甲苯与叔丁醇在超稳Y沸石上的烷基化反应研究

考察了HM、USY、Hβ、HZSM-5等4种沸石分子筛在甲苯与叔丁醇烷基化反应中的催化性能,用NH3-TPD和Py-IR等手段对几种催化剂的物化性质进行了表征.结果表明,除催化剂的酸量外,催化剂的酸种类和孔结构也是影响催化性能的重要因素;L酸在甲苯的叔丁基化反应中起主要活性中心作用,且强酸中心的存在对烷基化产物的选择性不利.采用催化活性较高的超稳Y沸石分子筛作催化剂,考察了反应条件对烷基化反应的影响.在适宜的操作条件下,即催化剂焙烧温度623 K、反应温度180℃、反应时间4 h、初始压力0.6 MPa和n(叔丁醇)/n(甲苯)为2时,甲苯转化率达46.4%,叔丁基甲苯(TBT)选择性为97.0%,对叔丁基甲苯(p-TBT)选择性为65.9%.     

四氢萘在含USY分子筛Mo－Ni加氢裂化催化剂上反应的研究

在国产３８２５型加氢裂化催化剂上，利用连续流动固定床微型反应装置，在４．５～８．５ＭＰａ和３２０～３８０℃条件下，测定了四氢萘加氢反应动力学数据，建立了四氢萘加氢裂化的反应网络和动力学模型。     

天然沸石活化处理研究

讨论了天然沸石用于除氟的可行性,通过静态实验优选出一种最佳的活化处理工艺,确定了最佳参数,对各种影响因素进行了研究。用实地含氟水样检验沸石除氟的可靠性。     

C—N键催化氢解反应研究进展

叙述了非杂环类含氮化合物和杂环类含氮化合物C—N氢解反应常用催化剂,讨论了苄基型含氮化合物的底物结构、催化剂及反应条件对C—N氢解反应的影响,初步探讨了C—N键催化氢解反应机理。认为C—N键的催化氢解反应不仅与含氮化合物的分子结构有关,还与催化剂的性能有关,若要从根本上提高C—N键氢解活性还需深入对反应机理的研究。     

介孔USY沸石负载Pd催化剂对大分子芘的深度加氢性能研究

通过水蒸气脱铝的方法制备含有介孔结构的超稳Y沸石(USYM),同时采用四氯化硅蒸汽脱铝方法制备了缺乏介孔的超稳Y沸石(USYSI).采用等体积浸渍方法将金属Pd负载到载体USYM,USYSI和Al-MCM-41 上用于大分子芘的加氢反应.芘加氢反应活性在USYM负载的Pd催化剂上明显高于USYSI和Al-MCM-41负载的Pd催化剂.催化剂的表征结果表明,与 USYSI相比,引入到USYM沸石中的介孔结构有利于大分子芘的扩散;Al-MCM-41相比,USYM沸石具有强酸中心有利于负载Pd催化剂对芳烃分子加氢活性的提高.     

气相色谱法分析甘油氢解制备丙二醇反应液组成

建立甘油催化氢解制备丙二醇产物的气相色谱定性定量分析方法.该分析方法能够准确地定量分析氢解产物乙醇,1,2-丙二醇,1,3-丙二醇,乙二醇和未反应的甘油,相对标准偏差为1.14％～2.65％,平均回收率在93.05％～103.91％之间,方程的线性相关性良好,是一种简单迅速、准确的分析方法.同时,通过分析数据能够计算反...     

预活化对PS微球化学镀镍的影响

研究了表面化学镀前处理工艺中活化条件(如活化时间、活化温度、活化pH值)对PS微球镀镍层的致密性、均匀性、导电性的影响,对活化后的PS微球进行了SEM和导电性测试。结果表明,在氯化钯用量为0.05g、活化时间为80~120min、活化温度为34℃、活化pH值为3~4的条件下,PS微球具有良好的镀层致密性及优良的导电性。     

Modified Beta Zeolite as Catalyst for Fries Rearrangement Reaction

Modified beta zeolites were applied as catalysts for the Fries rearrangement reaction. The properties of the modified zeolites were characterized by NH₃-TPD, n-hexane and 1,2,4-trimethylbenzene adsorption. Modification with SiO₂ did not block the pores of the beta zeolite but reduced the number of acid sites on the surface. However, when the beta zeolite was modified with Ce₂O₃, the number of acid sites determined by NH₃-TPD increased, which indicated that new acid sites are created by the interaction of cerium oxide and zeolite. Modified beta zeolites and H-beta were applied as catalysts for the Fries rearrangement of phenol acetate. Reaction over H-beta has low selectivity and the catalyst is easily deactivated. SiO₂ modification of the catalyst increases the selectivity of the reaction but decreases the conversion. Ce₂O₃-modified beta zeolites show higher catalytic activity and rearrangement selectivity in the reaction than other catalysts. The stability of the catalyst is also improved after Ce₂O₃ modification. About 70% selectivity and 60-80% conversion can be achieved over 16 wt% Ce₂O₃-modified beta zeolite.     

活化工艺对化学镀镍的影响

研究了一种以塑料为基材进行导电化处理的高稳定性离子钯活化工艺,并将其与胶体钯活化工艺进行比较。结果表明:与胶体钯活化工艺相比,离子钯活化工艺能有效提高化学镀镍层的形貌质量、硬度及光泽度。     

玻璃表面无钯活化化学镀镍的研究

利用热还原方法制备活性镍,取代了玻璃表面化学镀镍用钯活化的方法;探索了活化液的组成和制取活性镍的工艺条件,同时获得了在玻璃表面进行化学镀镍的镀液配方;通过ＳＥＭ对镀层的形貌和组成进行了观测。实验结果表明：所得镀液稳定、镀速好,镀制的镍层均匀、光亮;这说明玻璃表面用镍活化以取代用钯活化是一种可行的方法。     

天然沸石活化及除氟性能

为了提高天然沸石的除氟能力,采用了高温焙烧、酸碱处理和硫酸镁浸泡等方法活化天然沸石,研究其除氟性能.结果表明,各种方法均可在一定程度上提高沸石的吸附能力,其中以经过高温焙烧、硫酸浸泡、硫酸镁改性途径活化得到的沸石除氟效果最佳,改性后的沸石除氟容量是未改性的3.97倍,初步显示出该沸石良好的应用前景.     

镍活化双层镀镍屏蔽材料的设计

以聚酯纤维布为原料,用镍盐替代高昂的钯盐作为活化剂,采用微波法制备不同阻抗的镀镍导电纤维布;以平行铺层法制备成多层结构吸波材料。通过控制镀膜厚度,并优化铺层方案,达到较好的电磁屏蔽效果。     

Structural Effects of HZSM-5 Zeolite on Methanol-to-Propylene Reaction

ZSM-5 zeolite was synthesized using n-butylamine as a template under hydrothermal conditions. The morphology of the prepared zeolites was changed with the initial gel composition. The influences of OH⁻/template and H₂O/template ratios on the morphology, mesoporosity, acid properties, and crystal size of the synthesized zeolites were evaluated, also the structural effects of the prepared zeolites on the catalytic performances of the methanol-to-propylene process. Increasing the external surface area and mesopore volume of the catalysts improved the propylene selectivity. A direct relationship between the deactivation of catalysts and their acidic properties was found. The results were derived from laboratory data and need to be re-examined on a larger scale to ensure their accuracy on an industrial scale.     

Removal of Lead and Nickel Ions Using Zeolite Tuff

The capacity of Jordanian zeolite tuff for the removal of lead and nickel ions from aqueous solutions has been investigated under different conditions, namely zeolite particle size, initial solution pH, initial metal ion concentration, slurry concentration and solution temperature. Equilibrium data obtained have been found to fit both the Langmuir and Freundlich adsorption isotherms. It has been found that this zeolite (phillipsite) tuff is an efficient ion exchanger for removing both lead and nickel ions. Its removal capability is considerably higher for lead ions than for nickel ions under all conditions tested; however, the actual exchange capacities are far below the theoretical values. The finer the zeolite particles used, the higher the metal exchange capacity. An initial solution pH of 4·0 is favourable for obtaining high metal removal. © 1997 SCI.     

硫酸钯活化印制电路铜箔化学镀镍

文章介绍了以硫酸/硫酸钯作为印制电路铜箔化学镀镍的活化液。考察了表面活性剂的用量、活化时间及活化温度对化学镀镍的影响,确定了最佳的工艺参数。并对经该活化液活化的铜箔进行化学镀镍,通过扫描电镜(SEM)对化学镀镍层的微观形貌进行表征,同时考察了该镍层的钎焊性。研究结果表明,该活化液适用于印制电路铜箔的化学镀镍前活化。     

Influence of Reaction Parameters on the Hydrogenolysis of Hydroxymatairesinol Over Carbon Nanofibre Supported Palladium Catalysts

The density functional theory (DFT/B3LYP) calculations were applied to investigate the interaction of a Pt₆ particle with the ZSM-5 zeolite framework. The electronic structure of the metal particle is strongly affected by the interaction with basic framework oxygens and acid sites of the zeolite support. Adsorption on basic sites (E_ads = 6 kcal/mol) favors the formation of the electron enriched metal cluster. Interaction of the platinum cluster with the acid site characterized by stabilization energy of 47 kcal/mol results in oxidation of the metal particle and suppression of Brønsted acidity of the support. The hypothesis is put forward that the oxidized platinum particle can function as an active site for the alkane isomerisation on platinum supported high silica zeolites.     

Hydroisomerization of n-Heptane Over Cr Promoted Pt-bearing H3PW12O40 Catalysts Supported on Dealuminated USY Zeolite

The Pt-bearing H₃PW₁₂O₄₀ (PW) catalysts, promoted by Cr or La, supported on dealuminated USY zeolite were prepared and their catalytic activities were evaluated in the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor. The catalysts were characterized by XRD, BET, IR and H₂-chemisorption. The results showed that the dealuminated USY support retained the Y zeolite structure and the PW well kept its Keggin structure in the supported PW catalysts and the doping of Cr or La into the catalysts enhanced the dispersion of Pt on the catalyst surface. The Pt-bearing PW catalysts doped with Cr or La, especially Cr, exhibited much higher catalytic activity and selectivity than the catalysts without dopants. Both the conversion and selectivity were discussed in relation with physicochemical properties of catalysts.     

镍系顺丁橡胶聚合反应控制探讨

本文主要结合茂名石化新开顺丁橡胶装置,通过顺丁橡胶聚合单元开车初期的调试,利用理论结合实践,总结聚合系统各组分催化剂之间的配方与通过不断调整各组分催化剂的配比积累的经验方法,探讨影响聚合反应的条件,优化控制项目,可更好地生产出优质门尼的顺丁橡胶,提高产品质量,使整个顺丁橡胶装置产生最佳的经济效益。     

Trifunctional Squaramide Catalyst for Efficient Enantioselective Henry Reaction Activation

A new class of trifunctional squaramide catalyst acting by means of multiple interactions has been found in a study of the Henry reaction. Enantiomerically enriched nitroaldol products were obtained in good yields and high enantioselectivities under mild conditions using one of the smallest amounts of organocatalyst reported so far for this reaction (0.25 mol%). The catalyst was able to generate hydrogen bonding and anion‐π/hydrogen‐π interactions with the substrates, responsible of the improvement in the reactivity and the enantioselectivity of this process. Computational calculations support a mechanistic hypothesis based on an anion‐π effect, this being the first example reported in asymmetric catalysis.

     

Hydrogenolysis of glycerol with FeCo macrocyclic complex bonded to Raney Nickel support under mild reaction conditions

The hydrogenolysis of dilute glycerol solution to 1,2‐propanediol was studied in the presence of heterogeneous catalyst (FeCoL/Raney Nickel) having a heterodinuclear FeCo macrocyclic complex ionically bonded to Raney Nickel. Studies on the stability of the complex bonded to the support were carried out at different temperature as well as the effect of solvent to confirm that it was stable up to 600°C and 100 h of refluxing. In the hydrogenolysis of glycerol, the temperature has been varied from 165 to 220°C with an initial hydrogen pressure 0.35 MPa and the conversion increases from 1% to 36% with no gases evolving in this temperature range. The major product is 1,2‐propanediol which is formed with 80% selectivity. The initial water content (20–60%) in the feed was also varied and it was found that the conversion and yield of 1,2‐propanediol increases when the water content increases. Based on literature, a kinetic model was proposed and optimal rate constants determined using Genetic Algorithm (GA).