01831nas a2200265   4500008004100000022001400041245013700055210006900192260000800261300001400269490000600283520090800289653001901197653001701216653002001233653002601253100002301279700002301302700002401325700002601349700002301375700002101398700002301419856012301442       2020                        eng d  a2193-580700aNew TBAF complex, highly stable, facile and selective source for nucleophilic fluorination: applications in batch and flow chemistry0 aNew TBAF complex highly stable facile and selective source for n  cJUL  a1022-10260 v93 a<p>Natural polysaccharides supported tetrabutylammonium fluoride (TBAF) complexes are prepared and found to be highly stable and selective fluoride source for well-renowned nucleophilic (SN2 type) fluorination reactions for the first time. Bacterial cellulose, plant cellulose, pectin, and starch derived TBAF complexes are synthesized, characterized (using SEM, TEM, and NMR techniques) and studied for their stability and reactivity. Heterogeneous bacterial cellulose-TBAF complex (NBu4(Bac-cell-OH)F) 1 was found to be highly stable and non-hygroscopic among all complexes, which gave high yields of fluorinated products in multi-gram scale in shorter reaction time. The primarily developed batch protocol was extended to solid-solid continuous flow reaction using an in-house built screw reactor, which furnished products in a few seconds of residence time (tR=20-25 sec) and excellent yields.</p>
10aFlow synthesis10afluorination10agreen chemistry10aSustainable Chemistry1 aSaid, Madhukar, S.1 aKhonde, Nilesh, S.1 aThorat, Meghana, N.1 aAtapalkar, Ranjit, S.1 aKulkarni, Amol, A.1 aGajbhiye, Jayant1 aDastager, Syed, G.  uhttp://library.ncl.res.in/content/new-tbaf-complex-highly-stable-facile-and-selective-source-nucleophilic-fluorination02307nas a2200181   4500008004100000022001400041245009000055210006900145260000900214300001600223490000700239520167700246100002701923700001701950700001601967700002301983856011902006       2020                        eng d  a0888-588500aNovel flow reactor for handling suspensions: hydrodynamics and performance evaluation0 aNovel flow reactor for handling suspensions hydrodynamics and pe  cSEP   a16462-164720 v593 a<p>A novel reactor concept that can handle solid particles without any moving components in the reactor is proposed and demonstrated in this work. The proposed reactor is designed by arranging the unique shape cavities in a sequence where inlet and outlets are positioned off-center to each other at specific angles and distance. Detailed flow simulation suggested that cavities with diameter D, having aspect ratio H/D similar to 1.53, outlet (having a diameter of 0.2D) positioned at 0.3D from the center and at 180 degrees with reference to the inlet is suitable for the expected performance. The proposed geometry of the reactor with the optimal geometrical configuration was fabricated and hydrodynamics (viz. pressure drop, mass transfer, and heat transfer, and residence time distribution) were studied. The reactor also offered high mass transfer coefficients and is useful for liquid-liquid reactions and extraction. A variety of solid suspensions (glass particles, activated carbon, starch particles, magnesium hydroxide) were tested over a wide range of flow rates for checking the solid handling capability of the reactor. The neutralization reaction of NaOH (with dissolved a-naphthol) with concentrated HCl that results in almost instantaneous precipitation of a-naphthol from the solution is used as a test reaction for a range of a-naphthol concentrations to change the suspension loading. It is shown that the proposed reactor can handle up to 22% (w/v) solid concentration without any clogging for a longer duration of the operation. However, for sticky solid particles, the same reactor would get clogged at the outlet ports for smaller diameters.</p>
1 aSharma, Mrityunjay, K.1 aSuru, Aditya1 aJoshi, Anuj1 aKulkarni, Amol, A.  uhttp://library.ncl.res.in/content/novel-flow-reactor-handling-suspensions-hydrodynamics-and-performance-evaluation