双氧水生产用钯催化剂的再生复活研究

介绍了双氧水的性质、用途及应用前景;通过小试,对某双氧水生产装置失活钯催化剂进行了再生试验研究。     

浅析双氧水生产用钯催化剂的合理使用

阐述就目前国内采用蒽醌法固定床钯催化剂生产双氧水的使用现状、存在问题及如何正确使用。     

蒽醌法双氧水生产中钯催化剂的使用

介绍了蒽醌法双氧水生产工艺,着重对催化剂的装填、活化、维护、再生过程进行了阐述.提出了优化催化剂使用的措施.     

葸醌法双氧水生产中钯催化剂的使用

介绍了蒽醌法双氧水生产工艺，着重对催化剂的装填、活化、维护、再生过程进行了阐述。提出了优化催化剂使用的措施。     

蒽醌法钯催化剂工艺双氧水生产技术要点

从生产实践的角度分析了蒽醌法钯催化剂工艺双氧水生产过程中应注意的一些技术问题和安全事项,并提出了一些建议和措施。     

新型钯催化剂成功用于双氧水生产

<正>山东百川汇通化工科技有限公司研制生产的AHC-GII型钯催化剂,日前在山东海力化工股份有限公司15万吨/年双氧水装置上成功应用,一次开车成功。     

新型钯催化剂成功用于双氧水生产

<正>山东百川汇通化工科技有限公司研制生产的AHC-GII型钯催化剂,近期在山东海力化工股份有限公司15万t/a双氧水装置上成功应用,一次开车成功。AHC-GII型钯催化剂由先进的非均布负载技术制备而成。经中科院大连化学物理研究所分析检测、中石化股份     

钯催化剂双氧水装置生产初期控制要点分析

以台湾南亚公司双氧水装置为例，介绍了钯催化剂固定床生产初期所遇到的一些常见问题及控制手段。即，在开车初期应通过使用氮气来控制氢化塔的压力，氢气的安全量可控制为工作液流量的5倍，氢化塔温度波动范围控制不超过1℃，加强对工作液组分的控制，保证系统的稳定性。     

蒽醌法双氧水生产中钯催化剂的使用与维护

介绍催化剂的结构组成与加氢催化原理,结合生产实践,指出影响钯催化剂活性的因素,比较了几种再生方法的优劣。     

双氧水生产中钯催化剂的使用若干问题的探讨

阐述了双氧水生产中钯催化剂使用中存在的几个重要问题,并提出改进措施.对双氧水生产中钯催化剂使用温度进行了探讨.通过建立氢化反应温度和氧化铝再生温度之间的关联和良性互动,即氧化铝再生温度随着氢化温度的升高而升高,从而提高氧化铝对降解物的再生效果,可以使钯催化剂运行温度较过去提高10 ℃以上.通过观察分析发现,停车前停氢不补氮气运行,导致固定床底压比顶压高出很多,底部封存的气体快速上升,冲击上层瓷球,是引起催化剂床瓷球下翻的重要原因,并提出改进措施.提出新催化剂和再生后的催化剂使用前不活化更好,再生的水流量对再生效果有较大影响,最好要达到工作液流量的20%～30%,才能有效清除污物.     

蒽醌加氢钯催化剂载体改性研究

针对Pd/Al2O3催化剂载体的改性进行研究,将1 000℃焙烧后的氧化铝粉末与未焙烧的活性氧化铝粉末按不同比例混合和焙烧制备载体,采用等体积浸渍法制得负载Pd的Pd/Al2O3催化剂。采用XRD、BET、NH3-TPD和HOT对载体以及催化剂进行表征,并考察催化剂的蒽醌加氢性能。结果表明,提高载体中焙烧后氧化铝粉末的比例,导致载体中γ-Al2O3减少和δ-Al2O3增多,载体酸性降低,Pd分散度变大,从而提高了催化剂氢化效率。当焙烧后氧化铝质量分数为40%时,分散度和活性表面积达到最大,晶粒度最小,氢化效率最高,催化活性最佳。     

Preparation of Pd/Al2O3/Al catalysts for CO removal

Aluminum was carefully anodized, then palladium salts were supported on its A1₂O₃ surface layer by ion-exchange. CO 3.76 vol% contained in the air can be eliminated at around 200 °C. Both anodization conditions and the nature of the precursor solutions affect catalyst nature, particularly the pH value of the precursor solutions. The pH value of the solution suitable for supporting active components is 5–6. Palladium, which is present as Pd²⁺ and Pd⁴⁺ after calcination,distributes uniformly on the support surface which had a honeycomb structure.     

甲醇合成催化剂使用效果的影响因素及对策

介绍了甲醇合成催化剂的制造及使用过程,探讨了催化剂的失活方式及其机理,提出防止或消除这些因素、延长甲醇合成催化剂寿命的方法。     

The effect of ionic liquids on product yield and catalyst stability

The effect of ionic liquids on product yield and catalyst stability has been investigated through Suzuki cross-coupling of phenylboronic acid and 4-bromoacetophenone in organic solvents, ionic liquids and mixtures of organic solvents and ionic liquids.     

A comparison of ethanol and water as the liquid phase in the direct formation of H2O2 from H2 and O2 over a palladium catalyst

Ethanol and water have been compared as the media in which hydrogen peroxide is produced from the reaction of H₂ and O₂ over a palladium catalyst. There are significant differences between the reaction in the two media with respect to the net rate of H₂O₂ formation, the state of the active Pd and the mechanism of the reaction. The reactions were carried out at atmospheric pressure and at 10 °C, with O₂ and H₂ being introduced in a 4/1 ratio through a glass frit. In ethanol, using 50 mg of 5 wt % Pd/SiO₂, 1.8 wt% H₂O₂ was attained in 7 h; whereas, about half this amount was attained in water. In addition, the net formation rate did not remain constant in water. Both systems were 0.17 N in HCl, which facilitated the formation of colloidal Pd in water but not in ethanol. The loss of activity in water is attributed to the instability of the colloid, which has been shown previously to be the active state of Pd. By contrast, these results show that supported Pd is the active state of the metal in the ethanol system. The mechanism for the formation of the nonselective product, water, also is affected by the media in which the reaction is carried out. In ethanol, water is formed by the direct reaction of H₂ and O₂, while in the aqueous phase, water appears to be formed both by the direct pathway and by the reduction of H₂O₂.     

Isotope effect of H2/D2 and H2O/D2O for the PROX reaction of CO on the FeOx/Pt/TiO2 catalyst

The oxidation reaction of CO with O₂ on the FeOx/Pt/TiO₂ catalyst is markedly enhanced by H₂ and/or H₂O, but no such enhancement occurs on the Pt/TiO₂ catalyst. Isotope effects were studied by H₂/D₂ and H₂O/D₂O on the FeOx/Pt/TiO₂ catalyst, and almost the same magnitude of isotope effect of ca. 1.4 was observed for the enhancement of the CO conversion by H₂/D₂ as well as by H₂O/D₂O at 60 °C. This result suggests that the oxidation of CO with O₂ via such intermediates as formate or bicarbonate in the presence of H₂O, in which H₂O or D₂O acts as a molecular catalyst to promote the oxidation of CO as described below.      

预还原型氨合成催化剂还原度的分析

对预还原型氨合成催化剂还原度的分析,目前暂无相对准确的方法。介绍了用滴定法测定预还原型氨合成催化剂中的金属铁和总铁的质量分数,二者之比即为预还原型氨合成催化剂的还原度。     

纳米固体超强酸SO2-4/SnO2-La2O3-SiO2制备及催化反应研究

制备纳米SO4^2-／SnO2-La2O3-SiO2固体超强酸催化剂,讨论了在纳米载体SiO2的存在下,Sn、Si摩尔比、焙烧温度对乙酸转化率的影响,并与SO4^2-／SnO2-SiO2催化剂进行了对比,讨论了金属La^3 对固体超强酸的影响。实验表明,SO4^2-／SnO2-La2O3-SiO2催化剂在焙烧温度为450℃,n(Sn)：n(Si)=0．5时,乙酸的转化率达到98．1％。     

Pt／Al2O3气相苯加氢催化剂的研制

对气相苯加氢制环己烷的Pt／Al2O3苯加氢催化剂进行了研究,考察了催化剂的制备方法、Al2O3载体的物性及竞争吸附剂的种类等对催化剂性能的影响,按优化条件制备了Pt／Al2O3苯加氢催化剂。参考工厂苯加氢制环己烷工艺条件,采用加压原粒度活性评价装置,测试了该催化剂的活性和选择性。评价结果表明,该催化剂的主要性能达到了国外同类型催化剂的水平。     

碳载体催化剂中铂-钯的分离与定量分析

采用高温灰化法除碳 ,用氯仿对铂 -钯进行分离 ,然后用分光光度法和电位滴定法分别测定铂和钯。对方法的可靠性进行了验证 ,对关键性问题进行了讨论。结果表明该方法合理可行 ,测定结果准确可靠