01505nas a2200265   4500008004100000022001400041245013700055210006900192260007300261300001400334490000600348520052600354653001600880653002300896653002100919653001500940653003500955653000800990100002200998700001901020700001901039700002401058700002901082856012801111       2008                        eng d  a1566-736700aPhosphotungstic acid on silica with modified acid sites as a solid catalyst for selective cleavage of tert-butyldimethylsilyl ethers0 aPhosphotungstic acid on silica with modified acid sites as a sol  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY  a1863-18680 v93 a<p>The strength and nature of acid sites of bulk phosphotungstic acid could be modified after dispersing it on silica support which was characterized by XRD, ammonia TPD and (31)P MAS NMR techniques. This solid acid catalyst was found to be highly selective for the cleavage of tert-butyldimethylsilyl ethers at room temperature. The catalyst was easily recovered by filtration and could be reused for several times without loss of any activity giving a TON of 9.5 x 10(5). (C) 2008 Elsevier B.V. All rights reserved.</p>10aAmmonia TPD10aCatalytic cleavage10areaction pathway10asolid acid10atert-butyldimethylsilyl ethers10aXRD1 aBhure, Mahesh, H.1 aKumar, Indresh1 aNatu, Arun, D.1 aChikate, Rajeev, C.1 aRode, Chandrashekhar, V.  uhttps://library.ncl.res.in/content/phosphotungstic-acid-silica-modified-acid-sites-solid-catalyst-selective-cleavage-tert-002240nas a2200229   4500008004100000022001400041245014100055210006900196260000800265300001400273490000800287520141800295653001801713653001601731653002701747653001601774653001501790100002201805700002301827700002901850856013101879       2024                        eng d  a1011-372X00aNovel sulfonic acid functionalized silica supported isonicotinic acid catalyst for conversion of 2-methylfuran to diesel fuel precursors0 aNovel sulfonic acid functionalized silica supported isonicotinic  cAPR  a1511-15200 v1543 a<p>Polyfuranic compounds produced after carbon up-gradation of 2-methylfuran by acid catalyzed C-C bond forming reactions when undergo hydro-deoxygenation produce diesel fuel. Herein, we prepared a simple and novel silica supported sulfonic acid functionalized isonicotinic acid SO3H-INA@SiO2 catalyst by treating isonicotinic acid with chlorosulphonic acid followed by heterogenization on silica. This heterogeneous solid acid catalyst was explored for the solvent free conversion of 2-methylfuran to diesel fuel precursors of C-15 and C-20 units via tandem ring opening followed by condensation sequence. Under optimized reaction conditions, SO3H-INA@SiO2 was able to convert, 2-methylfuran completely into condensation products such as 5,5-bis(5-methylfuran-2-yl)pentan-2-one (1) and 2,4,4-tris(5-methylfuran-2-yl)pentan-1-ol (2) with 19% and 67% yields, respectively. The heterogeneous SO3H-INA@SiO2 catalyst was successfully recycled up to six consecutive runs without loss of its activity. The SO3H-INA@SiO2 catalyst offered superior activity as compared to the commercially available -SO3H functionalized resins. Superior activity of the prepared catalyst could be attributed for its higher acidity, smaller particle size and high surface area. Structure of the prepared catalyst was confirmed by FTIR and solid state NMR. Total acidity of the prepared catalyst was determined by acid-base titration.</p>
10a2-Methylfuran10aDiesel fuel10aheterogeneous catalyst10aIonic solid10asolid acid1 aTarade, Komal, P.1 aKamble, Sanjay, P.1 aRode, Chandrashekhar, V.  uhttps://library.ncl.res.in/content/novel-sulfonic-acid-functionalized-silica-supported-isonicotinic-acid-catalyst-conversion-2