A novel micro-flow system under microwave irradiation for continuous synthesis of 1,4-dihydropyridines in the absence of solvents via Hantzsch reaction
“…MW-assisted flow synthesis of 1,3-thiazine ( 5 ) to corresponding hydropyrimidine( 6 ) was reported by Glasnov et al., in 2006 (Glasnov et al., 2006). Recently, continuous MW-assisted flow synthesis of 1,4-dihydropyridines ( 7 ) was achieved using microflow system over γ-Fe 2 O 3 NPs prepared using valve-assisted micromixer ( He et al., 2018 ). Microwave flow systems other than organic synthesis also showed applications in synthesis and fabrication of polyesters and nanoparticles ( Ching Lau et al., 2019 ; Bayazit et al., 2016 ).…”
Section: Importance Of Flow Chemistrymentioning
confidence: 99%
“… Figure 3 Continuous flow synthesis under MW, light and supercritical conditions Figure were adapted/reproduced with the permission from Wegner et al. (2011) (RSC); He et al. (2018) (Elsevier) and Baeten et al.…”
“…MW-assisted flow synthesis of 1,3-thiazine ( 5 ) to corresponding hydropyrimidine( 6 ) was reported by Glasnov et al., in 2006 (Glasnov et al., 2006). Recently, continuous MW-assisted flow synthesis of 1,4-dihydropyridines ( 7 ) was achieved using microflow system over γ-Fe 2 O 3 NPs prepared using valve-assisted micromixer ( He et al., 2018 ). Microwave flow systems other than organic synthesis also showed applications in synthesis and fabrication of polyesters and nanoparticles ( Ching Lau et al., 2019 ; Bayazit et al., 2016 ).…”
Section: Importance Of Flow Chemistrymentioning
confidence: 99%
“… Figure 3 Continuous flow synthesis under MW, light and supercritical conditions Figure were adapted/reproduced with the permission from Wegner et al. (2011) (RSC); He et al. (2018) (Elsevier) and Baeten et al.…”
“…This type of promotion is not usually accessible by classical heating and the polarizing radiation involving non-thermal effects. [42][43][44] In this area, the existence of numerous reports in literature shows the importance of microwave radiation towards synthesis of various materials [45][46][47][48][49][50][51][52] as well as 1,4-dihydropyridines [53][54][55][56][57] in dry or solution media.…”
In this study, a green and practical approach towards Hantzsch dihydropyridine synthesis of acridine-1,8-diones is introduced. Via the mentioned protocol, the one-pot condensation reaction of structurally diverse aromatic aldehydes, dimedone and NH4OAc was promoted by microwave radiation at solvent and catalyst-free conditions. Consequently, acridinedione products were produced in 81-97% yields within 3-8 min. The current protocol represents the prominent advantages in terms of the using a simple synthetic procedure, short reaction times, mild reaction conditions, high yield of the products as well as omission of hazardous and costeffective organic solvents/reagents.
“…These miniaturized systems not only offer accurate fluid control, but also exhibit excellent heat and mass transfer properties as a result of their large surface-to-volume ratio [6][7][8]. In microfluidic systems, the solid catalyst can be introduced as a packed bed [9,10], a monolithic phase (foam) [11,12], or a thin-layer on the microchannel walls [13,14]. Furthermore, and particularly, reactions suffering from slow kinetics benefit from the large catalytic surface area offered by microreactors.…”
In heterogeneous catalysis, the creation of gaseous products as bubbles in a liquid phase on the catalytic surface is associated with slip phenomena. In a microreactor, the slip length at the gas‐liquid interface is in the same order of magnitude as the reactor dimensions, which can affect fluid dynamics and transport phenomena. Here, the interplay of momentum, heat and mass transfer in a microreactor, when bubbles form on the catalytic surface, was investigated using two‐dimensional simulations. The effect of bubbles on the endothermic process of aqueous‐phase reforming of a glycerol solution was evaluated in terms of conversion and conversion and temperature in the reactor. Altogether, this study highlights the impact of bubbles, not only on the transport phenomena but also on the reactor performance.
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