Copper acetate, decomposition

The majority of preparative methods which have been used for obtaining cyclopropane derivatives involve carbene addition to an olefmic bond, if acetylenes are used in the reaction, cyclopropenes are obtained. Heteroatom-substituted or vinyl cydopropanes come from alkenyl bromides or enol acetates (A. de Meijere, 1979 E. J. Corey, 1975 B E. Wenkert, 1970 A). The carbenes needed for cyclopropane syntheses can be obtained in situ by a-elimination of hydrogen halides with strong bases (R. Kdstcr, 1971 E.J. Corey, 1975 B), by copper catalyzed decomposition of diazo compounds (E. Wenkert, 1970 A S.D. Burke, 1979 N.J. Turro, 1966), or by reductive elimination of iodine from gem-diiodides (J. Nishimura, 1969 D. Wen-disch, 1971 J.M. Denis, 1972 H.E. Simmons, 1973 C. Girard, 1974),... 

The copper-catalyzed decomposition of diazoacetic ester in the presence of pyrrole was first described in 1899 and later investigated in more detail by Nenitzescu and Solomonica. Ethyl pyrrole-2-acetate (13), the normal product of electrophilic substitution, was obtained in 50% yield and was degraded to 2-methylpyrrole. Similarly iV -methylpyrrole with two moles of diazoacetic ester gave, after hydrolysis, the 2,5-diacetic acid (14) while 2,3,5-trimethylpyrrole gave, after degradation, 2,3,4,5-tetramethylpyrrole by substitution of ethoxycarbonylcarbene at the less favored )3-position. Nenitzescu and Solomonica also successfully treated pyrroles with phenyl-... 

Interestingly, the Fischer indole synthesis does not easily proceed from acetaldehyde to afford indole. Usually, indole-2-carboxylic acid is prepared from phenylhydrazine with a pyruvate ester followed by hydrolysis. Traditional methods for decarboxylation of indole-2-carboxylic acid to form indole are not environmentally benign. They include pyrolysis or heating with copper-bronze powder, copper(I) chloride, copper chromite, copper acetate or copper(II) oxide, in for example, heat-transfer oils, glycerol, quinoline or 2-benzylpyridine. Decomposition of the product during lengthy thermolysis or purification affects the yields. 

Thermal decomposition of metal acetates in the presence of PVP was proposed by Bradley et al. (30), where the preparative procedure of Esumi et al. (31) was modified. Thus, heating of palladium and copper acetates in a solvent with a high boiling point (ethoxyethanol) provides PVP-stabilized Pd/Cu bimetallic nanoparticles. In this method, not only thermal decomposition but also reduction by ethoxyethanol could be involved. However, the Bradley method can provide Cu/Pd bimetallic nanoparticles that contain less than 50 mol% of Cu, while our method mentioned earlier can provide fine particles with 80 mol% of Cu. In Esumi s original procedure, methyl iso-butyl ketone (MIBK) was used as a solvent without a stabilizer. In his method, Cu" was not completely reduced to Cu°, but Cu20 was involved in the bimetallic nanoparticles. Probably, thanks to Cu1 species in the surface of the particles, no stabilizer is necessary for the stable dispersion. 

Peracetic acid decomposition kinetics in the presence of cobalt or copper acetates were studied in the same apparatus used for the manganese-catalyzed reaction. However, in these studies it was used as a batch reaction system. The reactor was charged with peracetic acid (ca. 0.5M in acetic acid) and allowed to reach the desired temperature. At this time the catalyst (in acetic acid) was added. Samples were withdrawn and quenched with potassium iodide at measured time intervals. 

The copper-catalyzed decomposition of ethyl diazoacetate in the presence of a ketene acetal also leads to the corresponding cyclopropane in addition to larger quantities of diethyl maleate and diethyl fumarate ]f p-unsubstituted or... 

Research on the chemical properties of humic substances was extended by the Swedish investigator Berzelius (1839). One of his main contributions was the isolation of two light-yellow-colored humic substances from mineral waters and a slimy mud rich in iron oxides. They were obtained from the mud by extraction with base (KOH), which was then treated with acetic acid containing copper acetate. A brown precipitate was obtained ctilled copper apocrenate. When the extract was neutralized, another precipitate was obtained, called copper crenate. The free acids, apocrenic and crenic acids, were then brought into solution by decomposition of the copper complexes with alkali. These newly described humic substances were examined in considerable detail, including isolation, elementary composition, and properties of their metal complexes (Al, Fe, Cu, Pb, Mn, etc). 

Whereas the cobalt and manganese salts actually catalyze the oxidation, the effect of copper acetate essentially involves the decomposition of this complex to acetic add. The reaction takes place in slightly different conditions, depending on the type of oxidant employed. They can be summarized as follows x... 

ACETIC ACID, COBALT(II) SALT (71-48-7) Co(CjH30j)i 4HOH Noncombustible solid. Solution in water is basic (pH 6.8 to >7.0) reacts with acids. Some cobalt compounds react with oxidizers, acetylene. Cobalt is a known animal carcinogen. ACETIC ACID, CUPRIC SALT (142-71-2) Cu(C2H302)i H20 Noncombustible solid. Solution in water is basic reacts with acids. Incompatible with acetylides, hydrazine, nitromethane, mercurous chloride nitrates, sodium hypobromite. Thermal decomposition releases fumes of copper, acetic acid, and carbon oxides. 

CUPRIC DIACETATE (142-71-2) Cu(CjH30i)j Hj0 Noncombustible solid. Solution in water is basic reacts with acids. Incompatible with acetylides, hydrazine, nitromethane, mercurous chloride nitrates, sodium hypobromite. Thermal decomposition releases fiimes of copper, acetic acid, and carbon oxides. 

Copper-catalyzed decomposition of benzenesulfonyl azide in the presence of cyclohexene was the first reported evidence of a metal-catalyzed nitrene insertion reaction [25]. This seminal discovery was then followed by the pioneering work of Breslow and Gellman who introduced the use of iminoiodinanes as metal nitrene precursors as well as rhodium dimer complexes as catalysts [26,27]. They showed the formation of the corresponding benzosultam in 86% yield in the presence of rhodium (II) acetate dimer (Rh2(OAc)4) via an intramolecular metal nitrene C—H bond insertion reaction (Eq. (5.1)). 

Although in the dry state carbon tetrachloride may be stored indefinitely in contact with some metal surfaces, its decomposition upon contact with water or on heating in air makes it desirable, if not always necessary, to add a smaH quantity of stabHizer to the commercial product. A number of compounds have been claimed to be effective stabHizers for carbon tetrachloride, eg, alkyl cyanamides such as diethyl cyanamide (39), 0.34—1% diphenylamine (40), ethyl acetate to protect copper (41), up to 1% ethyl cyanide (42), fatty acid derivatives to protect aluminum (43), hexamethylenetetramine (44), resins and amines (45), thiocarbamide (46), and a ureide, ie, guanidine (47). 

Attempts to prepare the anhydrous nitrate by dehydration always fail because of decomposition to a basic nitrate or to the oxide, and it was previously thought that Cu(N03)2 could not exist. In fact it can be obtained by dissolving copper metal in a solution of N2O4 in ethyl acetate to produce Cu(N03)2.N204, and then driving off the N2O4 by heating this at 85-100°C. The observation by C. C. Addison... 

There have been relatively few detailed kinetic studies of the decompositions of metal acetates, which usually react to yield [1046] either metal oxide and acetone or metal and acetic acid (+C02 + H2 + C). Copper(II) acetate resembles the formate in producing a volatile intermediate [copper(I) acetate] [152,1046,1047]. 

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