Conversion of ethanol to gasoline range hydrocarbons using a
zeolite catalyst (HZSM-5)
The investigation of alternative and renewable sources of fuel is
of special interest to countries lacking petroleum reserves. Some
years ago, a project in the Department of Chemistry focussed on
the conversion of ethanol to petrol by the use of the synthetic
A related process, which uses methanol as substrate (obtained by
converting methane from natural gas) has been developed to
industrial scale in New Zealand and has the capacity to supply
about one third of their petrol requirements.
Our study was concerned with catalyst design for the conversion
of ethanol with regard to the manufacture of liquid and gaseous
HZSM-5 can be considered as a derivative of silica and alumina,
both very cheap reagents. It acts as a solid acid since for each
Al3+ substituted for Si4+ in the structure,
an H+ ion is also needed to maintain the overall
neutrality of the molecule.
The 3-D lattice built up, consists of channels through which
certain small molecules can pass and react inside by a process
called shape selectivity. Bulky molecules can not enter the
channels and reaction of smaller molecules to larger ones is
hindered by the size of the channels, Figure 1.
This restriction means that only molecules with less than say 10
carbons are produced in the reactions inside the catalyst.
Our results indicate total conversion of the ethanol and the
liquid fuel produced is comparable to commercial unleaded grade
petrol with a good range of aromatic and aliphatic hydrocarbons,
The hydrocarbons were identified by GC and GC/MS analysis.
A simulation of a GC/MS
showing spectra and molecular graphics is available using JSpecView and Jmol.
Table 1. The major peaks identified in Synfuel
||m- and p-xylene
In addition, other potential catalysts, including substituted
aluminophosphates, have been prepared and characterised by X-ray
powder techniques, scanning electron microscopy, FTIR, magic
angle NMR and neutron activation analysis.
These materials have been shown to be more useful for conversion
of ethanol to gaseous products such as ethylene.
Their reactions with ethanol have significant potential for the
production of petrochemicals.
For more information on the methanol to gasoline (MTG) process see the pages at
Table 2. Comparison of HZSM5 sample CI1/C/H and Mobil's
MZIIO used in the catalytic conversion of EtOH a.
|Distribution of conversion products (wt%)
|Distribution of total hydrocarbons (wt %):
|Selectivity within permanent gases (wt%)
|Selectivity for aromatics in C5+ (wt%)
|Nonaromatics in C5+
|m- and p-Xylene
a Reactor temperature: 3750C,
WHSV:6.48hr-1, N2 flow rate: 20cm3/min, wt of
Included in the non-aromatic hydrocarbons are:
dimethyl (cyclo) pentanes, methylcyclopentane, ethylcyclopentane
and di- and trimethylbutanes, etc.
For the answers to some frequently answered questions on
gasoline, oxygenates etc., see FAQS.ORG.
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Lancashire, all rights reserved.
Created and maintained by Prof. Robert J.
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica.
Created Feb 1995. Links checked and/or last
modified 26th November 2013.