Synthesis, structure and properties of alpha-Keggin-type of K6H3[ZnW11O40Al]center dot 9.5H(2)O

A new heteropolycomplex, K6H3[ZnW11O40Al] . 9.5H(2)O was prepared and characterized by means of elemental analysis, IR, UV spectroscopy, Al-27 NMR, electrochemistry and X-ray crystallography. The crystal of K6H3[ZnW11O40Al] . 9.5H(2)O is cubic, space group Fm-3m, with lattice constants a=b=c=2. 144 8(2) nm, V = 9.866(2) nm(3), Mo radiation, R = 0.057 8 for 497 independent data with [I>2 delta(I)]. The anion is of alpha-type Keggin structure with C-s symmetry.

The chemistry of alpha-oxo ketene cyclic dithioacetal .36. Studies on silica G catalyzed decomposition of adducts of beta,beta-1,3-propylenedithio-alpha,beta-unsaturated arylketones with grignard reagents

beta, beta-1, 3-Piopylenedithio-alpha, beta-unsaturated arylketones 2 via chemoselective 1,2-addition with allyl or benzyl Grignard reagents afforded the corresponding carbinols 3 and 4. Catalysed by silica gel, the carbinols 3 and 4 were converted to the beta,gamma-unsaturated arylketones 5, 6. The mechanism and reaction condition were discussed.

Crystalline behavior and critical crystalline sequence length of propylene/alpha-olefin copolymer

The melting points(T-m), crystalline temperature(T-c) and crystallinity(chi(c)) of propylene/alpha-olefin (pentene-l, octene-1 and decene-1) copolymers have been investigated, The results show that the T-m, T-c and chi(c) of the copolymers are lower than those of propylene homopolymer, indicating that lower alpha-olefin incorporation in copolymer has strongly hampered the crystallization of propylene, From critical crystalline sequence length of several propylene/alpha-olefin copolymers, it can be seen that a long chain alpha-olefin has much stronger effect on crystallization of PP than a short alpha-olefin does.

Stereochemical effect in mass spectrometry .19. Determination of the optical purity of alpha-phenylethylamine by mass spectrometry

It is found that in the fast atom bombardment (FAB) mass spectra R-alpha-phenylethylamine and S-alpha-phenylethylamine can be clearly distinguished by S-1,1'-binaphthyl-2, 2'-diylhydrogenphosphate (S-BNP), Mixture of R-alpha-phenylethylamine and S-alpha-phenylethylamine also be tested and the relative abundance of the characteristic ion of mixture is related to the composition of the mixtute. We have therefore proposed a possible method to determine the optical purity of alpha-phenylethylamine.

SYNTHESIS AND CHARACTERIZATION OF ALPHA,BETA-TRIINDIUM SUBSTITUTED HETEROPOLYTUNGSTATES

The complexes of alpha,beta-K(a)H(b)XW(9)O(37)(InH2O)(3) . xH(2)O (X = Si, Ge; a+b = 7) were synthesized from their lacunary precursors alpha,beta-XW(9)O(34)(10-) (X = Si, Ge) and characterized by elemental analysis, W-183 NMR, IR and UV spectroscopy and polarography. W-183 NMR spectra of the title complexes consist of two lines with intensity ratio 2:1, as expected for the C-3 nu structure of trisubstituted A alpha- and A beta-Keggin anions.

SYNTHESIS AND PROPERTIES OF ALPHA-MOLYBDOTUNGSTONIOBIC DIPHOSPHATES

Four kinds of new molybdotungstoniobic diphosphates with the Dawson structure, formulated as alpha-P2W15Mo2Nb62(7-), are prepared and characterized by IR, UV spectra, polarography and W-183 NMR which show that the same ''polar'' W atoms in the Dawson frames-are substituted. The mean value of W-183 chemical shifts of the ''polar'' group varies linearly with the number of substituted atoms in the opposite polar group.

DETERMINATION OF AMINOPYRINE AND ITS METABOLITE IN BIOLOGICAL FLUID BY LIQUID-CHROMATOGRAPHY ELECTROCHEMISTRY WITH A GLASSY-CARBON ELECTRODE DISPERSED WITH ALPHA-ALUMINA PARTICLES

A sensitive high-performance liquid chromatographic method has been developed for the quantitative determination of aminopyrine (AM) and its metabolite 4-aminoantipyrine (AAN). The method utilizes reverse-phase chromatography/amperometric detection with a glassy carbon electrode dispersed with alpha-arumina particles as the working electrode, on which the oxidation of AM and AAN was greatly improved compared with that on a bare glassy carbon electrode. As a result, the detection limit was as low as 1.4 ng for AM and 0.8 ng for AAN, and the calibration plots for the above compounds have wide linear ranges from 100 ng/mL to 100 mu g/mL and 60 ng/mL to 80 mu g/mL (for AM and AAN, respectively). The above method was applied for the detection of these materials in human urine with satisfactory results.

SOME NEWER CONCEPTS OF ETHYLENE ALPHA-OLEFIN COPOLYMERIZATION ON HETEROGENEOUS ZIEGLER-NATTA CATALYSTS

Unsteady diffusion kinetic, recently advanced by this laboratory, is applied to the examination of some polymerization and molecular chain structure problems. Hitherto deemed "anomalous" phenomena, such as the faster rate of copolymerization of ethylene/alpha-olefin than the homopolymerization of ethylene and the enrichment in the incorporation of a higher alpha-olefin in its copolymerization with ethylene by a lower alpha-olefin, are reasonably explained by unsteady diffusion of monomers. Molecular chain structure of copolymers, such as compositional heterogeneity and its dependence on comonomer incorporation originates from the difference in diffusion coefficients of the monomers. A copolymer composition equation taking into consideration the unsteady diffusion was developed. In cases where simulated curves were compared with experimental curves, good agreements were found.

SYNTHESIS AND MOLECULAR-STRUCTURE OF THE 5-COORDINATE ZIRCONIUM COMPLEX (CH3C5H4)2ZRCL(ALPHA-C10H7COO)

Bis(methylcyclopentadienyl)chloro(alpha-naphthoyloxy)zirconium, (CH3C5H4)2Zr Cl(alpha-C10H7COO), has been synthesized by the reaction between (MeCp)2ZrCl2 and equimolar sodium alpha-naphthoate in toluene at room temperature. The molecular structure of the title complex was determined by X-ray diffraction. The molecules have a five-coordinate bent metallocene structure in which the alpha-naphthoxyligand is bidentate [Zr-O, 2.317(2), 2.260(2) angstrom]. The remaining distances are [Zr-Cl, 2.521(1) angstrom; Zr-C, 480-2, 565 angstrom; Zr-cent-CH3C5H4 2.217 and 2.230 angstrom].

GENERAL ALPHA-N INDEX AND ITS APPLICATION .2. THE CORRELATION BETWEEN THE GENERAL ALPHA-N INDEX AND PHYSICAL-PROPERTIES OF NEUTRAL PHOSPHORUS-COMPOUNDS

The relationship between the alpha-N index and physical properties of neutral phosphorus extractants is studied. Using the general alpha-N index which could describe extractants with minute difference in structure, the good correlation between it and various physical properties of the neutral phosphorus extractants (e.g., densities, refractive index, shift ratio of paper chromatography and IR frequencies of bond P = O) is obtained. The result indicates that general alpha-N index is a good topological index of organic compounds.

A GLASSY-CARBON ELECTRODE MODIFIED BY DISPERSED ALPHA-ALUMINA AS AN ENHANCED ELECTROCHEMICAL DETECTOR IN LIQUID-CHROMATOGRAPHY FOR CYSTEINE AND GLUTATHIONE

The dispersion of alumina particles on a glassy-carbon surface serving as a modified electrode significantly enhances the amperometric detection of cysteine and glutathione following liquid chromatography. With an applied potential of 0.8 V vs. SCE, the detection limits were 1.2 ng for cysteine and 8 ng for glutathione and the electrode response was linear up to 600 ng for cysteine and 1.8-mu-g for glutathione. The modified electrode displayed high sensitivity and stability and was easy and inexpensive to prepare.

THE CATALYTIC BEHAVIOR AND REACTION-MECHANISM OF THE BI-CE-O SYSTEM CATALYSTS IN THE OXIDATIVE DEHYDROAROMATIZATION OF PROPYLENE

Oxidative dehydroaromatization of propylene was investigated by the pulse technique over two kinds of single oxide catalysts. With the Bi2O3 catalyst, the main dimer product was 1,5-hexadiene, and the dimerization activity was stable to pulse number even if the catalyst was partly reduced to the bulk. With the CeO2 catalyst, benzene was mainly formed instead of 1,5-hexadiene, but the activity decreased rapidly with increasing pulse number, indicating that only the lattice oxygen near the catalyst surface could be used for oxidative dimerization and the further aromatization. The Bi-Ce-O system catalyst was found in this study to give higher aromatization activity and showed better stability, compared to the Bi-Sn-O catalyst. Although the Bi-Ce-O catalyst was only a mixture of the two component oxides from X-ray diffraction analysis, there was a significant combination effect on the selectivity to benzene. The highest and the most stable selectivity of benzene was obtained at Bi/Ce = 1. In the TPD spectrum of Bi-Ce-O catalyst, there are not only the lattice oxygen (beta-oxygen) over 620-degrees-C due to the reduction of Bi2O3, but also a great deal of the alpha-oxygen desorbed about 400-degrees-C, which is considered the absorbed oxygen in the bulk. This absorbed oxygen could probably be a compensation of the lattice oxygen through the route of gaseous --> absorbed --> lattice oxygen in the binary catalyst system. By the kinetic study on the Bi-Ce-O catalyst, the dimer formation rate was the first-order with respect to the partial pressure of propylene and zero-order of oxygen. Although detail investigation would be made further, it was considered that the complete oxidation of propylene would mainly take place parallelly on some different sites, and the rate-determining step of propylene dimerization occurred probably between an adosrbed propylene and a gaseous one by an Eley-Rideal type mechanism.

CRYSTAL AND MOLECULAR STRUCTURES AND MS ANALYSE OF beta-CARBOXYLETHYL (OR alpha-METHYLETHYL) GERMANIUM TRICHLORIDES

This paper reports the results of the crystal and molecular structures, CI-MS and FAB-MS analyse of Cl3GeCH2CH2COOH and Cl3GeCH(CH3)CH2COOH. The characters and active parts of these molecules are also discussed

GENERAL ALPHA-N INDEX AND ITS APPLICATION .1. GENERAL ALPHA-N INDEX AND ITS APPLICATION IN THE EXTRACTION OF Y, CE, U, AND TH BY NEUTRAL PHOSPHORUS EXTRACTANCTS

The general a(N) index is established for molecules containing heteroatoms, rings, and multiple bonds. The general a(N) index is able to describe molecules with minute differences in structure and can also reveal the properties of molecules. This theory is successfully applied to the case of neutral phosphorus extractants. Both the molecular polarity and steric effect are characterized by the general a(N) index. The relationships between these properties and the distribution ratios for extracting Y, Ce, U, and Th are also shown by the general a(N) index.