17455-13-9Relevant articles and documents
Ping-Lin et al.
, p. 504 (1978)
N,N'-BIS(SUBSTITUTED)-4,13-DIAZA-18-CROWN-6 DERIVATIVES HAVING PI-DONOR-GROUP-SIDEARMS: CORRELATION OF THERMODINAMICS AND SOLID STATE STRUCTURES
Arnold, Kristin A.,Viscariello, Anthony M.,Kim, MinSook,Gandour, Richard D.,Fronczek, Frank R.,Gokel, George W.
, p. 3025 - 3028 (1988)
Solution thermodynamic data and solid state structure information are used to show that a series of N,N'-bis(substituted)-4,13-diaza-18-crown-6 (BiBLE) derivatives which lack oxygen or nitrogen donor groups in the sidearms do not utilize the sidearms for binding but show considerable variation in their binding constants.
Kawamura et al.
, p. 535 (1979)
Interactions of a Diarylmagnesium Compound with Cryptands, and Crown Ethers: Formation of Ar3Mg-, ArMg(cryptand)+, and Threaded Ar2Mg(crown ether)
Richey, Jr., Herman G.,Kushlan, Diana M.
, p. 2510 - 2512 (1987)
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Dale,Daasvatu
, p. 295 (1976)
Facile and rapid synthesis of some crown ethers under microwave irradiation
Ziafati, Ahmad,Sabzevari, Omolbanin,Heravi, Majid M.
, p. 803 - 807 (2006)
A series of crown ethers were synthesized from the reaction of 1,8-dichloro-3,6-dioxaoctane with the appropriate hydroxy compound under microwave irradiation in short times and high yields. Copyright Taylor & Francis Group, LLC.
Lithium-7 Nuclear Magnetic Resonance and Calorimetric Study of Lithium Crown Complexes in Various Solvents
Smetana, Alfred J.,Popov, Alexander I.
, p. 183 - 196 (1980)
Lithium-7 NMR studies have been carried out on lithium ion complexes with crown ethers 12C4, 15C5, and 18C6 in water and in several nonaqueous solvents.In all cases the exchange between the free and complexed lithium ion was fast on the NMR time scale, and a single, population average, resonance was observed.Both 1:1 and 2:1 (sandwich) complexes were observed between lithium ion and 12C4 in nitromethane solution.The stability of the complexes varied very significantly with the solvent.With the exception of pyridine, the stability varies inversely with the Gutmann donor numbers of the solvent.In general, the stability order of the complexes was found to be 15C5*Li+ > 12C4*Li+ >18C6*Li+.Calorimetric studies on thse complexes show that, in most cases, the complex are both enthalpy and entropy stabilized.
TEMPLATE EFFECTS. 7. LARGE UNSUBSTITUTED CROWN ETHERS FROM POLYETHYLENE GLYCOLS: FORMATION, ANALYSIS, AND PURIFICATION
Vitali, Chiara Antonini,Masci, Bernardo
, p. 2201 - 2212 (1989)
Through the reaction of polyethylene glycols with tosyl chloride and heterogeneous KOH in dioxane not only coronands from crown-4 to crown-8 can be obtained but also larger homologues.A systematic investigation has shown that: i) crown-9 and crown-10 can be formed from nona- and deca-ethylene glycol, respectively, and isolated in pure form; ii) the whole series of polyethylene glycols from tri- to deca-ethylene glycol yields not only the corresponding crown ethers but also higher cyclooligomers that can be analyzed up to about crown-20 by glc: in particular crown-12 and crown-16 were obtained from tetraethylene glycol and purified by column chromatography on cellulose; iii) the reaction, as applied to commercial mixtures of polyethylene glycols (from PEG 200 to PEG 1000), gives fairly high yields of crown ethers also in the region of large ring sizes.The contribution of the template effect of K(+) ion and the cyclooligomerization reactions for the various ring sizes are discussed.
Synthesis and Characterization of Large (30-60-Membered) Aliphatic Crown Ethers
Gibson, Harry W.,Bheda, Mukesh C.,Engen, Paul,Shen, Ya Xi,Sze, Jean,et al.
, p. 2186 - 2196 (1994)
We report a new synthetic approach to large (30-72 membered) crown ethers based on isolation of the small and large cyclic polyethers made by combination of 1 mol or 2 mol each, respectively, of oligo(ethylene glycol)s and oligo(ethylene glycol) ditosylates.The advantages of this approach are the use of readily available glycols as starting materials and the ability to optimize the procedure for selective production of either macrocycle, producing yields superior or comparable to previous methods.At higher reaction temperatures the large crown ether is preferentially formed.This approach has been used to produce the crown ethers on 100-g scales.Purification was achieved by a combination of filtration through silica gel, treatment with a polymeric acid chloride, and recrystallization techniques, avoiding standard column chromatography.The pure crown ethers, 60-crown-20, 48-crown-16, 42-crown-14, 36-crown-12, and 30-crown-10, were characterized by melting points, 1H- and 13C-NMR, elemental analysis, and/or MS, GC-MS, and TGA-MS.Melting points were as much as 26 deg C higher than previously reported for these crown ethers.All the aliphatic crown ethers larger than 18-crown-6 decompose upon heating in air at ca. 200 deg C.
The Reduction of Crown Lactones to Crown Ethers
Ager, David J.,Sutherland, O.
, p. 248 - 249 (1982)
Crown lactones may be reduced to crown ethers using lithium aluminium hydride.
Temperature-dependent IR spectroscopic and structural study of 18-crown-6 chelating ligand in the complexation with sodium surfactant salts and potassium picrate
Mihelj, Tea,Toma?i?, Vlasta,Bili?kov, Nikola,Liu, Feng
, p. 12 - 20 (2014)
18-crown-6 ether (18C6) complexes with the following anionic surfactants: sodium n-dodecylsulfate (18C6-NaDS), sodium 4-(1-pentylheptyl)benzenesulfonate (18C6-NaDBS); and potassium picrate (18C6-KP) were synthesized and studied in terms of their thermal and structural properties. Physico-chemical properties of new solid 1:1 coordination complexes were characterized by infrared (IR) spectroscopy, thermogravimetry and differential thermal analysis, differential scanning calorimetry, X-ray diffraction and microscopic observations. The strength of coordination between Na+ and oxygen atoms of 18C6 ligand does not depend on anionic part of the surfactant, as established by thermodynamical parameters obtained by temperature-dependent IR spectroscopy. Each of these complexes exhibit different kinds of endothermic transitions in heating scan. Diffraction maxima obtained by SAXS and WAXS, refer the behavior of the compounds 18C6-NaDS and 18C6-NaDBS as smectic liquid crystalline. Distortion of 18C6-NaDS and 18C6-KP complexes occurs in two steps. Temperature of the decomplexation of solid crystal complex 18C6-KP is considerably higher than of mesophase complexes, 18C6-NaDS, and 18C6-NaDBS. The structural and liquid crystalline properties of novel 18-crown-ether complexes are function of anionic molecule geometry, type of chosen cation (Na+, K +), as well as architecture of self-organized aggregates. A good combination of crown ether unit and amphiphile may provide a possibility for preparing new functionalized materials, opening the research field of ion complexation and of host-guest type behavior.
Synthesis and molecular structures of novel isopropyl-substituted oligosilanes
Tanaka, Ryoji,Unno, Masafumi,Matsumoto, Hideyuki
, p. 595 - 596 (1999)
The cyclotetrasilane [(i-Pr)2Si]4 reacts with K in benzene in the presence of 18-crown-6 to give the 1,4-dipotassio compound K[(i-Pr)2Si]4K (1). The reaction of 1 with (i-Pr)2SiCl2 and Me3SiCl leads to the formation of the sterically crowded oligosilanes, [(i-Pr)2Si]5 (2) and Me3Si[(i-Pr)2Si]4SiMe3 (3), respectively. The molecular structures of the resulting oligosilanes, 2 and 3, display some unusual features.
Preparation method of 18-crown-6
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Paragraph 0022-0045, (2020/02/17)
The invention discloses a preparation method of 18-crown-6. The method comprises the following steps of: under the stirring condition, adding a protonated solvent into a reaction flask filled with triethylene glycol and potassium hydroxide; then dropwise adding paratoluensulfonyl chloride into the reaction flask, controlling a reaction temperature to be within a range of 30 to 80 DEG C and controlling reaction time to be within a range of 2 to 6h; adding a separating agent into solution obtained after reaction for separating a potassium p-toluenesulfonate by-product, controlling a reaction temperature to be within a range of 70 to 100 DEG C, and controlling reaction time to be within a range of 3 to 6h; carrying out filtering, concentration and vacuum distillation on the obtained solution,washing distillate with distilled water, carrying out standing layering, settling lower solution by centrifugal separation, and drying sediments, so as to obtain the 18-crown-6. The preparation method disclosed by the invention is simple; when a high reaction rate and a high reactant conversion rate are ensured, the subsequent separation operation is also simplified, subsequent processing links are reduced, and purity of the final product is ensured.
A 18 - crown ether -6 synthetic method (by machine translation)
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Paragraph 0021; 0023; 0024; 0025, (2018/09/11)
The invention discloses a 18 - crown ether - 6 synthesis approach, the method is: in industrial microwave reactor is sequentially added in 1 to [...] alcohol methyl benzene sulfonic acid, 1.01 - 1.5 [...] of dihydric alcohol, 2 - 20 mol of alkali, 0 - 10 molar parts of solvent, for 0 °C -40 °C reaction under 10 minutes to 5 hours, after the reaction, and then after removing salt separation, extraction, evaporate the solvent, the crude product is distilled under reduced pressure, get the 18 - crown - 6. The technique has the room temperature, the reaction time of the ultra-short, and labor, high yield, water can be adopted as the solvent characteristics, is suitable for industrial production, can greatly reduce cost, energy-saving, and improves productivity, there is a significant economic benefits. (by machine translation)
