改性Ti-MCM-41催化剂对过氧化氢异丙苯环氧化丙烯反应的影响

以NH_3氮化法和甲基硅烷化法等改性方法处理Ti-MCM-41分子筛,并研究了不同改性方法对分子筛结晶度、结构、酸性及疏水性的影响;考察了改性分子筛催化剂对不同来源过氧化氢异丙苯(CHP)催化环氧化丙烯制环氧丙烷(PO)反应的影响。采用XRD、N_2吸附-脱附、FTIR、Py-IR、UV-Vis等表征方法对催化剂结构进行表征。表征结果显示,改性处理会导致分子筛孔道收缩、结晶度降低,但仍具有MCM-41分子筛的六方相孔结构。实验结果表明,NH_3氮化改性的催化剂,由于酸强度降低,能减少CHP无效分解,CHP的利用率由66.1%提高至80.4%;而经甲基硅烷化改性的催化剂,由于表面疏水性的提高,可提高PO的选择性至99.6%。     

Thermolysis of 2-[4-(chloro-<Emphasis Type="Italic">tert</Emphasis>-butyl)phenyl]propan-2-yl hydroperoxide: Kinetics and mechanism

The kinetic features and products of the thermolysis of 2-[4-(chloro-tert-butyl)phenyl]propan-2-yl hydroperoxide in the temperature range 120–190°C have been studied. The mechanism of the process is discussed.     

Use of ionic liquids in cyclohexene epoxidation with hydrogen peroxide

A comparative study of the reaction of catalytic epoxidation of cyclohexene with hydrogen peroxide in water and ionic liquids containing dihydrogen phosphate anions, such as trimethylammonium dihydrogen phosphate, diethylammonium dihydrogen phosphate, and N-methylpyrrolidonium dihydrogen phosphate has been performed. It has been shown that as high a cyclohexane epoxide yield as 80% with a selectivity close to quantitative can be obtained under optimum conditions by controlling the ratio of the ionic liquid components.     

Effect of the solvent nature on the magnesium 2-ethylhexanoate-catalyzed decomposition of cumene hydroperoxide

Decomposition of cumene hydroperoxide (CHP) in benzene, chlorobenzene, and carbon tetra-chloride in the presence of magnesium 2-ethylhexanoate has been investigated. It has been determined and kinetically proved that the degradation is preceded by the formation of an intermediate hydroperoxide-catalyst complex; the thermodynamic parameters of the complex formation have been determined. It has been found that the catalytic activity of magnesium 2-ethylhexanoate in carbon tetrachloride is higher than in chlorobenzene and benzene. The stability of the complex depending on the nature of the solvent decreases in the order C₆H₅Cl > CCl₄ > C₆H₆.     

过氧化叔戊醇对柴油氧化脱硫的工艺优化

以过氧化叔戊醇（TAHP）为氧化剂、MoO3/D 113为催化剂、N-甲基吡咯烷酮（NMP）为萃取剂,对焦化柴油进行氧化-萃取脱硫实验,考察了氧化温度、氧化时间、氧化剂用量、催化剂用量、萃取剂用量等工艺条件对脱硫率的影响.结果表明,最适宜的氧化-萃取脱硫工艺条件如下:氧化温度90 ℃,氧化时间2.5h,氧化剂/柴油（摩尔比）4,催化剂用量0.1g,萃取剂/柴油（体积比）1;在此条件下,柴油中硫化物的脱除率为96.8％,含硫量降至29.7 μg/g,柴油的回收率达98.6％.     

钛硅分子筛催化氧化苯乙烯反应动力学研究

研究了以丙酮为溶剂、钛硅分子筛（TS-1）／H2O2体系催化氧化苯乙烯的宏观动力学。催化氧化反应条件为：反应温度50-80℃、催化剂用量（以10mmol苯乙烯计）0．4g、n（苯乙烯）：n（H202）=1：1、n（丙酮）：n（苯乙烯）=12：1。得出TS-1／H2O2体系催化氧化苯乙烯的反应为一级反应,反应活化能为17．35kJ／mol,苯乙烯反应动力学方程为：rA=5.0234e-17.35×10^3/KTCA.     

2-丁炔1,4-二醇合成动力学

采用P-B实验设计方法,从炔醛法合成丁炔二醇的诸因素中筛选出了关键变量,建立了多元一次线性方程及机理型动力学方程,求得了各动力学参数与温度变化的关系式,可作为选择最佳操作条件和反应器放大设计的依据。     

Photocatalytic Oxidation Kinetics of Thiophene with Nano-F-/Fe3+/TiO2

Photocatalytic oxidation kinetics of thiophene in n-octane/water extraction system was studied with fluorine and ferric ion codoped nano-TiO2(nano-F/Fe3+/TiO2)powders used as the photocatalyst.Effects of initial concentration of thiophene and additional dosage of F-/Fe3+/TiO2 on the reaction rate constant and half-life were investigated.The results showed that the appropriately added dosage of F-/Fe3+/TiO2 was 0.1 g in the 100-mL reaction system and the photooxidative kinetics of thiophene in the presence of F-/Fe3+/TiO2 catalyst was of first-order with a rate constant of 0.6508 h-1 and a half-life of 1.0651 h.The desulfurization rate of thiophene was 98.1% in 5 h and the sulfur content could be reduced from 800 ppm to 15 ppm The reaction rate constant increased with a decreasing initial concentration of thiophene.     

离子液体在烯烃环氧化反应中的应用

研究了1-辛烯、环辛烯等多种烯烃的环氧化反应,考察了反应温度、反应时间、催化体系循环使用次数等因素对环氧化反应的影响。结果表明,在离子液体1-甲基-3-丙酸咪唑硫酸氢盐中,以H2O2质量分数为30%的双氧水溶液为氧化剂,以[[(phens)2(H2O)FeⅢ]2(μ-O)](ClO4)4为催化剂,在反应温度为5℃,反应时间为15 min的最佳工艺条件下,1-辛烯转化率可达99%;催化活性随催化体系循环使用次数的增加而逐渐下降。     

铬-磷催化剂烧炭动力学

在常压(?)400—550℃的条件下,分别以不同粒度(20—40,40—60,60—80目)的催化剂,在流化床积分反应器中,获得了铬-磷催化剂烧炭动力学速度方程式v=k_0exp(-E/RT)·P_(o2)·C_c。其中活化能E=95.29-kJ/mol,k_0=3.25×10~5S~(-1)·atm~(-1)。首先进行了催化剂颗粒和流速对扩散的影响试验,发现表面反应为速率的控制步骤。实验结果表明,480℃以上与连续模型相符,低于480℃时与缩核摸型相符。     

Decomposition of cumene hydroperoxide over molybdenum oxo-peroxo compounds

The features of the catalytic decomposition of cumene hydroperoxide (CHP) were studied by the pulse technique in an inert gas atmosphere over the temperature range 90–120°C and the concentration range 0.1–2.5 mol/l. As a catalyst, molybdenum(VI) oxo-peroxo compounds active in the olefin oxidation reaction were used, which were prepared from cumene hydroperoxide and hydrogen peroxide. The rate and activation parameters for the formation and degradation of the CHP-catalyst complex were determined, as well as the thermodynamic characteristics of complexation.     

Formation of active sites in titanium-containing zeolites with MFI structure in propylene epoxidation with hydrogen peroxide

Propylene epoxidation with hydrogen peroxide on titanosilicates with different Si/Ti ratios and various states of titanium in the catalysts, prepared by hydrothermal crystallization according to two different procedures, has been investigated. It has been demonstrated that a change in the pH of the crystallizing gel leads to a change in the sequence of titanium insertion in the zeolite structure at a hydrothermal synthesis temperature of 170°C. It was shown that titanium incorporated in the zeolite framework in the tetrahedral positions is an active site in the epoxidation reaction, whereas titanium in the form of titanium dioxide leads to unproductive degradation of hydrogen peroxide.     

MoP/SiO2-TiO2-ZrO2催化喹啉加氢脱氮的反应动力学

 采用共沉淀法和共浸渍法制备了MoP/SiO₂-TiO₂-ZrO₂催化剂。以喹啉为模型化合物,在固定床微反应器中考察了MoP/SiO₂-TiO₂-ZrO₂催化剂的加氢脱氮（HDN）活性;在氢分压2~5 MPa、反应温度300~400℃、氢/油体积比200~800和体积空速2~8 h^-1条件下,建立了其HDN的反应动力学模型。结果表明,MoP/SiO₂-TiO₂-ZrO₂催化喹啉HDN反应中,脱氮率随着反应温度升高先增加后趋于平缓,喹啉转化率则随着反应温度升高略有降低;脱氮率及转化率均随着氢分压增加而增加,随着体积空速增加而降低,而随着氢/油体积比增加变化不大。喹啉HDN的反应动力学模型为带有氮化物吸附的拟一级反应动力学模型,并结合Levenberg-Marquardt(L-M)算法对模型参数进行优化求解。将喹啉HDN反应的脱氮率实验值与模型计算值进行了比较,两者吻合较好,平均相对误差为6.87%。     

CO_2加氢合成二甲醚的动力学规律

采用固定床积分反应器和自制的Cu ZnO Al2 O3 /HZSM 5双功能催化剂 ,在排除催化剂内、外扩散阻力前提下研究了CO2 加氢合成二甲醚的本征动力学规律 ,考察了在不同停留时间、H2 /CO2 比、反应温度和压力等条件下产物气中CO2 、CO、甲醇和二甲醚浓度的变化规律 ,为建立CO2 加氢合成二甲醚本征动力学方程提供了动力学数据     

Kinetics Study of CO2 Absorption into Solutions of UDS

Abstract

CO₂ absorption kinetics in united-developed desulfur solvent (UDS; a multicomponent solvent) and methyldiethanolamine solutions are measured in a disk column under the temperature range from 303 to 323 K and solution concentrations range from 0.35 to 4.371 mol·L ^?1. Under the condition of UDS concentration of 50% (4.371 mol·L ^?1) and temperature of 313 K, N and k_obs are 5.561 × 10^?6 kmol·m ^?2·sec ^?1 and 4,183.372 sec^?1 , respectively. The absorption activation energy of CO₂ into UDS is 44.92 kJ·mol ^?1.     

Cumene hydroperoxide decomposition in the presence of organic zinc salts

Cumene hydroperoxide degradation in chlorobenzene in the presence of zinc naphthenate was studied. It was found and kinetically corroborated that the degradation is preceded by the formation of an intermediate complex of the hydroperoxide with the catalyst monomeric form. The kinetic and thermodynamic parameters of the complex are close to those recently found for zinc 2-ethylhexanoate. A procedure for the calculation of the concentration of the catalyst monomeric form from kinetic data is proposed.     

DQC催化剂的丙烯本体聚合动力学研究

利用自建的动力学评价装置,采用单体补充法对DQC催化剂的本体聚合动力学进行了研究,考察了聚合温度、外给电子体种类及加氢量对催化剂聚合动力学的影响。实验结果表明,在60~70℃时,聚合温度的升高有利于提高反应速率;在70~80℃时,聚合温度对反应速率的影响不明显。外给电子体对DQC催化剂聚合动力学的影响差别不大,但二异丁基二甲氧基硅烷和环己基甲基二甲氧基硅烷在聚合初始阶段对DQC催化剂的激活作用更大。使用二异丙基二甲氧基硅烷时,DQC催化剂的聚合活性较高。DQC催化剂的聚合活性随加氢量的增大呈先增大后减小的趋势,当加氢量为77.2 mg时,聚合活性最高。     

Ni-Mo/TiO_2-Al_2O_3催化剂上柴油加氢脱硫反应动力学

采用高压滴流床反应器,在反应温度280～360℃、H2分压5～7 MPa、氢与油体积比300～900、液态空速1～6 h-1的条件下,考察了柴油在Ni-Mo/TiO2-Al2O3催化剂上的加氢脱硫反应规律,并建立了柴油加氢脱硫反应动力学模型。采用Levenberg-Marquard优化方法对实验数据进行回归,确定了反应动力学模型中的有关参数。实验结果表明,Ni-Mo/TiO2-Al2O3催化剂上柴油加氢脱硫反应为1.5级,表观活化能为78 002 J/mol。模型计算结果与实验数据吻合良好,平均相对偏差仅为2.7%。