• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Synthesis of ZSM-22/ZSM-23 intergrowth zeolite as the catalyst support for hydroisomerization of n-hexadecane

    2021-06-02 14:01:42SONGChengyeMENGJipengLIChuangZEYAODONGPahaerLIANGChanghai
    燃料化學(xué)學(xué)報(bào) 2021年5期

    SONG Cheng-ye,MENG Ji-peng,LI Chuang,*,ZEYAODONG Pahaer ,LIANG Chang-hai,*

    (1.State Key Laboratory of Fine Chemicals& Laboratory of Advanced Materials and Catalytic Engineering,School of Chemical Engineering, Dalian University of Technology, Dalian 116024,China;2. Dushanzi Petrochemical Company, PetroChina Company Limited, Karamay 833699,China)

    Abstract:ZSM-22/ZSM-23 intergrowth zeolite was successfully synthesized by hydrothermal method with diethylamine and dimethylamine as co-structure directing agents at a dimethylamine/diethylamine molar ratio of 24.The physicochemical properties of ZSM-22/ZSM-23 intergrowth zeolite including the crystallinity,crystal morphology, texture and acidity were determined by XRD,FE-SEM,TEM, N2-physisorption, NH3-TPD,Py-FTIR,and so on;the performance of Pt/ZSM-22/ZSM-23 catalyst prepared by impregnation in the hydroisomerization of n-hexadecane was then investigated.The results indicate that the ZSM-22/ZSM-23 intergrowth zeolite displays the needle-like morphology with the topological structures of both ZSM-22 and ZSM-23,which is rather different from pure ZSM-22 and ZSM-23 and their mechanical mixture.After loading 0.5%Pt,the bi-functional Pt/ZSM-22/ZSM-23 catalyst exhibits excellent performance in the hydroisomerization of n-hexadecane,with a much higher yield of i-C16 products(dominated by mono-branched isomers)than those obtained over Pt supported on ZSM-22 and ZSM-22 and their mechanical mixture.

    Key words:ZSM-22/ZSM-23;intergrowth zeolite;n-hexadecane;hydroisomerization CLC number:O643.32 Document code: A

    Nowadays,hydroisomerization has become one of the most important catalytic conversion processes in the petrochemical industry due to the increasingly stringent environmental regulations.By convertingn-alkanes toiso-paraffins, hydroisomerization can increase the octane number of gasoline,lower the pour point of diesel and improve the viscosity-temperature properties of lubricant base oils[1].Bifunctional catalysts with acid sites for isomerization and metal centers for hydrogenation/dehydrogenation are widely used for the hydroisomerization ofn-alkanes[2].In this regard,zeolites have been extensively used as the supports for the bifunctional catalysts[3].Recently, plentiful studies have shown that various zeolites such as ZSM-48[4],ZSM-22[5], SAPO-11[6]and ZSM-23[7]exhibited excellent catalytic performance in the hydroisomerization ofn-alkane,as their one-dimensional 10-membered ring elliptical straight pore channels are comparable in size to the kinetic diameter ofn-alkane[8].In general,the zeolites used as the catalyst supports have a single structure[9].However,given the better adaptability of complex fractions,composite[10],mixed and intergrowth zeolites in particular are nowadays considered as favored catalyst supports for various applications[11].

    ZSM-22 zeolite has TON topology, with a pore size of 0.46 nm×0.57 nm[12], whilst ZSM-23 of MTT topology has a pore size of 0.45 nm×0.52 nm[13].Since both ZSM-22 and ZSM-23 zeolites have identical basic structural units,the intergrowth zeolites could be synthesized under specific conditions.Cocrystallization could change the cell parameters and the pore channel structure of the original single zeolites,thus affecting the catalytic performance.ZSM-22/ZSM-23 intergrowth zeolite was first reported in 1999 with different pore structures and acidities[14].Lateef et al[15]successfully synthesized the ZSM-22/ZSM-23 intergrowth zeolite and named it as SSZ-54, with the composition of 30%ZSM-22/70%ZSM-23.Wang et al[16]proposed a method to synthesize ZSM-22/ZSM-23 with a fixed proportion of 40%ZSM-22/60%ZSM-23.Burton et al[17]reported that single template agents and dual template agents can be both successfully used in the synthesis of ZSM-22/ZSM-23.However,most of the above researches have been confined to the synthesis of the intergrowth zeolite materials[18],whereas their catalytic performance in the hydroisomerization of long chainn-alkanes remains unclear.

    In this work, two small amines,dimethylamine(DMA)and diethylamine(DEA),were adopted as structure-directing agents(SDA)for the synthesis of ZSM-22/ZSM-23 via dynamic hydrothermal method.The synthesis conditions for ZSM-22/ZSM-23 were optimized. Various characterization techniques such as XRD,SEM,TEM, N2-physisorption,Py-FTIR and NH3-TPD were employed to determine the crystallinity,morphology and textural and acidic properties.The hydroisomerization ofn-hexadecane were then comparatively carried out over various Pt catalysts supported on ZSM-22,ZSM-23,ZSM-22/ZSM-23 intergrowth and their mechanical mixture,to reveal the catalytic advantage of ZSM-22/ZSM-23 intergrowth.

    1 Experimental

    1.1 Chemical and materials

    Silica sol(40%,LUDOX HS-40)and fumed silica(SiO2,%,Wacker)were used as the silicon sources and aluminum sulfate(Al2(SO4)3·18H2O,AR,Aladdin)and sodium aluminate(NaAlO2,AR,Macklin)as the aluminum sources.The rest chemicals used in this work include sodium hydroxide(NaOH, AR,Tianjin Kermel), potassium hydroxide(KOH,AR,Tianjin Kermel),dimethylamine(DMA,C2H7N,33%,Sinopharm),diethylamine(DEA,C4H12N,AR,Sinopharm),pyrrolidine(PY,(CH2)4NH,AR,Sinopharm),isopropylamine(IPA,C3H9N,CP,Sinopharm),1,6-diaminohexane(DAH,C6H15N2,AR,Sinopharm), andn-hexadecane (C16H34, GC, Sinopharm).

    1.2 Zeolite synthesis

    1.2.1ZSM-22/ZSM-23intergrowth zeolite

    The initial gel molar composition was 1 SiO2:(0.005?0.0125) Al2O3:aDMA :bDEA:(30?70) H2O:(0.05?0.4)OH?,wherea/b=24,a+b=0.4?1.Typically,9.26 g silica sol,0.25 g NaOH and 21.40 g deionized water were mixed to form gel A.Solution B formed by dissolving 0.41 g Al2(SO4)3·18H2O with deionized water was dropwise added to gel A.After half an hour of intense stirring,0.14 g DEA and 5.00 g DMA were added in sequence. When all ingredients in the three-necked flask were evenly dispersed, the mixture was transferred to an autoclave for dynamic crystallization(40 r/min)at 180°C for 66 h. After that,the product was dried,filtered and washed to obtain the Na-ZSM-22/ZSM-23 sample. After calcining at 550°C for 4 h to dislodge the structure directing agents, the zeolite sample was placed in a 0.5 mol/L NH4NO3aqueous solution (30 mL per 1 g zeolite) at 80 °C for 2 h for ammonium ion exchange and the ion-exchange process repeated for three times.Lastly, the zeolite sample was calcined at 550°C for 3 h, to obtain the H-form H-ZSM-22/ZSM-23 intergrowth zeolite.

    1.2.2ZSM-22zeolite

    11.57 g silica gel was added to the solution of 2.42 g DAH,0.324 g KOH and 0.51 g Al2(SO4)3·18H2O,stirring to get the precursor synthesis gel with a molar composition of 1 SiO2∶0.01 Al2O3∶0.27 DAH∶36 H2O∶0.075 KOH.The products were transferred into a stainless steel reactor and the hydrothermally treated at 160°C for 48 h under rotational conditions.Following the same calcination and ion-exchange processes,HZSM-22 zeolite was then obtained.

    1.2.3ZSM-23zeolite

    The synthesis gel with the composition of 1 SiO2∶0.01 Al2O3∶0.25 PY∶0.75 IPA∶38 H2O∶0.08 NaOH was created in the alkaline environment with 0.14 g NaOH,4.37 g fumed silica,50 g deionized water,1.21 g PY,3.23 g IPA and 0.17 g NaAlO2. After crystallization for 96 h at 180°C and necessary calcination and ion-exchange processes,H-ZSM-23 zeolite was then produced.

    1.2.4Mechanicalmixtureof ZSM-22andZSM-23 zeolites

    ZSM-22 and ZSM-23 with a mass ratio of ZSM-22/ZSM-23 being 40/60 were manually mixed to produce the mechanical mixture,donated as MZSM-22/ZSM-23.

    1.3 Preparation of the supported Pt catalysts

    The bifunctional supported Pt catalysts with a platinum loading of 0.5%were prepared via the impregnation method, with abovementioned zeolites in proton form as the supports.The support was impregnated with H2PtCl6solution(15 mL per 1 g zeolite)and then stirred for 7 h.After rotational drying,the products were heated at 400°C with a heating rate of 4°C/min in a mixed flow of Ar(30 mL/min)and O2(30 mL/min)for 3 h.

    1.4 Catalyst characterization

    Powder X-ray diffraction was carried out in the 2θrange of 5°?70°on a Rigaku Smartlab-9 kW(CuKα,40 kV,100 mA),to determine the purity and the relative crystallinity(RC).After spraying of gold,the morphology of the as-synthesized zeolites and catalysts was observed with a QUANTA 450 field emission scanning electron microscope(FE-SEM) produced by FEI Company of America.Transmission electron microscope(TEM)was conducted on Tecnai G2F30 STWIN.The actual molar ratio of SiO2/Al2O3(SAR)and the platinum loading were analyzed by using a Perkin-Elmer Optima 2000DV plasma atomic emission spectrometer (ICP-AES).

    NH3-TPD and Py-FTIR profiles were measured on CHEMBET-3000 and EQUINOX 55,respectively,to determine the acidity of different zeolites.For NH3-TPD, the zeolite sample,after pretreated in a He flow at 350°C for 2 h,were exposed to 10%NH3/He(40 mL/min)flow at 120°C for 30 min;after that,the sample was purged in a He atmosphere for 1 h and then heated with the heating rate of 10°C/min from 120 to 700 °C in a He flow. For Py-FTIR, the background spectra were recorded at room temperature after purging at 400°C for 40 min;allowing absorbing pyridine for 10 min,the samples were heated to 150,300 and 450°C,to collect the Py-FTIR spectra.

    The specific surface area, pore size distribution and pore volume of the prepared catalysts and zeolites were obtained on the Quantachrome Autosorb-iQ physisorption apparatus.All samples were calcined at 300°C for 12 h before the test.To calculate the dispersion and size of platinum particles on the bifunctional catalyst,CO-chemisorption was carried out on Micromeritics Autochem II 2920.Solid-state29Si and27Al MAS NMR investigations were carried out on Agilent DD2-500 MHz spectrometer to examine the surroundings of zeolite framework.

    1.5 Catalytic tests

    The catalytic tests ofn-hexadecane hydroisomerization were conducted in a fixed-bed reactor.0.15 g bifunctional platinum catalyst was diluted with 2 mL of 60?80 mesh quartz sand and placed in the center of reaction tube.3 mL of 40?60 mesh quartz sand was filled at each end of the tube to get a uniform flow without increasing the bed-side pressure drop.The catalyst was first reduced at 400°C in a hydrogen atmosphere for 3 h.After that,the reaction unit was adjusted to the desired conditions and the feedstock was pumped into the reactor; the catalytic performance was evaluated by varying the reaction temperature at a specific contact time.The reaction products condensed by the cold trap were collected for offline analysis,with an Agilent 7890A gas chromatograph (USA, HP-5 column, FID). The products were quantified by using an Agilent 7890B-5977A gas chromatography-mass spectrometer on an HP-5 column.

    2 Results and discussion

    2.1 Synthesis of ZSM-22/ZSM-23 zeolite with the dual-SDA of DMA and DEA

    The effects of various factors on the synthesis of ZSM-22/ZSM-23 intergrowth zeolite were investigated,such as the gel compositions(DMA/DEA,OH?/SiO2,H2O/SiO2),alkali sources,crystallization time and temperature.In general,an increase in the temperature could accelerate the crystallization[19].In the actual industrial production process,relatively higher crystallization temperatures were often used to shorten the crystallization time and to increase productivity.Therefore,a temperature of 180°C as reported in literature[20]was chosen to investigate the effect of crystallization time.Similarly,to provide more suitable acidic sites for the bifunctional catalysts[21],a SiO2/Al2O3ratio of 100 was selected[22],which also facilitated the synthesis of ZSM-22,ZSM-23 and their mechanical mixture.

    As presented in Table 1 and Figure 1,the XRD results indicate that the proportion of SDAs was a crucial factor in the synthesis of ZSM-22/ZSM-23 intergrowth zeolite.The ZSM-22/ZSM-23 intergrowth zeolite can only be synthesized directionally when the molar ratio of DMA/DEA is 24 and total SDAs/SiO2is 0.75.As ZSM-22 is a metastable substance,only a suitable SDA amount cannot guarantee the synthesis of intergrowth zeolite with a high crystallinity.As shown in Figure 1(b),an excessively long crystallization time leads to sufficient growth of cristobalite(21.7°)and zeolite with a wide synthetic interval such as ZSM-5[23].However,a short reaction time cannot allow a complete crystallization to form the ZSM-22/ZSM-23 intergrowth zeolite and highest relative crystallinity can be archived in the synthesis interval of 60?66 h.As a result,a crystallization time of 66 h was used subsequently for the synthesis of high purity ZSM-22/ZSM-23 intergrowth zeolite

    The type and amount of alkali source also have a significant influence on the synthesis of ZSM-22/ZSM-23 intergrowth zeolite. Moderate alkalinity can promote the formation of Si?O?Al fragments and accelerate both the nucleation and crystallization processes. At the same time, the metal cations act as the charge balance components for the zeolite framework, whereas the OH?anions play the role of mineralizer. As given in Table 1 and Figure 1(c), the relative crystallinity reaches a peak at an OH?/SiO2ratio of 0.1. A lower alkalinity may not sufficiently dissolve the silicon and aluminum sources, leading to the formation of amorphous and low-crystallinity samples, whereas excessive alkalinity may inhibit the growth of zeolite crystals, resulting in a lower yield of the desired product or a large amount of quartz phase. NaOH as the alkali source can get high crystallinity products,although KOH has a slightly wide synthesis interval.The amount of water is also an important factor for the crystallization, influencing the crystallinity and the yield of the as-synthesized zeolites. Less water leads to a decline in the purity of synthetic samples and the agglomeration of crystals, whereas too much water may reduce the concentration of the reactants, affecting the reaction rate and the yield of the single-vessel.Figure 1(d) and Table 1 demonstrate that an H2O/SiO2ratio of 45 is suitable. As a result, the ZSM-22/ZSM-23 intergrowth zeolite of high crystallinity was synthesized with an initial gel composition of 1 SiO2∶0.01 Al2O3∶0.72 DMA : 0.03 DEA∶45 H2O∶0.1 NaOH at 180 °C for 66 h.

    Table 1 Effect of gel composition and synthetic conditions on the crystallization products

    ZSM-22 zeolite belongs to the TON topology[24],whereas ZSM-23 to the MTT topology[25], both take the one-dimensional pore structure with the ten-membered ring. As shown in Figure 2,the XRD pattern of Pt/ZSM-22/ZSM-23 intergrowth zeolite is notably different from those of Pt/ZSM-22,Pt/ZSM-23 and Pt/MZSM-22/ZSM-23, where the characteristic diffraction peaks of ZSM-22 and ZSM-23 can be found at 20.32°,22.96°,24.1°,24.6°,and 25.76°.Even so,the ZSM-22/ZSM-23 intergrowth is not a simple addition of ZSM-22 and ZSM-23,nor is a hybrid zeolite that made up of arbitrary proportions.It has a new topology structure, with the basic structural unit of ZSM-22 and ZSM-23 in accordance with the specific crystallization way of intergrowth.By comparison with the Diffax simulations of random intergrowths of TON and MTT,it is ascertained that the as-synthesized intergrowth zeolite has a specific ratio of 40%TON+60%MTT[17].There is no typical peaks for metallic platinum at 39°,46°and 67°,indicating that the platinum particles are small and homogeneously dispersed on the zeolite supports[26].

    Figure 1 XRD patterns of the as-synthesized zeolite samples for the gel of 1 SiO2 :0.01 Al2O3:w DMA : x DEA : y H2O:m NaOH at 180°C for z h:(a) varying DMA/DEA ratio;(b) varying crystallization time;(c)varying NaOH amount;(d) varying water quantity

    Figure 2 XRD patterns of Pt/ZSM-22/ZSM-23,Pt/ZSM-22,Pt/ZSM-23 and Pt/MZSM-22/ZSM-23

    2.2 Physical properties of the zeolite samples

    Figure 3(a)demonstrates that the ZSM-22/ZSM-23 intergrowth zeolite has a uniformly distributed n eedle-like crystal morphology with a length of 0.5?1μm and a width of 0.08?0.12μm,consistent with those reported in the literature[27].In contrast,ZSM-22 displays homogeneous rod-shaped crystals with a length of 1?1.25μm and a width of 0.25μm(Figure 3(b))[28],whereas ZSM-23 is sheet-like with a length of 0.75?1.75μm(Figure 3(c))[29]. As an artificial mixture of ZSM-22 and ZSM-23 at a ratio of 40%?60%,its crystal morphology is uniformly interwoven with ZSM-22 and ZSM-23.Agglomeration was also observed in ZSM-22/ZSM-23,displayed with spheres with a diameter of 9?14μm;in contrast, the spheres in ZSM-23 are slightly smaller with a diameter of 8μm.The mechanical mixture of MZSM-22/ZSM-23 is just simply clumped together and has no fixed shape,whereas ZSM-22 is simply stacked together.

    Figure 3 FE-SEM images of (a)ZSM-22/ZSM-23,(b)ZSM-22,(c)ZSM-23 and (d)MZSM-22/ZSM-23

    The N2adsorption-desorption isotherms and pore size distribution of the as-synthesized zeolites and catalysts are depicted in Figure 4 and the corresponding textural properties are given in Table 2.The adsorption quantity of all the samples increases rapidly at low relative pressures,consistent with type I isotherms,typical for microporous materials[30,31]; the appearance of a typical platform period is due to the saturation of the microporous adsorptions[32].The pore size distribution of all zeolite samples(Figure 4(b))is mainly concentrated in the microporous region (< 2 nm).Except for ZSM-22,other three samples are relatively close in the specific surface areas(198?209 m2/g),probably due to their small particle size.All zeolite samples have a pore size of around 0.5 nm,corresponding to the typical orifice size of a zeolite with ten-membered ring channels[33].Compared to ZSM-22 and ZSM-23, the ZSM-22/ZSM-23 intergrowth has a larger total pore volume and microporous volume, proving the superior pore channel properties of the composite zeolites.After loading the metal Pt,the properties except total pore volume of all catalyst samples do not have significant change because of the high dispersion of the metal component;as measured by CO-chemisorption, the platinum particle sizes for Pt/ZSM-22/ZSM-23,Pt/ZSM-22,Pt/ZSM-23 and Pt/MZSM-22/ZSM-23 are 1.15,2.19,1.81 and 1.58 nm,respectively.The TEM images shown in Figure 5 further illustrate that the platinum particles are evenly dispersed on the zeolite supports and the platinum particle sizes measured by TEM remain consistent with the CO-chemisorption results.

    2.3 Chemical structural and acidic properties of the zeolite samples

    Figures 6 and 7 show the27Al NMR and29Si NMR spectra of four zeolite samples. All zeolites display two similar peaks, with a sharp peak at chemical shift 52 attributed to the tetracoordinated framework aluminum and a signal peak at chemical shift 0 to the extraframework six-coordinated aluminum[34].By calculating the signal intensities of the corresponding species, the non-skeletal aluminum species contents of the ZSM-22/ZSM-23,ZSM-22,ZSM-23 and MZSM-22/ZSM-23 samples are presented in Table 3.It demonstrates that most of the aluminum atoms are located in the zeolite framework[35,36].The distribution of aluminum atoms also has an influence on the acid properties of the zeolite.As shown in Figure 7,four distinct signal peaks are observed in the29Si NMR spectra at chemical shift?116,?113,?108 and?104.As reported in the literature[37],the peaks from chemical shift?113 to?116 are attributed to tetrahedral framework silicon atoms,connected to other silicon atoms by an oxygen bridge(4Si,0Al).The peak around chemical shift ?108 is associated with the framework silicon interacting with three silicon and one aluminum atom(3Si,1Al),where the Br?nsted acid site forms[38].Lower intensity resonance at chemical shift?104 corresponds to silicone hydroxyl,(2Si,2OH)or(3Si,1OH).ZSM-22 shows a significant shift for the peaks in the29Si NMR spectra compared to other samples,indicating a different chemical environment for Si in the zeolite structure[39].

    Figure 4 N2 adsorption-desorption isotherms and pore size distribution of various zeolites and catalysts

    Table 2 Textural properties of as-prepared zeolites and catalysts

    Meanwhile,the SiO2/Al2O3ratios of the four zeolites are essentially the same,slightly lower than that derived from the initial gel composition.It was propoably ascribed to the fact that when HF was used to dissolve the samples,a small part of silicon turned into gaseous SiF4and spilled out,resulting in a lower SiO2/Al2O3ratio measured by ICP.

    Figure 5 TEMimages of (a)Pt/ZSM-22/ZSM-23,(b)Pt/ZSM-22,(c)Pt/ZSM-23 and (d)Pt/MZSM-22/ZSM-23

    Figure 6 27Al MAS NMR spectra of (a)ZSM-22/ZSM-23,(b)ZSM-22,(c)ZSM-23,and (d)MZSM-22/ZSM-23

    When the zeolites are used as the catalyst support,as an important factor,acidity is closely associated with the catalytic activity and lifetime[40].The acidic characteristics can be determined by NH3-TPD[18],as shown in Figure 8.The NH3desorption curves can be divided into three peaks centered at 250?270,330?350 and 450?470°C,corresponding to the weak,medium and strong acid centers, respectively[41].All four zeolite samples display a large peak at low temperature,proving their abundant weak acid sites;the quantity of acid sites according to their strength can be estimated by the NH3desorption signals,as given in Table 3.Obviously, by the total acid amounts,four samples follows the order of ZSM-23>MZSM-22/ZSM-23>ZSM-22/ZSM-23>ZSM-22.Strong acidity may exacerbate the excessive cracking,whereas medium acidity can encourage isomerization by promoting the rearrangement of the framework carbon chain. Although four zeolites show essentially the same medium acidity,ZSM-22/ZSM-23 intergrowth and ZSM-22 display significantly weaker acidity than ZSM-23 and MZSM-22/ZSM-23,in terms of less strong acid sites for the former two zeolite samples.

    Figure 7 29Si MAS NMR spectra of (a)ZSM-22/ZSM-23,(b)ZSM-22,(c)ZSM-23,and (d)MZSM-22/ZSM-23

    Table 3 SiO2/Al2O3 ratios,27Al NMR data and NH3-TPD analysis results of various zeolites

    Figure 9 shows the Py-FTIR spectra of as-prepared zeolites at different desorption temperatures;the absorption peaks at 1545 and 1454 cm?1are attributed to Br?nsted and Lewis acid sites,respectively[42],whereas the adsorption quantities at 150 and 450°C are deemed to the total acidity and strong acidity,respectively.As given in Table 4,most of the Br?nsted acid sites belong to strong acid sites.In particular,the number of Br?nsted acid sites in ZSM-23 far exceeds the number of Lewis acid centers,whereas ZSM-22 has more Lewis acid sites.Compared to MZSM-22/ZSM-23,ZSM-22/ZSM-23 has a higher amount of Br?nsted acid sites.Therefore,ZSM-22/ZSM-23 should be catalytically more active for the hydroisomerization reaction which occurs primarily on the Br?nsted acid sites[43].

    Figure 8 NH3-TPD profiles of (a)ZSM-22/ZSM-23,(b)ZSM-22,(c)ZSM-23,and (d)MZSM-22/ZSM-23

    Figure 9 Py-FTIR spectra of as-prepared zeolites at different desorption temperatures

    Table 4 Acidity distribution of as-synthesized zeolites derived from Py-FTIR

    2.4 Catalytic performance in hydroisomerization

    In general,the hydroisomerization process follows the traditional bifunctional catalytic reaction mechanism[44]:n-alkane is first dehydrogenated at the metal centers to form olefin and olefin is then protonated at the Br?nsted acid sites and successively rearranged to mono-branched and multi-branched carbenium ions,which are further hydrogenated at the metal centers to give the corresponding isomeric products or cracking products.The activity difference of various catalysts was mainly related to the nature of the zeolite supports,because approximately the same active metal loading was used by the same preparation method.

    Figure 10 displays the conversion ofn-hexadecane,product selectivity and yield of isomeric products with the reaction temperature for the hydroisomerization ofn-hexadecane over different catalysts.Obviously, the conversion ofn-hexadecane increases with the increase of reaction temperature(Figure 10(a))[45].As the Br?nsted acid sites are responsible to the protonation reactions and the rearrangement of the framework of carbenium ions,the conversion ofn-hexadecane over of various catalysts follows the same sequence of the amount of Br?nsted acid sites,viz.,Pt/ZSM-23>Pt/ZSM-22/ZSM-23 > Pt/MZSM-22/ZSM-23 > Pt/ZSM-22.Pt/ZSM-22 shows much lowern-hexadecane conversion than other three catalysts,which may also be related to the greater mass transfer resistance due to the larger grains.

    Figure 10 Conversion of n-C16 (a),selectivity to i-C16 (b),and yield of i-C16(c)as a function of temperature over different catalysts

    Meanwhile,as shown in Figure 10(b),various catalysts are rather different in the product selectivity:Pt/ZSM-22 exhibits the highest selectivity to the isomeric products,whereas Pt/ZSM-23 the lowest selectivity;in contrast,Pt/ZSM-22/ZSM-23 and Pt/MZSM-22/ZSM-23 display approximately the same selectivity to isomeric products.It is probably explained by the fact that excessive amounts of strong acid sites are favorable to the hydrocracking side reactions. In practice,an ideal bifunctional catalyst in the hydroisomerization ofn-hexadecane is characterized by the high yield of isomeric hexadecanes, that is, both good conversion and high selectivity.As illustrated in Figure 10(c),the yield of isomeric hexadecanes all increases first and then decreases with increasing temperature.At first,a gradual increase in temperature may promote the hydroisomerization reaction and increase the conversion;however,overly high temperature is also more conducive to the cracking reaction,leading to a decrease in the yield ofi-C16.Although Pt/ZSM-22/ZSM-23 is not the most outstanding catalyst in terms of then-hexadecane conversion or the selectivity to isomeric products,it exhibits the highest yield of isomeric hexadecanes.Owing to the inheritance of both Pt/ZSM-22 and Pt/ZSM-23,Pt/ZSM-22/ZSM-23 shows ann-hexadecane conversion of 58%and a selectivity of 78%to isomeric hexadecanes,resulting in a high yield ofi-C16(45%).

    Table 5 gives the product distribution ofn-hexadecane hydroisomerization over different catalysts at 320°C with a contact time of 1.12 min.The products are abbreviated asn-Cx,i-CxandyM-Cx,wheren-Cxandi-Cxrefer to straight chain alkanes and branched chain alkanes,respectively andxdenoted the number of carbon atoms.The isomer productsyM-Cxmeans that methyl appears at theyposition of isomeric hexadecane. As mentioned above,Pt/ZSM-23 exhibits more hydrocracking products due to its more strong Br?nsted acid sites[46].The high proportion of 7Me-C15(with the branched chain at the center of the chain)in the products over Pt/ZSM-22/ZSM-23 and Pt/MZSM-22/ZSM-23 confirms the“l(fā)ock-key”form selection mechanism.In contrast,the high content of both 7MC15and 2M-C15in the product of Pt/ZSM-22 proves the existence of both “pore mouth”and “key-lock” reaction routes[47].

    Table 5 Product distribution of the n-hexadecane hydroisomerization over different catalysts

    3 Conclusions

    ZSM-22/ZSM-23 intergrowth zeolite was successfully synthesized by hydrothermal method with diethylamine(DEA)and dimethylamine(DMA)as dual structure directing agents at a DMA/DEA molar ratio of 24,from the gel of 1 SiO2∶0.01 Al2O3∶0.72 DMA∶0.03 DEA∶45 H2O∶0.1 NaOH and crystallized at 180°C for 66 h.

    In comparison with ZSM-22 with large grain size,small surface area and insufficient acid quantity and ZSM-23 with excessive strong Br?nsted acid sites,ZSM-22/ZSM-23 intergrowth shows more balanced morphological and acidic properties. After loading 0.5%Pt,the bi-functional Pt/ZSM-22/ZSM-23 catalyst exhibits excellent performance in the hydroisomerization ofn-hexadecane,with a much higher yield ofi-C16products(dominated by mono-branched isomers)than those obtained over Pt supported on ZSM-22 and ZSM-22 and their mechanical mixture.Such a discovery may provide helpful perspectives to the development of efficient bifunctional catalysts for the hydroisomerization of long-chain alkanes.

    69精品国产乱码久久久| 久久久欧美国产精品| 丝袜喷水一区| 国产精品一区二区在线观看99| 久久精品成人免费网站| 久久久久国产一级毛片高清牌| 夜夜夜夜夜久久久久| 曰老女人黄片| 亚洲国产欧美日韩在线播放| 搡老岳熟女国产| 国产亚洲欧美在线一区二区| 国产黄色免费在线视频| 操出白浆在线播放| 国产精品一区二区在线不卡| 一边摸一边抽搐一进一出视频| 亚洲精品在线观看二区| 午夜福利免费观看在线| 香蕉国产在线看| 这个男人来自地球电影免费观看| 国产三级黄色录像| 老司机在亚洲福利影院| 久久久久国产一级毛片高清牌| 日韩有码中文字幕| 亚洲人成电影免费在线| bbb黄色大片| 亚洲熟女精品中文字幕| 制服诱惑二区| 日本av免费视频播放| 欧美日韩视频精品一区| 亚洲国产av影院在线观看| 亚洲人成电影免费在线| 亚洲精品乱久久久久久| 成年女人毛片免费观看观看9 | 美女视频免费永久观看网站| 人妻 亚洲 视频| 精品久久久久久久毛片微露脸| 99香蕉大伊视频| 制服人妻中文乱码| 建设人人有责人人尽责人人享有的| 国产精品麻豆人妻色哟哟久久| 成人亚洲精品一区在线观看| 国产精品秋霞免费鲁丝片| 国产aⅴ精品一区二区三区波| 热99国产精品久久久久久7| 丝瓜视频免费看黄片| 精品人妻熟女毛片av久久网站| 超色免费av| 夫妻午夜视频| 一级黄色大片毛片| 亚洲,欧美精品.| 母亲3免费完整高清在线观看| 日本撒尿小便嘘嘘汇集6| 日日摸夜夜添夜夜添小说| 精品一区二区三区视频在线观看免费 | 亚洲黑人精品在线| 亚洲国产中文字幕在线视频| 成年人午夜在线观看视频| 新久久久久国产一级毛片| 女性生殖器流出的白浆| 捣出白浆h1v1| 丰满饥渴人妻一区二区三| av视频免费观看在线观看| 亚洲精品中文字幕一二三四区 | 国产xxxxx性猛交| 国产精品av久久久久免费| 黄色片一级片一级黄色片| 啦啦啦中文免费视频观看日本| 建设人人有责人人尽责人人享有的| 国产精品国产av在线观看| 最近最新免费中文字幕在线| 91大片在线观看| 国产精品一区二区精品视频观看| 91麻豆精品激情在线观看国产 | 国产免费现黄频在线看| 99久久精品国产亚洲精品| 免费一级毛片在线播放高清视频 | 一区在线观看完整版| 国产aⅴ精品一区二区三区波| 91精品三级在线观看| 女性生殖器流出的白浆| 精品国产一区二区久久| 一本久久精品| 久久狼人影院| 一区在线观看完整版| 看免费av毛片| 午夜免费成人在线视频| 51午夜福利影视在线观看| 女人精品久久久久毛片| 一本大道久久a久久精品| 国产精品影院久久| 亚洲欧美一区二区三区黑人| 丰满人妻熟妇乱又伦精品不卡| 亚洲欧美日韩另类电影网站| www.999成人在线观看| 汤姆久久久久久久影院中文字幕| 国产aⅴ精品一区二区三区波| 久热爱精品视频在线9| 久久精品熟女亚洲av麻豆精品| 天堂中文最新版在线下载| 亚洲精品乱久久久久久| 一级黄色大片毛片| 大香蕉久久网| 在线观看免费午夜福利视频| 91九色精品人成在线观看| 国产精品影院久久| 中文字幕人妻丝袜制服| 成人国产av品久久久| 1024香蕉在线观看| 免费在线观看黄色视频的| 在线观看免费高清a一片| 成人av一区二区三区在线看| 在线永久观看黄色视频| 国产欧美日韩一区二区精品| 在线观看免费高清a一片| 午夜免费成人在线视频| 久久亚洲真实| 一本综合久久免费| 99re在线观看精品视频| 这个男人来自地球电影免费观看| 国产精品电影一区二区三区 | 女人久久www免费人成看片| 18禁黄网站禁片午夜丰满| 色综合婷婷激情| 久久久国产欧美日韩av| 日韩视频一区二区在线观看| 国产男女内射视频| 亚洲三区欧美一区| 91成年电影在线观看| 视频区图区小说| 热re99久久国产66热| www.自偷自拍.com| 天堂中文最新版在线下载| 男女床上黄色一级片免费看| 三级毛片av免费| 色播在线永久视频| 男女无遮挡免费网站观看| av超薄肉色丝袜交足视频| 欧美中文综合在线视频| 亚洲精品国产区一区二| 国产精品av久久久久免费| 久久久久国产一级毛片高清牌| 亚洲一区中文字幕在线| 亚洲av美国av| 精品国产乱码久久久久久小说| 国产成人精品久久二区二区免费| 国产精品99久久99久久久不卡| 国产精品久久久久久精品电影小说| 精品国产一区二区久久| 国产成人精品无人区| 久9热在线精品视频| 中文字幕人妻熟女乱码| 一边摸一边抽搐一进一小说 | 最近最新免费中文字幕在线| 三级毛片av免费| 亚洲欧洲精品一区二区精品久久久| 日日爽夜夜爽网站| 国产在视频线精品| 天堂俺去俺来也www色官网| av线在线观看网站| 亚洲,欧美精品.| 日韩欧美免费精品| 欧美乱妇无乱码| 久久这里只有精品19| 一边摸一边抽搐一进一小说 | 精品熟女少妇八av免费久了| 精品久久久精品久久久| 一进一出好大好爽视频| 免费在线观看黄色视频的| 女人爽到高潮嗷嗷叫在线视频| 国产又色又爽无遮挡免费看| 99精品久久久久人妻精品| 精品高清国产在线一区| 国产精品久久久人人做人人爽| 亚洲熟女精品中文字幕| 老司机亚洲免费影院| 在线永久观看黄色视频| 亚洲伊人久久精品综合| 亚洲精品一卡2卡三卡4卡5卡| 天堂动漫精品| 亚洲精品乱久久久久久| 国产精品久久久久久精品古装| 亚洲中文av在线| 国产一区二区在线观看av| 国产精品国产高清国产av | 亚洲av国产av综合av卡| 男男h啪啪无遮挡| 亚洲精品在线观看二区| 汤姆久久久久久久影院中文字幕| 精品国产国语对白av| av欧美777| tocl精华| 在线十欧美十亚洲十日本专区| 在线永久观看黄色视频| 桃花免费在线播放| 女同久久另类99精品国产91| 午夜福利在线免费观看网站| 久久久久精品国产欧美久久久| 老汉色∧v一级毛片| 国产成人精品在线电影| www.熟女人妻精品国产| 国产深夜福利视频在线观看| 色精品久久人妻99蜜桃| 亚洲国产欧美网| 久久国产精品男人的天堂亚洲| 1024视频免费在线观看| 国产在视频线精品| 亚洲精品美女久久av网站| 两人在一起打扑克的视频| 激情在线观看视频在线高清 | 美女主播在线视频| 亚洲欧美精品综合一区二区三区| 午夜福利免费观看在线| 欧美大码av| 男人舔女人的私密视频| 汤姆久久久久久久影院中文字幕| 国产精品久久久久成人av| 宅男免费午夜| 亚洲精品乱久久久久久| 男人舔女人的私密视频| 黄片大片在线免费观看| 一本大道久久a久久精品| 国产精品免费一区二区三区在线 | 亚洲国产欧美在线一区| 女人被躁到高潮嗷嗷叫费观| 69av精品久久久久久 | 亚洲性夜色夜夜综合| 亚洲国产中文字幕在线视频| 亚洲av成人不卡在线观看播放网| 男女边摸边吃奶| 亚洲 欧美一区二区三区| 国产xxxxx性猛交| 欧美日韩视频精品一区| 777久久人妻少妇嫩草av网站| 黄色视频不卡| 中文字幕最新亚洲高清| 久久国产精品男人的天堂亚洲| 欧美日韩视频精品一区| 又紧又爽又黄一区二区| 日韩欧美免费精品| 91精品国产国语对白视频| 搡老岳熟女国产| 久9热在线精品视频| 岛国在线观看网站| 欧美日韩中文字幕国产精品一区二区三区 | 亚洲午夜理论影院| 人妻 亚洲 视频| 午夜老司机福利片| 日韩一区二区三区影片| 久久精品国产亚洲av高清一级| 国产av国产精品国产| 国产一区有黄有色的免费视频| 欧美亚洲 丝袜 人妻 在线| 王馨瑶露胸无遮挡在线观看| 亚洲,欧美精品.| 久久人妻福利社区极品人妻图片| 久久久精品国产亚洲av高清涩受| 丰满人妻熟妇乱又伦精品不卡| 99久久精品国产亚洲精品| 国产精品影院久久| 国产精品久久久av美女十八| 国产精品国产av在线观看| 亚洲性夜色夜夜综合| 久久久久久久精品吃奶| 精品国产一区二区久久| 淫妇啪啪啪对白视频| 亚洲欧美精品综合一区二区三区| 精品国产一区二区三区四区第35| 黄色视频,在线免费观看| 黄色片一级片一级黄色片| 一级毛片女人18水好多| 999精品在线视频| 国产高清激情床上av| 91av网站免费观看| 精品一区二区三区四区五区乱码| 国产1区2区3区精品| 999精品在线视频| 国产精品免费一区二区三区在线 | 天天影视国产精品| 国产伦理片在线播放av一区| 丝袜美腿诱惑在线| 99香蕉大伊视频| 亚洲精品久久午夜乱码| 天堂俺去俺来也www色官网| 国产精品免费一区二区三区在线 | 国产精品免费一区二区三区在线 | 亚洲中文av在线| 国产一区二区在线观看av| 亚洲色图综合在线观看| 婷婷成人精品国产| 欧美日本中文国产一区发布| 18在线观看网站| 十八禁高潮呻吟视频| 久久天躁狠狠躁夜夜2o2o| 色综合婷婷激情| 国产伦理片在线播放av一区| 国产精品久久电影中文字幕 | 日韩视频在线欧美| 成人国产av品久久久| 大香蕉久久成人网| 国产精品免费视频内射| 日韩欧美免费精品| 黑人操中国人逼视频| 亚洲第一青青草原| 午夜久久久在线观看| 国产深夜福利视频在线观看| av福利片在线| 国产日韩欧美视频二区| 麻豆av在线久日| 不卡av一区二区三区| 啦啦啦 在线观看视频| 欧美精品av麻豆av| 国产精品香港三级国产av潘金莲| 成年女人毛片免费观看观看9 | 啦啦啦免费观看视频1| 日本wwww免费看| 美女视频免费永久观看网站| 亚洲天堂av无毛| 一级a爱视频在线免费观看| 少妇裸体淫交视频免费看高清 | 在线观看免费日韩欧美大片| 免费日韩欧美在线观看| 免费观看av网站的网址| 99国产精品99久久久久| 国产欧美日韩精品亚洲av| 国产亚洲午夜精品一区二区久久| 国产在线观看jvid| 一本色道久久久久久精品综合| 美女视频免费永久观看网站| 欧美成狂野欧美在线观看| 亚洲专区国产一区二区| 69av精品久久久久久 | 国产黄色免费在线视频| 一级a爱视频在线免费观看| 18禁美女被吸乳视频| 成人精品一区二区免费| 亚洲熟妇熟女久久| 91老司机精品| 久久中文看片网| 老司机福利观看| 国产精品影院久久| 国产成人免费观看mmmm| 日韩成人在线观看一区二区三区| 亚洲免费av在线视频| 日韩免费av在线播放| 亚洲熟女精品中文字幕| 欧美日韩黄片免| 汤姆久久久久久久影院中文字幕| 亚洲精品成人av观看孕妇| 亚洲av第一区精品v没综合| 色播在线永久视频| 亚洲av电影在线进入| 看免费av毛片| 99re6热这里在线精品视频| 色综合欧美亚洲国产小说| 丁香六月天网| 极品人妻少妇av视频| 飞空精品影院首页| 美女主播在线视频| 三上悠亚av全集在线观看| 久久性视频一级片| 亚洲熟女毛片儿| 欧美精品人与动牲交sv欧美| 亚洲一区中文字幕在线| 亚洲av欧美aⅴ国产| 岛国在线观看网站| 人成视频在线观看免费观看| 97人妻天天添夜夜摸| 男女之事视频高清在线观看| 精品久久久精品久久久| 欧美激情高清一区二区三区| 男男h啪啪无遮挡| 国产精品九九99| 精品一区二区三区av网在线观看 | 一级片'在线观看视频| 免费看a级黄色片| 人人妻人人澡人人看| 国产欧美日韩一区二区三区在线| 国产精品美女特级片免费视频播放器 | 99精国产麻豆久久婷婷| 精品国产国语对白av| 国产成人精品在线电影| 一区二区三区国产精品乱码| 午夜福利在线免费观看网站| 高清欧美精品videossex| 香蕉丝袜av| 黑人操中国人逼视频| 俄罗斯特黄特色一大片| 精品久久久精品久久久| 高清黄色对白视频在线免费看| 亚洲一区中文字幕在线| 久久精品成人免费网站| 国产无遮挡羞羞视频在线观看| 欧美乱妇无乱码| 美女视频免费永久观看网站| 午夜老司机福利片| 日韩成人在线观看一区二区三区| 2018国产大陆天天弄谢| 久久天堂一区二区三区四区| 精品第一国产精品| 99re6热这里在线精品视频| 一级毛片女人18水好多| 国产成人精品在线电影| 免费在线观看视频国产中文字幕亚洲| 黄频高清免费视频| 777久久人妻少妇嫩草av网站| 麻豆av在线久日| 看免费av毛片| 精品乱码久久久久久99久播| 一级毛片女人18水好多| 老司机影院毛片| 黑人操中国人逼视频| 中文字幕另类日韩欧美亚洲嫩草| 亚洲一区中文字幕在线| 亚洲人成电影观看| 久久久久久人人人人人| 精品久久久久久电影网| 少妇精品久久久久久久| 久久久精品94久久精品| 亚洲av美国av| 热re99久久国产66热| 香蕉丝袜av| 亚洲一区中文字幕在线| 欧美日韩成人在线一区二区| 午夜精品国产一区二区电影| 首页视频小说图片口味搜索| 国产成人系列免费观看| 法律面前人人平等表现在哪些方面| 久久久欧美国产精品| 国产成人av激情在线播放| 亚洲精品国产精品久久久不卡| 精品卡一卡二卡四卡免费| 久久中文字幕人妻熟女| 成年人午夜在线观看视频| 1024视频免费在线观看| 成人av一区二区三区在线看| 菩萨蛮人人尽说江南好唐韦庄| 男女午夜视频在线观看| 法律面前人人平等表现在哪些方面| 久久天堂一区二区三区四区| 日日夜夜操网爽| 视频区欧美日本亚洲| 天天躁日日躁夜夜躁夜夜| 亚洲七黄色美女视频| 水蜜桃什么品种好| 中文字幕精品免费在线观看视频| 80岁老熟妇乱子伦牲交| 女人精品久久久久毛片| 日韩免费av在线播放| 亚洲精品自拍成人| 在线观看66精品国产| 欧美激情高清一区二区三区| 窝窝影院91人妻| 黄片小视频在线播放| 夫妻午夜视频| 精品亚洲成国产av| 美女主播在线视频| 欧美亚洲日本最大视频资源| 日本av免费视频播放| 好男人电影高清在线观看| 三级毛片av免费| 精品卡一卡二卡四卡免费| 午夜福利免费观看在线| 久久久久网色| 久久午夜亚洲精品久久| 男人舔女人的私密视频| 三级毛片av免费| 在线观看一区二区三区激情| 伦理电影免费视频| 久久天堂一区二区三区四区| 在线观看免费高清a一片| 精品免费久久久久久久清纯 | 精品一区二区三区视频在线观看免费 | 一区二区av电影网| 亚洲美女黄片视频| 无人区码免费观看不卡 | 人妻久久中文字幕网| 精品一品国产午夜福利视频| 亚洲avbb在线观看| 久久中文看片网| 日日爽夜夜爽网站| 老司机影院毛片| 手机成人av网站| 深夜精品福利| 亚洲欧美一区二区三区久久| 啪啪无遮挡十八禁网站| 色婷婷久久久亚洲欧美| 成年人黄色毛片网站| www.自偷自拍.com| aaaaa片日本免费| 巨乳人妻的诱惑在线观看| 女人精品久久久久毛片| 激情视频va一区二区三区| av有码第一页| 久久毛片免费看一区二区三区| 亚洲一区二区三区欧美精品| 午夜激情av网站| 天堂中文最新版在线下载| 国产精品电影一区二区三区 | 丰满饥渴人妻一区二区三| 天天添夜夜摸| 啦啦啦中文免费视频观看日本| 国产淫语在线视频| 欧美黄色淫秽网站| 一边摸一边做爽爽视频免费| 中亚洲国语对白在线视频| 国产精品熟女久久久久浪| 国产精品九九99| av国产精品久久久久影院| 久久狼人影院| 色综合欧美亚洲国产小说| 国产欧美日韩一区二区三区在线| 99精品久久久久人妻精品| 国产一区二区三区视频了| 欧美在线一区亚洲| 一本大道久久a久久精品| 成年人免费黄色播放视频| 国产精品电影一区二区三区 | 亚洲专区中文字幕在线| 中亚洲国语对白在线视频| 一本大道久久a久久精品| 99精国产麻豆久久婷婷| 中文字幕最新亚洲高清| 99精品欧美一区二区三区四区| 亚洲成人手机| 黑丝袜美女国产一区| 在线观看66精品国产| 热99re8久久精品国产| 日韩欧美国产一区二区入口| 老司机福利观看| a级片在线免费高清观看视频| 热99re8久久精品国产| 亚洲专区中文字幕在线| 三级毛片av免费| 国产亚洲精品一区二区www | 黄片小视频在线播放| 一区在线观看完整版| 丰满饥渴人妻一区二区三| 亚洲黑人精品在线| 一边摸一边抽搐一进一出视频| 亚洲精品中文字幕一二三四区 | 欧美激情 高清一区二区三区| 精品午夜福利视频在线观看一区 | 久久久欧美国产精品| 欧美国产精品一级二级三级| 丝袜喷水一区| 精品午夜福利视频在线观看一区 | 亚洲欧美日韩高清在线视频 | 欧美另类亚洲清纯唯美| 捣出白浆h1v1| av国产精品久久久久影院| 男女下面插进去视频免费观看| 欧美亚洲日本最大视频资源| 亚洲人成电影免费在线| 国产淫语在线视频| 精品高清国产在线一区| 久久精品91无色码中文字幕| 在线观看www视频免费| 首页视频小说图片口味搜索| 99re6热这里在线精品视频| 久久国产亚洲av麻豆专区| 亚洲国产欧美一区二区综合| 国产精品影院久久| 女人精品久久久久毛片| 欧美黄色片欧美黄色片| 两性午夜刺激爽爽歪歪视频在线观看 | 亚洲成人免费电影在线观看| tocl精华| 国产精品香港三级国产av潘金莲| 少妇猛男粗大的猛烈进出视频| 精品免费久久久久久久清纯 | 丝袜在线中文字幕| 十八禁人妻一区二区| 丝袜在线中文字幕| 欧美中文综合在线视频| 午夜福利在线免费观看网站| 日韩中文字幕欧美一区二区| 久久香蕉激情| 午夜福利一区二区在线看| 午夜91福利影院| 超色免费av| 丝瓜视频免费看黄片| 成人18禁高潮啪啪吃奶动态图| 免费女性裸体啪啪无遮挡网站| 午夜激情av网站| 色婷婷av一区二区三区视频| 99精品欧美一区二区三区四区| 一级毛片精品| 久久久久久久久久久久大奶| 精品人妻1区二区| 精品国产乱码久久久久久小说| 国产免费av片在线观看野外av| 免费一级毛片在线播放高清视频 | 精品国产乱子伦一区二区三区| 男女免费视频国产| 国产高清视频在线播放一区| 日本vs欧美在线观看视频| 欧美老熟妇乱子伦牲交| 色婷婷久久久亚洲欧美| 国产色视频综合| 亚洲第一av免费看| 国产av国产精品国产| 男女之事视频高清在线观看| 午夜精品国产一区二区电影| av天堂久久9| 欧美黄色片欧美黄色片| 亚洲专区字幕在线| 欧美亚洲 丝袜 人妻 在线| 另类精品久久| av福利片在线| 国产精品99久久99久久久不卡| 水蜜桃什么品种好| 精品乱码久久久久久99久播| 日日摸夜夜添夜夜添小说| 怎么达到女性高潮| 91精品三级在线观看|