Effects of the preparation methods on the performance of the Cu–Cr–Fe/γ-Al2O3 catalysts for the synthesis of 2-methylpiperazine

Bai, Guoyi; Fan, Xinxin; Wang, Hailong; Xu, Jianzhong; He, Fang; Ning, Huisen

doi:10.1016/j.catcom.2009.07.025

Cited by 14 publications

(8 citation statements)

References 19 publications

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“…The XRD patterns of Ni-Mo-P amorphous catalysts prepared under different sonication power within 30 min are shown in Fig. 1 (A), except the sample of NMP (60 W), others all have a relatively broad peak at about 45° , corresponding to the typical amorphous structure [4][5][6], indicating that the introduction of ultrasonic did not change the structure of the catalysts. However, as we can see, under 90 W, the XRD pattern becomes more sharply, and small wide peaks appear around 52° and 77°.…”

Section: Resultsmentioning

confidence: 99%

“…Owing to its unique isotropic nature and high concentration of coordinative unsaturated sites, amorphous alloy catalysts have higher activity, better selectivity, and stronger poison resistance than the corresponding crystalline catalysts, and recently they have been widely studied in hydrogenation reactions [1][2][3][4][5][6][7]. Addition of Mo can enhance its degree of disorder and dispersion, the metalloid such as B and P can stabilize the catalyst, and influence its activity and selectivity [5].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Liquid-Phase Selective Hydrogenation of Nitrobenzene over Ultrasonic-Assisted Ni-Mo-P Amorphous Catalyst

Dai

Liu

et al. 2012

AMR

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The Ni-Mo-P amorphous catalysts were prepared by chemical reduction method under different sonication conditions. The catalytic performance of the prepared catalysts in selective hydrogenation of nitrobenzene(NB) to aniline(AN) were characterized by XRD, BET, N2-adsorption, H2-TPR and H2-TPD. The results show that the introduction of ultrasonic can improve the dispersion of the active sites in the catalyst, the particle size of the catalyst is also smaller than the regular prepared Ni-Mo-P amorphous catalyst. And the influences of the sonication power and time on the catalysts were discussed and compared. The optimal sonication condition is 70 W within 25 min, its optimal reaction time is 150 min.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Liquid-Phase Selective Hydrogenation of Nitrobenzene over Ultrasonic-Assisted Ni-Mo-P Amorphous Catalyst

Dai

Liu

et al. 2012

AMR

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“…Sol-gel studies conducted on Mn-based catalysts have shown that structure has the largest effect on activity, which is dependent on the manufacturing method but independent of Mn content (Bai et al, 2009;Mohamed et al, 2007;Schmpf et al, 2002). Singoredjo et al (Singoredjo et al, 1992) observed that Mnbased catalysts displayed the highest activity in the temperature range of 107-297 C and that the activity was dependent on the oxidation state of manganese.…”

Section: Introductionmentioning

confidence: 99%

Improving the activity of Mn/TiO₂ catalysts through control of the pH and valence state of Mn during their preparation

Kim

Hong

2012

Journal of the Air & Waste Management Association

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In this study, the authors investigated the influence of the valence state of Mn on the efficacy of selective catalytic reduction using a Mn-based catalyst. The nitrogen oxides (NOx) conversion rate of the catalyst was found to be dependent on the type of TiO2 support employed and on the temperature, as the catalyst showed an excellent conversion of > 80% at a space velocity of 60,000 hr(-1) when the temperature was above 200 degrees C. Brunauer-Emmett-Teller, X-ray diffraction, and X-ray photoelectron spectroscopy analyses confirmed that catalyst displaying the highest activity contained the Mn4+ species and that its valence state was highly dependent on the pH during the catalyst preparation.

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“…Therefore, it is desirable to develop an effective method on the mild acylation of pyrrole with good stability and investigate the relationship of activity with the structure of the catalysts. On the other hand, there has been an increasing interest in the use of ultrasound in chemical reactions and catalysts preparation because of its unique chemical effects arising from acoustic cavitation [14][15][16][17]. Furthermore, acid modifications have been proven to be important for improving the activity of zeolites [18,19].…”

Section: Introductionmentioning

confidence: 99%

Friedel–Crafts acylation of pyrrole over ultrasonic-assisted phosphoric acid-modified Hβ zeolite

Bai

Yang

et al. 2011

Res Chem Intermed

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Friedel-Crafts acylation of pyrrole with acetic anhydride was studied over different zeolites and an ultrasonic-assisted phosphoric acid-modified Hb (P-Hb-US) zeolite was found to have the best catalytic performance among all the zeolites examined. The conversion of acetic anhydride reached 98.8% and the selectivity to acetylpyrroles was 97.0% under the optimized conditions. The high activity of the P-Hb-US zeolite is attributed to the increase of weak acid sites, caused by the synergistic effect between the phosphoric acid modification and ultrasound. Moreover, the carbonaceous deposits, mainly due to the adsorption of reactants and products, on the surface acid sites and the blockage of the pores is believed to be the reason for the deactivation of the reused P-Hb-US zeolite, confirmed from the Brunauer-Emmett-Teller (BET) method, scanning electron microscopy, and X-ray photoelectron spectroscopy. Furthermore, the catalyst activity can be recovered effectively by a subsequent calcination.

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Effects of the preparation methods on the performance of the Cu–Cr–Fe/γ-Al2O3 catalysts for the synthesis of 2-methylpiperazine

Cited by 14 publications

References 19 publications

Liquid-Phase Selective Hydrogenation of Nitrobenzene over Ultrasonic-Assisted Ni-Mo-P Amorphous Catalyst

Liquid-Phase Selective Hydrogenation of Nitrobenzene over Ultrasonic-Assisted Ni-Mo-P Amorphous Catalyst

Improving the activity of Mn/TiO₂ catalysts through control of the pH and valence state of Mn during their preparation

Friedel–Crafts acylation of pyrrole over ultrasonic-assisted phosphoric acid-modified Hβ zeolite

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Effects of the preparation methods on the performance of the Cu–Cr–Fe/γ-Al2O3 catalysts for the synthesis of 2-methylpiperazine

Cited by 14 publications

References 19 publications

Liquid-Phase Selective Hydrogenation of Nitrobenzene over Ultrasonic-Assisted Ni-Mo-P Amorphous Catalyst

Liquid-Phase Selective Hydrogenation of Nitrobenzene over Ultrasonic-Assisted Ni-Mo-P Amorphous Catalyst

Improving the activity of Mn/TiO2 catalysts through control of the pH and valence state of Mn during their preparation

Friedel–Crafts acylation of pyrrole over ultrasonic-assisted phosphoric acid-modified Hβ zeolite

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Improving the activity of Mn/TiO₂ catalysts through control of the pH and valence state of Mn during their preparation