Comparison of reactivity in the cross metathesis of allyl acetate-derivatives with oleochemical compounds

Article abstract of DOI:10.1007/s11746-015-2614-7

The metathesis of unsaturated oleochemicals is an excellent tool for generating α,ω-difunctional substrates, which are useful intermediates for polymer synthesis. This article describes the cross metathesis of allyl acetate and cis-1,4-diacetoxy-2-butene with methyl 10-undecenoate and methyl oleate, which are oleochemical key substrates. Detailed optimizations led to high conversion rates and yields of the desired products under mild reaction conditions by using a low concentration of commercially available homogeneous ruthenium catalysts.

Full text of DOI:10.1007/s11746-015-2614-7

J Am Oil Chem Soc
DOI 10.1007/s11746-015-2614-7
ORIGINAL PAPER
Comparison of Reactivity in the Cross Metathesis of Allyl
Acetate‑Derivatives with Oleochemical Compounds
Arno Behr · Stephanie Toepell
Received: 24 November 2014 / Revised: 19 January 2015 / Accepted: 3 February 2015
© AOCS 2015
Abstract The metathesis of unsaturated oleochemicals is
an excellent tool for generating α,ω-difunctional substrates,
which are useful intermediates for polymer synthesis. This
article describes the cross metathesis of allyl acetate and
cis-1,4-diacetoxy-2-butene with methyl 10-undecenoate
and methyl oleate, which are oleochemical key substrates.
Detailed optimizations led to high conversion rates and
yields of the desired products under mild reaction condi-
tions by using a low concentration of commercially avail-
able homogeneous ruthenium catalysts.
they even tolerate functional groups such as carboxylic and
ester groups. Therefore, these catalysts can also be used for
applications in oleochemistry [1].
The fatty acid methyl esters examined in this paper are
among the most important agents in oleochemical metath-
esis: Methyl 10-undecenoate 1 (Fig. 1) is a terminal C11-
ester, which can easily be generated by the pyrolysis of
castor oil [2]. Methyl oleate 6 (Fig. 2)—an ester with a C18-
chain length and a cis-9-double bond—can for instance be
obtained from high oleic sunflower oil via transesterifica-
tion with methanol. In recent years, some cross metathesis
(CM) reactions with oleochemical substrates have already
been studied which resulted in bifunctional products with a
number of potentially interesting uses [3–16].
Keywords Oleochemistry · Metathesis · Homogeneous
catalysis · Allyl acetate · cis-1,4-Diacetoxy-2-butene ·
Methyl oleate · Methyl 10-undecenoate
This article describes the reaction optimization of oleo-
chemical cross metathesis reactions in detail. First, the cross
metathesis with methyl 10-undecenoate 1 and methyl oleate
6 with allyl acetate 2 will be illustrated. Then the cross
metathesis of these fatty esters with cis-1,4-diacetoxy-2-bu-
tene 5 will be presented. The latter co-substrate constitutes
the symmetrical analogue of allyl acetate 2. Allyl acetate is
the only by-product of the corresponding cross metathesis,
which in turn can build the same range of products. The
reaction products of the investigated oleochemical cross
metathesis are the difunctional C12-compound 3 based on
methyl 10-undecenoate 1 and the C11-compound 7 based
on methyl oleate 6. Products within this range of chain
length are especially convenient materials for the techni-
cal preparation of surfactants [17, 18]. Furthermore, the
coproducts undec-2-enyl acetate 8 and methyl dec-9-enoate
10 are formed which can be used as platform chemicals,
and could be processed further into polyesters, polyethers
or polyamides. Another possible application is the synthesis
of fine chemicals, such as fragrances or lubricants [3, 19].
Dec-1-ene 9 is generated in the ethylene cross metathesis
Introduction
Recently, the industrial relevance of renewable resources as
alternative raw material has increased significantly. Espe-
cially the chemical utilization of natural fats and oils has
great potential, but also represents a challenge in its indus-
trial application [1]. Oleochemical metathesis reactions in
particular are of great importance in oleochemical research
due to their role in obtaining value-added intermediates for
polymer synthesis. Metathesis is an atom-efficient reac-
tion that usually works under very mild reaction conditions
[2]. Over the years, the homogenous ruthenium metath-
esis catalysts have been developed to such an extent that
A. Behr (*) · S. Toepell
Department of Biochemical und Chemical Engineering, Chair
of Technical Chemistry, Technical University Dortmund,
Emil-Figge Str. 66, 44227 Dortmund, Germany
e-mail: behr@bci.tu-dortmund.de
1 3

J Am Oil Chem Soc
Fig. 1 Self metathesis (SM)
and cross metathesis (CM) of
methyl 10-undecenoate 1 with
allyl acetate 2 and cis-1,4-diace-
toxy-2-butene 5
O
O
+
O
O
O
O
O
3
O
O
3
+
+
O
2
[cat.]
[cat.]
O
SM
O
O
CM
CM
cis-/trans-5
+
O
O
O
[cat.]
2
5
O
O
1
[cat.]
SM
O
O
+
O
O
4
O
O
catalyst activities in the cross-metathesis with terminal ole-
fins [21] or as an intermediate in natural substance synthe-
sis [22]. Allyl acetate 2 is a very interesting substrate for
cross metathesis because of its easy commercial availabil-
ity. The traditional procedure of producing allyl acetate is
the reaction of propene with acetic acid and oxygen in the
gas phase [23]. Its production is also possible by using Pd-
catalyzed oxidation reactions [24]. By contrast, cis-1,4-di-
acetoxy-2-butene 5 is a classic subject of metathesis sub-
strate investigations. Several procedures for oleochemical
cross metathesis reactions have already been published [13,
25–27].
+
O
O
7
9
O
O
+
O
8
O
10
CM
O
+
O
[cat.]
2
O
O
6
SM
+
6
[cat.]
Experimental Procedures
O
O
O
The reactions were carried out at least twice to ensure the
accurate reproducibility of the achieved results. They were
first conducted under argon to check whether this was nec-
essary. All reactions can be handled in the air without a loss
of activity.
O
11
+
12
Fig. 2 Self metathesis (SM) and cross metathesis (CM) of methyl
oleate 6 with allyl acetate 2
Materials
High oleic sunflower oil (HOSO, ca. 91.2 % oleic acid) was
obtained from Emery Oleochemicals GmbH; allyl acetate
(99 %), undecenoic acid (99 %) and the solvents were pur-
chased from Acros in analytical quality (>98 %), the cis-
2-butene-1,4-diol (97 %) was purchased from ABCR. The
benzylidene ruthenium catalysts (see Fig. 3) ([Ru]‑1 and
[Ru]‑2]) were obtained from Sigma-Aldrich, the thioether-
catalysts ([Ru]‑12 and [Ru]‑13) were provided by Evonik
Industries, and the remaining indenylidene catalysts ([Ru]‑
3 up to [Ru]‑11) were provided by Umicore AG & Co. KG
and were used as received.
of methyl oleate 6. Dec-1-ene is an important intermediate
for organic synthesis which can be used for a wide range of
applications, for example, for the synthesis of polyolefins,
lubricants and surfactants [20]. By linking oleochemical
raw materials with commercial petrochemicals value-added
products arise. A partial substitution of petrochemicals with
renewable resources may be a prospective step in the direc-
tion of sustainable chemistry.
Until recently, allyl acetate 2 was only rarely used
in cross metathesis, predominantly in investigations of
1 3

J Am Oil Chem Soc
R3
R
Ph
Cl
Cl
Ru
Ru
R2
Cl
NHC-II:
N
NHC-I:
R1
PCy3
N
N
N
N
Mes
Mes
Mes
Mes
NHC-III:
Mes
L-I:
R1 = R3 = PCy3, R2 = Cl
R1 = PCy3, R2 = Cl, R3 = NHC-I
[Ru]-3
[Ru]-4
[Ru]-1
[Ru]-2
R = PCy3
N
N
Mes
R = NHC-I
L-IV:
L-III:
L-II:
iBu
[Ru]-5
R
1 = R2 = L-I, R3 = NHC-I
O
R
P
O
Cl
[Ru]-6
[Ru]-7
[Ru]-8
R1 = R3 = L-II, R2 = Cl
N
Ru
N
L-V:
O2N
Cl
R
R
1 = L-I, R2 = Cl, R3 = NHC-I
1 = PCy3, R2 = Cl, R3 = NHC-II
S
O
PCy3
N
O2N
[Ru]-9
[Ru]-10
[Ru]-11
R1-R2 = L-III, R3 = NHC-I
R1-R2 = L-IV, R3 = NHC-I
R1-R2 = L-V, R3 = NHC-I
[Ru]-12
[Ru]-13
R = NHC-II
R = NHC-III
Fig. 3 Ruthenium catalysts
Analytical Equipment and Methods
appropriate amount of catalyst was added (1.0 mol%, e.g.
[Ru]‑4 = 0.009 g/0.01 mmol). The reaction was heated to
the desired temperature (range 20–90 °C). After a defined
reaction time (range 30 min–24 h), the closed reaction tube
was placed directly into an ice bath to stop the reaction.
Quenching the reaction by addition of ethyl vinyl ether led
to the same results, so this procedure was not necessary
for the examined reaction. After cooling, the GC samples
were weighed (0.1 g reaction solution, 0.4 g isopropanol
and 0.5 g n-pentadecane as internal standard) and analyzed
accordingly. The reaction mixture was separated with flash
chromatography on silica gel 60 (40–60 µm, Acros Organ-
ics), with the solvents cyclohexane and ethyl acetate having
a gradient of 100:1 up to 10:1. The products were isolated
and characterized via NMR and MS.
Nuclear magnetic resonance (NMR) spectra were recorded in
CDCl3-d6 on a Bruker AVANCE DRX spectrometer operating
at 400 MHz and 500 MHz at 298 K. Chemical shifts (δ) were
indicated in parts per million relative to TMS as internal stand-
ard (TMS, δ = 0.0 ppm). Gas chromatography (GC) analyses
of the reaction solutions were carried out on a Hewlett-Pack-
ard gas chromatograph Series 6,890 equipped with a HP5 cap-
illary column (coating 5 % diphenyl-95 % dimethoxy-polysi-
loxane, length 30 m, diameter 0.25 mm, thickness 0.25 µm)
and an autosampler. A flame ionization detector (FID) was
used for the detection of the components. The oven tempera-
ture program was as follows: initial temperature 130 °C, hold
for 6 min, increased by 25 °C min−1 up to 320 °C, hold for
4 min. Measurements were performed in split–split mode
(70:1) with nitrogen as a carrier gas. The qualitative assign-
ment of the chromatographically determined retention times
of the individual components was carried out by comparing
them to the respective pure substances. The quantitative deter-
minations were made by the method of an internal standard.
The mass spectra were recorded by GC–MS. The mass
spectrometer was a Hewlett-Packard 5,973 with electron
energy of 70 eV and a scan range (m/z) of 50–700. The
oven temperature program, the split–split mode and the
specification of the carrier gas were identical to those in the
GC-FID mode.
Cross Metathesis with cis-1,4-Diacetoxy-2-Butene 5
When using 0.20 g (1.0 mmol) of methyl 10-undecenoate 1
[or 0.30 g (1.0 mmol) methyl oleate 6], 0.87 g (5.0 mmol)
cis-1,4-diacetoxy-2-butene 5, 9.63 g toluene (10.53 g) and
an appropriate amount of catalyst was added (1.0 mol%,
e.g.[Ru]‑4 = 0.009 g/0.01 mmol). The reaction, the sample
preparation and the product isolation occurred analogous to
the cross metathesis described above.
Characterization of the Substrates
Cross Metathesis with Allyl Acetate 2
Methyl 10-Undecenoate 1
When using 0.20 g (1.0 mmol) of methyl 10-unde-
cenoate 1 [or 0.30 g (1.0 mmol) methyl oleate 6], 0.50 g
(5.0 mmol) allyl acetate 2, 6.34 g toluene (7.20 g) and an
Initially, 184.28 g (1.00 mol) methyl undec-10-enoic
acid, 82 mL (2.00 mol) methanol und 4.52 g (26 mmol)
1 3

J Am Oil Chem Soc
p-toluenesulfonic acid were dissolved in 200 mL dichlo-
romethane and heated under reflux for 48 h. After cool-
ing to room temperature, the organic phase was washed
with 100 mL distilled water, 100 mL of a 5 % solution
of sodium bicarbonate, and with another 100 mL of dis-
tilled water consecutively. The solvent was removed under
reduced pressure after drying with sodium sulfate. Finally,
a fractional distillation (83 °C, 10−3 mbar)was carried out
to isolate 178.87 g of methyl 10-undecenoate 1 (0.90 mol,
90 %) with a purity of about 99 % in the form of a clear,
colorless liquid.
33.8, 51.2 (–O–CH3), 65.0 (–O–CH2), 123.5 (–CH–), 136.3
(–CH–), 170.5 (–C(O)–CH3), 173.9 (–C(O)–O–). MS elec-
tron ionization (EI): m/z (%) 271 (1, M+), 227 (10), 210
(8), 196 (27), 178 (25), 168 (9), 161 (3), 149 (13), 136 (12),
129 (6), 121 (9), 112 (10), 95 (21), 81 (28), 67 (27), 55
(37), 43 (100), 28 (67).
Dimethyl Icos-10-Enedioate 4
1H NMR (500 MHz, CDCl3): δ(ppm) = 1.21 (m, 20H, –
CH2–), 1.58 (dd, 4H, J = 7.1 and 14.2 Hz, –C(O)–CH2–
CH2–), 1.96 (m, 4H, –CH2–CH2–), 2.27 (t, 4H, J = 7.6 Hz,
–C(O)–CH2–), 3.64 (s, 6H, –O–CH3), 5.33 (s, 2H, –CH–).
13C NMR (125 MHz, CDCl3):δ(ppm) = 24.9 (–CH2–),
29.0, 29.1, 29.2, 29.3, 29.5, 32.5, 34.0, 51.4 (–O–CH3),
130.2 (–CH–), 174.2 (–C(O)–). MS electron ionization
(EI): m/z (%) 369 (1, M+), 336 (9), 318 (2), 304 (4), 194
(1), 180 (2), 165 (2), 151 (3), 135 (4), 123 (5), 109 (9), 95
(20), 81 (27), 74 (25), 67 (28), 55 (64), 41 (39), 28 (100).
Methyl Oleate 6
First, 300.00 g (0.34 mol) high oleic sunflower oil was
dried at 10−3 mbar at 120 °C for 1 h. After cooling, 35.97 g
(1.12 mol, 3 eq) methanol and 5.59 g (0.10 mol) 30 %
sodium methoxide solution were added, and the reaction
was stirred at 70 °C for 2 h in an inert atmosphere. The
glycerol phase was separated and another 5.42 g (0.12 mol)
methanol was added. After 1 h at 70 °C, the excess of
methanol was evaporated. After separation of the glycerol
phase, the fatty phase was washed twice with 150 mL dis-
tilled water to remove the catalyst and remaining glycerol.
Finally, 88.49 g of methyl oleate 6 (0.30 mol, 88 %) was
isolated as a colorless oil via fractionized distillation at
160 °C and 10−3 mbar with a purity of about 98.5 %.
Methyl 11-Acetoxy Undec-9-Enoate 7
1H NMR (400 MHz, CDCl3): δ(ppm) = 1.23 (bs, 8H, –
CH2–), 1.53 (dd, 2H, J = 7.0 and 14.2 Hz, –C(O)–CH2–
CH2–), 1.98 (m, 5H, –CH–CH2–, –C(O)–CH3), 2.23 (t,
2H, J = 7.5 Hz,–C(O)–CH2–), 3.59 (s, 3H, –O–CH3),
4.43 (d, 2H, J = 6.5 Hz, –C(O)–O–CH2–), 5.49 (m,
1H, –CH–), 5.70 (m, 1H, –CH–). 13C NMR (100 MHz,
CDCl3):δ(ppm) = 20.8 (–C(O)–CH3), 24.7, 27.3, 28.7,
28.8, 28.9, 29.1, 32.0, 33.8, 51.2 (–O–CH3), 65.1 (–O–
CH2–), 135.1 (–CH–), 136.3, 170.6 (–C(O)–), 174.0
(–C(O)–O–). MS electron ionization (EI): m/z (%) 252 (0,
M+), 230 (1), 208 (4), 196 (16), 182 (12), 164 (24), 154
(6), 147 (4), 135 (17), 129 (9), 117 (55), 107 (18), 91 (36),
87 (22), 81 (95), 74 (36), 67 (100), 55 (68).
cis-1,4-Diacetoxy-2-Butene 5
The entire synthesis was performed in an inert atmos-
phere. First, 79.63 g (0.78 mol) fresh distilled acetic acid
anhydride was added dropwise to a solution of 20.26 g
(0.23 mol) cis-2-butene-1,4-diol in 20 mL abs. dichlo-
romethane at 0 °C. Afterwards, 55.37 g (0.7 mol) pyridine
was added dropwise and the solution was stirred for 30 min
at 0 °C. After being stirred for 18 h at room temperature,
the reaction solution was washed three times with 30 mL
2 M HCl and with 25 mL brine. The organic product phase
was dried with MgSO4. After that, the solvent of the reac-
tion was removed. A 35.10-g amount ofcis-1,4-diacetoxy-
2-butene 5 (0.20 mol, 89 %) were isolated as a colorless
liquid with a purity of about 98.5 %.
Undec-2-Enyl Acetate 8
1H NMR (400 MHz, CDCl3): δ(ppm) = 0.86 (t, 3H,
J = 6.8 Hz, –CH3), 1.27 (m, 12H, –CH2–), 2.04 (m, 5H,
–C(O)–CH3, –CH–CH2–), 4.49 (d, 2H, J = 6.5 Hz, –O–
CH2–), 5.67 (m, 2H,–CH–CH–). 13C NMR (100 MHz,
CDCl3):δ(ppm) = 13.9 (–CH3), 20.9 (–C(O)–CH3), 22.5,
24.8, 28.7, 29.0, 29.1, 29.3, 31.1, 65.2 (–O–CH2), 136.6
(–CH–), 138.9 (–CH–), 170.7 (–C(O)–). MS electron ion-
ization (EI): m/z (%)212 (0, M+), 170 (6), 152 (13), 141
(6), 124 (18), 110 (14), 96 (36), 91 (3), 82 (63), 79 (14), 67
(75), 54 (100).
Methyl 12-Acetoxy Dodec-9-Enoate 3
1H NMR (400 MHz, CDCl3): δ(ppm) = 1.25 (m, 10H, –
CH2–), 1.52 (dd, 2H, J = 6.9 and 14.0 Hz, –C(O)–CH2–
CH2–), 1.99 (m, 5H, –CH–CH2–, –C(O)–CH3), 2.21 (t,
2H, J = 7.5 Hz, –C(O)–CH2–), 3.57 (s, 3H, –O–CH3),
4.47 (dd, 2H, J = 6.6 and 44.5, –C(O)–O–CH2), 5.55 (m,
2H, –CH–). 13C NMR (100 MHz, CDCl3): δ(ppm) = 20.8
(–C(O)–CH3), 24.7, 27.3, 28.6, 28.8, 28.8, 28.9, 29.0, 32.0,
Dec-1-Ene 9
1H NMR (400 MHz, CDCl3): δ(ppm) = 0.91 (t, 3H,
J = 6.8 Hz, –CH3–), 1.39 (m, 12H, –CH2–), 2.07 (dt, 2H,
1 3

J Am Oil Chem Soc
J = 6.9 and 14.3 Hz, –CH–CH2–), 4.98 (dd, 1H, J = 4.0 and
8.0 Hz, –CH2–), 5.00 (dd, 1H, J = 4.0 and 16.0 Hz, –CH2–),
5.83 (tdd, 1H, J = 6.7, 10.1 and 16.7 Hz, –CH2–CH). 13C
NMR (100 MHz, CDCl3): δ(ppm) = 13.8 (–CH3), 22.4, 28.7,
28.9, 29.1, 29.3, 31.7, 33.6, 113.8 (–CH2–CH–), 138.8 (–
CH2–CH–). MS electron ionization (EI): m/z (%)141 (5, M+),
111 (16), 97 (34), 83 (43), 70 (84), 56 (96), 41 (100), 29 (43).
performed and a broad number of homogeneous ruthenium
complexes [Ru]‑1 to [Ru]‑13 was tested (Fig. 3) under the
following standard conditions: A catalyst concentration of
1.0 mol% (based on 1), a reaction temperature of 50 °C, a
reaction time of 5 h and a ratio of substrate 1/co-substrate
2 of 1:5 in the solvent toluene. Due to the bidentate Schiff
base ligands the catalysts [Ru]‑9 to [Ru]‑11 required acti-
vation by the addition of 100 equivalents of phenyltrichlo-
rosilane [28, 29].
Methyl-Dec-9-Enoate 10
The silane-activated catalysts [Ru]‑9‑[Ru]‑11 lead to the
highest yields of the desired product 3 and resulted in con-
version rates (X) and yields (Y) of about 60 %. However,
the use of a catalyst without silane activator has the benefit
not to use the toxic PhSiCl3, meaning the synthesis of the
product is more environmentally friendly. Therefore, fur-
ther investigations were carried out with the non-activated
catalyst [Ru]‑4 which has only a slightly lower activity and
conversions of X (1) = 53 % and yields of Y (3) = 44 %.
Different ratios of the substrate 1 and the co-substrate 2
were investigated: At an excess of 1/5 (of 1/2), the yield of
3 increased to 44 %. The conversion of methyl 10-unde-
cenoate 1 decreased by further increasing the amount of
co-substrate 2. Therefore, a ratio of 1:5 was chosen as the
starting point for all further investigations. Because of the
high difference in substrate boiling points, the excess co-
substrate can easily be distilled off after the reaction.
The ratio of substrate to solvent, i.e. the concentration of
substrate, was varied in order to achieve comparable yields
by using a less amount of solvent. The yields of 3 and 4
were highest at a substrate concentration of 10 wt%. The
conversion rate of 1 and the yield of 3 decreased when the
amount of solvent was reduced which maybe caused by the
increased substrate viscosity.
When increasing the reaction temperature up to 80 °C
product yields rise slightly to 46 % which may be caused
again by substrate viscosity. At a temperature of 90°C
isomerization of the C,C-double bond location of the ole-
ochemical compounds 1 and 3 was observed. Therefore,
higher temperatures than 80 °C are not reasonable. The
effect of reaction time was investigated, to determine how
the increased temperature of 80 °C influences the course of
the reaction. The highest yield [Y (3) = 46 %] was detected
after a reaction time of 2 h. By sampling hourly for up to
24 h, it was observed that increased reaction times had no
further effect on the yields of the desired product 3. Longer
reaction times only increased the percentage of the isomeri-
zation of the substrates. The reaction time of 2 h proved to
be very beneficial because only a 2 % yield of the oleo-
chemical self-metathesis product 4 was observed.
1H NMR (400 MHz, CDCl3): δ(ppm) = 1.26 (m, 8H,
–CH2–), 1.57 (m, 2H, –CH2–CH2–C(O)–), 2.00 (m, 2H,
–CH–CH2–), 2.26 (t, 2H, J = 7.2 Hz, –CH2–C(O)–),3.64
(s, 3H, –CH2–C(O)–), 4.88 (dd, 1H, J = 4.0 and 8.0 Hz, –CH–
CH2–(cis)), 4.95 (dd, 1H, J = 4.0 and 16.0 Hz, –CH–CH2–
(trans)), 5.72 (ddt, 1H, J = 8.0, 12.0 and 16.0 Hz, –CH2–CH–).
13C NMR (100 MHz, CDCl3): δ(ppm) = 24.9, 28.9, 29.0, 29.5,
29.6, 32.5, 34.0, 51.4 (–O–CH3), 116.3 (–CH2–CH–), 130.2
(–CH2–CH–), 174.3 (–C(O)–). MS electron ionization (EI):
m/z (%)186 (0,M+), 152 (19), 141 (3), 135 (19), 123 (16), 110
(42), 96 (27), 93 (4), 87 (52), 84 (32), 81 (14), 74 (100), 69
(43), 65 (2), 59 (31), 55 (71), 51 (2), 41 (63), 29 (20), 26 (2).
Dimethyl-Octadec-9-Enedioate 11
1H NMR (400 MHz, CDCl3): δ(ppm) = 1.27 (m, 16H, –
CH2–), 1.58 (m, 4H, –CH2–CH2–C(O)–), 1.93 (m, 4H,
–CH–CH2–), 2.26 (m, 4H, –CH2–C(O)–), 3.63 (s, 6H, –
CH3), 5.34 (m, 2H, –CH–). 13C NMR (100 MHz, CDCl3):
δ(ppm) = 26.4 (–CH2–CH2–C(O)–), 28.6, 30.9, 35.5, 52.8
(–CH3), 131.3 (–CH–), 175.7 (–C(O)–). MS electron ioni-
zation (EI): m/z (%)340 (1, M+), 308 (7), 290 (3), 276 (16),
265 (1), 207 (1), 165 (7), 151 (11), 133 (12), 121 (13), 109
(18), 95 (38), 81 (59), 74 (44), 67 (58), 55 (100).
Octadec-9-Ene 12
1H NMR (400 MHz, CDCl3): δ(ppm) = 0.86 (m, 6H, –CH3–),
1.28 (bs, 24H, –CH2–), 1.97 (m, 4H, –CH2–CH–), 5.37 (m,
2H, –CH–). 13C NMR (100 MHz, CDCl3): δ(ppm) = 13.8
(–CH3), 22.5, 27.0, 28.4, 29.3, 30.7, 31.0, 33.4, 131.3 (–CH–).
MS electron ionization (EI): m/z (%)252 (17, M+), 224 (19),
182 (1), 168 (2), 154 (3), 139 (6), 125 (22), 111 (50), 97
(90), 83 (100), 69 (86), 55 (87), 41 (78), 29 (36).
Results and Discussion
Cross Metathesis (CM) of Methyl 10-Undecenoate 1
and Allyl Acetate 2
Under the previously mentioned optimized reaction con-
ditions the investigation of the catalyst concentration was
performed within the range of 0.05 mol% to 2.0 mol%
(Table 1). In the entire concentration range only a 2 % yield
In the cross metathesis of methyl 10-undecenoate 1 and
allyl acetate 2 (Fig. 1) a detailed catalyst screening was
1 3

J Am Oil Chem Soc
Table 1 Variation of catalyst concentration in the cross metathesis of
1 and 2
electron density of the ruthenium and thereby accelerates
the catalysis [31, 32].
In further investigations, cis-1,4-diacetoxy-2-butene 5,
the symmetric analogue to allyl acetate 2, was used in the
cross-metathesis with methyl 10-undecenoate 1 with the
aim to increase the product yields.
Conc. (mol%)
X (1) (%)
Y (3) (%)
Y (4) (%)
0.05
0.1
26
30
34
44
49
52
52
53
54
15
19
25
35
42
46
45
43
43
2
2
2
2
2
2
2
2
2
0.25
0.5
Cross Metathesis of Methyl 10-Undecenoate 1
and cis-1,4-Diacetoxy-2-Butene 5
0.75
1.0
1.25
1.5
Also in the cross metathesis of methyl 10-undecenoate 1
with the symmetric co-substrate cis-1,4-diacetoxy-2-butene
5 (Fig. 1) the reaction conditions described above were
chosen as the starting point of the investigations (1.0 mol%
[Ru]‑4, T = 80 °C, t = 2 h, 10 wt% substrates, solvent:
toluene). The benefit of this cross metathesis is that no
self-metathesis of 5 is possible. The only “by-product” is
allyl acetate 2, which, however, yields the same products
as using the symmetric co-substrate 5. When investigating
the ratio of the substrates 1 and 5, the best ratio proved to
be 1:3 with a yield of 3 of 87 %. The oleochemical self-
metathesis to product 4 only occurred in traces.
2.0
Reaction conditions: T = 80 °C, t = 2 h, solvent: toluene, catalyst:
[Ru]‑4, 1/2: 1/5, 10 wt% substrates (1 + 2)
Table 2 Variation of the catalyst concentration in the cross metath-
esis of 1 and 5
Conc. (mol%)
X (1) (%)
Y (3) (%)
Y (4) (%)
0.05
0.1
12
39
78
87
89
91
91
92
0
29
73
84
87
87
89
88
0
0
1
1
1
2
2
2
By varying the catalyst concentration (Table 2) the
concentration of 1.0 mol% was seen as a favorable com-
promise as less of the expensive catalyst was required [X
(1) = 89 %, Y (3) = 87 %].
0.25
0.5
1.0
1.25
1.5
In the cross metathesis of 1 and 5 the investigation of the
reaction time showed a result similar to in the reaction with
allyl acetate 2. However, a great benefit of the cross metath-
esis of 1 with 5 is that the highest yield [Y (3) = 87 %] is
reached within 30 min. Longer reaction times led only to
an increased isomerization of the substrates. Hence, the
reaction of methyl 10-undecenoate with the symmetrical
substrate 5 is four times faster than the cross metathesis
with the unsymmetrical substrate 2.
2.0
Reaction conditions: T = 80 °C, t = 2 h, solvent: toluene, catalyst:
[Ru]‑4, 10 wt% substrates (1 + 5), 1/5 = 1/3
of the by-product 4 was observed. At a catalyst concentra-
tion of 1.0 mol%, a maximum yield of product 3 of 46 %
was achieved, rendering a further increase of the amount of
catalyst unnecessary.
Various classes of solvents were investigated to deter-
mine their influence on the reaction. Using cyclohex-
ane, heptane, dichloromethane and ethyl acetate led to
nearly the same results. When using oxygen containing
solvents, such as 1,4-dioxane or tetrahydrofurane, the
yields of the desired product 3 are halved compared to
toluene.
After the optimization, the excess of 2 could be signifi-
cantly reduced to 1:2.5 (of 1/2), which led to a yield of 3 of
49 %.Under these conditions, the catalyst screening was re-
assessed. Comparable results to catalyst [Ru]‑4 were found
with the catalysts [Ru]‑2, [Ru]‑8, [Ru]‑12 and [Ru]‑13
which all do not require an activating agent. They contain a
phenylindenylidene ligand with a greater functional group
tolerance than its benzylidene counterpart [30]. Further-
more, they all contain an NHC-ligand, which increases the
However, in the reaction of 1 with 5 also a high dilution
of the reaction mixture was necessary in comparison to the
metathesis with allyl acetate 2. A substrate concentration of
10 wt% has to be used. As in the case of allyl acetate 2 only
a negligible yield of 1 % of the oleochemical self-metathe-
sis was observed.
The same trends were observed even when examining
the reaction temperature (Table 3). An increased product
yield of 87 % of 3 was detected at a temperature of 80 °C.
At a reaction temperature of 90 °C, isomerization of the
substrates and products were determined. In the solvent
tests the same results were found as observed in the cross
metathesis with allyl acetate 2. Also the analogue catalysts
proved to be the most active.
It can be concluded that in cross metathesis of methyl
10-undecenoate 1 with both symmetric and unsymmetric
substrates the highest product yields are achieved using the
same catalysts under nearly the same reaction conditions.
1 3

J Am Oil Chem Soc
Table 3 Variation of the reaction temperature in the cross metathesis
of 1 and 5
100
90
80
70
60
50
40
30
20
10
T (°C)
X (1) (%)
Y (3) (%)
Y (4) (%)
X (6) [%]
Y (7) [%]
Y (8) [%]
Y (9) [%]
Y (10) [%]
r.t.
30
40
50
60
70
80
90
100
89
88
87
96
91
86
89
90
90
77
76
75
80
84
85
87
87
85
5
6
6
9
4
1
1
1
1
wt% of substrates (2+6)
Fig. 4 Cross metathesis of methyl oleate 6 with allyl acetate 2; Vari-
ation of the concentration of the substrates (2 and 6) using catalyst
[Ru]‑4. Reaction conditions: T = 80 °C, t = 90 min, solvent: toluene,
2 mol% [Ru]‑4, 6/2 = 1/7
Reaction conditions: t = 30 min, solvent: toluene, catalyst: 1.0 mol%
[Ru]‑4, 10 wt% substrates (1 + 5), 1/5 = 1/3
100
90
Further testing is necessary to determine whether this is
transferable to other cross metathesis reactions. Meier et
al. [27] reported a yield of product 3 of 98 % under nearly
similar conditions (50 °C, 3 h, and 0.5 mol% of Grubbs-
Hoveyda-catalyst) using a very low excess of cis-1,4-diace-
toxy-2-butene 5 of only 1:2. However, this procedure has to
use 3 mol% 1,4-benzoquinone to suppress any isomeriza-
tion. The catalysts described in the present article do not
require any auxiliary.
80
70
60
50
40
30
20
10
X (6) [%]
Y (7) [%]
Y (8) [%]
Y (9) [%]
Y (10) [%]
Further investigations were conducted to determine
whether the cross metathesis of allyl acetate 2 showed
similar effects in optimization studies with methyl oleate 6,
i.e., a substrate with an internal double bond.
wt% of substrates (2+6)
Fig. 5 Cross metathesis of methyl oleate 6 with allyl acetate 2; Vari-
ation of the concentration of the substrates (2 and 6) using catalyst
[Ru]‑10. Reaction conditions: T = 80 °C, t = 90 min, solvent: tolu-
ene, 2 mol% [Ru]‑10, 100 eq PhSiCl3, 6/2 = 1/7
Cross Metathesis of Methyl Oleate 6 and Allyl Acetate 2
In contrast to the cross metathesis of the 1-alkene methyl
10-undecenoate 1, an alkene with internal CC-double bond
as methyl oleate 6 yielded a completely different product
spectrum (Fig. 2). Depending on the catalyst system, very
different product ratios were generated. A high ratio of
substrate 6 to co-substrate 2 of 1:7 resulted in the highest
product yields, so this ratio was used in all further inves-
tigations. Figures 4 and 5 show the variation in substrate
concentration with catalyst [Ru]‑4 and catalyst [Ru]‑10,
whereas the latter required 100 equivalents of PhSiCl3 as
activation agent.
With both catalysts a relatively similar product distri-
bution was achieved up to a concentration of substrates of
30 wt%. Using [Ru]‑4 the yields of the products 7 to 10
were nearly constant in the range investigated. Using [Ru]‑
10 the functionalized substrates 7 and 8 achieved values of
about 70 %, whereas the products 9 and 10 only reached
yields of about 20 %.
product distribution to the inner standing products 7 and
8 could be achieved. When varying the catalyst concentra-
tion it was found that with up to 0.25 mol% of [Ru]‑10 all
products were generated to approximately 30 %. A maxi-
mum yield of products 7 and 8 was detected at a catalyst
concentration of 0.75 mol%. The use of a higher catalyst
concentration hinders the reaction, an effect which was also
observed in oleochemical ethenolysis [33].
By varying the ratio of the substrate 6 to co-substrate 2
maximum values of about 75 % of products 7 and 8 were
observed at ratios from 1:5 to 1:6. Investigating the reac-
tion time showed that the reaction equilibrium is given as
early as after 30 min. After a reaction time of 6 h, again
isomerization of the C,C-double bond location of the sub-
strates was detected.
The distribution of the products can be explained by
secondary reactions: For example, the self-metathesis of 9
yields product 12 and the self-metathesis of 10 yields prod-
uct 11. Both reactions are reversible. The self-metathesis of
Subsequent studies of the cross metathesis were carried
out with [Ru]‑10 to determine whether a more effective
1 3

J Am Oil Chem Soc
2. Mutlu H, Meier MAR (2010) Castor oil as a renewable resource
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3. Rybak A, Meier MAR (2007) Cross-metathesis of fatty acid
derivatives with methyl acrylate: renewable raw materials for the
chemical industry. Green Chem 9:1356–1361
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hol with methyl acrylate: optimization of reaction conditions
and comparison of their environmental impact. Green Chem
10:1099–1104
compound 7 produces 11 and 5 and the self-metathesis of
compound 8 yields 12 and 5. In addition all these substrates
can react in further cross metathesis reactions.
Thus, the reaction network is very complex as allyl
acetate 2 is an unsymmetrical, terminal co-substrate. Fur-
ther kinetic investigations are necessary to acquire a deeper
understanding of the product distributions.
In the cross metathesis of methyl oleate 6 with cis-
1,4-diacetoxy-2-butene 5, a 78 % yield of the desired
difunctional product 7 was achieved using [Ru]‑10 as cata-
lyst in a concentration of 1.5 mol% [13]. Again, the experi-
ments demonstrated that the same catalysts had a very
similar activity with both unsymmetric and symmetric co-
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5. Jacobs T, Rybak A, Meier MAR (2009) Cross-metathesis reac-
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thesis of α,ω-difunctional chemical intermediates from renewable
raw materials. Appl Catal A: Gen 353:32–35
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JL, Dixneuf PH (2009) Renewable materials as precursors of
linear nitrile-acid derivatives via cross-metathesis of fatty esters
and acids with acrylonitrile and fumaronitrile. Green Chem
11:152–155
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route to bifunctional aldehyde derivatives via self- and cross-
metathesis of unsaturated aldehydes. Chem Sus Chem 2:542–545
8. Ho TTT, Jacobs T, Meier MAR (2009) A design-of-experiments
approach for the optimization and understanding of cross-metath-
esis reaction of methyl ricinoleate with methyl acrylate. Chem
Sus Chem 2:749–754
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synthesis of two renewable platform chemicals via olefin metath-
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Conclusions
The cross metathesis reactions of methyl 10-undecenoate
1 and methyl oleate 6 with allyl acetate 2 and cis-1,4-diace-
toxy-2-butene 5 were carried out using relatively low concen-
trations of commercially available homogeneous ruthenium
catalysts. The resulting products are interesting intermediates
for polymer production. In all reactions very mild conditions
were sufficient to achieve high conversions and yields.
In the cross metathesis of methyl 10-undecenoate 1,
higher yields of the bifunctional product 3 were reached
with the symmetric substrate cis-1,4-diacetoxy-2-butene 5.
Furthermore, this reaction was faster and a substrate to co-
substrate ratio of only 1:3 was required. The other condi-
tions are similar to the reaction of methyl 10-undecenoate
with allyl acetate 2.
In the cross metathesis of methyl oleate 6 with allyl
acetate 2 a valuable product distribution was only possible
when the reaction conditions were altered. The reaction of
methyl oleate 6 with both allyl acetate 2 and cis-1,4-diace-
toxy-2-butene 5 requires very similar reaction conditions.
These findings may eliminate the need for detailed opti-
mizations when using symmetrical or unsymmetrical sub-
strates in comparable metathesis reactions.
14. Biermann U, Meier MAR, Butte W, Metzger JO (2011) Cross-
metathesis of unsaturated triglycerides with methyl acrylate: syn-
thesis of a dimeric metathesis product. Eur J Lipid Sci Technol
113:39–45
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methyl 10-undecenoate with diethyl maleate: formation of an
α,ω-diester via a metathesis reaction network. Eur J Lipid Sci
Technol 113:189–196
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the cross-metathesis of methyl oleate and oleylamine with ethyl
acrylate. Monatsheft Chemie 143:669–673
17. Mol JC (1994) Metathesis of unsaturated fatty acid esters and
fatty oils. J Mol Catal 90:185–199
Acknowledgments This work was supported financially by the
German Federal Ministry of Food, Agriculture and Consumer Protec-
tion (represented by the Fachagentur Nachwachsende Rohstoffe) and
the Emery Oleochemicals GmbH. The authors would like to thank
Umicore AG & Co. KG and Evonik Industries for their donations of
ruthenium metathesis catalysts.
18. Svensson M (2010) Surfactants based on natural fatty acids.
In: Kjellin M, Johansson I (eds) Surfactants from renewable
resources. Wiley, New York, pp 3–15
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ω-unsaturated fatty acid derivatives. Macromol Chem Phys
202:1114–1121
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