Synthesis of Al-rich ZSM-12 using TEAOH as template

Gopal, Srikant; Yoo, Kyesang; Smirniotis, Panagiotis G.

doi:10.1016/s1387-1811(01)00412-7

Cited by 71 publications

(34 citation statements)

References 9 publications

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“…The composition data indicate that the Si/Al ratio of the solid obtained after crystallization is lower than that in the synthesis gel. Gopal et al (2001) found similar results in the synthesis of ZSM-12 zeolite with tetraethylammonium as template. He attributed this phenomenon to inefficiency in the crystallization process.…”

Section: Resultssupporting

confidence: 71%

“…Gopal et al (2001) studied the thermal decomposition of a series of ZSM-12 samples synthesized using TEA as template. They had attributed the mass loss in the temperature range from 430 to 550 • C to decomposition of charge compensating TEA cations.…”

Section: Resultsmentioning

confidence: 99%

“…Reviewing the literature data on the synthesis of ZSM-12, Jacobs and Martens (1987) identified that the lowest Si/Al ratio in which ZSM-12 can be crystallized, as a pure phase, is approximately 40 when monomeric molecules of quaternary ammonium cations are used as templating additive. However a recent work of Gopal et al (2001), using TEAOH as the template, crystallized a pure ZSM-12 phase with Si/Al ratio of 31.…”

Section: Introductionmentioning

confidence: 99%

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Crystallization of ZSM-12 Zeolite with Different Si/Al Ratio

et al. 2005

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In this work the acid properties of a series of HZSM-12 zeolites with different Si/Al ratio were studied. The ZSM-12 crystals were synthesized by the hydrothermal method starting from a gel with the following molar composition: 20MTEA:10Na 2 O:x Al 2 O 3 :100SiO 2 :2000H 2 O, with x = 0.50, 0.67, 1, 1.25 and 2, respectively. The gels were crystallized at 140 • C for 6 days, then washed, dried and calcined to remove the MTEA template. The samples were ion-exchanged with an ammonium chloride solution and calcined again to obtain the zeolites in the acid form. The materials thus obtained were characterized by XRD, SEM, BET, TG and n-butylamine adsorption. The Si/Al ratio in the reaction mixture affects the amount of zeolite produced and the size of the particles. The XRD analysis indicated that the ZSM-12 zeolite crystallizes in a pure form only with Si/Al ratio above 33. The SEM analysis showed the presence of crystallites with very well defined prismatic shapes. The removal of the MTEA of the pores of the ZSM-12 by TG indicated that there are two kinds of internal sites occupied by MTEA inside the structure. The BET area of the ZSM-12 decreases proportionally with the crystallinity of materials. The desorption of n-butylamine showed that the acid site density is proportional to aluminum content, but the Si/Al ratio shows little influence on the relative strengths of these sites.

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Section: Resultssupporting

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crystallization of ZSM-12 Zeolite with Different Si/Al Ratio

et al. 2005

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“…Each run was performed with a time of 7.33 minutes. Figure 1a shows a diffractogram of newly crystallized ZSM-12 zeolites, with different MTEACl/SiO 2 ratios, where the peaks show the formation of the ZSM-12 crystalline phase, similar to those published in the literature 8,9 , indicating also that no other phase was found. Among the characterized supports, the one which showed a higher crystallinity was Y6 non-calcined sample, indicating that the optimum MTEACl/SiO 2 ratio was 1:10, followed by sample X6 non-calcined (MTEACl/SiO 2 = 1:5), and W6 non-calcined sample (MTEACl/SiO 2 = 1:20).…”

Section: Methodssupporting

confidence: 72%

“…Table 2 shows the crystallinity and crystallite sizes for calcined X6, Y6 and W6 samples, and TiO 2 /ZSM-12 at 5, 10 and 15% of titanium. For the ZSM-12 samples, it was observed that the higher crystallinity is represented by the sample Y6, which has the most intense and characteristic peaks of zeolite ZSM-12 9 , influenced by the MTEACl/SiO 2 ratio and the thermal treatment occurred on calcination at 550 ºC. Among the TiO 2 /ZSM-12 samples, the most crystalline was the TiO 2 /ZSM-12 with 5% titanium, which may be due to greater retention of crystallinity of the support ZSM-12, with the TiO 2 competitive phase.…”

Section: Methodsmentioning

confidence: 99%

Oxidative desulfurization of thiophene on TiO2/ZSM-12 zeolite

2016

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In this work the hydrothermal synthesis of ZSM-12 zeolite was performed, varying the MTEACl/SiO 2 ratio, where the synthesis temperature was 140 ºC and the crystallization time was 144 hours. The catalysts were characterized by XRD, FTIR and TG. TiO 2 /ZSM-12 catalysts were used with titanium ions concentrations of 5, 10 and 15%. The oxidative desulfurization (ODS) reactions were performed using a model mixture containing n-heptane as solvent and thiophene as sulfur compound, H 2 O 2 as an oxidizing agent, and acetonitrile as an extractor solvent at reaction temperatures of 30, 50 and 70 ºC. The obtained results shows that TiO 2 /ZSM-12 with 15% of Ti catalyst has a better performance in the ODS reaction converting thiophene at about 60%.

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Effect of temperature Ramp on hydrocarbon desorption profiles from zeolite ZSM‐12

et al. 2016

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Zeolite ZSM-12 with different Si:Al molar ratios and one-dimensional channels with 12 oxygen ring apertures (12R) was synthesized and characterized by different techniques such as: X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller surface area (BET), elemental analysis by atomic absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) of adsorbed pyridine, and NH 3 temperature-programmed desorption (TPD). The synthesized samples were tested as hydrocarbon (HC) trap adsorbents using toluene and ethylene as heavy and light probe molecules for HCs in the exhaust stream at engine cold-start. High heating rate desorption experiments were performed using the Phytronix Laser Diode Thermal Desorption system (S-960 LDTD) coupled with an Atmospheric Pressure Chemical Ionization (APCI) chamber (Phytronix Technologies, Canada) after adsorption of toluene-ethylene mixtures. Three heating rates, which reflect the actual heating rates of the catalytic muffler, were used for the desorption process: 3 8C/s, 5 8C/s, and 9 8C/s. For all solids considered in this study, the two HCs desorbed above 240 8C, which is the light-off temperature of the three-way catalyst. Ag-ZSM-12 with different Si:Al ratios was found the most appropriate HC trapping adsorbent in spite of its slightly lower adsorption capacity. A high desorption temperature for ethylene and toluene was associated with the large density of strong Lewis acid sites in this solid.

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Synthesis of Al-rich ZSM-12 using TEAOH as template

Cited by 71 publications

References 9 publications

Crystallization of ZSM-12 Zeolite with Different Si/Al Ratio

Crystallization of ZSM-12 Zeolite with Different Si/Al Ratio

Oxidative desulfurization of thiophene on TiO2/ZSM-12 zeolite

Effect of temperature Ramp on hydrocarbon desorption profiles from zeolite ZSM‐12

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