CN1388113A - Production process of ethylene diamine tetraacetic acid and its salt with hydrocyanic acid synthesis gas as raw material - Google Patents
Production process of ethylene diamine tetraacetic acid and its salt with hydrocyanic acid synthesis gas as raw material Download PDFInfo
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- CN1388113A CN1388113A CN 02133458 CN02133458A CN1388113A CN 1388113 A CN1388113 A CN 1388113A CN 02133458 CN02133458 CN 02133458 CN 02133458 A CN02133458 A CN 02133458A CN 1388113 A CN1388113 A CN 1388113A
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Abstract
The present invention is the production process of ethylene diamine tetraacetic acid and its salt with coarse synthetic hydrocyanic acid gas as material. The technological process includes the steps of: mixing and reacting formaldehyde and ethylene diamine inside a reactor to synthesize aldehyde-amine mixture liquid; introducing synthetic hydrocyanic acid gas and reacting with aldehyde-amine mixture to produce intermediate product ethylene diamine diethyl cyanamide; introducing formaldehyde, acid and synthetic hydrocyanic acid gas to produce ethylene diamine tetraethyl cyanamide simultaneously; hydrolyzing ethylene diamine tetraethyl cyanamide with acid or alkali aqueous solution to produce ethylene diamine tetraacetic salt; and adding acid to regulate pH to 1-5 to obtain ethylene diamine tetraacetic acid and its salt.
Description
The technical field is as follows:
the invention relates to a method for producing ethylene diamine tetraacetic acid and salts by using hydrocyanic acid synthesized crude gas as a raw material.
Background art:
ethylenediamine tetraacetic acid (EDTA) is white, odorless, and crystalline powder. Melting point 240 deg.C (decomposition), insoluble in water, ethanol and common organic solvents, and easily soluble in sodium hydroxide, sodium carbonate and ammonia solution. The alkali metal salts thereof are soluble in water. EDTA and its salts include disodium EDTA, tetrasodium EDTA. It can also be used for producing zinc EDTA salt, calcium EDTA salt, magnesium EDTA salt, copper EDTA salt, ferric EDTA sodium salt, ferric EDTA ammonium salt, etc. EDTA and its salts can form a powerful ligand with various metal ions through two nitrogen atoms and four carboxyl groups, and can perform a complex reaction with various metal ions to form a compound with a stable cyclic structure, thereby effectively reducing or inhibiting side reactions or harmful effects caused by the metal ions. Because of its excellent chelating properties, EDTA and its salts are widely used in the fields of water treatment agents, detergents, metal cleaning, industrial cleaning, photographic chemicals, leather chemicals, paper making chemicals, oilfield chemicals, medicine, food, textile, chemical fiber, dye, synthetic resin, rubber industry, agricultural chemicals, and analytical inspection.
Documents CN98811975.7 and US6297397 describe reacting ethylenediamine, NaCN and an aqueous formaldehyde solution in the presence of a base to form a solution of EDTA-Na containing impurities; crystallizing the solution with a solvent to obtain EDTA-Na crystals; and recovering EDTA-4Na crystals, wherein the crystallization solvent is a mixture of methanol and a non-methanol alcohol, which is high in cost.
The synthesis of ethylenediamine tetraacetic acid from high-purity liquid hydrocyanic acid, ethylenediamine and formaldehyde is described in GB871380, JP55151537 and Sichuan chemical industry (1987, 3). High-purity liquid hydrocyanic acid has high cost and poor safety.
The Guangzhou food industry science and technology (1999.15(1), 15-46), the economic and technical information of fine chemistry (1995(1), 8-9), the Zhejiang chemical industry (1988, (6), 25-26) and the eastern chemical industry (1991, (1), 24) describe the preparation of ethylenediaminetetraacetic acid (EDTA) from ethylenediamine, chloroacetic acid, sodium carbonate, etc. as raw materials. The process is completed by the working procedures of mixing, condensation, acidification, filtration, washing, drying and the like. The obtained product is white powder, the content of the ethylene diamine tetraacetic acid is more than 98 percent, and the yield is 71 to 80 percent (calculated by the ethylene diamine). Low yield, high cost and environmental pollution.
The invention content is as follows:
the invention aims to provide a method for producing ethylenediamine tetraacetic acid and salt by taking crude hydrocyanic acid synthesis gas as a raw material, which has the advantages of greatly improving the reaction yield of ethylenediamine tetraacetic acid and salt preparation, reducing the production cost, having stable product quality, safer production operation and being beneficial to environmental protection.
The purpose of the invention is realized by the following steps:
the invention relates to a method for preparing ethylene diamine tetraacetic acid and salt from hydrocyanic acid synthesis gas, which comprises the following technological processes:
1) adding a formaldehyde flow into a reaction kettle, and fully mixing and reacting with ethylenediamine in the kettle to synthesize aldehyde-amine mixed solution;
2) introducing hydrocyanic acid synthesis gas, reacting with aldehyde-amine mixed solution, and stirring to generate an intermediate product, namely ethylenediamine diacetonitrile;
3) simultaneously, adding formaldehyde and acid into the kettle, introducing hydrocyanic acid synthetic gas, and stirring to generate ethylene diamine tetraacetic acid acetonitrile;
4) hydrolyzing with alkaline water solution or acid solution to obtain EDTA, adding acid, acidifying to regulate pH to 1-5 to obtain EDTA and salt:
the concentration of the hydrocyanic acid synthetic gas is 5-25% (V/V) under a standard state. The hydrocyanic acid synthesis gas is produced by the Andrussow process, the Degussa process or the Light oil Cracking process.
The reaction temperature of the step 1.1 is controlled to be 0-30 ℃; 1.2, controlling the reaction temperature at 10-60 ℃; 1.3, the reaction temperature in the step is 10-60 ℃; 1.4, the hydrolysis temperature is 90-115 ℃;
the pH value of the reaction step 2 is more than 1.2 and less than 4, and the pH value of the reaction step 3 is more than 1.3 and less than 10.
And (3) stirring at 200-700 rpm in the steps 1.2 and 1.3 to ensure good gas absorption effect, and installing a gas distributor in the kettle to ensure that gas-liquid two phases are fully mixed and absorbed.
The acid mentioned in the above step 1.3 is anorganic acid such as formic acid, acetic acid, etc. and/or an inorganic acid such as sulfuric acid, hydrochloric acid, phosphoric acid, etc. or a mixed acid thereof.
The alkaline aqueous solution in the above step is sodium hydroxide or potassium hydrochloride aqueous solution, and the acid solution is sulfuric acid or hydrochloric acid.
The reaction formula of the invention is as follows:
technical Formaldehyde (HCHO) is generally a 37% strength aqueous solution, ethylenediamine (H)2N-CH2-CH2-NH2) The formaldehyde is mixed and reacted immediately, and a large amount of reaction heat is released, and a reaction kettle is provided with a cooling heat exchange device. To mix the reaction mixture uniformly and avoid local overheating, the reaction should be stirred vigorously during the reaction to ensure efficient reaction. Introducing hydrocyanic acid (HCN) synthesis gas into the reaction kettle to carry out cyanomethylation reaction to generate an intermediate product, namely ethylenediamine diacetonitrile. The reaction is a gas-liquid phase reaction, and the absorption of hydrocyanic acid synthesis gas determines the extent of the reaction. When the temperature of the hydrocyanic acid synthesis gas is higher than 60 ℃, a condenser is additionally arranged before the hydrocyanic acid synthesis gas enters the reaction kettle to reduce the temperature of the gas, and a water separator is additionally arranged to separate a large amount of water carried in the synthesis gas, so that the latent heat contained in water vapor is prevented from entering the kettle; in order to ensure good gas absorption effect, the stirring is carried out at a certain rotating speed (200-700 rpm), and a gas distributor is arranged in the kettle so as to fully mix and absorb gas-liquid phases.
And adding an acid into the obtained reaction liquid (dissolving ethylenediamine diacetonitrile in water) to adjust the pH of the reaction liquid in the kettle to be 2-4. Tong (Chinese character of 'tong')Adding hydrocyanic acid synthesis gas, adding formaldehyde, making further cyanomethylation reaction so as to make ethylenediamine diacetonitrile convert into ethylenediamine tetracetonitrile [ (NC-CH)2)2N-CH2-CH2-N(CH2CN)2]. The formaldehyde flow rate is controlled to keep the temperature of the kettle at 70 ℃. The ethylene diamine tetraacetic acid acetonitrile is gradually separated out, cooled and separated in the later reaction period. The separated acidic mother liquor can be recycled.
The hydrolysis reaction of the obtained ethylenediamine tetraacetic acid nitrile generates ethylenediamine tetraacetic acid { [ (HO)2CCH2)2N-CH2]2Neutralizing with alkaline solution such as sodium hydroxide (NaOH) to obtain ethylenediaminetetraacetic acid and disodium salt (HO)2CCH2)2N-CH2-CH2-N(CH2CO2Na)2]And ethylenediaminetetraacetic acid and tetrasodium salt [ (NaO)2CCH2)2N-CH2-CH2-N(CH2CO2Na)2]The yield of the ethylene diamine tetraacetic acid in the whole reaction is over 95 percent based on the ethylene diamine.
The invention directly adopts the crude hydrocyanic acid synthesis gas as the raw materialto prepare the ethylene diamine tetraacetic acid and the salt, thereby not only greatly improving the reaction yield, but also having stable product quality, reducing the production cost, having safer production operation and being beneficial to environmental protection.
The specific implementation mode is as follows:
example 1:
a500 ml glass three-necked flask with a stirrer is added with 0.2mol of ethylenediamine, 140ml of water and a 100ml dropping funnel, 31ml of formaldehyde is added for feeding, ice water is used for cooling, aldehyde-amine mixed liquid is generated by reaction, hydrocyanic acid gas with the concentration of 20% (V/V) in a standard state is introduced by a glass tube, and a rotameter meters the hydrocyanic acid gas to participate in the reaction. The reaction temperature is 25 ℃, the pH value is 3, and the ethylenediamine diacetonitrile solution is obtained; simultaneously, 40ml of formaldehyde and hydrocyanic acid gas are fed in, the reaction temperature is 60 ℃, the pH value is 5, and 43g of ethylene diamine tetraacetic acid nitrile is obtained.
Ethylenediamine tetraacetic acid acetonitrile 43g with 55% H2Hydrolyzing SO to obtain B58.1g of diamine tetraacetic acid, the content of which is 98.5 percent and the yield is 97.8 percent in terms of ethylenediamine.
The stirring speed during the reaction is 500 rpm.
Example 2:
adding 115kg of ethylenediamine and 1000L of water into a 2000L reaction kettle, adding 280L of formaldehyde (37%) under stirring, stirring after the addition is finished at the stirring speed of 500 rpm for about 30 minutes, and reacting to generate aldehyde-amine mixed solution; introducing hydrocyanic acid synthesisgas with the concentration of 7% (V/V) under the standard state, metering by an orifice plate flowmeter, and introducing about 1200m3Regulating the acidity pH to 3 at 25 deg.c to obtain reaction liquid ethylenediamine diacetonitrile; adding 310L of formaldehyde into the mixture, and introducing 1300m of hydrocyanic acid synthesis gas3The reaction temperature is 60 ℃, the pH value is 7, and 441kg of ethylene diamine tetraacetic acid nitrile is obtained.
441kg of Ethylene Diamine Tetraacetic Acid (EDTA) is added into a 2000L reaction kettle, 800L of water and 830L of 30% sodium hydroxide solution are added, the temperature is raised by stirring, the reaction solution is kept boiling at 102 ℃ for about 1h, activated carbon is added into the reaction solution for decolorization, hydrochloric acid is added to adjust the pH value to be 2, and the reaction solution is dried to obtain 538kg of ethylene diamine tetraacetic acid with the content of 99.0% and the yield of 95% based on the ethylene diamine.
The hydrocyanic acid gas in the above embodiments is prepared by an Andr method, a Digaosha method or a light oil cracking method.
Claims (8)
1. The method for producing the ethylene diamine tetraacetic acid and the salt by taking the hydrocyanic acid synthesis gas as a raw material is characterized by comprising the following technological processes:
1) adding a formaldehyde flow into a reaction kettle, and fully mixing and reacting with ethylenediamine in the kettle to synthesize aldehyde-amine mixed solution;
2) introducing hydrocyanic acid synthesis gas, stirring, and reacting with aldehyde-amine mixed solution to generate an intermediate product, namely ethylenediamine diacetonitrile;
3) simultaneously, adding formaldehyde and acid into the kettle, introducing hydrocyanic acid synthetic gas, and stirring to generate ethylene diamine tetraacetic acid acetonitrile;
4) hydrolyzing with alkaline water solution or acid solution and ethylenediamine tetraacetic acid nitrile to obtain ethylenediamine tetraacetic acid salt, adding acid, acidifying and adjusting pH to 1-5 to obtain ethylenediamine tetraacetic acid and ethylenediamine tetraacetic acid salt:
2. the method for producing ethylenediaminetetraacetic acid and salts from hydrocyanic acid synthesis gas as claimed in claim 1, wherein the hydrocyanic acid synthesis gas has a concentration of 5% to 25% (V/V) under standard conditions.
3. The method for producing ethylenediaminetetraacetic acid and salts from hydrocyanic acid synthesis gas according to claim 1 or 2, wherein the hydrocyanic acid synthesis gas is produced by an Andrussow's method, a Digaosha method or a light oil cracking method.
4. The method for producing ethylenediaminetetraacetic acid and salts from hydrocyanic acid synthesis gas as claimed in claim 1 or 2, wherein the reaction temperature in the 1.1 step is controlled at 0 ℃ to 30 ℃; 1.2, controlling the reaction temperature at 10-60 ℃; 1.3, the reaction temperature in the step is 10-60 ℃; 1.4, the hydrolysis temperature is 90-115 ℃;
5. the method for producing ethylenediaminetetraacetic acid and salts from hydrocyanic acid synthesis gas as claimed in claim 1 or 2, wherein 1.2 reaction step 2<pH<4, 1.3 step 3<pH<10.
6. The method for producing ethylenediaminetetraacetic acid and salts from hydrocyanic acid synthesis gas according to claim 1 or 2, wherein the stirring speed in steps 1.2 and 1.3 is 200-700 rpm.
7. The method for producing ethylenediaminetetraacetic acid and salts from hydrocyanic acid synthesis gas according to claim 1 or 2, wherein said acid in step 1.3 is an organic acid and/or an inorganic acid.
8. The method for producing ethylenediaminetetraacetic acid and salts thereof using hydrocyanic acid synthesis gas as a raw material according to claim 1 or 2, wherein said alkaline aqueous solution in the step is an aqueous solution of sodium hydroxide or potassium hydrochloride, and said acid solution is sulfuric acid or hydrochloric acid.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101723842B (en) * | 2009-11-06 | 2012-11-07 | 重庆紫光鼎福化工有限责任公司 | Method for preparing ethylene diamine tetraacetic acid (EDTA) disodium salt |
| CN102993034A (en) * | 2011-09-19 | 2013-03-27 | 重庆紫光化工股份有限公司 | Preparation method of methyl-glycine diacetate tri-sodium |
| CN103570570A (en) * | 2012-07-23 | 2014-02-12 | 山东旭东化工科技股份有限公司 | Preparation method of tetrasodium ethylenediamine tetraacetate salt complexing agent |
-
2002
- 2002-07-12 CN CN 02133458 patent/CN1388113A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101723842B (en) * | 2009-11-06 | 2012-11-07 | 重庆紫光鼎福化工有限责任公司 | Method for preparing ethylene diamine tetraacetic acid (EDTA) disodium salt |
| CN102993034A (en) * | 2011-09-19 | 2013-03-27 | 重庆紫光化工股份有限公司 | Preparation method of methyl-glycine diacetate tri-sodium |
| CN102993034B (en) * | 2011-09-19 | 2014-11-12 | 重庆紫光化工股份有限公司 | Preparation method of methyl-glycine diacetate tri-sodium |
| CN103570570A (en) * | 2012-07-23 | 2014-02-12 | 山东旭东化工科技股份有限公司 | Preparation method of tetrasodium ethylenediamine tetraacetate salt complexing agent |
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