@article {48731, title = {Effect of microwave heating on the residence time distribution in a tubular reactor}, journal = {Industrial \& Engineering Chemistry Research}, volume = {62}, year = {2023}, month = {AUG }, pages = {19381-19389}, type = {Article}, abstract = {

Microwave(MW) heating has been revolutionary in various applications,including chemical synthesis. A nonconventional heating approach reducesthe reaction time significantly. For a continuous flow tubular reactorunder microwaves, the temperature would change from the inlet to theoutlet depending on the dielectric constant of the reaction mass,which would further change the physical properties, viz., the densityand viscosity of the material. Such changes in the physical propertieswould lead to nonideal flows and would affect the conversion as wellas selectivity for reactions. In order to understand the extent ofsuch a nonideality, here for the first time we have done systematicstudies of the residence time distribution in a helical coil reactor.The axial dispersion model has been modified to take into accountthe temperature-dependent physical properties of the fluid. The empiricalcorrelation for the dispersion number is obtained over the range of450 \& LE; P (W) \& LE; 1200 and 60 \& LE; T (\& DEG;C) \& LE; 150. This study will help model thereaction kinetics as well as reactor design under microwave specificallyfor heat sensitive reactions where variations in the overall residencetime would affect the yield and selectivity of the end product.

}, issn = {0888-5885}, doi = {10.1021/acs.iecr.3c01243}, author = {Sonawane, Jayesh R. and Kulkarni, Amol A.} } @article {48706, title = {Understanding the nucleation and growth kinetics of the microwave-assisted synthesis of silver nanowires}, journal = {Industrial \& Engineering Chemistry Research}, volume = {62}, year = {2023}, month = {SEP }, pages = {14199-14211}, type = {Article}, abstract = {

Here, we present a detailed study of understanding the nucleation and growth kinetics of silver nanowire synthesis under microwave irradiation. The approach includes studying the effect of various parameters (viz., microwave power, reaction temperature, reaction time, substrate concentration, etc.) on the rate of nucleation and growth, as well as on the yield and morphology of silver nanowires. It is found that microwave power is the most important factor in leading to almost complete conversion of the substrate along with high aspect ratio nanowires in a short reaction time. Based on the observations, here, we have proposed a three-step growth kinetics mechanism for the synthesis of silver nanowires under the influence of microwaves. The approach comprises the autocatalytic growth of stable multiple twin particles after the nucleation process and their unidirectional growth to form nanowires. The FW autocatalytic model and the JMAK Avrami model were used to validate the proposed mechanism of AgNW formation based on our experimental results. The model predictions match very well with the conversion and yield of AgNWs. At the optimized conditions, wires with a 42 nm diameter and 94\% yield were achieved within 4 min.

}, issn = {0888-5885}, doi = {10.1021/acs.iecr.3c00322}, author = {Sonawane, Jayesh R. and Patil, Suneha and Kulkarni, Amol A.} } @article {49319, title = {Model predicted optimization of experimental set-up and process conditions for microwave-assisted synthesis of silver nanowires}, journal = {Chemical Engineering Journal}, volume = {498}, year = {2024}, month = {OCT}, pages = {155483}, type = {Article}, abstract = {

This work presents simulations led optimization of choice of a reactor for an experimental set-up for the continuous production of silver nanowires with certain constraints in terms of yield, reaction time, and dimensions of nanowires. The choice of reactors based on the simulations of reaction kinetics for nucleation and growth phases of driving the optimization of an experimental set-up and subsequent optimization of process conditions to maximize the yield of nanowires of desired dimensions. The optimized reactor configuration is dictated by the reaction kinetics and using a microwave in continuous mode becomes unavoidable. This makes the approach highly reproducible as well as scalable. The integration of conventional and microwave heating is simulated and subsequently optimized experimentally to attain a significant increase in nanowire yield under steady-state conditions with less than 15 min of residence time. The precise control over the rate in different reactor configurations governing nucleation, accelerated growth followed by slow growth to complete the conversion of precursor enables higher selectivity of nanowires with controllable dimensions resulting in 100 gm production per day using simple set-up. We systematically examined key reaction parameters, including the concentration of metal ions, residence time, and different reactor configurations. Our approach successfully yielded AgNWs with 40-60 nm diameter and 15 mu m length. The cost associated with this process for synthesizing AgNWs is less than 10\$ per gram. This study highlights the potential of continuous, high-throughput processes for controlling nanowire size and yield through advanced reactor engineering.

}, keywords = {Continuous synthesis, Microwave, Reactor design, Silver Nanowires}, issn = {1385-8947}, doi = {10.1016/j.cej.2024.155483}, author = {Sonawane, Jayesh R. and Kulkarni, Amol A.} } @article {49259, title = {Scaling-up continuous production of mesoporous silica particles at kg scale: design \& operational strategies}, journal = {Reaction Chemistry \& Engineering}, volume = {9}, year = {2024}, month = {JUN }, pages = {1914-1923}, type = {Article}, abstract = {

This paper demonstrates a continuous flow pilot-scale production of highly porous mesoporous silica particles (MSPs) via a soft template based technique. The study presents pilot scale reactor design, fabrication and production of mesoporous silica particles with a 1 kg per day production rate. The extent of mixing and overall performance of the system were evaluated by conducting a hydrodynamic study, including the estimation of the heat transfer coefficient and dispersion number. Nanoparticle synthesis in a clogging-free manner is the key challenge in moving towards large scale production and commercial applications. This article presents a comprehensive study on the effect of key parameters for successful scaling up of the process. We have also addressed challenges faced and how these are overcome by troubleshooting the process. Different strategies were used to prevent the clogging of the reactor, which involved reactant dilution, periodic pulsation and slug flow (two phase flow). Among them, slug flow allows us to operate the reactor continuously for several hours without clogging and wall-deposition problems. It helped produce morphologically well-defined and near-monodisperse particles. With this process, the production is validated at a scale of 85 times compared to that of a laboratory system (from 22 mL to \>1.5 L), enabling a production rate of 20-50 g h(-1).

}, issn = {2058-9883}, doi = {10.1039/d3re00707c}, author = {Jundale, Rajashri B. and Sonawane, Jayesh R. and Palghadmal, Anil V. and Jaiswal, Hemant Kumar and Deore, Hital S. and Kulkarni, Amol A.} } @article {49609, title = {Continuous flow synthesis of metal nanowires: protocols, engineering aspects of scale-up and applications}, journal = {Materials Horizons}, volume = {12}, year = {2025}, month = {JAN}, pages = {364-400}, type = {Review}, abstract = {

This review comprehensively covers the translation from batch to continuous flow synthesis of metal nanowires (i.e., silver, copper, gold, and platinum nanowires) and their diverse applications across various sectors. Metal nanowires have attracted significant attention owing to their versatility and feasibility for large-scale synthesis. The efficacy of flow chemistry in nanomaterial synthesis has been extensively demonstrated over the past few decades. Continuous flow synthesis offers scalability, high throughput screening, and robust and reproducible synthesis procedures, making it a promising technology. Silver nanowires, widely used in flexible electronics, transparent conductive films, and sensors, have benefited from advancements in continuous flow synthesis aimed at achieving high aspect ratios and uniform diameters, though challenges in preventing agglomeration during large-scale production remain. Copper nanowires, considered as a cost-effective alternative to silver nanowires for conductive materials, have benefited from continuous flow synthesis methods that minimize oxidation and enhance stability, yet scaling up these processes requires precise control of reducing environments and copper ion concentration. A critical evaluation of various metal nanowire ink formulations is conducted, aiming to identify formulations that exhibit superior properties with lower metal solid content. This study delves into the intricacies of continuous flow synthesis methods for metal nanowires, emphasizing the exploration of engineering considerations essential for the design of continuous flow reactors. Furthermore, challenges associated with large-scale synthesis are addressed, highlighting the process-related issues. This review comprehensively covers the translation from batch to continuous flow synthesis of metal nanowires (i.e., silver, copper, gold, and platinum nanowires) and their diverse applications across various sectors.

}, issn = {2051-6347}, doi = {10.1039/d4mh00781f}, author = {Sonawane, Jayesh R. and Jundale, Rajashri and Kulkarni, Amol A.} }