scholarly journals Process Intensification for the Synthesis of 6-Allyl-6-azabicyclo[3.1.0]hex-3-en-2-ol from 1-Allylpyridinium Salt Using a Continuous UV-Light Photoflow Approach

2019 ◽  
Vol 2 (3) ◽  
pp. 67 ◽  
Author(s):  
Milene A. G. Fortunato ◽  
Chi-Phong Ly ◽  
Filipa Siopa ◽  
Carlos A. M. Afonso
Keyword(s):  
Continuous Flow ◽  
Flow Reactor ◽  
Uv Light ◽  
Continuous Production ◽  
Continuous Process ◽  
Reaction Times ◽  
Process Intensification ◽  
Internal Diameter ◽  
Irradiation Zone ◽  
Photochemical Transformations

A new home-made UV photochemical reactor (95 cm of irradiation zone) consisting of a 12 parallel quartz tubes flow reactor, PQT6 (95 cm under irradiation and an internal diameter of 0.6 cm) was assembled to perform photochemical transformations in continuous-flow. PQT6 was evaluated for the photoreaction of 1-allylpyridinium bromide (1a) to 6-allyl-6-azabicyclo[3.1.0]hex-3-en-2-ol (2a), in a continuous process. This technology provides reduced reaction times, continuous production of 2a, and a productivity of 129 mg h−1, corresponding to 1.94 g of isolated 2a after 15 h of irradiation.

scholarly journals Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

2013 ◽  
Vol 9 ◽  
pp. 2886-2897 ◽  
Author(s):  
Phei Li Lau ◽  
Ray W K Allen ◽  
Peter Styring
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Methyl Acrylate ◽  
Heck Reaction ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Product Distribution ◽  
Internal Diameter ◽  
Palladium Metal ◽  
Supercritical Carbon

The palladium metal catalysed Heck reaction of 4-iodoanisole with styrene or methyl acrylate has been studied in a continuous plug flow reactor (PFR) using supercritical carbon dioxide (scCO2) as the solvent, with THF and methanol as modifiers. The catalyst was 2% palladium on silica and the base was diisopropylethylamine due to its solubility in the reaction solvent. No phosphine co-catalysts were used so the work-up procedure was simplified and the green credentials of the reaction were enhanced. The reactions were studied as a function of temperature, pressure and flow rate and in the case of the reaction with styrene compared against a standard, stirred autoclave reaction. Conversion was determined and, in the case of the reaction with styrene, the isomeric product distribution was monitored by GC. In the case of the reaction with methyl acrylate the reactor was scaled from a 1.0 mm to 3.9 mm internal diameter and the conversion and turnover frequency determined. The results show that the Heck reaction can be effectively performed in scCO2 under continuous flow conditions with a palladium metal, phosphine-free catalyst, but care must be taken when selecting the reaction temperature in order to ensure the appropriate isomer distribution is achieved. Higher reaction temperatures were found to enhance formation of the branched terminal alkene isomer as opposed to the linear trans-isomer.

scholarly journals Diels–Alder reactions of myrcene using intensified continuous-flow reactors

2017 ◽  
Vol 13 ◽  
pp. 120-126 ◽  
Author(s):  
Christian H Hornung ◽  
Miguel Á Álvarez-Diéguez ◽  
Thomas M Kohl ◽  
John Tsanaktsidis
Keyword(s):  
Continuous Flow ◽  
Flow Reactor ◽  
Scale Up ◽  
Reaction Times ◽  
Alder Reaction ◽  
Diels Alder ◽  
Flow Reactors ◽  
Diels Alder Reaction ◽  
Naturally Occurring ◽  
Continuous Flow Reactors

This work describes the Diels–Alder reaction of the naturally occurring substituted butadiene, myrcene, with a range of different naturally occurring and synthetic dienophiles. The synthesis of the Diels–Alder adduct from myrcene and acrylic acid, containing surfactant properties, was scaled-up in a plate-type continuous-flow reactor with a volume of 105 mL to a throughput of 2.79 kg of the final product per day. This continuous-flow approach provides a facile alternative scale-up route to conventional batch processing, and it helps to intensify the synthesis protocol by applying higher reaction temperatures and shorter reaction times.

scholarly journals Photo-catalytic degradation of polyphenolic tannins in continuous-flow reactor using titanium dioxide immobilized on a cellulosic material

2020 ◽  
Vol 82 (7) ◽  
pp. 1454-1466
Author(s):  
Abdelhadi Jouali ◽  
Anas Salhi ◽  
Abdelkahhar Aguedach ◽  
El Kbir Lhadi ◽  
Mohammed El Krati ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Uv Light ◽  
Catalytic Degradation ◽  
Light Irradiation ◽  
Maximum Efficiency ◽  
Environmental Damage ◽  
Continuous Flow Reactor ◽  
Uv Light Irradiation

Abstract Tannins are recalcitrant polyphenolic molecules that resist microbial attack. Their main environmental damage is due to their low biodegradability. This work aims to investigate the photo-catalytic degradation of two commercial tannin extracts, chestnut (hydrolysable tannin) and mimosa (condensed tannin). The experiments were carried out under UV-light irradiation in a continuous-flow reactor using titanium dioxide (TiO2) immobilized on cellulosic fibers. It was highlighted that photo-catalytic degradation is unfavourable in acidic medium and when the pH is too high (pH above 12); it reaches its maximum efficiency at pH 7.5 (99 and 97% for chestnut and mimosa, respectively). Nearly complete degradation of tannins requires an irradiation period of 6 h. The process efficiency is inversely affected by the concentration of tannins essentially above 75 mg/L for chestnut and 60 mg/L for mimosa. Above 240 mL/min, any increase in feed flow negatively affects the performance of the process. Furthermore, a significant decrease of treatment efficiency was seen when increasing the concentration of ethanol and salts in the medium. Obtained results suggest that UV-light irradiation in a continuous-flow photo-reactor using immobilized TiO2 may be considered as an adequate process for the treatment of water containing recalcitrant tannin molecules.

The Influence of Residence Time Distribution on Continuous Flow Polymerization

2019 ◽  
Author(s):  
Marcus Reis ◽  
Travis Varner ◽  
Frank Leibfarth
Keyword(s):  
Residence Time ◽  
Continuous Flow ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Flow Reactor ◽  
Continuous Production ◽  
Flow Chemistry ◽  
Statistical Correlations ◽  
Tubular Reactors ◽  
Vis Spectroscopy

<p>Continuous-flow chemistry is emerging as an enabling technology for the synthesis of precise polymers. Despite recent advances in this rapidly growing field, there remains a need for a fundamental understanding of how fluid dynamics in tubular reactors influence polymerizations. Herein, we report a comprehensive study of how laminar flow influences polymer structure and composition. Tracer experiments coupled with in-line UV-vis spectroscopy demonstrate how viscosity, tubing diameter, and reaction time affect the residence time distribution (RTD) of fluid in reactor geometries relevant for continuous-flow polymerizations. We found that the breadth of the RTD has strong, statistical correlations with reaction conversion, polymer molar mass, and dispersity for polymerizations conducted in continuous flow. These correlations were demonstrated to be general to a variety of different reaction conditions, monomers, and polymerization mechanisms. Additionally, these findings inspired the design of a droplet flow reactor that minimizes the RTD in continuous-flow polymerizations and enables the continuous production of well-defined polymer at a rate of 1.4 kg/day. </p>

Treatability of Phenol by Supercritical Water Oxidation

2011 ◽  
Vol 422 ◽  
pp. 462-465
Author(s):  
Hui Li ◽  
En Zhao
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Reaction Times ◽  
Supercritical Water Oxidation ◽  
Continuous Flow Reactor ◽  
Organic Destruction ◽  
Water Conditions ◽  
Phenol Wastewater

This study focused on the treatment of phenol wastewater by supercritical water oxidation(SCWO). Tests were conducted by using a continuous-flow reactor system. Based on COD, organic destruction efficiencies of phenol wastewater were obtained at supercritical water conditions. Temperatures and pressures, respectively, ranged from 400-500°C,and 25-40Mpa. The reaction times varied from 30 to 190 seconds, and hydrogen peroxide was used as oxidant. Under SCWO conditions, destruction efficiencies greater than 99% were achieved.

scholarly journals Boosting the Productivity of H2-Driven Biocatalysis in a Commercial Hydrogenation Flow Reactor Using H2 From Water Electrolysis

2021 ◽  
Vol 3 ◽  
Author(s):  
Barnabas Poznansky ◽  
Sarah E. Cleary ◽  
Lisa A. Thompson ◽  
Holly A. Reeve ◽  
Kylie A. Vincent
Keyword(s):  
Continuous Flow ◽  
Room Temperature ◽  
Immobilized Enzyme ◽  
Flow Reactor ◽  
Process Intensification ◽  
Water Electrolysis ◽  
Turnover Frequency ◽  
Batch Mode ◽  
Hydrogenation Reactions ◽  
Redox Biocatalysis

Translation of redox biocatalysis into a commercial hydrogenation flow reactor, with in-built electrolytic H2 generation, was achieved using immobilized enzyme systems. Carbon-supported biocatalysts were first tested in batch mode, and were then transferred into continuous flow columns for H2-driven, NADH-dependent asymmetric ketone reductions. The biocatalysts were thus handled comparably to heterogeneous metal catalysts, but operated at room temperature and 1–50 bar H2, highlighting that biocatalytic strategies enable implementation of hydrogenation reactions under mild–moderate conditions. Continuous flow reactions were demonstrated as a strategy for process intensification; high conversions were achieved in short residence times, with a high biocatalyst turnover frequency and productivity. These results show the prospect of using enzymes in reactor infrastructure designed for conventional heterogeneous hydrogenations.

scholarly journals UV Light Driven Selective Oxidation of Cyclohexane in Gaseous Phase Using Mo-Functionalized Zeolites

Surfaces ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 546-559 ◽  
Author(s):  
Vincenzo Vaiano ◽  
Diana Sannino
Keyword(s):  
Gas Phase ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Uv Light ◽  
Heterogeneous Photocatalysis ◽  
Reaction Products ◽  
Promising Technique ◽  
Total Oxidation ◽  
Mild Conditions ◽  
Continuous Flow Reactor

Heterogeneous photocatalysis in the gas phase has been applied as a promising technique for organic syntheses in mild conditions. Modified zeolites have been used under UV irradiation as novel photocatalysts. In this study, we preliminarily investigated the photoxidation of cyclohexane on ferrierite and MoOx-functionalized ferrierite in a gas–solid continuous flow reactor. In the presence of UV light, MoOx-functionalized ferrierite showed the formation of benzene and cyclohexene as reaction products, indicating the occurrence of photocatalysed cyclohexane oxydehydrogenation. By contrast, unmodified ammonium ferrierite exhibited relevant activity for total oxidation of cyclohexane to carbon dioxide and water. The influence of Mo loading on cyclohexane conversion and products selectivity was evaluated.

The Influence of Residence Time Distribution on Continuous Flow Polymerization

2019 ◽  
Author(s):  
Marcus Reis ◽  
Travis Varner ◽  
Frank Leibfarth
Keyword(s):  
Residence Time ◽  
Continuous Flow ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Flow Reactor ◽  
Continuous Production ◽  
Flow Chemistry ◽  
Statistical Correlations ◽  
Tubular Reactors ◽  
Vis Spectroscopy

<p>Continuous-flow chemistry is emerging as an enabling technology for the synthesis of precise polymers. Despite recent advances in this rapidly growing field, there remains a need for a fundamental understanding of how fluid dynamics in tubular reactors influence polymerizations. Herein, we report a comprehensive study of how laminar flow influences polymer structure and composition. Tracer experiments coupled with in-line UV-vis spectroscopy demonstrate how viscosity, tubing diameter, and reaction time affect the residence time distribution (RTD) of fluid in reactor geometries relevant for continuous-flow polymerizations. We found that the breadth of the RTD has strong, statistical correlations with reaction conversion, polymer molar mass, and dispersity for polymerizations conducted in continuous flow. These correlations were demonstrated to be general to a variety of different reaction conditions, monomers, and polymerization mechanisms. Additionally, these findings inspired the design of a droplet flow reactor that minimizes the RTD in continuous-flow polymerizations and enables the continuous production of well-defined polymer at a rate of 1.4 kg/day. </p>

Renewable Energy from Agricultural Waste

2018 ◽  
Vol 69 (6) ◽  
pp. 1363-1366 ◽  
Author(s):  
Stefania Daniela Bran ◽  
Petre Chipurici ◽  
Mariana Bran ◽  
Alexandru Vlaicu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gas Chromatography ◽  
Continuous Flow ◽  
Laboratory Experiments ◽  
Fermentation Process ◽  
Flow Reactor ◽  
Agricultural Waste ◽  
Continuous Flow Reactor ◽  
Natural Support ◽  
Co2 Flow

This paper has aimed at evaluating the concentration of bioethanol obtained using sunflower stem as natural support, molasses as carbon source and Saccharomyces cerevisiae yeast in a continuous flow reactor. The natural support was tested to investigate the immobilization/growth of S. cerevisiae yeast. The concentration of bioethanol produced by fermentation was analyzed by gas chromatography using two methods: aqueous solutions and extraction in organic phase. The CO2 flow obtained during the fermentation process was considered to estimate when the yeast was deactivated. The laboratory experiments have highlighted that the use of plant-based wastes to bioconversion in ethanol could be a non-pollutant and sustainable alternative.

Thermocatalytic Hydrodeoxygenation and Depolymerization of Waste Lignin to Oxygenates and Biofuels in a Continuous Flow Reactor at Atmospheric Pressure

2020 ◽  
Vol 8 (35) ◽  
pp. 13195-13205 ◽  
Author(s):  
Swathi Mukundan ◽  
Daria Boffito ◽  
Abhijit Shrotri ◽  
Luqman Atanda ◽  
Jorge Beltramini ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Continuous Flow Reactor
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