SusChemE 2015
International Conference on Sustainable Chemistry & Engineering
October 8-9, 2015, Hotel Lalit, Mumbai
Application of ionic liquids as catalysts in the synthesis of HMF from
chitosan
Dr Sunil S. Joshi1, Dr Kiran V. Pandare2, Priyanka Bhongale1, Sagar Chaudhary1 and
Anubhuti Bhatnagar1
1 Chemical Engineering and Process Development Division, NCL, Pashan, Pune
2 Polymer Science and Engineering Division, NCL, Pashan, Pune
Email Addresses: ss.joshi@ncl.res.in, kv.pandare@ncl.res.in, pv.bhongale@ncl.res.in,
sd.chaudhary@ncl.res.in, bhatnagar.anubhuti@gmail.com
1. Introduction
The increasing cost and environmental considerations are driving efforts to develop
alternative and sustainable ways to meet the energy and raw material needs of the
growing world. Such a shift away from petroleum based technologies is primarily
attempted by using lingo-cellulosic biomass. Hydrolysis of highly functionalized
lignocellulosic biomass suffers from disadvantages of variable composition and seasonal
availability [1] (Bozell 2004). Chitosan, on the other hand, is one of the most abundant
biopolymer in nature and is obtained by deacetylation of chitin using alkali. Source for
chitin are the shells of crustacean organisms, whose availability throughout the season
and near constancy in composition of shell make chitosan a sustainable resource. Various
platform chemicals like levulinic acid, 5- hydroxymethyl furfural (HMF), furfural,
acetamidofuran, glucosamine and other low molecular weight chito-oligomers can be
synthesised from chitosan [2] (Harish Prashanth & Tharanathan 2007).
Material and Method:
HMF is a key for synthesis of various compounds with applications in fuel, polymer,
textiles, and flavouring industries [3] (Teong et al. 2014). In the present research work,
conventional methodology of using aqueous mineral acids for the hydrolysis of chitosan
for synthesis of HMF has been modified to evolve a greener process. Myriad of catalysts,
including heterogeneous and homogeneous catalysts, were designed and hydrolysis of
chitosan was performed under hydrothermal condition. Catalysts were selected on the
basis of literature survey for similar biochemical conversions. These included various
modified zirconia based systems, zeolites, supported acid catalysts and ionic liquids (ILs)
with different anion and cation combinations. Water was used as the solvent in all the
cases because it makes the synthesis economical and environment friendly. Amongst all
the systems studied, ionic liquids used as catalysts showed high thermal stability,
negligible vapour pressure and chitosan was found to have good solubility in water in
their presence. Ionic liquids have been sought after in green catalytic technologies
because their properties can be tuned according to the requirements by altering the
1
combinations of cations and anions. Their application in biomass conversion has led to
development of several processes such as hydrolysis, alcoholysis and hydrogenation for
conversion of sugars.
3. Significant Results and Discussion:
IR and NMR studies performed for catalyst characterization revealed the nature and
structure of the IL and it was found to have a selectivity of 25% towards the product.
Once the most suitable ionic liquid was defined for the process; a detailed parameter
optimization helped in analyzing the sensitivity of the reaction towards duration,
temperature and catalyst loading.
30
100
25
80
20
(%)
60
15
40
10
Conversion(%)
Synthesis of HMF from Chitosan
20
5
0
0
IL4
ZnCl2
H beta
IL1
Catalyst
Selectivity of HMF(%)
Yield of HMF (%)
IL1/ silica
gel
Conversion of CHT(%)
Figure 1: Synthesis of HMF from Chitosan using different catalysts
2 g of chitosan, 2 wt % of catalyst in 100 mL of deionized water; reaction temperature 180 °C and reaction
time 180 minutes.
Parameter
HMF
Time
Temperature
Catalyst
Catalyst: Chitosan
Conversion (%)
Selectivity (%)
Yield (%)
120 min
1800C
Ionic liquid 1
1:1
78
25
19
Figure 2: Best reaction conditions for desired products obtained after parameter
optimization
2
4. Conclusions:
It was brought out through this work that chitosan undergoes acid hydrolysis during
synthesis of HMF. The environmental impact of acid hydrolysis of chitosan was assessed
for the synthesis of HMF. E factor was found to be 6.4 while the atom efficiency was
70%. Thus it is emphasized that there is a scope of improvement in the process to make it
more competent by process intensification.
References:
[ 1] Bozell, J.J., RENEWABLE FEEDSTOCKS FOR THE PRODUCTION OF CHEMICALS
[ 2] Harish Prashanth, K.V. & Tharanathan, R.N., Trends in Food Science & Technology,
18(3), 2007. pp.117–131.
[ 3] Teong, S.P., Yi, G. & Zhang, Y., Green Chemistry, 16(4), 2014. pp.2015–2026.
3