New synthesis of Dialkyl carbonates from alkylene carbonates and titanium alkoxides

Full text of DOI:10.1134/S1070428013070208

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 7, pp. 1078–1079. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © V.A. Kuznetsov, A.V. Pestov, M.G. Pervova, Yu.G. Yatluk, 2013, published in Zhurnal Organicheskoi Khimii, 2013, Vol. 49, No. 7,
pp. 1092–1093.
SHORT
COMMUNICATIONS
New Synthesis of Dialkyl Carbonates from Alkylene Carbonates
and Titanium Alkoxides
V. A. Kuznetsov, A. V. Pestov, M. G. Pervova, and Yu. G. Yatluk†
Postovskii Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences,
ul. S. Kovalevskoi/Akademicheskaya 22/20, Yekaterinburg, 620990 Russia
e-mail: kuznetsov@ios.uran.ru
Received December 5, 2012
DOI: 10.1134/S1070428013070208
Dialkyl carbonates are used in industry as organic
solvents, fuel additives, lubricants in refrigerating
units, and heat carriers. A conventional procedure for
the preparation of dialkyl carbonates is based on the
reaction of alcohols with phosgene which is very toxic.
Phosgene-free syntheses of organic carbonates are ex-
tensively developed; they include oxidative carbonyla-
tion of alcohols [1, 2], reactions of alcohols with urea
[3, 4], reactions of oxiranes with carbon dioxide [5, 6],
and reactions of inorganic carbonates with alkyl
halides [5] or alcohols [7, 8]. Also, mutual transforma-
tions of alkyl carbonates are possible.
We now propose a new phosgene-free synthesis of
dialkyl carbonates via reaction of alkylene carbonates
with titanium alkoxides. An advantage of the proposed
procedure is that it ensures simultaneous preparation of
two important products, dialkyl carbonate and alkyl
titanate derivative [dialkyl alkanediyl titanate or bis-
(alkanediyl) titanate]. The latter can be used as curing
agent for epoxy resins or as precursor for the synthesis
of nanosized titanium dioxide. The titanium-containing
residue can be decomposed by treatment with dilute
sulfuric acid to regenerate the diol.
A mixture of 45.62 g (0.2 mol) of tetraethyl titanate
and 40.8 g (0.4 mol) of propylene carbonate was
slowly heated and distilled through a column, and
a fraction boiling in the range from 120 to 130°C was
collected. Yield of diethyl carbonate 40.59 g (86%),
nD = 1.384 (published data [9]: nD = 1.384). Found, %:
C 50.84; H 8.45. Calculated, %: C 50.85; H 8.47.
The undistillable residue was partly hydrolyzed bis-
(propane-1,2-diyl) titanate. Yield 38.97 g (99%).
Found, %: C 36.69; N 6.11; Ti 24.56. Calculated, %:
C 36.76; N 6.17; Ti 24.42.
The reaction with equimolar amounts of the reac-
tants was carried out in a similar way using 45.62 g
Synthesis of dialkyl carbonates by transesterification of
tetraalkyl titanates with alkylene carbonates
Alkylene carbonate
Propylene carbonate
R in Ti(OR)4 na
Yield, %
1
2
1
2
1
2
1
2
1
2
1
2
77
86
86
87
25
02
92
96
48
57
88
95
R = Et
R = Pr
R = i-Pr
R = Bu
The reactions were carried out with a number of
alkyl titanates and alkylene carbonates.
O
O
Ti(OR)4
+
n
R'
O
( )x
Ethylene carbonate
O
O
R'
Ti(OR)4–2n
+
n
Trimethylene carbonate
R
R
( )x
O n
n = 1, 2; x = 1, 2; R = Et, Pr, i-Pr, Bu; R′ = H, Me.
Deceased.
a
n is the number of moles of alkylene carbonate per mole of tetra-
†
alkyl titanate.
1078

NEW SYNTHESIS OF DIALKYL CARBONATES FROM ALKYLENE CARBONATES
1079
(0.2 mol) of tetraethyl titanate and 20.4 g (0.2 mol) of
propylene carbonate. Yield of diethyl carbonate
18.17 g (77%), nD = 1.384 (1.384 [9]). Found, %:
C 50.85; H 8.46. Calculated, %: C 50.85; H 8.47. The
undistillable residue was partly hydrolyzed diethyl
propan-1,2-diyl titanate. Yield 41.09 g (97%). Found,
%: C 38.68; H 7.52; Ti 23.30. Calculated, %: C 39.65;
H 7.60; Ti 22.57.
an IRF-22 refractometer. The elemental compositions
were determined using a Perkin Elmer automatic
analyzer.
This study was performed under financial support
by the Ural Branch of the Russian Academy of
Sciences (project no. 11-3-IP-286).
REFERENCES
The reactions with tetrapropyl, tetraisopropyl, and
tetrabutyl titanates, as well as with ethylene and
trimethylene carbonates, were carried out in a similar
way. The results are collected in table. Following
an analogous procedure, diethyl carbonate can be ob-
tained from tetraethyl titanate and dibutyl carbonate.
This is a rare example of the transformation of a higher
ester into lower. Any alkyl carbonate may be converted
in turn into alkylene carbonate. For this purpose,
a catalytic amount of titanium alkoxide is sufficient,
though the best catalysts are sodium alkoxides. Such
transformation sequence ensures preparation of tri-
methylene carbonate from diethyl or dimethyl
carbonate.
1. Kondo, K., Sonoda, N., and Tsutsumi, S., Tetrahedron
Lett., 1971, vol. 12, p. 4885.
2. Rivetti, F. and Romano, U., EP Patent Appl. no. 0534545,
1991; Chem. Abstr., 1993, vol. 119, no. 138752.
3. Wang, H., Lu, B., Wang, X., Zhang, J., and Cai, Q., Fuel
Proc. Technol., 2009, vol. 90, p. 1198.
4. Jong, R.D. and Abrakham, D., Russian Patent
no. 2367648, 2004; Ref. Zh., Khim., 2010, no. 19N48P.
5. Shaikh, A.-A.G. and Sivaram, S., Chem. Rev., 1996,
vol. 96, p. 951.
6. Shim, H.-L., Udayakumar, S., Yu, J.-I., Kim, I., and
Park, D.-W., Catal. Today, 2009, vol. 148, p. 350.
7. Chu, F., Dueno, E.E., and Jung, K.W., Tetrahedron, 1999,
vol. 40, p. 1847.
The products were identified by GLC, as well as by
refractometry and elemental analysis. The GC/MS
identification was performed using an Agilent GC
7890A MSD 5975C inert XL EI/CI instrument
(quadrupole mass-selective detector; electron impact,
70 eV). The refractive indices were measured using
8. Salvatore, R.N., Chu, F., Nagle, A.S., Kapxhiu, E.A.,
Cross, R.M., and Jung, K.W., Tetrahedron, 2002, vol. 58,
p. 3329.
9. Spravochnik khimika (Chemist’s Handbook), Nikol’-
skii, B.P., Ed., Moscow: Khimiya, 1967, 2nd ed., vol. 4,
p. 822.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 7 2013