EDTA methods of production
Industrial production method of production of EDTA are mainly chlorine acetic acid method, cyanide hydrogen, sodium cyanide method 3 kinds of chloroacetic acid method is by reaction of ethylene diamine and sodium chloroacetate by acidification to. Chlorine acetic acid ratio of raw materials (kg / T): chloroacetic acid (95%), 2000, caustic soda (industrial) 880, ethylenediamine (70%) 290 hydrochloride (35%) 2500 (if sulfuric acid instead of hydrochloric acid, sulfuric acid (98%) 1200kg] production of major equipment: salt pan, condensation reaction tank, acidification pot, pot washing, centrifuge, storage tank, drying box operation process: in 800L stainless steel condensation reaction tank, 100kg of chloroacetic acid, 100kg ice and 135 kg 30% sodium hydroxide solution is added, under stirring add 18kg 83% ~ 84% of ethylenediamine. After 15 DEG C for 1 h, to every 10L batch addition of 30% sodium hydroxide solution, every time after accession to be phenolphthalein indicator not show alkaline add next batch, finally the reactant is alkaline. After 12h at room temperature, heating to 90 C, and activated carbon, filter, filter slag with water, and the final solution with a total volume of about 600L. With concentrated hydrochloric acid to pH no less than 3, precipitation crystallization. Filtered, washed to no chlorine root reaction. Drying, EDTA64kg. Yield 95%. Can also be carried out at high temperature. For example, using the following molar ratio: ethylenediamine: chloroacetic acid, sodium hydroxide = 1: 4.8: 4.8, reaction temperature for 50 DEG C, reaction time 6h, then boil 2 hours, the reaction product of acidified with hydrochloric acid can be obtained crystalline EDTA, the yield of 82% ~ 90%. Quality indexes: content is greater than or equal to 90%, iron (FE) is less than or equal to 0.01%; residue on ignition is less than or equal to 0.15%, heavy metals (PB) is less than or equal to 0.001%. In Na2CO3 solubility qualified: sodium cyanide is with ethylenediamine, sodium cyanide and formaldehyde as raw materials, in alkaline conditions reaction in one step synthesis of edta-4na, again with sulfuric acid edta-4na mother liquor control pH value of the solution, edta-2na or EDTA products. Further reaction with EDTA-2Na and sodium hydroxide to get EDTA-4Na product. % of >99, EDTA, EDTA, EDTA, sodium cyanide production is relatively advanced process route and chloroacetic acid, hydrogen cyanide method has the following advantages: (1) the main reaction in alkaline condition, the reaction process does not produce hydrogen cyanide production operation is safe; 2) reaction is at atmospheric pressure, the equipment material requirements are not high, so the equipment cost is low; (3) the production process does not emit toxic substances of waste, and easy processing; (4) with sodium cyanide production products, the device operation flexibility, according to the market demand regulation, edta-2na edta-4na ratio; (5) sodium cyanide production of EDTA and its sodium salt, the purity of the product yield > 90 percent.