Recovery and Reduction of Spent Nickel Oxide Catalyst via Plasma Sintering Technique

A thermal plasma process for the recovery and reduction of nickel oxide in the spent nickel-based catalyst (NiO/SiO₂) was developed. The spent catalyst was sintered at >1,500 °C under plasma condition and the nickel oxide therein was reduced to nickel, which was proven by XRD and EDX. By application of SEM and GC technique, the organic tar on the surface of the spent catalyst was found to decomposed and converted to syngas (CO, CO₂, and H₂), which might be the reducing agents in the process. A gasification mechanism for the generation of syngas and the reduction of nickel oxide under plasma conditions was proposed.     

Comparing micellar electrokinetic chromatography and microemulsion electrokinetic chromatography for the analysis of preservatives in pharmaceutical and cosmetic products

In this study, separation and determination of nine preservatives ranging from hydrophilic to hydrophobic properties, which are commonly used as additives in various pharmaceutical and cosmetic products, by micellar electrokinetic chromatograpy (MEKC) and microemulsion electrokinetic chromatography (MEEKC) were compared. The effect of temperature, buffer pH, and concentration of surfactant on separation were examined. In MEKC, the separation resolution of preservatives improved markedly by changing the sodium dodecyl sulfate concentration. Temperature and pH of running buffers were used mainly to shorten the magnitude of separation time. However, in order to detect all preservatives in a single run in a MEEKC system, a microemulsion of higher pH was needed. The separation resolution was improved dramatically by changing temperature, and a higher concentration of SDS was necessary for maintaining a stable microemulsion solution, therefore the separation of the nine preservatives in MEEKC took longer than in MEKC. An optimum MEKC method for separation of the nine preservatives was obtained within 9.0 min with a running buffer of pH 9.0 containing 20 mM SDS at 25 degrees C. A separation with baseline resolution was also obtained within 16 min using a microemulsion of pH 9.5 which composed of SDS, 1-butanol, and octane, and a shorter capillary column at 34 degrees C. Finally, the developed MEKC and MEEKC methods determined successfully preservatives in various cosmetic and pharmaceutical products.     

Sydnone Compounds. XX. The Synthesis and the Schmidt Reaction of 4-Formyl-3-Arylsydnone

A convenient method to prepare 4-formyl-3-arylsydone (I) from 3-arylsydnone by the Vilsmeier reaction in moderate yields (30%-76%) was carefully investigated. According to the Schmidt reaction, I reacts with sodium azide in concentrated sulfuric acid to produce 3-arylsydnone-4-carboxamide (II). But 3-arylsydnone-4-carhonitrile (III) is obtained, if dilute sulfuric acid was used instead. When III treates with concentrated sulfuric acid, II is obtained in good yield. The all possible reaction mechanisms are suggested.     

Preparation of 3-Aryl-4-(5-ARYL-Δ2-1,2,4-Oxadiazolin-3-YL)Sydnones and their Conversion into 3-ARYL-4-(5-ARYL-1,2,4-Oxadiazol-3-YL)Sydnones

3-Aryl-4-(5-aryl-Δ²-1,2,4-oxadiazolin-3-yl)sydnones (5) were synthesized in high yields by the reaction of 3-arylsydnone-4-carboxamide oximes (prepared from the corresponding 3-arylsydnone-4-carbonitriles) with aromatic aldehydes in the presence of acid catalysts. No reaction occurred when aliphatic aldehydes were used. The oxadiazolin-3-ylsydnones (5) were easily converted into the corresponding 3-aryl-4-(5-aryl-1,2,4-oxadiazol-3-yl)sydnones by N-bromosuccinimide oxidation. The 3-arylsydnone-4-carbonitrile oxides were synthesized in good yields by N-bromosuccinimide oxidation of the corresponding 3-arylsydnone-4-carboxaldehyde oximes.     

The new genotypic human calicivirus isolated in Seoul

A new type of human calicivirus (HuCV) showing the classic cup-shaped surface morphology was identified in the stool sample from a child with symptoms of acute gastroenteritis in Seoul, Korea (SK virus). Genomic RNA was extracted directly from the stool sample, and the nucleotide sequence of 3.2 kb of the 3' end of SK virus was determined from cDNA. This region spanned sequences from the RNA-dependent RNA polymerase (RDRP) region in the open reading frame 1 (ORF1) to the 3' poly A tail. The non-structural and capsid protein coding sequences were fused in a single ORF as observed in Manchester type (Genogroup III). However, ORF2 of Manchester virus was missing in SK virus. In RDRP region, SK virus showed amino acid and nucleotide identities of 74-75% and 68-69% respectively, with those of Manchester virus, while showed 34-46% and 55-60% identities respectively with those of other human caliciviruses. However, capsid protein of SK virus showed a partial (29-46%) amino acid identity with those of other caliciviruses including Manchester type. The closest resemblance in amino acid (97-99%) and nucleotide sequence (85-86%) identities were found in RDRP region with Vanderbijlpark and Pretoria isolates recently found in South Africa. These results suggest that SK virus together with Vanderbijlpark and Pretoria isolates belong to a new type different from Manchester virus.     

Mononuclear and dinuclear copper(I) complexes of bis(3,5-dimethylpyrazol-1-yl)methane: synthesis, structure, and reactivity

The synthesis and structures of a mononuclear copper(I) carbonyl complex [Cu(OClO3)(CO)(H2CPz2')] (3) and a dinuclear copper(I) carbonyl complex [{Cu(CO)(H2CPz2')}2(mu-pyrazine)](ClO4)2 (4), where H2CPz2' = bis(3,5-dimethylpyrazol-1-yl)methane, are described. These two compounds were generated by the carbonylation of the corresponding copper(I)-acetonitrile complexes, [Cu(H2CPz2')(MeCN)](ClO4) (1) and [{Cu(H2CPz2')(MeCN)}2(mu-pyrazine)](ClO4)2 (2). Alternatively, treatment of mononuclear 1 and 3, respectively, with pyrazine in a molar ratio of 2:1 produces the pyrazine-bridged dinuclear Cu(I) complexes 2 and 4. Each of the complexes 1-4 can react with PPh3 to generate a common three-coordinated copper(I) complex [Cu(PPh3)(H2CPz2')](ClO4) (5). The structures of complexes 1-5 were all confirmed by X-ray crystallography. Comparison of the Cu(I)-C(CO) bond distances and the CO stretching frequencies of 3 and 4 indicates the back-donating properties of d pi(Cu)-pi*(pyrazine) bonds in 4, and accordingly, stabilizes the mixed-valence species generated from 2. Complex 3, stabilized by the strong interaction between copper(I) ion and perchlorate counteranion (Cu(I)-O(ClO4) = 2.240(3) A), is a potential precursor for polynuclear copper(I) carbonyl complexes.     

Synthesis and Crystal Structure of the Dicopper(II) Complex [Cu2{Ph2P(=O)(o‐C6H4)CO2}2(THF)2(H2O)2][BF4]2 by Oxidation of [Cu{Ph2P(o‐C6H4)C(=O)H}2(NCMe)][BF4] with Aqueous H2O2

Treatment of [Cu(pcho)₂(NCMe)][BF₄] 1 (pcho = 2‐(diphenylphosphino)benzaldehyde) with aqueous H₂O₂ in THF solvent affords [Cu₂(dpb)₂(THF)₂(H₂O)₂] [BF₄]₂ 2 (dpb = 2‐(diphenylphosphinoxide)‐benzoate) after crystallization from diethyl ether. This reaction involves oxidation of Cu(I) to Cu(II) ion, phosphine to phosphinoxide, and benzaldehyde to benzoate species. The crystal structure of 2 consists of two copper(II) atoms bridged by two carboxylate moieties of the dpb ligands. The coordination about each copper(II) atom is a distorted trigonal bipyramid.     

Intercomparison of the Asaro-Perlman and Brookhaven archaeological ceramic analytical standards

Two fundamentally different standardization systems, widely used in the neutron activation analysis of archaeological ceramics and of other materials, have been intercompared using procedures of high precision. The results should permit data standardized under either system to be transformed to the opposite system. The two systems are generally known as the Asaro-Perlman standard and the BNL Six-Rocks standard.     

Determination of Isobutanol in Phosphoric Acid by Gas Chromatography

Isobutanol in phosphoric acid was detected by gas chromatography with a flame ionization detector. Samples with high content (>100 μg/ml) of isobutanol were diluted with a n-pentanol aqueous solution and the diluted solutions were directly injected into the GC column for the determination of isobutanol. For lower content samples, isobutanol was preconcentrated by vacuum distillation or CCl₄ extraction followed by activated alumina adsorption. In whole GC measurements, n-pentanol was used as an internal standard. The flame ionization detector is capable of detecting quantities of isobutanol as small as 5×10^?8g. With preconcentration, isobutanol at the concentration of 0.4 μg/ml or lower can be determined.     

Transition Metal Cation Salts in Organic Synthesis

Reaction of lithium diisopropylamide (LDA) with (η⁴-1,3-cyclohexadiene)Fe(CO)₃ complexes bearing functionalized side chains at C-5, under an atmosphere of carbon monoxide, gives bridged bicyclo[3,2,1]octene and bicyclo[3,3,1]nonene systems after electrophilic quenching. Under the same reaction conditions, intramolecular cyclization of acyclic (η⁴- 1,3-butadiene)Fe(CO)₃ complexes with functionalized side chains at the terminal position of the diene ligands furnishes fused bicyclo[3.3,0]octanone and bicyclo[4.3.0]nonanone derivatives after acid quenching. The addition of a variety of the highly functionalized zinc-copper reagents RCu(CN)ZnI to the (η⁷-cycloheptatrienyl)Cr(CO) gives (η⁶-cyclohepta-1,3,5-triene)Cr(CO)₃ complexes with a functionalized side-chain at the C-7 position of the ring. Intramolecular cyclization of ester-subsbtuted adducts using lithium diisopropylamide generates fused bicyclo[5.3.0]decane and bicyclo[5.4.0]undecane derivatives. The addition of a variety of the highly functionalized zinc-copper reagents RCu(CN)Znl to the (η⁴-cyclohexa-1,3-diene)Mo(CO)₂(Cp) at the terminus of the coordinated diene ligand gives [Mo(π-allyl)(CO)₂(Cp)](Cp = cyclopentadienyl) complexes with the functionalized side-chain at the C-4 position of the ring. Intramolecular cyclization of the (π-allyl)molybdenum complex containing a pendant propanoic acid unit generates the δ-lactone derivative.