Patent GB-358113-A (GB)
Title: Process for the manufacture of complex salts of aromatic compounds
IPC: C07C309/41
Filed: 1930-07-05
Abstract: Metal-complex compounds yielding neutral solutions are obtained by the use of oxides or hydroxides of magnesium, calcium, or strontium as neutralizing basic substances in the formation by the customary methods of complex compounds of aromatic o-dihydroxy compounds containing acid salt-forming groups with metals, other than alkali or alkaline-earth metals, of atomic number equal to or greater than 22. According to one method the magnesium, calcium or strontium salt of the aromatic o-dihydroxy compound reacts with a salt, oxide or hydroxide of the complex-forming metal in presence of an alkali, or of a nitrogen base, or of a hydroxide of magnesium, calcium or strontium.  According to another method an alkali or nitrogen base salt of the aromatic o-dihydroxy compound reacts with a salt, oxide or hydroxide of the complex-forming metal and an oxide or hydroxide of magnesium, calcium or strontium is used for neutralization.  When either of the above methods is employed the oxides or hydroxides of magnesium, calcium or strontium may be replaced by mixtures of salts of these metals with corresponding quantities of alkali.  Specified aromatic o-dihydroxy compounds are the carboxylic and sulphonic acids of pyrocatechol and of its substitution products, such as pyrogallol, and of o-dihydroxynaphthalenes and o-dihydroxyanthracenes.  The following examples are specified: (1) An aqueous solution of calcium pyrocatecholdisulphonate (obtained from the acid and calcium chloride) is boiled with addition of a moist paste of antimony oxide and sufficient milk of lime to neutralize, the solution is filtered from excess of antimony oxide and the complex salt is obtained by concentrating the filtrate and stirring into methyl alcohol; the product is a colourless powder, its aqueous solution is isotonic to tissue and is suitable for injection in high concentration.  (2) The process of (1) is effected with use of caustic soda for the neutralization.  (3) An aqueous solution of sodium pyrocatecholdisulphonate with an addition of a moist paste of antimony oxide is neutralized while boiling with milk of lime, and the product is isolated as in (1); it has a lower calcium content than the products of (1) and (2).  (4) An aqueous solution of calcium pyrocatecholdisulphonate with an addition of freshly precipitated bismuth hydroxide paste is concentrated and stirred into methyl alcohol to precipitate the product as a yellow powder; its solution has an acid reaction and may be neutralized with dilute caustic soda, diethylamine, or milk of lime; solutions isotonic to tissue have a much higher concentration than solutions of the sodium salt.  (5) Cupric chloride is added to a hot aqueous solution of calcium pyrocatecholdisulphonate, milk of lime is added to neutralize, the solution is filtered, and the product is precipitated as a blue powder by stirring the filtrate into alcohol; it dissolves readily in water and the solution is neutral.  (6) A freshly prepared paste of antimonic acid is added gradually to a hot aqueous solution of sodium pyrocatecholdisulphonate, the solution is neutralized in the cold with milk of lime and filtered, and the product is precipitated from the filtrate by addition of methyl and ethyl alcohols; it is a whitish-grey powder of antimony (pentavalent)-calcium-sodium pyrocatecholdisulphonate, readily soluble in water, the solution being neutral.  (7) A freshly prepared paste of antimonic acid is added to a hot aqueous solution of sodium pyrogalloldisulphonate, the solution is neutralized in the cold with milk of lime, and the product is isolated as in (6); it has similar properties.  (8) Magnesia is gradually added to a solution containing sodium pyrocatecholdisulphonate and stannous chloride and when the solution is neutral or feebly alkaline, it is filtered and the product is precipitated by addition of methyl alcohol; the precipitate is washed with 90 per cent alcohol until free from chlorine and thereafter repeatedly reprecipitated from water-methyl alcohol-ethyl alcohol; it is a slightly coloured powder of tin-magnesium-sodium pyrocatecholdisulphonate, readily soluble in water to an almost neutral solution; the p  copper-magnesium-sodium pyrocatecholdisulphonate may be produced similarly.  (9) A suspension of freshly precipitated strontium hydroxide is gradually added to an aqueous solution containing sodium pyrocatecholdisulphonate, copper chloride and water and when the solution is neutral, it is filtered and the product is precipitated by stirring into methyl alcohol; the precipitate is washed with 90 per cent alcohol; it is a green powder of copper-strontium-sodium pyrocatecholdisulphonate, soluble in water to an almost neutral solution.  (10) An aqueous solution containing ferric chloride and potassium 2 : 3-dihydroxynaphthalene-6-sulphonate is neutralized with milk of lime and filtered, and the filtrate, after concentration, is stirred into alcohol to precipitate the iron-calcium-potassium salt as a dark red powder readily soluble in water, the solution being almost neutral.  (11) An aqueous solution containing ferric chloride and pyrocatechol-o-carboxylic acid is neutralized with milk of lime and filtered, and the filtrate is poured into dry ethyl alcohol to precipitate the iron-calcium pyrocatechol-o-carboxylic acid as a dark violet powder readily soluble in water, the solution being almost neutral.  (12) An aqueous solution of calcium pyrocatechol-calcium-sodium disulphonate (cf. Specification 351,971) is boiled with an addition of zinc oxide, and filtered and the filtrate is stirred into methyl alcohol to precipitate the calcium-sodium salt of zinc pyrocatecholdisulphonic acid as a white powder readily soluble in water, the solution being neutral.  (13) An aqueous solution containing calcium pyrocatechol-calcium-sodium disulphonate and cobaltous chloride is nuetralized with caustic soda lye, filtered, and stirred into methyl alcohol to precipitate the calcium-sodium salt of the cobalt pyrocatecholdisulphonic acid as a bluish-red powder, readily soluble in water, the solution being neutral. (14) An aqueous solution containing calcium pyrocatechol calcium-sodium disulphonate and copper chloride is neutralized with caustic soda lye, filtered and poured into alcohol and the precipitate of the calcium-sodium salt of copper pyrocatecholdisulphonic acid is washed with 90 per cent alcohol; it is a green powder soluble in water, the solution being neutral. (15) An aqueous paste of freshly precipitated copper hydroxide is mixed with an aqueous solution of calcium pyrocatechol-calcium-sodium disulphonate and the clear solution obtained is diluted with methyl alcohol and poured into ethyl alcohol to precipitate the copper calcium pyrocatechol-calcium-sodium disulphonate as a dark green powder readily soluble in water.  (16) An aqueos paste of freshly precipitated copper hydroxide is mixed with an aqueous solution of pyrocatechol-sodium disulphonate and the mixture is neutralized with milk of lime, filtered, and poured into a mixture of methyl and ethyl alcohols to precipitate the product as a green powder readily soluble in water, the solution being neutral; copper-calcium complex salts may also be produced by treating a mixture of pyrocatechol-sodium disulphonate and copper chloride with milk of lime or with calcium chloride and caustic soda lye. (17) Calcium pyrocatechol-calcium-sodium disulphonate and lead oxide are shaken with water and the solution is stirred into methyl alcohol to precipitate the product as a white powder readily soluble in water, the solution being almost neutral.  (18) Freshly precipitated bismuth hydroxide is added to an aqueous solution of calcium pyrocatechol-calcium-sodium disulphonate and the mixture is heated to obtain a clear solution which is stirred into methyl alcohol to precipitate the bismuth-calcium pyrocatechol-calcium-sodium disulphonate as a whitish powder, readily soluble in water.