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991.
The Schiff base‐containing pendant monoaza crown ether HL1, HL2, HL3 and HL4 have been synthesized by condensation of salicylaldehyde with N‐(4‐aminoaryl) monoaza crown ethers, which were prepared conveniently from 4‐nitro‐N, N‐di(hydroxyethyl) aniline or 4‐nitrobenzyl chloride via cyclization or condensation and reduction. The structures of HL1—HL4 were verified by 1H NMR, IR spectra, MS and elemental analysis. Moreover, the oxygenation constants (KO2) and thermodynamic parameters (δH0 and δS0) of their cobalt(II) complexes were determined in the range of ?5 °C to 25 °C, and the effect of crown ring bonded to a Schiff base on the dioxygen affinities of cobalt(II) complexes was also observed as compared to the uncrowned analogue (CoL). 相似文献
992.
Sheng Hua Liu 《Journal of organometallic chemistry》2003,683(2):331-336
Treatment of [Ru(CHCHCH2PPh3)X(CO)(PPh3)2]+ (X=Cl, Br) with KTp (Tp=hydridotris(pyrazolyl)borate) and NaBPh4 produced [TpRu(CHCHCH2PPh3)(CO)(PPh3)]BPh4. Reaction of RuHCl(CO)(PPh3)3 with HCCCH(OEt)2 produced Ru(CHCHCH(OEt)2)Cl(CO)(PPh3)2, which reacted with KTp to give TpRu(CHCHCHO)(CO)(PPh3). Treatment of [TpRu(CHCHCH2PPh3)(CO)(PPh3)]BPh4 with NaN(SiMe3)2 and benzaldehyde produced TpRu(CHCHCHCHPh)(CO)(PPh3). The later complex was also produced when TpRu(CHCHCHO)(CO)(PPh3) was treated with PhCH2PPh3Cl/NaN(SiMe3)2. The bimetallic complex [TpRu(CO)(PPh3)]2(μ-CHCHCHCHC6H4CHCHCHCH) was obtained from the reaction of [TpRu(CHCHCH2PPh3)(CO)(PPh3)]BPh4 with NaN(SiMe3)2 and terephthaldicarboxaldehyde. 相似文献
993.
994.
M. A. Aramendía V. Borau C. Jiménez J. M. Marinas F. Rodero M. E. Sempere 《Reaction Kinetics and Catalysis Letters》1992,46(2):305-312
In this work we studied and compared the catalytic activity of various supported Pt systems on the gas-phase hydrogenation of o-, m- and p-xylene. We analyzed the influence of different catalyst preparation variables (solvent, precursor, salt, support and catalyst reduction temperature used) on the catalytic activity and selectivity towards the corresponding cis-and trans-dimethylcyclohexanes.
- o-, m- -. (, , ) - -.相似文献
995.
O. de la Iglesia M. Pedernera R. Mallada Z. Lin J. Rocha J. Coronas J. Santamaría 《Journal of membrane science》2006,280(1-2):867-875
MCM-48 membranes have been prepared on alumina supports of different pore sizes. A battery of characterization techniques has been used to study the physical properties and the quality of the membranes prepared. The highest quality membranes were prepared on supports with pore size of up to 60 nm. The MCM-48 membranes were tested in the separation of gas phase mixtures and a cyclohexane/O2 selectivity higher than 270 was obtained. The selective separation of organic compounds from inert components is a result of the cooperative effects of capillary condensation in MCM-48 pores and of the specific interactions of the permeating compounds and the membrane material. 相似文献
996.
The aim of this work is development of methodology for analysis of inorganic cations (sodium, ammonium, potassium, magnesium
and calcium) in fertilizer industry wastewater. Method development includes optimization of eluent flow rate and concentration
of eluent competing ion in order to obtain optimal separation within reasonable analysis time. For that purpose artificial
neural network retention model was developed and used in combination with normalized resolution product criteria function.
Developed artificial neural network retention model shows good predictive ability R2 ≥ 0.9983. The determined ion chromatographic parameters enable baseline separation of all components of interest. By performing
validation procedure and number of statistical tests it is shown that developed ion chromatographic method has superior performance
characteristic: linearity R2 ≥ 0.9984, recovery = 99.81% − 99.44%, repeatability RSD ≤ 0.52%. That result proves that proposed method can be used for
routine monitoring analysis in fertilizer industry. 相似文献
997.
Jorge Bravo Jesús Castro Soledad García‐Fontn Elvira M. Lamas Pilar Rodríguez‐Seoane 《无机化学与普通化学杂志》2003,629(2):297-302
The manganese carbonyl complex [MnBr(CO)3 L ] ( 1 ), where L = Ph2POCH2CH2OPPh2, was prepared by reacting [MnBr(CO)5] with the bidentate ligand 1, 2‐Bis(diphenylphosphinite)ethane. From this compound and the appropriate phosphite, phosphinite or phosphonite ligands were synthesized the complexes [MnBr(CO)2 LL ′], where L ′ = P(OMe)3 ( 2 ) or P(OEt)3 ( 3 ) and [MnBr(CO)3 L ′2], where L ′ =PPh(OEt)2 ( 4 ) or PPh2(OEt) ( 5 ). The obtained compounds have been characterized by elemental analysis, mass spectrometry, IR and NMR (1H, 13C and 31P) spectroscopies and X‐ray diffractometry for the complexes 1 , 4 and 5 . 相似文献
998.
Viñas P Aguinaga N López-García I Hernandez-Córdoba M 《Journal of AOAC International》2002,85(3):736-743
Procedures were developed for determining cadmium, aluminium, and copper in beer and the products used in its manufacture by electrothermal atomic absorption spectrometry. Beer samples were injected into the furnace and solid samples were introduced as suspensions after preparation in a medium containing hydrogen peroxide, nitric acid, and ammonium dihydrogen phosphate for cadmium atomization. Calibration was performed with aqueous standards, and characteristic masses and detection limits were, respectively, 1 and 0.3 pg for cadmium, 18 and 5.4 pg for aluminium, and 5.6 and 6.8 pg for copper. Different samples of beer, wort, brewer's yeast, malt, raw grain, and hops were analyzed by the proposed procedures. Cadmium was found in low concentrations (0.001-0.08 microg/g and 0-1.3 ng/mL); copper (3-13 microg/g and 25-137 ng/mL) and aluminium (0.6-9 microg/g and 0.1-2 microg/mL) were found at higher levels. The reliability of the procedure was confirmed by comparing the results obtained with others based on microwave oven sample digestion, and by analyzing several certified reference materials. 相似文献
999.
5种贝类脂肪含量及脂肪酸组成研究 总被引:8,自引:0,他引:8
用氯仿 甲醇法测定了广州海鲜市场上棕带仙女蛤、波纹巴非蛤、文蛤、栉孔扇贝和园华扇贝等 5种贝类的脂肪含量 ,并用GC MS法测定了它们的脂肪酸组成。 5种贝类鉴定出的脂肪酸都在 99% (质量分数 )以上。它们的脂肪含量都大于 1% (质量分数 ) ,园华扇贝的脂肪含量最高。它们的ω 3多不饱和脂肪酸与ω 6多不饱和脂肪酸含量的比值基本上都大于 2。两种扇贝的廿碳五烯酸 (EPA)和廿二碳六烯酸 (DHA)含量都比较高。分析结果表明 ,园华扇贝不仅脂肪含量高 ,而且EPA与DHA的含量也比较高 ,是EPA和DHA理想的提取原料 相似文献
1000.
I. López-García E. Navarro P. Viñas M. Hernández-Córdoba 《Analytical and bioanalytical chemistry》1997,357(6):642-646
A method is proposed for the determination of Pb, Cd and Tl in cements by ETAAS. The samples are suspended in a medium containing
10% v/v ethanol and 1% v/v both conc. nitric and hydrofluoric acids and are directly introduced into the electrothermal atomizer.
The drying stage is performed by programming a 400 °C temperature, a ramp time of 5 s and a hold time of 30 s on the power
supply to the atomizer. No ashing step is used. Atomization is carried out at 2100, 1800 and 1700 °C for Pb, Cd and Tl, respectively.
For Cd determination, ammonium dihydrogen phosphate is added to the suspension medium. No modifier other than hydrofluoric
acid is required for the Pb and Tl determination. It is shown that the results obtained by using direct calibration with aqueous
standards for five commercial samples agree with those found by means of the standard additions method.
Received: 29 March 1996/Revised: 24 May 1996/Accepted: 30 May 1996 相似文献