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Title: Hydrodeoxygenation of p -Cresol over Pt/Al 2 O 3 Catalyst Promoted by ZrO 2 , CeO 2 , and CeO 2 –ZrO 2

Abstract

ZrO 2-Al 2O 3 and CeO 2-Al 2O 3 were prepared by a co-precipitation method and selected as supports for Pt catalysts. The effects of CeO 2 and ZrO 2 on the surface area and Brønsted acidity of Pt/Al 2O 3 were studied. In the hydrodeoxygenation (HDO) of p-cresol, the addition of ZrO 2 promoted the direct deoxygenation activity on Pt/ZrOO 2-Al 2O 3 via Caromatic-O bond scission without benzene ring saturation. Pt/CeOO 2-Al 2O 3 exhibited higher deoxygenation extent than Pt/Al 2O 3 due to the fact that Brønsted acid sites on the catalyst surface favored the adsorption of p-cresol. With the advantages of CeO 2 and ZrO 2 taken into consideration, CeO 2-ZrOO 2-Al 2O 3 was prepared, leading to the highest HDO activity of Pt/CeO 2-ZrOO 2-Al 2O 3. The deoxygenation extent for Pt/CeO 2-ZrOO 2-Al 2O 3 was 48.4% and 14.5% higher than that for Pt/ZrO2O 2-Al 2O 3 and Pt/CeOO 2-Al 2O 3, respectively.

Authors:
 [1];  [2];  [2];  [2];  [2];  [3]
  1. Xiangtan Univ. (China). School of Chemical Engineering; Washington State Univ., Pullman, WA (United States). Voiland School of Chemical Engineering and Bioengineering
  2. Xiangtan Univ. (China). School of Chemical Engineering
  3. Washington State Univ., Pullman, WA (United States). Voiland School of Chemical Engineering and Bioengineering; Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1333447
Report Number(s):
PNNL-SA-119534
Journal ID: ISSN 0888-5885; KC0302010
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Industrial and Engineering Chemistry Research; Journal Volume: 55; Journal Issue: 28
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Wang, Weiyan, Wu, Kui, Liu, Pengli, Li, Lu, Yang, Yunquan, and Wang, Yong. Hydrodeoxygenation of p -Cresol over Pt/Al 2 O 3 Catalyst Promoted by ZrO 2 , CeO 2 , and CeO 2 –ZrO 2. United States: N. p., 2016. Web. doi:10.1021/acs.iecr.6b00515.
Wang, Weiyan, Wu, Kui, Liu, Pengli, Li, Lu, Yang, Yunquan, & Wang, Yong. Hydrodeoxygenation of p -Cresol over Pt/Al 2 O 3 Catalyst Promoted by ZrO 2 , CeO 2 , and CeO 2 –ZrO 2. United States. doi:10.1021/acs.iecr.6b00515.
Wang, Weiyan, Wu, Kui, Liu, Pengli, Li, Lu, Yang, Yunquan, and Wang, Yong. 2016. "Hydrodeoxygenation of p -Cresol over Pt/Al 2 O 3 Catalyst Promoted by ZrO 2 , CeO 2 , and CeO 2 –ZrO 2". United States. doi:10.1021/acs.iecr.6b00515.
@article{osti_1333447,
title = {Hydrodeoxygenation of p -Cresol over Pt/Al 2 O 3 Catalyst Promoted by ZrO 2 , CeO 2 , and CeO 2 –ZrO 2},
author = {Wang, Weiyan and Wu, Kui and Liu, Pengli and Li, Lu and Yang, Yunquan and Wang, Yong},
abstractNote = {ZrO2-Al2O3 and CeO2-Al2O3 were prepared by a co-precipitation method and selected as supports for Pt catalysts. The effects of CeO2 and ZrO2 on the surface area and Brønsted acidity of Pt/Al2O3 were studied. In the hydrodeoxygenation (HDO) of p-cresol, the addition of ZrO2 promoted the direct deoxygenation activity on Pt/ZrOO2-Al2O3 via Caromatic-O bond scission without benzene ring saturation. Pt/CeOO2-Al2O3 exhibited higher deoxygenation extent than Pt/Al2O3 due to the fact that Brønsted acid sites on the catalyst surface favored the adsorption of p-cresol. With the advantages of CeO2 and ZrO2 taken into consideration, CeO2-ZrOO2-Al2O3 was prepared, leading to the highest HDO activity of Pt/CeO2-ZrOO2-Al2O3. The deoxygenation extent for Pt/CeO2-ZrOO2-Al2O3 was 48.4% and 14.5% higher than that for Pt/ZrO2O2-Al2O3 and Pt/CeOO2-Al2O3, respectively.},
doi = {10.1021/acs.iecr.6b00515},
journal = {Industrial and Engineering Chemistry Research},
number = 28,
volume = 55,
place = {United States},
year = 2016,
month = 7
}
  • Supported bimetallic catalysts consisting of a noble metal (e.g., Pt) and an oxophilic metal (e.g., Mo) have received considerable attention for the hydrodeoxygenation of oxygenated aromatic compounds produced from biomass fast pyrolysis. Here, we report that PtMo can catalyze m-cresol deoxygenation via a pathway involving an initial tautomerization step. In contrast, the dominant mechanism on monometallic Pt/Al 2O 3 was found to be sequential Pt-catalyzed ring hydrogenation followed by dehydration on the support. Bimetallic Pt 10Mo 1 and Pt 1Mo 1 catalysts were found to produce the completely hydrogenated and deoxygenated product, methylcyclohexane (MCH), with much higher yields than monometallicmore » Pt catalysts with comparable metal loadings and surface areas. Over an inert carbon support, MCH formation was found to be slow over monometallic Pt catalysts, while deoxygenation was significant for PtMo catalysts even in the absence of an acidic support material. Experimental studies of m-cresol deoxygenation together with density functional theory calculations indicated that Mo sites on the PtMo bimetallic surface dramatically lower the barrier for m-cresol tautomerization and subsequent deoxygenation. The accessibility of this pathway arises from the increased interaction between the oxygen of m-cresol and the Mo sites in the Pt surface. This interaction significantly alters the configuration of the precursor and transition states for tautomerization. Lastly, a suite of catalyst characterization techniques including X-ray absorption spectroscopy (XAS) and temperature-programmed reduction (TPR) indicate that Mo was present in a reduced state on the bimetallic surface under conditions relevant for reaction. Overall, these results suggest that the use of bifunctional metal catalysts can result in new reaction pathways that are unfavorable on monometallic noble metal catalysts.« less
  • Fe based catalysts are promising for hydrodeoxygenation (HDO) of lignin derived phenolics due to their high selectivity for aromatics. In this work, the reaction mechanism of m-cresol HDO on Fe catalysts and the kinetic consequence with Pd addition were elucidated by examining the effect of H2, H2O and m-cresol pressures on toluene formation rate on Fe and PdFe catalysts. A direct CO bond cleavage mechanism is proposed for HDO catalysis on both Fe and PdFe catalysts, while Pd provides a facilitated reaction pathway at the PdFe interface and therefore promotes the catalysis on Fe without changing the high selectivity towardsmore » aromatics.« less
  • Simultaneous hydrodenitrogenation (HDN) and hydrodeoxygenation (HDO) is studied with indole/m-cresol conversions over a sulfided CoMo HDS catalyst. The mutual inhibition of indole (and indoline) on HDO and of n-cresol on HDN is established. As with HDS/HDO reported in paper II, the HDN/HDO reactions appear to proceed on the same site. The relative reactivity of the indole and cresol, as well as an HDN intermediate, o-ethyl aniline, is m-cresol >> o-ethyl aniline > indole (indoline). Under the conditions of our study (P/sub H/sub 2// = 69 atm, T = 250-350/sup 0/C), the indole-indoline hydrogenation equilibrium is essentially achieved. The pure componentmore » conversion kinetics are adequately described by a two-site Longmuir-Hinshelwood form, the rate and binding constant values indicating correctly the relative reactivity and mutual inhibition magnitudes, thus confirming that simultaneous HDO and HDN proceed on the same surface sites. At the lower HDN temperatures, the intermediate o-ethyl aniline is converted to ethylbenzene, then ethylcyclohexane, while at or above 300/sup 0/C some ring hydrogenation to o-amino ethylcyclohexane precedes HDN. Hydrogenation, HDO, and HDN activities are completely recovered by 400/sup 0/C regeneration, in contrast to activity loss noted in paper II for simultaneous HDS/HDO.« less
  • Interactions during simultaneous catalytic hydrodesulfurization (HDS) and hydrodeoxygenation (HDO) are studied with (benzothiophene, dibenzothiophene)/(m-cresol) conversions over CoMo HDS catalysts. The mutual inhibition of cresol on HDS and of the benzothiophenes on HDO is shown. The reaction patterns observed are rationalized by competition between oxygenate and sulfur heterocycle for the catalyst sites. A Langmuir-Hinshelwood kinetic form provides a useful rate equation for simultaneous HDO-HDS operation. The relative reactivity in equimolar feed experiments is benzothiophene > dibenzothiophene > m-cresol. The modest reactivity of m-cresol, coupled with its inhibitory influence of HDS of benzothiophene and dibenzothiophene, has clear implications for HDS in coalmore » liquids processing and HDN in shale oil conversions. In the mixed feeds of the present paper (II), as for the pure oxigenate feeds studied previously (I), no evidence is obtained that ring saturation of cresol is required prior to HDO.« less
  • Oxidative coupling of methane (OCM) to higher hydrocarbons over Sr-promoted La{sub 2}O{sub 3} supported on commercial low surface area porous catalyst carriers at 800 and 850 C and a space velocity of 102,000 cm{sup 3}/g{center_dot}h has been thoroughly investigated. Effects of support, catalyst particle size, linear gas velocity, Sr/La ratio, CH{sub 4}/O{sub 2} ratio in the feed, and catalyst dilution by inert solid particles on the conversion, yield, or selectivity and product ratios (C{sub 2}H{sub 4}/C{sub 2}H{sub 6} and CO/CO{sub 2}) in the OCM process have been studied. The catalysts have been characterized for their basicity, acidity, and oxygen chemisorptionmore » by the TPD of CO{sub 2}, ammonia, and oxygen, respectively, from 50 to 950 C and also characterized for their surface area. The supported catalysts showed better performance than the unsupported one. The best OCM results (obtained over Sr-La{sub 2}O{sub 3}/SA-5205 with a Sr/La ratio of 0.3 at a space velocity of 102,000 cm{sup 3}/g{center_dot}h) are 30.1% CH{sub 4} conversion with 65.6% selectivity for C{sub 2+} (or 19.7% C{sub 2+}-yield) at 850 C (CH{sub 4}/O{sub 2} = 16.0). The basicity is strongly influenced by the Sr/La ratio; the supported catalysts showed the best performance for their Sr/La ratio of about 0.3. The methane/O{sub 2} ratio also showed a strong influence for their Sr/La ratio of about 0.3. The methane/O{sub 2} ratio also showed a strong influence on the OCM process. However, the influence of linear gas velocity and particle size is found to be small; it results mainly from the temperature gradient in the catalyst. The catalyst dilution has beneficial effects for achieving a higher C{sub 2}H{sub 4}/C{sub 2}H{sub 6} ratio and also for reducing the hazardous nature of the OCM process because of the coupling of the exothermic oxidative conversion reactions and the endothermic thermal cracking reactions and also due to the increased heat transfer area.« less