(628f) Catalytic Defunctionalization of Biomass Derived Platform Molecules to Fuels and Chemicals

Catalytic
Defunctionalization of Biomass Derived Platform Molecules to Fuels and Chemicals

Md. Imteyaz Alam*^a,b, Shelaka Gupta^a, Basudeb Saha^b and
M. Ali Haider*^a

^a Laboratory of Catalysis,
Department of Chemistry, University of Delhi, North Campus,

Delhi-110007,
India

^b I-112, Renewable Energy and
Chemicals Laboratory, Department of Chemical Engineering, Indian Institute of
Technology, Delhi-110016, India

* Corresponding
author: Tel: +(91)-011-2766-6646, M:- 9289445506

E-mail: imteyaz84@gmail.com ; haider.iitd@gmail.com

Abstract

Sugar molecules obtained from a
variety of carbohydrate rich species of plants were utilized to develop a catalytic
process for efficient production of 5-hydroxymethyl furfural (HMF) using metal
salts¹,
ionic liquids (ILs)²
and titanium hydrogen phosphate (TiP)³. Metal salts such as ZrOCl₂/CrCl₃ in
combination with the IL (butyl methyl imidazolium chloride) acted as a
multifunctional catalyst for the conversion of lignocellulosic biomass via a
series of catalytic transformations which include hydrolysis, isomerization and
dehydration reactions to yield up to 57% HMF from cellulose as shown in Figure
1a. In order to achieve high acidity, sulfonic acid
functionalized ILs ([DMA]⁺[CH₃SO₃]^- and [NMP]⁺[CH₃SO₃]^-) were synthesized,
which were experimented to convert a variety of raw biomass, yielding 11
to 58% HMF. The best IL catalyst in terms of HMF
yield was used further to produce biofuels (ethoxymethyl furfural and ethyl
levulinate) directly from raw biomass. The maximum isolated yield of the pure
products was 0.28g/g of the raw biomass. It has been suggested in the literature
that glucose isomerization can be effectively done by a Lewis acid yielding fructose,
which is dehydrated to produce HMF. A combination of both Lewis and Brønsted acidity is desirable for an optimum design
of the catalyst for HMF synthesis. Therefore, a novel dual
acidic (Brønsted and Lewis) TiP catalyst was synthesized to achieve higher HMF yield. Indeed,
the catalyst produced 54% HMF (Figure 1b) with an added advantage of improved catalyst
stability and recyclability³. Density functional theory
(DFT) calculations estimated an intrinsic activation barrier of about 93.87
kJ/mole for the Lewis catalysed isomerization step on TiP and an overall
barrier of 160.13 kJ/mole for the Brønsted
catalyzed dehydration step. HMF on subsequent rehydration and hydrogenation
produces ϒ- valerolactone (GVL), which has been suggested as a
potential platform molecule. Mechanism of the ring?opening and decarboxylation
of GVL was studied using a DFT calculations⁴.
The ring-opening was suggested to proceed via the formation of a stable
oxocarbenium ion intermediate in water which plays an important role in
determining it?s reactivity⁴.
DFT calculations estimated an overall barrier of 81 kJ/mol for ring-opening
which was observed to be comparable to the experimental value (85 kJ/mol)
reported by Dumesic and co-workers. In a separate route an integrated
fermentation and catalytic process is being developed for effective conversion
of biomass to fuels and chemicals. The integrated process was compared to the
chemo-catalytic process involving HMF and GVL intermediates, and was observed
to be a relatively direct two-step conversion route. 

 

Figure 1. Results of (a) metal
salts catalyzed cellulose conversion (b) TiP catalyzed HMF production (c) DFT
calculated activation barrier for the ring-opening of GVL in water compared to
the experiments

REFERENCES

(1)      Dutta, S.; De, S.; Alam, M. I.; Abu-Omar, M. M.; Saha, B. Direct
Conversion of Cellulose and Lignocellulosic Biomass into Chemicals and Biofuel
with Metal Chloride Catalysts. J. Catal. 2012, 288, 8?15.

(2)      Alam, M. I.; De, S.; Dutta, S.; Saha, B. Solid-Acid and
Ionic-Liquid Catalyzed One-Pot Transformation of Biorenewable Substrates into a
Platform Chemical and a Promising Biofuel. RSC Adv. 2012, 2
(17), 6890.

(3)      Alam, M. I.; De, S.; Singh, B.; Saha, B.; Abu-Omar, M. M.
Titanium Hydrogenphosphate: An Efficient Dual Acidic Catalyst for
5-Hydroxymethylfurfural (HMF) Production. "Applied Catal. A, Gen. 2014,
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(4)      Gupta, S.; Arora, R.; Sinha, N.; Alam, M. I.; Haider, M. A.
Mechanistic Insights into the Ring-Opening of Biomass Derived Lactones. RSC
Adv. 2016, 6, 12932?12946.