02254nas a2200229 4500008004100000022001400041245011800055210006900173260010600242300001200348490000800360520138400368653001101752653002201763653001201785653000901797653001601806653003001822100002301852700002201875856012701897 2013 eng d a0009-250900aDirect contact heat transfer via injecting volatile liquid in a hot liquid pool: generation and motion of bubbles0 aDirect contact heat transfer via injecting volatile liquid in a  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcAUG a421-4320 v1003 a

Direct contact heat transfer via injection of volatile liquid is an effective strategy for removing heat from a viscous liquid pool. The rapid evaporation effectively removes heat and the generated bubbles move quickly to the top surface. In this paper, we present an experimental and phenomenological analysis of the evaporation of a drop in a slightly miscible liquid. The phenomenon was visualized using a two-dimensional transparent experimental set-up with a single inlet at the bottom. The videos were used to estimate bubble dimensions, its rise velocity, distance from the detachment point, and fraction of vapor and the liquid phases in the evaporating drop. The initial drop size, temperature difference between the hot fluid and the low boiling solvent and the nucleation rate governed the rate of change of the drobble (combined entity of drop and bubble) diameter and its rise velocity. A phenomenological model describing transient behavior of drobble (motion and heat transfer) is developed. The transient variation in the interfacial areas for heat transfer and the projected area were found to have effect on the predictions. The model and results will also provide useful basis for extending the work towards better understanding of direct contact heat transfer in viscous systems like polymerization reactors. (C) 2013 Elsevier Ltd. All rights reserved.

10aBubble10aDirect contact HT10aDrobble10aDrop10aEvaporation10aSlightly miscible liquids1 aKulkarni, Amol, A.1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/direct-contact-heat-transfer-injecting-volatile-liquid-hot-liquid-pool-generation-and-001761nas a2200253 4500008004100000022001400041245006500055210006400120260007900184300001200263490000600275520092900281653001701210653003001227653001701257653001401274653001401288100001901302700002001321700002201341700002201363700002301385856009901408 2014 eng d a2191-954200aDiscontinuous two step flow synthesis of m-aminoacetophenone0 aDiscontinuous two step flow synthesis of maminoacetophenone aGENTHINER STRASSE 13, D-10785 BERLIN, GERMANYbWALTER DE GRUYTER GMBHcAUG a279-2850 v33 a

The continuous flow nitration of acetophenone followed by reduction of the meta isomer has been demonstrated using simple tubular reactors. Because of ease of separation of the desired isomer from the first step, both steps are made continuous, but separately. The continuous flow nitration was carried out in a safe manner in a shorter reaction time than the conventional approach. The choice of micromixer was seen to affect the performance of the nitration reaction. The effect of different parameters on the yield of the desired product was studied. The reduction step with sodium sulfide was found to be economical and could be carried out efficiently at 70 degrees C using sodium sulfide in ethanol, using a silicone tube. Both steps were demonstrated for several hours, yielding a sufficiently large quantity (similar to 100 g) of m-aminoacetophenone at lab scale in a single day using simple tubular reactors.

10aacetophenone10acontinuous flow synthesis10amicroreactor10anitration10areduction1 aTibhe, Jagdish1 aSharma, Yachita1 aJoshi, Ramesh, A.1 aJoshi, Rohini, R.1 aKulkarni, Amol, A. uhttps://library.ncl.res.in/content/discontinuous-two-step-flow-synthesis-m-aminoacetophenone-001728nas a2200277 4500008004100000022001400041245009200055210006900147260000800216300001200224490000700236520085900243653002001102653001401122653001701136653000801153653001301161100002001174700002301194700001801217700002801235700001701263700002601280700002301306856012101329 2021 eng d a2062-249X00aDesign and scale-up of continuous di-nitration reaction using pinched tube flow reactor0 aDesign and scaleup of continuous dinitration reaction using pinc cSEP a611-6240 v113 aScale-up of the di-nitration reaction for synthesis of selective herbicide pendimethalin using only nitric acid in continuous flow is presented in this work. This work showcases an approach for smooth scale-up for an herbicide for a production capacity of 50 kg/day using a pinched tube reactor. The approach begins with the batch experiments followed by flow synthesis using a 1/8-inchSS316 helical coil tube where kinetics of the di-nitration was determined, and process optimization was done. Systematic approach was followed for quantification of heat transfer, mass transfer and residence time distribution and scale-up. Detailed scale-up methodology is presented with effect of relevant parameters for successful scale-up. Modular pilot plant with inline quenching, extraction and separation are some of the salient features presented in this work.10acontinuous flow10anitration10aPinched tube10aRTD10ascale-up1 aHussain, Arshad1 aSharma, Mrityunjay1 aPatil, Suneha1 aAcharya, Roopashree, B.1 aKute, Mahesh1 aWaghchaure, Aishwarya1 aKulkarni, Amol, A. uhttps://library.ncl.res.in/content/design-and-scale-continuous-di-nitration-reaction-using-pinched-tube-flow-reactor01362nas a2200157 4500008004100000022001400041245009300055210006900148260000900217300001400226490000700240520079900247100002601046700002301072856010901095 2023 eng d a1359-734500aDirect amidation of acids in a screw reactor for the continuous flow synthesis of amides0 aDirect amidation of acids in a screw reactor for the continuous  cJUL  a9231-92340 v593 a

A simple and efficient solvent-free protocol for continuous flow synthesis of amides at room temperature is developed using easily available starting materials. N-(3-Dimethylaminopropyl)-N & PRIME;-ethylcarbodiimide hydrochloride (EDC.HCl) was used as the reagent for the formation of an amide bond without using any metal catalyst or additives. A jacketed screw reactor when operated over a residence time of 30 300 s helped achieve almost complete conversion. This approach is extended for the synthesis of 36 derivatives and 2 bioactive molecules using different substrates having different aliphatic mono and di-acids as well as aromatic acids, including aromatic hetero-acid compounds and phenyl hydrazine. The target amide was scaled up to 100 g with an average 90% yield.

1 aAtapalkar, Ranjit, S.1 aKulkarni, Amol, A. uhttps://library.ncl.res.in/content/direct-amidation-acids-screw-reactor-continuous-flow-synthesis-amides02363nas a2200157 4500008004100000022001400041245007600055210006900131260000800200300001600208490000700224520182500231100002802056700002302084856009802107 2023 eng d a0743-746300aDynamics of drop formation in the presence of interfacial mass transfer0 aDynamics of drop formation in the presence of interfacial mass t cAUG a12627-126390 v393 a

The dynamics of drop formation have been investigated in the presence of interfacial mass transfer through controlled flow visualization experiments. The mixtures of n-hexane (solvent) and acetone (solute) were used as a dispersed phase, having different initial compositions varying over a broad range. Drops were formed at the submerged position in the continuous phase (water) at the same operating flow conditions. The unsteady force balance model is developed to analyze the implications of the simultaneously occurring interfacial transfer of the solute on the formation dynamics in real time, and predictions are validated with experimental results. Based on initial compositions, the analysis of the transient drop shape shows a sharp transition in the drop formation regime. At lower initial solute concentrations, i.e., phi(0) < 0.2, axisymmetric drop formation occurs and the interfacial solute transfer has negligible effects on the formation dynamics. Over an intermediate range of solute concentrations, i.e., 0.2 < phi(0) < 0.5, Marangoni instability is triggered along the evolving interface, and therefore, the interface deformations and contractions occur during the drop formation. At phi(0) = 0.5, the drop takes highly nonaxisymmetric shapes and remains away from equilibrium until its detachment from an orifice. For phi(0) > 0.5, the spontaneous ejection of plumes of the solute results in the rapid generation of multiple droplets of smaller size. This work shows that higher solute concentration gradients not only lead to faster solute transport but also induce strong interfacial instability simultaneously. Thus, the coupled effects of transient change in composition and fluid properties govern the drop size and its formation time in such systems under non-equilibrium.

1 aKhan, Muzammilanwar, S.1 aKulkarni, Amol, A. uhttps://library.ncl.res.in/content/dynamics-drop-formation-presence-interfacial-mass-transfer