Hierarchical SAPO-34/18 zeolite with low acid site density for converting methanol to olefins

The Brønsted acid site densities of ZSM-5, BEA and single unit cell self-pillared pentasil (SPP) zeolites of varying Si/Al ratios were measured using a new technique, reactive gas chromatography (RGC), which utilizes alkylamine decomposition to selectively count Brønsted acid sites.

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Selective staining of Brønsted acidity in zeolite ZSM-5-based catalyst extrudates using thiophene as a probe

Physical Chemistry Chemical Physics ◽

10.1039/c4cp03649b ◽

2014 ◽

Vol 16 (39) ◽

pp. 21531-21542 ◽

Cited By ~ 14

Author(s):

Gareth T. Whiting ◽

Florian Meirer ◽

Diego Valencia ◽

Machteld M. Mertens ◽

Anton-Jan Bons ◽

...

Keyword(s):

Acid Site ◽

Reaction Pathway ◽

Bronsted Acid ◽

Brønsted Acidity ◽

Selective Staining ◽

Brönsted Acidity ◽

Site Density ◽

Bronsted Acid Site ◽

Brønsted Acid Site ◽

Brönsted Acid

Brønsted acid site density dictates the reaction pathway in ZSM-5-based extrudates during thiophene oligomerization, visualized non-invasively in 3D using micro-spectroscopy.

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Influence of organic acid site density on pH modeling of Swedish lakes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f99-097 ◽

1999 ◽

Vol 56 (8) ◽

pp. 1461-1470 ◽

Cited By ~ 22

Author(s):

Stephan Köhler ◽

Jakub Hruška ◽

Kevin Bishop

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Total Organic Carbon ◽

Natural Organic Matter ◽

Acid Site ◽

Organic Anion ◽

Charge Balance ◽

Mean Error ◽

Site Density ◽

Median Error

A semidirect titration method was used to determine individual site densities of carboxylic acids present in natural organic matter originating from 74 Swedish lakes. The average carboxylic acid site density of natural organic matter of the studied lakes was 8.6 ± 1.6 µequiv.·mg total organic carbon-1, which is more variable than the site densities observed earlier in a set of streams. These data were then used to assess the effect on modeling pH and organic anion charge contribution caused by the natural variability in site density. Air-equilibrated pH was modeled with a median error of 0.08 pH unit, equivalent to a mean error in the charge balance of 9 µmol·L-1, using measured Cb-Ca and individually determined site densities. A better prediction of pH, however, was made using this average site density and the CBALK approach, which is a different method for estimating total buffering capacity. The mean error in pH prediction was decreased to 0.05 pH unit, equivalent to a mean error in the charge balance of 5 µmol·L-1. These uncertainties in pH prediction are significantly smaller than reported in other studies. This implies that the existing natural variation in site density does not lead to significant effects on modeling pH or anion charge contribution in surface waters in the pH range of 4.5-8.5. Filtered samples (0.45 µm) did not show any significant change in pH, total organic carbon, or site density compared with unfiltered samples.

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High activity, templated mesoporous SO4/ZrO2/HMS catalysts with controlled acid site density for α-pinene isomerisation

Microporous and Mesoporous Materials ◽

10.1016/j.micromeso.2005.01.007 ◽

2005 ◽

Vol 80 (1-3) ◽

pp. 301-310 ◽

Cited By ~ 34

Author(s):

Muriel A. Ecormier ◽

Adam F. Lee ◽

Karen Wilson

Keyword(s):

High Activity ◽

Acid Site ◽

Site Density

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Isomerization ofn-Butane over H-Mordenites under Nitrogen and Hydrogen: Influence of the Acid Site Density

Journal of Catalysis ◽

10.1006/jcat.1998.1967 ◽

1998 ◽

Vol 174 (2) ◽

pp. 185-190 ◽

Cited By ~ 31

Author(s):

M.-Trung Tran ◽

N.S. Gnep ◽

G. Szabo ◽

M. Guisnet

Keyword(s):

Acid Site ◽

Site Density

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Ru-Promoted Ni/Al2O3 Fluidized Catalyst for Biomass Gasification

Catalysts ◽

10.3390/catal10030316 ◽

2020 ◽

Vol 10 (3) ◽

pp. 316 ◽

Cited By ~ 1

Author(s):

Alan Rubén Calzada Hernandez ◽

Daniel Gibran González Castañeda ◽

Adriana Sánchez Enriquez ◽

Hugo de Lasa ◽

Benito Serrano Rosales

Keyword(s):

Acid Site ◽

Biomass Gasification ◽

Temperature Programmed Desorption ◽

Steam Gasification ◽

Bet Surface Area ◽

Temperature Programmed Reduction ◽

N2 Adsorption ◽

Site Density ◽

Temperature Programmed ◽

Adsorption Desorption

Fluidizable catalysts based on Ni/Al2O3 with added Ru were used for the gasification of a lignin surrogate (2-methoxy-4-methylphenol) in a fluidized CREC Riser Simulator reactor. This was done in order to quantify lignin surrogate conversion and lignin surrogate products (H2, CO, CO2 and CH4) as well as the coke deposited on the catalyst. The catalysts that were evaluated contained 5% wt. Ni with various Ru loadings (0.25%, 0.5% and 1% wt). These catalysts were synthesized using an incipient Ni and Ru co-impregnation. Catalysts were characterized using XRD, N2 adsorption-desorption (BET Surface Area, BJH), Temperature Programmed Reduction (TPR), Temperature Programmed Desorption (TPD) and H2 chemisorption. Catalytic steam gasification took place at 550, 600 and 650 °C using 0.5, 1.0 and 1.5, steam/biomass ratios. The results obtained showed that Ru addition helped to decrease both nickel crystallite site sizes and catalyst acid site density. Moreover, it was observed that coke on the catalyst was reduced by 60%. This was the case when compared to the runs with the Ni/Al2O3 free of Ru.

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