Properties of modified zirconia used as friedel-crafts-acylation catalysts

Quaschning, V.; Deutsch, J.; Druska, Peter; Niclas, H.‐J.; Kemnitz, Erhard

doi:10.1006/jcat.1998.2098

Cited by 88 publications

(53 citation statements)

References 16 publications

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“…This result indicates that the solid acid amount increased after the Al incorporation, and that the total number of acid sites remained nearly constant, despite the differences in preparation temperatures of Al-incorporated diatomite. The former result is a consequence of the introduction of Al-OHs and Al-, and the latter result is due to the transformation of B acid sites (Al-OHs) into L acid sites (Al-) via the dehydroxylation of Al 13 after heating, consistent with the FTIR and 29 Si MAS NMR spectra results reported in our previous work [24].…”

Section: Resultssupporting

confidence: 89%

“…This band for Dt/Al 350 -NH 3 is hardly distinguished and is not observed in the curve of Dt/Al 500 -NH 3 . The weakening and disappearance of this NH 3 -desorption band for Al-incorporated diatomite is attributed to the decrease in number of diatomite Si-OHs, which react with Al 13 hydroxyl groups, as revealed by 29 Si MAS NMR spectra (see our previous report [24]). …”

Section: Resultsmentioning

confidence: 55%

“…The gaseous products were estimated using red litmus test papers and CaCl 2 for NH 3 and CO 2 , respectively. The mixed indicator contained 1% bromocresol green ethanol solution and 2% methyl red ethanol solution with a volume ratio of 3:1; the color of the indicator changed from red to green when the pH value of the solution was greater than 5.1 [28][29][30]. …”

Section: Evaluation Of the Catalytic Activity Of Diatomite And Its Almentioning

confidence: 99%

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Enhancement of diatomite solid acidity by Al incorporation, as evaluated by the catalytic effects on the thermal decomposition of 12-aminolauric acid

Deng

Dong

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 55%

Section: Evaluation Of the Catalytic Activity Of Diatomite And Its Almentioning

confidence: 99%

See 1 more Smart Citation

Enhancement of diatomite solid acidity by Al incorporation, as evaluated by the catalytic effects on the thermal decomposition of 12-aminolauric acid

Deng

Dong

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…It's well-known that the catalytic activity in both acetylation and benzoylation reactions can be owed to (i) the presence of Brønsted acid sites and (ii) on the extent of Brønsted-to-Lewis sites ratio [24,25]. For these reasons, FT-IR spectroscopy measurements have been resorted to in order to evaluate the acidic features of the samples.…”

Section: Resultsmentioning

confidence: 99%

Aerogel and xerogel WO3/ZrO2 samples for fine chemicals production

Signoretto

Ghedini

Menegazzo

et al. 2013

Microporous and Mesoporous Materials

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a b s t r a c t WO 3 /ZrO 2 systems were prepared by sol-gel technique using different procedures for the solvent extraction: evaporation in vacuum at room temperature (xerogel) and extraction in supercritical conditions (aerogel). Two reactions of industrial interest were investigated under mild conditions: (i) acylation of veratrole with acetic anhydride; (ii) acylation of anisole with benzoic anhydride. Several techniques were employed in order to study the influence of the synthetic parameters on texture and catalytic activity: N 2 physisorption, Fourier transformed-infrared spectroscopy, X-ray photoelectron spectroscopy, temperature programmed reduction and temperature programmed oxidation analyses. The solvent extraction strongly influences metal reducibility, surface area, pores organisation, W/Zr surface density and metallic interactions. The aerogel sample shows the best catalytic results for both conversion and yield. The supercritical extraction plays a central role especially in the recycling: by proper air activation, the aerogel sample attains the complete restoration of the catalytic activity even after three runs.

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“…Replacing homogeneous catalytic systems with heterogeneous ones is advantageous mainly because of easy catalyst recovery, reusability, and work-up of reaction products [4][5][6]. During the past decade, much attention has been paid to the replacement of homogeneous catalysts by solid acid catalysts such as zeolites [7,8] [9,10], clays [11,12], metal oxides [13], and modified silica [14].…”

Section: Introductionmentioning

confidence: 99%

Environmentally benign Friedel-Crafts benzylation over nano-TiO2/SO42-

2013

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During the past decade, much attention has been paid to the replacement of homogeneous catalysts by solid acid catalysts. Friedel-Crafts benzylation of toluene with benzyl chloride (BC) in liquid phase was carried out over highly active, nano-crystalline sulfated titania systems. These catalysts were prepared using the sol gel method. Modification was done by loading 3% of transition metal oxides over sulfated titania. Reaction parameters such as catalyst mass, molar ratio, temperature, and time have been studied. More than 80% conversion of benzyl chloride and 100% selectivity are shown by all the catalysts under optimum conditions. Catalytic activity is correlated with Lewis acidity obtained from perylene adsorption studies. The reaction appears to proceed by an electrophile, which involves the reaction of BC with the acidic titania catalyst. The catalyst was regenerated and reused up to four reaction cycles with equal efficiency as in the first run. The prepared systems are environmentally friendly and are easy to handle.

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Properties of modified zirconia used as friedel-crafts-acylation catalysts

Cited by 88 publications

References 16 publications

Enhancement of diatomite solid acidity by Al incorporation, as evaluated by the catalytic effects on the thermal decomposition of 12-aminolauric acid

Enhancement of diatomite solid acidity by Al incorporation, as evaluated by the catalytic effects on the thermal decomposition of 12-aminolauric acid

Aerogel and xerogel WO3/ZrO2 samples for fine chemicals production

Environmentally benign Friedel-Crafts benzylation over nano-TiO2/SO42-

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