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Search for "biphasic reactions" in Full Text gives 5 result(s) in Beilstein Journal of Organic Chemistry.
A method to determine the correct photocatalyst concentration for photooxidation reactions conducted in continuous flow reactors
- Clemens R. Horn and
- Sylvain Gremetz
Beilstein J. Org. Chem. 2020, 16, 871–879, doi:10.3762/bjoc.16.78
- little as possible” [8]. This phrase describes the approach used to scale up flow reactors to an industrial scale [9][10]. This is particularly true when it comes to biphasic reactions, like a gas/liquid reaction as is the case for photooxidations [11]. An interesting aspect of photooxidations is that
Graphical Abstract
Figure 1: Reaction setup (FC: flow controller, BPR: back pressure regulator).
Scheme 1: Photocatalysts A–I screened for the oxidation of citronellol.
Figure 2: Conversion and transmission at fixed reaction conditions (0.5 N citronellol, 1 mL/min,1 mol % catal...
Figure 3: Measured transmission spectrum of a 5 mmol/L (1 mol %) solution of TPP (H) in dichloromethane with ...
Figure 4: Transmission spectra of rose bengal (D) and the emission spectrum of an LED with a maximum at 524 n...
Figure 5: Transmission spectra of dimethylanthracene (Gb) and emission spectra of LEDs with maxima at 365, 37...
Figure 6: Transmission spectra of TPP (H) and emission spectra of LEDs with maxima at 407 and 424 nm, respect...
Scheme 2: Photooxidation of alpha-terpinene.
Figure 7: Conversion of alpha-terpinene using the wavelength-adapted TPP (H) concentrations.
Figure 8: Conversion of alpha-terpinene at different TPP (H) concentrations.
Figure 9: Conversion of alpha-terpinene (0.5 N) as a function of the wavelength using DMA (Gb) as the catalys...
Figure 10: Conversion of citronellol at different concentrations of rose bengal (D).
Figure 11: Conversion of citronellol as a function of the light power (0.5 mol/L of citronellol, 1.34 mmol/L r...
Figure 12: Absolute conversion of various concentrations of alpha-terpinene at 407 nm using 0.32 mmol/L of TPP...
A flow reactor setup for photochemistry of biphasic gas/liquid reactions
- Josef Schachtner,
- Patrick Bayer and
- Axel Jacobi von Wangelin
Beilstein J. Org. Chem. 2016, 12, 1798–1811, doi:10.3762/bjoc.12.170
- operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories. Keywords: biphasic reactions; flow chemistry; gas phase; microreactor; oxygen; photochemistry; Introduction The recent developments of microreactor technologies have significantly
Graphical Abstract
Figure 1: The challenge of mixing the three dispersed entities gas, liquid, and light for photochemical appli...
Scheme 1: Mutual interdependencies of critical reaction and reactor parameters.
Scheme 2: Blueprint of the home-built microflow photoreactor; schematic illustration of the reactor setup wit...
Figure 2: Total absorbance of methylene blue solutions in acetonitrile according to the Beer-Lambert law: Eλ ...
Figure 3: Red (λmax = 633 nm), blue (λmax = 448 nm), green (λmax = 520 nm) and white (λmax = 620 nm) LEDs mou...
Figure 4: Overlap of absorption spectrum of methylene blue in acetonitrile and emission spectra of reasonably...
Figure 5: Emission spectra of different LEDs; red (λmax = 633 nm), blue (λmax = 448 nm), green (λmax = 520 nm...
Scheme 3: Slug flow conditions of two-phase gas-liquid mixtures. Photograph of a slug flow of a solution of m...
Figure 6: Photograph of the operating flow reactor, irradiated with white LEDs, filled with a solution of met...
Scheme 4: Schematic illustration of a reactor tube (length l, inner diameter d) and pressure gradient Δp acco...
Scheme 5: Reaction types of organic molecules with singlet oxygen.
Figure 7: Home-made flow reactor and peripheral devices for photochemical reactions at light/liquid/gas inter...
Scheme 6: Photooxygenation of N-methyl-1,2,3,6-tetrahydrophthalimide and reductive work-up to alcohol 3a.
Figure 8: Conversion vs methylene blue sensitizer concentration. Reactions at constant flow rates in acetonit...
Figure 9: Reaction progress at different residence times in flow and batch reactions. Flow: reactions at diff...
Scheme 7: Oxidation of N-methyl-1,2,3,6-tetrahydro-3-acetamidophthalimide and reductive work-up to alcohol 3b....
Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors
- A. John Blacker and
- Katherine E. Jolley
Beilstein J. Org. Chem. 2015, 11, 2408–2417, doi:10.3762/bjoc.11.262
- the two liquid phases that limits the rate of product formation, rather than the chemical rate of reaction between the two species. Continuous liquid biphasic reactions are usually poorly mixed within micro-scale reactors, as low fluid velocities and frictional wall effects cause laminar flow and
Graphical Abstract
Scheme 1: Two-phase reaction of N,N-dialkylamine and sodium hypochlorite.
Figure 1: Calorimeter trace for the single phase reaction of morpholine (aq) and NaOCl (aq). Q Comp: compensa...
Figure 2: Meso-scale static mixer set-up for continuous N-chloramine formation. (a) Pumps, (b) reagent soluti...
Figure 3: Effect of static mixers on biphasic solution.
Figure 4: Progress of reaction for continuous formation of N-chloromorpholine. Morpholine (toluene) 0.9 M 1 m...
Figure 5: CSTR set-up for N-chloramine formation. (a) Syringe pump, (b) collection vessels, (c) reactor (50 m...
Figure 6: Interior of 50 mL CSTR.
Triple-channel microreactor for biphasic gas–liquid reactions: Photosensitized oxygenations
- Ram Awatar Maurya,
- Chan Pil Park and
- Dong-Pyo Kim
Beilstein J. Org. Chem. 2011, 7, 1158–1163, doi:10.3762/bjoc.7.134
- -volume ratio. Therefore, vigorous stirring, ultrasonic agitation, high pressure or supercritical conditions are typically applied to enhance mass transfer in batch reactors for gas–liquid biphasic reactions. Recently, we reported a dual-channel microreactor that dramatically improved the reaction rate of
Graphical Abstract
Figure 1: Schematic the for contacting modes of biphasic gas–liquid in (a) batch reactor, (b) dual-channel, a...
Figure 2: Optical image of the triple-channel microreactor (for demonstration purposes, the inner channel for...
Figure 3: Photosensitized oxygenation in the triple-channel microreactor.
Scheme 1: Photosensitized oxygenation of citronellol (a key step in the synthesis of rose oxide).
Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation
- Vladimir N. Boiko
Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88
- is a key reaction medium for the reaction of organic thiols with perfluoroalkyl iodides under UV irradiation. However, other solvents have been investigated including alcohols, acetone, acetonitrile, dioxane, THF, DMF, DMSO, HMPA and so on. Polar aprotic solvents emerge as the best. Biphasic
- reactions with water work well, particularly with diethyl ether and benzene (Table 4). Heterocyclic thiolates react more slowly with perfluoroalkyl iodides than thiophenoxides both in liquid ammonia and in organic solvents. Besides, in reactions with heterocyclic thiolates, as well as with thiophenoxides
Graphical Abstract
Figure 1: Examples of industrial fluorine-containing bio-active molecules.
Figure 2: CF3(S)- and CF3(O)-containing pharmacologically active compounds.
Figure 3: Hypotensive candidates with SRF and SO2RF groups – analogues of Losartan and Nifedipin.
Figure 4: The variety of the pharmacological activity of RFS-substituted compounds.
Figure 5: Recent examples of compounds containing RFS(O)n-groups [12-18].
Scheme 1: Fluorination of ArSCCl3 to corresponding ArSCF3 derivatives. For references see: a[38-43]; b[41,42]; c[43]; d[44]; e[38-43,45-47]; f[38-43,48,49]; g...
Scheme 2: Preparation of aryl pentafluoroethyl sulfides.
Scheme 3: Mild fluorination of the aryl SCF2Br derivatives.
Scheme 4: HF fluorinations of aryl α,α,β-trichloroisobutyl sulfide at various conditions.
Scheme 5: Monofluorination of α,α-dichloromethylene group.
Scheme 6: Electrophilic substitution of phenols with CF3SCl [69].
Scheme 7: Introduction of SCF3 groups into activated phenols [71-74].
Scheme 8: Preparation of tetrakis(SCF3)-4-methoxyphenol [72].
Scheme 9: The interactions of resorcinol and phloroglucinol derivatives with RFSCl.
Scheme 10: Reactions of anilines with CF3SCl.
Scheme 11: Trifluoromethylsulfanylation of anilines with electron-donating groups in the meta position [74].
Scheme 12: Reaction of benzene with CF3SCl/CF3SO3H [77].
Scheme 13: Reactions of trifluoromethyl sulfenyl chloride with aryl magnesium and -mercury substrates.
Scheme 14: Reactions of pyrroles with CF3SCl.
Scheme 15: Trifluoromethylsulfanylation of indole and indolizines.
Scheme 16: Reactions of N-methylpyrrole with CF3SCl [80,82].
Scheme 17: Reactions of furan, thiophene and selenophene with CF3SCl.
Scheme 18: Trifluoromethylsulfanylation of imidazole and thiazole derivatives [83].
Scheme 19: Trifluoromethylsulfanylation of pyridine requires initial hydride reduction.
Scheme 20: Introduction of additional RFS-groups into heterocyclic compounds in the presence of CF3SO3H.
Scheme 21: Introduction of additional RFS-groups into pyrroles [82,87].
Scheme 22: By-products in reactions of pyrroles with CF3SCl [82].
Scheme 23: Reaction of aromatic iodides with CuSCF3 [93,95].
Scheme 24: Reaction of aromatic iodides with RFZCu (Z = S, Se), RF = CF3, C6F5 [93,95,96].
Scheme 25: Side reactions during trifluoromethylsulfanylation of aromatic iodides with CF3SCu [98].
Scheme 26: Reactions with in situ generated CuSCF3.
Scheme 27: Perfluoroalkylthiolation of aryl iodides with bulky RFSCu [105].
Scheme 28: In situ formation and reaction of RFZCu with aryl iodides.
Figure 6: Examples of compounds obtained using in situ generated RFZCu methodology [94].
Scheme 29: Introduction of SCF3 group into aromatics via difluorocarbene.
Scheme 30: Tetrakis(dimethylamino)ethylene dication trifluoromethyl thiolate as a stable reagent for substitut...
Scheme 31: The use of CF2=S/CsF or (CF3S)2C=S/CsF for the introduction of CF3S groups into fluorinated heteroc...
Scheme 32: One-pot synthesis of ArSCF3 from ArX, CCl2=S and KF.
Scheme 33: Reaction of aromatics with CF3S− Kat+ [115].
Scheme 34: Reactions of activated aromatic chlorides with AgSCF3/KI.
Scheme 35: Comparative CuSCF3/KI and Hg(SCF3)2/KI reactions.
Scheme 36: Me3SnTeCF3 – a reagent for the introduction of the TeCF3 group.
Scheme 37: Sandmeyer reactions with CuSCF3.
Scheme 38: Reactions of perfluoroalkyl iodides with alkali and organolithium reagents.
Scheme 39: Perfluoroalkylation with preliminary breaking of the disulfide bond.
Scheme 40: Preparation of RFS-substituted anilines from dinitrodiphenyl disulfides.
Scheme 41: Photochemical trifluoromethylation of 2,4,6-trimercaptochlorobenzene [163].
Scheme 42: Putative process for the formation of B, C and D.
Scheme 43: Trifluoromethylation of 2-mercapto-4-hydroxy-6-trifluoromethylyrimidine [145].
Scheme 44: Deactivation of 2-mercapto-4-hydroxypyrimidines S-centered radicals.
Scheme 45: Perfluoroalkylation of thiolates with CF3Br under UV irradiation.
Scheme 46: Catalytic effect of methylviologen for RF• generation.
Scheme 47: SO2−• catalyzed trifluoromethylation.
Scheme 48: Electrochemical reduction of CF3Br in the presence of SO2 [199,200].
Scheme 49: Participation of SO2 in the oxidation of ArSCF3−•.
Scheme 50: Electron transfer cascade involving SO2 and MV.
Scheme 51: Four stages of the SRN1 mechanism for thiol perfluoroalkylation.
Scheme 52: A double role of MV in the catalysis of RFI reactions with aryl thiols.
Scheme 53: Photochemical reaction of pentafluoroiodobenzene with trifluoromethyl disulfide.
Scheme 54: N- Trifluoromethyl-N-nitrosobenzene sulfonamide – a source of CF3• radicals [212,213].
Scheme 55: Radical trifluoromethylation of organic disulfides with ArSO2N=NCF3.
Scheme 56: Barton’s S-perfluoroalkylation reactions [216].
Scheme 57: Decarboxylation of thiohydroxamic esters in the presence of C6F13I.
Scheme 58: Reactions of thioesters of trifluoroacetic and trifluoromethanesulfonic acids in the presence of ar...
Scheme 59: Perfluoroalkylation of polychloropyridine thiols with xenon perfluorocarboxylates or XeF2 [222,223].
Scheme 60: Interaction of Xe(OCORF)2 with nitroaryl disulfide [227].
Scheme 61: Bi(CF3)3/Cu(OCOCH3)2 trifluoromethylation of thiophenolate [230].
Scheme 62: Reaction of fluorinated carbanions with aryl sulfenyl chlorides.
Scheme 63: Reaction of methyl perfluoromethacrylate with PhSCl in the presence of fluoride.
Scheme 64: Reactions of ArSCN with potassium and magnesium perfluorocarbanions [237].
Scheme 65: Reactions of RFI with TDAE and organic disulfides [239,240].
Scheme 66: Decarboxylation of perfluorocarboxylates in the presence of disulfides [245].
Scheme 67: Organization of a stable form of “CF3−” anion in the DMF.
Scheme 68: Silylated amines in the presence of fluoride can deprotonate fluoroform for reaction with disulfide...
Figure 7: Other examples of aminomethanols [264].
Scheme 69: Trifluoromethylation of diphenyl disulfide with PhSO2CF3/t-BuOK.
Scheme 70: Amides of trifluoromethane sulfinic acid are sources of CF3− anion.
Scheme 71: Trifluoromethylation of various thiols using “hyper-valent” iodine (III) reagent [279].
Scheme 72: Trifluoromethylation of p-nitrothiophenolate with diaryl CF3 sulfonium salts [280].
Scheme 73: Trifluoromethyl transfer from dibenzo (CF3)S-, (CF3)Se- and (CF3)Te-phenium salts to thiolates [283].
Scheme 74: Multi-stage paths for synthesis of dibenzo-CF3-thiophenium salts [61].
