Reductions copper® chloride

Wacker (1) A general process for oxidizing aliphatic hydrocarbons to aldehydes or ketones by the use of oxygen, catalyzed by an aqueous solution of mixed palladium and copper chlorides. Ethylene is thus oxidized to acetaldehyde. If the reaction is conducted in acetic acid, the product is vinyl acetate. The process can be operated with the catalyst in solution, or with the catalyst deposited on a support such as activated caibon. There has been a considerable amount of fundamental research on the reaction mechanism, which is believed to proceed by alternate oxidation and reduction of the palladium ... 

The previous examples involve reduction (hydrogenation) of organic molecules, but transition metal complexes can also catalyze oxidation. For example, the Wacker process, which has been widely used to convert ethylene to acetaldehyde, depends on catalysis by palladium(II) in the presence of copper(II) in aqueous HC1. The role of the copper chloride is to provide a means of using air to reoxidize the palladium to palladium(II). Once again, Zeise-type coordination of the ethylene to the metal center is believed to be involved ... 

Arsenic. — Introduce 20 gm. of arsenic-free, metallic zinc into the generating flask of a Marsh apparatus, and start the hydrogen by adding dilute (1 5) sulphuric acid. Dissolve 1 gm. of copper chloride in 20 cc. of water, introduce the solution in small quantities at a time into the Marsh apparatus, and maintain a slow stream of gas for about one hour. No deposit of arsenic should be visible in the reduction tube of the apparatus within this time. 

EMICl- [22, 37, 38, 51-54], and BMICI-AICI3 [55] ionic liquids. In the case of acidic ionic liquids, it is possible to introduce monovalent and divalent copper species, Cu(l) and Cu(II), by dissolving copper chloride and dichloride, respectively, and by the anodic dissolution of metallic copper. Metallic Cu can be obtained by the reduction of Cu(I). The formal potentials of Cu(I)/Cu in an acidic MPCl-BPC1-, EMICI-AICI3 are reported as 0.777 [49], 0.784 [50], and 0.837 [52] V, respectively. Cu(I) can be also obtained by the reduction of Cu(II), of which the formal potentials in the acidic MPCl- and BPCI-AICI3 are reported as 1.851... 

The electrodeposition copper, Cu, has been investigated in an acidic EMICl— ZnCl2 ionic liquid [91]. A monovalent copper species, Cu(l), is introduced by dissolving copper chloride, CuCl, or the anodic dissolution of Cu metal. The electrodeposition of metallic cupper is possible by the reduction of Cu(I) at 0.5 0.6 V vs. Zn/Zn(II). The formation of Zn-Cu alloys was also reported. 

Incorporation of copper chloride in about 10% of the molar quantity of nickel before the borohydride reduction step further improved the selectivity of the Ni(B) catalysts. Copper improves the selectivity of Raney nickel catalysts in phenylacetylene semihydrogenation but not to the extent obtained using the copper-modified Ni(B) catalysts. The Cu-Ni(B) catalysts were more selective than the Cu(B) catalysts prepared by the borohydride reduction of copper chloride. Adding zinc or iron salts to a Ni(B) catalyst had only a slight effect on phenylacetylene semihydrogenation selectivity. ... 

The activation and functionalization of C-H bonds by the Pt" ion is particularly attractive because of the unusual regioselectivity, high oxidation level specificity, and mildness of reaction conditions. Moreover, Sen has recently reported that, in the presence of copper chloride at 120-160 °C, Shilov chemistry can be made catalytic with dioxygen as the ultimate oxidant [39]. A number of aliphatic acids were tested, and turnover numbers of up to 15/hour with respect to platinum were observed. H/D exchange studies also confirm the marked preference for the activation of primary C-H bonds in the presence of weaker secondary C-H bonds. This study constituted the first example of the direct use of dioxygen in the catalytic oxidation of unactivated primary C-H bonds under mild conditions that does not involve the use of a co-reductant (e. g., sacrificial metals, 2H + 2e", dihydrogen, or carbon monoxide see below). 

The above DMC synthesis using MN was discovered at UBE, and a plant based on this technology has recently gone onstream with a capacity of about 6000ton/yr. Reaction (7) is catalyzed by supported palladium(II) halide complexes, which allow high (90-95%) CO selectivity. The addition of a cocatalyst such as copper chloride is required to prevent the reduction of Pd(II) to Pd(0) because Pd(0) tends to accelerate the formation of DM0. 

This nickel catalyst can be further optimized by the addition of copper chloride before the hydride reduction step leading to improvements in alkene selectivity [17] ... 

Note the particularly mild reaction conditions and the fact that the reaction depicted by Eq. (6) progresses without cleavage of the allylic hydroxyl group. These copper-modified nickel catalysts were found to be more selective than the analogous Cu(B) formulations derived from borohydride reduction of copper chloride [17]. Copper modification of Raney nickel has also been shown to benefit the selectivity of phenylacetylene hydrogenation, but not to the same extent as the Cu-Ni(B) catalyst. 

Lithium chloride, Uthiurn bromide, and copper chloride were foimd to be effective in reducing the melting temperature of polyamides. The reduction of the melting temperature of Nylon 6 by the addition of lithium chloride is shown in Table 5.8. 

When a freshly sanded strip of aluminum is dipped into an aqueous solution of copper chloride, CuCl2(ay), it starts to dissolve and some brown metallic copper is formed on the strip. Use standard reduction potentials (see Table 12.2) to demonstrate that this reaction is spontaneous under standard-state conditions. Why must the aluminum be freshly sanded ... 

On the other hand, analogous reaction with Cu(ll) salts led to cross-linked structures. Reduction of Cu(ll) to the monovalent state occurred with formation of sulfur and carbonyl sulfide. The copper polymer could also be obtained from aqueous ammoniacal copper chloride. 

Copper Chloride 10 23 6 Little or no attack some absorption and slight reduction in mechanical property Nylon 1000 Hoechst Celanese... 

For the MOF [Cu2(bpdc)2(dpq)2(H20)]-H20 obtained from the hydrothermal reaction of copper chloride with the mixed ligands bpdc and dpq, the redox couple observed at -100/-l-50mV versus SCE in pH 2 (phosphate buffer) was attributed to Cu /Cu . The charge below the reduction peak was much larger than that below the oxidation peak, possibly due to the instability of the reduced form of copper, which may undergo a fast chemical oxidation in an aqueous solution of pH 2. 

Oxidation Processes. These processes convert mercaptans into less odoriferous disulfides by such processes as the doctor, copper chloride, hypochlorite, and lead sulfide, processes. Since disulfides harm the lead susceptibility of gasoline and since the need of reduction of mercaptans to doctor sweet (0.0004 per cent) is being questioned, these processes are being gradually abandoned. However, catalysts or inhibitors of the 7>-phenylenediamine type, which in the presence of air cause mercaptans in some caustic-washed gasolines to be converted during a few days into disulfides (so-called inhibitor sweetening), continue to be used because of the cheapness of such a process. Small amounts of... 

By the reduction of copper(II) chloride or a mixed solution of copper(II) sulphate and common salt by sulphur dioxide. 

Trimethylene dibromide (Section 111,35) is easily prepared from commercial trimethj lene glycol, whilst hexamethylene dibromide (1 O dibromohexane) is obtained by the red P - Br reaction upon the glycol 1 6-hexanediol is prepared by the reduction of diethyl adipate (sodium and alcohol lithium aluminium hydride or copper-chromium oxide and hydrogen under pressure). Penta-methylene dibromide (1 5-dibromopentane) is readily produced by the red P-Brj method from the commercially available 1 5 pentanediol or tetra-hydropyran (Section 111,37). Pentamethylene dibromide is also formed by the action of phosphorus pentabromide upon benzoyl piperidine (I) (from benzoyl chloride and piperidine) ... 

The special reducing agent (a solution containing cupro-ammonia ions) is first prepared. Dissolve 63 g. of crystallised copper sulphate in 250 ml. of water in a 1-Utre heaker, add 100 ml. of concentrated ammonium hydroxide solution (sp. gr. 0-88), and cool the solution to 10°. Dissolve 17 8 g. of hydroxylammonium chloride or 21 g. of hydroxylammonium sulphate in 60 ml. of water, cool to 10°, and add 42 -5 ml. of QN sodium hydroxide solution if the resulting solution of tydroxylamine is not clear, filter it at the pump. Without delay add the hydroxylamine solution, with stirring, to the ammoniacal cupric sulphate solution. Reduction occurs at once, a gas is evolved, and the solution assumes a pale blue colour. Protect the reducing agent from the air if it is not used immediately. 

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