Journal of Catalysis 194, 188–197 (2000)
doi:10.1006/jcat.2000.2945, available online at http://www.idealibrary.com on
A Novel Production of � -Butyrolactone Catalyzed
by Ruthenium Complexes
Yoshinori Hara,�,1
�
�
�
Haruhiko Kusaka, Hiroko Inagaki, Kazunari Takahashi,† and Keisuke Wada
�
Yokohama Research Center, Mitsubishi Chemical Corporation, 1000, Kamoshida-cho, Aobaku, Yokohama 227-8502, Japan; and †Development
and Engineering Research Center, Mizushima Plant, Mitsubishi Chemical Corporation, 10, Ushiodouri-3chou-me, Kurashiki 712-8504, Japan
Received November 2, 1999; revised May 22, 2000; accepted June 2, 2000
acetylene and formaldehyde. GBL can also be produced
�
-Butyrolactone (hereafter abbreviated GBL) is produced by the based on the hydrogenation of MAH, which is the way it is
two-stage hydrogenation of maleic anhydride (MAH) in the liquid manufactured in Japan. Butane-based MAH is now avail-
phase: the hydrogenation of MAH to succinic anhydride (SAH) in
the first stage and the subsequent hydrogenation of SAH to GBL in
the second stage. The latter hydrogenation has been studied using
a homogenous catalyst. A novel ruthenium catalyst system consist-
ing of Ru(acac)3, P(octyl)3, and p-toluenesulfonic acid ( p-TsOH)
not require the use of hazardous materials (such as in the
was developed for hydrogenating the SAH, which exhibited excel-
lent catalytic performance, exceeding 95% selectivity for GBL and
higher activity than that reported in the literature. It was found that
p-TsOH plays an important role not only in enhancing the reaction
able in sufficient amounts at reasonable prices because of
the construction of a large-scale fluid-bed MAH plant; the
hydrogenation of MAH is the direct method of production
of GBL, which is believed to proceed via SAH and does
Reppe process).
Various reasearch projects have carried out extensive
studies of the hydrogenation of MAH over different no-
rate, but also in improving selectivity. p-TsOH induces a structual bel metals and Cu catalysts both in the gas phase and in the
change in the Ru complexes, leading to the cationic change which liquid phase. For example, Castiglioni et al. (2) showed that
shows higher catalyst activity. It also prevents the undesired side GBL can be obtained by the vapor phase hydrogenation
reaction catalyzed by free P(octyl)3 thus resulting in high selectivity
for GBL. A process to produce GBL was investigated. Some novel
features of this process include the external preparation method of
the Ru complex, the coupling reaction, and the separation to remove
H2O, a product of hydrogenation of SAH, to increase the reaction
However, generally, heterogenous catalysts do not al-
rate. A catalyst recovery system was also developed to recover over
of MAH if copper catalysts with promoted Zinc oxide are
used. Also, some patents disclose the liquid phase hydro-
genation of MAH in the presence of a supported Pd–Re
catalyst (3) and Ni–Co oxide catalyst (4).
ways exhibit satisfactory selectivity for GBL due to the
9
0% of the catalyst.
�c 2000 Academic Press
formation of many different and less valuable by-products
like n-butanol and butyric acid caused by hydrogenol-
ysis and the overhydrogenation reaction. On the other
hand, Lyons (5) first pointed out in 1975 that Ru com-
plexes, such as RuCl2(PPh3)3, could catalyze the hydro-
genation of SAH to give GBL under mild conditions.
Later, various types of Ru catalysts have been proposed.
Yoshikawa et al. (6) reported that the unsymmeterically
substituted succinic anhydride catalyzed by Ru2Cl4(dppb)2
Key Words: hydrogenation; succinic anhydride; � -butyrolactone
production; homogeneous ruthenium catalyst.
INTRODUCTION
The demand for GBL is steadily growing because of its
major use as an important intermediate and its direct use as
a dielectric material or a solvent. According to Morgan (1),
more than 70,000 tons of GBL was manufactured in 1995,
roughly 50% of which was used for the production of N-
methylpyrrolidone. The majority of the remaining amount
was 2-pyrrolidone. The world demand for GBL is predicted
to be 120,000 tons by the year 2005. In the United States
and Europe, a major portion of GBL is currently being
produced via the dehydrogenation of 1,4-butanediol, which
is manufactured by the classical Reppe process based on
(
wherein dppb represents diphenylphosphinobutane) pro-
duced the corresponding two isomeric lactones. Moreover,
Bianch (7) has described that some cyclic carboxyric anhy-
drides were hydrogenated in the homogeneous phase us-
ing Ru4H4(CO)8(PBu3)4 as a catalyst to afford the lactones
which did not undergo further hydrogenation.
Though these Ru complex catalysts gave much higher
selectivity for GBL compared to the heterogenous cata-
lysts, they had some problems from a technological view-
1
2 3 3
point. The catalytic activity of RuCl (PPh ) reported
in the literature (5) was low, having a TOF (turnover
To whom correspondence should be addressed. E-mail: 2309180
cc.m-kagaku.co.jp.
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