Acetates, CH3COO

35 ACETATES, CH3COO Solubility All normal acetates, with the exception of silver and mercury(I) acetates which are sparingly soluble, are readily soluble in water. Some basic acetates, e.g. those of iron, aluminium, and chromium, are insoluble in water. The free acid, CH2COOH, is a colourless liquid with a pungent odour, boiling point 117°, melting point 17° and is miscible with water in all proportions it has a corrosive action on the skin. 

To study these reactions use a 2m solution of sodium acetate CH3COONa.3H20. 

Dilute sulphuric acid acetic acid, easily recognized by its vinegar-like odour, is evolved on warming. 

Concentrated sulphuric acid acetic acid is evolved on heating, together with sulphur dioxide, the latter tending to mask the penetrating odour of the concentrated acetic acid vapour. The test with dilute sulphuric acid, in which the acetic acid vapour is diluted with steam, is therefore to be preferred as a test for an acetate. 

CH3C00Na + H2S04 - CH3COOH+Na+ + HSO CH3COOH+C2H5OH - ch3coo.c2h5t + h2o 

Solubility all normal acetates, with the exception of silver and mercury(I) acetates which are sparingly soluble, are readily soluble in water. Some 

It is preferable to use amyl alcohol because the odour of the resulting amyl acetate is more readily distinguished from the alcohol itself than is the case with ethanol. It is as well to run a parallel test with a known acetate and to compare the odours of the two products. 

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The acetic acid reacts as an acid, giving up its proton, to form acetate, CH3COO-, a substance that can act as a base. We can write (50) in a general form ... 

Fatty acids are carboxylic acids, often with a long aliphatic tail (long carbon chains), which can be either saturated (all single bonds) or unsaturated. They are biosynthesized from two-carbon units (acetate, CH3COO ), and therefore usually have an even number of carbons with a range of C4 to C36, although Ci6 and Ci8 are dominant. Figure 7.7 shows the structure of octadecanoic acid (slearic acid, Ci8 o), c/.v-9-octadeccnoic acid (oleic acid, Ci8 i), and... 

All salts containing nitrate (NOj), acetate (CH3COO-), and perchlorate (C104 ) are soluble. 

Reactions with organic acids such as acetic or propionic acid yields zinc acetate, (CH3COO)2Zn, or zinc propionate, (CH3CH2COO)2Zn, upon concentration. 

Figure 8.2 Heroin is a derivative of morphine, it can be manufactured syntheticaiiy by repiacing the two hydroxyi (OH) groups in morphine with two acetate (CH3COO) groups thus, an aiternate name for heroin is diacetyimorphine.

This local adsorption geometry for formate on Cu(100) and Cu(110), with the molecular plane perpendicular to the surface and bonding through the two carboxylate atoms in near-atop sites, is also seen in other simple carboxylate species adsorbed on Cu(110), notably acetate (CH3COO—) [103] and benzoate (CgFIjCOO—) [104] formed, respectively, by exposure to acetic acid and benzoic acid. Relatively recent X-ray spectroscopy measurements combined with theoretical calculations provide further information on the bonding of formate and acetate on Cu(110) [105]. 

Sulfuric acid, dilute Acetates, CH3COO- Evolution of acetic acid (vinegar-like odor) concentrated sulfuric acid also evolves sulfur dioxide under mild heating... 

PH is a measure of the concentration of H+ in a solution. An acid is a proton donor, a base is a proton acceptor. Ionization of an acid yields its conjugate base, and the two are termed a conjugate acid-base pair, for example acetic acid (CH3COOH) and acetate (CH3COO ). The pK of an acid is the pH at which it is half dissociated. The Henderson-Hasselbach equation expresses the relationship between pH, ptC and the ratio of acid to base, and can be used to calculate these values. 

In solution, the tin acetates CH3COO(CH2)nSnCl3(n = 3-5)110 exist as a mixture of a monomer with intramolecular coordination (Section VILA) and an oligomer with intermolecular coordination in fast equilibrium on the 1H, 13C and 119Sn NMR time... 

In silver acetate (CH3COO Ag+) two strong absorption bands are found at... 

Carboxylic acids. Aliphatic carboxylic acids (R—GOOH) are deprotonated at physiological pH (pH 7) and are therefore represented as R—COO. Thus, acetic acid (GHj—COOH) exists as acetate (CH3COO ) at pH 7. A variety of short chain mono-, di-and tricarboxylic acids are important intermediates in metabolism and may be present at low concentrations in all cells either as the acid or as a covalent adduct. Thus, acetate (C2) and malonate (C3) can exist as the key acyl-coenzyme A thioester intermediates acetylGoA and malonylCoA, respectively. Phosphoenolpyruvate (C3), 1,3-bisphosphoglyceric acid (C3) and 3-phosphoglyc,erate (C3) are key metabolic intermediates. 

Methyl acetate, CH3COO.CH3. The commercial solvent is a liquid with a pleasant odour. It has a density of 0-93 g cm-3. 

With acetate (CH3COO"0, however, two resonance structures can be drawn. 

Reaction of bromomethane (CH3Br) with the nucleophile acetate (CH3COO") affords the substitution product methyl acetate with loss of Br as the leaving group (Equation [1]). Kinetic data show that the reaction rate depends on the concentration of both reactants that is, the rate equation is second order. This suggests a bimolecular reaction with a one-step mechanism in which the C-X bond is broken as the C—Nu bond is formed. 

Metal Albuminates.—Salts of certain metals, e.g., mercuric chloride, HgCh, and lead acetate, (CH3COO)2Pb. precipitate albumins from solution in the form of insoluble metal albuminates. These reactions are the basis for the use of white of egg as an antidote for poisoning with mercuric chloride. 

All nitrates (NO j) and most ethanoates, (acetates, CH3COO ) are soluble. 

Acetate, CH3COO- Carbonate, C03 Arsenate, As04 Hexacyanoferrate(ll),... 

Acetate CH3COO Carbonate C032 Phosphate po43... 

Answer Since the electrophile is soft and the solvent is protic, the softness of the nucleophile must be considered. Beeause sulfur is softer than oxygen, the softest and most nucleophilic is PhS, thiophenoxide. The remaining oxygen anions are then ranked by basicity Phenoxide (PhO ), p abH = 10, is more basic than acetate (CH3COO ), at 4.8. Therefore the next best nucleophile is phenoxide, and the least is acetate. 

The common nitrates, N03 acetates, CH3COO chlorates, C103 and perchlorates, CIO, are soluble in water. 

Note that the deprotonated product of the dissociation reaction is referred to as a conjugate base. For example, acetic acid (CH3COOH) dissociates to form the conjugate base acetate (CH3COO ). 

Carboxylic Acids Both formic and acetic acid dissociate at room temperature and below on (100) terraces giving surface hydroxide and the formate (HCOO-) and acetate (CH3COO-) species (Peng and Barteau, 1991). 

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