DOI: 10.57760/sciencedb.23042
title: A dataset for protozeolite seed-assisted construction of hierarchical nano-ZSM-5 zeolites and their catalytic application in Meinwald rearrangement
title: A dataset for protozeolite seed-assisted construction of hierarchical nano-ZSM-5 zeolites and their catalytic application in Meinwald rearrangement

description: First of all, protozeolite seeds were hydrothermally synthesized with the molar ratio of 1SiO2: 0.35TPAOH: 5H2O. Typically, TEOS and deionized water were mixed at room temperature till complete hydrolysis, followed by addition of TPAOH under fast stirring. Then, the gel was transferred into a Tefon-lined stainless steel autoclave conducted at 90 oC for 24 h under static conditions. The as-prepared solid sample was centrifuged, washed with deionized water, vacuum dried at 80 oC for 12 h, and then used as the seeds for the SA-DGC method.Then, nano-ZSM-5 zeolites were synthesized by SA-DGC method with the molar ratio of 1SiO2: 0.01Al2O3: 0.25NaOH: 25H2O. Typically, silicasol (30 wt% SiO2) and deionized water were mixted at room temperature, followed by addition of NaAlO2 and NaOH under stirring until a homogenous mixture was obtained. Then, different amounts of protozeolite seeds were added into the above mixture and stirred until homogeneity. Subsequently, the mixture was vacuum dried at 80 oC for 12 h and then placed in a Teflon cup which was placed into another larger autoclave and different amounts of water was added outside the cup to create the steam for the crystallization conditions. The autoclave was placed in an oven kept at 150 oC for continuous crystallization. After cooling down to the room temperature, the solid were collected and then dried at 110 oC for 4 h, calcined at 500 oC for 2 h. The resulting samples were denoted as SA-DGC-x-y-z, where x represents the ratio of SiO2/TPA+ calculated according to the amounts of seeds added, y represents the volume (mL) of water added into the autoclave, z represents the crystallization time (h).For comparison, the conventional ZSM-5 zeolites were prepared by dry-gel conversion (DGC) method according to the above procedures by replacing of seeds with TPAOH. The resulting samples were named as DGC-x-y-z, where x, y, z have the same meaning as above.Before the catalytic test, all the samples were subjected to ion-exchange with 1 M NH4NO3 solution at room temperature for 24 h, followed by drying at 110 oC for 4 h and calcining at 500 oC for 2 h.The structure and crystallinity of samples were investigated via power X-ray diffraction (XRD) on a Bruker D8 Advance diffractometer with Cu kα radiation (λ = 0.1541 nm) at a scanning rate of 5 o/min from 5o to 50o, and the relative crystallinity (RC) of samples was calculated from the areas of main peaks between 2θ = 8-10°. The framework vibration bands of samples were measured through Fourier Transform Infrared Spectroscopy (FT-IR) on a Nicolet 380 spectrometer using the KBr pellet tehnique. The morphologies of samples were observed using scanning electron microscope (SEM, FlexSEM-1000, Hitachi), field emission scanning electron microscope (FESEM, SU8010, Hitachi) and transmission electron microscopy (TEM, JEM-2100F, JEOL). X-ray fluorescence (XRF) was used to measure the SiO2/Al2O3 rations of samples on a Bruker S4 pioneer X-ray fluorescence spectrometer. N2 adsorption-desorption isotherms were obtained at -196 oC on a Quantachrome Autosorb-1 instrument. The total surface area (Stotal) and pore volume (Vtotal) were calculated by the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) models, respectively. The micropore surface area (Smicro) and volume (Vmicro) were calculated by the t model. The external surface area (Sexter) and mesoporous volume (Vmeso) were obtained by subtracting Smicro and Vmicro from Stotal and Vtotal, respectively. 27Al magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectra were recorded using a Varian Infinity-Plus 300 MHz spectrometer with resonance frequencies of 78.13 MHz. Al(NO3)3 was used as the reference for the 27Al chemical shift.The acidity of samples was investigated by Temperature programmed desorption of ammonia (NH3-TPD) and FTIR spectra of adsorbed pyridine (Py-FTIR). NH3-TPD was performed in a quartz U-tube reactor equipped with a thermal conductivity detector (TCD). At a N2 flow of 50 mL/min, the sample (0.1 g, 20-30 mush) was pretreated at 500 oC for 2 h. After cooling down to 50 oC, NH3 was supplied to the sample until saturation adsorption. Then, the reactor was maintained at 150 oC for 1 h to remove physically adsorbed NH3. Finally, the sample was heated from 150 to 550 oC at a rate of 15 oC/min.Py-FTIR was analyzed on a Nicolet 380 spectrometer. All samples were pressed into self-supporting wafers (diameter:13 mm, weight: 15 mg) and then pre-treated at 500 oC for 4 h under vacuum (10-3 Pa). Adsorption of pyridine was preceded in situ at room temperature and then evacuated at 200 oC for 2 h. Afterwards, the difference spectrum were obtained by subtracting the spectrum of the sample before probe adsorption.Figure 1. (a) XRD patterns of protozeolite seeds, (b) FT-IR spectra of protozeolite seeds synthesized at 90 oC for different time, (c) SEM and (d) TEM images of protozeolite seeds.Figure 2. XRD patterns of samples synthesized by the SA-DGC and DGC methods. Figure 3. FT-IR spectra of samples synthesized by the SA-DGC and DGC methods. Figure 4. SEM images of samples synthesized by the SA-DGC and DGC methods. Figure 5. (a) N2 adsorption-desorption isotherms and BJH mesopore size distribution, (b) 27Al MAS NMR spectra, (c) NH3-TPD curves and (d) FT-IR spectra of adsorbed pyridine.
description: First of all, protozeolite seeds were hydrothermally synthesized with the molar ratio of 1SiO2: 0.35TPAOH: 5H2O. Typically, TEOS and deionized water were mixed at room temperature till complete hydrolysis, followed by addition of TPAOH under fast stirring. Then, the gel was transferred into a Tefon-lined stainless steel autoclave conducted at 90 oC for 24 h under static conditions. The as-prepared solid sample was centrifuged, washed with deionized water, vacuum dried at 80 oC for 12 h, and then used as the seeds for the SA-DGC method.Then, nano-ZSM-5 zeolites were synthesized by SA-DGC method with the molar ratio of 1SiO2: 0.01Al2O3: 0.25NaOH: 25H2O. Typically, silicasol (30 wt% SiO2) and deionized water were mixted at room temperature, followed by addition of NaAlO2 and NaOH under stirring until a homogenous mixture was obtained. Then, different amounts of protozeolite seeds were added into the above mixture and stirred until homogeneity. Subsequently, the mixture was vacuum dried at 80 oC for 12 h and then placed in a Teflon cup which was placed into another larger autoclave and different amounts of water was added outside the cup to create the steam for the crystallization conditions. The autoclave was placed in an oven kept at 150 oC for continuous crystallization. After cooling down to the room temperature, the solid were collected and then dried at 110 oC for 4 h, calcined at 500 oC for 2 h. The resulting samples were denoted as SA-DGC-x-y-z, where x represents the ratio of SiO2/TPA+ calculated according to the amounts of seeds added, y represents the volume (mL) of water added into the autoclave, z represents the crystallization time (h).For comparison, the conventional ZSM-5 zeolites were prepared by dry-gel conversion (DGC) method according to the above procedures by replacing of seeds with TPAOH. The resulting samples were named as DGC-x-y-z, where x, y, z have the same meaning as above.Before the catalytic test, all the samples were subjected to ion-exchange with 1 M NH4NO3 solution at room temperature for 24 h, followed by drying at 110 oC for 4 h and calcining at 500 oC for 2 h.The structure and crystallinity of samples were investigated via power X-ray diffraction (XRD) on a Bruker D8 Advance diffractometer with Cu kα radiation (λ = 0.1541 nm) at a scanning rate of 5 o/min from 5o to 50o, and the relative crystallinity (RC) of samples was calculated from the areas of main peaks between 2θ = 8-10°. The framework vibration bands of samples were measured through Fourier Transform Infrared Spectroscopy (FT-IR) on a Nicolet 380 spectrometer using the KBr pellet tehnique. The morphologies of samples were observed using scanning electron microscope (SEM, FlexSEM-1000, Hitachi), field emission scanning electron microscope (FESEM, SU8010, Hitachi) and transmission electron microscopy (TEM, JEM-2100F, JEOL). X-ray fluorescence (XRF) was used to measure the SiO2/Al2O3 rations of samples on a Bruker S4 pioneer X-ray fluorescence spectrometer. N2 adsorption-desorption isotherms were obtained at -196 oC on a Quantachrome Autosorb-1 instrument. The total surface area (Stotal) and pore volume (Vtotal) were calculated by the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) models, respectively. The micropore surface area (Smicro) and volume (Vmicro) were calculated by the t model. The external surface area (Sexter) and mesoporous volume (Vmeso) were obtained by subtracting Smicro and Vmicro from Stotal and Vtotal, respectively. 27Al magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectra were recorded using a Varian Infinity-Plus 300 MHz spectrometer with resonance frequencies of 78.13 MHz. Al(NO3)3 was used as the reference for the 27Al chemical shift.The acidity of samples was investigated by Temperature programmed desorption of ammonia (NH3-TPD) and FTIR spectra of adsorbed pyridine (Py-FTIR). NH3-TPD was performed in a quartz U-tube reactor equipped with a thermal conductivity detector (TCD). At a N2 flow of 50 mL/min, the sample (0.1 g, 20-30 mush) was pretreated at 500 oC for 2 h. After cooling down to 50 oC, NH3 was supplied to the sample until saturation adsorption. Then, the reactor was maintained at 150 oC for 1 h to remove physically adsorbed NH3. Finally, the sample was heated from 150 to 550 oC at a rate of 15 oC/min.Py-FTIR was analyzed on a Nicolet 380 spectrometer. All samples were pressed into self-supporting wafers (diameter:13 mm, weight: 15 mg) and then pre-treated at 500 oC for 4 h under vacuum (10-3 Pa). Adsorption of pyridine was preceded in situ at room temperature and then evacuated at 200 oC for 2 h. Afterwards, the difference spectrum were obtained by subtracting the spectrum of the sample before probe adsorption.Figure 1. (a) XRD patterns of protozeolite seeds, (b) FT-IR spectra of protozeolite seeds synthesized at 90 oC for different time, (c) SEM and (d) TEM images of protozeolite seeds.Figure 2. XRD patterns of samples synthesized by the SA-DGC and DGC methods. Figure 3. FT-IR spectra of samples synthesized by the SA-DGC and DGC methods. Figure 4. SEM images of samples synthesized by the SA-DGC and DGC methods. Figure 5. (a) N2 adsorption-desorption isotherms and BJH mesopore size distribution, (b) 27Al MAS NMR spectra, (c) NH3-TPD curves and (d) FT-IR spectra of adsorbed pyridine.