Reaction of dimethyl disulfide with thiophene catalyzed by zeolite

Article abstract of DOI:10.1134/S1070428015020141

Reaction of dimethyl disulfide with thiophene under the action of highly siliceous zeolite at 180-350°C and contact time 0.6-14 s resulted in formation of thioalkylation products, 2-(methylsulfanyl)- and 2,5-bis(methylsulfanyl)thiophenes and also alkylate

Full text of DOI:10.1134/S1070428015020141

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2015, Vol. 51, No. 2, pp. 217–220. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © A.V. Mashkina, L.N. Khairulina, 2015, published in Zhurnal Organicheskoi Khimii, 2015, Vol. 51, No. 2, pp. 229–231.
Reaction of Dimethyl Disulfide with Thiophene
Catalyzed by Zeolite
A. V. Mashkina and L. N. Khairulina
Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences,
pr. Akademika Lavrent’eva 5, Novosibirsk, 630090 Russia
e-mail: amash@catalysis.ru
Received June 6, 2014
Abstract—Reaction of dimethyl disulfide with thiophene under the action of highly siliceous zeolite at 180–
3
50°С and contact time 0.6–14 s resulted in formation of thioalkylation products, 2-(methylsulfanyl)- and 2,5-
bis(methylsulfanyl)thiophenes and also alkylated derivatives, 2-methyl-, 2,5-dimethyl-, and 2,3,4-trimethyl-
thiophenes.
DOI: 10.1134/S1070428015020141
*
(
Alkylsulfanyl)thiophenes
may be used as
basic sites of the zeolite leading to the rupture of the
additives to lubricating oils and polymers to improve
their thermooxidative stability, in the synthesis of
herbicides and electroconducting materials [1]. One of
the procedures for the preparation of (alkylsulfanyl)
thiophenes is the reaction of dialkyl disulfides with
thiophene. In [2–4] the reaction of dimethyl disulfide
with thiophene was investigated catalyzed with zinc or
manganese chlorides applied on the montmorillonite
support. In chlorobenzene (80–150°С, 8–48 h, molar
ratio disulfide–thiophene 8 : 1) in argon the thiophene
conversion was 35–50%, and 2,3,4-, 2,3,5-tris-
S–S and C–S bonds and to the formation of CH S and
3
CH fragments undergoing further transformations [8].
3
It was expectable that in the reaction of dimethyl
disulfide with thiophene zeolite HZSM-5 would
exhibit a high catalytic activity which would result in
of the polysubstituted thiophene derivatives.
We investigated the reaction of dimethyl disulfide
with thiophene in helium atmosphere and at normal
pressure varying the temperature (180–350°С), the
contact time, and the molar ratio of reagents.
(
(
methylsulfanyl)thiophenes and 1,2,3,4-tetrakis-
methylsulfanyl)thiophene were obtained. The reaction
We carried out separate experiments with individual
dimethyldisulfide and thiophene (180–350°С, contact
time 0.7–3.6 s, initial concentration of dimethyl
disulfide 4–5 vol %, of thiophene, 1.4–1.6 vol %).
Dimethyl disulfide under these conditions readily
decomposed giving methanethiol, dimethyl sulfide,
hydrogen sulfide, dimethyl tri- and -tetrasulfides,
carbon disulfide, and ethylene. The increase in the
temperature and contact time resulted in growing
conversion of the dimethyl disulfide; the yields of
dimethyl tri- and -tetrasulfides decreased, and of the
other products, increased. Some decomposition of
thiophene was observed only at the temperature over
carried out at pressure and when adding some air to
argon (150°С, 5 h) along with tri-and tetra-substituted
thiophenes provided also a small quantity of 2,5-bis-
(
methylsulfanyl)thiophene.
In this study in order to obtain mainly mono- and
bis(methylsulfanyl)thiophenes the reaction between
dimethyl disulfide and thiophene was carried out in the
presence of highly siliceous zeolite HZSM-5. On the
surface of this catalyst a large number of strong proton
sites is present, and also strong Lewis acid centers and
basic sites of a moderate strength [5]. The mentioned
sites may activate the reagents. Contacting with the
zeolite, like in the acid solution, thiophene is
protonated with the formation of a thiophenium ion [6,
3
00°С: its conversion was 3–10%, hydrocarbons С –С
1 2
formed in 1.5–4.0 mol % yield, the obtained high
boiling compounds were not identified.
7
]. Dimethyl disulfide is coordinated with the acid and
The experiments on conversion of the mixture of
dimethyl disulfide with thiophene were carried out at
*
Formerly named (alkylthio)thiophenes.
2
17

2
1
18
MASHKINA, KHAIRULINA
80–350°С, contact time 0.6–14 s, molar ratio disul-
dimethyl disulfide with thiophene were somewhat
lower than at the decomposition of individual dimethyl
disulfide. The decrease in the conversion and the
yields of products originates from the reduced active
surface of the catalyst where a part of the sites is
occupied by the chemosorbed thiophene.
fide–thiophene 2–7.8 : 1. Under these conditions thio-
alkylation products were obtained: 2-(methylsulfanyl)-
thiophene and 2,5-bis(methylsulfanyl)thiophene, and
also alkylation products: 2-methylthiophene, 2,5-dime-
thylthiophene, and 2,3,4-trimethylthiophene, not found
previously in [2–4]. Dimethyl disulfide unreacted with
thiophene trans-formed in the same products as at the
decomposition of the individual disulfide.
The thiophene conversion in the runs with the
mixture with dimethyl disulfide grew with the growing
temperature. For instance, at the contact time 2.3–2.5 s
and the molar ratio of the reagents 4–5 : 1 at the
temperature 180, 200, 250, 300, and 350°С the
conversion reached 14, 16, 22, 31, and 43% respec-
tively.
The conversion of dimethyl disulfide in the mixture
with thiophene at a relatively low temperature was
considerably smaller then the conversion of dimethyl
disulfide without thiophene; the conversion grew with
the growing temperature For instance, at the contact
time 1.2 s and the molar ratio disulfide–thiophene 4–
The yield of thiophene derivative depended on the
reaction conditions, some results are compiled in the
table. At increasing molar ratio dimethyl disulfide–
thiophene the conversion of thiophene and the
products yields somewhat grew. In various conditions
the yield of 2-(methylsulfanyl)thiophene was ~1.5–
5
: 1 the conversion of dimethyl disulfide was as
follows, %:
Temperature, °С
180
18
200 250 300 350
Dimethyl disulfide
Dimethyl disulfide,
mixture with thiophene
37
75
84
92
3
times higher that the yield of 2,5-bis(methylsulfanyl)
5
14
25
60
90
derivative. The yields of mono- and trimethylthio-
phenes were close, and the yield of 2,5-dimethylthio-
phene was significantly lower. The overall yield of the
The yields of methanethiol, dimethyl sulfide, and
hydrogen sulfide in the runs with the mixture of
Table. Effect of conditions on thiophene conversion and yields of products of thioalkylation and alkylation. Catalyst HZSM-5,
molar ratio dimethyl disulfide–thiophene, 4–5 : 1
Yield, mol %
Thiophene
conversion, %
Thioalkylation products
-(methylsulfanyl)- 2,5-bis(methyl-
Alkylation products
2,5-dimethyl- 2,3,4-trimethyl-
Contact time, s
2
2-methyl-
thiophene
sulfanyl)thiophene thiophene
Temperature 180 С
thiophene
thiophene
о
1
2
4
5
4
8
1
.2
.3
.9
.0
.9
.8
7
14
19
17
26
28
42
3.2
5.3
7.1
7.7
9.2
10.4
17
2.0
4.5
5.0
3.7
5.5
7.1
11.0
0.3
1.7
3.3
2.7
4.8
4.4
6.0
0.1
0.3
0.7
0.7
2.2
0.6
1.8
1.5
2.2
3.0
2.0
4.0
3.8
5.0
а
b
4.0
о
Temperature 300 С
0
.6
14
24
20
35
31
42
51
1.3
2.0
2.1
4.2
1.6
1.3
0.7
1.0
2.5
3.4
0.5
0.4
0.2
7
1.5
2.0
1.4
3.0
6.0
9.0
12
4.5
9.0
5.3
10
1
1
1
2
4
8
.2
.2
.2
.3
.9
.5
10
а
8
b
14
13
16
19
10
12
1.1
18
а
b
Molar ratio dimethyl disulfide–thiophene: 2.0–2.2, 7.4–7.8.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 2 2015

REACTION OF DIMETHYL DISULFIDE WITH THIOPHENE CATALYZED BY ZEOLITE
219
+
SCH3
CH3
H CS
SCH3
H C
3
S
S
+
(CH ) S
3 2 2
CH3
CH3
3
S
+
+
H C
3
CH3
S
S
S
thioalkylation products at the relatively low
temperature exceeded the yield of the alkylation
products. At high temperature the yield of the
thioalkylation products was low, mainly the alkyl-
substituted thiophenes were obtained (see the scheme).
EXPERIMENTAL
We used as catalyst an industrial sample of highly
siliceous zeolite HZSM-5 in a hydrogen form (SiO
/
2
2
Al O = 34) (Ssp 500 m /g) calcined before use in a
2 3
stream of dry air for 5 h at 530°С. The substances used
The process results were affected by the contact
time. At the constant temperature and reagents
concentration the thiophene conversion grew with the
contact time. At the low temperature with the growing
contact time both yields of thioalkylation and
alkylation products of thiophene increased. At the high
temperature the thioalkylation products formed in a
low yield, and it decreased with the growing contact
time, and the yields of the thiophene alkylation
products increased, but insignificantly. At various
temperatures the overall selectivity of thiophene
derivatives formation at varying the thiophene
conversion was approximately constant (see the
figure).
in the study were reagents of “pure” grade.
The catalysis experiments were carried out at
atmospheric pressure in a flow reactor with a fixed
catalyst bed, catalyst grains of 0.25–0.5 mm, under
conditions excluding diffusion difficulties. Each run
was performed with the use of fresh catalyst. The
system was totally under temperature control. Into the
saturators filled with dimethyl disulfide and thiophene
placed in thermostats helium was passed from a gas
cylinder. After mixing the gas saturated with dimethyl
disulfide and thiophene was passed into the reactor
with catalyst heated at the desired temperature. The gas
sampling was carried out every 45 min within ~2 h. The
high boiling products were condensed in a cooled
receiver.
This suggests that the reactions proceed by two
independent routes.
Reaction products were identified by GC-MS on an
instrument Agilent 7000 GC/MS Triple Quad equip-
ped with a capillary column (30 m × 0.25 mm),
stationary phase HP-5MS. The quantitative analysis
was carried out on a chromatograph LKhM-8MD
equipped with a katharometer, column 2 m × 3 mm,
stationary phase XE-60 on Chromaton AW-LMCS,
carrier gas helium. Contact time is equal to the ratio of
the catalyst volume (cm ) to the gas flow rate (cm /s)
at room temperature and atmospheric pressure. The
conversion of thiophene and dimethyl disulfide, and
also the yields of the reaction products were calculated
from the concentration of the formed product with
respect to the initial concentration of the substarte
The maximum selectivity of (methylsulfanyl)-
thiophenes formation was attained at the temperature
below 200°С and was ~70%, at higher temperature it
decreased. This was due to decomposition of СН3S
fragments at raising the temperature [9–11]. The
arising increased amount of СН fragments results in
3
the growing formation of methylthiophenes whose
overall formation selectivity attains 90%.
3
3
о
3
1
00 С
1
00
4
о
80 С
1
6
2
0
0
(
mol %), and the selectivity of product formation was
о
1
3
80 С
evaluated from the ratio of its yield to the substrate
conversion.
3
о
00 С
2
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1
0
20
30
40
50
Thiophene conversion, %
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2
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