Zur Erkennung der Chlorchroms?ure

Ohne Zusammenfassung     

A Mössbauer-effect study of the isomer shifts of iron in nickel aluminides

The room-temperature isomer shifts of iron in nickel aluminides have been measured. A single Mössbauer-resonance line is observed for alloys of composition (NiAl)_100-cFe_c, 0 ? c ? 5 at. %, and Al₅₀Ni^50-cFec, 2 ? c ? 50 at. %. The isomer shift for dilute Fe concentration in stoichiometric NiAl is compared with that for FeAl at stoichiometric composition.     

Synthesis of porous wires from directed assemblies of nanospheres

A method is reported for the fabrication of wires with extended pore structures. Nanospheres are initially infiltrated into the one-dimensional channels of alumina or polymer porous membranes. Metal is then electrochemically deposited within the channels. Removal of the membrane and nanospheres results in porous wires. The production of 1-mum diameter wires with 300- or 500-nm diameter pores and 300-nm diameter wires with 140-nm pores illustrates the utility of this approach. Contacts between the spheres and the channel wall result in openings on the surface of the wires, and contacts between the spheres themselves produce openings between adjacent pores. Some short-range ordering of the spheres within the channels, as reflected in the wire pore structure, is evident. Characterization of the porous wires by electron microscopy is presented, and the potential applications of materials is discussed.     

Crystal and molecular structure of 1-chloro-1,2-benziodoxolin-3(1H)-one·tetra-n-butylammonium chloride

The title compound,6, a novel 11 complex of 1-chloro-1,2-benziodoxolin-3(1H)-one (5) andtetra-n-butylammonium chloride, was prepared from tetra-n-butylammoniumo-iodoxybenzoate (7) and acetyl chloride. A single crystal of6 was subjected to X-ray analysis: triclinic, space group a=10.239(2),b=11.518(2),c=11.523(3)Å; =73.20(2); =87.85(2), =87.72(2)°; R1=0.0326. The most notable structural feature of crystalline6 is the existence of a secondary bond [I· ·Cl(2), 2.943(1)Å] between the chloride ion and the iodine atom of the chlorobenziodoxolinone moiety. Further coordination at iodine includes three primary bonds: I–C [2.115(4) Å], I–O [2.145(3) Å], I–Cl(1) [2.454(1) Å]. The entire 1-chlorobenziodoxolinone-chloride sub-structure is planar and exhibits iodine-centered bond angles of 78.8(1)° [C–I–O], 92.0(1)° [C–I–Cl(1)], 97.6(1)° [Cl(2)–I–O] and 91.6(1)° [Cl(2)–I–Cl(1)]. The unit cell of6 contains two loosely packed formula units. The chlorobenziodoxolinone-chloride sub-structures occupy a common plane and exhibit a centrosymmetric relationship, while the tetra-n-butylammonium ions are situated one above and one below the plane. Bonding at the iodine atom in6 is more consistent with a 10-I-3 species electrostatically associated with the chloride ion than a 12-I-4 species such as the tetrachloroiodate ion.     

Mass Spectral Characteristics of Pivalolactone and Polypivalolactone

The mass spectral characteristics of pivalolactone and its polymer have been determined. The monomeric lactone (MW 100) shows no molecular ion peak but does show peaks at 70 and 42 m/e associated with the loss of formaldehyde and then carbon monoxide and at 56 and 41 associated with the loss of isobutene and carbon dioxide. Only weak peaks, corresponding to the presence of traces of oligomers, are observed above m/e 71. The polymer, at volatilization temperatures of 250-350°C, gives fragments of up to 1242 m/e with a pattern recurring over intervals of 100 m/e units. The principal peaks occur at X42, X70, X83, and X01 m/e. Above 301, the X42 and X70 peaks are observable up to X = 12. The X70 fragment is assigned an acylium isobutyrate radical ion structure and the X42 fragment is assigned an isobutyl radical ion structure. The degradation products are accounted for as being formed from volatilized cyclic oligomers.     

Reactivity Ratios for Divinylbenzene and Ethylene Glycol Dimethacrylate Copolymerizations with Styrene and Methyl Methacrylate

The free radical copolymerization of styrene and other vinyl monomers to produce cross-linked, network polymers is of technological importance in the production of ion-exchange resins, packings for gas-liquid and gel permeation chromatography, cross-linked latex polymers, and other products. The principal multifunctional cross-linking monomers which are used in this connection are ethylene glycol dimethacrylate and divinylbenzenes, and accurate values for reactivity ratios in their reactions with bifunctional monomers are essential for the design of copolymerization processes and products.

Wiley and co-workers have reported reactivity ratios for the copolymerizations of these monomers with styrene and with methyl methacrylate [1]. In these studies the reactivity ratios were calculated from the raw data using a graphical “method of intersections” [2]. In this procedure the differential copolymer equation is put into the form     

Field Desorption Mass Spectral Data for Oligomers up to 2400 Amu

Field desorption mass spectra of oligomers show peaks of mass up to 2400 amu.     

Monomer Reactivity Ratios from High Conversion Copolymerization of Styrene with meta- and with para-Divinylbenzene

The copolymerization reactivity ratios for styrene/m- and styrene/p-divinylbenzene have been determined at high conversions (<35%) using the integrated form of the copolymerization equation. Values of r₁ (s) = 1.11, r₂ (m) = 1.00; and r₁ (s) = 0.20, r₂ (p) = 1.00 were obtained. These values indicate the same relative behavior but are quantitatively different from the differential data. The data confirm that the para isomer is incorporated more rapidly into the growing polymer chain than is the meta isomer.