Copper complexes organic sulfides

Figure 4. Concentrations in a model of seawater chemistry including the copper sulfide reactions, a) n = 1 with Kj = 1010 and a value R - 10s for the ratio of organic copper complexes to Cu2+. b) n = 2 with K2 = 1020, R = 105.

To an ice-cold soln of lysine-Cu(II) complex 5 (5.2 g, 14.9 mmol see Section 2.1.2.2.1.1) in 1 M NaOH (60 mL) and MeOH (60 mL) was added ethyl formate (24 mL, 298 mmol), and the mixture was stirred vigorously for 2 h with ice-cooling. The pH was maintained between 8 and 9 by addition of 5 M NaOH. The organic solvent was removed, and the precipitated copper complex was filtered off and washed with several portions of H2O. The complex was suspended in H2O, H2S was passed through the solution and the copper sulfide was removed by filtration with the aid of Norite and Filter-cel. The filtrate was concentrated to a small volume, and EtOH was added to bring about crystallization. The crystals were collected, dissolved in a small volume of HjO and recrystallized by addition of EtOH yield 1.72 g (33%) mp 214-215 °C (dec) -Hl.l (c 0.91, H2O) -1-15.5 (c 1.4, sat. aq NaHCOs). 

Interpretation If the haze consists primarily of complexes of copper and organics, sediment is partially burnt. However, inorganic precipitates (copper sulfide and ferric phosphate) casse will not bum. 

If the haze in step 2 dissipates, copper is suspected. Centrifuge the suspect wine and collect sediment on a stainless steel laboratory spatula. Slowly dry the sediment over a Bunsen burner, and when completely dry, attempt to ignite by more intensive exposure to the flame. If the haze consists primarily of complexes of copper and organics, the sediment will partially burn. However, inorganic precipitates (copper sulfide and ferric phosphate) will not burn. 

Bonding Agents. These materials are generally only used in wire cable coat compounds. They are basically organic complexes of cobalt and cobalt—boron. In wire coat compounds they are used at very low levels of active cobalt to aid in the copper sulfide complex formation that is the primary adherance stmcture. The copper sulfide stmcture builds up at the brass mbber interface through copper in the brass and sulfur from the compound. The dendrites of copper sulfide formed entrap the polymer chains before the compound is vulcanized thus hoi ding the mbber firmly to the wire. 

In the presence of hydrogen sulfide produced by anaerobic bacterial activity, particularly sulfate reducers, conditions are created whereby sulfides of copper and zinc could be formed. The partition of these metals between the sulfide phase and the organic phase depends on the relation between the stability constants of the complexes and the solubility product of the sulfides of these metals. Elements with small solubility products of their sulfides and low stability constants of their chelates would be expected to go into the sulfide phase when hydrogen sulfide is present. Copper is typical of such elements. Chalcocite has a solubility product of about 10" ° and covellite about 10"44, whereas the most stable chelates of copper have stability constants of about 10" Consequently, copper could be expected to be accumulated as the sulfide. Zinc sulfide has a much larger solubility product however, the stability of its chelates is lower. From the fact that zinc appears to be completely associated with the inorganic fraction of coal, it can be assumed that the relation between the solubility product of any of its sulfides and its chelates favors formation of the sulfide. Iron could be expected to follow a similar pattern. 

The final step in the reaction involves demetallation of the organic product by H2S with the resultant loss of copper(n) sulfide. The reaction is not quite as simple as it appears, and the intermediate copper(n) complex which is demetallated is not of the expected... 

Figure 3. Rough ratios of equilibrium concentrations for inorganic (31.321 and organic (20-221 copper species to those of the aquo ion Cu2+, with sulfide complexes plotted as functions of free bisulfide ion level and set at the lower limit in Table II.

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