Chemoselective Hydrogenation of Benzoic Acid over Ni–Zr–B–PEG

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Chemoselective Hydrogenation of Benzoic Acid over Ni−Zr−B− PEG(800) Nanoscale Amorphous Alloy in Water Guoyi Bai,*,† Xin Wen,†,‡ Zhen Zhao,† Fei Li,† Huixian Dong,† and Mande Qiu† †

Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei, 071002, People’s Republic of China ‡ Bioreactor and Protein Drug Research and Development Center of Hebei Universities, Hebei Chemical and Pharmaceutical College, Shijiazhuang, Hebei, 050026, People’s Republic of China ABSTRACT: A Zr and polyethylene glycol 800 [PEG(800)] modified Ni−B [Ni−Zr−B−PEG(800)] amorphous alloy catalyst showed excellent catalytic performance, comparable to noble metal catalysts, in the chemoselective hydrogenation of benzoic acid to cyclohexane carboxylic acid. The synergistic effect between Zr and PEG(800) is suggested to decrease significantly the agglomeration of the active Ni species, causing the Ni−Zr−B−PEG(800) to have a larger BET area, smaller particle size, and the greatest number of Ni active centers, accounting for its high activity in water. The solvent effect on the selectivity was studied in detail. The high polarity of the water favors the orientation of carboxyl group toward the solvent, resulting in the selective hydrogenation of the aromatic ring, thus leading to a high selectivity for production of cyclohexane carboxylic acid compared to that occurring in the low polarity cyclohexane.

1. INTRODUCTION In recent years, nanoscale amorphous alloys have been widely used in the field of catalysis and hydrogen storage due to their excellent physical and chemical properties, such as short-range order, long-range disorder, and good dispersion.1−8 In particular, metal-doped Ni−B amorphous alloys have attracted much attention owing to their excellent catalytic performance, low cost, and environmentally benign nature.9−16 For instance, Li et al. have reported that Co-doped Ni−B amorphous alloys exhibited higher activity and chemoselectivity than the undoped system in the liquid phase hydrogenation of acetonitrile, and the effect of the quantity of Co was investigated in detail.16 Although addition of metals to amorphous alloys can increase dispersion and therefore their activities, agglomeration phenomena still exist sometimes leading to decreased activity, so it continues to be of great importance to find other effective modifiers.17,18 Accordingly, polymers have been employed to prevent agglomeration of active components in catalysts, resulting in better dispersion and higher activity in catalytic hydrogenation.19−24 For instance, Liaw et al. have reported that the particle sizes of a Co−Ni−B catalyst can be effectively controlled by using polyvinylpyrrolidone (PVP) as a modifier and the polymer-modified catalyst was more active than the unmodified one in the hydrogenation of unsaturated aldehydes.21 Recently, we found soluble polymers to be effective in inhibiting the agglomeration of the active Ni particles in Ni−B amorphous alloy catalysts, thus leading to higher activities in the chemoselective hydrogenation of benzophenone.22 Cyclohexane carboxylic acid (CCA) is an important organic intermediate for the synthesis of pharmaceuticals, such as praziquantel and ansatrienin.25,26 Catalytic hydrogenation of benzoic acid (BA) is the most effective method to obtain CCA.27 Noble metal catalysts, including Pd/C,28 Rh/C,29 PdxRuy,30 RuPt,31 and platinum nanowire,32 have been widely © 2013 American Chemical Society

applied in this transformation, and all exhibit high activities. For example, Pd/activated carbon has been used in the selective hydrogenation of BA to CCA in supercritical CO2 fluid under a high pressure (11.0 MPa) of hydrogen, with the supercritical CO2 fluid being proposed to be effective in sweeping the organic substances from the pores of the catalyst and maintaining particle sizes during the run.33 However, the high price of noble metal catalysts has limited their further application in industry. Raney Ni is an attractive catalyst in the hydrogenation of BA due to its much lower cost,34 whereas its pyrophoric nature35 and the potential for environmental pollution, mainly from waste alkali solution in its preparation, have become increasingly problematic in industrial applications. Therefore, there remains a need to find suitable cost-effective catalysts for the hydrogenation of BA. To the best of our knowledge, no work on the hydrogenation of BA over amorphous alloy catalysts has been reported; therefore, we report herein our recent research on the hydrogenation of BA to CCA over nanoscale amorphous alloys. A series of nanoscale metal and polymer modified Ni−B amorphous alloy catalysts was prepared by chemical reduction and tested in the chemoselective hydrogenation of BA as a replacement for expensive noble metal catalysts. A Zr and polyethylene glycol 800 [PEG(800)] modified Ni−B [Ni−Zr− B−PEG(800)] amorphous alloy shows good catalytic performance in this reaction. The synergistic effect between Zr and PEG(800) can decrease the agglomeration of the active species and improve the catalyst’s activity. Furthermore, the solvent effect on the selectivity was studied and discussed. Received: Revised: Accepted: Published: 2266

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2. EXPERIMENTAL SECTION 2.1. Preparation of Modified Ni−B Amorphous Alloy Catalyst. All chemicals were purchased from Baoding Huaxin Reagent and Apparatus Co., Ltd. and were used without further purification. Metal- and polymer-modified Ni−B amorphous alloys were prepared by chemical reduction. A typical procedure is as follows. An aqueous solution of 1.0 M KBH4 and 0.2 M NaOH (25 mL) was added dropwise to 0.6 M NiCl2·6H2O and 15 mM of the soluble salts of Ce, Ba, Fe, La, and Zr (X) (10 mL) in a molar ratio of Ni/X = 40/1. The mixture was then stirred for 30 min with cooling in an ice bath to furnish a black precipitate. When bubbles ceased to appear, the precipitate was filtered, washed with deoxygenated distilled water several times until the washings were at pH 7, and then further washed with absolute ethanol three times to replace residual water and stored under absolute ethanol. The catalysts so obtained are denoted as “Ni−X−B”. When polymers (0.5 g) were also added to the NiCl2·6H2O and soluble metal salt solutions during the preparation, the catalysts so obtained are denoted as “Ni−X−B−p” (“p” refers to the nature of the polymer). Raney nickel was prepared by alkali leaching of Ni− Al alloy using the conventional method.34 2.2. Catalyst Characterization. Bulk compositions were measured by inductively coupled plasma analysis (ICP) on a Varian Vista-MPX spectrometer. The BET surface area was assessed using a Micromeritics Tristar II 3020 surface area and pore analyzer. X-ray diffraction (XRD) patterns were recorded on a Bruker D8-ADVANCE X-ray diffractometer. Transmission electron microscopy (TEM) and selected area electron diffraction measurements (SAED) were obtained with a FEI Tecnai G2 microscope. Scanning electron microscopy (SEM) was performed on a JEOL JSM-7500 electron microscope. H2chemisorption and temperature programmed desorption of H2 (H2-TPD) were carried out using a TP-5000 instrument supplied by Xianquan Ltd. 2.3. Catalyst Activity Test and Product Analysis. Chemoselective hydrogenation of BA (Scheme 1) was

3. RESULTS AND DISCUSSION 3.1. Catalyst Selection. A series of metal-doped Ni−B amorphous alloy catalysts was prepared and tested in the chemoselective hydrogenation of BA, and the results are listed in Table 1. It is apparent that the undoped Ni−B showed poor Table 1. Hydrogenation of BA over Metal-Doped Ni−B Amorphous Alloysa catalyst

conversion of BA (%)

selectivity for CCA (%)

yield of CCA (%)

Ni−B Ni−Ce−B Ni−Ba−B Ni−Fe−B Ni−La−B Ni−Zr−B Raney Ni

7.8 44.5 24.1 24.9 33.1 64.9 58.5

82.6 99.2 91.0 98.0 95.3 90.6 97.5

6.4 44.8 21.9 24.4 31.5 58.8 57.0

a Reaction conditions: BA (3.0 g), catalyst (0.5 g), H2O (60 mL), 423 K, initial P(H2) = 4 MPa, and reaction time 4 h.

activity (only 7.8% conversion) in this transformation, probably due to the resistance of electron-deficient aromatic substrates to undergo hydrogenation without recourse to noble metal catalysts.30,36−38 Gratifyingly, all the metal-doped Ni−B amorphous alloy catalysts exhibited higher activity than the undoped system. Particularly noteworthy, the Ni−Zr−B catalyst showed the best yield (58.8%), superior to that of Raney Ni (57.0%), but its conversion (64.9%) was still lower than desired. Thus, it was desirable further to increase its activity. Considering the benefit of polymer modification in our previous studies,22 a series of polymers was then used as modifiers for the Ni−Zr−B amorphous alloy catalyst in an attempt to improve its activity in the BA hydrogenation, and the results are summarized in Table 2. It was shown that Table 2. Hydrogenation of BA over Polymer-Modified Ni− Zr−B Amorphous Alloysa

Scheme 1. Products from Divergent Pathways of Hydrogenation of BA over Ni-Based Amorphous Alloy

catalyst

conversion of BA (%)

selectivity for CCA (%)

yield of CCA (%)

Ni−Zr−B Ni−Zr−B−PEG(600) Ni−Zr−B−PEG(800) Ni−Zr−B−PEG(1000) Ni−Zr−B−PEG(2000) Ni−Zr−B−PVP Ni−Zr−B−PAM Ni−Zr−B−PVA

64.9 74.5 93.5 70.4 68.5 46.2 30.2 29.7

90.6 89.2 93.6 88.1 96.1 78.6 62.1 89.4

58.8 66.5 87.5 62.0 65.8 36.3 18.8 26.6

a Reaction conditions: BA (3.0 g), catalyst (0.5 g), H2O (60 mL), 423 K, initial P(H2) = 4 MPa, and reaction time 4 h.

conducted in a 100 mL stainless steel autoclave equipped with a magnetically driven mechanical stirrer and an electric heating system. BA (3.0 g), H2O (60 mL), and catalyst (0.5 g) were mixed in the autoclave, and then the reactor was filled with H2 to 1.0 MPa three times followed by evacuation to displace residual air. The autoclave was then pressurized with H2 to 4.0 MPa and heated to 423 K. On reaching 423 K, the reaction was initiated by stirring the reaction mixture vigorously, and it was allowed to proceed for 4 h. Gas chromatography equipped with a 30 m SE-54 capillary column was used to analyze the reaction mixtures. The structures of the products were identified using gas chromatography−mass spectroscopy (GC−MS) on an Agilent 5975C spectrometer.

modification with PEG markedly improved the activity of Ni− Zr−B and a Ni−Zr−B−PEG(800) amorphous alloy catalyst showed the best conversion (93.5%)even higher than that of the Pd-based catalyst (80.0%) reported by Anderson.39 In contrast, PVP, polyacrylamide (PAM), and polyvinyl alcohol (PVA) modified amorphous alloys revealed decreased activities compared to Ni−Zr−B. It would appear that the low solubilities of PVP, PAM, and PVA made them only partially soluble in the precursor mixtures to give slightly viscous solutions, resulting in the in situ generated Ni−Zr−B particles 2267

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Table 3. Selected Physicochemical Properties of Ni−B Amorphous Alloys

a

catalyst

composition (atomic ratio)a

surf. area (m2/g)

pore vol (cm3/g)

pore size (nm)

H2-chemisorption (cm3/g)

Ni−B Ni−Zr−B Ni−Zr−B−PEG(800)

Ni1.00B0.40 Ni1.00Zr0.03B0.41 Ni1.00Zr0.03B0.40

22 40 50

0.05 0.11 0.14

9.2 10.7 10.9

0.27 0.33 0.45

Based on ICP results.

Zr−B−PEG(800), in which a successive diffraction halo was observed, in good agreement with the XRD results. The surface morphology and size distributions of the amorphous alloy catalysts were recorded by TEM, as shown in Figure 2a−c. It appears that each sample displayed approximately spherical morphology, as supported by SEM (Figure 2d), and consistent with other reported Ni-based amorphous alloy catalysts.42 The agglomeration phenomenon was apparent in the Ni−B catalyst and its size distribution was found to be 15−111 nm. Fortunately, the particle size of Ni− Zr−B markedly decreased and the distribution narrowed to 13−44 nm with the addition of Zr, implying that Zr favors the dispersion of the amorphous alloy particles,43 in agreement with the BET surface area results (Table 3). The particle size of Ni−Zr−B−PEG(800) further decreased and the size range narrowed to 10−27 nm with the addition of PEG(800), suggesting further inhibition of the agglomeration, accounting for its largest BET surface area and highest activity of the catalysts studied. On the other hand, no evidence for the existence of PEG(800) on the surface of Ni−Zr−B−PEG(800) could be found from the TEM and SEM investigation. Thus, we propose that most of the PEG(800) was removed during washing in the preparation process and its main role was to prevent agglomeration of the amorphous alloy particles in the reduction process resulting in more active Ni species, as we have discussed previously22 and in accordance with the ICP and H2-chemisorption results. Figure 3 shows the H2-TPD profiles of the three samples. For Ni−B, two desorption peaks were observed, with the peak at 593 K being larger than that at 453 K, indicating the presence of two different adsorbing sites. The Ni−Zr−B catalyst also exhibited two desorption peaks, but the higher temperature peak had shifted to a relatively lower temperature (573 K) and the lower temperature peak was larger than that of Ni−B. In contrast, one strong peak at about 473 K, together with a shoulder at about 563 K, was observed from the H2-TPD profile of Ni−Zr−B−PEG(800). Thus, it can be concluded that the active Ni centers had a trend to become uniform in the presence of Zr and PEG(800), which can be attributed to the synergistic effect between Zr and PEG(800),44 showing positive effect on Ni−Zr−B−PEG(800) structures and making it more active than Ni−Zr−B and Ni−B−PEG(800). Furthermore, it is apparent that the hydrogen desorption peaks of Ni−Zr−B− PEG(800) are larger than those of the other two catalysts, especially the lower temperature peak, indicating that the addition of Zr and PEG(800) favors the dispersion of nanoparticles in this catalyst, resulting in the formation of more active centers and in agreement with the H 2 chemisorption results in Table 3. In combination with the experimental results, it also reveals that the low temperature hydrogen absorbing site should be more beneficial to the hydrogenation of BA to CCA. 3.3. Effect of Solvents. The selective hydrogenation of aromatic compounds with both aromatic rings and other reducible groups usually requires severe conditions over non-

becoming adsorbed onto the surface of the undissolved polymers, and accounting for the low activities of these three modified catalysts. Considering that the conversion of BA over Ni−B−PEG(800) was only 16.9%, Zr is believed to be more influential on the high activity of Ni−Zr−B−PEG(800) compared to PEG(800). Thus, the observation of this phase of studies led to the conclusion that addition of a small amount of Zr and PEG(800) can remarkably improve the activity of Ni−B amorphous alloy due to the synergistic effect between Zr and PEG(800), and Ni−Zr−B−PEG(800) was finally chosen as the optimal catalyst for the chemoselective hydrogenation of BA to CCA. 3.2. Catalyst Characterization. The compositions, BET surface areas, and H2-chemisorptions of Ni−B, Ni−Zr−B, and Ni−Zr−B−PEG(800) were measured, and selected results are shown in Table 3. It was found that the relative contents of B and Zr were almost identical in the three catalysts studied, implying that the addition of Zr and PEG(800) did not affect the composition and ratio of the catalysts. In contrast, addition of Zr manifestly increased the BET surface area, pore volume, and pore size of the catalyst. Moreover, further modification with PEG(800) continued to increase these values. Thus, Ni− Zr−B−PEG(800) had the largest BET surface area, pore volume, and pore size among the catalysts studied. With respect to H2-chemisorption, it showed a similar trend to the increase in BET surface area. The H2-chemisorption value of Ni−Zr−B increased from 0.27 to 0.33 m3/g with the addition of Zr and further increased to 0.45 m3/g with the addition of PEG(800). Thus, Ni−Zr−B−PEG(800) showed the highest H2-chemisorption value in the three catalysts, accounting for its highest catalytic activity. Figure 1 shows XRD patterns of the three catalysts. As can be seen, only one broad diffraction peak was observed around 2θ = 45° in all the XRD patterns, indicative of a typical Ni−B amorphous structure, indicating that the amorphous structure of Ni−B had not been changed by the addition of Zr or PEG(800).40,41 The inset in Figure 1 is the SAED image of Ni−

Figure 1. XRD patterns of amorphous alloy catalysts (a) Ni−B, (b) Ni−Zr−B, and (c) Ni −Zr−B−PEG(800). The inset is the SAED image of Ni−Zr−B−PEG(800). 2268

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Figure 2. TEM images and size distributions of amorphous alloy catalysts (a) Ni−B, (b) Ni−Zr−B, and (c) Ni−Zr−B−PEG(800). (d) SEM image of Ni−Zr−B−PEG(800).

Table 4. Hydrogenation of Benzoic Acid in Various Solvents over Ni−Zr−B−PEG(800)a

entry

solvent

conversion of BA (%)

selectivity for CCA (%)

1 2 3 4 5 6

water dioxane tetrahydrofuran cyclohexane ethanolb butan-2-olc

93.5 99.7 87.8 99.6 78.7 72.7

93.6 69.2 56.1 42.7 1.1 58.6

selectivity for benzyl alcohol (%)

yield of CCA (%)

6.4 30.8 43.9 57.3 0.9 5.9

87.5 69.0 49.3 42.5 8.7 42.6

a

Reaction conditions: BA (3.0 g), catalyst (0.5 g), solvent (60 mL), 423 K, initial P(H2) = 4 MPa, and reaction time 4 h. bOther byproducts (selectivity): ethyl benzoate (71.5%); ethyl cyclohexane carboxylate (26.6%). cOther byproducts (selectivity): butan-2-yl benzoate (12.8%); butan-2-yl cyclohexane carboxylate (22.7%).

Figure 3. H2-TPD profiles of amorphous alloy catalysts (a) Ni−B, (b) Ni−Zr−B, and (c) Ni−Zr−B−PEG(800).

noble metal catalysts,45−47 with the potential to lead to the hydrogenation of the latter functionality. The chemoselective hydrogenation of BA was therefore studied in a series of solvents over Ni−Zr−B−PEG(800) to investigate the effect of solvents on the selectivity, and the results are shown in Table 4. As can be seen, in the case of water, a highly polar solvent, the selectivity for CCA reached 93.6%, whereas the selectivity decreased significantly with decreasing polarity of the solvents. For instance, in the cases of 1,4-dioxane and tetrahydrofuran, the selectivity for CCA decreased to 69.2 and 56.1%, respectively. Nevertheless our result in 1,4-dioxane was still

superior to the observation of Anderson with only 3% yield of CCA over a Pd-based catalyst.48 Thus, our catalytic system involving Ni−Zr−B−PEG(800) catalyst exhibits a better solvent profile with 99.7% conversion and 69.2% selectivity for CCA in 1,4-dioxane. In the case of the nonpolar solvent cyclohexane, the selectivity for CCA decreased to only 42.7% but the selectivity for benzyl alcohol increased to 57.3%, in keeping with the results of Malyala when using n-hexane,49 showing that production of benzyl alcohol increases commen2269

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catalyst was significantly inhibited by the combination of Zr and PEG(800), resulting in Ni−Zr−B−PEG(800) having the largest BET surface area, the smallest particle size, and the greatest number of Ni active centers of the catalysts studied, accounting for its highest activity in this reaction. The effect of solvent was investigated, and water was found to benefit the selectivity for hydrogenation of the aromatic ring, possibly by inducing orientation of the carboxyl group to the solvent. Owing to its good activity, environmentally friendly nature, and low cost, the catalytic system involving Ni−Zr−B−PEG(800) as catalyst and water as solvent is proposed as an optimal system to produce CCA in large-scale processes.

surate with the decrease of the polarity of the solvents. Thus, it can be concluded that the polarity of a solvent has a significant effect on the selectivity for CCA. However, it must be pointed out that this rule does not fit for solvents that can react with the substrate. Using ethanol, a moderately polar solvent, the selectivity for CCA was only 1.1%, much lower even than that of the nonpolar cyclohexane, with esterification rather than hydrogenation occurring under the reaction conditions, leading mainly to ethyl benzoate (71.5% selectivity). Furthermore, even the CCA formed reacted further with the ethanol to produce ethyl cyclohexane carboxylate (26.6% selectivity), resulting in the very low selectivity for CCA. In contrast, in the case of a sterically hindered alcohol, such as butan-2-ol, the selectivity for CCA improved notably to 58.6%, although butan-2-yl benzoate and butan-2-yl cyclohexane carboxylate were also obtained in relative amounts of 12.8 and 22.7%, respectively. Thus, water is the solvent of choice for BA hydrogenation due to the high selectivity of this combination as well as the green nature of the system. The nature of the solvent has been demonstrated to have a crucial influence on both catalyst activity and selectivity in catalytic hydrogenation,48−55 but more work is needed to clarify the source of such influence. We propose that the polar carboxyl group and nonpolar aromatic ring of BA, in the presence of a polar solvent, will markedly influence its adsorption behavior on the surface of the Ni−Zr−B− PEG(800) catalyst with hydrogen bonding existing between the carboxyl group and the water.39,48 Thus, the carboxyl group of BA will face toward the solvent and the aromatic ring will be oriented toward the catalyst, 56 presenting an optimal adsorption interaction between the substrate and the catalyst (Figure 4). In the subsequent hydrogenation, the carboxyl

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AUTHOR INFORMATION

Corresponding Author

*Tel.: +86-312-5079359. Fax: +86-312-5937102. E-mail: [email protected]. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS The authors thank Prof. Laurence M. Harwood and Prof. Xinwu Ba for their kind help. Financial support from the National Natural Science Foundation of China (20806018) and the Natural Science Foundation of Hebei Province (B2011201017) is gratefully acknowledged.

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REFERENCES

(1) Fang, J.; Chen, X. Y.; Liu, B.; Yan, S. R.; Qiao, M. H.; Li, H. X.; He, H. Y.; Fan, K. N. Liquid-phase chemoselective hydrogenation of 2ethylanthraquinone over chromium-modified nanosized amorphous Ni-B catalysts. J. Catal. 2005, 229, 97. (2) Wang, Y.; Guo, C. X.; Wang, X.; Guan, C.; Yang, H. B.; Wang, K.; Li, C. M. Hydrogen storage in a Ni-B nanoalloy-doped threedimensional graphene material. Energy Environ. Sci. 2011, 4, 195. (3) Li, H.; Liu, J.; Xie, S. H.; Qiao, M. H.; Dai, W. L.; Li, H. X. Highly active Co-B amorphous alloy catalyst with uniform nanoparticles prepared in oil-in-water microemulsion. J. Catal. 2008, 259, 104. (4) Li, L. L.; Han, C. X.; Yang, L.; Wang, X. Y.; Zhang, B. G. The Nature of PH3 decomposition reaction over amorphous CoNiBP alloy supported on carbon nanotubes. Ind. Eng. Chem. Res. 2010, 49, 1658. (5) Kukula, P.; Gabova, V.; Koprivova, K.; Trtik, P. Selective hydrogenation of unsaturated nitriles to unsaturated amines over amorphous CoB and NiB alloys doped with chromium. Catal. Today 2007, 121, 27. (6) Xie, S. H.; Li, H. X.; Li, H.; Deng, J. F. Selective hydrogenation of stearonitrile over Ni-B/SiO2 amorphous catalysts in comparison with other Ni-based catalysts. Appl. Catal., A 1999, 189, 45. (7) Pei, Y.; Zhou, G. B.; Luan, N.; Zong, B. N.; Qiao, M. H.; Tao, F. Synthesis and catalysis of chemically reduced metal-metalloid amorphous alloys. Chem. Soc. Rev. 2012, 41, 8140. (8) Alexander, A. M.; Hargreaves, J. S. J. Alternative catalytic materials: carbides, nitrides, phosphides and amorphous boron alloys. Chem. Soc. Rev. 2010, 39, 4388. (9) Bai, G. Y.; Niu, L. B.; Zhao, Z.; Li, N.; Li, F.; Qiu, M. D.; He, F.; Chen, G. F.; Ma, Z. Ni-La-B amorphous alloys supported on SiO2 and γ-Al2O3 for selective hydrogenation of benzophenone. J. Mol. Catal. A: Chem. 2012, 363−364, 411. (10) Wen, H. L.; Yao, K. S.; Zhang, Y. D.; Zhou, Z. M.; Kirschning, A. Catalytic transfer hydrogenation of aromatic nitro compounds in presence of polymer-supported nano-amorphous Ni-B catalyst. Catal. Commun. 2009, 10, 1207. (11) Hou, Y. J.; Wang, Y. Q.; Mi, Z. T. The beneficial effects of molybdenum addition on Ni-B amorphous alloy catalyst used in 2ethylanthraquinone hydrogenation. J. Mater. Sci. 2005, 40, 6585.

Figure 4. Proposed mechanism for adsorption and hydrogenation of BA in solvents with different polarities.

group of BA will be surrounded by and interacting with water, lowering its contact with the active Ni on the surface of Ni− Zr−B−PEG(800) and inhibiting its hydrogenation. At the same time, the aromatic ring of BA will be absorbed by the active Ni and selectively hydrogenated, leading to the desired CCA as the final product.57 On the contrary, in the case of the low polarity solvents, lacking the ability to form a hydrogen bond with the carboxyl group, the BA is adsorbed with much less regular orientation, lowering the selectivity for CCA. This phenomenon was most evident using the nonpolar cyclohexane as a solvent (Figure 4).

4. CONCLUSIONS A novel Ni−Zr−B−PEG(800) amorphous alloy catalyst has been prepared by chemical reduction and showed excellent performance in the chemoselective hydrogenation of BA to CCA. The agglomeration in the pure Ni−B amorphous alloy 2270

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Article

(12) Sun, C. X.; Wu, Z. J.; Mao, Y. Z.; Yin, X. Q.; Ma, L. Y.; Wang, D. H.; Zhang, M. H. A Highly active Pd on Ni-B bimetallic catalyst for liquid-phase hydrodechlorination of 4-chlorophenol under mild conditions. Catal. Lett. 2011, 141, 792. (13) Liu, H.; Deng, J.; Li, W. Synthesis of nickel nanoparticles supported on boehmite for selective hydrogenation of p-nitrophenol and p-chloronitrobenzene. Catal. Lett. 2010, 137, 261. (14) Li, H.; Zhang, D. Q.; Li, G. S.; Xu, Y.; Lu, Y. F.; Li, H. X. Mesoporous Ni-B amorphous alloy microspheres with tunable chamber structure and enhanced hydrogenation activity. Chem. Commun. 2010, 46, 791. (15) Chen, Y. Z.; Liaw, B. J.; Chiang, S. J. Selective hydrogenation of citral over amorphous NiB and CoB nano-catalysts. Appl. Catal., A 2005, 284, 97. (16) Li, H. X.; Wu, Y. D.; Zhang, J.; Dai, W. L.; Qiao, M. H. Liquid phase acetonitrile hydrogenation to ethylamine over a highly active and selective Ni-Co-B amorphous alloy catalyst. Appl. Catal., A 2004, 275, 199. (17) Möbus, K.; Wolf, D.; Benischke, H.; Dittmeier, U.; Simon, K.; Packruhn, U.; Jantke, R.; Weidlich, S.; Weber, C.; Chen, B. Hydrogenation of aromatic nitrogroups with precious metal powder catalysts: influence of modifier on selectivity and activity. Top. Catal. 2010, 53, 1126. (18) Zhou, G. B.; Liu, J. L.; Tan, X. H.; Pei, Y.; Qiao, M. H.; Fan, K. N.; Zong, B. N. Effect of support acidity on liquid-phase hydrogenation of benzene to cyclohexene over Ru-B/ZrO2 catalysts. Ind. Eng. Chem. Res. 2012, 51, 12205. (19) Okamoto, M.; Hirao, T.; Yamaai, T. Polymers as novel modifiers for supported metal catalyst in hydrogenation of benzaldehydes. J. Catal. 2010, 276, 423. (20) Zhang, S. Y.; Liu, Q. H.; Shen, M.; Hu, B. W.; Chen, Q.; Li, H. X.; Amoureuxc, J. P. A facile route for preparing a mesoporous palladium coordination polymer as a recyclable heterogeneous catalyst. Dalton Trans. 2012, 41, 4692. (21) Liaw, B. J.; Chiang, S. J.; Chen, S. W.; Chen, Y. Z. Preparation and catalysis of amorphous CoNiB and polymer-stabilized CoNiB catalysts for hydrogenation of unsaturated aldehydes. Appl. Catal., A 2008, 346, 179. (22) Bai, G. Y.; Zhao, Z.; Niu, L. B.; Dong, H. X.; Qiu, M. D.; Li, F.; Chen, Q. Z.; Chen, G. F. Effect of polymers and alkaline earth metals on the catalytic performance of Ni-B amorphous alloy in benzophenone hydrogenation. Catal. Commun. 2012, 23, 34. (23) Kaur, P.; Hupp, J. T.; Nguyen, S. T. Porous organic polymers in catalysis: opportunities and challenges. ACS Catal. 2011, 1, 819. (24) Jiang, Z. F.; Xie, J. M.; Jiang, D. L.; Wei, X. J.; Chen, M. Modifiers-assisted formation of nickel nanoparticles and their catalytic application to p-nitrophenol reduction. CrystEngComm 2013, 15, 560. (25) Shinkai, H.; Nishikawa, M.; Sato, Y.; Toi, K.; Kumashiro, I.; Seto, Y.; Fukuma, M.; Dan, K.; Toyoshima, S. N-(Cyclohexylcarbony1)-D-phenylalanines and related compounds. A new class of oral hypoglycemic agents. 2. J. Med. Chem. 1989, 32, 1436. (26) Moore, B. S.; Cho, H.; Casati, R.; Kennedy, E.; Reynolds, K. A.; Mocek, U.; Beale, J. M.; Floss, H. G. Biosynthetic studies on ansatrienin A. Formation of the cyclohexanecarboxylic acid moiety. J. Am. Chem. Soc. 1993, 115, 5254. (27) Temkin, M. I.; Konyukhov, V. Y.; Kul’kova, N. V. Kinetics of liquid phase hydrogenation of benzoic acid. J. Res. Inst. Catal. 1980, 28, 363. (28) Zong, B. N.; Zhang, X. X.; Qiao, M. H. Integration of methanation into the hydrogenation process of benzoic acid. AIChE J. 2009, 55, 192. (29) Wang, H. J.; Zhao, F. Y. Catalytic ring hydrogenation of benzoic acid with supported transition metal catalysts in scCO2. Int. J. Mol. Sci. 2007, 8, 628. (30) Raja, R.; Khimyak, T.; Thomas, J. M.; Hermans, S.; Johnson, B. F. Single-step, highly active, and highly selective nanoparticle catalysts for the hydrogenation of key organic compounds. Angew. Chem., Int. Ed. 2001, 40, 4638.

(31) Thomas, J. M.; Johnson, B. F.; Raja, R.; Sankar, G.; Midgley, P. A. High-performance nanocatalysts for single-step hydrogenations. Acc. Chem. Res. 2003, 36, 20. (32) Guo, Z. Q.; Hu, L.; Yu, H. H.; Cao, X. Q.; Gu, H. W. Controlled hydrogenation of aromatic compounds by platinum nanowire catalysts. RSC Adv. 2012, 2, 3477. (33) Zhang, X. X.; Zong, B. N.; Qiao, M. H. Reactivation of spent Pd/AC catalyst by supercritical CO2 fluid extraction. AIChE J. 2009, 55, 2382. (34) Pojer, P. M. “Deuterated” Raney nickel: deuteration (reduction) of alkenes, carbonyl compounds and aromatic rings. Proton-deuterium exchange of “activated” aliphatic and aromatic ring hydrogens. Tetrahedron Lett. 1984, 25, 2507. (35) Lei, H.; Song, Z.; Tan, D. L.; Bao, X. H.; Mu, X. H.; Zong, B. N.; Min, E. Z. Preparation of novel Raney-Ni catalysts and characterization by XRD, SEM and XPS. Appl. Catal., A 2001, 214, 69. (36) Gual, A.; Godard, C.; Castillón, S.; Claver, C. Soluble transitionmetal nanoparticles-catalysed hydrogenation of arenes. Dalton Trans. 2010, 39, 11499. (37) Wang, Y.; Yao, J.; Li, H. R.; Su, D. S.; Antonietti, M. Highly selective hydrogenation of phenol and derivatives over a Pd@Carbon nitride catalyst in aqueous media. J. Am. Chem. Soc. 2011, 133, 2362. (38) Stanislaus, A.; Cooper, B. H. Aromatic hydrogenation catalysis: a review. Catal. Rev.Sci. Eng. 1994, 36, 75. (39) Anderson, J. A.; McKenna, F. M.; Linares-Solano, A.; Wells, R. P. K. Use of water as a solvent in directing hydrogenation reactions of aromatic acids over Pd/carbon nanofibre catalysts. Catal. Lett. 2007, 119, 16. (40) Wang, W. Y.; Yang, Y. Q.; Luo, H. A.; Peng, H. Z.; Wang, F. Effect of La on Ni-W-B amorphous catalysts in hydrodeoxygenation of phenol. Ind. Eng. Chem. Res. 2011, 50, 10936. (41) Zhu, Z. H.; Ma, J. Q.; Xu, L.; Xu, L.; Li, H. X.; Li, H. Facile synthesis of Co-B amorphous alloy in uniform spherical nanoparticles with enhanced catalytic properties. ACS Catal. 2012, 2, 2119. (42) Ma, Y. F.; Li, W.; Zhang, M. H.; Zhou, Y.; Tao, K. Y. Preparation and catalytic properties of amorphous alloys in hydrogenation of sulfolene. Appl. Catal., A 2003, 243, 215. (43) Wang, W. Y.; Yang, Y. Q.; Bao, J. G.; Luo, H. A. Characterization and catalytic properties of Ni-Mo-B amorphous catalysts for phenol hydrodeoxygenation. Catal. Commun. 2009, 11, 100. (44) Guo, J.; Hou, Y. J.; Yang, C. H.; Wang, Y. Q.; Wang, L. N. Effects of nickel ethylenediamine complex on the preparation of Ni-B amorphous alloy catalyst with ultrasonic assistance. Mater. Lett. 2012, 67, 151. (45) Chen, X.; Li, M.; Guan, J.; Wang, X.; Williams, C. T.; Liang, C. Nickel-silicon intermetallics with enhanced selectivity in hydrogenation reactions of cinnamaldehyde and phenylacetylene. Ind. Eng. Chem. Res. 2012, 51, 3604. (46) Meng, X.; Cheng, H.; Fujita, S.; Hao, Y.; Shang, Y.; Yu, Y.; Cai, S.; Zhao, F.; Arai, M. Selective hydrogenation of chloronitrobenzene to chloroaniline in supercritical carbon dioxide over Ni/TiO2: significance of molecular interactions. J. Catal. 2010, 269, 131. (47) Joseph Antony Raj, K.; Prakash, M. G.; Mahalakshmy, R.; Elangovana, T.; Viswanathan, B. Selective hydrogenation of acetophenone over nickel supported on titania. Catal. Sci. Technol. 2012, 2, 1429. (48) Anderson, J. A.; Athawale, A.; Imrie, F. E.; McKenna, F. M.; McCue, A.; Molyneux, D.; Power, K.; Shand, M.; Wells, R. P. K. Aqueous phase hydrogenation of substituted phenyls over carbon nanofibre and activated carbon supported Pd. J. Catal. 2010, 270, 9. (49) Malyala, R. V.; Rode, C. V.; Arai, M.; Hegde, S. G.; Chaudhari, R. V. Activity, selectivity and stability of Ni and bimetallic Ni-Pt supported on zeolite Y catalysts for hydrogenation of acetophenone and its substituted derivatives. Appl. Catal., A 2000, 193, 71. (50) Hájek, J.; Kumar, N.; Mäki-Arvela, P.; Salmi, T.; Murzin, D. Y. Selective hydrogenation of cinnamaldehyde over Ru/Y zeolite. J. Mol. Catal. A: Chem. 2004, 217, 145. 2271

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Article

(51) Liu, R.; Yu, Y.; Yoshida, K.; Li, G.; Jiang, H.; Zhang, M.; Zhao, F.; Fujita, S.; Arai, M. Physically and chemically mixed TiO2-supported Pd and Au catalysts: unexpected synergistic effects on selective hydrogenation of citral in supercritical CO2. J. Catal. 2010, 269, 191. (52) Rajadhyaksha, R. A.; Karwa, S. L. Solvent effects in catalytic hydrogenation. Chem. Eng. Sci. 1986, 41, 1765. (53) Ning, J.; Xu, J.; Liu, J.; Miao, H.; Ma, H.; Chen, C.; Li, X.; Zhou, L.; Yu, W. A remarkable promoting effect of water addition on selective hydrogenation of p-chloronitrobenzene in ethanol. Catal. Commun. 2007, 8, 1763. (54) Sadeghmoghaddam, E.; Gu, H.; Shon, Y. Pd Nanoparticlecatalyzed isomerization vs hydrogenation of allyl alcohol: solventdependent regioselectivity. ACS Catal. 2012, 2, 1838. (55) Yan, N.; Xiao, C.; Kou, Y. Transition metal nanoparticle catalysis in green solvents. Coord. Chem. Rev. 2010, 254, 1179. (56) Zhang, Y.; Lavin, J. M.; Shimizu, K. D. Solvent programmable polymers based on restricted rotation. J. Am. Chem. Soc. 2009, 131, 12062. (57) Wang, X. X.; Huang, M. Y.; Jiang, Y. Y. Hydrogenation of aromatic compounds catalyzed by platinum complex of starch-poly-γaminopropylsiloxane. React. Polym. 1992, 18, 1.

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