Method for preparing stannous neodecanoate through one-step synthesis

Abstract

The invention discloses a method for preparing stannous neodecanoate through one-step synthesis, and belongs to the technical field of chemical product preparation methods. The method comprises the following steps: adding neodecanoic acid, stannous oxide and water into a reaction container according to a ratio, uniformly stirring, sealing the reaction container, and heating under reduced pressure until the temperature is greater than or equal to 105 DEG C to promote the reaction of neodecanoic acid and stannous oxide to obtain synthetic slurry; the synthetic slurry is divided into three layers, the upper layer is unreacted neodecanoic acid with the specific gravity of 0.92, the middle layer is water with the specific gravity of 1, and the lower layer is stannous neodecanoate slurry with the specific gravity of 1.25; and carrying out liquid-solid separation on the stannous neodecanoate slurry at the lower layer to obtain a liquid which is a stannous neodecanoate intermediate product, and carrying out reduced pressure distillation dehydration to obtain a stannous neodecanoate product. Other impurities are not added in the reaction process of the method, and the produced stannous neodecanoate product is high in purity and good in quality. The production process is short, unreacted residues are unreacted stannous oxide which can be recycled, the raw material loss is small, no waste gas is generated in the reaction process, and the method is energy-saving and environment-friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical product preparation methods, and in particular to a preparation method of stannous neodecanoate. Background Art

[0002] Stannous neodecanoate, chemically known as stannous 2,2-dimethyloctoate, is a pale yellow to amber transparent liquid or paste, a tin chemical product. Because stannous neodecanoate readily hydrolyzes in both acidic and alkaline aqueous solutions, its stable pH range is relatively narrow, and it is easily oxidized and decomposed by oxygen in the air and other oxidants, making its preparation difficult. The reported production method for stannous neodecanoate involves first reacting metallic tin with hydrochloric acid to produce a stannous chloride solution, then mixing the stannous chloride solution with a sodium carbonate solution to produce a stannous bicarbonate intermediate, which is then esterified with neodecanoic acid to produce stannous neodecanoate. This method is relatively easy to scale up, as the raw materials, metallic tin and hydrochloric acid, are relatively low-cost, the process is simplified, and complex washing and distillation processes are unnecessary, with a direct yield exceeding 98%. However, this process still has some problems. The main ones are the need to first prepare tin salts such as stannous chloride, the need to fully neutralize the neodecanoic acid during the reaction, the high alkali consumption, the poor stability of the synthesis process, and the strict control of the feed rate, system pH value, and the composition of the various raw materials. Improper control of conditions or changes in the raw material composition can easily lead to substandard products. Furthermore, the presence of Cl- in the reaction can affect the purity of the final product. Furthermore, the production process requires the use of large amounts of deionized water to wash the sodium chloride from the neodecanoic acid, generating large amounts of difficult-to-treat high-sodium salt wastewater, which places great pressure on wastewater treatment.

[0003] Patent application publication number CN110396042A discloses a method for preparing stannous octadecanoate. While this method utilizes neodecanoic acid and stannous oxide to synthesize stannous octadecanoate, it suffers from serious process flaws. First, the reaction control and raw material dosages suffer from significant technical deficiencies: no water is added during the reaction, and the molar ratio of stannous oxide to neodecanoic acid is 1.0:2.0-5.0. The reaction, which terminates with the complete reaction of the stannous oxide, requires a large excess of neodecanoic acid (excess neodecanoic acid). The reaction is initiated at a temperature of approximately 90°C. The exothermic reaction between stannous oxide and neodecanoic acid results in a vigorous heat release upon initiation, making temperature control difficult. The maximum reaction temperature can reach ≥150°C. This intense heat release also causes a short-term surge in the reactor pressure (because the vapor pressure of neodecanoic acid increases with temperature, and there is no water dilution to mitigate the reaction intensity), requiring equipment with a higher pressure resistance. Secondly, the product is difficult to separate: after the reaction is completed, only cooling and filtration are performed to obtain stannous neodecanoate product. However, since a large amount of unreacted neodecanoic acid (boiling point 270~280℃) remains in the product, and the boiling point of stannous neodecanoate (256℃) is lower than that of neodecanoic acid, only the reaction water can be evaporated during distillation, and the residual acid in the product cannot be effectively separated, resulting in low main content and poor purity of the product. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for producing stannous neodecanoate which has a short production process, low production cost, energy conservation and environmental protection, and can ensure the purity of the final product and good product quality.

[0005] The purpose of the present invention is achieved through the following technical solutions: The invention discloses a one-step synthetic preparation method of stannous neodecanoate. The method comprises the following steps: adding neodecanoic acid, stannous oxide and water into a reaction container in proportion and stirring them evenly; sealing the reaction container, heating under reduced pressure to ≥105°C, promoting the reaction between the neodecanoic acid and the stannous oxide, and obtaining a synthetic slurry; then settling the mixture to stand, and the synthetic slurry is separated into three layers, the upper layer being unreacted neodecanoic acid with a specific gravity less than that of water, the middle layer being water with a specific gravity of 1, and the lower layer being stannous neodecanoate slurry with a specific gravity greater than that of water; removing the stannous neodecanoate slurry from the lower layer for liquid-solid separation, and obtaining a stannous neodecanoate intermediate liquid, which is dehydrated by reduced pressure distillation to obtain a stannous neodecanoate product.

[0006] Furthermore, the liquid-to-solid ratio of the liquid portion composed of neodecanoic acid and water to the solid stannous oxide is 3-8:1 by mass, and the mass ratio of neodecanoic acid to water is 1:0.4-1.5 by mass. The main purpose of adding a large amount of water during the reaction is to absorb the reaction heat, accelerate the dissociation of neodecanoic acid, and physically separate the stannous neodecanoate, water, and neodecanoic acid.

[0007] Furthermore, the amount of stannous oxide added is 1.2 times or more of the theoretical amount.

[0008] Furthermore, neodecanoic acid, water and stannous oxide react in a negative pressure environment in a reaction container, and the reaction pressure is ≥-0.02 MPa.

[0009] Furthermore, the slag obtained by liquid-solid separation is residual stannous oxide, and the slag is returned for use in synthesizing stannous neodecanoate.

[0010] Compared with the prior art, the present invention has at least the following advantages: (1) The present invention directly uses stannous oxide and neodecanoic acid as raw materials to synthesize stannous neodecanoate in one step. In particular, water is added to dilute the concentration of neodecanoic acid during the reaction, and an excess of stannous oxide is used to feed the material, so that the reaction of the neodecanoic acid is more complete and the residual acid is small. The addition of water also effectively alleviates the intensity of the reaction, avoids excessive temperature, makes the reaction process easier to control, and greatly reduces safety risks.

[0011] (2) The reaction process of the present invention does not add other impurities, effectively avoiding the participation of inorganic anions such as Cl- in the reaction, and can ensure the purity and quality stability of the final product. The product purity is ≥99%.

[0012] (3) In the process of the present invention, the large amount of water added will absorb the heat generated by the reaction, thereby accelerating the reaction process, and can dilute the concentration of neodecanoic acid, increase the free neodecanoate ions, and improve the reaction rate, which helps to improve the utilization rate of neodecanoic acid and make the neodecanoic acid reaction more complete.

[0013] (4) The method of the present invention realizes that after the reaction is completed, the product is clearly divided into three layers. The upper layer is unreacted light neodecanoic acid, which can be directly returned to production for use. The middle layer is water, which effectively separates the unreacted neodecanoic acid from the reaction product stannous neodecanoate slurry located in the lower layer, so that the stannous neodecanoate slurry with a high effective content can be directly separated. The stannous neodecanoate slurry is subjected to solid-liquid separation to remove the unreacted stannous oxide and return it to the synthesis cycle. The liquid part is vacuum distilled (controlled at 105°C) to evaporate the water (boiling point is about 95°C), thus obtaining a high-purity stannous neodecanoate product with a purity greater than 99%. This effectively solves the problems of the prior art that the reaction process is difficult to control, there are safety hazards, and the purity of the stannous neodecanoate product is not high.

[0014] (5) The present invention directly uses stannous oxide as raw material. The slag produced during the reaction is unreacted tin slag, which can be directly returned to synthesize stannous neodecanoate. The raw materials can be fully utilized with low loss. The upper and middle layers of the synthetic slurry can be returned to the system for re-reaction. The distilled water produced by vacuum distillation can be collected and returned for synthesizing stannous neodecanoate. The production process does not generate waste gas, which is energy-saving and environmentally friendly.

[0015] (6) The method of the present invention has a short production process and a relatively simple preparation method. It does not require complicated preparation processes and production equipment investment. The production cost is low and the process is easy to control, making it easy to achieve large-scale controllable production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] A one-step synthetic method for preparing stannous neodecanoate, such as Figure 1 As shown, the steps are as follows: (1) Add neodecanoic acid and water to a sealable reaction vessel, start stirring, and slowly add stannous oxide in proportion. Seal the reaction vessel, reduce the negative pressure to 0.02 MPa, and raise the temperature to 105°C to promote the reaction between neodecanoic acid and stannous oxide. The reaction time is controlled to be ≥2 hours to obtain a synthetic slurry. The liquid-to-solid mass ratio of the liquid portion composed of neodecanoic acid and water to the solid stannous oxide is 3-8:1; the mass ratio of neodecanoic acid to water is 1:0.4-1.5, and the amount of stannous oxide is more than 1.2 times the theoretical amount. Diluting neodecanoic acid in an aqueous solution can increase its dissociation degree and the reaction speed, thereby making it easier to form stannous neodecanoate. In addition, the water layer can regulate the reaction temperature and absorb the heat released during the reaction.

[0019] The reaction formula for the synthesis reaction of stannous oxide and neodecanoic acid is as follows: SnO+2C 10 H 20 O2=C 20 H 38 O4 Sn+ H2O ; (2) The synthetic slurry is allowed to settle and stand. After standing, the synthetic slurry is divided into three layers, the upper layer is unreacted light neodecanoic acid (specific gravity 0.92), the middle layer is water with a specific gravity of 1, and the lower layer is stannous neodecanoate slurry with a specific gravity of 1.25; the stannous neodecanoate slurry of the lower layer is taken for liquid-solid separation, the liquid portion (synthetic liquid) after separation is the intermediate product of stannous neodecanoate, and the solid portion, i.e., the slag (synthetic slag), is the unreacted stannous oxide, which can be recycled and further used in the synthesis reaction to prepare stannous neodecanoate; (3) The stannous neodecanoate intermediate in the lower layer is subjected to vacuum distillation to obtain the desired stannous neodecanoate product. The aqueous solution obtained by vacuum distillation can meet the discharge standards and can also be recycled; (4) Pack the stannous neodecanoate product and store it in the warehouse. Example 1

[0020] A one-step synthetic method for preparing stannous neodecanoate involves adding 600g of neodecanoic acid and 250g of water to a 2L glass flat-bottom flask. Stirring is initiated, followed by the addition of 282g of stannous oxide. The flask is sealed and evacuated to a negative pressure of 0.02 MPa. The temperature is then raised to 105°C and the reaction time is set for 2 hours. After the reaction is complete, the slurry is cooled to room temperature, allowed to settle, and allowed to settle. The resulting slurry separates into three layers: an upper layer containing unreacted neodecanoic acid, a middle layer containing water, and a lower layer containing stannous neodecanoate slurry. The lower layer of stannous neodecanoate slurry is then removed for liquid-solid separation. The separated residue, representing 44.2g of unreacted stannous oxide, can be reused for further preparation of stannous neodecanoate. The separated liquid, a stannous neodecanoate intermediate, is then distilled under reduced pressure to remove water, yielding 789.6g of stannous neodecanoate product. Titration indicates a purity of 99.24%. The stannous neodecanoate is packaged and ready for sale. Example 2

[0021] A one-step synthetic method for preparing stannous neodecanoate involves adding 600g of neodecanoic acid and 600g of water to a 2L glass flat-bottom flask. 350g of stannous oxide is then added while stirring. The flask is sealed and evacuated to a negative pressure of 0.02 MPa. The temperature is then raised to 105°C, and the reaction time is set. After the reaction is complete, the slurry is cooled to room temperature, allowed to settle, and allowed to stand. The resulting slurry separates into three layers: an upper layer containing unreacted neodecanoic acid, a middle layer containing water, and a lower layer containing stannous neodecanoate slurry. The lower layer of stannous neodecanoate slurry is removed for liquid-solid separation, yielding 104.2g of unreacted stannous oxide as a residue, which can be recycled. The separated liquid, a stannous neodecanoate intermediate, is then distilled under reduced pressure to remove water, yielding 797.2g of stannous neodecanoate product. Testing indicates a purity of 99.18%. The stannous neodecanoate is packaged and ready for sale. Example 3

[0022] A one-step synthetic method for preparing stannous neodecanoate involves adding 400g of neodecanoic acid and 600g of water to a 2L glass flat-bottom flask. During stirring, 190g of stannous oxide is then added. The flask is sealed and evacuated to a negative pressure of 0.02 MPa. The temperature is then raised to 105°C, and the reaction time is set. After the reaction is complete, the slurry is cooled to room temperature, allowed to settle, and allowed to stand. The resulting slurry separates into three layers: an upper layer containing unreacted neodecanoic acid, a middle layer containing water, and a lower layer containing stannous neodecanoate slurry. The lower layer of stannous neodecanoate slurry is removed for liquid-solid separation, yielding 35.8g of unreacted stannous oxide, which can be recycled. The separated liquid, a stannous neodecanoate intermediate, is then distilled under reduced pressure to remove water, yielding 528.3g of stannous neodecanoate product. Testing indicates a purity of 99.16%. The stannous neodecanoate is packaged and ready for sale. Example 4

[0023] A one-step synthetic method for preparing stannous neodecanoate involves adding 400g of neodecanoic acid and 500g of water to a 2L glass flat-bottom flask. 90g of stannous oxide is then added while stirring. The flask is sealed and evacuated to a negative pressure of 0.02 MPa. The temperature is then raised to 105°C, and the reaction time is set for 3 hours. After the reaction is complete, the slurry is cooled to room temperature, allowed to settle, and allowed to stand. The resulting slurry separates into three layers: an upper layer containing unreacted neodecanoic acid, a middle layer containing water, and a lower layer containing stannous neodecanoate slurry. The lower layer of stannous neodecanoate slurry is removed for liquid-solid separation, yielding 17.8g of unreacted stannous oxide, a residue that can be recycled. The separated liquid, a stannous neodecanoate intermediate, is then distilled under reduced pressure to remove water, yielding 411.2g of stannous neodecanoate product. Testing indicates a purity of 99.23%. Stannous neodecanoate is packaged and ready for sale.

[0024] The raw materials neodecanoic acid and stannous oxide used in the method of the present invention are both commercially available. When the method of the present invention is expanded to actual production, a vacuum tank with an internal stirring device and a heating function commonly used in the prior art can be used as a reaction vessel.

Claims

1. A one-step synthetic method for preparing stannous neodecanoate, characterized in that: Neodecanoic acid, stannous oxide, and water are added to a reaction vessel in proportion and stirred evenly. After the reaction vessel is sealed, it is heated under reduced pressure to ≥105°C to promote the reaction between the neodecanoic acid and the stannous oxide to obtain a synthetic slurry. The reaction vessel is then allowed to settle and stand, and the synthetic slurry is divided into three layers, the upper layer being unreacted neodecanoic acid with a specific gravity less than that of water, the middle layer being water with a specific gravity of 1, and the lower layer being stannous neodecanoate slurry with a specific gravity greater than that of water. The stannous neodecanoate slurry in the lower layer is taken for liquid-solid separation, and the separated liquid is a stannous neodecanoate intermediate, which is dehydrated by reduced pressure distillation to obtain a stannous neodecanoate product.

2. A method for preparing stannous neodecanoate by one-step synthesis according to claim 1, characterized in that: The liquid-to-solid mass ratio of the liquid part composed of the neodecanoic acid and water to the solid stannous oxide is 3-8:1; the mass ratio of the neodecanoic acid to water is 1:0.4-1.

5.

3. A method for preparing stannous neodecanoate by one-step synthesis according to claim 1 or 2, characterized in that, The amount of stannous oxide added is 1.2 times or more of the theoretical amount.

4. A method for preparing stannous neodecanoate by one-step synthesis according to claim 1 or 2, characterized in that, Neodecanoic acid, water and stannous oxide react in a negative pressure environment in a reaction container, and the reaction pressure is ≥-0.02 MPa.

5. A method for preparing stannous neodecanoate by one-step synthesis according to claim 1 or 2, characterized in that, The slag obtained after liquid-solid separation is residual stannous oxide, which is returned to be used for synthesizing stannous neodecanoate.

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