Stabilization effect of phosphorus on steamed H-MFI zeolites

Caeiro, G.; Magnoux, P.; Lopes, J.M.; Ribeiro, F. Ramôa; Menezes, Sônia Maria Cabral de; Costa, A.F.; Cerqueira, Henrique S.

doi:10.1016/j.apcata.2006.08.016

Cited by 131 publications

(150 citation statements)

References 55 publications

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“…% of P reduced the total acid site density by approximately 64 %, while for 3.2PHZSM-5 the reduction was around 80% as compared to HZSM-5 (see Table 2). These results are similar to those of Caeiro et al (2006) and Lu and Liu (2011). Hodala et al (2014) verified by TPD-NH3 that stronger acid sites were replaced with weaker ones after phosphate modification.…”

Section: Catalyst Characterizationsupporting

confidence: 79%

Synthesis of Propylene From Ethanol Using Phosphorus-Modified HZSM-5

Costa

Silva

2016

Braz. J. Chem. Eng.

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-Effects of phosphorus addition to HZSM-5 on ethanol conversion to propylene were evaluated. Catalysts were characterized by XRF, XRD, nitrogen adsorption, 27Al and 31 P MAS NMR, n-propylamine and ammonia TPD. Increasing P content decreased the strength and density of acid total sites. Ethanol dehydration was carried out in a fixed bed reactor operating at atmospheric pressure. Conversion was around 100% for all catalysts. 1.2 wt% of P catalyst showed the highest propylene yield, and was used to evaluate temperature and ethanol partial pressure effects on the product distribution. The highest propylene accumulated productivity was obtained for an ethanol partial pressure of 0.4 atm. Propylene formation was favored in the temperature range 475-500 °C. Significant changes in the product distribution as a function of time on stream were observed at higher temperatures, suggesting stronger catalyst deactivation. The ethylene yield decreased up to 500 °C, rising significantly at 550 °C, possibly due to heavier product cracking reactions.

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Section: Catalyst Characterizationsupporting

confidence: 79%

Synthesis of Propylene From Ethanol Using Phosphorus-Modified HZSM-5

Costa

Silva

2016

Braz. J. Chem. Eng.

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“…9a and c which is in accordance to literature. 7,12,14,17,18 STXM data presented in Fig. 8 reveal both inter-, and intraparticle heterogeneities in the distribution of phosphorus.…”

Section: Effect Of Thermal Treatment On Phosphated Samplesmentioning

confidence: 89%

“…[6][7][8][9][10][11][12] Even though there is still some debate on the effect of acid site strength on the MTO product distribution, the promoting effect of phosphorus on the hydrothermal stability of H-ZSM-5 is undisputed. 4,9,[13][14][15][16][17][18][19][20][21][22][23][24][25] Zeolite H-ZSM-5 catalysts that contain phosphorus are more stable under hydrothermal conditions i.e. they retain more framework aluminium species and strong acid sites than their non-phosphated counterparts.…”

Section: Introductionmentioning

confidence: 99%

“…in 27 Al MAS NMR and especially 31 P MAS NMR. 14,17,18,42 Another complicating factor is the synthesis conditions used during phosphatation, which vary for different studies. There are three parameters that can affect the structure of the zeolite material, namely (i) acidity coming from the acidic precursor H 3 PO 4 , which is often used, (ii) thermal treatment that is customarily performed after phosphorus introduction, and (iii) the actual presence of phosphorus species.…”

Section: Introductionmentioning

confidence: 99%

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Local silico-aluminophosphate interfaces within phosphated H-ZSM-5 zeolites

Bij

Weckhuysen

2014

Phys. Chem. Chem. Phys.

127

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In order to elucidate phosphorus-zeolite H-ZSM-5 interactions, a variety of phosphorus-modified zeolite H-ZSM-5 materials were studied in a multi-spectroscopic manner. By deploying single pulse 27 Al, 31 P MAS NMR, 2D heteronuclear 27 Al-31 P correlation (HETCOR), 27 Al MQ MAS NMR spectroscopy, TPD of pyridine monitored by FT-IR spectroscopy, and Scanning Transmission X-ray Microscopy (STXM) the interplay and influence of acidity, thermal treatment and phosphorus on the structure and acidity of H-ZSM-5 were established. It was found that while acid treatment did not affect the zeolite structure, thermal treatment leads to the breaking of Si-OH-Al bonds, a decrease in the strong acid site number and the formation of terminal Al-OH groups. No extra-framework aluminium species was observed. Phosphorus precursors interact with the zeolitic framework through hydrogen bonds and physical coordination, as phosphorus species can be simply washed out with hot water. After phosphatation and thermal treatment two effects occur simultaneously, namely (i) phosphorus species transform into water insoluble condensed poly-phosphoric acid and (ii) phosphoric acid binds irreversibly to the terminal Al-OH groups of partially dislodged four-coordinated framework aluminium, forming local silico-aluminophosphate interfaces.These interfaces are potentially the promoters of hydrothermal stability in phosphated zeolite H-ZSM-5.

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“…This means that the phosphorus species formed in the treatment reinforce the zeolite structure and prevent de-alumination. The optimal phosphorus content (highest activity) obtained depends essentially on the zeolite (Si/Al) ratio and on the model reaction used [16,21]. For example, Blasco et al found a maximum in the n-decane cracking activity for P/Al molar ratios of 0.5-0.7 [16].…”

Section: Hydrothermal Stability Of Zsm-5mentioning

confidence: 99%

Maximizing propylene production via FCC technology

2015

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This review looks at the main processes available for the production of light olefins with a focus on maximizing the production of propylene. Maximization of propylene production has become the focus of most refineries because it is in high demand and there is a supply shortage from modern steam crackers, which now produce relatively less propylene. The flexibility of the fluid catalytic cracking (FCC) to various reaction conditions makes it possible as one of the means to close the gap between supply and demand. The appropriate modification of the FCC process is accomplished by the synergistic integration of the catalyst, temperature, reaction-residence time, coke make, and hydrocarbon partial pressure. The main constraints for maximum propylene yield are based on having a suitable catalyst, suitable reactor configuration and reaction conditions.

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Stabilization effect of phosphorus on steamed H-MFI zeolites

Cited by 131 publications

References 55 publications

Synthesis of Propylene From Ethanol Using Phosphorus-Modified HZSM-5

Synthesis of Propylene From Ethanol Using Phosphorus-Modified HZSM-5

Local silico-aluminophosphate interfaces within phosphated H-ZSM-5 zeolites

Maximizing propylene production via FCC technology

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