Mass-transfer kinetics of ytterbium extraction with sec-nonylphenoxy acetic acid

The extraction kinetics of ytterbium with sec-nonylphenoxy acetic acid (CA-100) in heptane have been investigated using a constant interfacial area cell with laminar flow. The influence of stirring speed and temperature on the rate indicated that the extraction rate was controlled by the experiment conditions. The plot of interfacial area on the rate showed a linear relationship. This fact together with the low solubility in water and strong surface activity of CA-100 at heptane-water interfaces made the interface the most probable locale for the chemical reactions. The influences of extractant concentration and hydrogen ion concentration on the extraction rate were investigated, and the forward and reverse rate equations for the ytterbium extraction with CA-100 were also obtained. Based on the experimental data, the apparent forward extraction rate constant was calculated. Interfacial reaction models were proposed that agree well with the rate equations obtained from experimental data.

Advances in ionic conductive polymer electrolytes

The history of solid state electrolyte, the categories, ion transport mechanism, characterization, and the methods to raise the ionic conductivities of polymer electrolytes are reviewed. The further required attentions in the development of polymer electrolytes are discussed in the final part of the review.

A new crystal modification of gutta percha

Single chain and pauci chain single crystals of gutta percha in nanometer size were prepared by a dilute solution spraying method. A new crystal modification of gutta percha was found. The unit cell of the new modification of gutta percha was determined by electron diffraction crystal structure analysis to be a hexagonal form with cell dimensions: a = b = 0.695 nm, c = 0.661 nm, alpha = beta = 90 degrees, gamma =120 degrees; the space group is P6. The molecular packing in the unit cell was determined by computer modelling with Cerius(2) 2.0 software. (C) 1998 Elsevier Science Ltd. All rights reserved.

Study on diffusion of electroactive species in polyelectrolyte polyethylene glycol lithium perchlorate by chronoamperometry at a microdisk electrode

The mass transport dynamics of Ferrocene in polyelectrolyte polyethylene glycol lithium perchlorate (PEG . LiClO4) was studied by using chronoamperometry at a microdisk electrode. Chronoamperometry is a powerful method for the study of mass transport in polyelectrolyte, it has many advantages over the conventional methods at a microelectrode and the steady-state method at an ultramicroelectrode. By using this method the apparent diffusion coefficient D-app and concentration C-a of the electroactive species, can be estimated from a single experiment without previous knowledge of either one. We have estimated D-app and C-a of ferrocene in PEG . LiClO4 polyelectrolyte from 25 degrees C to 75 degrees C. The dependence on the concentration of electroactive species was observed. The diffusion coefficients decrease with increasing ferrocene concentration and decreasing temperature. The mass transport mechanism is explained, by using a free volume model.

Conversion from electronic conducting phase to redox conducting phase of polypyrrole

Square-wave voltommetry is used to study the oxidation of polypyrrole doped with dodecylsulfate. The net current curve in this experiment shows why the oxidation current does not display the capacitive-like shape common in cyclic voltammetry. In cyclic voltammetry, the redox behavior of polypyrrole is attributed to the size of dodecylsulfate, irreversible incorporation and the complete consumption of dodecylsulfate. After the polypyrrole film was scanned in aqueous NaCl solution, square wave voltammetric measurements show different results, indicating the change of the polymer nature with regard to the charge transport. This is explained by anion replacement, exclusion and the change of the charge transport mechanism.

Sedimentary processes and development of the Zenisu deep-sea channel, Philippine Sea

Zenisu deep-sea channel originated from a volcanic arc region, Izu-Ogasawara Island Arc, and vanished in the Shikoku Basin of the Philippine Sea. According to the swath bathymetry, the deep-sea channel can be divided into three,segments. They are Zenisu canyon, E-W fan channel and trough-axis channel. A lot of volcanic detritus were deposited in the Zenisu Trough via the deep-sea channel because it originated from volcanic arc settings. On the basis of the swath bathymetry, submersible and seismic reflection data, the deposits are characterized by turbidite and debrite deposits as those in the other major deep-sea channels. Erosion or few sediments were observed in the Zenisu canyon, whereas a lot of turbidites and debrites occurred in the E-W channel and trough axis channel. Cold seep communities, active fault and fluid flow were discovered along the lower slope of the Zenisu Ridge. Vertical sedimentary sequences in the Zenisu Trough consist of the four post-rift sequence units of the Shikoku Basin, among which Units A and B are two turbidite units. The development of Zenisu canyon is controlled by the N-S shear fault, the E-W fan channel is related to the E-W shear fault, and the trough-axis channel is related to the subsidence of central basin.

砂泥岩储层测井产能预测方法研究

Productivity prediction is very important in the exploration and development of oilfields. Using well log data to predict productivity is a front-line technology， which is key issue in petroleum exploration phase. The essential factors of productivity prediction is building practical models and correcting various causes to improve precision of prediction parameters. Any errors of parameters selections can affect the calculation of productivity prediction; therefore， how to improve research means and calculation accuracy is an important task of productivity prediction. Theory and case examples are deeply and comprehensively studied in the paper. Based on the theory of mud-filtrate invasion and experimental results， the damage of drilling， cementing， perforating，acidizing and fracturing were investigated. The damage depth was quantitatively evaluated by log data， based on this， the processing results of reservoir sensitivity were used to analysis quantitatively the damage of reservoir. The productivity prediction and reservoir damage were initiatively incorporated according to well logging， and the precision of productivity prediction was effectively improved. The method of NMR was explored to calculate the fluid viscosity on the basis of reservoir physical method， and the differences between the two methods were compared in the paper. From the theory fluid flow in porous media， various of theoretical models of production prediction were explored and several practical models were consided， such as productivity index method， improved productivity index method， improved Bearder method， SVM and so on. The characteristic and the application scope of these methods were studied. The inflow productivity and outflow productivity were incorporated and nodal analysis method was used to forecast wellhead yield， thus achieved scientifically production. On the applied background of conventional logging suite， the applying of special items or new logging method which is practical in the research area were studied， the logging suite was further optimized， and the precision of forecast was improved. On the basis of the modeling and the calculation of parameters， these methods were verified and analyzed， and the reconstruct principle was also built for block reservoir. The research block was processed by these methods and compared with testing data. Based on above the research， a technological system which is practical for shaly sand profiles in Shengli Oilfield was built. The system can reach commercialized degree，and satisfied the need of exploration and development of the oilfield.

束鹿凹陷泥灰岩储层综合评价与加砂压裂技术研究与应用

Luo Ning ( Mineralogy, Petrology, Deposit Mineralogy) Directed by Fu Liyun With the increase of the level of exploration and development, North China field, as one of the maturing fields in the east, has gradually turned their prospecting targets to frontiers such as deep zones, lithologic hydrocarbon reservoirs, low permeable layers, special lithostromes, etc, which propose new challenges to mating technique of exploration engineering. In it, the special lithostrome of clay carbonate in Shu-Lu cave in Middle Flank exploration area locates in Es_3 generating rock. The area distribution is large, formation thickness is over 100 meters, the oil accumulation condition is excellent, prognostic reserves is over 80,000,000 tons, but how to effectively stimulate the special low permeable and fractured reservoir has become the bottle neck problem of stimulation and stable yields. In this thesis, through comprehensive evaluation and analysis of lithology, lithomechanics, hydrocarbon reservoir characteristics, the characteristics of fluid flow through porous medium and the stimulation measures in the past, we acquire new cognition of clay carbonate reservoirs, in addition, the research and application of first hydraulic fracturing has gained positive effect and formed commensurable comprehensive reservoir evaluation technique and mating engineering technique of hydraulic fracturing. The main cognitions and achievements are as follows: 1.Study of geological information such as lithololy analysis and nuclear magnetic logging, etc, indicates that clay carbonate formation of Shu-Lu cave is anisotropic, low permeable with high shale content, whose accumulation space gives priority to microcracks. 2.The analysis of lithomechanics of clay carbonate indicates that the hardness is moderate, Young’s modulus is between that of sandstone and limestone, clay carbonate presents plastic property and its breakdown pressure is high because of the deep buried depth. 3.The analysis of the drillstem test curves indicates that the flow and build-up pressure curve of clay carbonate of Shu-Lu cave mainly has three types: formation contamination block-up type, low permeable type, formation energy accumulation slowness type; the reservoir characteristics presents double porosity media, radial compounding, uniform flow vertical fracture, isotropy, moniliform reservoir type. The target well Jingu 3 belongs to moniliform reservoir type. 4.Through recognition and re-evaluation of the treatment effect and technologic limitations of acidizing, acid fracturing and gelled acidizing in the past, based on the sufficient survey and study of hydraulic fracturing home and abroad, combined with comprehensive formation study of target well, we launched the study of the optimization of hydraulic fracturing technique, forming the principal clue and commensurable mating technology aimed at clay carbonate formation, whose targets are preventing leak off, preventing sand bridge, preventing embedment, controlling fracture height, forming long fracture. 5. Recognition of stimulation effect evaluation.

滑坡型泥石流转化机理研究—以四川省达县青宁乡滑坡为例

Slide-debris flow is debris flow which is transformed from landslide consecutively in a short time, it comprises of two phases: First, Landslide starts to slide; Second, landslide changes to debris flow. Slide-debris flow which brings great property and life loss happens frequently at home and abroad. In order to forecast the happening possibility and scope of slide-debris flow, transfromation mechanism of Slide-debris flow must be studied. Research on transformation mechanism of slide-debris flow is intersectant science of landslide kinetics and debris flow starting theory, It is a fringe problem as well as front problem of geological hazard. This paper takes Qingning slide-debris flow in Da County, Sichuan Province for example and has studied the mechanism of its instability and transfromation into debris flow through indoor test (including usual soil test and ring shear test) and digital modeling method.The research gets the following conclusions. Qingning Landslide took place mainly because of confined water head arising from rainfall infiltration. Before Landslide occurring, it rained continuously for 22 days, accumulated precipitation arrived at 521.6mm.Investigation shows that strata of Qingning Landslide contains quaternary loose accumulation, slip soil and highly weathered bedrock, which is a good condition for formation of confined water in the slope. Further more, groundwater seepage in the slope body and corresponding slope safety factor before landslide occurring have been computed through finite element method. The result shows that because of infiltration of rainfall, confined water head in the slope arose sharply, accordingly, the safety factor of the slope declined quickly. The result also shows that force put on the slide body by the rock mass detached from Dazhaiyan mountain was the direct factor for landslide occurring. Qingning slide-debris transformation mode has been summarized, the process the landslide changed into debris flow is divided into three phases in the prospective of macroscopic geological condition: landslide occurring, transformation and debris flow. Landslide occurring phase is from slope’ local creeping slide to Landslide occurring; transformation phase contains slide body sliding on the slide bed after slide occurring and sliding on the slope after shearing opening; debris flow phase is that slide body breaks up completely and flows downward into the ditches. The transformation mechanism of Qingning slide-debris flow has been studied through indoor ring shear test of slip soil. The result shows that transformation mechanism contains two points: first, during slide body sliding on the slide bed and slope after shearing opening, shearing shrinkage, grain crushing and grain layering brought about declining of its volume and produced excess pore water pressure, and because producing velocity of excess pore water pressure is much greater than its dissipating velocity, shear strength of slide body decreased sharply because of accumulated pore water pressure. Second, grains crushing and grains layering during slide body sliding brought about thick liquefied layer at the bottom of the slidebody, liquefied layer contained high water content and its shear strength was very low, its thickness increased as the sliding displacement increasing. Liquefied layer makes slide body sliding fast and easily break down to debris flow. Excess pore water pressure and liquefied layer made shear strength of slidebody became very low, furthermore, water in the pit of slope joining in the slidebody was also a facter that made slidebody accelerate the transformation. Influence of slide body thickness and fine grains content to transformation of slide-debris flow has been studied through ring shear test. The result reaches two conclusions. First, thickness of slide body affects transformation of slide-debris flow by two ways, porewater pressure and effect of “soft base” increases as thickness of slide body increasing.so the thicker slide body is ,the easier transformation is. Second, actual dissipating velocity of porewater pressure should be considered when studying the influence of fine grains content to tranformation of slide-debris flow. There should be a critical content of fine grains which makes the difference of producing and dissipating velocity of water pore pressre greatest, this value is the best for slide-debris transformation. The whole process of slide-debris flow transformation is reproduced through discrete element method. Transformation mechanism of slide-debris flow is studied through monitoring various parameters including pore water pressure, grain crushing and grain layering in the slide body during the transformation. The result confirms and supplements the transformation mechanism of slide-debris flow got from ring shear test well.

东濮凹陷文－桥－白地区异常高压储层沉积成岩特征及成因初探

In Dongpu depression, there are obviously overpressure phenomena below 2000-3200m. Research to the relationship between sedimentation-diagenesis and overpressure of reservoirs is in great need. In this paper, after analyzing and simulating the overpressure in Wendong, Qiaokou and Baimiao regions, we draw a conclusion that the fast sedimentation since Low Tertiary is one of the most important mechanisms for the formation of overpressure in Dongpu Depression. The gypsum in northern part of Dongpu Depression is the good seal for the development of overpressure. On the base of detailed work to the distribution and magnitude of overpressure in Wen-qiao-Bai regions, we selected several wells that have different overpressure to find the sedimentary and diagenetic differences of these wells. We find that compaction is obviously inhibited in overpressured reservoirs, which results in the linear relation between physical properties of reservoirs and sedimentary parameters, such as sorting coefficient, the content of matrix, etc. Reservoirs with great magnitude of overpressure have undergone more extensive erosion than the ones with low magnitude of overpressure, which probably is the result of the great solubility of CO_2 under high pressure. The great burial depth, the high content of matrix and the extensively developed cement of carbonate are the most important factors that influence the physical properties of reservoirs in Dongpu depression. Overpressure plays a constructive role in the physical properties of reservoirs. the overpressured reservoirs of Es_3~3 subsection in Wendong region are probably the ones that have good physical properties. From homogenetic temperatures that obtained form the fluid inclusions in quartz overgrowth, we find that there were 4 episodes of fluid flows in Dongpu depression. In conjunction with the analysis of the burial history of overpressured reservoirs, we draw conclusions that the first, second and third episodes of fluid flows took place in the extensive rifting stage of Dongpu Depression, the burial depth when the first episode of fluid flow took place was about 1500m, the age was about 36 my; the burial depth of the second and third episodes of fluid flow was between 1800-3000m at that time, the age was between 35-28my. The fluid flows of the second, third, and fourth episodes were in close relation to the overpressure and maybe were the results of the episodic hydrofracturing of overpressured mudstones and shales. The episodic fluid flow of overpressured mudstones and shales probably facilitates the cementation of carbonate, which decreases the physical properties of overpressured reservoirs. The dolomites and ferrodolomites maybe the products of the episodic hydrofracturing of overpressured mudstones and shales.

黄东海及朝鲜海峡冰后期陆架沉积物的环境磁学研究

There are four chapters in this dissertation. The first chapter briefly synthesizes the basic theories, methods and present-day applying situation of environmental magnetism. The second chapter probes into the magnetic mineral diagenesis in the post-glacial muddy sediments from the southeastern South Yellow Sea and its response to marine environmental changes, using the muddy sediment of Core YSDP103 formed in the shelf since about 13 ka BP. The third chapter illustrates the high-resolution early diagenetic processes by investigating the rapidly deposited muddy sediments during the last 6 ka in Cores SSDP-102 and SSDP-103 from the near-shore shelf of Korea Strait. The fourth chapter presents the results of detailed rock magnetic investigation of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea in an attempt to provide environmental magnetic evidence for the provenance of the fine-grained deposit. Core YSDP103 was retrieved in the muddy deposit under the cold eddy of the southeastern South Yellow Sea, and the uppermost 29.79 m core represents the muddy sediments formed in the shelf since about 13 ka BP. The lower part from 29.79 to 13.35 m, called Unit A2, was deposited during the period from the post-glacial transgression to the middle Holocene (at about 6 ~(14)C ka BP) when the rising sea level reached its maximum, while the upper part above 13.35 m (called Unit Al) was deposited in a cold eddy associated with the formation of the Yellow Sea Warm Current just after the peak of post-glacial sea level rise. For the the uppermost 29.79 m core, detailed investigation of rock-magnetic properties and analyses of grain sizes and geochemistry were made. The experimental results indicate that the magnetic mineralogy of the core is dominated by magnetite, maghemite and hematite and that, except for the uppermost 2.35 m, the magnetic minerals were subject to reductive diagenesis leading to significant decline of magnetic mineral content and the proportion of low-coercivity component. More importantly, ferrimagnetic iron sulphide (greigite) is found in Unit A2 but absent in Unit Al, suggesting the control of marine environmental conditions on the magnetic mineral diagenesis. Magnetic parameters show abrupt changes across the boundary between the Unit Al and A2, which reflects a co-effect of environmental conditions and primary magnetic components of the sediments on the diagenesis. Alternating zones of high and low magnetic parameters are observed in Unit A2 of Core YSDP103, which is presumably due to periodic changes of the concentration and/or grain size of magnetic minerals carried into the study area. Cores SSDP-102 and SSDP-103, two studied sediment cores from the Korea Strait contain mud sequences (14 m and 32.62 m in thickness) that were deposited during the last 6,000 years. Analyses of grain sizes and geochemistry of the cores have demonstrated that the sediments have uniform lithology and geochemical properties, however, marked down-core changes in magnetic properties suggest that diagenesis has significantly impacted the magnetic properties. An expanded view of early diagenetic reactions that affect magnetic mineral assemblages is evident in these rapidly deposited continental shelf sediments compared to deep-sea sediments. The studied sediments can be divided into four descending intervals, based on magnetic property variations. Interval 1 is least affected by diagenesis and has the highest concentrations of detrital magnetite and hematite, and the lowest solid-phase sulfur contents. Interval 2 is characterized by the presence of paramagnetic pyrite and sharply decreasing magnetite and hematite concentrations, which suggest active reductive dissolution of detrital magnetic minerals, the absolute minimum abundance of magnetite is reached at the end of this interval. Interval 3 is marked by a progressive loss of hematite with depth, and at the base of this interval, 82% to 88% of the hematite component was depleted and the bulk magnetic mineral concentration was reduced to the lowest value in the entire studied mud section. Interval 4 has an increasing down-core enhancement of authigenic greigite, which is interpreted to have formed due to arrested pyritization resulting from consumption of pore water sulfate with depth. This is the first clear demonstration from an active depositional environment for a delay of thousands of years for acquisition of a magnetization carried by greigite. This detailed view of diagenetic processes in continental shelf sediments suggests that studies of geomagnetic field behavior from such sediments should be conducted with care. Paleoceanographic and paleoclimatic studies based on the magnetic properties of shelf sediments with high sedimentation rates like those in the Korea Strait are also unlikely to provide a meaningful signature associated with syn-depositional environmental processes. The rock magnetic properties of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea, an area surrounded by sands, are investigated with a view to providing information on the sediment provenance. Multiple magnetic parameters such as magnetic susceptibility (%), anhysteretic remanent magnetization (ARM), saturation rernanent magnetization (SIRM), coercivities of SIRM (Her), and S ratios (relative abundance of low-coercivity magnetic minerals) are measured for all 179 surface samples, and partial representative samples are examined for their magnetic hysteresis parameters, temperature-dependence of magnetic susceptibility and x-ray diffraction spectra. Our research indicates that the magnetic mineralogy is dominated by magnetite with a small amount of hematite and is primarily of pseudo-single domain (PSD) to multidomain (MD) nature with a detrital origin. In the surface sediments, the granulometry of magnetic fractions is basically independent of grain sizes of the sediment containing the magnetic grains, and the composition of magnetic minerals remains almost homogeneous, that is, with a relatively constant ratio of low to high coercivity fraction throughout the area. The magnetic concentration in the study area generally decreases to the east or southeast accompanied by magnetic-particle fining to the east or to the northeast. The geographic pattern of magnetic properties is most reasonably explained by a major source of sediment jointly from the erosion of the old Huanghe River deposit and the discharge of the Changjiang River. The rock magnetic data facilitate understanding of the transport mechanism of fine-grained sediments in the outer shelf of the East China Sea.

胜利油田低渗透砂岩油藏非均质地质建模

Guided by geological theories, the author analyzed factual informations and applied advanced technologies including logging reinterpretation, predicting of fractal-based fracture network system and stochastic modeling to the low permeable sandstone reservoirs in Shengli oilfield. A new technology suitable for precious geological research and 3D heterogeneity modeling was formed through studies of strata precious correlation, relation between tectonic evolution and fractural distribution, the control and modification of reservoirs diagenesis, logging interpretation mathematical model, reservoir heterogeneity, and so on. The main research achievements are as follows: (1) Proposed four categories of low permeable reservoirs, which were preferable, general, unusual and super low permeable reservoir, respectively; (2) Discussed ten geological features of the low permeable reservoirs in Shengli area; (3) Classified turbidite fan of Es_3 member of the Area 3 in Bonan oilfield into nine types of lithological facies, and established the facies sequences and patterns; (4) Recognized that the main diagenesis were compaction, cementation and dissolution, among which the percent compaction was up to 50%~90%; (5) Divided the pore space in ES_3 member reservoir into secondary pores with dissolved carbonate cement and residual intergranular pores strongly compacted and cemented; (6) Established logging interpretation mathematical model guided by facies- control modeling theory; (7) Predicted the fracture distribution in barriers using fractal method; (8) Constructed reservoir structural model by deterministic method and the 3D model of reservoir parameters by stochastic method; (9) Applied permeability magnitudes and directions to describe the fractures' effect on fluid flow, and presented four different fractural configurations and their influence on permeability; (10) Developed 3D modeling technology for the low permeable sandstone reservoirs. The research provided reliable geological foundation for the establishment and modification of development plans in low permeable sandstone reservoirs, improved the development effect and produced more reserves, which provided technical support for the stable and sustained development of Shengli Oilfield.

Retention behavior of hydrophobic organic chemicals as a function of temperature in soil leaching column chromatography

To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in soil/solvent system, a soil leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20-40 degreesC was carried out, which utilized a reference soil (SP 14696) packed column and a methanol-water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 degreesC (k'(30)/k'(40)) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C-18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability-dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former. (C) 2002 Elsevier Science Ltd. All rights reserved.

Capillary electrochromatography with monolithic poly(styrene-co-divinylbenzene-co-methacrylic acid) as the stationary phase

A new kind of monolithic capillary electrochromatography column with poly(styrene-co-divinylbenzene-co-methacrylic acid) as the stationary phase has been developed. The stationary phase was found to be porous by scanning electron microscopy and the composition of the continuous bed was proved by IR spectroscopy to be the ternary polymer of styrene, divinylbenzene, and methacrylic acid. The effects of operating parameters, such as voltage, electrolyte, and organic modifier concentration in the mobile phase on electroosmotic flow were studied systematically, The retention mechanism of neutral solutes on such a column proved to be similar to that of reversed-phase high performance liquid chromatography. In addition, fast analyses of phenols, chlorobenzenes, anilines, isomeric compounds of phenylenediamine and alkylbenzenes within 4.5 min were achieved.

The synergic effect between Mo species and acid sites in Mo/HMCM-22 catalysts for methane aromatization

The acid properties of Mo/HMCM-22 catalyst, which is the precursor form of the working catalyst for methane aromatization reaction, and the synergic effect between Mo species and acid sites were studied and characterized by various characterization techniques. It is concluded that Bronsted and Lewis acidities of HMCM-22 are modified due to the introduction of molybdenum. We suggest a monomer of Mo species is formed by the exchange of Mo species with the Bronsted acid sites. On the other hand, coordinate unsaturated sites (CUS) are suggested to be responsible for the formation of newly detected Lewis acid sites. Computer modelling is established and coupling with experimental results, it is then speculated that the effective activation of methane is properly accomplished on Mo species accommodated in the 12 MR supercages of MCM-22 zeolite whereas the Bronsted acid sites in the same channel system play a key role for the formation of benzene. A much more pronounced volcano-typed reactivity curve of the Mo/HMCM-22 catalysts, as compared with that of the Mo/HZSM-5, with respect to Mo loading is found and this can be well understood due to the unique channel structure of MCM-22 zeolite and synergic effect between Mo species and acid sites.