Chapter 6
Conversion of Methane to Aromatic
Hydrocarbons
6.1 Introduction
Aromatic hydrocarbons such as benzene are important for the production of polymers
and raw materials for chemical manufacturing. Benzene is usually produced via the
catalytic reforming of naphtha, which yields a mixture of benzene, toluene, and the
xylenes (BTX). Benzene is also a volatile byproduct of the conversion of coal to
coke. Benzene from coke over distillate is available only to the extent that coke is
required by the steel industry.
As discussed in Chap. 5, the oxidative coupling of methane, i.e., the direct conversion of methane with the assistance of oxidants such as O 2 , is more thermodynamically favorable than the non-oxidative conversion of methane to hydrocarbons.
Unfortunately, the presence of oxygen can cause over-oxidation of the hydrocarbons
to CO 2 and CO.
However, aromatic hydrocarbons such as benzene can be produced by the direct
conversion of methane in the absence of oxygen, as mentioned in Chap. 5. For example, at high reaction temperatures (~1300 K), Fe (0.5 wt%)/SiO 2 catalysts selectively
produce ethylene and aromatic hydrocarbons such as benzene without the production
of CO 2 and CO under non-oxidative reaction conditions. The maximum methane conversion was 48.1% at 1363 K, with a hydrocarbon yield of 48% [1]. This reaction is
often known as “dehydrocyclization”, “aromatization”, or “dehydroaromatization”.
For the purpose of this chapter, the conversion of methane to aromatic hydrocarbons
will be referred to as the “methane dehydroaromatization” (MDA) reaction.
The conversion of methane to benzene (C 6 H 6 ) is stoichiometrically expressed in
reaction (6.1); as shown, nine moles of hydrogen (H 2 ) are produced along with each
mole of benzene.
6 CH 4
C 6 H 6 + 9 H 2
(6.1)
© Springer Nature Singapore Pte Ltd. 2020
T. Baba and A. Miyaji, Catalysis and the Mechanism of Methane Conversion to Chemicals,
https://doi.org/10.1007/978-981-15-4132-2_6
127
Conversion of Methane to Aromatic
Hydrocarbons
6.1 Introduction
Aromatic hydrocarbons such as benzene are important for the production of polymers
and raw materials for chemical manufacturing. Benzene is usually produced via the
catalytic reforming of naphtha, which yields a mixture of benzene, toluene, and the
xylenes (BTX). Benzene is also a volatile byproduct of the conversion of coal to
coke. Benzene from coke over distillate is available only to the extent that coke is
required by the steel industry.
As discussed in Chap. 5, the oxidative coupling of methane, i.e., the direct conversion of methane with the assistance of oxidants such as O 2 , is more thermodynamically favorable than the non-oxidative conversion of methane to hydrocarbons.
Unfortunately, the presence of oxygen can cause over-oxidation of the hydrocarbons
to CO 2 and CO.
However, aromatic hydrocarbons such as benzene can be produced by the direct
conversion of methane in the absence of oxygen, as mentioned in Chap. 5. For example, at high reaction temperatures (~1300 K), Fe (0.5 wt%)/SiO 2 catalysts selectively
produce ethylene and aromatic hydrocarbons such as benzene without the production
of CO 2 and CO under non-oxidative reaction conditions. The maximum methane conversion was 48.1% at 1363 K, with a hydrocarbon yield of 48% [1]. This reaction is
often known as “dehydrocyclization”, “aromatization”, or “dehydroaromatization”.
For the purpose of this chapter, the conversion of methane to aromatic hydrocarbons
will be referred to as the “methane dehydroaromatization” (MDA) reaction.
The conversion of methane to benzene (C 6 H 6 ) is stoichiometrically expressed in
reaction (6.1); as shown, nine moles of hydrogen (H 2 ) are produced along with each
mole of benzene.
6 CH 4
C 6 H 6 + 9 H 2
(6.1)
© Springer Nature Singapore Pte Ltd. 2020
T. Baba and A. Miyaji, Catalysis and the Mechanism of Methane Conversion to Chemicals,
https://doi.org/10.1007/978-981-15-4132-2_6
127