Valorisation of plant oil derivatives via metathesis reactions: Study of the cross-metathesis of methyl oleate with cinnamaldehyde

Molecular Catalysis xxx (xxxx) xxx–xxx

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Valorisation of plant oil derivatives via metathesis reactions: Study of the cross-metathesis of methyl oleate with cinnamaldehyde Pablo D. Nieres, Andrés F. Trasarti, Carlos R. Apesteguía

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Catalysis Science and Engineering Research Group (GICIC), INCAPE, UNL-CONICET, Predio CCT Conicet, Paraje El Pozo, (3000) Santa Fe, Argentina

A R T I C LE I N FO

A B S T R A C T

Keywords: Cross-metathesis Oil valorization Methyl oleate Cinnamaldehyde Fine chemistry

The cross-metathesis of methyl oleate (MO) with cinnamaldehyde (CA) to yield 2-undecenal, methyl 11-oxo-9undecenoate, methyl 10-phenyl-9-decenoate and 1-decenylbenzene was investigated using the second-generation Hoveyda-Grubbs Ru complex (HG2). Self-metathesis of methyl oleate was the main undesired secondary reaction. The reaction was carried out at 323 K using reactant molar ratios (RCA/MO) between 1 and 20. The yield (YC-M) and selectivity (SC-M) to cross-metathesis products increased with RCA/MO until reaching both parameters 100% for RCA/MO = 20. The effect of temperature on catalyst activity and selectivity was investigated in the 303–363 K range; YC-M increased significantly with temperature at the expense of the formation of MO selfmetathesis products. No significant HG2 deactivation was observed after performing three consecutive catalytic tests of MO/CA cross-metathesis at 323 K.

1. Introduction The metathesis of oil-derived unsaturated fatty acid methyl esters (FAME) to obtain useful polymers and value-added chemicals is becoming increasingly relevant in oleochemistry [1–3]. Homogeneous catalysts were traditionally used for the metathesis of FAME with ethylene and simple nonfunctionalized olefins to produce less abundant medium-chain fatty acid esters [4–7], although their performance was often limited by their tolerance towards the carboxylic acid or ester groups [8]. More recently, the development of Ru-based complexes remarkably tolerant to the presence of functional groups, moisture and oxygen, such as the second generation complexes from Grubbs et al. [9] and Hoveyda [10], allowed the efficient catalysis of the cross-metathesis of FAME with functionalized olefins. For example, the cross-metathesis of FAME with functionalized olefins such as esters, allylchlorides, and nitriles has been investigated to obtain valuable α,ωbifunctional compounds and polymer precursors from renewable resources [11–15]. The cross-metathesis of FAME with unsaturated aldehydes is also an attractive synthesis route for obtaining valuable chemicals because the formyl group provides direct access to various organic functionalities. The cross-metathesis of α,β-unsaturated aldehydes with nonfunctionalized or simple functionalized olefins has been widely studied using highly active Ru-based olefin metathesis catalysts [16–19]. However, only the paper of Bonin et al. [20] has investigated so far the cross-metathesis of FAME with α,β-unsaturated aldehydes.

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Specifically, Bonin et al. [20] studied the cross-metathesis of methyl oleate with acrolein at 373 K using various Ru catalysts and observed the formation of six products, which revealed the presence of secondary metathesis reactions in the reaction network. Acrolein is a terminal olefin that may deactivate Grubbs’ Ru alkylidenes because of the formation of unstable methylidene intermediates leading to hydride species that suppress the metathesis cycle [21,22]. We decided then to study the cross-metathesis of methyl oleate with α,β-unsaturated aldehydes using as reactant cinnamaldehyde, which is an internal α,βunsaturated aldehyde. Cinnamaldehyde is a natural product that occurs in the bark of cinnamon trees and represents about 60–70% of the essential oil of cinnamon. The products formed from the cross-metathesis of FAME with cinnamaldehyde may be fully obtained then from biorenewable raw materials. In this work, we investigate the cross-metathesis of methyl oleate (MO) with cinnamaldehyde (CA) using the second generation HoveydaGrubbs Ru complex as homogeneous catalyst (Fig. 1). The reaction forms 2-undecenal (2UAL), methyl 11-oxo-9-undecenoate (11UDE), methyl 10-phenyl-9-decenoate (10DE) and 1-decenylbenzene (1DB) as shown in Scheme 1. 2UAL is a fragrance used in cosmetic and perfumery industries [23] and, similarly to other 2-alkenals, presents antibacterial and antifungal activity [24]. Other valuable eleven-carbon aldehydes such as 2-undecanal that is the prototype of the perfumery aldehydes are obtained from 2UAL. 1DB and 11UDE may be used for the synthesis of linear alkylbenzenes that are valuable intermediates to

Corresponding author at: INCAPE, Predio CCT Conicet, Paraje El Pozo, 3000 Santa Fe, Argentina. E-mail address: capesteg@fiq.unl.edu.ar (C.R. Apesteguía). http://www.fiq.unl.edu.ar/gicic/.

https://doi.org/10.1016/j.mcat.2018.06.010 Received 7 May 2018; Received in revised form 31 May 2018; Accepted 6 June 2018

2468-8231/ © 2018 Elsevier B.V. All rights reserved.

Please cite this article as: Nieres, P.D., Molecular Catalysis (2018), https://doi.org/10.1016/j.mcat.2018.06.010

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Fig. 2. Self-metathesis of methyl oleate and cinnamaldehyde. 0 = 0.0145 M, HG2/ [Catalyst: HG2 (1.12 mg), T = 323 K, C0MO = CCA MO = HG2/CA = 1.19 M%, solvent: toluene, 10 ml].

Fig. 1. Second-generation Hoveyda-Grubbs catalyst.

produce biodegradable surfactants [25]. 10DE is a α,ω-bifunctional compound with potential for applications in polymer industry. Secondary reactions in the MO/CA cross-metathesis reaction network are the self-metathesis of MO that produces 9-octadecene (9OCT) and dimethyl 9-octadecen-1,18-dioate (9OD), and the self-metathesis of CA yielding 1,2-diphenylethylene and 2-butenedial. The products of MO self-metathesis, 9OCT and 9OD, may in turn react with CA to form the MO/CA cross-metathesis products (Scheme 1). Here, the MO/CA crossmetathesis was investigated by varying the CA/MO molar ratio (RCA/ MO) between 1 and 20. Results show that the HG2 complex is a very efficient catalyst for the MO/CA cross-metathesis reaction, yielding 100% of cross-metathesis products at 323 K and RCA/MO = 20.

2.2. Catalytic tests The cross-metathesis of MO with CA was carried out in argon using a Schlenk flask at atmospheric pressure in the 303–363 K temperature range. Toluene previously dehydrated with metallic Na and benzophenone under reflux was used as solvent. The reactor was loaded at room temperature under Ar with 10 ml of toluene, n-dodecane (internal standard) and variable amounts of MO and CA. The reaction mixture was stirred and heated to the reaction temperature in a thermostatic bath and then a solution of the HG2 complex in toluene was added to start the reaction. Reaction products were analyzed by ex-situ gas chromatography (GC) in an Agilent 6850GC chromatograph equipped with a flame ionization detector and a HP-1 capillary column (50 m × 0.32 mm ID, 1.05 μm film). The GC response factors of reactants were determined experimentally. Samples (50 μl) from the reaction system were periodically collected in an ice-cooled vial containing methanol to stop the reaction. Product identification was carried out by mass spectrometry using a Thermo Scientific ISQ Single Quadrupole spectrometer coupled with a Thermo Scientific Trace 1300 gas chromatograph equipped with a TR-5MS column (30 m x 0.25 mm ID, 0.25 μm

2. Materials and methods 2.1. Materials Methyl oleate (Aldrich, 99%), cinnamaldehyde (Aldrich, 99%), ndodecane (Aldrich, > 99%), toluene (Sigma-Aldrich, 99.8%), HG2 complex (Aldrich, 97%), benzophenone (Aldrich, 99%), metallic Na (Tetrahedron, 99%), methanol (absolute, Merck), argon (INDURA 5.0).

Scheme 1. Reaction network of the cross-metathesis of methyl oleate with cinnamaldehyde. 2

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Fig. 3. Cross-metathesis of methyl oleate with cinnamaldehyde. 0 = 0.0145M , solvent: toluene]. [Catalyst: HG2 (2.24 mg), T = 323 K, RCA / OM = 1, HG2/MO = 2.38 M%; CMO

3. Results and discussion

Table 1 Equilibrium constants determined at 323 K and RCA/MO = 1. Reaction

Equilibrium constants

MO ⇆ ½ 9OCT + ½ 9OD

K1Eq = 0.53

MO + CA ⇆ ½ 2UAL + ½ 1DB + ½ 11UDE + ½ 10DE

K2Eq = 0.71

9OCT + CA ⇆ 1DB + 2UAL

K3Eq = 1.58

9OD + CA ⇆ 10DE + 11UDE

K 4Eq = 1.13

3.1. Self-metathesis of methyl oleate and cinnamaldehyde The self-metathesis of MO and CA are detrimental secondary reactions for the selective synthesis of MO/CA cross-metathesis products, as shown in Scheme 1. Therefore, we initially carried out catalytic tests at 323 K to assess the activity of HG2 complex for the reactant self-metathesis reactions. We present in Fig. 2 the evolution of MO and CA conversions as a function of time. MO was rapidly converted, and the reaction reached XMO = 50% that is the MO equilibrium conversion at 0 323 K [26,27]. The initial MO conversion rate (rMO , mol/h gHG2) as determined from the slope at t → 0 of the XMO vs t plot in Fig. 2 was 1.14 mol/h gHG2. In contrast, no cinnamaldehyde conversion was observed, even when the reaction test was carried out for 5 h. Other authors have consistently reported that second-generation Grubb’s Ru complexes hardly promote the self-metathesis of α,β-unsaturated aldehydes like 1-phenyl-acrolein [28], and ω-unsaturated aldehydes such as 10-undecenal [18]. In addition, the promotion of self-metathesis of CA by HG2 may suffer from steric constraints because the C]C bond in the CA molecule is conjugated to a phenyl group. Besides, the phenyl group is an electron-withdrawing substituent that may decrease the C]C bond reactivity of CA. In summary, our results show that the selfmetathesis of CA does not take place under the reaction conditions used in this work.

film thickness). Compounds identification was achieved by comparing the mass spectra of the eluting peaks with those of the GC/MS library (NIST 11 database) and by software simulation. Besides the MO/CA cross-metathesis products (2UAL, 11UDE, 10DE and 1DB) it was detected the formation of 9OD and 9OCT from the self-metathesis of MO. Yields were calculated in carbon basis. The yield to MO/CA cross-metathesis products (YC-M, C atoms of cross-metathesis products formed/C ∑α n atoms of MO fed) was determined as YC − M = α ni 0i where ni are the MO MO

moles of product i formed from the cross-metathesis reaction, αi the 0 number of C atoms of MO in the product i molecule, nMO the initial moles of MO, and αMO the number of C atoms in the MO molecule. The yield to MO self-metathesis products was obtained as YS − M =

∑ αj nj 0 αMO nMO

,

where nj are the moles of product j formed from the MO self-metathesis reaction and αj the number of C atoms in the product j molecule. The Y selectivity to cross-metathesis products was obtained as SC − M = XC − M , MO where XMO is the conversion of MO; similarly, the selectivity to the selfYS − M metathesis of MO was calculated as SS − M = X . MO The homo-metathesis of both MO and CA were carried out using the same reaction unit and analytical system than those described above for MO/CA cross-metathesis.

3.2. Cross-metathesis of methyl oleate with cinnamaldehyde 3.2.1. Catalytic tests at 323 K The catalytic performance of HG2 for the cross-metathesis of MO with CA at 323 K and a molar reactant ratio (RCA/MO) of one is shown in Fig. 3. Fig. 3A shows the curves corresponding to reactant conversions (XMO, XCA) and yields to MO/CA cross-metathesis (YC-M) and MO selfmetathesis (YS-M) products, while in Fig. 3B we plotted the product distribution evolution (Y1DB, Y2UAL, Y11UDE, Y10DE, Y9OD, Y9OCT) with

Fig. 4. Cross-metathesis of MO with CA: Addition of CA following the equilibrium of the MO self-metathesis reaction. 0 = 7.25 × 10−3 M, C90OD = C90OCT = 3.625 × 10-3 M, solvent: toluene]. [Catalyst: HG2 (2.24 mg), T = 323 K, HG2/MO = 2.38 M%; CMO 3

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Table 2 Cross-metathesis of methyl oleate with cinnamaldehyde: Catalytic results. Reactanta ratio

Initial CA concentration

Conversionb

Equilibriumc conversion

Yieldb

Selectivityb

Carbonbbalance

R CA/MO

0 CCA (mol/L)

XMO (%)

X CA (%)

XEQ MO (%)

EQ X CA (%)

Y2UAL (%)

Y1DB (%)

Y11UDE (%)

Y10DE (%)

YC − M (%)

YS − M (%)

SC − M (%)

SS − M (%)

% CMOd

2 4 6 8 10 14 18 20

0.0145 0.0290 0.0435 0.0580 0.0725 0.1015 0.1305 0.1450

79 87 91 94 96 97 99 100

50 43 29 26 19 11 9 9

80 87 91 94 96 97 99 100

50 43 29 26 19 11 9 9

13 17 21 22 22 24 26 26

13 17 18 20 21 22 23 23

13 19 20 22 24 25 26 26

13 19 21 22 24 24 24 25

52 72 80 86 91 95 98 100

26 15 10 7 5 2 1 0

67 83 89 92 95 98 99 100

33 17 11 8 5 2 1 0

99 100 99 99 100 99 99 100

0 T = 323 K, CMO = 0.00725 mol/L, WHG2 = 2.24 mg, HG2/MO = 2.38% molar, solvent: toluene (10 mL). a Molar ratio. b At the end of catalytic runs. c Determined from the equilibrium constants of Table 1. d %CMO : Carbon balance for MO conversion.

Table 3 Effect of temperature on catalyst activity and selectivity. Temperature

Conversiona

Yielda

Selectivitya

T (K)

XMO (%)

Y2UAL (%)

Y1DB (%)

Y11UDE (%)

Y10DE (%)

YC − M (%)

YS − M (%)

SC − M (%)

SS − M (%)

303 323 343 363

90 91 92 93

17 21 21 20

18 18 18 20

19 20 22 22

21 21 22 22

75 80 83 84

16 10 8 7

82 89 91 92

18 11 9 8

0 = 0.00725 mol/L, WHG2 = 2.24 mg, HG2/MO = 2.38% molar, solvent: toluene (10 mL). CMO a At the end of catalytic runs.

equilibrium. Here, we determined experimentally the value of equilibrium constant K by adding 1.2 mg of fresh HG2 catalyst at the end of the reaction to confirm that the conversion and yield values in Fig. 3 were not modified by the catalyst addition. Thus, we verified in Fig. 3A Eq that the MO equilibrium conversion ( XMO ) for MO/CA cross-metathesis Eq = 0.80, we deat 323 K and RCA/MO = 1 is 80%. By employing XMO termined the equilibrium constants showed in Table 1 that allowed us Eq to calculate the XMO values for other RCA/MO ratios used in this work. Supporting information on the calculation method employed for determining the reaction equilibrium constants of Table 1 are included in [29]. The curves in Fig. 3A show that when the reaction system reached Eq the equilibrium at XMO = 0.80, the YC-M and YS-M values were 52 and 26%, respectively. To improve the yield to cross-metathesis products, we decided to perform additional catalytic tests by increasing the CA concentration since the reaction equilibrium is shifted to higher MO conversions when RCA/MO is increased. Furthermore, to get insight on the reaction kinetics and mechanism the catalytic tests at increasing RCA/MO ratios were carried out by adding CA following the equilibrium of the MO self-metathesis reaction; i.e the reactor was initially fed only with MO and the self-metathesis reaction proceeded reaching equilibrium; then, CA was added to the reactor and the evolution of the products of the cross-metathesis of CA with MO, 9OCT, and 9OD was followed as a function of time. As illustration, Fig. 4 presents the evolution of XMO, XCA, YC-M and YS-M with the progress of the reaction for RCA/MO ratios of 2, 6 and 10. Clearly, the yield to cross-metathesis products (YC-M) increases at the expense of MO self-metathesis products by increasing RCA/MO. Table 2 presents the values of MO conversions, yields, selectivities, and carbon balances determined at the end of the runs performed using RCA/MO ratios between 2 and 20; in all the cases, C0MO was 0.00725 mol/L. Data in Table 2 show that XMO increased from 79% at RCA/MO = 2 to 100% at RCA/MO = 20; these experimental XMO Eq values were in agreement with the corresponding XMO values determined from the equilibrium constants system of Table 1, thereby

Table 4 Initial conversion rates for the cross-metathesis of MO, 9OD and 9OCT with CA (see Fig. 4). R CA/MO a

2 4 6 8 10 14 18 20

Initial CA concentration (mol/L)

Initial conversión rates (mmol/h gHG2 )

0 CCA

r0MO

0 rCA

0 r9OCT

0 r9OD

0 rC −M

0.0145 0.0290 0.0435 0.0580 0.0725 0.1015 0.1305 0.1450

12.5 17.1 20.6 23.6 25.6 33.1 32.3 33.4

17.6 25.4 29.9 34.4 43.2 47.0 45.1 47.6

4.4 6.3 8.2 10.5 11.5 14.2 14.1 12.3

3.2 4.4 5.1 6.7 7.9 12.5 12.9 12.0

33.3 52.8 59.3 73.9 83.4 100.4 100.5 104.0

Initial formation rate of crossmetathesis products (mmol/h gHG2 )

0 CMO C90OCT C90OD = 3.625 mmol/L, T = 323 K, = 7.25 mmol/L, = WHG2 = 2.24 mg, HG2/MO = 2.38% molar, solvent: toluene (10 mL). a Molar ratio.

the progress of the reaction. MO was initially converted to self-metathesis products 9OD and 9OCT that went through a maximum at about 5 min of reaction because they react with CA to produce 1DB and 2UAL from 9OCT/CA cross-metathesis, and 10DE and 11UDE via 9OD/ CA cross-metathesis, as illustrated in Scheme 1. These results reveal that the conversion rate of MO by self-metathesis is clearly faster than by cross-metathesis with cinnamaldehyde. Fig. 3B shows that the yields to 1DB, 2UAL, 10DE and 11UDE continuously increased with reaction time up to reach equilibrium at the end of the 360-min run. No formation of CA self-metathesis products was detected, thereby confirming the catalytic results presented in Fig. 2. Similarly to other olefin crossmetathesis reactions, the MO/CA cross-metathesis is limited by 4

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Fig. 5. Dependence of cross-metathesis reactions upon CA (A), and MO, 9OCT and 9OD (B). [T = 323 K, catalyst: HG2 (2.24 mg), solvent: toluene].

100% in all the cases, which indicates that HG2 was highly selective for the formation of self- and cross-metathesis products. In summary, data in Table 2 show that the HG2 complex was a very efficient catalyst for the cross-metathesis of MO with CA that yields 100% of the cross-metathesis products at 323 K and RCA/MO = 20.

Fig. 6. Arrhenius plots for determining Ea for cross-metathesis reactions. 0 0 = 7.25 × 10−3 [Catalyst: HG2 (2.24 mg) CCA = 0.0435 M , COM 0 0 = 3.625 × 10-3 M]. C9OCT = C9OD

3.2.2. Effect of temperature MO/CA cross-metathesis catalytic runs were carried at 303 K, 323 K, 343 K and 363 K out to investigate the effect of temperature on catalyst activity and selectivity. In Table 3 we present the values of XMO, yields and selectivities determined at the end of the runs using RCA/MO = 6 and C0MO = 0.00725 mol/L. XMO increased slightly with temperature, from 90% (303 K) to 93% (363 K). In contrast, YC-M was significantly improved at the expense of YS-M, from 75% to 84%, when the temperature was varied from 303 K to 363 K; consistently the selectivity to cross-metathesis products, SC-M increased from 82% to 92% in the same temperature range. In summary, the results in Table 3 show that the yield and selectivity to cross-metathesis products are significantly improved by increasing the temperature.

M,

3.2.3. Kinetic study Reactant conversion rates and product formation rates were determined from the curves obtained following the addition of CA to the reactor once the MO self-metathesis reaction reached equilibrium (see Fig. 4). As depicted in Scheme 1, the reactants are MO, CA, 9OD and 9OCT which form cross-metathesis products via the reaction of CA with 0 MO, 9OD and 9OCT. We determined initial conversion rates rMO , r90OCT , 0 0 r9OD , and rCA , and the initial formation rate of cross-metathesis products (rC0− M ) by polynomial differentiation of the Ci vs t curves at zero time; 0 increased with R CA/MO , from results are shown in Table 4. rMO 12.5 mmol/h gHG2 (R CA/MO = 2) to 33.1 mmol/h gHG2 (R CA/MO = 14); 0 values show that the MO conversion rate by MO/CA crossthese rMO metathesis is about two orders of magnitude lower than by MO self0 metathesis (we determined above that rMO of MO self-metathesis was 1140 mmol/h gHG2 ). Table 4 shows that for all the R CA/MO ratios, the CA conversion rate is like the sum of MO, 9OCT and 9OD consumption rates, which is consistent with the metathesis reaction network presented in Scheme 1. Furthermore, the rC0− M values corresponded ap0 proximately to 2 rCA , in agreement with the reaction mechanism stoichiometries involved in Scheme 1. More fundamental kinetic data were obtained by calculating the reaction orders and apparent activation energies (Ea) for cross-metathesis reactions. The reaction orders were determined at 323 K using the following power-law rate equations that represent the initial conversion rates:

Fig. 7. Consecutive catalytic runs: Yield to cross-metathesis products as a function of time. [T = 323 K, WHG2 = 3.36 mg, RCA/OM = 20, HG2/MO = 3.571 mol%; 0 COM = 7.25 × 10−3 M, solvent: toluene].

indicating that the MO/CA cross-metathesis reaction is not inhibited using high CA concentrations. The yield to cross-metathesis products, YC-M, increased from 52% (RCA/MO =2) to 100% (RCA/MO = 20) at the expense of YS-M; consistently, SC-M increased from 67 to 100% when RCA/MO was varied from 2 to 20. Regarding the product distribution of MO/CA cross-metathesis, Table 2 shows that the relative concentrations of 2UAL, 1DB, 11UDE and 10DE do not change significantly with RCA/ MO. On the other hand, we determined the carbon balance in all the catalytic runs; the last column of Table 2 reveals that %CMO was close to 5

0 0 α1 0 rMO = kMO (CCA ) (CMO ) β1

(1)

0 α2 r90OCT = k 9OCT (CCA ) (C90OCT ) β2

(2)

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0 magnitude lower than by MO self-metathesis. Furthermore, rMO increases with CA and MO concentrations because the reaction is positive order in both reactants. HG2 catalyst did not lose activity by performing three consecutive catalytic tests, thereby exhibiting a high stability for the MO/CA cross-metathesis reaction.

(3)

0 0 0 increased with CCA up to CCA = 0.1015 mol/ Table 4 shows that rMO 0 L (R CA/MO = 14) and remained approximately constant when CCA was increased further, thereby indicating that MO/CA cross-metathesis is 0 zero order with respect to CCA when high R CA/MO ratios are employed. 0 was qualitatively similar to The dependence of r90OCT and r90OD upon CCA 0 . To assess the value of the positive reaction orders that observed for rMO 0 0 , r90OCT and r90OCT , the reaction was studied by varying CCA in CA for rMO 0 0 between 0.00145 and 0.1015 mol/L at CMO = 7.25 mmol/L and C9OCT = C90OD = 3.625 mmol/L. The plots representing ln ri0 as a function of 0 ln CCA are shown in Fig. 5A. Reaction orders α determined from the slopes of logarithmic plots in Fig. 5A were α1 = 0.43, α2 = 0.59 and 0 α3 = 0.56. Similarly, reaction orders β were obtained by varying CMO between 7.25 mmol/L and 21.75 mmol/L, and C90OCT and C90OD in the 0 3.625–10.875 mmol/L range, while keeping CCA constant at 43.50 mmol/L. The reactions orders with respect to MO (β1), 9OCT (β2) and 9OD (β3) obtained from the logarithmic plots of Fig. 5B were 0.44, 0 0.17 and 0.20, respectively. The influence of temperature on rMO , r90OCT and r90OD was investigated between 303 K and 363 K, at 0 CCA = 0.0435 mol/L and RCA/MO = 6. The apparent activation energies (Ea) were determined using an Arrhenius-type function, by plotting ln ri0 0 as a function of 1/T (Fig. 6). The Ea values for rMO , r90OCT and r90OD determined from the slopes of linear plots of Fig. 6 were 8.62 kcal/mol, 11.74 kcal/mol and 11.31 kcal/mol, respectively. The lower Ea value 0 obtained for rMO is consistent with the results presented in Table 4 0 is significantly higher than showing that, at a given R CA/MO ratio, rMO r90OCT and r90OD .

Acknowledgements The authors gratefully acknowledge the Universidad Nacional del Litoral (UNL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), Argentina, for the financial support of this work. References [1] A. Rybak, P.A. Fokou, M.A.R. Meier, Eur. J. Lipid Sci. Technol. 110 (2008) 797–804. [2] S. Mecking, S. Chikkali, Angew. Chem. Int. Ed. 51 (2012) 5802–5808. [3] J.A.M. Lummiss, K.C. Oliveira, A.M.T. Pranckevicius, A.G. Santos, E.N. Dos Santos, D.E. Fogg, J. Am. Chem. Soc. 134 (2012) 18889–18891. [4] R.M. Thomas, B.K. Keitz, T.M. Champagne, R.H. Grubbs, J. Am. Chem. Soc. 133 (2011) 7490–7496. [5] P.D. Nieres, J. Zelin, A.F. Trasarti, C.R. Apesteguía, Catal. Sci. Technol. 6 (2016) 6561–6568. [6] J. Patel, S. Mujcinovic, W. Roy Jackson, A.J. Robinson, A.K. Serelis, C. Such, Green Chem. 8 (2006) 450–454. [7] J. Zelin, P.D. Nieres, A.F. Trasarti, C.R. Apesteguia, Appl. Catal. A: Gen. 502 (2015) 410–417. [8] J.C. Mol, J. Mol. Catal. 90 (1994) 185–199. [9] T.M. Trnka, R.H. Grubbs, Acc. Chem. Res. 34 (2001) 18–29. [10] S.B. Garber, J.S. Kingsbury, B.L. Gray, A.H. Hoveyda, J. Am. Chem. Soc. 122 (2000) 8168–8179. [11] A. Rybak, M.A.R. Meier, Green Chem. 9 (2007) 1356–1361. [12] A. Behr, J.P. Gomes, Z. Bayrak, Eur. J. Lipid Sci. Technol. 113 (2011) 189–196. [13] T. Jacobs, A. Rybak, M.A.R. Meier, Appl. Catal. A 353 (2009) 32–35. [14] R. Malacea, C. Fischmeister, C. Bruneau, J.-L. Dubois, J.-L. Couturier, P.H. Dixneuf, Green Chem. 11 (2009) 152–155. [15] P.D. Nieres, J. Zelin, A.F. Trasarti, C.R. Apesteguia, Eur. J. Lipid Sci. Technol. 118 (2016) 1722–1729. [16] A.K. Chatterjee, J.P. Morgan, M. Scholl, R.H. Grubbs, J. Am. Chem. Soc. 122 (2000) 3783–3784. [17] M. Rivard, S. Blechert, Eur. J. Org. Chem. (2003) 2225–2228. [18] X. Miao, C. Fischmeister, C. Bruneau, P.H. Dixneuf, ChemSusChem. 2 (2009) 542–545. [19] S.M. Rountree, S.F.R. Taylor, Ch. Hardacre, M.C. Lagunas, P.N. Davey, Appl. Catal. A: Gen. 486 (2014) 94–104. [20] H. Bonin, A. Keraani, J.-L. Dubois, M. Brandhorst, C. Fischmeister, C. Bruneau, Eur. J. Lipid Sci. Technol. 117 (2015) 209–216. [21] S.H. Hong, A.G. Wenzel, T.T. Salguero, M.W. Day, R.H. Grubbs, J. Am. Chem. Soc. 129 (2007) 7961–7968. [22] J.C. Conrad, D.E. Fogg, Curr. Org. Chem. 10 (2006) 185–202. [23] http://www.thegoodscentscompany.com/cosdata/perfuming.html. [24] I. Kubo, K. Fujita, A. Kubo, K. Nihei, C.S. Lunde, J. Agric. Food Chem. 51 (2003) 3951–3957. [25] K. Kosswig, “Surfactants” in Ullmann’s Encyclopedia of Industrial Chemistry, WileyVCH, Weinheim, 2013. [26] P.B. Van Dam, M.C. Mittelmeijer, C. Boelhouwer, J. Chem. Soc. Chem. Commun. 22 (1972) 1221–1222. [27] J. Zelin, A.F. Trasarti, C.R. Apesteguía, Catal. Commun. 42 (2013) 84–88. [28] T.L. Choi, C.W. Lee, A.K. Chatterjee, R.H. Grubbs, J. Am. Chem. Soc. 123 (2001) 10417–10418. [29] P.D. Nieres, A.F. Trasarti, C.R. Apesteguia, Data Brief (2018) in press.

3.2.4. Consecutive catalytic tests The stability of HG2 for the MO/CA cross-metathesis was studied at 323 K and RCA/MO = 20 by performing three consecutive catalytic tests without stopping the run. The following procedure was employed: i) the first catalytic cycle was carried out until MO was completely converted and the yield to cross-metathesis products, YC-M, reached 100%; ii) then, we introduced to the reactor the amounts of MO and CA required for obtaining the initial MO and CA concentrations, and performed a second consecutive catalytic cycle until XMO reached again 100%; iii) a third consecutive catalytic cycle was carried out following the same procedure. In Fig. 7 we have plotted the evolution of YC-M as a function of time for the three consecutive catalytic tests. It is observed that the YC-M vs time curves were similar for the three consecutive catalytic runs, thereby showing that the in-situ deactivation of HG2 with the progress of the reaction was not significant. 4. Conclusions The second-generation Hoveyda-Grubbs complex (HG2) efficiently promotes the cross-metathesis of methyl oleate with cinnamaldehyde. Selective formation of cross-metathesis products (2-undecenal, methyl 11-oxo-9-undecenoate, methyl 10-phenyl-9-decenoate and 1-decenylbenzene) increases with both the cinnamaldehyde/methyl oleate ratio and temperature; the reaction yields 100% of cross-metathesis products at 323 K and RCA/MO = 20. Kinetic studies reveal that the MO 0 conversion rate by MO/CA cross-metathesis (rMO ) is about two orders of

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