阅读说明：本技术 一种环保甜菜碱的制备方法 (Preparation method of environment-friendly betaine ) 是由 刘长飞 李志伟 王云鹤 于 2019-02-03 设计创作，主要内容包括：本发明提供了一种环保高品质甜菜碱的制备方法,生产甜菜碱的同时联产农用氯化铵。首先氯乙酸与氨或者是碳酸氢铵反应合成氯乙酸铵固体中间体,氯乙酸铵固体在乙醇或甲醇溶剂中与三甲胺进行季铵化反应,合成甜菜碱(三甲基甘氨酸)和氯化铵。氯乙酸铵与三甲胺在有机溶剂的季铵化反应,可以加入催化剂4-二甲氨基吡啶,也可以加入氢氧化钾调节溶液的PH值。(The invention provides a preparation method of environment-friendly high-quality betaine, which is used for producing betaine and coproducing agricultural ammonium chloride. Firstly, chloroacetic acid reacts with ammonia or ammonium bicarbonate to synthesize an ammonium chloroacetate solid intermediate, and the ammonium chloroacetate solid reacts with trimethylamine in an ethanol or methanol solvent to carry out quaternization reaction, so that betaine (trimethylglycine) and ammonium chloride are synthesized. The quaternization reaction of ammonium chloroacetate and trimethylamine in an organic solvent can be carried out by adding a catalyst of 4-dimethylamino pyridine or adding potassium hydroxide to adjust the pH value of the solution.)

1. A method for preparing environment-friendly betaine, ammonium chloroacetate and trimethylamine react in ethanol or methanol solvent to prepare betaine and coproduce agricultural ammonium chloride, a catalyst 4-Dimethylaminopyridine (DMAP) can be used, and potassium hydroxide can be added to adjust the pH value of the solution, and the method is characterized by comprising the following steps:

1) introducing ammonia or adding ammonium bicarbonate into chloroacetic acid in an aqueous solution to synthesize ammonium chloroacetate, cooling, filtering to obtain ammonium chloroacetate solid, and recycling the filtrate to prepare ammonium chloroacetate;

2) adding solvent ethanol or methanol into a betaine synthesis reactor, adding solid ammonium chloroacetate or ethanol or methanol solution of the ammonium chloroacetate, controlling the temperature to be between 40 and 70 ℃, adding gaseous trimethylamine or liquid trimethylamine, or adding trimethylamine ethanol solution or trimethylamine methanol solution, and carrying out quaternization;

3) adding solvent ethanol or methanol into a betaine synthesis reactor, optionally adding catalyst 4-Dimethylaminopyridine (DMAP), or adding potassium hydroxide to adjust the pH value of the solution, and performing quaternization reaction of ammonium chloroacetate and trimethylamine;

4) after the quaternization reaction of ammonium chloroacetate and trimethylamine is finished, cooling to 10-50 ℃, centrifugally separating solid ammonium chloride, washing with ethanol or methanol, and drying to obtain a byproduct, namely agricultural ammonium chloride;

5) centrifugally separating out an ethanol or methanol solvent, distilling and recovering the ethanol or methanol, wherein the volume of the distilled ethanol or methanol is 30-60% of the volume of the original solvent, cooling to 10-30 ℃, centrifugally separating and washing to obtain a crude solid betaine product;

6) centrifuging the organic solvent obtained from crude betaine, adding ethanol (or methanol), adding solid ammonium chloroacetate (or mixing with ammonium chloroacetate to prepare a solvent), adding gaseous trimethylamine or liquid trimethylamine according to a proportion, or adding trimethylamine ethanol solution or trimethylamine methanol solution, and circularly performing quaternization;

7) recrystallizing the crude betaine product by adopting a recrystallization process, wherein the solvent can be an aqueous solution or a mixed solvent consisting of water and ethanol or methanol to obtain an industrial-grade betaine product;

8) when the content of ammonium chloride in the solvent for recrystallizing the crude betaine is enriched to 20-30%, evaporating and concentrating, recovering the solvent, cooling, crystallizing and centrifuging to obtain a mixed crystal solid of the betaine and the ammonium chloride, drying the mixed crystal solid, and separating and recovering the betaine and the ammonium chloride in a mode of heating and dissolving ethanol or methanol;

9) the method comprises the steps of synthesizing a circulating reaction solvent of betaine and ammonium chloride, recycling ethanol or methanol in the solvent after a certain number of times of circulating use, distilling the remaining substances, performing catalytic oxidation, adding urea, performing reduced pressure evaporation, cooling crystallization and filtering to obtain a byproduct agricultural ammonium chloride fertilizer raw material.

2. The method of claim 1, wherein: the mol ratio of the ammonium chloroacetate to the trimethylamine in the step 2) is 1: 1-1.1, and the weight ratio of the ammonium chloroacetate to the ethanol or the methanol is 1: 1-10.

3. The method of claim 1, wherein: the mol ratio of ammonium chloroacetate to DMAP catalyst in the step 3) is 1: 0.0001-0.05, and the mol ratio of ammonium chloroacetate to potassium chloride is 1: 0.01-0.1.

4. The method of claim 1, wherein: and 4) after the quaternization reaction of the ammonium chloroacetate and the trimethylamine is finished, cooling to 10-50 ℃, centrifugally separating out solid ammonium chloride, washing with ethanol or methanol, and drying to obtain a byproduct, namely agricultural ammonium chloride.

5. The method of claim 1, wherein: the volume of the distilled ethanol or methanol in the step 5) is 30-60% of the volume of the original solvent, the temperature is reduced to 10-30 ℃, and the solid betaine crude product is obtained through centrifugal separation and washing.

6. The method of claim 1, wherein: the crude betaine in the step 7) adopts a recrystallization process, and the solvent can be an aqueous solution or a mixed solvent consisting of water and ethanol or methanol.

7. The method of claim 1, wherein: and 8) separating and recovering the betaine and the ammonium chloride from the mixed crystal solid of the betaine and the ammonium chloride in a heating and dissolving mode of ethanol or methanol.

8. The method of claim 1, wherein: and 9) distilling the cyclic reaction solvent to recover ethanol or methanol, performing catalytic oxidation, adding urea, performing reduced pressure evaporation, cooling crystallization, and filtering to obtain a byproduct, namely an agricultural ammonium chloride fertilizer raw material.

Technical Field

The invention relates to a preparation method of environment-friendly betaine, which is used for producing betaine and co-producing ammonium chloride, and belongs to the technical field of chemical production.

Background

Betaine is also called betaine and trimethylglycine, and has good physical and chemical properties, good stability and oxidation resistance, high temperature resistance and acid and alkali resistance; the chemical structure of the compound is similar to that of amino acid and choline, has various biological functions, and is widely applied to the fields of feed additives, pharmaceutical industry, agriculture and forestry production, food additives, daily chemicals and the like. Has moisture keeping effect in cosmetic; the medicine has the effect of protecting liver, and the food has American FDA approval of betaine as a safe food additive and a dietary nutrition enhancer; the betaine can improve the utilization rate of energy in food, improve the effective absorption and utilization rate of amino acid, and protect liver; the feed additive is more widely applied to livestock, poultry and aquatic animals, can improve the utilization level of daily ration energy, stabilizes the quality of vitamins in the feed, has a protective effect on fat-soluble vitamins, can adjust osmotic pressure, is beneficial to maintaining the water and ion balance of cells, has obvious effects of maintaining the integrity of intestinal tracts and the health of the intestinal tracts when the animals generate stress, reduces the death of the aquatic animals in the processes of fishing and transporting, and reduces the cost of the feed. There are two main methods for production: separating from beet molasses, and synthesizing by chemical method.

Usually, chloroacetic acid, sodium hydroxide or sodium carbonate and trimethylamine are used as raw materials for neutralization reaction, then quaternization reaction is carried out, ion resin or membrane separation is adopted, and then drying is carried out to obtain betaine or betaine hydrochloride is continuously prepared. In a word, the existing processes of betaine and betaine hydrochloride are not easy to control, byproducts are easy to generate, the investment is large, the product yield is low, a large amount of waste water is generated, and great environmental pressure is generated. In particular, sodium chloride as a byproduct is only treated as a solid waste because it contains organic substances.

Disclosure of Invention

The invention provides a preparation method of environment-friendly high-quality betaine, which is used for producing betaine and coproducing agricultural ammonium chloride by-products. Firstly, chloroacetic acid reacts with ammonia (liquid ammonia or ammonia water) or ammonium bicarbonate to synthesize an ammonium chloroacetate solid intermediate, and the ammonium chloroacetate solid reacts with trimethylamine in an ethanol or methanol solvent to carry out quaternization reaction to synthesize betaine (trimethylglycine) and ammonium chloride. The quaternization reaction of ammonium chloroacetate and trimethylamine in an organic solvent can be carried out by adding a catalyst of 4-Dimethylaminopyridine (DMAP) or adding potassium hydroxide to adjust the pH value of the solution.

The invention is realized by the following steps and methods:

step (1), preparing an intermediate ammonium chloroacetate solid:

chloroacetic acid (solid chloroacetic acid or liquid chloroacetic acid) is introduced into aqueous solution for ammonia reaction (20-55 ℃), ammonium chloroacetate is synthesized, the temperature is reduced to 10-30 ℃ and ammonium chloroacetate solid is obtained by filtration. Or solid ammonium bicarbonate can be used to react with chloroacetic acid aqueous solution to synthesize ammonium chloroacetate, the reaction temperature is controlled at (10-30 ℃), the temperature is reduced to room temperature of 10-30 ℃, and ammonium chloroacetate solid is obtained by filtering. And (3) adding chloroacetic acid and ammonia or adding ammonium bicarbonate into the filtrate to circularly react to prepare ammonium chloroacetate, wherein the filtrate is a saturated aqueous solution of ammonium chloroacetate.

After the saturated aqueous solution of ammonium chloroacetate is circulated for a certain number of times, the color becomes dark due to the enrichment of impurities such as dichloroacetic acid, acetic acid and the like contained in the ammonium chloroacetate, and the following treatment modes can be adopted:

firstly, activated carbon is adopted for adsorption and decoloration, and then the activated carbon is continuously recycled. When the ammonium dichloroacetate content in the aqueous solution is enriched to about 20% -30%, adding a small amount of urotropine (or 4-Dimethylaminopyridine (DMAP)) into the ammonium chloroacetate aqueous solution, slowly introducing ammonia for reaction at the temperature of 50-70 ℃, and stopping the reaction when the pH value reaches 6.8-7.5. The purpose of this treatment is to convert ammonium chloroacetate in aqueous solution to glycine and ammonium chloride. The waste water is firstly subjected to catalytic oxidation, then urea is added, pressure reduction evaporation, cooling crystallization and filtration are carried out, and a byproduct agricultural ammonium chloride fertilizer raw material is obtained (or a reaction solution is subjected to catalytic oxidation, added with urea and then directly dried, and the byproduct agricultural ammonium chloride fertilizer raw material is obtained).

Step (2), preparing ammonium chloride in ethanol or methanol solvent by taking solid ammonium chloroacetate as a raw material:

adding solvent ethanol or methanol into a reactor (including a kettle reactor, a tubular reactor and a microreactor) for synthesizing betaine, and adding solid ammonium chloroacetate proportionally, or adding ammonium chloroacetate ethanol or methanol solution in batches or dropwise. Gaseous trimethylamine or liquid trimethylamine is added according to the proportion, and trimethylamine ethanol solution or trimethylamine methanol solution can be added for quaternization. The reaction temperature is 40-70 ℃. The mol ratio of ammonium chloroacetate to trimethylamine is 1: 1-1.1, and the weight ratio of ammonium chloroacetate to ethanol or methanol is 1: 1-10.

In order to accelerate the quaternization reaction speed of ammonium chloroacetate and trimethylamine in an organic solvent, a catalyst 4-Dimethylaminopyridine (DMAP) can be added, and potassium hydroxide can also be added to adjust the pH value of the solution. The mol ratio of ammonium chloroacetate to DMAP catalyst is 1: 0.0001-0.05. The mol ratio of ammonium chloroacetate to potassium chloride is 1: 0.01-0.1.

After the quaternization reaction of ammonium chloroacetate and trimethylamine is finished, solid ammonium chloride is centrifugally separated out at the temperature of 10-50 ℃, and a byproduct, namely agricultural ammonium chloride is obtained after washing and drying by ethanol or methanol.

Step (3), preparing a crude product of betaine (trimethylglycine):

and (3) centrifugally separating out the solvent (ethanol or methanol solvent) in the step (2), distilling and recovering ethanol or methanol, wherein the volume of the distilled ethanol or methanol is 30-60% of the volume of the original solvent, cooling to 10-30 ℃, centrifugally separating, and washing to obtain a crude solid betaine product.

And (4) preparing byproducts of betaine and ammonium chloride by a circular reaction:

in a betaine synthesis reactor, the organic solvent centrifugally separated in the step (3) is taken, ethanol (or methanol) recovered by distillation or methanol or ethanol for washing ammonium chloride and betaine is added, solid ammonium chloroacetate (or the solid ammonium chloroacetate is mixed with the ammonium chloroacetate to prepare a solvent) is added, gaseous trimethylamine or liquid trimethylamine is added according to a proportion, and a trimethylamine ethanol solution or a trimethylamine methanol solution is added, so that the quaternization reaction is carried out in a circulating manner.

And (5) recrystallizing the crude betaine product to refine the crude betaine product into an industrial-grade betaine product:

and (3) obtaining the industrial grade betaine from the betaine crude product obtained in the steps by adopting a recrystallization process. The solvent for recrystallization may be an aqueous solution or a mixed solvent of water and ethanol or methanol.

And (3) recycling the recrystallized solvent, and when the content of ammonium chloride in the solvent is enriched to 20-30%, evaporating and concentrating, recovering the solvent, cooling, crystallizing and centrifuging to obtain the mixed crystal solid of the betaine and the ammonium chloride. And (3) after the mixed crystal solid is dried, separating and recovering the betaine and the ammonium chloride in a mode of heating and dissolving ethanol or methanol.

And (6) circulating reaction solvent treatment:

the cyclic reaction solvent for synthesizing the betaine and the ammonium chloride is subjected to impurity enrichment and color deepening after being recycled for a certain number of times, and needs to be treated regularly. The following method is adopted for treatment:

firstly, ethanol or methanol in the solvent is recovered by distillation. Distilling the remaining substances, adding the distilled substances into the aqueous solution of ammonium chloride and glycine to be treated in the step (1), firstly performing catalytic oxidation, then adding urea, performing reduced pressure evaporation, cooling crystallization and filtering to obtain a byproduct agricultural ammonium chloride fertilizer raw material (or directly drying a reaction solution after performing catalytic oxidation and adding urea to obtain the byproduct agricultural ammonium chloride fertilizer raw material).

The catalytic oxidation process of the wastewater in the steps comprises the following steps: fenton oxidation (Fenton), photocatalytic oxidation, ozone catalytic oxidation, electrochemical oxidation, ultrasonic oxidation, supercritical water oxidation, wet catalytic oxidation and the like.

During the above waste water treatment, urea is required to be added, the nitrogen content of the ammonium chloride product is increased, and the product can reach the standard specified by the national standard of ammonium chloride (GB/T2946-2008 ammonium chloride).

The diameter of the micro-porous membrane of the micro-reactor is 1 micron-10 microns, the channel size of the flow-through phase is 1 mm-20 mm, the reaction time is 0.1-30 minutes, and the reaction temperature is 65-85 ℃. In the present invention, a membrane-dispersed microstructure reactor is preferably selected. The number of microchannel reactors is not particularly limited. When more than 2 microchannel reactors are used, each microchannel reactor is configured in series, and reaction raw materials sequentially enter each microchannel reactor. The structure of the microchannel reactor includes, but is not limited to, a rectangle, a trapezoid, a heart, a double trapezoid, and an irregular shape. In the reaction, the microchannel reactor may be used as different modules as needed, such as a mixing preheating module, a reaction module, a cooling module, and the like. These modules are only functionally distinct and the geometry may be identical.

The specific embodiment is as follows:

the following examples are provided to further illustrate the essence of the present invention, but are not intended to limit the present invention.