Research On Multidimensional Precise Photoreactor And Photo Continuous Stirred Tank Reactor

The complexity of photochemical processes presents challenges in designing and modeling of appropriate reactors.Photons,as reactants,require different considerations compared to thermochemical reactors.As reactor dimensions increase,the distribution of photons becomes challenging because of the attenuating impact of photon transportation.Micro-structured technologies offer solutions for mass and photonic transfer problems in conventional photochemical units,but further advancements are needed for solid-containing heterogeneous systems.Describing the kinetics of photochemical reactions can be challenging,especially in heterogeneous systems with both thermal and photochemical processes.Most studies focus on small-batch reactors for reaction discovery and optimization,but recent developments have enabled lab-scale continuous-flow photochemistry to be used for large-scale synthesis.However,scaling up to industrially significant quantities has not been achieved yet.Large-scale continuous flow photoreactors for heterogeneous systems are urgently needed in the pharmaceutical industry.In Chapter 2,the development of a precise parallel photoreactor with improved efficiency and reproducibility compared to conventional setups for photocatalyzed reactions has been presented.The key issues with conventional photoreaction setups are low efficiency and poor reproducibility,which were found to be caused by the omission of Lambert’s cosine law and inverse square law,which govern the intensity of light at specific positions.To address these problems,we designed an energyefficient,compact,lab-scale parallel photoreactor that incorporates these optical laws into its design.The new reactor includes a built-in stirrer,temperature control,and the ability to easily change wavelengths.We demonstrated the competence of the new reactor through optical measurements and by comparing the performance of reactions in the new reactor with conventional setups.The new parallel photoreactor showed improved efficiency by reducing reaction time and improving product yield in several reactions,indicating its potential as a standalone compact photoreactor for organic chemistry labs.In Chapter 3,a photo-CSTR(Continuous Stirred Tank Reactor)setup for biphasic and triphasic heterogeneous photo-catalyzed reactions has been introduced.Photocatalysis has found successful applications in a wide range of important transformations.However,the scalability of photocatalytic processes has been hindered by challenges associated with heterogeneous systems involving solids and the limited recyclability of photocatalysts.To address these issues,we have developed a novel approach by designing a multimode photo-CSTR protocol for heterogeneous photocatalytic processes.This new protocol demonstrated exceptional adaptability in accommodating both biphasic(liquid-liquid,liquid-gas,liquid-solid)and triphasic(liquid-solid-gas)processes.Furthermore,we have successfully prepared and evaluated a glass wool-supported uranyl catalyst,which has been recycled at least 12 times without any loss in reactivity in the photocatalyzed hydroxylation of phenylboronic acid.The photo-CSTR design has excellent adaptability for slow or fast kinetic reaction systems.The reactor is capable of processing substantial quantities of solid reaction components and has proven highly effective for reactions on gram-scales.The efficiency of the system in handling solid particles was reaffirmed through a varied Bronsted acid-catalyzed aerobic photo-oxygenation reaction,displaying improved effectiveness when contrasted with conventional batch systems.Additionally,a gramscale photocatalytic multiphase carboxylation reaction was executed smoothly,with no issues related to blockages or clogging.In general,this research provides significant insight in the development of efficient and adaptable photochemical reactors,offering solutions to the challenges in batch and continuous flow photocatalytic processes.