Synthesis of chelating resins and its application in ligand exchange chromatography

Summary Three kinds of new chelating resin containing -hydroxydithiocinnamic acid, ethyl -hydroxydithiocinnamate and N-(hydroxymethyl)-thioamide functional groups were synthesized. Cu(II), Cd(II) and Hg(II) were used as complex forming metal ions. By varying the combination of metal ion and chelating resin, a great variety of separation systems could be realized. For the on-line trace enrichment of 2-mercaptobenzimidazole, the copper-loaded N-(hydroxymethyl)-thioamide concentration column was found most suitable. UV detection at 300 nm was used. The detection limit was 0.2 ng/g. A 10 ml sample was found to be sufficient to attain the described sensitivity, and linear relationship was obtained in the range of 0.75 ng/g to 12 ng/g. The best separation of the thiol compound mixture thioglycolic acid, methionine, cysteine and 2-mercaptoethanol was obtained with copper-loaded ethyl -hydroxydithiocinnamate resin; UV absorbance detection was at 215 nm.     

Differential Pulse Polarographic Determination of Trace Molybdenum in Uranium with α-Benzoinoxime Extraction

A method for the determination of trace molybdenum in uranium is described based on its specific catalytic reduction wave in the presence of nitric acid. Molybdenum is separated from uranium by α-benzoin oxime extraction and determined by differential pulse polarography. As lower as 1 ng/ml of Mo(VI) is determinable and 98% of recovery can be obtained at present work.     

Influence of channel-width ratio on solvent extraction through a double-pass parallel-plate membrane module

The effect of the location of an impermeable barrier, which is placed for double pass in the raffinate phase, on solvent extraction through a parallel-plate membrane module, has been investigated. Theoretical predictions are in fairly good agreement with the experimental results. Considerable improvement in performance is obtainable if the subchannel width, as well as the mass-transfer area, of concurrent flow is as large as possible than that of concurrent flow, especially for low flow rate operation. It has been also checked that the hydraulic dissipated power due to the friction loss of fluid flow is very small and generally, the operating cost in all devices may be ignored.     

Mössbauer Study of Some Gamma- and Neutron-Irradiated Iron Carbonyl Complexes

Mössbauer effect experiments have been carried out on ⁶⁰Co and reactor irradiated CFe(CO)₃SCH₁]₂, [(C₄H₉)₂SnFe(CO)₄]₃, (C₆H₅)₁PFe(CO)₄, (CH₂)₄[Fe(CO)₂C₃H₅]₂, and (CH₂)₄.(CO)₂[Fe(CO)₂C₅H₅]₂. It was found that the Fe—CO bond is rather radiation resistant than are expected due to the π bonding character. The σ bonds such as C—H are labile to radiation. The presence of acyl carbonyl group increase the radiation resistant property of the molecule. The increase in the isomer shift values of the complexes with cyclopentadienyl groups were interpreted as a result of dehydrogenation.     

Electrophoresis of a spherical particle along the axis of a cylindrical pore filled with a Carreau fluid

The electrophoresis of a spherical particle along the axis of a cylindrical pore filled with a Carreau fluid is investigated theoretically. In addition to the boundary effect due to the presence of the pore, the influences of the thickness of double layer surrounding a particle and the properties of the fluid on the electrophoretic behavior of the particle are also examined. We show that, in general, the presence of the pore has the effect of retarding the movement of a particle. On the other hand, the shear-thinning nature of the liquid phase is advantageous to its movement. For both Newtonian and Carreau fluids, the mobility of a particle increases monotonically with the decrease in the thickness of double layer, but the mobility is more sensitive to the variation of the thickness of double layer in the latter. The mobility of a particle in a Carreau fluid is larger than that in the corresponding Newtonian fluid, and the difference between the two increases with the decrease in double-layer thickness; in addition, depending upon the values of the parameters assumed, the percentage difference can be in the order of 50%.     

Syntheses of 5‐(3‐Arylsydnon‐4‐yl)Tetrazole Derivatives

3‐Arylsydnone‐4‐carbohydroximic acid chlorides ( 1 ) could react with sodium azide to produce the corresponding 3‐arylsydnone‐4‐carbazidoximes ( 2 ), but not 1‐hydroxytetrazoles 3 . Treatment of 3‐arylsydnone‐4‐carbazidoximes ( 2 ) with acid chlorides such as acetyl chloride ( 4a ), propionyl chloride ( 4b ) and benzoyl chloride ( 4c ) in the presence of excess triethylamine generated the derivatives of the azidoximes 5 . To obtain the desired tetrazoles, the azidoximes 2 should first cyclize directly with acetyl chloride ( 4a ) or propionyl chloride ( 4b ) to afford the acetyl or propionyl derivatives 6 . The cyclized tetrazole derivatives 6 underwent deacylation upon heating in ethanol to give 1‐hydroxy‐5‐(3‐arylsydnon‐4‐yl)tetrazoles ( 3 ).     

Luminescent silver metal chains with unusual mu4-bonded 2,2'-bipyrazine

An unusual mu4-bridging bonding mode of 2,2'-bipyrazine is observed for the first time in a luminescent coordination polymer [Ag2(bpyz)(NO3)2]n, which comprises of silver chains with alternating strong and weak Ag...Ag interactions.