Acid Strength of Heteropolyacids and Its Correlation with Catalytic Activity

1994 ◽  
Vol 67 (4) ◽  
pp. 1186-1188 ◽  
Author(s):  
Toshio Okuhara ◽  
Changwen Hu ◽  
Masato Hashimoto ◽  
Makoto Misono
Keyword(s):  
Catalytic Activity ◽  
Acid Strength

Preparation of Strong Acid Catalysts by Sulfate Treatment of Calcined Boehmite

1992 ◽  
Vol 57 (11) ◽  
pp. 2241-2247 ◽  
Author(s):  
Tomáš Hochmann ◽  
Karel Setínek
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Aluminum Sulfate ◽  
Solid Acid ◽  
Strong Acid ◽  
Acid Strength ◽  
Solid Acid Catalysts ◽  
Acid Catalysts ◽  
Preparation Methods ◽  
Indicator Method

Solid acid catalysts with acid strength of -14.52 < H0 < -8.2 were prepared by sulfate treatment of the samples of boehmite calcined at 105-800 °C. Two preparation methods were used: impregnation of the calcined boehmite with 3.5 M H2SO4 or mixing of the boehmite samples with anhydrous aluminum sulfate, in both cases followed by calcination in nitrogen at 650 °C. The catalysts were characterized by measurements of surface area, adsorption of pyridine and benzene, acid strength measurements by the indicator method and by catalytic activity tests in the isomerization of cyclohexene, p-xylene and n-hexane. Properties of the catalysts prepared by both methods were comparable.

scholarly journals THE ENHANCEMENT OF ACID STRENGTH AND CATALYTIC ACTIVITY OF SnO2BY THE ADDITION OF SULFATE ION

1983 ◽  
Vol 12 (3) ◽  
pp. 277-280 ◽  
Author(s):  
Gong-Wei Wang ◽  
Hideshi Hattori ◽  
Kozo Tanabe
Keyword(s):  
Catalytic Activity ◽  
Acid Strength ◽  
Sulfate Ion

Glycolysis of Polyethylene Terephthalate Catalyzed by Solid Superacid

2011 ◽  
Vol 233-235 ◽  
pp. 512-518
Author(s):  
Min Li Zhu ◽  
Yan Qing Liu ◽  
Rui Yi Yan ◽  
Hui Wang ◽  
Zeng Xi Li ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Surface Acidity ◽  
Textural Properties ◽  
Acid Strength ◽  
Titanium Hydroxide ◽  
Sulfated Titania ◽  
Solid Superacid ◽  
Different Temperatures ◽  
Ft Ir

Solid superacid sulfated titania (SO42-/TiO2) was prepared by impregnation of titanium hydroxide with an aqueous solution of (NH4)2SO4, and then calcined at different temperatures. The structural properties of these samples were investigated using XRD, BET, and DSC. Surface acidity of the catalysts were tested by FT-IR, XPS, and NH3-TPD. The SO42-/TiO2calcined at 340 °C showed the strongest acid strength. The catalytic activity of the catalysts was evaluated in the depolymerization of polythene terephthalate (PET) with ethylene glycol (EG) by varying different parameters. Experimental results were correlated to the textural properties and surface acidity. The catalyst SO42-/TiO2calcined at 340 °C exhibited maximum catalytic activity, with the conversion of PET as high as 72.9%, which may be due to the amorphous phase and the strongest acid strength. When the reaction temperature was at 194 °C, the conversion of PET was 100%, and the yield of the bis-2-hydroxyethyl terephthalate (BHET) monomer was 61.7%.

Characterization and Acid Catalytic Properties of NiO Supported on ZrO2 and Modified with MoO3

2007 ◽  
Vol 124-126 ◽  
pp. 1797-1800 ◽  
Author(s):  
Jong Rack Sohn ◽  
Dong Cheol Shin
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Acid Catalysis ◽  
Catalytic Properties ◽  
Orthorhombic Phase ◽  
Acid Strength ◽  
Two Dimensional ◽  
Ammonium Heptamolybdate ◽  
Cumene Dealkylation

Nickel oxide supported on zirconia and modified with MoO3 for acid catalysis was prepared by drying powdered Ni(OH)2-Zr(OH)4 with ammonium heptamolybdate aqueous solution, followed by calcining in air at high temperature. The characterization of prepared catalysts was performed using FTIR, Raman, XRD, and DSC. MoO3 equal to or less than 15 wt% was dispersed on the surface of catalyst as two-dimensional polymolybdate or monomolybdate, while for MoO3 above 15 wt%, crystalline orthorhombic phase of MoO3 was formed. The high acid strength and acidity were responsible for the Mo=O bond nature of the complex formed by the interaction between MoO3 and ZrO2. The catalytic activity for cumene dealkylation was correlated with the acidity of the catalyst measured by the ammonia chemisorption method

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