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Search for "emulsion" in Full Text gives 46 result(s) in Beilstein Journal of Organic Chemistry.
Cage-like microstructures via sequential Ugi reactions in aqueous emulsions
Beilstein J. Org. Chem. 2024, 20, 2078–2083, doi:10.3762/bjoc.20.179
- the formation of a double Pickering emulsion using a microfluidic technique. Solidification of this structure and removal of the template resulted in the formation of nonspherical capsules with large openings [13]. The use of a polymer matrix that can swell in an organic solvent made it possible to
- obtain colloidosomes covered with fissures of a controlled size [10]. A simpler method recently proposed involves the self-assembly of starch granules on the surface of emulsion droplets. However, this approach did not allow the pore size to be controlled [14]. Thus, the currently available methods for
- obtaining cage-like structures are characterized by technical complexity, a multi-stage nature, and low yield of target structures. To develop a one-step method for the synthesis of cage-like structures, it is necessary to control the deposition process of colloidal particles on the surface of emulsion
Synthesis and properties of 6-alkynyl-5-aryluracils
Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80
- mmol; 3 mL) was added and the emulsion was stirred for 10 min at room temperature. The corresponding arylacetylene (p-tolylacetylene, 2.20 mmol, 0.28 mL) was slowly added dropwise to the reaction mixture and stirred for 6 hours at room temperature. The reaction was monitored by TLC until the reaction
Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors
Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46
- aqueous suspension or emulsion, with the addition of 0.5% of an additive at an application rate of 600 L of water/ha (converted). Following treatment, the pots were placed in a greenhouse and kept under optimum growth conditions for the test plants. The test plants were placed in the greenhouse for ca
Unprecedented synthesis of a 14-membered hexaazamacrocycle
Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126
- -1,2,4-triazol-4-amine (10): To an emulsion of N2H4·H2O (0.301 g, 6.01 mmol) in 1,4-dioxane (2 mL) was added TsOH·H2O (0.019 g, 0.10 mmol) and the mixture was stirred until solids completely dissolved. Then, pyrazolopyrimidine 8 (0.337 g, 2.05 mmol) and 1,4-dioxane (2 mL) were added, the reaction mixture
Radical chemistry in polymer science: an overview and recent advances
Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116
- , solution, emulsion, and suspension; and (iv) inexpensive and facile set-ups compared to other polymerization techniques [20]. There are four common industrial methods of radical polymerization [2] as shown in Table 1. The only components of a bulk polymerization mixture are monomers, the initiator, and
- . Emulsion polymerization is also a widely-used method in radical polymerization. It is applied to produce several commercially important polymers such as acrylic rubber, nitrile rubber, and polytetrafluoroethylene (PTFE). Polymerization happens in latex or colloid particles that are formed under the action
- water phase and oil phase into an emulsion phase. The simultaneous presence of a hydrophobic head and a hydrophilic tail on emulsifiers provides the ability to combine water and oil phase into an emulsion. In emulsion polymerization, high molecular weights can be achieved at fast polymerization rates
Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis
Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30
- % [17]. Other complexes between CDs and various vegetable oils have been obtained and characterized. Soybean oil was combined with α-CD for obtaining a stable dry emulsion, which implied the partial molecular encapsulation of the soybean oil triglycerides. This emulsion was prepared in order to modulate
Preparation of β-cyclodextrin/polysaccharide foams using saponin
Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7
- the emulsion production needs to be followed quickly by the freezing of the foam, otherwise a continuous liquid phase could be formed prior to the lyophilization process. The two chitosan solutions, with or without cyclodextrin, produce foams with similar stabilities. On the other hand, the presence
- than for the one obtained by the foam path. The latter possesses also a higher specific area (Supporting Information File 1, Figure S2). On the other hand, the polysaccharide matrices (see Figure 4 for chitosan matrices) do no create the same type of pores; the successful emulsion process keeps its
- . The second process (45spFoam*) consists of introducing 20 mL of the stock solution into a large crystallizer, where the liquid height reaches around 1 cm. The liquid is stirred during 5 min at high speed to make an air/water emulsion. The resulting foam is quickly frozen at −40 °C, lyophilized
Menadione: a platform and a target to valuable compounds synthesis
Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43
- ). The studies showed that the emulsion, prepared by sonication, of an equimolar mixture of lithium perfluorooctane sulfonate (LiFOS) and perfluorohexane (PFH) in aqueous medium resulted in a significant increase of the reaction rate, when compared to other reaction conditions [109]. As an example, using
Synthesis and late stage modifications of Cyl derivatives
Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19
- dioxane gave the crude ammonium salt, which was subjected to biphasic ring closure; the hydrochloride salt was added dropwise to a stirred emulsion of saturated NaHCO3 solution in chloroform [55]. Macrocycle 11 was obtained in acceptable yield as a diastereomeric mixture (dr 87:13), but the diastereomers
Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing
Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171
Easy access to a carbohydrate-based template for stimuli-responsive surfactants
Beilstein J. Org. Chem. 2020, 16, 2788–2794, doi:10.3762/bjoc.16.229
- control, only containing the solvent mixture (Figure 3). All three vials were agitated for a few seconds in order to mix the layers generating an emulsion. The stability of the emulsion is a measure of how well compound 19 acts as an emulsifier. In Figure 3b it can be seen that already after agitation
- , the control vial (vial 1) and vial 2 show very unstable emulsions while the emulsion formed in vial 3 was stable even after 50 seconds (Figure 3c). This experiment indicates that compound 19 only works as an emulsifier in the presence of Zn2+ ions thereby confirming that the compound displays
Heterogeneous photocatalysis in flow chemical reactors
Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125
Architecture and synthesis of P,N-heterocyclic phosphine ligands
Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35
- the red phosphorus with 2-bromopyridine in potassium hydroxide/dimethyl sulfoxide emulsion, pyridylphosphine was obtained in moderate yields. Traces of phosphine oxide were present as evidenced by the observation of two phosphorus peaks in the 15P NMR spectrum. An optimized method via Grignard
Mono- and bithiophene-substituted diarylethene photoswitches with emissive open or closed forms
Beilstein J. Org. Chem. 2019, 15, 2344–2354, doi:10.3762/bjoc.15.227
- atmosphere, an emulsion of the starting compounds, Pd2(dba)3, P(Cy)3 stock solution, and aqueous K2CO3 in THF (see Supporting Information File 1 for details). Saponification of methyl ester groups in tetraester SyTh2 leading to tetracarboxylic acid SyTh2-H. Optical properties of the photochromic DAEs (in
Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis
Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118
- out with a concentrated basic solution. The use of a 1 M NaOH (5 mL) solution requires two washes of 10 min each but at the end of the reaction an emulsion may appear. In order to avoid this problem an excess of 0.1 M NaOH solution was used. Polymers were isolated by precipitation in petroleum ether
Aqueous olefin metathesis: recent developments and applications
Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39
- -II (77% conversion in MeOH/H2O 1:3 and 29% conversion in MeOH/H2O 3:1). The drastic loss of activity can be traced back to the better activity of G-II under aqueous-emulsion conditions and the poor solubility of G-II in MeOH. These results suggest how important the role of the hydrophobic effect is
- on the catalytic activity of the reaction. In fact, catalyst and substrate are encapsulated into emulsion droplets formed in the reaction media above the aqueous layer, making the reaction proceed “on water” [21][22]. The introduction of amphiphilic molecules for aqueous micellar catalysis allows
Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis
Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265
- , and Ru [1]. Initially, these complexes were considered to be sensitive towards air and moisture. Nevertheless, adding Ru, Os and Ir salts to an aqueous solution or emulsion of a norbornene derivative led to ring-opening metathesis polymerization to give the corresponding polymer [5][6]. Through
β-Hydroxy sulfides and their syntheses
Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143
- , the added advantage of the protocol is that when LiNTf2 is used instead of Lewis acids, the work-up is easier as no vexatious emulsion was formed. However, the need for 0.5 equiv of the promoter and the sluggishness (20 h) of the reaction make the method less favorable when compared to other Lewis
Nanoreactors for green catalysis
Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61
- ) was encapsulated in the lumen of the polymersomes or in the Pickering emulsion water droplet. The esterification reaction of 1-hexanol and hexanoic acid was used to evaluate the catalytic performance of the CalB-loaded Pickering emulsions. Higher enzymatic activity was observed when CalB was
- representation of a Pickering emulsion with the enzyme in the water phase (i), or with the enzyme inside the polymersome lumen (ii). 3b) Chart of the specific activities of CalB dissolved in the water phase of the polymersome Pickering emulsion (left), CalB in a biphasic water/toluene system (middle,) and CalB
- encapsulated in the lumen of the polymersome Pickering emulsion (right). Adapted with permission from [79]. Cross-linked polymersomes with Cu(OTf)2 catalyst. Reprinted with permission from [15]. Schematic representation of enzymatic polymerization in polymersomes. (A) CALB in the aqueous compartment (B) CALB
Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry
Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52
- droplets [25]. So-called Pickering emulsions, however, are stabilised solely by solid colloidal particles which can adsorb to droplet interfaces forming a protective layer endowing the emulsion with extremely high stability to coalescence [26]. Examples of suitable particles include silica, alumina, metals
- interfacial area for reaction, the ultrastability of emulsion drops during reaction and easy recovery of the catalyst particles and products as emulsions may be rendered unstable subsequently. A mini-review of the area of Pickering emulsion interfacial catalysis appeared in 2015 [30]. In this work an outlook
- reduction of catalyst particles As mentioned before, the as synthesised catalyst particles have particle diameters in the range of 10–100 µm. Since the stabilisation of micron-sized Pickering emulsion droplets requires particle sizes <1 μm, a decrease of particle size was necessary. For that purpose, a
A concise flow synthesis of indole-3-carboxylic ester and its derivatisation to an auxin mimic
Beilstein J. Org. Chem. 2017, 13, 2549–2560, doi:10.3762/bjoc.13.251
- positioned run-off. At flow rates of 0.5–1.2 mL/min emanating from the main reactor this unit performed reliably giving excellent quenching and separation. However, at higher flow rates issues were encountered with incomplete partitioning (some emulsion formation) of the biphasic mixture resulting in the
A recursive microfluidic platform to explore the emergence of chemical evolution
Beilstein J. Org. Chem. 2017, 13, 1702–1709, doi:10.3762/bjoc.13.164
- , a few recent examples in the literature report the utilisation of pico- and nanolitre microfluidic water-in-oil droplets and liposomes as artificial cell analogues [14][15]. Aqueous, single emulsion microdroplets can be produced at kilohertz frequencies, and provide compartmentalisation on a similar
- evolution in droplets Here, we propose a system for facilitating chemical evolution in populations of co-incubating aqueous, single emulsion microfluidic droplets. Each microdroplet can be considered an autonomous microreactor, loaded with a self-propagating chemical reaction network. However, it has been
Diels–Alder reactions of myrcene using intensified continuous-flow reactors
Beilstein J. Org. Chem. 2017, 13, 120–126, doi:10.3762/bjoc.13.15
- Supporting Information File 64: Analysis procedures, calculation of k-values, reactor performance profiles, reactor fouling, emulsion stabilizing properties, copies of 1H and 13C NMR and of GC-FID spectra. Acknowledgements The authors thank Charlotte Wiles from Chemtrix BV for helpful discussions and
Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin
Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20
- linolenic acid (MLN) in emulsion. Anthocyanins (as natural extracts) were effective at increasing the stability of salmon oil when incorporated in a hydroxypropyl methylcellulose matrix for obtaining fish oil packaging films [21]. The addition of BHT, propyl gallate and citric acid to the herring byproducts
Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation
Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7
- due to host–guest complexation as observed by 19F NMR spectroscopy [47]. Subsequently, Islam et al. observed the host–guest complexation of the linear alkyl substituents n-C8H17, n-C16H33 and n-C20H41 of hydrophobically substituted alkali-soluble emulsion (HASE) polymers by methylated β-CD using gel
- surfactants based on poly(ethylene glycol) to recover the hydrophobic associations in hydrophobically substituted alkali-soluble emulsion (HASE) polymers complexed by α-CD and β-CD [41]. (It should be noted that association occurs between hydrophobically substituted polymers in aqueous solution and that this
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