Pd-Fe/SiO2 Catalysts in the Hydrogenation of 2,4-Dinitrotoluene

Pinna, Francesco; Selva, Maurizio; Signoretto, Michela; Strukul, Giorgio; Boccuzzi, F.; Benedetti, Alvise; Canton, Patrizia; Fagherazzi, G.

doi:10.1006/jcat.1994.1354

Cited by 64 publications

(41 citation statements)

References 17 publications

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“…2.2.2 Effect of temperature. Generally, the aqueous phase reforming of alcohol over Raney Ni takes place at 423-530 K [24,25] , while the hydrogenation of nitro aromatic compounds and N-alkylation of aromatic amine over Raney Ni operate at 333-393 K [2][3][4][5] and 393-453 K [16][17][18][19][20] , respectively. Therefore, the optimization of reaction temperature is important to achieve a good coincidence of these three reactions in the system composed of "nitrobenzene + ethanol."…”

Section: Effect Of Reaction Conditions On the Catalytic Performancementioning

confidence: 99%

“…However, some special facilities for hydrogen production, reservation, and transportation are required in the traditional hydrogenation process. Currently, N-alkylation of aromatic amines with alkylating agents to produce N-alkyl arylamines is accompanied by the great challenge of the rigorous requirements for the equipment, hard purification of the products, and treatment of the waste water due to the occurrence of N,N-dialkylation using mineral acid, H 2 SO 4 , H 3 PO 4 , and hydrochloride as catalysts [6,7] . Gas-phase N-alkylation of aromatic amine using zeolites (ZSM-5, KY, NaX, CaY) [8][9][10][11] , metallic oxide [12][13][14] or metallic salt [12,15] instead of mineral acids as catalysts may avoid the equipment corrosion, but it is difficult to obtain an ideal selectivity for the desired product.…”

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confidence: 99%

“…These compounds are generally synthesized through the formation of aromatic amines from the chemical reduction or liquid phase catalytic hydrogenation of nitro aromatic compounds, and then the aromatic amines are reacted with alkylating agents such as alcohols, ether, and alkyl halides, to form N-alkyl arylamines over catalysts. From the viewpoint of environmentally benign, the liquid phase catalytic hydrogenation of nitro aromatic compounds over Raney Ni, Raney Cu and Pd, Pt supported on activated carbon, or Al 2 O 3 as catalysts is widely used in the synthesis of aromatic amines [1][2][3][4] , instead of the chemical reduction using iron, zinc powder, or sodium sulfide, which produce mass wastes [5] . However, some special facilities for hydrogen production, reservation, and transportation are required in the traditional hydrogenation process.…”

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confidence: 99%

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One pot synthesis of N-ethylaniline from nitrobenzene and ethanol

Zhang

Xiang

et al. 2008

Sci. China Ser. B-Chem.

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A novel method for the one pot synthesis of N-alkyl arylamines from nitro aromatic compounds and alcohols is proposed through the combination of the aqueous-phase reforming of alcohol for hydrogen production, the reduction of nitro aromatic compounds for the synthesis of aromatic amine and the N-alkylation of aromatic amine for the production of N-alkyl arylamine over an identical catalyst under the same conditions of temperature and pressure in a single reactor. In this process, hydrogen generated from the aqueous-phase reforming of alcohols was used in-situ for the hydrogenation of nitro aromatic compounds for aromatic amine synthesis, followed by N-alkylation of aromatic amine with alcohols to form the corresponding N-alkyl arylamines at a low partial pressure of hydrogen. For the system composed of nitrobenzene and ethanol, under the conditions of 413 K and P N 2 = 1 MPa, the conversion degrees of nitrobenzene and aniline were 100%, the selectivity to N-ethylaniline and N, N-diethylaniline were 85.9% and 0%-4%, respectivity, after reaction for 8 h at the volumetric ratio of nitrobenzene : ethanol : water = 10 : 60 : 0. The selectivity for N, N-diethylaniline production is much lower than that through the traditional method. In this process, hydrogen and aromatic amines generated from the aqueous-phase reforming of alcohols and hydrogenation of nitro aromatic compounds, respectively, could be promptly removed from the surface of the catalyst due to the occurrence of in-situ hydrogenation and N-alkylation reactions. Thus, this may be a potential approach to increase the selectivity to N-alkyl arylamine.

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Section: Effect Of Reaction Conditions On the Catalytic Performancementioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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One pot synthesis of N-ethylaniline from nitrobenzene and ethanol

Zhang

Xiang

et al. 2008

Sci. China Ser. B-Chem.

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“…Pinna et al [48] reported the XRD patterns of Pd-Fe/SiO 2 and observed a shift in the 2h value of aPd peak by about 0.2°. This shift in the peak was related to a Pd-Fe alloy phase.…”

Section: Studies On Low-dispersed Catalystsmentioning

confidence: 96%

Hydrodechlorination of chlorobenzene over supported metal catalysts

et al. 2006

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The use of supported Pd catalysts, with low and high metal content, for the hydrodechlorination of chlorobenzene is presented in this article. Application of microwave irradiation during preparation of catalysts resulted in the synthesis of large Pd particles at moderate temperatures. The nature of the support played a key role in the formation of cationic Pd species. The extent of interaction of the Pd species with the support, the nature of metal precursor, particularly the residual chlorine on the surface were found to significantly affect the activity of the catalysts. In the case of bimetallic catalysts also microwave heating resulted in creation of bigger particles of Pd compared to those observed in conventionally heated catalysts. Besides, it minimized alloy formation as a result of which the activity of the catalysts in hydrodechlorination was found to be higher compared to that observed on conventionally prepared catalysts. Contrary to the general observation that low dispersed Pd catalysts are preferable for high stability, by means of the deposition-precipitation method adopted for catalyst preparation it was demonstrated that even highly dispersed (low Pd containing) catalysts can exhibit comparable activity and stability. An analysis of the nature of Pd species and its role in the stability of the catalysts is presented.

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“…The catalytic hydrogenation of nitrobenzene to aniline includes multistep hydrogenation, in which at least two intermediates (nitrosobenzene and phenylhydroxylamine) may be formed through the semihydrogenation reaction [42]. It has been found that using different catalysts, the mainly formed intermediate is different [43,44].…”

Section: Catalytic Performance Of Pt-containing Mcm-41 Materials For mentioning

confidence: 99%