Silver maleate

Let us suppose it is desired to calculate the theoretical yield of ethyl maleate when 33 g. of silver maleate, suspended m dry ether, are treated with the calculated quantity of ethyl iodide (31-2 g.). 

From the equation representing the chemical reaction involved, it is evident that 330 g. of silver maleate will theoretically react with 312 g. of ethyl iodide in ethereal solution to produce 172 g. of ethyl maleate. It follows, therefore, that 33 g. (0 1 mol) of silver maleate will react with 31-2 g. (0 2 mol) of ethyl iodide to give a theoretical yield of 17 2 g. (0-1 mol) of ethyl maleate. In practice, the actual yield found for these quantities is of the order of 16 0 g. the percentage yield is therefore (16 0/17-2) X 100 = 93 per cent. 

Preparation of silver maleate. Dissolve 65 g. of pure maleic acid (Section 111,143) in the calculated quantity of carefully standardised 3-5N aqueous ammonia solution in a 1-htre beaker and add, whilst stirring mechanically, a solution of 204 g. of silver nitrate in 200 ml. of water. Filter oflf the precipitated silver maleate at the pump, wash it with distilled water, and press well with the back of a large flat glass stopper. Dry in an electric oven at 50-60° to constant weight. The yield of the dry silver salt is 150 g. Store in a vacuum desiccator in the dark. 

Ethyl fumarate has been prepared from fumaric acid and ethyl alcohol, with or without sulfuric acid as catalyst,4 from silver fumarate and ethyl iodide,5 from silver maleate and ethyl iodide plus a trace of iodine,6 from ethyl maleate by the action of iodine,6 from ethyl maleate and phosphorus pentachloride,7 and by passing hydrogen chloride into a boiling absolute alcohol solution of malic acid.8... 

Silicone, fluids, 59, 1020 resins, 1020 stopcock greases, 225 Silver maleate, 388 Silver nitrite, 201 Simon s test, 421 ... 

Mohamed et al. [129] have reported non-isothermal studies of the decompositions of silver maleate and fumarate. Following some initial sublimation, both salts reacted to form maleic anhydride and CO as dominant products, together with other organic compounds. The decomposition of silver maleate commenced at 443 K and the anion isomerized to fumarate at 518 K which decomposed at 557 K. The main decomposition of silver fumarate occurred at 566 K. 

This polymer has also been obtained by reacting silver maleate with ethylene dibromide [2]. 

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