Abstract
Abstract Millireactors offer the same advantages of microreactors, which are high surface to volume ratios and low Reynolds numbers (laminar flow). Polymerization reactions concerning high heat quantities and so it is an excellent example of medium that can be used in microreactors. The Syrris ASIA millireactor, 4.0 mL volume, was employed for the polymerization of styrene in toluene, performed at 100 °C and 115 °C. The objective is to produce polystyrene with the view of making the production more efficient. Different reagent quantities and residence times were used. Monomer conversions reached 67%, while number average molecular weight varied from 6000 to 50,000 g/mol. No plugging occurred, allowing more aggressive applications. The mass of the polymer product formed per volume of the reactor and time is about 0.1 kg/m 3 /s, which is higher than the values of the batch reactor (0.019 kg/m 3 /s) and of the tubular reactor (0.029 kg/m 3 /s). The fluid dynamic was evaluated as well by assuming reactor models. The PFR and the dispersion models were used to simulate the outputs, and gave a good forecast except for higher monomer contents, with larger polydispersities. To understand the microfluidic, the polymerization kinetic was also studied, using the full molecular weight distribution.
Highlights
Microstructured reactors are devices with three-dimensional structures, whose inner dimensions are under a millimeter in size, and between ten and a hundred micrometers. Process parameters such as pressure, temperature, residence time and flow rate are more controlled in reactions that take place in small volumes (Jähnisch et al, 2004)
Iwasaki and Yoshida (2005) already performed polymerizations with a 0.5 mm reactor and concluded that microreactors are quite effective for molecular weight distribution control for highly exothermic free radical polymerization, while improvements are less evident for less exothermic ones
The syringe pumps modulus, where two syringes for each pump allowed a feed injection into the reactor from 10 μl/min up to 2.5 ml/min
Summary
Microstructured reactors are devices with three-dimensional structures, whose inner dimensions are under a millimeter in size, and between ten and a hundred micrometers. Process parameters such as pressure, temperature, residence time and flow rate are more controlled in reactions that take place in small volumes (Jähnisch et al, 2004). Millireactors have smaller surface to volume ratio but can present advantages compared to the microreactors, with improved flow capacities ( higher productivity), lower pressure drops and lower tendency to block. In 2011 Mandal et al studied a coiled configuration of a 2 mm millireactor and observed a higher conversion and satisfactory polymer molecular weights, due to a better mixing caused by the reactor curves
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