Carbonylation of methanol with carbon monoxide in the presence of sulfur-containing catalysts

Article abstract of DOI:10.1023/A:1015516923305

Physicochemical features of methanol carbonylation with carbon monoxide catalyzed with sodium sulfides Na₂S_x (x = 1, 2, 4) were studied. The effect of admixtures of sulfur dioxide in the gas phase on the yield of the target product (methyl formate) was revealed.

Full text of DOI:10.1023/A:1015516923305

Russian Journal of Applied Chemistry, Vol. 75, No. 1, 2002, pp. 68 70. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 1,
002, pp. 67 70.
Original Russian Text Copyright
2
2002 by Aleksandrov, Shekunova, Kolmakov, Tarasov.
CATALYSIS
Carbonylation of Methanol with Carbon Monoxide
in the Presence of Sulfur-containing Catalysts
Yu. A. Aleksandrov, V. M. Shekunova, A. O. Kolmakov, and E. H. Tarasov
Research Institute of Chemistry, Lobachevskii Nizhni Novgorod State University, Nizhni Novgorod, Russia
Received June 25, 2001
Abstract Physicochemical features of methanol carbonylation with carbon monoxide catalyzed with sodium
sulfides Na S (x = 1, 2, 4) were studied. The effect of admixtures of sulfur dioxide in the gas phase on the
2
x
yield of the target product (methyl formate) was revealed.
Methanol is a versatile intermediate, which can be
used in syntheses of various chemical substances by
the reaction with carbon monoxide or synthesis gas
The catalytic activity of sodium sulfide in car-
bonylation of methanol with carbon monoxide de-
pends on the solvent (Table 2). This reaction proceeds
most easily in neat methanol or in aromatic hydrocar-
bons (benzene, toluene). The yield of methyl formate
[
1]. Some of such syntheses are performed on the
commercial scale, e.g., production of acetic acid by
catalytic carbonylation of methanol using complex
rhodium homogeneous catalyst. It is well known [2]
that base catalysts effect formation of methyl formate
by reaction of carbon monoxide with methanol at
elevated pressure:
at the constant Na S : methanol ratio increases with
2
increasing methanol concentration in benzene from
1
.3 to 5.0 M. The further growth of the methanol con-
centration up to pure methanol does not increase the
methyl formate yield. The above results can be ex-
plained by variation of the solvent polarity and CO
solubility in the solvent.
Cat.
CH OH + CO
HCO CH .
(1)
3
2
3
Water added to methanol even in small amounts
Methyl formate is formed in a high yield with
sodium methylate as catalyst. However, metallic sodi-
um is required for the synthesis of this catalyst, which
restricts its use.
(
0.2 0.4 M) noticeably inhibits the reaction and prac-
tically stops it at concentrations higher than 0.9 M
Table 3). This effect is probably caused by deactiva-
tion of the catalyst due to its shielding by the hydrate
shell.
(
It was shown previously [3, 4] that sulfur-contain-
ing catalysts can be used for the synthesis of urethanes
by carbonylation of aromatic nitro compounds with
carbon monoxide in methanol.
Table 1. Activity of sulfur-containing catalysts in car-
bonylation of methanol with carbon monoxide* (1 h, tem-
perature 80 C, CO pressure 15 MPa)
The goal of this work was to study carbonylation
of methanol with carbon monoxide in the presence of
sulfur-containing catalysts.
Catalyst
Cc, M
Y , % Pc, g l 1 h 1
mf
Sodium sulfides Na S with x = 1, 2, 4, which are
relatively available and cheap commercial products,
were used as catalysts.
2
x
Na2S
0.3
80
90
95
10
8
89
85
85
1190
1338
1396
146
0
.6
1.2
0.6
0.6
Na2S2
Na2S4
As seen from Table 1, anhydrous sodium monosul-
fide is the most active catalyst. With increasing its
concentration within the 0.3 1.2 M range, the yield of
the target product (methyl formate) increases to 95%.
As opposed to nitrobenzene carbonylation [5], V(V)
compounds, pyridine, or polyethylene glycol added as
activators of sulfur-containing catalysts did not in-
crease the methyl formate yield.
117
Na S : KVO3
0.6 : 0.06
0.6 : 0.6
1323
1260
1266
2
Na S : pyridine
2
Na S : polyethylene 0.6 : 0.6
2
glycol
*
Y
is the yield of methyl formate; P is the catalyst per-
mf c
formance.
1
070-4272/02/7501-0068$27.00 2002 MAIK Nauka/Interperiodica

CARBONYLATION OF METHANOL WITH CARBON MONOXIDE
69
Table 2. Effect of solvent on carbonylation of methanol with carbon monoxide in the presence of sodium sulfide*
(
1 h, temperature 80 C, CO pressure 10 MPa)
Solvent , M
C
K
,** %
S,** %
Y , %
Pc, g l 1 h 1
CH OH
CH OH
mf
3
3
2
4.8
5.0
5.0
5.0
5.0
5.0
5.0
1.3
94
0
1
90
0
85
0
1
1266
0
CCl4
Dioxane
Ethyl acetate
Chlorobenzene
THF
80
29
80
90
85
69
77
89
88
3
79
227
227
241
34
91
251
466
94
96
86
97
71
80
96
94
27
77
77
82
49
62
86
84
Toluene
Benzene
2
5
9
.5
.0
.9
*
Molar ratio Na S : methanol = 0.024; the same for Tables 4 and 5.
2
*
* K
is the methanol conversion; S is the selectivity with respect to methyl formate.
CH OH
3
The effect of the CO pressure on the methanol car-
Table 3. Effect of water on carbonylation of methanol
with carbon monoxide in the presence of sodium sulfide*
(1 h, temperature 80 C, CO pressure 10 MPa)
bonylation in benzene in the presence of sodium sul-
fide was also studied (Table 4). As the CO pressure is
increased from 3 to 7 Mpa, the methyl formate yield
grows substantially, but it does not appreciable grow
further at the pressure of about 15 MPa.
1
C
, M
Y , %
Pc, g l h 1
H O
mf
2
0
0.4
0.9
.2
85
69
1
1266
1024
The carbonylation rate noticeably increases with
the CO pressure. For instance, at the CO pressure of
0 MPa the methyl formate yield in 10 min is the
same as in 60 min at 7 MPa; in 10 min at 7 MPa the
yield is lower by half.
14
1
7
.8
.4
Traces
0
Not determined
0
1
*
Initial concentration of Na S 0.6 M.
2
The temperature also affects the methanol car-
bonylation with CO (Table 5). The maximal yield is
observed at 80 C. At lower temperatures, the reaction
is too slow. At higher temperatures, the methyl for-
mate yield also decreases probably because of low
thermal stability of the intermediate participating in
the catalytic step; both methanol conversion and reac-
tion selectivity with respect to methanol decrease.
Table 4. Catalytic carbonylation of methanol in benzene
at various CO pressures and 80 C
PCO
MPa
,
,
K
S,
Y ,
P ,
CH OH,
mf
c
3
min
%
%
%
g l 1 h 1
3
5
7
10
5
60
60
60
60
60
10
10
65
89
95
96
98
59
96
76
86
88
89
92
80
86
49
77
84
86
90
42
82
144
226
247
251
263
735
1442
The above results suggest the following scheme of
the catalytic carbonylation of methanol with CO:
1
Na
7
10
.
.
.
CH OH + Na S
CH O
S Na
.
3
2
3
.
.
H
Table 5. Catalytic carbonylation of methanol with carbon
monoxide in benzene (1 h, CO pressure 10 MPa)
A
Na
.
Pc, g l h 1
1
.
T,
C
Y , %
CO
.
mf
CH O
S Na
CH ONa + NaSH
3
3
.
.
.
6
0
62
85
71
21
183
251
209
62
.
H
.
80
100
80
.
O=C
B
1
HCOOCH3 + Na S.
(2)
2
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 75 No. 1 2002

70
ALEKSANDROV et al.
Table 6. Effect of SO on methanol carbonylation with
carbon monoxide in the presence of sodium sulfide* (0.5 h,
Carbonylation of methanol was performed in a
stainless steel (KhM-18) 50 cm autoclave charged
2
3
8
0 C, CO pressure 10 MPa)
with the calculated amounts of methanol and catalysts.
The autoclave was purged with carbon monoxide at
continuous agitation of the reaction mixture. After that
CO was pumped to a pressure of 6 10 MPa. Then the
temperature of the experiment, which was monitored
with a thermometer inserted into the body of the auto-
clave, and the required pressure were set. This instant
was taken as the reaction start. The reaction process
was monitored by the pressure decrease. After the
reaction completion, the autoclave was cooled, and the
pressure was relieved. Liquid reaction products were
analyzed by GLC on a Tsvet-101 chromatograph with
a thermal conductivity detector. Helium was used as
CSO2, vol %
0
PSO2, MPa
Y , %
mf
0
97
97
50
25
Traces
0
1
1
5
.72
.05
.30
.61
0.06
0.09
0.11
0.49
*
Initial Na S concentration 1.2 M.
2
Methanol forms hydrogen-bonded intermediate A
with sodium sulfide and then A reacts with CO to
form intermediate B. The latter rearranges through
sodium methylate and hydrosulfide and converts into
methyl formate with regeneration of sodium sulfide.
In addition, A can decompose with formation of sodi-
um methylate and sodium hydrosulfide.
3
1
a carrier gas (flow rate 30 cm min ); 3000 3 mm
glass column was used; stationary phase PEG 1500,
temperature 60 C.
CONCLUSION
Saturation observed with increasing the methanol
concentration in the solvent (Table 2) and the effect of of carbonylation of methanol with carbon monoxide.
Anhydrous sodium sulfide is the effective catalyst
the temperature on the target product yield (Table 5)
confirm formation of intermediate B. Inhibition of the
reaction by water is explained by blocking of the
active centers of the catalyst by the hydrate shell. It is
well known [6] that small admixtures of sulfur com-
pounds in exhaust gases deactivate many catalytic
systems. Therefore, we studied the effect of acidic
gaseous admixtures, in particular, sulfur dioxide,
which are present together with CO in exhaust gases
of metallurgic, heat and power, and other plants and
can affect carbonylation of methanol with carbon
monoxide.
Sulfur dioxide as an admixture in CO deactivates
the reaction.
REFERENCES
1. Sheldon, R.A., Chemicals from Synthesis Gas: Catalyt-
ic Reactions of CO and H , Dordrecht: Reidel, 1983.
2
2. Tagaev, O.A., Gashchuk, M.D., Padzerskii, Yu.A., and
Moiseev, I.I., Izv. Akad. Nauk SSSR, Ser. Khim., 1982,
no. 11, p. 2638.
3. Bordzilovskii, V.Ya., Redoshkin, B.A., Gerega, V.F.,
et al., Zh. Prikl. Khim., 1984, vol. 57, no. 2, pp. 360
3
63.
The initial SO2 concentration in the gas mix-
ture was varied within the 0 5.61 vol % range
4
5
. Redoshkin, B.A., Bordzilovskii, V.Ya., Gerega, V.F.,
et al., Zh. Prikl. Khim., 1984, vol. 57, no.3, pp. 600
(
1
Table 6). As seen, at an SO content from 0.72 to
.30 vol % carbonylation of methanol is inhibited, and
2
6
02.
. Kolmakov, A.O., Shekunova, V.M., and Aleksand-
rov, Yu.A., Zh. Obshch. Khim., 1998, vol. 68, no. 8,
p. 1405.
at 5.61 vol % it completely stops.
EXPERIMENTAL
6
7
8
. Sokolovskii, V.D., Yur’eva, T.M., Matros, Yu.Sh.,
et al., Usp. Khim., 1989, vol. 18, no. 1, pp. 5 37.
Anhydrous Na S was prepared by dehydration of
2
. Klyuchnikov, N.G., Neorganicheskii sintez (Inorganic
Synthesis), Moscow: Prosveshchenie, 1983.
Na S 9H O [7]. Na S and Na S were synthesized
2
2
2 2
2 4
by fusion of anhydrous Na S with stoichiometric
2
. Handbuch der praparativen anorganischen Chemie,
amounts of chemically pure grade sulfur [8].
Brauer, G. von, Ed., Stuttgart: Enke, 1978.
CO and SO were used without additional purifica-
2
9. Organic Solvents. Physical Properties and Methods of
Purification, Weissberger, A., Proskauer, E.S., Rid-
dick, J.A., and Toops, E.E., Eds., New York: Inter-
science, 1955.
tion. Methanol, benzene, toluene, dioxane, tetrahydro-
furan, chlorobenzene, ethyl acetate, and carbon tetra-
chloride were purified by common procedures [9].
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 75 No. 1 2002