Liquid phase alkylation of anisole and phenol catalyzed by niobium phosphate

Pereira, Cynthia Cristina Mendes; Cruz, Marcus Henrique Campino de la; Lachter, Elizabeth R.

doi:10.1590/s0103-50532010000200025

Cited by 8 publications

(6 citation statements)

References 22 publications

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“…Several strategies have been proposed to improve bio-oil properties. An extensive amount of work has focused primarily on hydrodeoxygenation of phenolic compounds [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] while some work has focused on improving carbon retention and enhancing molecular weight mainly by alkylation reactions [19][20][21][22][23][24]. Molecular weight enhancement of bio-oil molecules may become important for the production of molecules with the appropriate length to use them as components of the gasoline and, particularly, of the diesel pools.…”

Section: Introductionmentioning

confidence: 99%

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Anaya

Zhang

Tan

et al. 2015

Journal of Catalysis

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a b s t r a c tThe liquid-phase hydroalkylation of m-cresol catalyzed by zeolite catalysts doped with noble metals was investigated at 473 K and 5200 kPa of H 2 . Metals (Pt and Pd) were incorporated in HY (Si/Al = 30) and HMor (Si/Al = 10) zeolites by incipient wetness impregnation. The structural properties of the samples were characterized by NMR, XPS, and BET. Hydroalkylation of m-cresol involves a series of steps that start with the ring saturation to 3-methylcyclohexanone (MCONE), which is the primary product and is further hydrogenated to methylcyclohexanol (MCNOL) on the metal function. This, in turn, is dehydrated on the acid sites to 3-methylcyclohexene, which readily alkylates the unreacted m-cresol to form bicyclic compounds that fall in the desirable fuel range. In these bifunctional catalysts, differences in intrinsic hydrogenation activity of metals play an important role in determining the final selectivity to alkylated products. In fact, the ratio of number of acid sites (n A ) to exposed metal sites (n M ) can be tuned to maximize the selectivity toward bicyclic compounds because this selectivity is determined by the fate of the intermediate 3-methylcyclohexene (MCENE). That is, if the C@C hydrogenation on the metal is fast compared to alkylation on the acid site, the selectivity decreases. However, if the hydrogenation is too slow, the overall product yield decreases. Thus, to optimize the hydroalkylation yield, a delicate metal/acid balance is required. Moreover, in the absence of metal, the zeolite would deactivate very quickly. Therefore, having the metal and acid functions together is also important for extending the catalyst life. Finally, it has been observed that 3D-pore zeolites, such as HY, are preferred over 1D-pore zeolites such as HMor, which sharply diminish the formation of alkylation compounds, despite being more acidic than HY.

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Section: Introductionmentioning

confidence: 99%

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Anaya

Zhang

Tan

et al. 2015

Journal of Catalysis

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“…The catalysts exhibited two broad peaks around 25° and 55°. No diffraction peaks for the NBO and NBP samples were observed, indicating that these materials presented an amorphous structure, consequently revealing their lack of crystalline organization, as described in the literature , , , , .…”

Section: Resultsmentioning

confidence: 90%

“…The specific areas obtained for the commercial NBP and NBO shows that these values are higher than those presented by other references [45,[52][53][54][55][56], probably because these catalysts were not submitted to calcination. These values can decrease when the catalysts are submitted to different pretreatment temperatures and distinct preparation methods [52,57]. Armaroli [53] and Ziolek [54] found specific areas in the ranges of 27-132 and 150-180 m 2 g -1 for NBO and NBP, respectively.…”

Section: Catalyst Propertiesmentioning

confidence: 99%

Kinetics of Soybean Oil Hydrolysis on Niobium Catalysts

et al. 2020

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The catalytic hydrolysis of soybean oil was used as an alternative for the production of monoglycerides (MG) and diglycerides (DG). The reactions were conducted in a stainless-steel tubular reactor in the temperature range of 240-290°C, on niobium phosphate (NBP) and niobium oxide (NBO) as catalysts. In the hydrolysis reactions at 270°C, the maximum selectivities of the products of interest were obtained at 22 % MG and 48 % DG for the reaction with NBP, and 7 % MG and 33 % DG with NBO, for 59 % and 36 % of triglyceride conversion in 10 min, respectively. The proposed kinetic model presented a good fit of the theoretical model with the experimental data, showing that the previous hypotheses considered for the mechanism development are suitable for describing the kinetics of soybean oil hydrolysis.

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“…[21][22][23][24] The IR spectrum of the niobium phosphate show a strong band due to the asymmetric vibration stretching mode of phosphate ion with a maximum at 1010 cm -1 . An additional strong band is found at 620 cm -1 in agreement with the spectrum of niobic acid, which could be due to Nb-O stretching modes.…”

Section: Resultsmentioning

confidence: 99%

“…18 Our group has been evaluating niobium catalysts 19 in benzylation and alkylation reactions and the results evidenced the high catalytic activity of niobium phosphate for these reactions. [20][21][22][23] However to the best of our knowledge, the use of niobium phosphate as catalysts for acetalization reactions has not been reported until now. Therefore the objective of this work is to report the performance of niobium phosphate and a comparison with Amberlyst 35 and p-toluenesulfonic acid in the acetalization reaction of hexanal with 2-ethyl-hexanol to prepare alkyl acetal to be used in drilling fluid research.…”

Section: Introductionmentioning

confidence: 99%

Acetalization of hexanal with 2-ethyl hexanol catalyzed by solid acids

Barros

Faísca

Lachter

et al. 2011

J. Braz. Chem. Soc.

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A atividade catalítica de sólidos ácidos como o fosfato de nióbio e a Amberlyst 35, uma resina trocadora de íons, foi avaliada na acetalização do hexanal com 2-etil-hexanol. Foram avaliadas a concentração do catalisador e a temperatura de reação na conversão do hexanal. A possibilidade de re-utilização do fosfato de nióbio também foi estudada e evidenciou ser possível re-utilizar este catalisador sem perda da atividade. O rendimento em acetal foi acima de 90% em condições brandas de reação.The catalyst activity of solid acids such as niobium phosphate and Amberlyst 35, an ion exchange resin, was evaluated in the acetalization of hexanal with 2-ethyl-hexanol. The catalyst loading and the reaction temperature were evaluated in the hexanal conversions. The possibility of recycling niobium phosphate was also studied, showing that it was possible to reuse this catalyst without significant loss in its catalytic activity. The yield in acetal was above 90% under mild conditions.

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Liquid phase alkylation of anisole and phenol catalyzed by niobium phosphate

Cited by 8 publications

References 22 publications

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Kinetics of Soybean Oil Hydrolysis on Niobium Catalysts

Acetalization of hexanal with 2-ethyl hexanol catalyzed by solid acids

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