Co-complexing agents

Highly active catalysts with reduced induction periods are obtained by adding a polyether, poly (butane-1,4-diol), as a co-complexing agent or using CaCl2-modified Zn-Co(III) DMC. The resulting poly(POx) shows a very low unsaturation level (0.003-0.006 mequiv. g ) and a narrow molar mass distribution (D= 1.02-1.04). 

Scheme 1.1 Schematic Representation of a Zn-Co-DMC with tert-Butanol and ROH as Complexing and Co-Complexing Agents, Respectively.

The presence of redox catalysts in the electrode coatings is not essential in the c s cited alx)ve because the entrapped redox species are of sufficient quantity to provide redox conductivity. However, the presence of an additional redox catalyst may be useful to support redox conductivity or when specific chemical redox catalysis is used. An excellent example of the latter is an analytical electrode for the low level detection of alkylating agents using a vitamin 8,2 epoxy polymer on basal plane pyrolytic graphite The preconcentration step involves irreversible oxidative addition of R-X to the Co complex (see Scheme 8, Sect. 4.4). The detection by reductive voltammetry, in a two electron step, releases R that can be protonated in the medium. Simultaneously the original Co complex is restored and the electrode can be re-used. Reproducible relations between preconcentration times as well as R-X concentrations in the test solutions and voltammetric peak currents were established. The detection limit for methyl iodide is in the submicromolar range. 

Mobilization of inicronutrients such as Zn, Mn, Cu, and Co and of heavy metals (Cd, Ni) in soil extraction experiments with root exudates isolated from various axenically grown plants is well documented (61,204-206) and has been related to the presence of complexing agents. 

Experimental verification of the observational inferences is complicated by the difficulty of performing mineral/fluid partitioning experiments at high temperatures and pressures and their dependence on /O2 and complexing agents in the fluid (especially COs and Cl ). Nevertheless some attempts have been made (e g., Tatsumi et al. 1986 Brenan et al. 1994, 1995 Keppler 1996 Ayers et al. 1998 Johnson and Plank 1999). 

Retard efficiently oxidation of polymers catalysed by metal impurities. Function by chelation. Effective metal deactivators are complexing agents which have the ability to co-ordinate the vacant orbitals of transition metal ions to their maximum co-ordination number and thus inhibit co-ordination of hydroperoxides to metal ions. Main use of stabilisation against metal-catalysed oxidation is in wire and cable applications where hydrocarbon materials are in contact with metallic compounds, e.g. copper. 

Hydrolysis increases the terpolymer limiting viscosity number in water by a factor of up to 45. Other previously published data(66-68) show that these terpolymers are nonnewtonian viscosifiers, metal-ion complexing agents, and effective flocculators. These materials are still "small" molecules in aqueous solution, however, and do not function as effectively when used 1. as nonnewtonian viscosifiers or 2. drag reducing agents as do poly(l-amidoethylene-co-(sodium 1-carboxylatoethylene)) copolymers. 

The action of carbon monoxide (CO) upon solutions of copper salts leads to the formation of cuprous CO complexes that have pronounced activity as reducing agents ... 

C8H7CI2NO2 3 5 -Dichloro-2 -hydroxy-acetophenone oxime Complexing agent Extraction-photomehic Gravimetric Photomehic Be, Cd, Co, Mn, Ni, U, V, Zn Co, V Pd Mn, U 3... 

C14H21JN3U3N 1 - Pheny Ipropanone-1 - pentylsulfonylhydrazone-2- oxime Complexing agent Cd, Co, Cu, Ni, Pb 59... 

C8H7NO3 2-Oxo-4 -hydroxyphenyl- acetaldehyde oxime Complexing agent Extraction-photometric Co, Ni, Pd Pd 81, 82... 

C10H7NO2 1,2-Naphthoquinone 1-oxime (l-NiUoso-2-naphthol) Complexing agent Extiaction-photometiic Gravimetric Separation Transition and rare eartii metals Co, Fe, Mo, U Co U 3... 

C10H7NO2 1,2-Naphthoquinone 2-oxime (2-NiUoso-1 -naphthol) Complexing agent Extiaction-photometric Transition metals Co, Ni, Pd, Ru 3... 

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