Catalytic hydroxycarbonylation of isobutylene with carbon monoxide and polyhydric alcohols in the presence of the Pd(acac)2-PPh 3-TsOH system

Article abstract of DOI:10.1134/S0965544107050064

The reaction of isobutylene hydroalcoxycarbonylation with CO and polyhydric alcohols (ethylene glycol, glycerol) in the presence of the catalytic system Pd(aacac)₂-PPh₃-TsOH has been investigated. It was found that carbonylation of isobutylene with CO in the presence of ethylene glycol yields a mixture of mono-and diglycol esters of isovaleric acid, irrespective of the initial reactant ratio. During the hydroalcoxycarbonylation of isobutylene with glycerol, either mono- and di- or mono-, di-, and triglycerides of isovaleric acid are formed depending on the reactant ratio.

Full text of DOI:10.1134/S0965544107050064

ISSN 0965-5441, Petroleum Chemistry, 2007, Vol. 47, No. 5, pp. 345–347. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © H.A. Suerbaev, E.G. Chepajkin, B.Zh. Dzhiembaev, I.O. Appazov, G.M. Abyzbekova, 2007, published in Neftekhimiya, 2007, Vol. 47, No. 5, pp. 376–378.
Catalytic Hydroxycarbonylation of Isobutylene with Carbon
Monoxide and Polyhydric Alcohols in the Presence
of the Pd(acac)2–PPh3–TsOH System
H. A. Suerbaeva, E. G. Chepajkinb, B. Zh. Dzhiembaeva, I. O. Appazova, and G. M. Abyzbekovaa
a Al-Farabi Kazakh National University, ul. al-Farabi 71, Almaty, 050038 Republic of Kazakhstan
b Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, 142432 Russia
e-mail: echep@ism.ac.ru; grig@ism.ac.ru
Received September 27, 2007
Abstract—The reaction of isobutylene hydroalcoxycarbonylation with CO and polyhydric alcohols (ethylene
glycol, glycerol) in the presence of the catalytic system Pd(aacac)2–PPh3–TsOH has been investigated. It was
found that carbonylation of isobutylene with CO in the presence of ethylene glycol yields a mixture of mono-
and diglycol esters of isovaleric acid, irrespective of the initial reactant ratio. During the hydroalcoxycarbony-
lation of isobutylene with glycerol, either mono- and di- or mono-, di-, and triglycerides of isovaleric acid are
formed depending on the reactant ratio.
DOI: 10.1134/S0965544107050064
INTRODUCTION
EXPERIMENTAL
A 0.035-g portion of Pd(acac)2 (1.1 × 10–4 mol),
0.212 g (8.085 × 10–4 mol) of PPh3, 0.263 g (1.386 ×
10−3 mol) of TsOH, and 3.94 g (6.35 × 10–2 mol) of eth-
ylene glycol or 5.858 g (6.35 × 10–2 mol) of glycerol
were loaded into a 150-ml steel autoclave. The auto-
clave was hermetically closed, purged twice with CO
for the removal of air from the system, and then filled
with carbon monoxide up to a pressure of 1.0–1.1 MPa.
Then, a calculated quantity of isobutylene (one- or two-
fold quantity relative to ethylene glycol; one-, two-, or
threefold quantity relative to glycerol) was introduced
into the autoclave, and the carbon monoxide pressure
was increased to 2.0 MPa. Stirring and heating were
switched on. The reaction mixture was stirred within
4 h at a temperature of 100°C and a pressure of
2.0 MPa. Then the autoclave was allowed to cool down
to a room temperature and left for a night. The next day,
after the pressure was released to atmospheric, the reac-
tion mixture was fractionated in vacuo (1 mmHg). The
desired products were separated from the obtained mix-
ture of products with unreacted polyols by means of
column adsorption chromatography on silica gel
(0.005−0.04 mm). Chloroform and a chloroform : metha-
nol blend (9 : 1 by volume) were used as eluents. The
identity of the obtained products was determined by
means of thin-layer chromatography, elemental analy-
sis, and IR-spectroscopy.
Isobutylene as an accessible and inexpensive feed-
stock is of interest for synthesis of many practically
useful compounds. Isobutylene carbonylation with car-
bon monoxide and alcohols under the conditions of
homogeneous catalysis by transition metal complexes
is an effective process for the manufacture of isovaleric
acid esters, which exhibit biological activity and are
used as ingredients of pharmaceuticals (validol, valo-
cordin, etc.) [1].
It should be noted that, in all available works on the
synthesis of carboxylic acids esters via the olefin
hydroxycarbonylation reaction, short-chain monohy-
dric aliphatic alcohols are mainly used as alcoholic
reagents [2]. There is one communication on the syn-
thesis of phenylcarboxylates via hydrophenoxycarbon-
ylation [3]. Adaptation of this method to polyhydric
alcohols with the purpose of production of carboxylic
acid polyol esters is certainly of considerable practical
interest. For example, the esters have found wide appli-
cation as plasticizers, components of pharmaceuticals
and cosmetics, wetting and emulsifying agents, etc. [4].
There is also a brief record of the use of palladium com-
plexes [5] and several patents of the Japanese group [6–
8] in which two-component catalytic systems based on
cobalt, nickel, or rhodium chlorides; carboxylates; and
carbonates and pyridine are claimed.
The purpose of the present work was investigation
of the isobutylene hydroxycarbonylation reaction with
carbon monoxide and polyhydric alcohols (ethylene
glycol, glycerol) in the presence of the catalytic system
Pd(Acac)2–PPh3–TsOH.
The purity of the products was determined by thin-
layer chromatography on Silufol (Czech Republic) in a
chloroform : methanol (9 : 1 by volume) system of sol-
vents or in chloroform. IR spectra were obtained for
345

346
SUERBAEV et al.
liquid compounds on a Nicolet 5700 spectrophotome-
ter.
Isovaleric acid monoglycol ester. Rf = 0.22 (Silu-
fol; CH3Cl). Found, %: C 57.60; H 9.78. Calculated for
ë7ç14é3, %: C 57.5; H 9.7.
Isovaleric acid triglyceride. Rf = l.13 (CHCl3:
CH3OH = 9 : 1). Found, %: C 63.00; H 9.44. Calculated
for C18H32O6, %: C 62.77; H 9.36.
Isovaleric acid diglycol ester. Rf 0.52 (Silufol;
CH3Cl). Found, %: C 61.76; H 9.4. Calculated for
ë12ç22é4, %: C 62.6; H 9.6.
Isovaleric acid a-monoglyceride. Rf = Œ.39
(CHCl3 : CH3OH = 9 : 1). Found, %: C 53.60, H 9.16.
Calculated for C8H16O4, %: C 54.53; H 9.15.
Isovaleric acid a,a'-diglyceride. Rf = 0.68
(CHCl3 : CH3OH = 9 : 1). Found, %: C 59.99; H 9.29.
Calculated for C13H24O5, %: C 59.98; H 9.29.
RESULTS AND DISCUSSION
It was found that carbonylation of isobutylene by
carbon monoxide in the presence of ethylene glycol and
the catalytic system Pd(Acac)2–PPh3–TsOH does not
depend on the ratio of the reactants (isobutylene, ethyl-
ene glycol) and yields a mixture of mono- and diglycol
esters of isovaleric acid.
(CH3)2C=CH2 + CO + HOCH2CH2OHCatalyst(CH3)2CHCH2C(O)OCH2CH2OH
+ (CH3)2CHCH2C(O)OCH2CH2O(O)CCH2CH(CH3)2
Catalyst = Pd(Acac)2–PPh3–TsOH
At an [isobutylene] : [ethylene glycol] ratio of 1 : 1, ester) and 1739.1 cm–1 (diglycol ester), as well as the
mono- and disubstituted esters of ethylene glycol are
formed with yields of 35.8 and 12.9%, respectively. At
[isobutylene] : [ethylene glycol] = 2 : 1, the yield of
monoglycol ester is 9.9% and that of diglycol ester of
isovaleric acid amounts to 24.1%.
“ester band” (vibrations of the ester C–O–C group) at
1193.8 cm–1 (monoglycol ester) and 1189.7 cm–1 (di-
glycol ester). For monoglycol ester of isovaleric acid,
there is an absorption band at 1098 cm–1 characteristic
of a primary hydroxyl group of alcohols, as well as a
broad absorption band of associated hydroxyl group at
The IR spectra of the synthesized isovaleric acid
glycol esters display typical absorption bands of esters:
the intense carbonyl band at 1736.5 cm–1 (monoglycol 3300–3500 cm–1.
CH –OC(O)CH CH(CH )2 CH –OC(O)CH CH(CH )2
CH2–OH
CH–OH + CO + (CH3)2C=CH2CatalysCt H–OH
CH2–OH CH2–OC(O)CH2CH(CH3)2
CH2–OH
2
2
3
2
2
3
CH–OH
CH–OC(O)CH CH(CH )
.
2 3 2
+
+
CH –OC(O)CH CH(CH3)2 CH –OC(O)CH CH(CH3)2
2
2
2
2
Carbonylation of isobutylene with carbon monoxide
Note that, in contrast to the known processes for the
manufacture of glycerides of fatty acids by the direct
esterification of the acids with glycerol and by transes-
terification of methyl (or ethyl) esters of fatty acids with
glycerol when a mixture of α- and β-isomers of
monoglycerides is formed [9, 10], the formation of the
[alpha]-isomer alone is observed during the hydroxy-
carbonylation of isobutylene with carbon monoxide
and glycerol.
in the presence of glycerol and the catalyst system
Pd(Acac)2–PPh3–TsOH proceeds in several steps.
According to available data, the secondary hydroxyl
group of glycerol reacts more slowly than a primary
one. At ratios of [isobutylene] : [glycerol] = 1 : 1 and
2 : 1, mono- and diglycerides are formed, and mono-,
di-and triglycerides are formed when the ratio is 1 : 3.
The maximum total yield of glycerides (23.3 %) was
obtained at a ratio of [isobutylene] : [glycerol] = 2 : 1;
the yields of monoglyceride and diglyceride make up
19.1 and 4.2%, respectively, in this case. The yields of
mono-and diglycerides at [isobutylene] : [glycerol] =
1 : 1 are 9.3 and 1.1%, respectively. At a ratio of [isobu-
tylene] : [glycerol] = 3 : 1, mono-, di-, and triglycerides
were obtained with yields of 14.7, 3.0, and 0.4%,
respectively.
The IR spectra of isovaleric acid glycerides are char-
acterized by typical absorption bands of esters: the car-
bonyl band at 1735–1740 cm–1 and the “ester band”
(stretching vibrations of the ester C–O–C group) at
1188–1191 cm–1. For monoglyceride and diglyceride,
there are absorption bands at 1051 and 1121 cm–1,
which are characteristic of primary and secondary alco-
holic hydroxyls, and a broad absorption band of associ-
ated hydroxyl groups in the range of 3403–3466 cm–1.
PETROLEUM CHEMISTRY Vol. 47 No. 5 2007

CATALYTIC HYDROXYCARBONYLATION OF ISOBUTYLENE
347
4. A. F. Artamonov, Doctoral Dissertation in Chemistry
(Kazakh National Univ. Almaty, 2005).
Thus, the feasibility of the synthesis of isovaleric
acid esters with aliphatic polyols by means of alkoxy-
carbonylation of isobutylene in the presence of the cat-
alytic system Pd(Acac)2–PPh3–TsOH was established.
The reaction proceeds regioselectively at the terminal
atom of isobutylene. Isovaleric acid monoglyceride is
formed only in the form of the α-isomer.
5. E. G. Chepaikin, A. P. Bezruchenko, A. Ben’ei, and F. Io,
Izv. Akad. Nauk SSSR, Ser. Khim., No. 3, 743 (1989).
6. H. Isa, T. Inagaki, Y. Kiyonaga, and M. Nagayama, BD
Patent 2 404 955 (1974); Chem. Abstr. 83 27605 (1975).
7. H. Isa, T. Inamoto, Y. Kiyonaga, and M. Nagayama, JP
Appl. 74 108 013 (1974); Chem. Abstr. 82 155386
(1975).
REFERENCES
8. H. Isa, T. Inagaki, Y. Shimizu, and M. Nagayama, JP
1. M. D. Mashkovskii, Medicines 10th Ed. (Meditsina,
Appl. 7 562 925 (1975); Chem. Abstr. 83 96 454 (1975).
Moscow, 1987) [in Russian].
9. N. A. Artamonova, M. I. Goryaev, Yu. A. Morozova, and
O. I. Efremova, Izv. Akad. Nauk Kaz. SSR, Ser. Khim.,
No. 2, 35 (1979).
2. E. G. Chepaikin, A. P. Bezruchenko, Kh. A. Suerbaev,
and K. M. Shalmagambetov, Neftekhimiya 46, 134
(2006) [Pet. Chem. 46, 117 (2006)].
3. V. A. Aver’yanov, N. M. Nosova, and S. A. Batashev, 10. N. A. Artamonova, A. F. Artamonov, L. P. Petelina, et al.,
Neftekhimiya 46, 116 (2006) [Pet. Chem. 46, 99
(2006)].
Vestn. Karakalpak. Filiala Akad. Nauk Uz. SSR, No. 3,
13 (1988).
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