Automated Continuous Flow Reactor for the Mass Production of Photoluminescent Nanoparticles

E. Simsek, O.V. Akgun, E. Heves, L. Dogan, I. Hocaoglu, P. Dagtepe, N. Sezen, H.T. Ruzgar
Kuantag Nanoteknolojiler Gelistirme ve Uretim A. S.,

Keywords: flow reactor, photoluminescent nanoparticle, quantum dot, automation


Batch and flow reactors are two most common production methods employed widely in various chemical industries. The main advantage of flow reaction systems over batch reactors is the continuous production capability. Besides, particularly for the production of fine chemicals where efficient mass and heat transfer is crucial for homogenous reaction kinetics, flow reactor channels offer much to improve product quality without altering the production capacity in comparison to bulky batch systems. As an example to fine chemicals production, nanoparticle synthesis require good reaction kinetics control since small differences in elemental composition and particle geometry may have drastic effects on overall product properties. Accordingly, in the past 15 years, a number of efforts has been showed for developing flow reactor technologies which are suitable for mass production of nanoparticles with a feasible “scaling up without drawbacks in the product quality” perspective. Flow reactors also offer various flexibilities for better process designs. One of the popular applications is separating the production line into different reaction segments, for instance, employing different heating regions for particle nucleation, growth and shell/coating addition step for a core/shell nanoparticle, a quenching step for stabilizing the final particles, and etc. To control the final product quality, spectroscopic characterization is required during or after each reaction step so that appropriate actions can be taken accordingly. Most of the time, employment of flow cells are required for this purpose since the polymeric or metal tubings used widely as reaction platforms in conventional flow reactors are either opaque or slightly transparent for in-line spectroscopic characterization. These flow cells are likely to lead to formation of dead volumes in the production line and have the risk of introducing regular product contaminations and quality control problems. To overcome these drawbacks, we have developed a process that makes use of glass reaction modules which are radiation transparent, and also have non-linear channel geometries which provide good mixing and good heat transfer during the entire reaction interval. Although new features introduce various useful options to process design, they also bring about new challenges in terms of process control. Recently, several flow reactor systems were introduced with computer control but still leaving many gaps in terms of automation since most decisions are left to operator. Another superiority of our process is that all the mechanical parts, monitoring and control equipments work in coordination to realize a complex production plan of multiple recipes by self-optimizing each final product using the characterization data. Our unique approach in fully automated, continuous flow process design would bring new aspects to nanoparticle mass production.