Method for preparing stability modified amido polycarboxylic acid ferric ammonium

Abstract

The present invention provides a preparation method of the amino poly-carboxylic iron ammonium with the improved stability. The steps are as following: the solution of the matrix material is added into the deionized aqueous solution of the chelator pincer amino poly-carboxylic acid, wherein the molar ration between the matrix material and the amino poly-carboxylic acid is between 1.0 and 1.2; theferrous material is added in order, wherein theolar ration between the amino poly-carboxylic acid and Fe is between 1.01 and 1.10; the mixture is stirred strongly; the solution after the reaction is cooled; the solution with the matrix material is added so that the pH value is between 7 and 8; the solution is cooled, blown, diluted and filtered to get the product; the amino poly-carboxylic acid is selected from the ethylenediamine tetraacetic acid, the 1, 3-C diamine tetraacetic acid and so on; the matrix material is selected from the ammonia, anhydrous ammonia, sodium hydroxide and so on. And the ferrous material is selected from the oxide containing the iron, the iron powder, the iron salt and so on. The amino poly-carboxylic iron ammonium produced in the invention can significantly enhance the stability, reduce or avoid the formation of the dark particles. The days for the recession can reach more than 15 months at the room temperature.

Description

technical field [0001] The invention relates to a chemical process, in particular to a preparation method of amino polycarboxylate iron ammonium salt with improved stability. Background technique [0002] In the imaging industry, the oxidization of metallic silver or negative silver ions is known as bleaching. An ideal bleach would react quickly with silver and then react rapidly with air to regenerate the bleach. Iron compounds have been used for this purpose for a decade. The most commonly used iron compound is ethylenediaminetetra Ferric ammonium acetate, due to its desirable reducing properties and ease of preparation from inexpensive industrial chemicals such as ferric oxide, ethylenediaminetetraacetic acid (EDTA) and aqueous ammonia. [0003] According to Donovan and Surash (US Patent: 3,767,698 published on October 23, 1973), Svatek (US Patent: 4,364,871 published on October 21, 1982 and US Patent: 4,438,040 published on May 20, 1984) et al., EDTA The ferric ammoniu...

AI Technical Summary

Problems solved by technology

[0005] The product of example 2 and example 5 of U.S. Patent 5,898,078 is relatively stable (it decay days number is only greater than 20 days under the condition above 50 ℃), but chelate in the feeding ratio: the molar ratio of Fe is all less than 1, that is to say Fe 3 o 4 It is excessive, so on the one hand, it will put a lot of pressure on the filtration of the subsequent products

Chelate compound in the charging ratio of example 3 and example 4 in this patent: the molar ratio of Fe is 1.08 and 1.02 respectively, but product stability is not good (its decay days are only 5 days under the condition above 50 ℃)

U.S. Patent: Chelate in 4,364,871 and 4,438,040 feed ratio: the molar ratio of Fe is all greater than 1, but its product stability is bad equally