141
1.4.3 Toluene Alkylation with Methanol to Styrene
The novel route for producing styrene via side-chain toluene alkylation with methanol appears to be a promising alternative technology. The main focus in the past
decades has been on developing suitable catalysts for this reaction. To date, the
model catalyst for the toluene side-chain alkylation has been the Cs-modified zeolite X and has shown good catalytic performance. However, more intense research
is required to develop highly active catalysts for styrene production by toluene sidechain alkylation. The catalytic conversion of toluene achieved until now is still
unsatisfactory due to the difficulty in the activation of the C–H on the toluene side
chain. In future, to achieve the activation of the C-H bond, low valent transition
metal catalysts such as Pd, Rh, and Ru, which are used extensively in the formation
of C–C bond via C–H activation, should be tested for toluene side-chain alkylation
reaction [176–178]. Meanwhile, the work done on composite catalysts for dehydrogenation of MeOH can shed some light on catalyst design and aid in coupling of the
EB dehydrogenation and toluene side-chain alkylation to improve the selectivity to
styrene [179, 180]. Additionally, the use of alternative reactants like formaldehyde
and syngas (CO + H 2 ) can be investigated instead of methanol. Specifically, formaldehyde looks promising as it is an intermediate of methanol dehydrogenation and
could be a potential reactant for enhancing the conversion of toluene and selectivity
to styrene.
Acknowledgments The authors are thankful to the management of Bharat Petroleum Corporation
Limited for granting permission to publish the present chapter.
References
1. Technical background on India BS VI fuel specifications by International Council on Clean
Transportation
2. www.enggcyclopedia.com
3. Hilman IM, Muraza O (2016) Conversion of Isobutylene to Octane-Booster Compounds after
Methyl tert-Butyl Ether Phase out: The Role of Heterogeneous Catalysis. Ind Eng Chem Res
55: 11193–11210
4. Albright LF (2003) Alkylations Industrial, Encyclopedia of Catalysis; Edited by : Howath,
I. T, John Wiley and Sons, New York, Vol. 1, pp 226-281
5. Pryor P (2001). In: Leawood KS (ed) Personal communication. Stratco, Leawood
6. http://www.refinerlink.com/blog/Liquid_Gold_Black_Box/
7. Corma A, Martínez A (1993) Chemistry, catalysts, and processes for isoparaffin-olefin alkylation: actual situation and future trends. Catal Rev Sci Eng 35(4):483–570
8. Boronat M, Viruela P, Corma A (1999) Theoretical study of bimolecular reactions between
carbenium ions and paraffins: the proposal of a common intermediate for hydride transfer,
disproportionation, dehydrogenation, and alkylation. J Phys Chem B 103(37):7809–7821
9. Branzaru J (2001) Introduction to sulfuric acid alkylation unit process design. Stratco, Leawood
10. Hommeltoft SI (2001) Isobutane alkylation—Recent developments and future perspectives.
Applied Catalysis A: General 221, 421–428
Emerging Trends in Solid Acid Catalyst Alkylation Processes
1.4.3 Toluene Alkylation with Methanol to Styrene
The novel route for producing styrene via side-chain toluene alkylation with methanol appears to be a promising alternative technology. The main focus in the past
decades has been on developing suitable catalysts for this reaction. To date, the
model catalyst for the toluene side-chain alkylation has been the Cs-modified zeolite X and has shown good catalytic performance. However, more intense research
is required to develop highly active catalysts for styrene production by toluene sidechain alkylation. The catalytic conversion of toluene achieved until now is still
unsatisfactory due to the difficulty in the activation of the C–H on the toluene side
chain. In future, to achieve the activation of the C-H bond, low valent transition
metal catalysts such as Pd, Rh, and Ru, which are used extensively in the formation
of C–C bond via C–H activation, should be tested for toluene side-chain alkylation
reaction [176–178]. Meanwhile, the work done on composite catalysts for dehydrogenation of MeOH can shed some light on catalyst design and aid in coupling of the
EB dehydrogenation and toluene side-chain alkylation to improve the selectivity to
styrene [179, 180]. Additionally, the use of alternative reactants like formaldehyde
and syngas (CO + H 2 ) can be investigated instead of methanol. Specifically, formaldehyde looks promising as it is an intermediate of methanol dehydrogenation and
could be a potential reactant for enhancing the conversion of toluene and selectivity
to styrene.
Acknowledgments The authors are thankful to the management of Bharat Petroleum Corporation
Limited for granting permission to publish the present chapter.
References
1. Technical background on India BS VI fuel specifications by International Council on Clean
Transportation
2. www.enggcyclopedia.com
3. Hilman IM, Muraza O (2016) Conversion of Isobutylene to Octane-Booster Compounds after
Methyl tert-Butyl Ether Phase out: The Role of Heterogeneous Catalysis. Ind Eng Chem Res
55: 11193–11210
4. Albright LF (2003) Alkylations Industrial, Encyclopedia of Catalysis; Edited by : Howath,
I. T, John Wiley and Sons, New York, Vol. 1, pp 226-281
5. Pryor P (2001). In: Leawood KS (ed) Personal communication. Stratco, Leawood
6. http://www.refinerlink.com/blog/Liquid_Gold_Black_Box/
7. Corma A, Martínez A (1993) Chemistry, catalysts, and processes for isoparaffin-olefin alkylation: actual situation and future trends. Catal Rev Sci Eng 35(4):483–570
8. Boronat M, Viruela P, Corma A (1999) Theoretical study of bimolecular reactions between
carbenium ions and paraffins: the proposal of a common intermediate for hydride transfer,
disproportionation, dehydrogenation, and alkylation. J Phys Chem B 103(37):7809–7821
9. Branzaru J (2001) Introduction to sulfuric acid alkylation unit process design. Stratco, Leawood
10. Hommeltoft SI (2001) Isobutane alkylation—Recent developments and future perspectives.
Applied Catalysis A: General 221, 421–428
Emerging Trends in Solid Acid Catalyst Alkylation Processes