293
initially selected candidates, a list of 30 interesting chemicals was obtained through
an iterative process. The list was further reduced to 12 building blocks considering
potential markets, complexity of synthetic pathway, functionality of molecule and
abundance. Of these 12 platform molecules, some are obtained through biochemical
methods and some others via thermochemical pathway. 1,4-Diacids (succinic,
fumaric and malic), 3-hydroxypropionic acid, aspartic acid, glutamic acid and itaconic acid were obtained from biochemical pathway. Xylitol, 2,5-furandicarboxylic
acid, levulinic acid, glucaric acid, sorbitol and 3-hydroxybutyrolactone were
reported through thermochemical pathway.
From the last decade, our research group is associated with biomass conversion,
working on heterogeneous catalytic approaches for the conversion and value addition of the above-mentioned platform molecules including the preparation of xylitol, sorbitol, succinic acid, 5-hydroxymethylfurfural (HMF) and
2,5-furandicarboxylic acid (FDCA). We have also focused on the valorization of
levulinic acid into various value-added products by finding efficient catalysts and
synthetic protocols. In this chapter, we have covered a brief outline of levulinic acid
synthesis, state of the art on catalytic interventions for preparation of levulinic acidbased products such as γ-valerolactone, arylated-γ-lactones and 4,4-diaryl-substituted pentanoic acid/esters. A summarized report on HMF preparation and its
selective conversion into FDCA using ruthenium-based catalysts has also been discussed here. The end of the chapter discusses the challenges of the mentioned
conversions.
2 Levulinic Acid
Levulinic acid (LA), a keto carboxylic acid from biomass, is an important building
block for fuels and chemicals harnessed by catalytic transformations. LA (C 5 H 8 O 3 )
is a white crystalline solid (<30 °C), soluble in aqueous and in common organic
solvents including polar solvents. LA is a potential intermediate for making alkyl/
aryl-substituted cyclic lactones, aliphatic alcohols including diols, cyclic/acyclic
amides, ketals, esters, acid halides, diketones, amino/halo-substituted keto carboxylic acids, alkane/alkenes, valeric acid/esters, cyclic ethers, etc.
2.1 Preparation of Levulinic Acid
LA is mainly prepared from cellulose-derived glucose by involving two steps. In the
first step of the reaction, glucose isomerizes to fructose and is subsequently dehydrated to HMF. In the second step, HMF under hydrolysis in aqueous medium forms
LA along with formic acid as a by-product (Scheme 1) [6]. The conversion in the
presence of alcoholic medium forms alkyl levulinates and alkyl formates [7]. Many
reports reveal the direct conversion of lignocellulose biomass (wheat straw, pulp
Levulinic Acid- and Furan-Based Multifunctional Materials: Opportunities…
initially selected candidates, a list of 30 interesting chemicals was obtained through
an iterative process. The list was further reduced to 12 building blocks considering
potential markets, complexity of synthetic pathway, functionality of molecule and
abundance. Of these 12 platform molecules, some are obtained through biochemical
methods and some others via thermochemical pathway. 1,4-Diacids (succinic,
fumaric and malic), 3-hydroxypropionic acid, aspartic acid, glutamic acid and itaconic acid were obtained from biochemical pathway. Xylitol, 2,5-furandicarboxylic
acid, levulinic acid, glucaric acid, sorbitol and 3-hydroxybutyrolactone were
reported through thermochemical pathway.
From the last decade, our research group is associated with biomass conversion,
working on heterogeneous catalytic approaches for the conversion and value addition of the above-mentioned platform molecules including the preparation of xylitol, sorbitol, succinic acid, 5-hydroxymethylfurfural (HMF) and
2,5-furandicarboxylic acid (FDCA). We have also focused on the valorization of
levulinic acid into various value-added products by finding efficient catalysts and
synthetic protocols. In this chapter, we have covered a brief outline of levulinic acid
synthesis, state of the art on catalytic interventions for preparation of levulinic acidbased products such as γ-valerolactone, arylated-γ-lactones and 4,4-diaryl-substituted pentanoic acid/esters. A summarized report on HMF preparation and its
selective conversion into FDCA using ruthenium-based catalysts has also been discussed here. The end of the chapter discusses the challenges of the mentioned
conversions.
2 Levulinic Acid
Levulinic acid (LA), a keto carboxylic acid from biomass, is an important building
block for fuels and chemicals harnessed by catalytic transformations. LA (C 5 H 8 O 3 )
is a white crystalline solid (<30 °C), soluble in aqueous and in common organic
solvents including polar solvents. LA is a potential intermediate for making alkyl/
aryl-substituted cyclic lactones, aliphatic alcohols including diols, cyclic/acyclic
amides, ketals, esters, acid halides, diketones, amino/halo-substituted keto carboxylic acids, alkane/alkenes, valeric acid/esters, cyclic ethers, etc.
2.1 Preparation of Levulinic Acid
LA is mainly prepared from cellulose-derived glucose by involving two steps. In the
first step of the reaction, glucose isomerizes to fructose and is subsequently dehydrated to HMF. In the second step, HMF under hydrolysis in aqueous medium forms
LA along with formic acid as a by-product (Scheme 1) [6]. The conversion in the
presence of alcoholic medium forms alkyl levulinates and alkyl formates [7]. Many
reports reveal the direct conversion of lignocellulose biomass (wheat straw, pulp
Levulinic Acid- and Furan-Based Multifunctional Materials: Opportunities…