阅读说明：本技术 一种聚天冬氨酸锌盐的合成方法 (Synthesis method of polyaspartic acid zinc salt ) 是由 程终发 周响 邱玉章 王宁宁 王燕平 于 2019-12-13 设计创作，主要内容包括：发明公开了一种聚天冬氨酸锌盐的生产方法,具体是由氨水控制体系pH值,水解聚琥珀酰亚胺(PSI)得聚天冬氨酸(PASP),同时在铵盐存在下,溶解氢氧化锌/氧化锌为可溶性Zn(NH<Sub>3</Sub>)<Sub>4</Sub>(OH)<Sub>2</Sub>,与聚天冬氨酸反应生成聚天冬氨酸锌。该方法在水解PSI成PASP的同时,与PASP生成聚天冬氨酸锌,两步反应同时进行,缩短了工时,节约了能耗；此法直接与锌盐反应,避免了聚天冬氨酸钙中间体的使用,缩减了工序和工时,节能降耗,且避免了大量钙盐的产生。该方法无副产,无废物产生,绿色环保,利于实现工业化生产。(The invention discloses a production method of polyaspartic acid zinc salt, which comprises the steps of controlling the pH value of a system by ammonia water, hydrolyzing Polysuccinimide (PSI) to obtain Polyaspartic Acid (PASP), and dissolving zinc hydroxide/zinc oxide into soluble Zn (NH) in the presence of ammonium salt 3 ) 4 (OH) 2 And reacting with polyaspartic acid to generate polyaspartic acid zinc. The method hydrolyzes PSI into PASP, and simultaneously generates polyaspartic acid zinc with PASP, and the two-step reaction is carried out simultaneously, thereby shortening the working hours and saving the energy consumption; the method directly reacts with zinc salt, avoids the use of a calcium polyaspartate intermediate, reduces working procedures and working hours, saves energy, reduces consumption and avoids the generation of a large amount of calcium salt. The method has no byproduct and waste, is green and environment-friendly, and is beneficial to realizing industrial production.)

1. The production method of the zinc polyaspartate is characterized by comprising the following specific operation contents:

(1) adding polysuccinimide, a zinc source, ammonium salt and pure water into a reaction kettle, stirring and heating;

(2) dropwise adding ammonia water, maintaining the pH of the system at 8-9 by controlling the dropwise adding speed and the dropwise adding amount of the ammonia water, and continuously reacting until the solid completely disappears to obtain amber transparent liquid;

(3) and adjusting the pH value of the system to 5-6 by using dilute acid, keeping the temperature of the system unchanged, keeping the temperature for 0.5-1 h, and performing spray drying to obtain brown yellow powder zinc salt of polyaspartic acid.

2. The method for producing polyaspartic acid zinc salt according to claim 1, wherein the zinc source is zinc oxide or zinc hydroxide.

3. The method for producing polyaspartic acid zinc salt as claimed in claim 1, wherein the feeding molar ratio of polysuccinimide to zinc in the zinc source is n_PSI：n_ZincAnd (3) the ratio of 1:0.2n to 0.9n, wherein n is the average polymerization degree of PSI.

4. The method as claimed in claim 1, wherein the amount of pure water is 1.5-2.0 times of PSI feed mass; and (2) stirring and heating to 60-100 ℃.

5. The method as claimed in claim 1 or 2, wherein the ammonium salt is a water-soluble zinc salt capable of forming with zinc ions; the dosage of the ammonium salt is 0.5-1.0% of the feeding mass of the zinc source.

6. The production method according to claims 1 and 2, wherein the zinc source can be added in n batches with the interval time of 1h, and n = 1-6.

7. The method for producing polyaspartic acid zinc salt according to claim 1, wherein the concentration of ammonia water is 5-30%.

8. The method for producing polyaspartic acid zinc salt according to claim 1, wherein the dilute acid is an acid capable of forming water-soluble zinc salt with zinc ion, and the mass fraction of the dilute acid is 5-15%.

9. The method as claimed in claim 1, wherein the exhaust gas recovery device is fully opened in steps (1) and (2).

Technical Field

The invention belongs to the technical field of industrial water treatment agent chemical industry, and particularly relates to a production method of polyaspartic acid zinc salt.

Background

Zinc is one of essential trace elements for human body, plays an extremely important role in the growth and development process of human body, is usually praised as 'flowers of life' and 'sources of intelligence', can effectively improve the resistance of human body, and has the same significance for adults and old people to improve the immunity by supplementing zinc to resist epidemic diseases. In China, although the soil is rich in zinc elements, most of the zinc elements in the soil exist in the form of inorganic salts which are difficult to dissolve in water, such as zinc carbonate and the like, and are not easy to be absorbed by crops, so that the condition that the crops are generally lack of zinc is caused, the yield and the quality of the crops are influenced, and the current situation that the national people generally lack of zinc is caused.

In order to solve the problem of zinc deficiency of soil, an efficient and harmless agricultural zinc supplement agent becomes a current research hotspot. The research direction of the agricultural zinc supplement has gradually changed from inorganic zinc to organic zinc, and the research focuses on improving the water solubility of the zinc supplement, degrading organic ligands, causing no pollution and avoiding negative effects on soil, such as soil hardening caused by sulfate radicals.

The polyaspartic acid zinc as a novel organic high-efficiency zinc supplement agent has the following remarkable advantages compared with other zinc supplement agents: the zinc-supplementing agent is easy to degrade in soil and is easy to be absorbed by plants, and is a non-toxic and pollution-free environment-friendly plant zinc-supplementing agent; in addition, the polyaspartic acid radical ions also have the effect of enhancing the absorption of plant nutrient elements and can better supplement other trace elements.

At present, the preparation research of the polyaspartic acid zinc has been advanced. Mainly takes aspartic acid as raw material, polycondenses it into Polysuccinimide (PSI) with different molecular weight, then opens the ring and hydrolyzes it into Polyaspartic Acid (PASP), then complexes zinc salt to be polyaspartic acid zinc. The aspartic acid is a common amino acid, is used as a conventional raw material in the food and chemical industries, is easy to prepare, has rich reserves, and can meet the requirement of industrial production. Chinese patent CN102627766B uses calcium polyaspartate as raw material, and replaces with zinc sulfate under acidic condition, and obtains high-purity zinc polyaspartate through filtering and drying. The raw materials used in the method are downstream products of aspartic acid, the added value is high, the production cost is overhigh, and the product popularization is not facilitated. Zhang Yoming et al disclose a method for rapidly synthesizing high-purity spiral chain-like zinc L-aspartate by using L-aspartate and zinc oxide under microwave radiation (China science, chemistry, 2004, 34). The method has high synthesis speed and high purity, but cannot realize large-scale production due to equipment limitation.

Disclosure of Invention

Aiming at the existing defects, the invention provides a production method of polyaspartic acid zinc salt, which mainly comprises the following steps:

the production process of zinc polyaspartate includes the following steps:

(1) adding polysuccinimide, a zinc source, ammonium salt and pure water into a reaction kettle, stirring and heating;

(2) dropwise adding ammonia water, maintaining the pH of the system at 8-9 by controlling the dropwise adding speed and the dropwise adding amount of the ammonia water, and continuously reacting until the solid completely disappears to obtain amber transparent liquid;

(3) and adjusting the pH value of the system to 5-6 by using dilute acid, keeping the temperature of the system unchanged, keeping the temperature for 0.5-1 h, and performing spray drying to obtain brown yellow powder zinc salt of polyaspartic acid.

Wherein the zinc source is zinc oxide or zinc hydroxide.

Wherein the feeding molar ratio of the zinc in the polysuccinimide and the zinc source is n_PSI：n_ZincAnd (4) the ratio of 1:0.2n-0.9n, wherein n is the average polymerization degree of PSI.

Wherein the consumption of the pure water is 1.5-2.0 times of the PSI feeding mass; and (2) stirring and heating to 60-100 ℃.

Wherein, the ammonium salt can form water-soluble zinc salt with zinc ions; the dosage of the ammonium salt is 0.5-1.0% of the feeding mass of the zinc source.

The zinc source can be added in n batches, the batch adding interval time is 1h, and n = 1-6.

Wherein the concentration of the ammonia water is 5-30%.

The diluted acid is an acid capable of forming a water-soluble zinc salt with zinc ions, and the mass fraction of the diluted acid is 5-15%.

Wherein, in the steps (1) and (2), the tail gas recovery device is started in the whole process.

The invention has the beneficial effects that: the method comprises the steps of controlling the pH value of a system by ammonia water, and hydrolyzing Polysuccinimide (PSI) to obtain polyaspartic acid(PASP) dissolving zinc hydroxide/zinc oxide in the presence of an ammonium salt to form soluble Zn (NH)₃)₄(OH)₂And reacting with polyaspartic acid to generate polyaspartic acid zinc.

The method hydrolyzes PSI into PASP, and simultaneously generates polyaspartic acid zinc with PASP, and the two-step reaction is carried out simultaneously, thereby shortening the working hours and saving the energy consumption; the method directly reacts with zinc salt, avoids the use of a calcium polyaspartate intermediate, reduces working procedures and working hours, saves energy, reduces consumption and avoids the generation of a large amount of calcium salt. The method has no byproduct and waste, is green and environment-friendly, and is beneficial to realizing industrialization.

Detailed Description