@article {46206, title = { Exploring the steady operation of a continuous pilot plant for the di-nitration reaction }, journal = {Chemical Engineering \& Technology}, year = {2019}, month = {AUG}, type = {Article; Early Access}, abstract = {

Continuous-flow synthesis of the selective herbicide pendimethalin was demonstrated in both a laboratory-scale and a pilot-scale reactor using only concentrated nitric acid as nitrating agent. The di-nitration reaction follows second-order kinetics where the reaction is first order with respect to both reactant and nitric acid. The pinched-tube reactor was chosen for pilot-scale reactor fabrication due to its excellent mixing and mass transfer characteristics compared to a straight-tube reactor. The estimated mass transfer coefficient showed similar nature in the laboratory-scale and the pilot-scale pinched-tube reactor, ensuring similar performance at the pilot scale. Di-nitration in continuous flow, inline quenching, extraction, and phase separation are some of the salient features of the developed pilot plant. The importance of the start-up time for achieving steady state in the flow system at the large scale is highlighted.

}, doi = {10.1002/ceat.201900140}, author = {Sharma, Mrityunjay and Acharya, Roopashree B. 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.} }