Extraction and determination of crown ethers from water samples using a membrane disk and gas chromatography

A method for rapid extraction and determination of some crown ethers in aqueous matrices using octadecyl-bonded silica membrane disks and gas chromatography is presented. Extraction efficiency and the influence of vacuum pressure. pH, and type and least amount of eluting solvent used to extract the crown ethers from the membrane disks were evaluated. Extraction efficiencies > 95% were obtained for benzo-15-crown-5, benzo-18-crown-6 and dicyclohexyl-18-crown-6 using 5 ml of acetonitrile as eluting solvent. The limit of detection of the proposed method for the determination of the crown ethers is reported.     

冠醚共缩聚物的合成与性能

双冠醚化合物对某些金属离子比单冠醚具有更好的络合性能和选择性,它们合成、应用研究越来越受到人们的重视,本工作采用2,6-二羟甲基对甲氧基苯酚为缩合剂与芳香族冠醚缩聚,得到一系列具有双冠醚结构特征的新酚醛型聚苯并冠醚(简称聚冠醚),聚冠醚合成容易,并呈现了比相应单冠醚更优越的络合萃取能力和富集效率。     

Preparation and study of two polysiloxanes with pendant hand-basket type calixarene stationary phases for capillary gas chromatography

In this study two novel pendant hand-basket type calixarene gas chromatography stationary phases were prepared by hydrosilylation of ω-undecenyloxymethyl dimethyl calix[4]-15C5 and ω-undecenyloxymethyl dimethyl calix[4]-18C6 with dichloromethane followed by condensation reaction with silanol-terminated polydimethylsiloxane. Important stationary phase properties of these two novel stationary phases such as column efficiency, polarity, and selectivity were examined and compared with those of ω-undecyloxymethyl-18-crown-6, 2,3-benzo-9-propyloxymethyl-15-crown-5 and 2,3-benzo-11-propyloxymethyl-18-crown-6. Excellent thermostability from 60 to 330°C with onset bleeding temperatures at 308°C have been found. The mechanism of specific selectivity for position isomers based on the calix[4]crown ether ring, the molecular size of the solute and its shape are discussed.     

Nitration of Benzo Crown Ethers with Potassium Nitrate in Polyphosphoric Acid

A general method for the nitration of benzo crown ethers with potassium nitrate in polyphosphoric acid has been developed. Mono- and dinitro derivatives of benzo-12-crown-4, benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-24-crown-8 have been prepared. The role of complex formation in the regioselective tendency for the nitration of dibenzo-18-crown-6 has been demonstrated.     

酚醛冠醚共缩聚物的合成与性能

用2,6-二羟甲基-4-苯基苯酚分别与二苯并-18-冠-6(2B18C6)、二苯并-24-冠-8(2B24C8)、二苯并-30冠-10(2B30C10)、苯并-15-冠-5(B15C5)、苯并-18-冠-6(B18C6)缩聚合成了五种酚醛型冠醚共聚物。我们用聚冠醚的氯仿溶液萃取苦味酸碱金属盐水溶液,研究了它们对金属离子的络合性能。结果表明,聚冠醚(PB15C5)和(PB18C6)的萃取能力和选择性显著优于相应的单冠醚。     

Effect of rigid fragments in the macrocycle on the adaptation of crown ethers to alkali-metal ions

Complexation selectivity curves were obtained by theoretical conformational analysis and penalty functions in terms of the conformational factors in the following crown ethers: 15-crown-5; benzo-15-crown-5: 18-crown-6; benzo-18-crown-6; dibenzo-18-crown-6; cyclohexano-18-crown-6. In the last case the effect of cis—trans isomerism in the bridging bonds on the selectivity of complexation with the ligand was investigated. Analysis of the selectivity curves shows that the introduction of aromatic fragments into the macrocycle reduces its adaptive capabilities. The complexation selectivity of the ligands from the selectivity curves is compared with the experimental stability series of the crown ether complexes with alkali metals.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 3, pp. 355–360, May–June, 1990.     

Complexes of sodium and lithium borohydrides with macrocyclic polyethers

A method for the synthesis of complexes of sodium and lithium borohydrides with crown ethers is proposed. The complexes of sodium borohydride with benzo-15-crown-5, 4′-aminobenzo-15-crown-5, dibenzo-18-crown-6, and diaza-18-crown-6 and the complexes of lithium borohydride with benzo-15-crown-5 and dibenzo-18-crown-6 are synthesized. These complexes can be used for the preparation of hydrogen in their reactions with methanol. The complex formation does not affect the purity of hydrogen formed.     

Perfluoroalkylation of benzo crown ethers with sodium perfluoroalkanesulfinates in the presence of oxidant

Using Ce(SO4)2 or Mn(OAc)3 as oxidant, dibenzo crown ethers such as dibenzo-18-crown-6 (1) and dibenzo-24-crown-8 (5) and benzo-12-crown-4 (7) reacted smoothly with sodium perfluoroalkanesulfinates (2a-2e) to give the corresponding perfluoroalkylated products (3,4,6,7) in good yields with two isomers obtained in the case of dibenzo crown ethers. This provides a facile synthesis of perfluoroalkyl-containing crown ethers.     

Quantitative evaluation of interactions of organic compounds with 18-crown ethers and β-cyclodextrin as components of stationary phases for gas chromatography

Individual stationary phases for gas chromatography based on 18-crown-6 and dibenzo-18-crown-6 (10% on Inerton N AW) and a stationary phase of a mixed composition (polyethylene glycol PEG-3000 and cyclodextrin β-CD) are prepared. These stationary phases are characterized using the McReynolds system and the Abraham solvation parameter model. It is shown that the solvation parameter model can be used to estimate the polarity of gas-chromatographic stationary phases based on the differences in intermolecular interactions between the studied gas-chromatographic stationary phase and the analyte during the separation process. Binary gas-chromatographic stationary phases based on glycerin and β-cyclodextrin with different concentrations of the macrocycle are studied at temperatures of 60 and 80°C, and the complexation constants of β-cyclodextrin with organic substances of various classes are calculated.     

冠醚共缩聚物的合成与性能（Ⅱ）

采用２，６－二羟甲基苯酚类化合物分别与单苯并冠醚（Ｂ１５ＣＳ、Ｂ１８Ｃ６）和Ｍ苯并冠醚（２Ｂ１８Ｃ６、２Ｂ２４Ｃ８、２Ｂ３０Ｃ１０）在酸催化下缩聚，合成了两个系列冠醚共缩聚物．这些聚合物Ｍ＝１２００—４５００，可溶于氯仿等溶剂，萃取性能和络合选择性均有所提高．作为树脂使用，动态吸附容量为０．０５—０．１５ｍｍｏｌ／ｇ，并有较好的色谱特性．     

Extraction of tetrafluoroborate with crown ethers and its application to silicate rock analysis

Summary The extraction behaviour of tetrafluoroborate with crown ethers was studied. A high distribution ratio of tetrafluoroborate is obtained by extraction with dicyclohexano-18-crown-6 (DC18C6) in an organic solvent of high dielectric constant from potassium fluoride solution. The molar ratios of crown ether to KBF₄ in the extracted species are probably 1:1 for DC18C6, dibenzo-18-crown-6 and 18-crown-6, and 2:1 for benzo-15-crown-5 and 15-crown-5. The flow-injection extraction-spectrophotometric determination of tetrafluoroborate with Brilliant Green was worked out. Many rock reference samples were analyzed for boron (1–150 ppm).     

冠醚共缩聚物的合成与性能（Ⅱ）

采用２，６－二羟甲基苯酚类化合物分别与单苯并冠醚（Ｂ１５Ｃ５、Ｂ１８Ｃ６）和二苯并冠醚（２Ｂ１８Ｃ６、２Ｂ２４Ｃ８、２Ｂ３０Ｃ１０）在酸催化下缩聚，合成了不同两个系列冠醚共缩聚物，这些聚合物Ｍ＝１２００－４５００，可溶于氯仿等溶剂，萃取性能和络合选择性均有所提高。作为树脂使用，动态吸附容量为０．０５－０．１５ｍｍｏｌ／ｇ，并有较好的色谱特性。     

双冠醚的研究(Ⅶ)——Schiff碱型和仲胺型双(苯并-18-冠-6)的合成

4′-氨基苯并-18-冠-6分别与间-硝基苯甲醛、对-硝基苯甲醛、间-苯二甲醛及其取代物和对-苯二甲醛缩合制得6种新的Schiff碱型单冠醚和双冠醚。4′-甲酰基苯并-18-冠-6分别与4′-氨基苯并-15-冠-5、4′-氨基苯并-18-冠-6作用制得2个醚环大小相同和不同的Schiff碱型双(苯并冠醚)。这些双冠醚经硼氢化钠还原得到相应的6种新的仲按型双冠醚。     

Crown ether molecular complexes with urea and thiourea

Crystalline complexes of urea and thiourea with crown ethers, have been prepared, viz., 18-crown-6 (18C6), benzo-18-crown-6 (B18C6), dibenzo-18-crown-6 (DB18C6), dicyclohexano-18-crown-6 (DC 18C6) and dibenzo-24-crown-8 (DB24C8). While the complexes of the large ring size crown ether, DB24C8, have high ether to (thio)urea ratios, the stoichiometry of the others lies between one molecule of crown ether and from one to six molecules of (thio)urea. An IR spectral study of the urea and thiourea complexes showed that the behavior of thiourea in these complexes is clearly different from that of urea, indicating the role of sulphur in the interaction of thiourea with crown ethers. The urea and thiourea complexes were classified according to their stoichiometries and their IR spectral behavior into three classes for which credible structures were proposed.     

Reaktionen von Kaliumiodomercurat(II) mit Kronenethern und Kryptanden: Kristallstrukturen von Bis[di(benzo-15-krone-5)kalium]-, Di[(benzo-18-krone-6)kalium]-, Di[(cryptand 221)kalium]und Di[(cryptand 222)kalium]-hexaiododimercurat(II)

Reactions of Potassium Iodomercurate(II) with Crown Ethers and Cryptands: Crystal Structures of Bis[di(benzo-15-crown-5)potassium]-, Di[(benzo-18-crown-6)potassium]-, Di[(cryptand 221)potassium]-, and Di[(cryptand 222)potassium] Hexaiododimercurate(II) The reactions of potassium iodomercurate(II) with the crown ethers benzo-15-crown-5, and benzo-18-crown-6, resp. as well as with the cryptands 221 and 222 were investigated. In all cases only the potassium ion was complexed. As anions only hexaiododimercurate(II) ions were formed but no higher oligomers. If the complexed potassium ion is not completely shielded by the ligand, further coordination by terminal iodine atoms of the mercurate anions takes place, leading to the formation of dimers or chains.     

Determination of the purity,melting point and heat of melting of cyclic polyethers

Conclusions Differential scanning calorimeter was used to determine the thermal stability, purity, melting point, and heat of melting of benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-24-crown-8. These crown ethers have relatively high heats of melting.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 691–692, March, 1986.     

双酚A 型聚冠醚的合成与性能

由于聚冠醚具有选择性配位阳离子的性能,同时具有毒性低、易于回收等优点,所以它们在相转移催化、金属分离浓缩等方面有重要的应用前景。我们曾报道用2,6-二(羟     

Dibenzotetraaza crown ethers: a new family of crown ethers based on o-phenylenediamine

Dibenzotetraaza (DBTA) crown ethers possess two o-phenylenediamine moieties. They are homologues of dibenzo crown ether phase-transfer catalysts and were prepared from the condensation of benzimidazoles with oligo(ethyleneglycol) dichlorides and oligo(ethyleneglycol) ditosylates. Compounds with ring sizes ranging from 18-crown-6 to 42-crown-14 were prepared. In addition, various altered benzimidizoles were used to produce DBTA crown ethers with modified substituents and ether bridges, as well as benzimidazolidine crown ethers. The synthetic approach presented here proved to be a convenient route to a new family of crown ethers with overall yields of up to 48% based on the benzimidazole. Yields for the ring-closing step were generally high, ranging from 51% to 94%, without the need for high-dilution conditions. Reaction of the DBTA crown ethers with alkyl and benzyl halides was found to be a facile way to obtain the corresponding tetra(N-organyl) compounds. Picrate extraction studies were carried out to determine phase-transfer catalytic capabilities. Extraction efficiencies for alkali-metal ions were lower than those for dibenzo-18-crown-6. Efficiencies were higher for other metal ions, with some selectivity for Pb(2+). Tetra(N-methyl) DBTA-18-crown-6 generally exhibited higher extraction efficiencies than its N-H analogue, but the selectivity was lower.     

Formation Constants of Complexes of Monovalent Cations with Benzocrown Ethers in Nitromethane

The complexation reactions between the macrocyclic polyethers dibenzo-18-crown-6, benzo-18-crown-6, benzo-15-crown-5 and polyethers bearing a stilbene unit with alkali metal and silver cations have been studied conductometrically in nitromethane. The formation constants of 1 : 1 and 1 : 2 (metal : ligand) complexes were determined and found to decrease with increasing cation diameter. The stability of the stilbene crown – metal cation complexes is lower than for complexes of other investigated crown ethers with analogous cations. There seem to be some effects of double bond-silver ion interactions.     

双苯甲酰胺冠醚固定相的合成及毛细管柱气相色谱性能的研究

合成了一种新型的双苯甲酰胺冠醚固定相:(1S,2S)-1-(对苯甲酰胺基)苯基-2-苯甲酰胺基-16-冠-5,其结构经红外光谱、核磁共振、质谱及元素分析数据证实。考察了这种固定相的柱效、热稳定性、极性及选择性等色谱特性。该类固定相对极性位置异构体分离效果良好。由于冠醚上引入苯甲酰胺取代基,因而对苯胺类及不经衍生化的碱性化合物能特殊选择性地分离。