@article { ISI:000290787100020, title = {Regioselective monoalkylation of dimethyl alkylidenesuccinates: simple approach to dialkyl-substituted maleic anhydrides including chaetomellic acid A}, journal = {Synthesis-Stuttgart}, number = {11}, year = {2011}, month = {JUN}, pages = {1804-1808}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Natural and nonnatural dialkylmaleic anhydrides were readily prepared from dimethyl alkylidenesuccinates by sodium hexamethyldisilazide-induced selective monoalkylation followed by base-catalyzed hydrolysis.

}, keywords = {alkylations, Esters, furans, heterocycles, maleic anhydrides}, issn = {0039-7881}, doi = {10.1055/s-0030-1260013}, author = {Kshirsagar, Umesh A. and N. P. Argade} } @article { ISI:000334895800008, title = {Value addition to lignocellulosics and biomass-derived sugars: an insight into solid acid-based catalytic methods}, journal = {Journal of Chemical Sciences}, volume = {126}, number = {2, SI}, year = {2014}, note = {21st National Symposium on Catalysis (CATSYMP), CSIR Indian Inst Chem Technol, Hyderabad, INDIA, FEB 11-13, 2013}, month = {MAR}, pages = {373-385}, publisher = {Catalysis Soc India}, type = {Article, Proceedings Paper}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

For the synthesis of important platform chemicals such as sugars (xylose and arabinose) and furans (furfural and 5-hydroxymethylfurfural (HMF)) from carbohydrates (hemicellulose and fructose) solid acid catalysts are employed. Similarly, over solid acid catalysts, conversion of lignin into aromatic monomers is performed. It is observed that in the dehydration of fructose, because of higher hydrothermal stability, silicoaluminophosphate (SAPO) catalysts give better activity (78\% HMF yield) compared with other solid acid catalysts (\<63\% HMF yield) at 175 degrees C. Particularly, SAPO-44 catalyst can be reused at least 5 times with marginal decrease in the activity. Zeolite, BUSY (Si/Al = 15) is active in the conversion of isolated (pure) hemicellulose to produce 41\% C-5 sugars in water. The catalyst is also active in the selective conversion of hemicellulose from bagasse to yield 59\% C-5 sugars. It is possible to obtain high yields of furfural (54\%) directly from bagasse if instead of water, Water+toluene solvent system is used. Depolymerization of lignin using HUSY catalyst produced aromatic monomers with 60\% yield at 250 degrees C. A detailed catalyst characterization study is performed to understand the correlation between catalyst activity and morphology. To understand the effect of impurities present in the substrate over solid acid catalysts, metal-exchange study is carried out.

}, keywords = {aromatic monomers, Biomass, furans, Hemicellulose, lignin, solid acid catalyst}, issn = {0974-3626}, author = {Bhaumik, Prasenjit and Deepa, Ayillath K. and Kane, Tanushree and Dhepe, Paresh Laxmikant} } @article { ISI:000370664300002, title = {Solid acid catalyzed synthesis of furans from carbohydrates}, journal = {Catalysis Reviews-Science and Engineering}, volume = {58}, number = {1}, year = {2016}, month = {JAN}, pages = {36-112}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article}, address = {530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA}, abstract = {

The alternative feedstock, biomass (particularly lignocelluloses), having the profuse availability, is promising for the synthesis of several value-added chemicals which are currently obtained from fossil feedstock. In this article, the synthesis of two extremely significant furan chemicals viz. furfural and 5-hydroxymethylfurfural (HMF) are discussed. In the synthesis of furans from biomass, numerous challenges, i.e., use of edible sugars as substrates, selectivity to furans, their isolation in pure form, reuse of catalyst, environmental issues, etc., are perceived and in the recent past researchers tried to resolve those by developing advance methodologies. This article comprehensively summarizes the latest progress made in the above-mentioned areas and also provides commentary on the analyses of results, rationale for observed activity and mechanisms, etc. It also discusses future aspects of this work.

}, keywords = {Biomass conversion, carbohydrates, cellulose, furans, furfural, hemicelluloses, HMF, solid acid catalyst}, issn = {0161-4940}, doi = {10.1080/01614940.2015.1099894}, author = {Bhaumik, Prasenjit and Dhepe, Paresh Laxmikant} }