Metal acetates

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]. 

Isothermal a—time curves for the decomposition of U02(CH3C02)2 in air (513—573 K) [1018] showed two approximately linear regions, 0.0 a 0.2 and 0.2 a 0.9, for which the values of E were 107 and 165 kJ mole-1, respectively. In nitrogen, the earlier portion of the curve was not linear and E = 151 kJ mole-1 for the later interval. The zero-order kinetic behaviour was explained by growth of nuclei in thin, plate-like crystals, which were shown by microscopic and surface area measurements to fragment when a 0.85. The proposed initial step in the decomposition was fission of bonds between the U02+ and the (OCO CH3) species [1018]. 

Barium acetate decomposes [1050] with growth of planar product nuclei, E = 167 kJ mole-1 (720—750 K). Reactions of other Group II acetates are reported [1051] as being accompanied by at least partial melting. 

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Alkynyl anions are more stable = 22) than the more saturated alkyl or alkenyl anions (p/Tj = 40-45). They may be obtained directly from terminal acetylenes by treatment with strong base, e.g. sodium amide (pA, of NH 35). Frequently magnesium acetylides are made in proton-metal exchange reactions with more reactive Grignard reagents. Copper and mercury acetylides are formed directly from the corresponding metal acetates and acetylenes under neutral conditions (G.E. Coates, 1977 R.P. Houghton, 1979). 

Theophrastos (272—287 Bc) studied the utilisation of acetic acid to make white lead and verdigris [52503-64-7]. Acetic acid was also weU-known to alchemists of the Renaissance. Andreas Libavius (ad 1540—1600) distinguished the properties of vinegar from those of icelike (glacial) acetic acid obtained by dry distillation of copper acetate or similar heavy metal acetates. Numerous attempts to prepare glacial acetic acid by distillation of vinegar proved to be in vain, however. 

Potassium acetate, mbidium acetate, and cesium acetate are very soluble ia anhydride ia contrast to the only slightly soluble sodium salt. Barium forms the only soluble alkaline earth acetate. Heavy metal acetates are poorly soluble. 

Acetone was originally observed about 1595 as a product of the distillation of sugar of lead (lead acetate). In the nineteenth century it was obtained by the destmctive distillation of metal acetates, wood, and carbohydrates with lime, and pyrolysis of citric acid. Its composition was determined by Liebig and Dumas in 1832. 

Other possibilities are the reduction of nitro groups by applying the sample solutions to adsorbent layers containing zinc dust and then exposing to hydrochloric acid vapors [110] 3,5-Dinitrobenzoates and 2,4-dinitrophenylhydrazones can also be reduced in the same way on tin-containing silica gel phases [111] Cellulose layers are also suitable for such reactions [112] Seiler and Rothweiler have described a method of trans-salting the alkali metal sulfates to alkali metal acetates [113]... 

Metal-free phthalocyanines can also be transferred into the metal phthalocyanines (e.g., PcCu, PcZn, PcNi) by treatment with the respective metal acetates in penlan-l-ol.290... 

Reactions in acetic anhydride with metal acetates present probably occur by 1,4-addition of bromonium acetate (85CHE458). When NBS in sulfuric acid at 20°C was used, the product ratio resembled that observed with bromine-sulfuric acid-silver sulfate. At 60°C the ratio changed to 2 1.2 1 as a consequence of more extensive dibromination (88CHE892) (Scheme 33). As might have been deduced, 2-(2 -thienyl)quinoline was brominated only in the thiophene ring (82CHE28). 

On the other hand, Sb203 and metal oxides such as Ge02 exhibit a good catalytic activity for the polycondensation step. This explains why the associations of metal acetates with Sb203 are often reported catalytic systems. The following order in catalytic activity was found for the PEN polycondensation step Ti(IV)... 

Neutral PET hydrolysis usually takes place under high temperature and pressure in die presence of alkali metal acetate transesterification catalysts.28 It is diought diat the catalytic effect observed on the part of zinc salts is the result of electrolytic changes induced in die polymer-water interface during the hydrolysis process. The catalytic effect of zinc and sodium acetates is thought to be due to die destabilization of die polymer-water interface in the hydrolysis process. 

A proposed mechanism of PET glycolysis would be (1) glycol diffusion into die polymer (2) swelling of the polymer, which increases the rate of diffusion and (3) reaction (transesterification) of the glycol hydroxy group at an ester group in die polyester chain.24 Since it is a transesterification process, metal acetate salts are effective catalysts. 

Deprotonation of Group 4 mono(pentamethylcyclopentadienyl) metal acet-amidinates can be achieved in high yield using sterically encumbered bases (Scheme 103) to provide anionic enolate complexes as purple powders. These can subsequently be allowed to react with electrophiles (e.g., PhCH2Cl, CH2CI2, Me2SiCl2) to produce several new classes of metal amidinates that are not accessible by conventional routes (Scheme 104). ° ... 

Alkenes can also be oxidized with metallic acetates such as lead tetraacetate or thallium(III) acetate " to give bis-acetates of glycols. Oxidizing agents such as benzoquinone, Mn02, or 02, along with palladium acetate, have been used to convert conjugated dienes to l,4-diacetoxy-2-alkenes (1,4 addition). ... 

Acidification with trichloracetic acid catalyses oxidation , the fractional increase in the rate coefficient per mole of acid added, viz. Ak/ko)/[sicid], being of the order of two. Strong catalysis by alkali metal acetates has been observed for several oxidations, e.g. of m-cyclohexane-l,2-diol °, formic acid , methyl mannoside and galactoside and several a-hydroxycarboxylic acids °. 

M. Faraday was the first to observe an electrocatalytic process, in 1834, when he discovered that a new compound, ethane, is formed in the electrolysis of alkali metal acetates (this is probably the first example of electrochemical synthesis). This process was later named the Kolbe reaction, as Kolbe discovered in 1849 that this is a general phenomenon for fatty acids (except for formic acid) and their salts at higher concentrations. If these electrolytes are electrolysed with a platinum or irridium anode, oxygen evolution ceases in the potential interval between +2.1 and +2.2 V and a hydrocarbon is formed according to the equation... 

Photoactivity of Reagent Anatase Titanium Dioxide Coated with Metal Acetates... 

In addition, no DNA cleavage was observed with 19 under silver acetate activated conditions, also consistent with Nozaki s [78] observation that this metal acetate produced little of this dimerization product. The DNA cleavage observed with high concentrations of silver acetate and no cleavage with... 

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