Developments in catalysts of ethylbenzene dehydrogenation

通过对乙苯脱氢制苯乙烯工业催化剂演变过程的分析，认为近年催化剂组成已经历由fE-k-Cr系列向fE-k-CE系列以及由高钾含量向低钾含量的过渡。催化剂制备工艺也有诸多改进，颗粒形状由传统圆柱形向齿轮柱形及三叶柱形等异型颗粒演变。关于催化活性本质的研究渐趋活跃，多数研究者认为活性相是k2fE2O4，钾流失是催化剂在正常操作条件下逐渐老化的根本原因。ccording to the evolution of the commercial catalysts for dehydrogenation of ethylbenzene to styrene,it was deduced that the basic composition of these catalysts was transformed from Fe-K-Cr to Fe-K-Ce system and the potassium content in the catalysts was greatly decreased since the end of 1980′s.The production technics of the catalysts also had some improvements and the ethylbenzene dehydrogenation catalysts with ribbed or trilobate shapes appeared in the market recently.Studies focusing on the nature of the active phase of these catalysts and on the mechanism of catalyst aging were taken more and more attentions.It was concluded by most of the researchers that K_2Fe_2O_4 was the active phase of the catalysts and potassium migration from the catalysts was the main reason of the catalyst aging

Development of Catalysts for Ethylbenzene Dehydrogenation

XH系列催化剂主要用于乙苯脱氢制苯乙烯。该系列催化剂用氧化铁为主要活性组份，以钾和铈为主要助催化剂，并含有其它添加剂，至今已有五种牌号相继投放市场。针对XH系列催化剂开展了基础性研究，探讨催化剂的活性相、助剂的作用及晶格氧参与脱氢反应的机理。he　XHseries　catalysts　are　mainly　used　for　the　dehydrogenation　of　ethylbenzene　to　styreneUp　to　now,there　are　five　industrial　catalysts　named　after　XHThe　main　active　component　of　the　XHseries　catalysts　is　iron　oxide,and　potassium　and　cerium　oxides　are　the　main　promotorsIt　can　be　shown　by　investigating　the　interaction　between　potassium　promotor　and　iron　oxide,and　the　relationship　between　catalytic　activity　and　potassium　amount　carried　on　the　surface　of　a　model　catalyst,that　KFeO2　might　be　the　active　phase　of　these　catalystsThe　nature　of　Ce　promotion　is　suggested　as　a　donor　of　lattice　oxygen　to　the　KFeO2　active　phas

The Role of Lattice Oxygen and Potassium in Iron-Oxide-Based Catalyst For Dehydrogenation of Ethylbenzene

采用程序升温还原反应（TPr）、XPS、高温真空Xrd及活性和比表面测定等方法对单组分fE_2O_3、双组分fE_2O_3-k_2O催化剂及工业用XH-03催化剂研究晶格氧的性质和钾的助催作用；结果表明，纯fE_2O_3催化剂表面氧种的还原程度差别较大，反应时晶格氧易于失去，造成缺氧而迅速失活，钾的加入使催化剂生成新的k_2f_E2O_4相，其表面氧种的还原性趋向一定的温度范围，晶格氧数量增加，且其稳定性也增加，从而同时促进了氧转移脱氢和直接脱氢反应的活性，因此认为k_2fE_2O_4可能是活性相，脱氢反应的活性中心应由fE--（2＋）、fE--（3＋）、还原程度一定的晶格氧和k--＋组成。The role of lattice oxygen and potassium in iron-oxide-based catalysts (Fe_2O_3, Fe_2O)3-K)2O and commercial XH-0 3 ) has been investigated by using TPR(temperature programmed reduction), XPS, high temperature XRD and determination of activity and speciFic surFace area, The high temperature XRD study of the K-promoted iron-oxide catalyst has been shown to have the Formation of new crystalline phase of K_2Fe_2O_4, which promoted the reaction activity. The reduction levels of lattice oxygen are considerably diFFerent at the surFace of Fe_2O_3 catalyst beFore and aFter the reaction.The lattice oxygen was Found to lose easily and resulted in deFiciency of oxygen, which brought about the deactivation of the catalyst on the unpromoted Fe_2O_3 catalyst.At the surFace of K-promoted catalyst, it has an increase in quantity and stability of lattice oxygen and , consequently , increases the activity of the direct heterolytic dehydrogenation and oxygen-transFer dehydrogenation of ethylbenzene.The role of K is to stabilize the interconversion between Fe￣(2+) and Fe￣(3+) and to improve the electron transport between the neighboring active-sites, subseqently promoted the dehydrogenation and the selFregeneration.In this paper, the active phase of the catalyst is suggested to be K_2Fe2O_4 and the active center ofdehydrogenation to be consisted of Fe￣(2+), Fe￣(3+), lattice oxygen at certain reduction level and K￣+

Mossbauer Spectroscopic Characterization on Promotion of CaO in Catalysts of Ethylbenzene Dehydrogenation

穆斯堡尔谱学研究表明，在k2O-fE2O3体系中引入CAO促进k2O与fE2O3之间的相互作用，降低k1＋XfE11O17的生成温度.而且，CAO的引入还降低了在k2O-fE2O3体系中产生“α-fEOOH“物种所必须的k2O含量（由约17%降低为约8%）.在乙苯脱氢反应条件下所发生的fE3＋被还原为fE2＋的过程，亦被钙的存在所延缓.The Promotions of CaO in the catalysts of ethylbenzene dehydrogenation to styrene were investigated by M6ssbauer studies, which showed that the interaction between K2O and Fe2O3 was enhanced and the formation temperature of K1+xFe11O17 was depressed by the introduction of CaO into K2O-Fe2O3 system.Moreover, the necessary content of K2O in K2O-Fe2O3 system for the formation of "a-FeOOH" species was reduced from about 17% to 8% by the introduction of CaO.We also found that the process of reduction from Fe3+ to Fe2+ in the Fe2O3 based catalysts under the condition of ethylbenzene dehydrogenation was retarded by the presence of Ca in the catalysts.中国石油化工集团公司资

Mssbauer Spectroscopic Studies of Fe_2O_3-K_2O Based Catalysts for Ethylbenzene Dehydrogenation

利用穆斯堡尔谱在k2 O fE2 O3催化剂中检出了α fE2 O3(大晶粒及微晶 )、kfEO2 、k1+ XfE11O17、α fEOOH和γ fEOOH等物相 ,它们的相对含量取决于催化剂的含钾量及煅烧温度 ,相对含量的改变导致样品的穆斯堡尔谱图出现了复杂的变化 .与Xrd相比 ,穆斯堡尔谱可对钾与氧化铁的相互作用进行更有效的表征 ,穆斯堡尔谱和TPr研究都表明钾可延缓催化剂中fE(III)的被还原 .Fe 2O 3 K 2O Catalysts with different content of K 2O and calcined at different temperature were characterized by using Mssbauer spectroscopy.It was found from the experiments that only a sextuplet assignable to Fe 3+ of α Fe 2O 3 could be detected while the K 2O content in these catalysts were lower than 5%and the calcination temperature was below 900℃;and complex spectra ,which could be fitted with several sextuplets of trivalent irons present in α Fe 2O 3, KFeO 2, K 1+ x Fe 11 O 17 and α FeOOH ,and a doublet of Fe 3+ in γ FeOOH ,would be observed if the K 2O content were 10%～27%and the calcination temperature were 800～900℃.The γ FeOOH,as a hydrous iron oxide ,was the decomposition product of KFeO 2 which was strong hydroscopic by absorbing moisture from the atmosphere.The results also suggested that Mssbauer spectroscopy was a better mean than XRD for the characterizations of Fe 2O 3 K 2O catalysts,by which ,α FeOOH ,γ FeOOH and α Fe 2O 3 in amorphous or crystallite forms ( unable to be found by XRD ) could be detected .It was also shown from the Mssbauer spectroscopy and a TPR studies that potassium could retard the reduction of Fe(III) to Fe(II) in the Fe 2O 3 K 2O catalysts.中国石油化工总公司资助项

On the Cations-doped Study of High Tc Superconductor in Bi-system(I)── The Structure and Superconductivity of the Superconductor with Doping Binary Cations,Al─Pb,Mg─Pb and Mn─Pb etc.

讨论了Al-Pb，Mg-Pb和Mn-Pb等二元阳离子掺杂对bI系高T_C超导相出现时间的影响。试验中发现，前人较少讨论的Mg--（3＋）或Al--（3＋）离子在高T_C相形成时，进入到高T_C超导体晶格的特定位置，它们在高T_C超导相中起着各自不同的作用机制，从而影响了高T_C超导相的结构和超导电性。结果表明，Mg-Pb，Al-Pb和Mn-Pb等二元阳离子的掺杂是加快高T_C超导相形成和提高bI系高T_C超导相超导电性的有效途径，它们的掺杂有利于bI系高T_C相的形成。In this paper,it is discussed that the eFFect of doping binary cations, Mg-Pb, Al-Pb and Mn-Pb etc.on the time of the appearance of high Tc phase in superconductor of Bi-system.In this experiment,we Find that cations of Al3+ and Mg2+ have inserted into certain positions of the crystal lattice of high Tc phase,which has rarely been discussed in literature beFore,they respectively play important roles in the Formation of high Tc phase in Bisystem,and have an eFFect on the structure of high T.phase and the superconductivity.As a result of these, the doping binary cations, Mg-Pb, Al-Pb and Mn-Pb etc.,speed up the Formation of high Tc phase and raise the superconductivity.The doping is very Favorable For the Formation of high Tc phase

DOPING AND HIGH Tc Bi SYSTEM SUPERCONDUCTING CERAMICS

本文探索了bI系超导体2223相形成时,Al,Cr,Mg和Mn对高TC超导相的形成,结构和超导电性的关系,实验证明,掺杂有利于高TC相的形成,有利于提高超导电性。In present paper the eFFect of doping some elements on the Formation of the 2223 phase in Bi-system superconductors and their relationship to the superconductivity, were investigated.The experiment showed doping with those cation is beneFit of 2223 phase Formation of Bi - system high Tc superconductor, beneFiting to enhance the superconductivity of 2223 phase

XRD Characterization of Interaction between Potassium Promoter and Magnetite

XRD研究表明 ,作为乙苯脱氢催化剂中的氧化铁活性组分 ,具有反式尖晶石结构的Fe3O4 比刚玉型的α Fe2O3 更易与钾助催化剂发生相互作用 :α Fe2O3-K2O需经850℃煅烧才能生成多铁酸钾 ,但在Fe3O4 -K2O体系中只需700℃即可.而且 ,钾还可抑制Fe3O4 被氧化为α Fe2O3 的进程 ,在空气中 ,Fe3O4 只需300℃煅烧即可明显转化为α Fe2O3 ,但同样的转化在Fe3O4 K2O体系中要经700℃煅烧才会明显地发生.实验结果表明 ,某种形态的多铁酸钾可能是催化剂中的储钾相.Interactions of the potassium promoter with different kinds of iron o xide as the active component of the catalyst for ethylbenzene dehydrogenation we re investigated and compared with each other.By means of XRD method,it was found that magnetite in the form of the inverse spinel structure interacted easily wi th the potassium promoter to form potassium polyferrate in comparison to hematit e with the corundum structure.In the Fe3O4 K2O system,the phase of potassium po lyferrate could be formed at temperature of ～700℃,while for the α Fe2O3 K2 O system,the temperature as high as ～850℃was required for the formation of the potassium polyferrate phase.Moreover,incorporation of the potassium promoter in to the magnetite(Fe3O4) would be in favor of inhibiting the oxidation of Fe3O4 t o α Fe2O3 in the process of calcination in air,as evidenced by the experimenta l fact that pure Fe3O4 could be converted into α Fe2O3 by calcination in air a t a temperature as low as ～300℃,whereas for the system of Fe3O4 K2O (10％),a calcination temperature not lower than ～700℃was required for realizing this co nversion.Thus,it could be suggested that the potassium polyferrate was probable to serve as a storage phase for potassium in the catalyst of ethylbenzene dehydr ogenation to styrene.中国石油化工集团公司资

R&D on Octacosanol as A New Health Food Additives

以国产天然蔗蜡，蜂蜡及虫蜡为原料，寻求获得二十八烷醇的最佳工艺条件.Isolation of octacosanol from natural materials such as cane wax, bee wax and shellac wax etc is reported.Optimum process conditions were established for obtaining octacosanol in a content of 41.3% and yield of 9%

Mossbauer spectroscopic studies of Fe2O3-K2O-based catalysts for ethylbenzene dehydrogenation

Fe2O3-K2O Catalysts with different content of K2O and calcined at different temperature Mere characterized by using Mossbauer spectroscopy. It was found from the experiments that only a sextuplet assignable to Fe3+ of alpha-Fe2O3 could be detected while the K2O content in these catalysts were lower than 5% and the calcination temperature was below 900 degrees C; and complex spectra, which could be fitted with several sextuplets of trivalent irons present in alpha-Fe2O3, KFeO2, K1+xFe11O17 and alpha-FeOOH, and a doublet of Fe3+ in gamma-FeOOH, would be observed if the K2O content were 10% similar to 27% and the calcination temperature were 800 similar to 900 degrees C. The gamma-FeOOH, as a hydrous iron oxide, was the decomposition product of KFeO2 which was strong hydroscopic by absorbing moisture from the atmosphere. The results also suggested that Mossbauer spectroscopy was a better mean than XRD for the characterizations of Fe2O3-K2O catalysts, by which, alpha-FeOOH, gamma-FeOOH and alpha-Fe2O3 in amorphous or crystallite forms ( unable to be found by XRD) could be detected. It was also shown from the Mossbauer spectroscopy and a TPR studies that potassium could retard the reduction of Fe(III) to Fe(II) in the Fe2O3-K2O catalysts