Reactivity of trihexyl(tetradecyl)phosphonium chloride, a room-temperature phosphonium ionic liquid

Article abstract of DOI:10.1016/j.tetlet.2007.10.131

Trihexyl(tetradecyl)phosphonium chloride 1, a room-temperature ionic liquid, readily undergoes deuterium isotope exchange reaction in deuterated solvents. Under basic conditions, ionic liquid 1 was reactive and 50% deuterium exchanged on all four P-CH₂ methylene groups in 9 h at ambient temperature, 30 min at 50 °C, or 12 min at 65 °C. In addition, ionic liquid 1 reacted with sodium salts of substituted benzoates apparently through the direct S_N2 carboxylate alkylation to form esters 2 and the resulting esters further converted, via Wittig reaction, to finally afford aryl ketones 4.

Full text of DOI:10.1016/j.tetlet.2007.10.131

Available online at www.sciencedirect.com
Tetrahedron Letters 48 (2007) 9085–9089
Reactivity of trihexyl(tetradecyl)phosphonium chloride,
a room-temperature phosphonium ionic liquid
Ming-Chung Tseng, Huang-Chuan Kan and Yen-Ho Chu*
Department of Chemistry and Biochemistry, National Chung Cheng University, 168 University Road,
Min-Hsiung, Chia-Yi, Taiwan, ROC
Received 21 September 2007; revised 24 October 2007; accepted 26 October 2007
Available online 30 October 2007
Abstract—Trihexyl(tetradecyl)phosphonium chloride 1, a room-temperature ionic liquid, readily undergoes deuterium isotope
exchange reaction in deuterated solvents. Under basic conditions, ionic liquid 1 was reactive and 50% deuterium exchanged on
all four P–CH2 methylene groups in 9 h at ambient temperature, 30 min at 50 ꢀC, or 12 min at 65 ꢀC. In addition, ionic liquid 1
reacted with sodium salts of substituted benzoates apparently through the direct SN2 carboxylate alkylation to form esters 2 and
the resulting esters further converted, via Wittig reaction, to finally afford aryl ketones 4.
ꢁ 2007 Elsevier Ltd. All rights reserved.
Ionic liquids are organic salts that are liquid at low tem-
peratures (<100 ꢀC).1 The wide liquid range, superior
thermal and chemical stability, strong solvent power,
and very low vapor pressure have made ionic liquids,
in particular room-temperature ionic liquids, attractive
in many areas of applications such as organic synthesis,
chemical catalysis, separation technology, and novel
electrolytes for solar and fuel cells.1
tions (i.e., the phosphonium cation was not deproto-
nated to produce the corresponding phosphorane).4,5
This result prompted us to further investigate phospho-
nium ionic liquids as we believed that these ionic liquids
would potentially provide the needed chemical stability
as useful media for organic synthesis and relevant bio-
chemical applications.
We envisaged that, besides being reported to be steri-
cally hindered at its central core,4 phosphonium ionic
liquids can be chemically stable for the reason that they
lack the acidic ring protons of the common imidazolium
cations, which limit their general use in synthetic reac-
tions particularly when basic anions are employed.6 Sev-
eral ionic liquids, especially those based on imidazolium
ions such as 1-butyl-3-methylimidazolium ([bmim]),
have been known to be chemically reactive.3f,6,7 Further-
more, these quaternary phosphonium salts were known
to be more stable to high temperatures for longer peri-
ods of time than those nitrogen-based cations.8 To test
its chemical stability, we first investigated this commer-
cially available ionic liquid 1 to see if it resists to solvent
deuterium isotope exchange.5,9
Today the ionic liquid research continues to be domi-
nated by dialkylimidazolium salts with fluorine-contain-
ing anions.1 Studies of quaternary phosphonium
systems, however, are much rare, although these tetra-
alkylphosphonium salts have long been used as phase
transfer catalysts.1,2 In our laboratory, we have been
interested in developing new ionic liquids and have a
program to evaluate ionic liquids as novel and stable
media for chemical and biochemical applications.3
While new and stable bicyclic imidazolium-based ionic
liquids are being developed in our laboratory,3a–c the
commercially available trihexyl(tetradecyl)phospho-
nium chloride 1 as a room-temperature phosphonium-
based ionic liquid was recently reported to be chemically
stable and remain inert with Grignard reagents such as
phenylmagnesium bromide under strongly basic condi-
Using NMR to monitor the reaction, we quickly found,
however, that the ionic liquid 1 was chemically reactive
and readily underwent H–D exchange in basic CD3OD/
D2O (1:1, v/v) solution at ambient temperature (Fig. 1).
Figure 1 shows the time-dependant exchange rate
profile. The solvent exchange rate was measured by
*
Corresponding author. Tel.: +886 5 2428148; fax: +886 5 2721965;
e-mail: cheyhc@ccu.edu.tw
Both authors contributed equally to this work.
0040-4039/$ - see front matter ꢁ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2007.10.131

9086
M.-C. Tseng et al. / Tetrahedron Letters 48 (2007) 9085–9089
100
80
60
40
20
0
100
rt
80
60
40
50 oC
20
0
65 oC
0
50
100
150
200
rt
50 oC
65 oC
0
1000
2000
3000
Time (min)
4000
5000
6000
Figure 1. Solvent deuterium isotope exchanges at P–CH2 of ionic liquid 1 (20 mM) in CD3OD/D2O (1:1, v/v; 0.5 mL) containing 0.1 M KOD at
ambient temperature, 50 ꢀC, and 65 ꢀC, respectively. The progress of deuterium exchange reactions could be readily monitored by 1H NMR. The
inset detailed the progress of exchange reactions of the ionic liquid 1 within the first 200 min. Under the experimental condition, times required at
50% exchange for 1 were approximately 9, 0.5, and 0.2 h at ambient temperature, 50 ꢀC and 65 ꢀC, respectively.
1
observing the changes in the H NMR integrals of all
four P–CH2 protons to that of terminal methyl hydro-
gens (non-exchangeable position) on all alkyl groups.
Results from Figure 1 showed that ionic liquid 1 was
50% deuterium exchanged at P–CH2 protons in approx-
imately 9 h (t1/2) at ambient temperature. For compari-
son, under similar experimental conditions, a bicyclic
imidazolium [b-3C-im][NTf2] ionic liquid recently devel-
oped in our laboratory apparently was much more resis-
tant than ionic liquid 1 to solvent isotope exchange
(t1/2 ꢀ 140 h).3b This result clearly demonstrated that
the commercial ionic liquid 1 possesses acidic and
exchangeable P–CH2 protons10 and is not as chemically
stable as expected.
direct carboxylate alkylation of organobromides with
the presence of Hunig’s base in trihexyl(tetradecyl)phos-
phonium bistriflamide ionic liquid.12 In our hand, after
several initial trials, it was quickly revealed that the
phosphonium cation of ionic liquid 1 was electrophilic
and evidently reacted with substituted benzoate salts
by microwaves at elevated temperature.13 Table 1
showed that, using microwaves (30 W) with temperature
controlled at 180 ꢀC, substituted benzoate salts readily
reacted with ionic liquid 1 to afford aryl ketones 4. All
ketone products (4a–f) were isolated by chromato-
graphy and spectroscopically characterized.13 For all
compounds isolated, satisfactory 1H and 13C NMR,
IR, and MS results were obtained. For example, in IR
spectra, the strong carbonyl absorptions of ketone prod-
ucts 4 obtained by this reaction fall in the region of
1660–1685 cmÀ1. This is consistent with the figures
found generally for aryl ketones.14
Since many organic reactions take place under heated
conditions, we accordingly performed the solvent deute-
rium isotope exchanges of 1 at elevated temperatures (50
and 65 ꢀC) to further explore their suitability for use as
solvents in organic synthesis.9 Results shown in Figure 1
unambiguously demonstrated that, under basic condi-
tions, ionic liquid 1 was highly reactive at elevated tem-
peratures. To be specific, ionic liquid 1 was 50%
deuterium exchanged within 30 min at 50 ꢀC and
12 min at 65 ꢀC, respectively.
On the basis of infrared carbonyl absorption frequencies
and characteristic NMR chemical shifts, we proposed a
mechanism to account for the fact that aryl ketones 4
are reaction products and benzoate esters 2 are the most
probable intermediates. Scheme 1 outlines the proposed
reaction mechanism. As a first reaction intermediate in
the sequence of reactions, the benzoate esters 2 were
formed from the direct SN2 attack of the carboxylate
nucleophile on the electrophilic hexyl or tetradecyl
groups attached to the phosphonium ionic liquid 1. As
soon as esters 2 were produced, each ester then served
as a Wittig substrate and accordingly coupled with
the deprotonated phosphonium 1 (ylide) to carry out
the ‘non-classical’ Wittig reaction to ultimately lead to
the formation of aryl ketone 4.15 Though aldehydes
and ketones are convenient substrates of the Wittig olef-
ination reaction, in the literature phosphonium ylides
Since in our laboratory we have been interested in devel-
oping microwave-accelerated reactions for organic syn-
thesis in ionic liquids3a,d,e and also noted a recent
report that nucleophiles such as sodium benzoate readily
decomposed the [bmim][BF4] ionic liquid under micro-
wave heating at high temperatures (175–225 ꢀC),11 we
decided to conduct experiments to further investigate
the stability of the phosphonium ionic liquid 1 by micro-
waves under heated conditions. Previously, a mild and
high yielding protocol was described and reported for

M.-C. Tseng et al. / Tetrahedron Letters 48 (2007) 9085–9089
9087
Table 1. Reactions of benzoate salts with trihexyl(tetradecyl)phosphonium chloride 1, a room-temperature phosphonium ionic liquid, by microwaves
at 180 ꢀC
O
microwaved at 180 oC
CO2
R1/R2
R1
P
R2
+
R
R
3
1
4
Entry
1
Starting benzoate
R = H
Reaction time (min)
20
Ketone product 4
Isolated yield (%)
R1 = C5H11 (4a)
R2 = C13H27 (4b)
3.8 (14.8a)
3.5
2
3
R = 2-NH2
R = 4-CH3
20
R1 = C5H11 (4c)
R2 = C13H27 (4d)
7.6
2.2
20 + 20
R1 = C5H11 (4e)
R2 = C13H27 (4f)
4.5
2.1
a Yield analyzed and determined by HPLC. Due to product volatility, actual isolated yield was much lower than the analysis yield.
O
O
R1
P
3
R2
+
P
R1
+
O
R2
3
O
R
R
SN2
1
2
Ar
O
O
2
R1
P
3
R2
R1H2C P
1
+
ArCO2
3
Wittig
H
ArCO2H
O
R2
R2
O
O
R2
ArCO2H
H2O
R2
R2
R2
R
R
R
3
4
Scheme 1. Proposed mechanism for aryl ketone (4) formation from the reactions of ionic liquid 1 with sodium benzoates by microwaves with
temperature controlled at 180 ꢀC. Though both hexyl (–CH2R1) and tetradecyl (–CH2R2) groups were accessible to reactions, tetradecyl group was
used here to demonstrate its involvement in the reaction mechanism.
were also known to readily react with reagents with
functional groups such as esters, amides, and anhydrides
to form olefins in a manner analogous to that commonly
observed with aldehydes and ketones.15 In addition,
using benzoate salt as base, complete deprotonation of
1 might not occur. However, as long as the ylide was
in equilibrium with the phosphonium salt, the Wittig
reaction proceeded. In cases of sodium benzoate and
anthranilate (entries 1 and 2 in Table 1), a reaction time
of 20 min was sufficient to produce enough products for
analysis while two consecutive 20 min microwave irradi-
ations for the slow reacting sodium 4-methylbenzoate
(entry 3 in Table 1) were however required. We noted
further that, under the experimental condition, no Wit-
tig adducts (vinyl ethers) 3 were observed or isolated,
and only the hydrolyzed products (aryl ketones) 4 were
obtained (Scheme 1). Under our microwave condition
(30 W, 180 ꢀC), we could not rule out the possibility of
any Hoffmann elimination reaction being taking place
in the presence of benzoate base, simply because of high
volatility of any terminal alkenes if formed. Results in
Table 1 clearly showed that isolated yields of all aryl
hexyl ketones (4a, 4c, and 4e) obtained were higher than
that of aryl tetradecyl ketones (4b, 4d, and 4f). This most
likely was due to the higher molarity of hexyl groups
present in 1.
In summary, we report here for the first time that tetra-
alkylphosphonium cation in ionic liquid 1 is acidic, elec-
trophilic, and can be chemically reactive.16 We have
demonstrated in this study that the commercial ionic
liquid 1 reacted with nucleophiles and, under basic con-
dition, readily underwent deuterium isotope exchange
reaction in deuterated solvents.
Acknowledgments
We thank Ms. Ping-Yu Lin of Academia Sinica (Tai-
wan, ROC) for her excellence in mass analyses. This
work was supported by a multi-year Grant-in-Aid from

9088
M.-C. Tseng et al. / Tetrahedron Letters 48 (2007) 9085–9089
Chem. Soc., Perkin Trans. 1 2000, 505–513; (b) Zhang,
X.-M.; Bordwell, F. G. J. Am. Chem. Soc. 1994, 116, 968–
972.
ANT Technology (Taipei, Taiwan) and in part by the
National Science Council (Taiwan, ROC). We also
thank the reviewers for their constructive comments.
11. Glenn, A. G.; Jones, P. B. Tetrahedron Lett. 2004, 45,
6967–6969.
12. McNulty, J.; Cheekoori, S.; Nair, J. J.; Larichev, V.;
Capretta, A.; Robertson, A. J. Tetrahedron Lett. 2005, 46,
3641–3644.
References and notes
13. General procedure for the reactions of ionic liquid 1 with
substituted benzoate salts by microwaves: To a microwave
reaction vessel containing the ionic liquid 1 (0.8 g) was
added the substituted benzoic acid (150 mg; 1.23 mmol for
benzoic acid, 1.10 mmol for p-toluic acid, 1.09 mmol for
anthranilic acid) and sodium carbonate powder (300 mg,
2.8 mmol). The vessel was placed inside a CEM Discover
single-mode microwave synthesizer equipped with a mag-
netic stirrer where it was exposed to microwaves at 180 ꢀC
(30 W) for 20 min. The progress of the reaction could be
monitored by thin layer chromatography and the exper-
imental condition was, however, not optimized. After
microwaves, the reaction solution was mixed with ethyl
acetate (5 mL), filtered and then concentrated to dryness
in vacuo. The desired products were purified by chroma-
tography (ethyl acetate/hexane = 1:40, v/v) to finally
afford the corresponding aryl ketones (2.1–7.6% yield).
1. For recent reviews, see: (a) Xue, H.; Verma, R.; Shreeve, J.
M. J. Fluorine Chem. 2006, 127, 159–176; (b) Singh, R. P.;
Verma, R. D.; Meshri, D. T.; Shreeve, J. M. Angew.
Chem., Int. Ed. 2006, 45, 3584–3601; (c) MacFarlane, D.
R.; Pringle, J. M.; Johansson, K. M.; Forsyth, S. A.;
Forsyth, M. Chem. Commun. 2006, 1905–1917; (d) Canal,
J. P.; Ramnial, T.; Dickie, D. A.; Clyburne, J. A. C. Chem.
Commun. 2006, 1809–1818; (e) Sheldon, R. A. Green
Chem. 2005, 7, 267–278; (f) Jain, N.; Kumar, A.; Chau-
han, S.; Chauhan, S. M. S. Tetrahedron 2005, 61, 1015–
1060; (g) Chiappe, C.; Pieraccini, D. J. Phys. Org. Chem.
2005, 18, 275–297.
2. Bradaric, C. J.; Downard, A.; Kennedy, C.; Robertson, A.
J.; Zhou, Y. Green Chem. 2003, 5, 143–152.
3. (a) Lin, Y.-L.; Kan, H.-C.; Chu, Y.-H. Tetrahedron 2007,
63, 10949–10957; (b) Kan, H.-C.; Tseng, M.-C.; Chu,
Y.-H. Tetrahedron 2007, 63, 1644–1653; (c) Cheng, J.-Y.;
Chu, Y.-H. Tetrahedron Lett. 2006, 47, 1575–1579; (d)
Tseng, M.-C.; Liang, Y.-M.; Chu, Y.-H. Tetrahedron Lett.
2005, 46, 6131–6136; (e) Yen, Y.-H.; Chu, Y.-H. Tetra-
hedron Lett. 2004, 45, 8137–8140; (f) Hsu, J.-C.; Yen,
Y.-H.; Chu, Y.-H. Tetrahedron Lett. 2004, 45, 4673–
4676.
4. (a) Ramnial, T.; Ino, D. D.; Clyburne, J. A. C. Chem.
Commun. 2005, 325–327; (b) Gorodetsky, B.; Ramnial, T.;
Branda, N. R.; Clyburne, J. A. C. Chem. Commun. 2004,
1972–1973.
1
Satisfactory H and 13C NMR, IR, and MS results were
obtained for all products. Heptanophenone 4a is a
commercially available compound.
Pentadecanophenone 4b: 13 mg (3.5% isolated yield);
white solid; mp 43–44 ꢀC; 1H NMR (CDCl3, 400 MHz)
d 0.86 (t, J = 7.0 Hz, CH3, 3H), 1.24 (br s, 11 · CH2, 22H),
1.71 (qn, J = 7.5 Hz, CH2, 2H), 2.94 (t, J = 7.4 Hz,
CH2C(@O), 2H), 7.43 (t, J = 7.5 Hz, aryl H, 2H), 7.53
(t, J = 7.2 Hz, aryl H, 1H), 7.94 (d, J = 7.3 Hz, aryl H,
2H); 13C NMR (CDCl3, 100 MHz) d 14.1, 22.7, 24.4, 29.3,
29.4, 29.4, 29.5, 29.5, 29.6, 29.6, 29.7, 29.7, 31.9, 38.6,
128.0, 128.5, 132.8, 137.2, 200.6; FTIR (KBr) m 1685 (s)
cmÀ1; EI-HRMS m/z [M+] calcd for C21H34O: 302.2610;
found, 302.2608.
1-(2-Aminophenyl)heptan-1-one 4c: 17 mg (7.6% isolated
yield); colorless oil; 1H NMR (CDCl3, 400 MHz) d 0.85
(t, J = 6.9 Hz, CH3, 3H), 1.23–1.32 (m, 3 · CH2, 6H),
1.68 (qn, J = 7.5 Hz, CH2, 2H), 2.31 (t, J = 7.6 Hz, CH2
C(@O), 2H), 7.05 (t, J = 7.3 Hz, aryl H, 1H), 7.26 (t,
J = 7.8 Hz, aryl H, 2H), 7.50 (d, J = 7.9 Hz, 1H), 7.69 (br
s, NH2, 2H); 13C NMR (CDCl3, 100 MHz) d 14.0, 22.4,
25.6, 28.9, 31.5, 27.7, 119.9, 119.9, 124.1, 128.8, 128.8,
138.1, 171.7; FTIR (KBr) m 1661 (s) cmÀ1; EI-HRMS m/z
[M+] calcd for C13H19NO: 205.1467; found, 205.1471.
1-(2-Aminophenyl)pentadecan-1-one 4d: 7.7 mg (2.2%
isolated yield); white solid; mp 79–80 ꢀC; 1H NMR
(CDCl3, 400 MHz) d 0.86 (t, J = 7.0 Hz, CH3, 3H), 1.24
(br s, 11 · CH2, 22H), 1.70 (qn, J = 7.3 Hz, CH2, 2H),
2.32 (t, J = 7.6 Hz, CH2(C@O), 2H), 7.07 (t, J = 7.3 Hz,
aryl H, 1H), 7.23 (br s, NH2, 2H), 7.29 (t, J = 7.8 Hz, 2H),
7.49 (d, J = 7.8 Hz, 1H); 13C NMR (CDCl3, 100 MHz) d
14.1, 22.7, 25.6, 29.3, 29.3, 29.4, 29.5, 29.6, 29.6, 29.7,
29.7, 29.7, 31.9, 37.9, 119.8, 119.8, 124.1, 129.0, 129.0,
138.0, 171.4; FTIR (KBr) m 1660 (s) cmÀ1; EI-HRMS
m/z [M+] calcd for C21H35NO: 317.2719; found, 317.
2642.
5. This ionic liquid is available from Cytec (CYPHOSꢂ IL
101) and Fluka/Riedel-de Hae¨n. According to Cytec
product description, the ionic liquid typically assays 96
to 97% trihexyl(tetradecyl)phosphonium chloride (1) with
trace contaminants of tetradecene isomers (0.1–0.4%),
hydrochloric acid (0.1–0.5%), and trihexylphosphonium
hydrochloride (0.1–1.2%).
6. For a recent review on the reactivity of ionic liquids, see:
Chowdhury, S.; Mohan, R. S.; Scott, J. L. Tetrahedron
2007, 63, 2363–D2389.
7. Acidity values for C-2 protons (pKa ꢀ 20–30) of a series of
1,3-dialkylimidazolium cations have been measured and
reported: (a) Wang, R.; Yuan, L.; Macartney, D. H.
Chem. Commun. 2006, 2908–2910; (b) Amyes, T. L.;
Diver, S. T.; Richard, J. P.; Rivas, F. M.; Toth, K. J. Am.
Chem. Soc. 2004, 126, 4366–4374; (c) Magill, A. M.;
Cavell, K. J.; Yates, B. F. J. Am. Chem. Soc. 2004, 126,
8717–8724.
8. Del Sesto, R. E.; Corley, C.; Robertson, A.; Wilkes, J. S.
J. Organomet. Chem. 2005, 690, 2536–2543.
9. General procedure for deuterium isotope exchange experi-
ments: The 1H NMR of a mixture of CD3OD/D2O (1:1, v/
v; 0.5 mL) containing 0.02 M ionic liquid 1 (5.2 mg) was
recorded first. To it was then added 0.1 M KOD (3.0 mg).
1
The H NMR spectrum was therefore collected at regular
intervals. The ratio of the integrals of the P–CH2 position
hydrogens to that of the terminal methyl hydrogens (a
non-exchangeable position) on the alkyl group in 1 was
obtained. These values were finally plotted to determine
the rates of the exchange reactions.
1-p-Tolylheptan-1-one 4e: 9.2 mg (4.5% isolated yield);
1
white solid; mp 38–39 ꢀC; H NMR (CDCl3, 400 MHz) d
0.87 (t, J = 7.0 Hz, CH3, 3H), 1.29–1.35 (m, 3 · CH2, 6H),
1.70 (qn, J = 7.4 Hz, CH2, 2H), 2.38 (s, ArCH3, 3H), 2.90
(t, J = 7.3 Hz, CH2C(@O), 2H), 7.23 (d, J = 8.0 Hz, aryl
H, 2H), 7.84 (d, J = 8.0 Hz, aryl H, 2H); 13C NMR
(CDCl3, 100 MHz) d 14.0, 21.6, 22.5,29.1, 31.7, 38.5,
128.2, 129.2, 134.7, 143.5, 200.3; FTIR (KBr) m 1675 (s)
10. The proton removed to form the corresponding ylide in
alkyl(triphenyl)phosphonium salts in dimethyl sulfoxide
has been reported to have a pKa value in the range of 21–
23. For references, see: (a) Russell, M. G.; Warren, S. J.

M.-C. Tseng et al. / Tetrahedron Letters 48 (2007) 9085–9089
9089
cmÀ1; EI-HRMS m/z [M+] calcd for C14H20O: 204.1514;
found, 204.1518.
15. For a review on Wittig reaction of carbonyl compounds
other than aldehydes and ketones, see: Murphy, P. J.;
Brennan, J. Chem. Soc. Rev. 1988, 17, 1–30.
1-p-Tolylpentadecan-1-one 4f: 6.5 mg (2.1% isolated
yield); white solid; mp 45–46 ꢀC; 1H NMR (CDCl3,
400 MHz) d 0.86 (t, J = 7.0 Hz, CH3, 3H), 1.23 (br s,
11 · CH2, 22H), 1.68 (qn, J = 7.4 Hz, CH2, 2H), 2.38 (s,
ArCH3, 3H), 2.90 (t, J = 7.4 Hz, CH2C(@O), 2H), 7.23 (d,
J = 8.1 Hz, Aryl H, 2H), 7.83 (d, J = 8.1 Hz, Aryl H, 2H);
13C NMR (CDCl3, 100 MHz) d 14.1, 22.7, 24.5, 29.3, 29.4,
29.4, 29.5, 29.5, 29.6, 29.7, 29.7, 29.7, 31.9, 38.5, 128.2,
16. Recently, Clyburne and co-workers have reported excel-
lent chemical stability of a Grignard reagent (PhMgBr) in
phosphonium ionic liquids such as trihexyl(tetra-
decyl)phosphonium decanoate and proposed that this
stability was the result of strong Mg–O interactions
between the decanoate anion of the ionic liquid and the
organomagnesium reagent: Ramnial, T.; Taylor, S. A.;
Clyburne, J. A. C.; Walsby, C. J. Chem. Commun. 2007,
2066–2068, This strong complexation of the relatively
large, basic PhMgBr with trihexyl(tetradecyl)phospho-
nium decanoate ionic liquid may likely contribute its
stability in the ionic liquid and consequently no reaction
or decomposition with ionic liquid was observed.
129.2, 134.7, 143.5, 200.3; FTIR (KBr) m 1682 (s) cmÀ1
;
EI-HRMS m/z [M+] calcd for C22H36O: 316.2766; found,
316.2760.
14. Silverstein, R. M.; Bassler, G. C.; Morrill, T. C. Spectro-
metric Identification of Organic Compounds, 4th ed.; Wiley:
New York, 1981, pp 117–123.