Claisen‐Schmidt condensation have historical significance for over140 years and the scope was expanded due to the realization that chalcones so synthesized possess biological activity. The principles of green chemistry with emphasis on use of different solid catalysts with proper distribution of active centers such as acid, base, acid‐base, organo‐ were used along with solvent‐less systems. Among solid bases layered double hydroxides (LDH)/hydrotalcites are the most common. The limitations of solid bases are overcome by solid acids and superacids. A number of metal oxide supports are used. MOFs are increasingly being used. Complex organo‐catalysts are employed for getting excellent regio‐selectivity. In certain metal oxides, both acidic and basic sites co‐exist on the pore surface of catalyst which offer superior results. Synergism of solid catalysis using microwaves and ultrasound to intensify rates and selectivity is in vogue.Controlled pore structure and distribution of active catalytic centers, whether mono‐, bi‐ or tri‐functional catalysts, will give better green and smart processes. The review gives a critical analysis of the area and presents future directions for research.
Increasing demand for transportation
fuels, awareness of climate
change, and dwindling supplies of crude oil has led to the rapid increase
in production of biomass derived oxygenated fuel additives as viable
drop-in fuels for potential blending with conventional fuels. The
biorefinery processes for synthesis of oxygenated fuel additives using
metal oxide catalysts in various forms have evolved significantly.
Metal oxides exhibit diverse structures and physiochemical properties
including acidity, basicity, and redox nature along with the lattice
oxygen vacancies, which by careful design and modification can be
tuned to optimize high catalytic activity and selectivity in several
organic transformations. Metal oxide based catalysts can be designed
for use in industries, as individual metal oxides or mixed metal oxides,
decorated with noble and non-noble metal nanoparticles, porous metal
oxides, and sulfonated metal oxides. In this review, we have attempted
to consolidate the progress made with catalytic applications of metal
oxides in the synthesis and production of oxygenated fuel additives
through several important biorefinery processes.
Selective or partial oxidation of organic compounds is one of the most important chemical processes due to its industrial significance and these intermediates formed in these reactions are used to...
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