Indian Journal of Chemistry
Vol. 51A, Sept-Oct 2012, pp. 1252-1262
Carbon dioxide utilisation
Carbon dioxide – A potential raw material for the production of fuel,
fuel additives and bio-derived chemicals
Sivashunmugam Sankaranarayanan & Kannan Srinivasan*
Discipline of Inorganic Materials and Catalysis, CSIR-Central Salt and Marine Chemicals Research Institute,
Gijibhai Bhadheka Marg, Bhavnagar 364 002, India
Email: [email protected]/ [email protected]
Received 12 July 2012; revised and accepted 18 August 2012
Amongst the various greenhouse gases emitted into the atmosphere, carbon dioxide emission is the highest in terms of
tonnage and has been identified as a predominant source contributing to climate change. Owing to its abundance through
anthropogenic sources, it is highly desirable to utilize CO2 to produce valuable products, in particular fuels and large volume
chemicals, and thereby mitigate significantly its environmental impact. This review aims to cover the attempts made in
utilizing CO2 for the production of fuels, fuel additives and bio-derived chemicals, in particular organic carbonates.
Although this review does not intend to encompass the literature in the holistic manner, it does endeavor to provide recent
approaches, difficulties, challenges and offer perspective in the years to come on this important area of research.
Keywords: Carbon dioxide utilization, Raw material for fuel production, Syngas, Methane, Dimethyl carbonate, Fatty
cyclic carbonate, Glycerol carbonate
Carbon dioxide (CO2) is a greenhouse gas and occupies
the top position (more than 80 % in terms of amount
for USA) in the overall emissions amongst other gases
such as carbon monoxide (CO), methane (CH4),
chlorofluorocarbons (CFC’s), etc. Increase in the
emission of greenhouse gases makes significant
climate changes and will lead to consecutive effects
such as increase in global temperature and changes in
wind patterns. China occupies the top position in CO2
emissions with 24 % of world emissions, followed by
United States (18 %), while India contributes around
5 %.1 Longer estimated life time of CO2 in
the atmosphere (50-200 years) and a profound surge
in the human related emissions in recent decades
cause serious concerns on its emission and impact
on the environment.
Sources of CO2 emissions can be broadly classified
into three categories, namely, stationary, mobile and
natural sources. Generally, industrial emissions
belong to stationary sources, emissions from vehicles
are classified as mobile sources, and emission from
volcano are natural sources.2 Figure 1 shows the
different anthropogenic sources of CO2 and their sinks
(based on 2010 data).3 Burning of fossil resources
such as petroleum and coal contributes significantly to
CO2 emission whose rate are estimated at 22.29 and
24.65 kg C/GJ, respectively.4 According to the
International Energy Outlook 2011, world’s energy
related CO2 emission is estimated to increase from
30.2 billion metric tons (BMT) in 2008 to 35.2 and
43.2 BMT in 2020 and 2035 respectively.5
In the current scenario, decreasing the CO2 amount
in the atmosphere is the biggest challenge and needs
new ideas and technologies. Possible ways to reduce
the CO2 concentration in the atmosphere are using
renewable fuels instead of fossil fuels and by
converting the emitted CO2 into useful products by
chemical transformations. Although sincere efforts
are being made for replacing fossil fuels by renewable
energy,6 there are several practical difficulties and
limitations. Although a single solution is not going to
Fig. 1 − Anthropogenic sources of CO2 and their sinks.
SIVASHUNMUGAM & KANNAN: CO2 AS POTENTIAL RAW MATERIAL FOR FUEL PRODUCTION
solve such a mega problem, an alternative approach to
reduce CO2 emission is by its value addition to
produce large quantities of useful products. Such an
approach would also create new opportunities that are
hitherto not realized or known.
High abundance and low cost are the
main advantages of CO2 as a promising feedstock
in organic synthesis.7,8 CO2 is an interesting
C1 building block and can be an apt replacement
for hazardous molecules like phosgene in many
industrial processes. Efforts have been made to
utilize CO2 in commercial applications such as food
processing and carbonated beverages. In recent
years, CO2 has attracted the attention of chemical
industries as it can be categorized as a sustainable raw
material that can be used to produce diverse products
through a variety of chemical transformations.
Despite such practices, currently in industries, only
110 million metric tons (MMT) of CO2 are used for
chemical transformation which is less than 1 % of
global emissions.9
Sakakura et al.10 categorized a variety of reactions
using CO2 as a potential starting material resulting in
many products. Figure 2 summarizes the possible
reactions and some important chemicals derived using
CO2. Production of chemicals like urea and
carbonates using CO2 is well-known and has been
commercialised. Besides chemicals, energy products
from CO2 would make a considerable impact on its
emission. The worldwide requirement of fuels is
nearly two orders of magnitude higher than that of
chemicals. CO2 emission can be effectively reduced
Fig. 2 − Possible reactions and important chemicals from CO2.
1253
by its utilization as a source for fuel production. This
will be advantageous not in terms of value but also in
significantly curbing its emission, which in turn will
mitigate greenhouse effect.
Utilization of biomass for energy and chemical
production is an active research domain currently
pursued all over the world because of its ecological
and economic gains.11 CO2 is also gaining
significance in the biorefining processes of biomass to
value-added bio-derived chemicals. Herein, recent
attempts in the use of CO2 as a raw material for fuel,
fuel additives and bio-derived chemicals, in particular
organic carbonates is reviewed (Fig. 3).
CO2 for the Production of Fuels
Products obtained from CO2 have applications as
fuels and fuel additives. Figure 4 shows the schematic
representation of
production of fuel and fuel
additives from CO2. Carbon dioxide is in the highly
oxidized form, and hence reduction process is largely
applicable to produce fuel and fuel additives. In redox
reactions, high energy substances or electro-reductive
processes are needed because of high thermodynamic
stability and lower reactivity of CO2.12 Chemical
reduction routes are being explored for the reduction
processes. Very recently, a research group
from University of California at Los Angeles
reported a method wherein genetically engineered
microorganism was deployed for the successful
conversion of CO2 into fuels such as iso-butanol and
3-methyl-1-butanol.13 Carbon Sciences, a Californiabased company is developing a bio-catalytic
Fig. 3 − Overall scheme for the utilization of CO2 for the
production of fuel, fuel additives and bio-derived chemicals.
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INDIAN J CHEM, SEC A, SEPT-OCT 2012
Fig. 5 − Hydrogenation of CO2. [Adapted from Ref. 15 with
permission from Elsevier, Amsterdam, The Netherlands].
Carbon monoxide
Conversion of CO2 via reverse water gas shift
(RWGS) reaction is the most lucrative route for the
production of CO (Eq. 1) that can further be used in
Fischer-Tropsch (FT) process to produce hydrocarbons.
Fig. 4 − Schematic representation of fuel and fuel additives
production from CO2.
…(1)
process for converting CO2 into hydrocarbons such as
methane, ethane and propane, which can be utilized
instead of gasoline and jet fuels.14 Generally,
biocatalytic routes are more expensive and time
consuming than other catalytic routes. Highly active
metal catalysts have been investigated for the
hydrogenation of CO2 in homogenous or
heterogeneous forms.
Hydrogenation of CO2 results in various products
of C1-type and higher chain length hydrocarbons
depending upon the reaction conditions. Hydrogen is
generally obtained either from fossil sources or
through water splitting. Development of various
catalyst systems and surface science techniques has
created interest in the hydrogenation of CO2
in recent years. Direct hydrogenation of CO2
and hydrogenation of CO obtained from CO2 are
among the two possible ways for producing
fuels. Some of the previous studies15 have
suggested that CO2 hydrogenation proceeds via the
dissociative adsorption of CO2 to form CO and O
atoms on the surface, which on further
hydrogenation renders products as shown in Fig. 5.
Several routes can be proposed for the use of CO2 in
hydrogen reduction such as (i) conversion to
products via synthesis gas, (ii) direct hydrogenation
into useful products, and, (iii) reactions to other
products via MeOH.16
This section mainly covers the hydrogenation
process of CO2 for the production of fuels.
The equilibrium can be shifted towards the right by
(a) increasing the CO2 concentration, (b) operating at
high H2 concentration, and, (c) removing the product
(water) from the system.17 Different metals such as Cu,
Zn, Fe and Ce containing catalysts are well known for
the WGS reaction and these catalysts can effectively
carry out RWGS reaction also. Apart from these,
Pt catalyst was also studied for RWGS reaction with
different catalyst supports.18,19 Recently, Rosen et al.20
reported electroreduction of CO2 to CO below
overpotential using ionic liquid as electrolyte and
silver cathode as catalyst.
The formation of CO in RWGS reaction is
explained by two models, namely, redox mechanism
and formate decomposition mechanism. In the case of
redox mechanism it was suggested that reduction of
CO2 and oxidation of H2 that result in the formation of
CO and H2O, occur due to the metal species.21 In the
case of formate decomposition mechanism, it was
suggested that association of H2 with CO2 results in
formate species as intermediate which decomposes to
give CO.22
Even at 400 °C, due to the low equilibrium
constants, it requires hydrogen-rich or carbon dioxiderich reactant mixtures to yield acceptable results.
Otherwise the operating temperature needs to be
increased to around 750 °C. It was identified that
activity of the catalysts depends on the operating
temperature23 and both ZnO-Al and ZnO-Cr catalysts
show poor activity below 600 °C. Theoretical studies
SIVASHUNMUGAM & KANNAN: CO2 AS POTENTIAL RAW MATERIAL FOR FUEL PRODUCTION
to determine the likely reaction mechanisms
augmented by instrumental techniques, is the
requirement at this stage to design and develop
improved catalysts that can work under energy
efficient conditions.
Hydrocarbons
Fischer-Tropsch synthesis is a well-known reaction
wherein CO is hydrogenated to give hydrocarbons. In
a modified FT process, hydrocarbons can be prepared
by hydrogenating syngas (CO + H2) that contains a
considerable amount of CO2 or by hydrogenating CO2
via CO and CH3OH formation (Eqs 2 & 3). The main
criterion for this reaction is the additional
functionality of the catalyst which predominantly
forms hydrocarbons. Even though catalytic FT
process is well established, only a few studies are
reported for catalytic hydrogenation of CO2 for
hydrocarbons production. CO2 emission from
transportation fuels can be utilized with H2, which
may be obtained from solar power, etc. This is one of
the possible effective ways to maintain carbon cycle.
Processes such as photochemical, electrochemical and
thermochemical are applicable for the catalytic
conversion of CO2 of which the first two routes have
some drawbacks. Hence, thermochemical CO2
conversion is preferred for producing hydrocarbons
with high conversions.24
… (2)
…(3)
Transition metal catalysts have been reported for
catalytic hydrogenation of CO2 and/or syngas to
hydrocarbons. In some studies, FT process was
checked with the feeding of CO2 gas along with
syngas to produce the hydrocarbons. Fe based FT
catalysts are promising for hydrocarbons synthesis
and various efforts have been made to increase the
conversion of CO2.25 Dorner et al.26 reported the
hydrocarbons production using ceria modified iron
catalysts. They have reported that addition of ceria
enhances the CO2 conversion and selectivity for C2-C5
hydrocarbons. Cobalt-based catalysts have also been
studied for the FT process and were not found
attractive for the production of long chain length
hydrocarbons. Iron-based FT catalysts are reported
for high temperature processes whereas cobalt-based
FT catalysts are reported for low temperature
1255
processes.27 CO2 and CO follow different pathways
during hydrogenation that largely depend on the
nature of the catalyst. For example, Fe based catalysts
promote hydrocarbons production via CO formation
whereas Co based catalysts convert CO2 directly to
methane due to its limited WGS reactivity. In
addition, supports and promoters also play an
important role in CO2 hydrogenation. Although many
efforts are being made for the production of
hydrocarbon from CO2, specific methodologies/
technologies to improve the selectivity of the desired
products are required.
Methanol
Methanol (CH3OH) is an important chemical that
finds application in various industrial processes. It
was identified that worldwide consumption of
methanol increased by 1 % from 2003 to 2008 and is
projected to increase by 2 % from 2008 to 2013.28
Such robust growth obviously suggests high market
potential for methanol and efforts are continuously
being made to increase its production and meet global
demands. Methanol can be directly used as fuel or as
an additive to gasoline and can also be used as
platform chemical for the synthesis of various
chemicals. Currently, the focus is on methanol for the
production of biodiesel (fatty acid methyl esters) by
transesterification of vegetable oils. Generally,
methanol can be produced from CO2 /CO and hydrogen
(Eqs 4 & 5). Methanol Holdings (Trinidad) Limited
(MHTL), a USA based company, is one of the largest
methanol producers in the world with a total capacity
of over 4 MMT/year.29 It is well known that CO2 is the
preferred substrate for methanol production than CO
because it forms active carbonates/formates on catalyst
surface which favour the reaction. Also it was
evidenced that feeding small amount of CO2 facilitates
methanol production from syngas.
…(4)
…(5)
Methanol production by the hydrogenation of CO2
is possible using homogeneous as well as
heterogeneous catalysts. Generally, homogeneous
catalysts work at lower temperature for methanol
production than heterogeneous catalysts. Designing of
homogeneous catalysts to improve the reactivity and
selectivity is one of the main challenges being
pursued for the reaction.30 It was reported that
hydrogenation of CO2 occurs via RWGS reaction in
1256
INDIAN J CHEM, SEC A, SEPT-OCT 2012
which the water produced acts as an inhibitor for
further conversion into methanol. Hence, it is
necessary to design catalysts which show high activity
at lower temperature and can tolerate the water
formed during the reaction. Very recently, Leitner and
co-workers31 have reported the first molecularly
defined
ruthenium
phosphine
complex
as
homogeneous catalyst for efficient hydrogenation of
CO2 (turnover number > 200) to methanol under mild
reaction conditions. Cu based heterogeneous catalysts
are effectively studied for the methanol production
reactions.32,33 Precious metal supported catalysts are
also reported for this reaction.34
The function of the catalyst towards the selectivity
and water tolerance are not yet clearly understood.
Economically cheap catalyst which can overcome the
process drawbacks for the conversion of CO2 to
CH3OH is the necessity at this stage. Krossing and his
team35 from Freiburg Materials Research Center,
Germany, have developed a method for methanol
production using CO2 and H2. The obtained methanol
can be converted into gasoline through well-known
MTG process. Methanol production was carried out
under high pressure by combining CO2 and H2. Their
goal is to control CO2 emission in large scale along
with the complete utilization for energy production
and increasing the rate of chemical reaction by
designing new catalyst systems and methods. Metal
oxides were used to carry out the reaction at low
temperature and they found that nanoparticles
containing catalyst shows higher activity for methanol
production. They have also attempted different
preparation techniques such as catalyst impregnation
with ionic liquids and covering the catalyst with a thin
film of salt solutions that assist in fixing CO2 and H2
effectively on the catalyst and allow facile desorption
of products.35
One-step synthesis using bifunctional catalysts for the
synthesis of methanol as well as dehydration
of methanol to DME is plausible. Generally,
metal oxides are used for the production of methanol
and
acidic
catalysts
are
used
for
the
dehydration reactions.
...(7)
...(8)
...(9)
According to 2011 data37, Korea Gas Technology
Corporation, Korea, received a contract from Unitel
Technologies, Inc. to build a plant for the catalytic
production of DME at the scale of 300,000 tons per
year by single step method using tri-reformed syngas
obtained from natural gas as feedstock. They have
successfully demonstrated this one-step model unit
with 10 tons/day capacity.37
CO2 is thermodynamically more stable than H2O
and facilitates DME formation at higher temperature
with 1:1 feed of CO2/H2. Generally, a two-step
process is in practice because of the thermodynamic
favorability of methanol which gives DME via
dehydration reaction. Copper-based catalysts are
known for the selective production of methanol by
CO2 hydrogenation, which can be converted to DME
using acidic catalysts. Interestingly, Cu based core
shell membrane catalysts showed direct synthesis of
DME from CO2.38 Designing highly active
bifunctional catalysts which can produce DME from
CO2 under moderate reaction conditions, is the
targeted interest of this reaction.
Methane
Dimethyl ether (DME)
Dimethyl ether (CH3OCH3) is the first derivative of
methanol effectively used as an alternative for
LPGs.36 Traditionally, dehydration of methanol
results in DME in presence of acid catalysts (Eq. 6).
Care should be taken in the reaction conditions to get
DME from methanol because of the equilibrium
between the reactants and products.
...(6)
Hydrogenation of CO2 or syngas is an alternative
method for the production of DME (Eqs 7-9).
Methane has application as synthetic fuel and is
produced from the hydrogenation of CO2 by the
Sabatier reaction. The challenges associated in the
storage of hydrogen instrumental in the efforts to
convert it into methane that can be stored and
transported easily. Methane can be obtained by the
hydrogenation of CO or CO2; the latter process is less
exothermic than the former. Hydrogenation of CO or
CO2 (Eqs 10 & 11), commonly reported as
methanation, is also used in ammonia plants for the
purification of syngas, reducing the residual carbon
oxides in hydrogen-rich reforming gases and polymer
electrolyte fuel cell anodes.39
SIVASHUNMUGAM & KANNAN: CO2 AS POTENTIAL RAW MATERIAL FOR FUEL PRODUCTION
...(10)
...(11)
Selective methanation of CO in CO2-rich gas
mixtures has gained interest in recent years because of
its advantage as a viable alternate to selective CO
oxidation. In this case, CO adsorbs strongly on the
catalyst surface due to its higher adsorption energy
than CO2, resulting in surface blocking and thus
inhibiting CO2 adsorption, which in turn facilitates
methanation reaction.40 Easy availability and low cost
makes Ni based catalyst promising for industrial
methanation reactions. Overheating and sintering
results in problems such as decrease in the surface
area due to crystallite size growth of Ni and
deactivation of the catalyst. This may be overcome by
choosing proper supports that are mechanically and
thermally stable. Different metals such as Co, Ru and
Rh containing catalysts were also studied for the
methanation reactions.41-44 Particle size, operating
temperature and supports play a major role in the
methanation reaction. Developing a new technology
that selectively makes methane from CO/CO2 is of
considerable interest. Designing active catalyst and
developing a protocol to disperse the catalyst on a
rationally selected support and deriving optimized
reaction conditions for such systems are the hurdles
which have to be overcome. Methanogens (also called
as Archea) produce one billion ton of methane from
CO2 naturally every year. Hence, these microbes have
been suggested as one of the effective sources for the
preparation of methane and Europe has already
initiated this process.45
Dry reforming of methane with CO2 is the perfect
way to make syngas (ratio of H2/CO is 1) which is
one of the main building blocks for the fuels (Eq. 12).
The main advantage of dry reforming process is using
two greenhouse gases (CO2 & CH4) and this makes it
superior to steam reforming or partial oxidation of
methane. Fundamentally, dry reforming of methane is
an endothermic process and requires high temperature
(> 700 °C) to get moderate conversions.
...(12)
Methane dry reforming is a catalytic process and
development of a suitable catalyst that can sustain
under high temperature without deactivation and
produce high yields of syngas is the key endeavor for
1257
this reaction. Ni was effectively used due to its lower
cost and easier availability than noble metals such as
Rh, Ru, Ir, Pd and Pt containing catalysts which are
also active for this reaction. Formation of coke is the
main drawback as it involves deactivation of the
catalysts. The support is reported to plays a crucial
role in this reaction. Ni containing catalysts were
explored extensively with various supports and along
with promoters.46-49 Recently, Labrecque and Lavoie50
studied the activity of Fe catalyst in the presence of
electrical current and found that electron flow and
addition of water vapour play a crucial role in
methane conversion. Developing a technology that
improves the resistance toward carbon deposition and
designing the catalyst with proper support and/or
promoter which can enable this reaction at lower
temperature are the key challenges to be addressed in
the CO2 reforming of methane.
Ethanol
Ethanol (C2H5OH) is the one of the largest
producing alternative fuel from renewables by
fermentation process. Ethanol can be produced form
CO2/CO via hydrogenation process (Eqs 13 & 14).
Though direct hydrogenation of CO2 to C2H5OH is
possible, indirect method via methanol homologation
is in use only for the production of ethanol.
...(13)
...(14)
Hydrogenation of C2 oxygenates (such as
acetaldehyde and acetic acid from syngas which can
be made from CO2) to ethanol is the best possible
route. Catalysts with some active centres which can
reduce CO2 to CO, promoting C-C bond formation
and allowing –OH group insertion are the main
criteria for this reaction. Composite catalysts
satisfying the above mentioned properties were
studied for this reaction due to their multifunctional
nature.51,52 Potassium supported Cu based catalysts
have shown high activity for this reaction; herein,
potassium acts as a promoter for C-C bond forming
reaction.53 Rh based catalysts have also been studied
and it was found that promoters play a crucial role for
the selectivity of ethanol.54 Modification of catalysts
was attempted to satisfy the requirement of the
reaction condition; Rh containing catalysts showed
the best results. Basically, catalysts which are active
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INDIAN J CHEM, SEC A, SEPT-OCT 2012
for ethanol production from syngas and RWGS are
also active for methanol homologation reactions.
Ethanol has been undoubtedly proved to be the best
alternative for fuels and enzymatic production
predominates for its production. Designing the
catalyst with highly efficient production of ethanol
from CO2 is the challenging task in front of many
researchers. New technology developments are
required to replace and/or augment the currently
practiced microbial process.
Formic acid
Formic acid (HCOOH) is the simplest carboxylic
acid and its worldwide production was estimated to be
around 720,000 tonnes/annum in 2009.55 It has
application in various areas including fuel cells.
Commercially, formic acid is produced by four
different production processes, viz., methyl formate
hydrolysis, oxidation of hydrocarbons, hydrolysis of
formamide, and, preparation of free formic acid from
formates.
Direct hydrogenation of CO2 is the best alternative
method for production of formic acid (Eq. 15).
section discusses the non hydrogenation process of
CO2 (or CO) for the production dimethyl carbonate.
Dimethyl carbonate (DMC; (CH3O)2CO) is a linear
alkyl carbonate and has been reported as a potential
gasoline fuel additive.58 Various methods are possible
for the production of DMC from methanol. High
toxicity of phosgene gas and formation of
hydrochloric acid as by-product are the drawbacks of
the ongoing phosgene-based process. Alternative
routes are utilizing CO2 or CO as reactant for the
production of DMC from methanol. Lummus
Technology developed a process in which reaction
between methanol, carbon monoxide and oxygen in
presence of Cu-based catalysts results in DMC and
water (Eq. 16).59 A small amount of HCl is fed into
the reactor to maintain the catalyst activity and the
obtained byproduct CO2 can be further used for
CO production.
+
...(16)
...(15)
Mainly, homogeneous transition metal catalysts
and zinc selenide/zinc telluride have been studied for
this reaction.56 British Petroleum has developed a
multistep process using Ru complex as catalyst in
presence of nitrogen-containing bases.56 Even though
efforts have been made to produce formic acid using
homogeneous catalysts, recent reports suggest that
formic acid can be produced from CO2 hydrogenation
with high selectivity using heterogeneous catalysts.57
Development of new catalytic technology to produce
formic acid in attractive yields in a safe manner is the
major task.
CO2 for the Production of Fuel Additives
Efforts have been made to produce fuel additives
from CO2 without using hydrogen source. Generally,
this non-hydrogenation process results in carbonates
and carbamates; among these, carbonates were found
to be effective fuel additives. Dimethyl carbonates are
prepared by reacting methanol with CO2. Methanol,
which is produced by the hydrogenation of CO2,
undergoes dehydration when treated with CO2
resulting in dimethyl carbonates. Also, oxygenation of
CO which is produced by the RWGS of CO2, is
another way to produce dimethyl carbonate. This
Production of DMC using CO2 with methanol is a
preferred route (Eq. 17). It was found that
thermodynamic
limitation
of
the
reaction,
deactivation of the catalyst and hydrolysis of the
DMC by the formed water results in low methanol
conversion and low DMC yield. Selective synthesis of
DMC is highly influenced by the presence of both
acidic and basic sites on the catalyst surface.60
Reaction temperature is an important parameter for
DMC synthesis. At higher temperatures, conversion
of methanol and selectivity of DMC are decreased
due to decomposition of DMC and result in unwanted
products.61
+
...(17)
Various catalysts were reported for this reaction
and many diverse efforts were made to improve the
selective synthesis of DMC such as catalyst
modification, addition of co-reagents and dehydrating
agents.62-65 Improving the conversion of methanol
along with selectivity of DMC is necessary for it to be
SIVASHUNMUGAM & KANNAN: CO2 AS POTENTIAL RAW MATERIAL FOR FUEL PRODUCTION
1259
commercially practicable. Designing the desired
catalysts and developing a new or redeploying water
removal technology are the basic requirements
necessary to achieve this endeavour.
bio-reactors and for making bio-derived chemicals.69,70
The primary aim of this section is to highlight the role
of CO2 in the synthesis of biomass derived chemicals,
in particular organic carbonates (Fig. 6).
CO2 for the Production of Bio-derived Chemicals
Biomass mainly constitutes of lignocelluloses and
related materials (70-75 % of biomass), oils and fatty
acids (15-20 % of biomass) and proteins (5 % of
biomass). It is estimated that around the world
approximately 170 BMT of biomass are being
produced per annum.66 Of this barely 4 % is used for
food/feed and non-food purposes by the humans.67
Hence, biomass is perceptibly a potential alternate
source for the production of fuels and chemicals.
Using biomass for energy producing processes also
results in the emission of CO2, but the amount
produced during this process is approximately the
same as that consumed during biomass re-growth.
Hence, emission of CO2 from biomass is considered as
CO2 neutral.68 The combination of biomass and CO2 in
energy conversion technologies has some similarities
with the combination of fossil sources and CO2. CO2,
in the context of biomass value addition, is currently
being explored as a solvent for pre-treatment of
biomass for delignification, for the growth of algae in
Fatty cyclic carbonate
In recent years, fatty cyclic carbonates have gained
interest in the area of renewable sources since they
have been used in lubricants, fuel additives and
polymer precursors, as solvents, biomedical
applications and in plasticizers.71,72 Traditionally,
these kinds of cyclic carbonates were prepared by
using hazardous phosgene gas and organic solvents.
CO2 insertion reaction can play a profound role in the
synthesis of cyclic carbonates. Generally, two step
processes are carried out for the preparation of fatty
cyclic carbonates such as sequential epoxidation of
unsaturated centers and then carboxylation of the
epoxy fatty derivatives. The main advantage of this
process is insertion of CO2 without forming any
byproducts (100 % atom economical). Direct
oxidative carboxylation of fatty derivatives can also
result in fatty cyclic carbonates (Scheme 1).
Doll and Erhan73 have reported the production of
carbonated FAMEs using supercritical CO2. They
reported a two-step reaction for the production of
fatty cyclic carbonates from methyl oleate and methyl
linoleate. In the first step, the unsaturated centres
present in these methyl esters were converted into
epoxides and then CO2 was direct inserted in the
oxirane ring using tetrabutylammonium bromide as
catalyst under supercritical CO2. The same catalyst
was studied for the carbonation of epoxidized soybean
oil methyl esters at atmospheric pressure and at
pressurized conditions.74 Interestingly, Kenar and
Preparation of fatty cyclic carbonates from fatty derivatives
Fig. 6 − Preparation of organic carbonates using CO2.
Scheme 1
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INDIAN J CHEM, SEC A, SEPT-OCT 2012
Tevis75 reported preparation of fatty cyclic carbonates
using tetramethylammonium hydrogen carbonate as
catalyst at low temperatures and in shorter reaction
time by bubbling with CO2.
Due to the renewable nature, bio-derived products
have gained interest in recent years. Fatty cyclic
carbonates have wide applications and researchers
are attempting to produce them in economically
attractive and in large volumes to replace some of
the petro-derived polymeric derivatives. Further,
most of the studies involve two-step processes for
the production of cyclic carbonates via epoxides
formation and CO2 insertion. Unfortunately, direct
oxidative carboxylation to produce fatty cyclic
carbonates is scarcely studied. Appropriate design
of catalyst that offers macroporosity for
efficient diffusion (avoiding mass transport
limitation) of the long-chain molecules which can
give high yield of fatty cyclic carbonates under near
ambient or energetically favorable conditions is the
challenge at present. Further, production of
polycarbonates and polyether carbonates from fatty
derivatives/vegetable oils using CO2 needs a more
focused approach.
Preparation of glycerol carbonate from glycerol
Scheme 2
were made for the direct insertion of CO2 into glycerol
moiety to form glycerol carbonate using tin based
catalysts.78,79 Formation of water as byproduct
prevents further conversion of glycerol due to
solubility of glycerol in water and the reaction is
thermodynamically limited (Scheme 2). It was
further identified that addition of methanol can
enhance the reaction.79
Direct carboxylation of glycerol to glycerol
carbonate is an important reaction not only in being
industrially relevant but also in green chemistry
perspective. Technology development to increase the
conversion of glycerol concomitantly with high
selectivity of glycerol carbonate is indispensable at
this time.
Glycerol carbonate
Glycerol is the simplest triol which has various
applications due to its functionality. Glycerol can be
obtained from triglycerides via hydrolysis or
transesterification processes. The continuously
expanding production of biodiesel from different
sources results in enormous amounts of glycerol as
byproduct. In order to reduce the disposal of glycerol
as waste, value addition of glycerol for a variety of
applications is being studied. Glycerol carbonate is
important as solvent and starting material for
polymers etc., due to its peculiar properties.
Industrially this compound is produced by the
transesterification of propylene carbonate with
glycerol. Basically these carbonate derivatives are
prepared by the CO2 insertion reaction with the
corresponding oxides.
Earlier studies revealed that ethylene carbonate was
needed as starting material for the preparation of
glycerol carbonate from glycerol and supercritical
CO2 as carbonate source.76 In this case ethylene
carbonate can enhance the CO2 utilization for glycerol
carbonate synthesis. Very recently, Ma et al.77
reported the synthesis of glycerol carbonate from
glycerol and CO2 in presence of propylene oxide as
the coupling agent using alkali catalysts. Some efforts
Conclusions & Perspectives
The global atmospheric concentration of CO2 is
increasing every year and has reached 391.3 parts per
million in 2011 according to the data from
Worldwatch Institute.80 Increasing CO2 level in the
atmosphere can be controlled by utilizing it in a useful
and voluminous way, given its availability in giga
tons, through the production of fuels and large volume
chemicals. Decreasing fuel availability has created
enormous interest in the search for alternatives from
different sources and various attempts are being
explored. Syngas, methanol and hydrocarbons, are
some of the important options for the production of
fuels (or can be used as such) due to their properties.
Also, possibilities of forming various products from
CO2 would be of great significance since the endproducts obtained after combustion of fossil fuel can
be refurbished back into the fuel chain, thus closing
the energy/material loop cycle. Needless to say, the
energy penalty and balance are some of the key issues
that need to be sharply addressed while exploring
such options. Utilizing CO2 to develop large volume
chemicals, in particular those derived from biomass,
is one of the biggest opportunities in this area of
research. Although not many profitable technological
SIVASHUNMUGAM & KANNAN: CO2 AS POTENTIAL RAW MATERIAL FOR FUEL PRODUCTION
solutions are available at present, solutions that would
not only limit the growth of CO2 in atmosphere but
also create some sustainable options for the growing
population and energy/material demands of this world
are expected in this century.
Acknowledgement
The authors thank CSIR, New Delhi, India, for
financial support under Network Project, Clean Coal
Technology (NWP-021).
References
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
http://www.iea.org/co2highlights/co2highlights.pdf
(Accessed on 26th June 2012).
Song C, Gaffney A F & Fujimoto K F, CO2 Conversion and
Utilization, (ACS Symposium Series 809, American
Chemical Society, Oxford University Press, Washington,
D.C.) 2002, Chap. 1.
http://co2now.org/images/stories/graphics/carbon-budget/ 2010/
global-carbon-budget-2010-hi-rez.png
(Accessed
on
29th June 2012).
Marland G & Turhollow A F, Energy, 16 (1991) 1307.
http://205.254.135.7/forecasts/ieo/emissions.cfm (Accessed
on 25th June 2012).
Wang M, Wu M & Huo H, Environ Res Lett, 2 (2007) 1.
Zevenhoven R, Eloneva S & Teir S, Catal Today, 115
(2006) 73.
Leitner W, Coord Chem Rev, 153 (1996) 257.
Aresta M & Dibenedetto A, Dalton Trans, (2007) 2975.
Sakakura T, Choi J & Yasuda H, Chem Rev, 107 (2007) 2365.
Eggersdorfer M, Meijer J & Eckes P, FEMS Microbiol Rev,
103 (1992) 355.
Baiker A, Appl Organomet Chem, 14 (2000) 751.
http://www.extremetech.com/extreme/124383-bacteria-convertscarbon-dioxide-into-liquid-fuel (Accessed on 26th June 2012).
http://articles.cnn.com/2008-10-08/tech/co2.fuel_1_recycling
-projects-fuel-co2?_s=PM:TECH (Accessed on 26th June 2012).
Iizuka T, Tanaka Y& Tanabe K, J Catal, 76 (1982) 1.
Xiaoding X & Moulijn J A, Energy & Fuels, 10 (1996) 305.
Centi G & Perathoner S, Catal Today, 148 (2009) 191.
Kim S S, Lee H H & Hong S C, Appl Catal A: Gen, 423-424
(2012) 100.
Goguet A, Meunier F C, Tibiletti D, Breen J P & Burch R,
J Phys Chem B, 108 (2004) 20240.
Rosen B A, Salehi-Khojin A, Thorson M R, Zhu W, Whipple
D T, Kenis P J A & Masel R I, Science, 334 (2011) 643.
Fujita S I, Usui M & Takezawa N, J Catal, 134 (1992) 220.
Shido T & Iwasawa Y, J Catal, 140 (1993) 575.
http://www.marspedia.org/index.php?title=Reverse_WaterGas_Shift_Reaction (Accessed on 27th June 2012).
Dorner R W, Hardy D R, Williams F W & Willauer H D,
Appl Catal A: Gen, 373 (2010) 112.
Chun D H, Lee H, Yang J, Kim H, Yang J H, Park J C, Kim
B & Jung H, Catal Lett, 142 (2012) 452.
Dorner R W, Hardy D R, Williams F W & Willauer H D,
Catal Commun, 15 (2011) 88.
Gnanamani M K, Shafer W D, Sparks D E & Davis B H,
Catal Commun, 12 (2011) 936.
1261
28 Davenport R E, Issues Facing Global Methanol Industry, (SRI
Consulting. Presented to Chemical Week Conference) 2004.
29 http://www.energy.gov.tt/energy_industry.php?mid=47
(Accessed on 27th June 2012).
30 Huff C A & Sanford M S, J Am Chem Soc, 133 (2011)
18122.
31 Wesselbaum S, vom Stein T, Klankermayer J & Leitner W,
Angew Chem Int Ed, 51 (2012) 7499.
32 Zhang L, Zhang Y & Chen S, Appl Catal A: Gen, 415-416
(2012) 118.
33 Bonura G, Arena F, Mezzatesta G, Cannilla C, Spadaro L &
Frusteri F, Catal Today, 171 (2011) 251.
34 Kong H, Li H, Lin G & Zhang H, Catal Lett, 141 (2011) 886.
35 http://www.pr.uni-freiburg.de/pm/2012/pm.2012-06-13.137en/ (Accessed on 31st July 2012).
36 Arcoumanis C, Bae C, Crookes R & Kinoshita E, Fuel,
87 (2008) 1014.
37 http://www.businesswire.com/news/home/20110209005232/
en/Korea-Gas-Build-300000-Tons-Year-Dimethyl (Accessed
on 27th June 2012).
38 Zha F, Ding J, Chang Y, Ding J, Wang J & Ma J, Ind Eng
Chem Res, 51 (2012) 345.
39 Gabrovska M, Edreva-Kardjieva R, Crisan D, Tzvetkov P,
Shopska M & Shtereva I, React Kinet Mech Catal, 105
(2012) 79.
40 Eckle S, Augustin M, Anfang H & Behm R J, Catal
Today,181 (2012) 40.
41 Janlamool J, Praserthdam P & Jongsomjit B, J Nat Gas
Chem, 20 (2011) 558.
42 Sharma S, Hu Z, Zhang P, McFarland E W & Metiu H,
J Catal, 278 (2011) 297.
43 Sarusi I, Fodor K, Baan K, Oszko A, Potari G & Erdohelyi
A, Catal Today, 171 (2011) 132.
44 Beuls A, Swalus C, Jacquemin M, Heyen G, Karelovic A &
Ruiz P, Appl Catal B: Environ, 113-114 (2012) 2.
45 http://www.science20.com/news_releases/methanogen_
microbes_making_methane_from_co2_could_be_energys_ki
ller_app (Accessed on 27th June 2012).
46 Sokolov S, Kondratenko E V, Pohl M, Barkschat A &
Rodemerck U, Appl Catal B: Environ, 113-114 (2012) 19.
47 Du X, Zhang D, Shi L, Gao R & Zhang J, J Phys Chem C,
116 (2012) 10009.
48 Frontera P, Macario A, Aloise A, Crea F, Antonucci P L,
Nagy J B, Frusteri F & Giordano G, Catal Today, 179
(2012) 52.
49 Al-Fatesh A S A, Fakeeha A H & Abasaeed A E, Chinese J
Catal, 32 (2011) 1604.
50 Labrecque R & Lavoie J, Bioresour Technol, 102 (2011) 11244.
51 Inui T &Yamamoto T, Catal Today, 45 (1998) 209.
52 Inui T, Yamamoto T, Inoue M, Hara H, Takeguchi T &
Kim J B, Appl Catal A: Gen, 186 (1999) 395.
53 Arakawa H, Stud Surf Sci Catal, 114 (1998) 19.
54 Kusama H, Okabe K, Sayama K & Arakawa H, Catal Today,
28 (1996) 261.
55 http://en.wikipedia.org/wiki/Formic_acid
(Accessed
on
30th June 2012).
56 http://onlinelibrary.wiley.com/doi/10.1002/14356007.a12_
013. pub2/full (Accessed on 30th June 2012).
57 Zhang Z, Xie Y, Li W, Hu S, Song J, Jiang T & Han B,
Angew Chem Int Ed, 47 (2008) 1127.
58 Pacheco M A & Marshall C L, Energy Fuels, 11 (1997) 2.
1262
INDIAN J CHEM, SEC A, SEPT-OCT 2012
59 http://www.cbi.com/images/uploads/tech_sheets/DMC.pdf
(Accessed on 26th June 2012).
60 Tomishige K, Sakaihiro T, Ikeda Y & Fujimoto K, Catal
Lett, 58(1999) 225.
61 Aouissi A & Al-Deyab S S, J Nat Gas Chem, 21(2012) 189.
62 Lee H J, Park S, Song I K & Jung J C, Catal Lett, 141
(2011) 531.
63 Lee H J, Park S, Jung J C & Song I K, Korean J Chem Eng,
28 (2011) 1518.
64 Ballivet-Tkatchenko D, Bernard F, Demoisson F, Plasseraud
L & Sanapureddy S R, ChemSusChem, 4 (2011) 1316.
65 Zhang Z, Liu Z, Lu J & Liu Z, Ind Eng Chem Res, 50
(2011) 1981.
66 Corma A, Iborra S & Velty A, Chem Rev, 107 (2007)
2411.
67 Roper H, Starch/Starke, 54 (2002) 89.
68 Demirbas A, Prog Energy Combust Sci, 31 (2005) 171.
69 Zheng Y Z, Lin H M & Tsao G T, Biotechnol Prog,
14 (1998) 890.
70 Putt R, Singh M, Chinnasamy S & Das K C, Bioresour
Technol, 102 (2011) 3240.
71 Kenar J A, Knothe G, Dunn R O, Ryan T W I & Matheaus A,
J Am Oil Chem Soc, 82 (2005) 201.
72 Tamami B, Sohn S, Wilkes G L & Tamami B, J Appl Polym
Sci, 92 (2004) 883.
73 Doll K M & Erhan S Z, J Agric Food Chem, 53 (2005) 9608.
74 Holser R A, J Oleo Sci, 56 (2007) 629.
75 Kenar J A & Tevis I D, Eur J Lipid Sci Technol, 107 (2005) 135.
76 Vieville C, Yoo J W, Pelet S & Mouloungui Z, Catal Lett,
56 (1998) 245.
77 Ma J, Song J, Liu H, Liu J, Zhang Z, Jiang T, Fan H & Han B,
Green Chem,14 (2012) 1743.
78 Aresta M, Dibenedetto A, Nocito F & Pastore C, J Mol Catal
A: Chem, 257 (2006) 149.
79 George J, Patel Y, Pillai S M & Munshi P, J Mol Catal A:
Chem, 304 (2009) 1.
80 http://www.worldwatch.org/economic-recovery-brings-return
-growth-co2-emissions-0 (Accessed on 18th June 2012).