@article { ISI:000332784900001, title = {Continuous flow nitration in miniaturized devices}, journal = {Beilstein Journal of Organic Chemistry}, volume = {10}, year = {2014}, month = {FEB}, pages = {405-424}, publisher = {BEILSTEIN-INSTITUT}, type = {Review}, address = {TRAKEHNER STRASSE 7-9, FRANKFURT AM MAIN, 60487, GERMANY}, abstract = {

This review highlights the state of the art in the field of continuous flow nitration with miniaturized devices. Although nitration has been one of the oldest and most important unit reactions, the advent of miniaturized devices has paved the way for new opportunities to reconsider the conventional approach for exothermic and selectivity sensitive nitration reactions. Four different approaches to flow nitration with microreactors are presented herein and discussed in view of their advantages, limitations and applicability of the information towards scale-up. Selected recent patents that disclose scale-up methodologies for continuous flow nitration are also briefly reviewed.

}, keywords = {continuous flow, flow chemistry, microreactors, nitration, nitric acid, Tubular reactor}, issn = {1860-5397}, doi = {10.3762/bjoc.10.38}, author = {Kulkarni, Amol A.} } @article { ISI:000342087400004, title = {Discontinuous two step flow synthesis of m-aminoacetophenone}, journal = {Green Processing and Synthesis}, volume = {3}, number = {4}, year = {2014}, month = {AUG}, pages = {279-285}, publisher = {WALTER DE GRUYTER GMBH}, type = {Article}, address = {GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY}, abstract = {

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.

}, keywords = {acetophenone, continuous flow synthesis, microreactor, nitration, reduction}, issn = {2191-9542}, doi = {10.1515/gps-2014-0043}, author = {Tibhe, Jagdish and Sharma, Yachita and Joshi, Ramesh A. and Joshi, Rohini R. and Kulkarni, Amol A.} } @article { ISI:000337539000009, title = {Evaluation of multipoint dosing strategy in a miniaturized tubular reactor: nitration of salicylic acid}, journal = {Chemical Engineering \& Technology}, volume = {37}, number = {6}, year = {2014}, month = {JUN}, pages = {927-937}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

A 2D non-isothermal reaction engineering model for a tubular reactor was developed for a complex reaction network of salicylic acid nitration. The influence of different operating and design parameters was studied to minimize the amount of secondary nitration products and limit the maximum temperature inside the reactor. Critical temperature effects were observed for larger reaction tubes, whereas close to isothermal conditions were perceived in smaller tubes. With single-point dosing of both reactants, complete conversion can be achieved but formation of secondary nitration products cannot be avoided. For a given number of dosing points, a suitable combination of the operating parameters allowed to achieve complete conversion and better yield of the desired product.

}, keywords = {Multipoint injection, nitration, Plug-flow reactor, Salicylic acid, Tubular reactor}, issn = {0930-7516}, doi = {10.1002/ceat.201300427}, author = {Debnath, Soujoy and Kienle, Achim and Kulkarni, Amol A.} } @article {47591, title = {Design and scale-up of continuous di-nitration reaction using pinched tube flow reactor}, journal = {Journal of Flow Chemistry}, volume = {11}, year = {2021}, month = {SEP}, pages = {611-624}, type = {Article}, abstract = {Scale-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.}, keywords = {continuous flow, nitration, Pinched tube, RTD, scale-up}, issn = {2062-249X}, doi = {10.1007/s41981-021-00182-1}, author = {Hussain, Arshad and Sharma, Mrityunjay and Patil, Suneha and Acharya, Roopashree B. and Kute, Mahesh and Waghchaure, Aishwarya and Kulkarni, Amol A.} }