AlF3-Supported Ruthenium Catalysts for the

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Preparation of Al2O3/AlF3-Supported Ru Catalysts for Hydrogenolysis of Biodiesel-Derived Crude Glycerol Tamer Samir Ahmed, Omar Y AbdElAziz, and George Willard Roberts Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.6b00500 • Publication Date (Web): 29 Apr 2016 Downloaded from http://pubs.acs.org on April 30, 2016

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Industrial & Engineering Chemistry Research

Preparation of Al2O3/AlF3-Supported Ru Catalysts for Hydrogenolysis of Biodiesel-Derived Crude Glycerol Tamer S. Ahmeda,b,*, Omar Y. Abdelazizb,c, and George W. Robertsa,• a

Department of Chemical and Biomolecular Engineering, North Carolina State University, Box # 7905, Raleigh, North Carolina 27695-7905, USA b c

Chemical Engineering Department, Faculty of Engineering, Cairo University, Giza 12613, Egypt

Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden

ABSTRACT: Hydrogenolysis of biodiesel-derived glycerol to value-added chemicals has emerged as an innovative approach to biowaste valorization for a more sustainable society. In the present work, Ru catalysts on Al2O3/AlF3 supports with different AlF3 content were prepared by the aqueous incipient wetness method and tested in the reaction of glycerol hydrogenolysis for the first time. The prepared catalysts were characterized by neutron activation analysis, N2 physisorption, and H2 chemisorption techniques. The catalytic hydrogenation of crude glycerol was performed at 473 K, hydrogen pressure of 4.0 MPa, and 5 wt% glycerol aqueous solution for 4 h with comprehensive characterization of liquid and gas phase products. Texture, structure, and activity of the prepared catalysts were significantly affected by the fluoridation. In order to understand more the mechanism of possible reactions for glycerol hydrogenolysis, the effect of pH and individual hydrogenolysis of most of the products of the glycerol reaction were investigated.

KEYWORDS: Glycerol hydrogenolysis; Ruthenium; Catalysts; Biodiesel; Gamma alumina; Fluorinated alumina

*

Corresponding author. Tel.: +20-114-292-4407. E-mail: [email protected]

•

In memory of Prof. George W. Roberts The authors declare no competing ﬁnancial interest.

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1. INTRODUCTION The hydrogenolysis of higher polyols such as sorbitol, xylitol, and glycerol has been examined over the past decades in literature

1–3

. Besides, the interest in glycerol hydrogenolysis

has surpassed the others recently 4–9. One reason is the rapid growth in biodiesel production as a result of the dramatic increase in the price of crude oil, coupled with increased environmental concerns. Glycerol is the primary byproduct resulting from biodiesel and it is considered a highly fascinating molecule for the synthesis of a wide variety of high value chemical intermediates, withal being a platform chemical for the production of biofuel additives 10. However, the existing glycerol supply and demand markets are tight and recent increases in glycerol production from biodiesel refining have created a glut in the glycerol market. Consequently, the price of glycerol has fallen significantly and biodiesel refiners are faced with limited options for managing the glycerol byproduct, which has essentially become a waste stream

11

. Biodiesel production has

been continuously increasing during the previous years and it is predicted to increase further in the future. Bearing in mind that the glycerin will probably proceed to be available at a low cost for the predicted future, which eventually encourages the continued research in using this biowaste resource for creating novel and innovative applications 12. Thus, to ensure the economic efficiency of the biodiesel manufacturing processes, new solutions for the effective utilization of the glycerol byproduct streams must be found. Aqueous glycerol hydrogenolysis was investigated on various catalyst/support combinations. Examples include Ru/C

4,5,7,13–17

, Ru/C with solid acids

18

, Ru/SiO2

7,14,19

,

Ru/Al2O3 7,13,14, Ru/TiO2 14,20,21, Ru/ZrO2 13,19, Ru/ZnO 22, Ru/NaY 14 Ru/hydrotalcite-like or CaZn modified hydrotalcite 23, Pt/C 7,15–17, Pt/SiO2 7, Pt/Al2O3 7, Pt/ZnO 22 , Pt/CaCO3 24, Pt/Nb2O5Al2O3 25, Pt/amorphous silica–alumina 26, Pd/C

7,15,17,27

2

, Pd/SiO2 7, Pd/Al2O3 7, Pd/ZnO 22, Rh/C


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7,17,27

, Rh/SiO2 7, Rh/Al2O3 27

CuO/ZnO

HZSM-5, Hβ zeolites 38

hectorites

32

, CuO/SiO2

35

7,27

, Re, Mo and W enhanced Rh/SiO2

, Cu/MgO

,

33

, Cu/Al2O3

Cu-ZnO-Al2O3

36

34

28

, Cu/SiO2

29

, Cu/ZnO

30,31

,

, Cu/different zeolites such as HY, 13X,

, Cu/Cu-Mg-Al hydrotalcite

, Cu/ZnO/MOx (MOx =Al2O3, TiO2, and ZrO2)

39

37

Cu-fly ash

, Cu/delaminated 40

, Rh promoted

Cu/Mgx-Aly-Oz 41, Co/MgO 42, Ir/C 43, Ir-ReOx/SiO2 44, Ir-ReOx/SiO2 with HZSM-5 zeolite as a co-catalyst Ni/SiO2

50

45

, Raney Cu

, Ni2P/SiO2

49

15

, Raney Ni

15,46,47

, Ni/Al2O3

, Ni-Ce/activated carbon

51

48

, Ni/SiO2

, Ni–Cu/Al2O3

52

49

, Ce promoted metallic

, copper chromite complex

with various promoters 53, Ru-Pt/C 6, Ru-Au/C 6, Ru-Cu/SiO2 29, Ru-Re/C 54, Ru-Re/SiO2 55, PdCu/solid-base catalysts prepared via layered double hydroxides precursors 56, Pt-WO3-TiO2/SiO2 57

, and Pt-Sn/SiO2 58. In the light of these premises, it can be noted that the cleavage of carbon−carbon (C−C)

bonds by transition metals is of remarkable interest within the glycerol hydrogenolysis reaction, towards the necessary transformation to produce industrially essential chemicals and biofuels from conventional natural resources like petroleum and biomass. Among different transition metals adopted, Ruthenium, in particular, is known to be one of the best catalysts for glycerol hydrogenolysis 54. Its activity of hydrogenolysis compared to other supported catalysts generally follows the order 59 Ru ≈ Cu ≈ Ni > Pt > Pd Additionally, Ru is not considerably as sensitive to sulfur poising as other metals and its catalytic activity and selectivity towards glycerol hydrogenolysis products depends on the catalyst, support, promoters/co-catalysts, and reaction conditions

22

. For industrial applications, in

general, easily recyclable/removable heterogeneous catalysts are favored. Indeed, the transition metal complexes are exploited in numerous chemical processes related to the glycerol

3



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valorization chemistry; however, the environmental issues provoked from their utilization remains a question. Though, it is the catalyst cost per kg of product that really counts in the end, influencing the choice of such rare earth metal for these kind of reactions from a practical perspective. Going forward, glycerol hydrogenolysis over Ru-supported catalysts usually results in many products such as propanediols, ethylene glycol, methanol, ethanol, propanols, and gaseous hydrocarbons. Since Ru promotes C-C cleavage, it usually results in substantial amount of gaseous products as well, such as methane 54. In this paper, Ru catalysts on AlF3-Al2O3 supports with different AlF3 content were prepared and the hydrogenolysis of biodiesel-derived crude glycerol over them was performed. The effect of AlF3 content was covered. Also, to understand the mechanism of reaction, the individual hydrogenolysis of some of the glycerol reaction products was investigated. To the best of our knowledge, no extensive research work on the Ru/AlF3-Al2O3 catalysts has been reported so far for crude glycerol hydrogenolysis to useful liquid-phase and gas-phase products.

2. EXPERIMENTAL SECTION Four different Ru-supported catalysts were prepared by the aqueous incipient wetness technique. The first one used a pure γ-Al2O3 (Saint-Gobain NorPro, supplied as 1/16 in extrudates) support pre-heated at 500 ºC for 3 hours, under helium flow. The other three employed AlF3-Al2O3 supports with different AlF3 content. The AlF3-Al2O3 supports were prepared by the fluoridation of γ-Al2O3 extrudates with trifluoromethane (SynQuest Labs, Inc.). The extrudates were placed between two layers of quartz wool in a quartz tube at 500 ºC in a tube furnace, while passing 40% trifluoromethane/helium mixture 60. The extent of fluoridation was controlled using the time of exposure of the extrudates to the trifluoromethane (17, 69, and 99 min for the three supports prepared).

4


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The extrudates were wet grinded to a particle size less than 75 µm using a synthetic sapphire mortar. The resulted powder was dried in an oven overnight at 135 ºC before impregnation with RuCl3 solution (Sigma-Aldrich). After impregnation, the powder was dried at room temperature for an hour before being dried in an oven at 110 ºC for 24 hr. The scanning electron microscope (SEM) images for the four catalysts prepared before reduction are represented in Figure 1. As depicted, Cat A represents the catalyst utilizing pure γ-Al2O3 support, while the support of the three other catalysts: Cat B, Cat C, and Cat D incorporates about 17.5, 58.9, and 79.6 wt% AlF3, respectively; the Ru content for these catalysts is about 4.3±0.1 wt% in average. The powder was reduced with H2 at 327 ºC for 3 hours (ramp rate = 10 ºC/min, H2 flow = 550 scc/min) and cooled down, under a flow of helium. The cooled down powder was kept in ammonia solution (10% w/v) overnight to remove the residual chlorine from the catalyst61 then washed at least three times with deionized water. Figure 1 Comes Here The AlF3 content of the supports was determined by both the weight gain due to the conversion of Al2O3 to AlF3 and by Neutron Activation Analysis (NAA) for fluorine content (Elemental Analysis, Inc.). The average of both measurements has been adopted. BET surface area, pore volume, and pore diameter were measured by nitrogen physisorption at its boiling point using a Tristar 3000 analyzer (Micromeritics, Inc.). Ruthenium loading of the catalysts was determined by NAA (Elemental Analysis, Inc.). Finally, hydrogen chemisorption was conducted using an ASAP 2020 analyzer (Micromeritics, Inc.). The hydrogenolysis experiments were carried out in a 300 mL stainless steel autoclave (Autoclave Engineers) equipped with a magnetically-driven agitator (Autoclave Engineers). A Dispersimax turbine-type impeller was mounted on the shaft of the agitator. The reactor is

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equipped with a dip tube, a purge valve, rupture disc, pressure transducer, and a thermocouple placed in a thermo-well. The experiments were conducted at constant total pressure since hydrogen was fed continuously to the reactor to make up for the consumption of hydrogen in the reactions. Unless otherwise is mentioned, the experiments standard conditions were: 40 bar total pressure, 200 ºC, 5 wt% initial aqueous solution, 150 mL feed volume, 0.3 g catalyst, 1500 rpm stirring speed, and 4 h reaction time. In a typical experiment, the catalyst powder is placed in the reactor then the reactor is sealed and purged with hydrogen (99.999%; Airgas) five times. The catalyst is reduced another time in-situ with hydrogen at 260 ºC for one hour and then the reactor is cooled down to 150 ºC. The hydrogen pressure is adjusted to about 10 bar and the feed solution is injected using an HPLC pump (Alltech 301 HPLC pump). Finally, the reactor is heated up to the desired temperature and the total pressure is adjusted. At the end of the reaction time, the hydrogen feed is stopped and the vessel is quenched down quickly to 21 ºC using water/ice bath. The gas is collected in a 250 mL gas bulb and the liquid is collected using the dip tube of the reactor. Finally, the liquid is filtered and diluted down with deionized water to 5X dilution before analysis. The analysis of the liquid sample was performed using a GC equipped with a flame ionization detector and a thermal conductivity detector using Restek MTX-Wax column (0.53 mm internal diameter, 60 m length, 1 µm phase thickness). As for the gas samples, the analysis was carried out using another GC equipped with a helium ionization detector and thermal conductivity detector using Restek ShinCarbon ST 80/100 packed column (1/8 in outside diameter, 2 m length). Products were identified using an HP5890 GC connected to an HP5972 mass selective detector (Edison Analytical Laboratories, Inc.). Liquid products identified were:

6


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1, 2-propanediol (1,2-PD), ethylene glycol (EG), methanol (MeOH), ethanol (EtOH), n-propanol (n-PrOH), i-propanol (i-PrOH), and traces of acetone (AC). Gas products identified were: methane, ethane, propane, and carbon dioxide.

3. RESULTS AND DISCUSSION 3.1. Catalyst Characterization. Four catalysts were prepared to be used in the hydrogenolysis experiments with different AlF3/Al2O3 ratios of the support. Cat A used a pure γAl2O3 support, while the support of the other three catalysts: Cat B, Cat C, and Cat D had about 17.5, 58.9, and 79.6 wt% AlF3, respectively. McVicker et al.

60

reported the acidity of

Al2O3/AlF3 supports with different AlF3 content from 0-100% prepared with the same procedure adopted in the current work. The values reported showed increase in acidity of the supports with increasing AlF3 content, especially the strong acidic sites. Table 1 summarizes the prepared four catalysts and their characteristics. The average Ru content for these catalysts was about 4.3±0.1 wt%. Table 1 Comes Here The analysis of the catalysts shows that the addition of AlF3 changed the texture structure significantly (Figure 1). The particles size tends to increase with increasing the AlF3/Al2O3 ratio. In addition, with increasing the AlF3 content from 0 to 79.6 wt%, the BET surface area and the total pore volume of the catalysts obviously decreased monotonically from 227 to 38 m2/g and from 0.67 to 0.14 cm3/g, respectively. On the other hand, there is an observable increase in the average pore diameter with increasing the AlF3 content of the support. Both observations agree well with what reported by McVicker et al.60.

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Hydrogen chemisorption measurements have been performed in order to determine the percentage of the exposed Ru atoms. The analysis shows that as the AlF3 content in the support increases, the metal dispersion significantly increases initially until it reaches a maximum value near the 17.5 wt% AlF3 catalyst (Cat B). On further increase of the AlF3 content in the support, the metal dispersion decreases, however, with a lower slope (Figure 2). This behaviour may be attributed to conflicting effects of the decrease in the micropores of the support in the same time of increase in the support-particle size with increasing the AlF3 content. Figure 2 Comes Here 3.2. Hydrogenolysis of Glycerol. Table 2 presents the experimental results of glycerol hydrogenolysis using the prepared four catalysts plus a blank reaction without any catalyst. The values for each catalyst in Table 2 are the average of two experiments. The repeatability of the results is within ±5-10%. Carbon material balance at the end of the reaction time, conversion, and selectivity were calculated using Eqs. (1), (2), and (3), respectively.

C − Material Balance ( % ) =

Conversion ( % ) =

C -based moles of ( products + unreacted feed )

× 100

C -based moles of initial feed − C -based moles of unreacted feed

Selectivity of product i ( % ) =

(1)

C -based moles of initial feed

C -based moles of initial feed

C -based moles of product i

× 100

C -based moles of all products

× 100

(2)

(3)

Table 2 Comes Here Experiment #1 was conducted without any catalyst. Conversion less than 1% was encountered and this notably reveals that the presence of catalyst is essentially required for the

8


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hydrogenolysis to proceed. This agrees with what was reported in the literature 16. Experiment #2 was done using Cat A (pure Al2O3 support). At the reaction conditions and with 4 h reaction time, the achieved conversion was about 33%; the main products generated were EG, 1,2-PD, and methane. With fluoridation of the support (experiment #3, #4, and #5), the conversion reached a maximum between AlF3 content 17.5% and 58.9% (Cat B and Cat C). With increasing fluoridation, the conversion declined again. As for selectivity, the same main products observed for Cat A were observed for the other three catalysts. However, there is an observable increase in selectivity towards methane for Cat B. Figure 3 depicts the glycerol conversion and the selectivity of the products identified (EG, 1,2-PD, methane, and other products) for the different catalysts. Figure 3 Comes Here The results achieved here regarding the reaction conversion and the selectivity towards EG and 1,2-PD are found to be quantitatively promising in comparison with other recently published reports utilizing Ru in glycerol hydrogenolysis. For instance, under a reaction pressure of 8 MPa, temperature of 453 K, and 24 h reaction time, Gallegos-Suarez et al.

62

reported the

usage of activated carbon, graphite, carbon nanotubes, and KL-zeolite as Ru-catalyst supports for conducting the reaction. Selectivity values of 14%, 16%, 22%, and 32% towards 1,2-PD and 63%, 32%, 35%, and 48% towards EG were achieved, respectively, for the preceding catalyst complexes. Howbeit, low conversion values were reached, typically of 11%, 26%, 28%, and 7.5%, respectively during the 24 h reaction time. In another recent contribution employing Ru/Al2O3 as the catalyst

63

, 41.7% selectivity towards 1,2-PD was attained with conversion of

32.8%, under 2.5 MPa hydrogen pressure and 473 K reaction temperature. Another study by

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Pavan Kumar et al.

64

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obtained a glycerol conversion of 42% and selectivity towards 1,2-PD

(40%), 1,3-PD (10%), and EG (13%) over nanosized Ru supported on γ-Al2O3. The products detected in the gaseous and liquid streams can be formed via different reaction routes. Ruthenium is known to promote C-C cleavage 54. This can be noticed here in the high selectivity values to EG comparing to 1,2-PD and the substantial amount of gaseous products formed, particularly methane. It can be observed that the ratio of the selectivity towards EG to that towards 1,2-PD increases slightly with fluoridation of the support (Cat B) and then drop down with further fluoridation (Cat C and Cat D) (see Figure 4). It is worth noting that, the slight increase for Cat B may be attributed to the observable increase in its metal dispersion compared to other catalysts with fluorinated supports. Figure 4 Comes Here Ruthenium-based catalysts usually show high performance in aqueous reforming of glycerol (Equation 4)

65,66

. Even though, no CO was detected in all of the current experiments.

This may be attributed to that Ru is also a good methanation catalyst (Equation 5). In addition, ethane and propane can be produced from Fischer-Tropsch like reactions (Equations 6 and 7). Therefore, the produced CO might have been reacted with H2 forming the gaseous alkanes. To investigate this possibility, an experiment using 5% CO in H2 in water (without glycerol) was performed for Cat B, under the same operating conditions. The experiment yielded about 95.4%, 2.1%, and 2.5% selectivity for methane, ethane, and propane, respectively with a conversion near 99.9% for the CO. C3 H 8O3 → 3CO + 4 H 2

(4)

10


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CO + 3H 2 → CH 4 + H 2O

(5)

CO + 5 H 2 → C2 H 6 + 2 H 2O

(6)

CO + 7 H 2 → C3 H 8 + 3H 2O

(7)

Some traces of CO2 were identified in the gaseous products of the experiments presented in Table 2. This can be attributed to different reactions. The first reaction is the water-shift reaction, especially since it is thermodynamically favored at the low temperatures 67, such as that used in the current experiments. The second reaction is the Cannizzaro reaction, where under the hydrogenolysis conditions, CO2 can be formed 16,68. 3.3. Effect of pH. Table 3 shows the effect of alkalinity on the hydrogenolysis of glycerol on Cat B using the same reaction conditions as previous, but using 0.1M NaOH solution as reaction medium. A remarkable change in the selectivity of both 1,2-PD and EG has been observed compared to experiments done in pure water. The presence of NaOH resulted in increasing the selectivity towards 1,2-PD from 17.6% to 31.9% and a decrease in the selectivity towards EG from 45.1% to 23.1%. The decrease in the selectivity of EG particularly is likely due to conversion of a reactive intermediate between ethylene glycol and glyceraldehyde that accordingly eliminates some substance from the glycol route to a degradation product pathway; this agrees well with other tested catalysts under basic conditions

20

increase in the catalyst activity was expected in the basic environment

. On the other hand, an 4,6,16,20

, but there was no

significant change in the conversion recognized in the current experiments. This may be attributed to an insufficient hydroxide concentration at such conditions, especially if it taken into consideration the acidity of the support. Table 3 Comes Here

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3.4. Hydrogenolysis of Liquid Products. In order to understand more the mechanism of the possible reactions for glycerol hydrogenolysis, the individual hydrogenolysis of most of the products of the glycerol reaction was performed. Table 4 summarizes the hydrogenolysis of some individual liquid components that were identified during the hydrogenolysis of crude glycerol. Nonetheless, Figure 5 represents the selectivity to MeOH, EtOH, methane, ethane+propane, and other components produced from each liquid-product hydrogenolysis. The liquid-products hydrogenolysis experiments were conducted using Cat B, under the same reaction conditions adopted for the glycerol hydrogenolysis experiments using 5 wt% feed concentration. Table 4 Comes Here Figure 5 Comes Here The hydrogenolysis of EG yielded mainly MeOH and methane. A possible route is the CC cleavage of EG to MeOH. A combination of C-O cleavage and hydrogenation and/or MeOH reforming, water-shift reaction, and methanation reactions can produce methane. This is illustrated in the hydrogenolysis of MeOH feed experiment, where about 99% selectivity towards methane was observed. Furthermore, the trace of higher alkanes observed suggests the presence of CO as an intermediate to form the higher alkanes via Fischer-Tropsch like reactions (Equations 6 and 7). Moreover, the formation of 1-2-PD during the EG hydrogenolysis is interesting since it suggests the complexity of reactions encountered, which includes recombination reactions. The hydrogenolysis of 1,2-PD yielded mainly hydroxyacetone (acetol), methane, and EtOH. Although the appreciable selectivity towards the formation of hydroxyacetone during the hydrogenolysis of 1,2-PD, no hydroxyacetone was identified during the hydrogenolysis of 12


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glycerol. During glycerol hydrogenolysis, hydroxyacetone is supposed to be formed as an intermediate by the dehydration of glycerol before being hydrogenated quickly to 1,2-PD

15

.

Howbeit, during the 1,2-PD hydrogenolysis, since there is an appreciable amount of 1,2-PD compared to the case of glycerol hydrogenolysis, the equilibrium may favoured the reverse reaction to form hydroxyacetone. Finally, for the hydrogenolysis of lower alcohols, the reactions yielded mainly gaseous alkanes, especially methane (and ethane in case of n-PrOH). The only exception is the hydrogenolysis of i-PrOH, where acetone was the main product.

4. CONCLUSIONS Ru on AlF3-Al2O3 support catalysts with different AlF3 contents were synthesized for hydrogenolysis of biodiesel-derived crude glycerol to value-added products in the context of biowaste valorization. Characterization of the catalysts revealed that the fluoridation had a significant effect on the chemical–physical properties of the catalysts, such as the BET surface area, the dispersion of Ru, and the total pore volume, as well as, the average pore diameter. Hydrogen chemisorption measurements showed that the Ru dispersion reached a maximum at about 23 wt% AlF3. Glycerol hydrogenolysis experiments indicated that the conversion reached its maximum between 17.5 wt% and 58.9 wt% AlF3 content. Besides, the selectivity to the main useful liquid products obtained (EG and 1,2-PD) was found to be affected by the fluoridation. A substantial amount of methane gas was detected due to promoting the C-C cleavage by Ru. The presence of NaOH resulted in increasing the selectivity towards 1,2-PD over EG. Performing the individual hydrogenolysis for most of the products of glycerol reaction enabled a better understanding for the mechanism of glycerol hydrogenolysis possible reactions.

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ACKNOWLEDGMENTS This research was based upon work supported by the STC Program of the National Science Foundation under Agreement No. CHE-9876674. Special thanks to Jonathon R. Harding, PhD candidate at MIT, for helping in the CO/H2 experiments.

DEDICATION This paper is dedicated to the memory of George W. Roberts, Professor Emeritus and Former Department Head of Chemical & Biomolecular Engineering at North Carolina State University.

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Page 20 of 29

TABLES

Table 1. Catalysts Prepared and their Characteristics Catalyst

AlF3

BET

Support

Support

Ru

Metal

Name

(wt%)

support

total pores

average

loading

dispersion

surface

volume

pore

(wt%)

using H2

area

(cm3/g)

diameter

2

Acidity (±25 µmole/g) pKa (1) ≤ - 8.2

≤ - 5.6

≤ - 3.0

(%)

(nm)

(m /g) Cat A

0

227

0.67

10.3

4.3

7.2

325

325

475

Cat B

17.5

182

0.57

10.7

4.3

47.8

275

325

325

Cat C

58.9

80

0.28

11.9

4.4

36.7

125

175

175

Cat D

79.6

38

0.14

12.7

4.2

31.0

75

125

125

(1)

Abstracted from McVicker et al.

60

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Table 2. Glycerol Hydrogenolysis Experiments. Reaction Conditions: 40 bar total pressure, 200 ºC, 5 wt% initial solution, 150 mL feed volume, 0.3 g catalyst, 1500 rpm stirring speed, and 4 h reaction time Selectivity, %

# Catalyst

Name

C-Material balance, %

Conversion, %

Acetone MeOH EtOH i-PrOH n-PrOH 1,2-PD EG CH4 CO2 C2H6

1

No Catalyst

103.6

0.8

2.3

2.4

5.8

1.1

7.6

26.6

44.0 8.5

2

Cat A

94.1

33.0

0.1

5.1

3.0

0.7

2.7

20.9

3

Cat B

84.9

45.9

0.1

5.8

3.1

0.6

2.5

4

Cat C

87.2

48.3

0.2

2.6

4.8

0.9

5

Cat D

91.4

38.1

0.3

2.3

5.0

0.9

21


0

C3H8

0.8

0.9

48.6 18.0 0.02

0.6

0.3

17.6

45.1 24.1 0.03

0.9

0.2

4.9

23.7

42.1 19.0 0.01

1.3

0.5

5.2

23.4

43.2 17.9 0.01

1.3

0.5


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Page 22 of 29

Table 3. Effect of pH of Solution on Cat B. Reaction Conditions: 40 bar total pressure, 200 ºC, 5 wt% initial solution, 150 mL feed volume, 0.3 g catalyst, 1500 rpm stirring speed, and 4 h reaction time Selectivity, 100%

C-Material balance, 100%

Conversion, 100%

In Water

84.9

45.9

0.1

5.8

0.6

3.1

2.5

0

17.6

45.1 24.1 0.03

0.9

0.2

In 0.1M NaOH

82.2

45.6

0.4

6.9

4.5

9.2

3.3

1

31.9

23.1 19.1

0.5

0.13

Acetone MeOH i-PrOH EtOH

22

n-PrOH


Hydroxyacetone 1,2-PD EG CH4 CO2 C2H6

0

C3H8

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Table 4. Products Hydrogenolysis Experiments on Cat B. Reaction Conditions: 40 bar total pressure, 200 ºC, 5 wt% initial solution, 150 mL feed volume, 0.3 g catalyst, 1500 rpm stirring speed, and 4 h reaction time Selectivity, %

C-Material Conversion, % Acetone balance, %

MeOH

EtOH

i-PrOH n-PrOH Hydroxyacetone 1,2-PD EG CH4 CO2 C2H6 C3H8

EG Feed

81.6

32.7

0.1

42.0

5.5

0

0.1

0

8.1

1,2-PD Feed

84.3

37.0

1.7

4.5

14.9

5.3

3.3

34.4

N/A

0

34.1 0.06 1.5

0.4

MeOH feed

69.8

33.5

0

N/A

0

0

0

0

0

0

99.0 0.15 0.6

0.2

EtOH feed

73.6

30.8

0.1

3.0

N/A

0

0

0

0

0

94.5 0.16 1.7

0.5

n-PrOH feed

53.7

51.6

0

2.2

1.9

0

N/A

0

0

0

53.1 0.17 41.3

1.3

i-PrOH feed

54.9

87.4

85.2

0.3

0.02

N/A

0

0

0

0

9.9

2.9

23


N/A 43.2 0.07 0.9

0.1

1.7

0.2


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

FIGURES

Cat A

Cat B

Cat C

Cat D

Figure 1. SEM images of the four catalysts prepared (before reduction).

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Figure 2. Effect of AlF3 support-content on metal dispersion using hydrogen.

25



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Figure 3. Effect of AlF3 content of the support on glycerol conversion and selectivity of main products. Reaction conditions: 40 bar total pressure, 200 ºC, 5 wt% initial solution, 150 mL feed volume, 0.3 g catalyst, 1500 rpm stirring speed, and 4 h reaction time.

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Figure 4. EG/1,2-PD selectivity ratio for prepared catalysts compared to no-catalyst case.

27



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Figure 5. Hydrogenolysis of individual liquid products. Reaction conditions: 40 bar total pressure, 200 ºC, 5 wt% initial solution, 150 mL feed volume, 0.3 g catalyst, 1500 rpm stirring speed, and 4 h reaction time.

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Biodiesel Factory

Biodiesel

EG + CH4

Crude Glycerol

T = 473 K H2 (4 MPa) 1,2-PD Ru/AlF3-Al2O3


Value-added Chemicals

Page 29 of 29

AlF3-Supported Ruthenium Catalysts for the

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