钛硅分子筛催化丙烯环氧化工艺研究

以钛硅分子筛TS-2为催化剂,过氧化氢为氧化剂,甲醇为溶剂,研究TS-2催化剂催化丙烯生成环氧丙烷.考察了停留时间、反应温度、反应压力和催化剂用量对环氧丙烷收率和选择性的影响.实验结果表明,合适的反应条件为50℃,0.30 MPa,催化剂用量为反应物质量的3.44%,停留时间90 min.在该条件下反应,过氧化氢的平均转化率和环氧丙烷的选择性分别为45%和96%左右.TS-2催化剂的重复使用实验表明,TS-2催化剂在催化丙烯环氧化制环氧丙烷的反应中具有较好的催化活性和稳定性.     

Regeneration of Lamina TS-1 Catalyst in the Epoxidation of Propylene with Hydrogen Peroxide

The deactivation and regeneration of the lamina titanium silicalite (TS-1) catalyst for the epoxidation of propylene with dilute H₂O₂was investigated in a fixed-bed reactor. In the scale-up experiment, the dosage of the lamina TS-1 catalyst is 2. 5 kg, after 1000 h reaction the catalyst still exhibits good performance and further increases the reaction time, the conversion of H₂O₂begins to decrease. TG and BET analyses of the deactivated catalysts show that the main species occluded within the zeolite pore are propylene oxide oligomers, and these species occupying the active Ti site and blocking the pores of the lamina TS-1 are the main reason for the deactivation of catalyst. The deactivated catalyst can be regenerated by different regeneration methods. The activity of deactivated catalysts regenerated by dilute H₂O₂or heat treatment by using air or nitrogen as a calcination media can be fully recovered, but a decline in propylene oxide (PO) selectivity of the regenerated catalyst has been observed during the first hours of reaction. However, water vapor treatment of the deactivated catalyst can improve the PO selectivity with the same activity as that of the fresh lamina TS-1 catalyst.     

相转移催化H2O2环氧化环己烯合成环氧环己烷

对反应控制相转移催化剂制备方法进行了改进,催化剂产率可达94%,并用红外光谱(IR)和元素分析对催化剂进行了表征;将催化剂用于以w(H2O2)=34.5%为氧化剂,以质量分数76.7%的工业粗环己烯为原料合成环氧环己烷;探讨了反应时间、反应温度、环己烯与H2O2的摩尔比、催化剂用量、溶剂用量等因素对反应的影响。获得的较佳合成条件(以0.08 mol H2O2计)为:反应温度40℃,反应时间90 m in,催化剂用量0.6 g,n(C6H10)∶n(H2O2)=2.5∶1,溶剂1,2-二氯乙烷70 mL。该条件下环氧环己烷平均选择性为96.1%,环氧环己烷的平均收率达91.7%。将回收的催化剂用于反应,环氧环己烷的平均选择性和平均收率分别为95.3%和90.9%。     

丙烯环氧化中TS-1寿命

钛硅催化剂 (ＴＳ - 1)催化下的丙烯与Ｈ2 Ｏ2 环氧化过程是环氧丙烷 (ＰＯ)洁净生产的发展方向[1,2 ] ,反应条件温和 ,选择性高 ,但目前的研究主要在催化剂制备 .虽然部分学者[3] 对催化剂的寿命进行了报道 ,但仅限于 5～ 8次间歇反应的累计结果 .本文根据动力学研究的结果[4 ,5] ,采用连续淤浆反应器 ,在最佳反应和加速反应条件下 ,对催化剂的寿命进行研究 ,测定了该催化剂的单程寿命 ,并用ＸＰＳ(Ｘ射线光电子能谱 )分析了催化剂失活的原因 ,为丙烯环氧化工艺的进一步工业化提供指导和依据 .实验中钛硅分子筛 (ＴＳ - 1)按文献 [2 ]合成 …     

Influence of Pt–Pd/TS-1 Catalyst Preparation on Epoxidation of Olefins with Hydrogen Peroxide

The catalytic performance of the platinum–palladium/titanium silicalite, which was a common catalyst for the direct epoxidation of olefins with hydrogen and oxygen, was tested by epoxidation of allyl chloride with hydrogen peroxide. The epoxidation capacity of the TS-1catalyst was reduced after loading palladium and platinum on it. Ti leaching and crystallinity decrease were observed by XRD and FT-IR. The decomposition of hydrogen peroxide was accelerated by the supported Pd and Pt. These contributed to the loss of epoxidation capacity of TS-1. Ti leaching and crystallinity decrease were probably main causes. We propose that the Ti leaching had the most important influence on the loss of epoxidation capacity     

外环流气升式反应器中催化丙烯环氧化反应

本论文研究了外环流气升式反应器中TS-1催化丙烯环氧化反应,以单位催化剂空时收率为目标,进行了反应工艺条件的优化,考察了结构参数,上升管与下降管横截面积之比Ar Ad对反应的影响。     

TS-1催化H2O2与甲基氯丙烯环氧化

以TS-1为催化剂,以30％（质量分数）H2O2为氧化剂催化2-甲基-3-氯丙烯（MAC）环氧化,考察了溶剂种类与用量、反应温度、反应物摩尔配比及催化剂TS-1质量浓度等因素对环氧化反应的影响。结果表明,反应的最佳溶剂为甲醇;增加催化剂质量浓度和升高反应温度均有利于提高转化率和H2O2有效利用率,但同时降低了反应的选择性;从反应物摩尔配比兼顾反应的转化率和H2O2有效利用率两方面来考虑,本试验条件下选1：1为佳。     

Propylene Epoxidation Over Silver Supported on Titanium Silicalite Zeolite

Epoxidation of propylene to propylene oxide over Ag/TS-1 in the presence of oxygen and hydrogen was carried out in a fixed-bed, quartz flow reactor. The effects of Ag loading, Si/Ti ratio of TS-1 and calcination temperature and calcination method of Ag/TS-1 on the propylene epoxidation were investigated. The results show that Ag loading, the calcination temperature and calcination method of Ag/TS-1 as well as the Si/Ti ratio of TS-1 have a great effect on the catalytic properties. The optimum Ag loading, calcination temperature and calcination method of Ag/TS-1 and Si/Ti ratio of TS-1 are 2 wt%, 450 °C in air and 64 respectively. Over 2.0 wt% Ag/TS-1(n_Si/n_Ti = 64) catalyst, at a space velocity of 3000 h^-1, 0.92% propylene conversion with 91.21% selectivity to propylene oxide is obtained at 150 °C. The deactivation of Ag/TS-1 catalyst is not due to the changes of active species, but because of the coke of the catalyst, which can be easily regenerated by calcination at 450 °C in air.     

Epoxidation of Butadiene Over Nickel Modified TS-1 Catalyst

Abstract  

Nickel modified Titanium silicalite 1 (TS-1) catalysts provided an environmentally benign and effective method for butadiene epoxidation. Certain loading of modified Ni in our system significantly promoted TS-1 catalytic activity. The product vinyloxirane (VO) was obtained with high yield of 0.49 mol/L (theoretic equilibrium value 0.52 mol/L). The turnover number (TON, determined as the molar VO obtained per molar Ti atom) reached 1,140. Besides, the catalyst kept high activity during five runs of reusability test. XRD, N₂ adsorption and desorption, TPR, XPS, FT-IR and DR UV–Vis were employed to characterize the specific Ni role to Ti-site in Ni/TS-1 catalysts.     

国外用过氧化氢环氧化丙烯制环氧丙烷研发近况

介绍了国外用过氧化氢环氧化丙烯制备环氧丙烷（PO）工艺技术近期研发概况,内容包括所用过氧化氢来源（来自蒽醌法或氢、氧直接化合法）、丙烯环氧化反应以及反应产物精制和原料回收循环利用过程,工艺涉及催化剂、溶剂、流程、反应器、操作方法和试验结果等。不少工艺是将过氧化氢合成与丙烯环氧化加以耦合,形成完整体系,提高运转效率和经济效益。此外,简略介绍了用过氧化氢制PO工艺在产业化方面的最新进展。     

Direct Oxidation of Propylene to Propylene Oxide with Molecular Oxygen: A Review

The direct oxidation of propylene to propylene oxide (PO) using molecular oxygen has many advantages over existing chlorohydrin and hydroperoxide process, which produce side products and require complex purification schemes. Recent advances in liquid-phase and gas-phase catalytic oxidation of propylene in the presence of only molecular oxygen as oxidant and in absence of reducing agents are summarized. Liquid-phase PO processes involving soluble or insoluble Mo, W, or V catalysts have been reported which provide moderate conversions and selectivities, but these likely involve autoxidation by homogeneous chain reactions. Gas-phase PO catalysts have been mostly Ag-, Cu-, or TiO₂-based substances, although other compositions such as Au-, MoO₃-, Bi-based catalysts and photocatalysts have also been suggested as possibilities. The Ag catalysts differ from those used for ethylene oxide production in having high Ag contents and numerous additives. The additives are solid-phase alkali metals, alkaline earth metals, and halogens, with the most common substances being NaCl and CaCO₃. Nitrogen oxides in the form of gas-phase species or nitrates have also been found to be effective in enhancing PO production. Direct epoxidation by surface nitrates is a possibility. Titania catalysts supported on silicates have also been reported. These have higher PO selectivities at high conversion than silver catalysts.     

低成本TS-1的制备及其在丙烯环氧化中的应用

综述了低成本钛硅分子筛TS-1的制备及其在丙烯环氧化反应中的应用研究进展。低成本TS-1制备过程实现工业化主要存在粉末状TS-1的回收和过氧化氢的生产、储存等问题。提高活性及进一步降低成本是研究的重点。过氧化氢的生产与丙烯环氧化过程的集成是未来的发展方向。     

钛硅分子筛催化合成1,2-环氧丁烷

研究了以TS 1钛硅分子筛作催化剂 ,以 30 %H2 O2 为氧化剂 ,1 丁烯催化环氧化反应。使用均匀设计方法详细考察了H2 O2 用量、催化剂用量、反应温度、反应时间等因素对反应的影响。得到了H2 O2 的转化率和 1,2 环氧丁烷的选择性与以上因素的回归公式 ,并通过实验对其进行了验证。     

TS-1催化丙烯环氧化反应及动力学研究

研究了丙烯环氧化反应条件,系统考察了反应压力、溶剂中水质量分数、TS-1质量分数以及反应温度对过氧化氢转化率以及环氧丙烷选择性的影响,采用非机理速率方程确定了主反应动力学参数。并采用该反应动力学模型对TS-1质量分数、溶剂中水质量分数对在不同温度下的双氧水转化速率常数进行了关联。为今后建立复杂动力学模型以及该工艺的工业化打下了良好的基础。     

丙烯环氧化合成环氧丙烷新技术的研究进展

评述了以分子氧和双氧水为氧源的丙烯环氧化催化剂体系的最新研究进展。其中包括金属Ag催化剂。金属熔盐混合物，钛硅沸石TS-1和过渡金属络合物催化剂体系，根据氧转移机理。金属Ag催化剂和熔盐体系是以分子氧为直接氧源，而TS-1和最近报道的反应相转移含钨催化剂本质上是以过氧化氢为直接氧源。TS-1和反应相转移含钨催化剂和优点是反应条件较温和，生成环氧丙烷的选择性和产率较高。如一种负载成“蛋壳醇作为溶剂），环氧丙烷选择性和产率（以双氧水计）分别可达92%和90%以上。催化剂运转1000h以上性能稳定，今后的一个重要发展方向是开发以分子氧为起始氧源，简单高效的原位双氧水工艺。     

杂多化合物催化过氧化氢氧化烯烃环氧化反应研究进展

烯烃的环氧化反应是化学工业中重要的化学反应之一,其环氧化物是用途极为广泛的有机原料和化学中间体。文章综述了以杂多酸为催化剂,过氧化氢为氧化剂的烯烃环氧化反应研究进展,指出了今后此类环氧化反应催化剂发展方向。     

醇溶剂中TS-1催化丙烯环氧化的本征动力学与反应机理研究

研究了在三种不同醇溶剂(甲醇、异丙醇和仲丁醇)水溶液中TS—l催化丙烯过氧化氢环氧化反应的本征动力学，反应条件为温度30～60℃，丙烯压力0．4-0．6MPa。根据实验现象和各组分在TS-1上的吸附特点建立了该反应的Eley-Rideal机理模型，环氧化反应在吸附态的H2O2分子与游离态的丙烯分子之间进行，表面反应为速度控制步骤。通过实验数据对机理模型进行了参数估值，检验结果表明拟合效果较好，平均偏差在10％以内。最后对过程进行了进一步讨论，为该过程的工业化提供了依据。     

环氧丙烷生产工艺进展

综述了近年来环氧丙烷合成工艺的新进展,包括对现有环氧丙烷生产工艺的革新、直接氧化法、光催化环氧化等方法,并对各种方法的特点和发展前景进行了讨论.     

环辛烯双氧水相界催化环氧化反应研究

以氯甲基化大孔聚苯乙烯-二乙烯苯交联树脂接枝N-苄基-N,N-二甲基-N-十二烷基季铵磷钨杂多酸盐为相界催化剂,进行了无搅拌条件下的环辛烯双氧水催化环氧化反应研究。对影响反应的因素如催化剂用量、反应温度、双氧水与环辛烯摩尔比、双氧水质量分数、溶剂、催化剂颗粒直径、催化剂重复使用性等进行了讨论。结果表明,催化剂可以处于环辛烯双氧水界面处,在完全没有搅拌的条件下催化环辛烯的环氧化反应。在无溶剂、无搅拌、催化剂0.3g,n(双氧水):n(环辛烯)=1.5:1,反应温度72℃,静止反应8h的条件下,环氧环辛烷的产率可达99%以上。催化剂重复使用5次未见活性明显降低。     

金催化剂在丙烯气相直接环氧化反应中的应用

环氧丙烷（PO）是一种重要的有机化工原料。近来发现采用沉积-沉淀法将金高度分散在一些含钛物质表面上时,能够催化H2-O2-丙烯气相体系直接合成PO。金粒大小和分散状态,载体及助剂等因素对催化剂性能有重要影响。主要就催化剂性能的影响因素,反应及失活机理等方面的研究进展情况进行了总结和评述,以利于将来深入地研究。