LIQUID-LIQUID EXTRACTION STUDIES OF METAL IONS WITH DIAZACROWN AND STRUCTURE ANALOGOUS OPEN-CHAIN COMPOUNOS

1,10-diaze [8]crown-6, their N,N'-dibutyl- and dioctyl-substituted derivatives and the structure analogous open-chein tetreoxedieza slkanee have been synthesized in order to examine the extraction properties for Na⁺, K⁺, Sr²⁺ and Hg²⁺. It wes found, that the extraction of strontium, potassium and sodium picratee with azacrown compounds ie much higher than that with open-chein oxaaze alkanes. 1,10-diaze [18] erown-6 has a good selectivity for the extraction of Sr²⁺ over K⁺ and Na in alkaline solution. In the case of Sr²⁺ the diffarencea between tha various azacrown compounds are email, whereea in the caee of K⁺ and Na the substituted derivativee are better extractante. Theserssulte correspond qualitativsly with tha order of stebility conetantB in protic solvsnts. The extrectebility of N,N'-dioctyl-l, 10-dieze[18]crown-6 for HgCl₂ is very high. Contrerv to the order of stability conetants the uneubetituted conpound do not extract mercury under the choeen experimental condition*. The extraction power of open-chain conpounde ie aleo high and strong Influenced by the alkyl eubatltuente at the nitrogen donor stons,     

THIRD PHASE FORMATION IN EXTRACTION OF THORIUM NITRATE BY MIXTURES OF TRIALKYL PHOSPHATES

ABSTRACT

This paper reports the results of the studies on third phase formation during the extraction of thorium nitrate from zero free acidity solutions by mixtures of trialkyl phosphates. The phosphates used are tri n-butyl phosphate(TBP), triiso butyl phosphate(TiBP), tri sec butyl phosphate (TsBP) and tri n-amyl phosphate(TAP). The results indicate that small additions of a homologous phosphate can alter the Limiting Organic Concentration (LOC) above which the third phase formation takes place and thus can be advantageously utilised. Use of mixtures of the trialkyl phosphates as extractant can thus obviate the need for adding modifiers such as alcohols to the organic phase for avoiding third phase formation.     

Effect of Humidity on NPK Fertilizer Drying

ABSTRACT

The drying process within rotary coolers during the manufacture of granular NPK fertilizer plays an important role in the production of fertilizer granules possessing both a low moisture content and low caking propensity. A theory for fertilizer drying has been developed which takes into account the low critical relative humidity of complex fertilizer found at high temperature. The theory proposes that the gradient between the partial vapour pressure of moisture in the air and the vapour pressure moisture adjacent to the surface of the fertilizer granule, is the rate controlling stage in the drying of hot granular fertilizer rather than the internal diffusion of moisture within the particle.     

Bupropion and cognitive-behavioral treatment for depression in smoking cessation.

This study is a randomized, double-blind, placebo-controlled clinical trial examining the effects of an intensive cognitive-behavioral mood management treatment (CBTD) and of bupropion, both singularly and in combination, on smoking cessation in adult smokers. As an extension of our previous work, we planned to examine the synergistic effects of CBTD and bupropion on smoking cessation outcomes in general and among smokers with depression vulnerability factors. Participants were 524 smokers (47.5% female, M (age) = 44.27 years) who were randomized to one of four 12-week treatments: (a) standard, cognitive-behavioral smoking cessation treatment (ST) plus bupropion (BUP), (b) ST plus placebo (PLAC), (c) standard cessation treatment combined with cognitive-behavioral treatment for depression (CBTD) plus BUP, and (d) CBTD plus PLAC. Follow-up assessments were conducted 2, 6, and 12 months after treatment, and self-reported abstinence was verified biochemically. Consistent with previous studies, bupropion, in comparison with placebo, resulted in better smoking outcomes in both intensive group treatments. Adding CBTD to standard intensive group treatment did not result in improved smoking cessation outcomes. In addition, neither CBTD nor bupropion, either alone or in combination, was differentially effective for smokers with single-past-episode major depressive disorder (MDD), recurrent MDD, or elevated depressive symptoms. However, findings with regard to recurrent MDD and elevated depressive symptoms should be interpreted with caution given the low rate of recurrent MDD and the low level of depressive symptoms in our sample. An a priori test of treatment effects in smokers with these depression vulnerability factors is warranted in future clinical trials.     

Decolorization of Methyl Orange Dye at IrO2‐SnO2‐Sb2O5 Coated Titanium Anodes

A film of iridium and tin dioxides doped with antimony oxide (IrO₂‐SnO₂‐Sb₂O₅) was deposited onto Ti mesh and plate substrates by the Pechini method. The electrode surface morphology and composition were characterized by SEM‐EDS. The ternary oxide coating was used for the anodic oxidation of methyl orange (MO) azo dye. Linear sweep voltammetry was used to identify the electrode potentials that favour MO degradation. Batch electrolyses were then carried out at a constant electrode potential of 1.5, 1.75 and 2.0 V vs. SHE using either a three‐electrode batch cell or a flow reactor. The dye solutions were totally decolorized via reactive oxygen species, such as ^?OH, H₂O₂ and O₃ formed in situ from water oxidation at the Ti/IrO₂‐SnO₂‐Sb₂O₅ surface.     

Metabolic Fate of the Environmental Mutagen 3-Nitrofluoranthene in the Rat

3-Nitrofluoranthene, a potent environmental mutagen, was administered to rats intraperitoneally at 10 mg/kg, labelled with ¹⁴C. Urine contained 15 to 20% of the dose, eliminated mainly within the first 24 hours after dosing. Over 95% of the radioactivity in unhydrolysed urine chromatographed with the solvent front in a reverse-phase HPLC system, indicating extensive conjugation. After hydrolysis with β-glucuronidase (containing sulfatase) and concentration on C18-Sep-Pak, urine was fractionated by HPLC for further characterization. NMR analysis of the metabolite fractions indicated that positions 4, 8 and 9 were major sites of oxidation. Both acetamide and amine derivatives were formed. The finding of multiple oxidation and incomplete acetylation is in contrast to the fate of 1-nitropyrene, where 1-acetamidopyren-6-ol, itself a potent mutagen, represents the major metabolic product. This difference in metabolism pathways may have implications for the genotoxicity of 3-nitrofluoranthene.     

Analysis of Polycyclic Aromatic Compounds Using Microbore Columns

The gas chromatographic analysis of polycyclic aromatic compounds can be completed faster and with increased chromatographic resolution using microbore columns (Fast GC). Microbore columns contain two to three times the number of theoretical plates per meter when compared to 0.25 mm internal diameter (i.d.) capillary columns. The increased chromatographic resolving power of microbore columns enables separations to be carried out with much shorter columns giving rise to faster analysis times. Analysis times of priority polycyclic aromatic hydrocarbons on 20 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) and 10 m (5% phenyl, 0.1 mm i.d., 0.1 w m film thickness) columns are reduced by about 45% and 60% respectively in comparison with 30 m columns, and data quality (precision and accuracy) is not affected. All areas/parameters of the chromatographic system must be adjusted and optimized to ensure proper chromatographic performance. Smaller injection volumes (0.2-0.5 w L) and injection liners (1-2 mm i.d.) are required to obtain optimum (and reproducible) chromatography on 0.1 mm i.d. columns.