytic activity, poor thermal stability and a short lifetime. Therefore, the catalyst requires further research to improve its performance. Catalysts composed of mixed oxides (V2O5, P2O5, or MoO3) supported on silica were prepared by the sol-gel method to catalyze the reaction. Results of XRD, IR, and BET corroborated that the mixed oxides were dispersed homogeneously on the surface of support. The activity of lattice oxygen in the catalysts was studied by TPR, and the chemisorption property of isobutane on the surface of the catalysts was investigated by the TPD method. H2-TPR of the catalysts revealed that the lattice oxygen of the vanadium-based catalysts is more active than that of the molybdenum-based catalysts. The redox property of V or Mo species is slightly affected by other compositions of the series catalysts. The TPD curves illustrate that there are two kinds of adsorptive species of isobutane on     

Selective Oxidation of Isobutane to Methacrylic Acid over Supported V-Mo-P Based

Heteropolyacid, the most popular catalyst for the direct oxidation of isobutane, exhibits high catalytic activity, poor thermal stability and a short lifetime. Therefore, the catalyst requires further research to improve its performance. Catalysts composed of mixed oxides (V2O5, P2O5, or MoO3) supported on silica were prepared by the sol-gel method to catalyze the reaction. Results of XRD, IR, and BET corroborated that the mixed oxides were dispersed homogeneously on the surface of support. The activity of lattice oxygen in the catalysts was studied by TPR, and the chemisorption property of isobutane on the surface of the catalysts was investigated by the TPD method. H2-TPR of the catalysts revealed that the lattice oxygen of the vanadium-based catalysts is more active than that of the molybdenum-based catalysts. The rcdox property of V or Mo species is slightly affected by other compositions of the series catalysts. The TPD curves illustrate that there are two kinds of adsorptive species of isobutane on the surface of the V and Mo based catalysts. The adsorbing species on the VMoP/SiO2 catalyst are identical to the main adsorbing species on VP/SiO2 and MoP/SiO2. The catalyst VMoP/SiO2 is more active than others in the selective oxidation of isobutane.     

Selective Oxidation of Isobutane over NH4CsFePVMoAs Heteropolycompound Catalysts

A series of NH4Cs1.5Fe0.08HxPVMo11AsαOy heteropolycompound catalysts for the selective oxidation of isobutane, having Keggin structure, were synthesized by using co-precipitation method. The catalysts were characterized by FT-IR, H2-TPR, TG-DTA, SEM and XRD. Effects of the As content,reaction time, reaction temperature and molar ratio of isobutane to oxygen in feedstock on the activity and selectivity of the catalyst were investigated. The activation energy of the catalysts was measured by kinetics researches. Results showed the introduction of Cs^ into the catalysts shortened the stable period of them and enhanced their catalytic activity for the selective oxidation of isobutane. The highest conversion of isobutane and the total selectivity to liquid products were 18.6% and 81.2%, respectively,which were obtained at 380 *(3 with a space velocity of 975h^-1 over the NH4Cs1.5Fe0.08HxPVMo11 As0.3Oy heteropolycompound catalyst. It is confirmed that completely oxidized products were controlled well.     

丙烷选择氧化用BiCeVMoO复合氧化物催化剂中Ce组分的作用

 用X射线衍射（XRD）、激光拉曼光谱（LRS）、程序升温还原（TPR）、催化剂晶格氧反应性和微反测试等手段考察了BiCeVMoO复合氧化物催化剂的组成、结构、氧化－还原性质与催化丙烷选择氧化性能．结果表明，n（Ce）／n（Ce＋Bi）≤0．15时，Ce组分可能占据BiVMoO 结构中Bi离子所处的晶格位置．催化剂对丙烷选择氧化的催化性能与Ce组分的含量密切相关，随着Ce含量的增加，丙烯醛选择性显著升高，在n（Ce）／n（Ce＋Bi）＝0．15时达极大值．随着Ce含量的进一步增加，丙烯醛选择性下降，完全氧化产物COx选择性上升．可以认为，适量Ce组分的引入提高了催化剂晶格氧物种的反应活性，从而改善了催化剂对丙烷选择氧化的催化性能．     

Mo-P-O/SiO2催化剂上的异丁烷选择氧化反应

 采用溶胶－凝胶法制备了MoO3／SiO2和Mo－P－O／SiO2催化剂，用X射线衍射、红外光谱、程序升温还原、程序升温脱附和活性评价等手段研究了催化剂的表面结构、晶格氧活泼性、化学吸附性能以及异丁烷选择氧化反应性能．结果表明，活性组分在催化剂表面分散较好；异丁烷吸附在催化剂表面Lewis碱位的MoO端氧上形成分子吸附态；MoO3／SiO2和Mo－P－O／SiO2两种催化剂对异丁烷选择氧化都有较好的选择性，将PO3－4引入到MoO3／SiO2催化剂中可提高含氧化合物的选择性     

丙烷选择氧化的铋钼复合氧化物催化剂结构和催化性能

 应用X射线衍射（XRD）,傅里叶变换激光拉曼光谱（FT－LRS）和微型催化反应装置等测试手段研究了丙烷选择氧化的Bi－Mo复合氧化物催化剂的结构和催化性能．结果表明,Bi组分是丙烷催化氧化脱氢为丙烯的主要活性组分,而丙烯醛选择性的大小与Bi－Mo复合氧化物催化剂的组成和结构密切相关．不同组成的Bi－Mo复合氧化物催化剂在丙烷转化率（～28．0％）相近的情况下,其丙烯醛选择性随Mo／（Mo＋Bi）原子比的增加先逐渐增加,在Mo／（Mo＋Bi）原子比为0．50时达极大值（～28．1％）．随Mo／（Mo＋Bi）原子比进一步增加,丙烯醛选择性又急剧下降．XRD和FT－LRS结果表明,Bi2O3和MoO3之间可形成二元Bi－Mo－O晶相固溶体,从而显著提高了催化剂对选择氧化反应的催化性能．尤其是当α－Bi2（MoO4）3和γ－Bi2MoO6两相共存时,Bi－Mo复合氧化物催化剂具有较优良的选择氧化催化性能．γ－Bi2MoO6参与了α－Bi2（MoO4）3对丙烷的选择氧化,加速了选择氧化活性氧物种的再生．     

Selective Oxidation of Isobutene over CsFeCoBiMnMoOx Mixed Oxide Catalyst

Mixed oxide catalyst Cs0.1Fe2Co6BiMnMo12Ox was prepared by the coprecipitation method.Selective oxidation of isobutene was carried out in a fixed-bed reactor over Cs0.1Fe2Co6BiMnMo12Ox.The results showed that the catalyst had high catalytic activity. Under the optimum reaction conditions(n(i-C4):n(O2)=1:2-1:4, space velocity=180 h^-1, T=360℃), the yields of methacrolein and methacrylic acid can reach 80% and 8%, respectively. The total yield of liquid products (methacrolein, methacrylic acid and acetic acid) can reach about 90%.