Cuprous chloride (CuCl) is extensively used as a catalyst in organic synthesis, and as a desulfurising, decolourising and deodorising agent in the petroleum industry. The traditional synthesis of CuCl nanocrystal powders, which has already caused a big problem in the environment, was via reducing copper(II) by using different additives and a quantity of concentrated acid. In this paper, we report an ecologically and environmental friendly route to prepare nanocrystalline CuCl powders, simply by using the CuCl2 and copper powders in a deep eutectic solvent (DES) at room temperature. The obtained CuCl nanocrystals were characterised by XRD, SEM and XPS techniques, and a possible formation mechanism was also proposed.
Acetylacetonato group-bearing poly(ethylene-co-propene-co-1 ,Chmdiene) (EPDM) was prepared and its chelate by crosslinking reaction with ferric salts. The hydroiodination of residual double bonds in the EPDM terpolymer under phase-transfer conditions and the substitution of iodine atoms in the hydroiodinated EPDM by acetylacetonato groups were studied. The ligand exchange reactions of acetylacetone with ferric trifluoromethanesulfonate (Fe(TFS)3) or ferric chloride in THF were explored by UVNis spectroscopy to find optimum conditions for the formation of the chelate complex ferric acetylacetonate. The results indicate that these two ligand exchange reactions are equilibrium reactions, and the addition of an organic base such as triethylamine can make the reactions go to completion. The character of the anion in the ferric salts has a significant effect on the ligand exchange reactions, which may be attributed to the different dissociation tendency of Fe-X bonds. The ligand exchange reactions in the polymer systems were studied, and Fe(II1)-chelate complex crosslinked EPDM elastogels with gel fractions higher than 90% were prepared. The mechanism of the chelate complex formation in the polymer systems is similar to that in model compound systems.
IntroductionA variety of theoretical models has been proposed to describe the relation between the modulus of an elastomeric material and the number-average molecular weight between crosslinks ac 1-4). However, there are considerable deviations of experimental results from theoretical predictions. The lack of unambiguous analytical procedures to determine crosslink density could be a source of these discrepancies. Recently, progress in better understanding of rubber-like elasticity has been made by using model polymer networks 5-6). Novel chelate-crosslinked model polymer networks have drawn more attention in this field7-''). Networks from polystyrene, poly(styrene-co-butadiene), poly(styrene-co-isoprene) as well as poly (dimethylsi1oxane) crosslinked by chelating with various transition metal ions have been prepared. Metal acetylacetonato') (acac) chelate complexes were chosen as crosslinks for several important reasons: (1) lfansition metal acetylacetonate chelates have high stability constants, and polymer networks of different structure can be prepared with use of different metal ions. (2) The strong and characteristic UV absorptions of acetylacetonato groups and metal acetylacetonates facilitate the quantitative determination of the number of acac ligands attached to the polymers and the number of crosslinks in polymer-metal chelate complexes. (3) Other spectroscopic methods, such as ESR and MOssbauer spectroscopy, are ' ) Acetylacetone = 2.4-pentanedione (acacH).
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