Method and device for synthesizing stannous octoate

Abstract

The invention provides a method and a device for synthesizing stannous octoate. The method provided by the invention comprises the step of reacting tin and isocaprylic acid in the presence of an antioxidant and oxygen-containing gas to obtain a reaction solution containing stannous octoate. According to the method and the device disclosed by the invention, stannous octoate with high purity and high yield can be obtained from tin and isocaprylic acid at normal pressure in one step, and a byproduct is only water, so that the method and the device are green and efficient.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for synthesizing stannous octoate. Background Art

[0002] Stannous octoate is an oily liquid with the chemical formula C 16 H 30 O 4 Sn. It is a polyurethane synthesis catalyst, mainly used in the production of soft block foams. It can also be used in the fields of (polyurethane) coatings and elastomers, and as a polymerization initiator in the production of polyesters such as rubber and polylactic acid.

[0003] The commonly reported synthesis processes of stannous octoate basically use expensive tin oxide or stannous chloride as starting materials. For example, in the common saponification method for synthesizing stannous octoate, sodium carbonate or sodium hydroxide is first used to react with isooctanoic acid to prepare sodium isooctanoate, and then stannous chloride solution is added to prepare stannous octoate. Or isooctanoic acid and stannous chloride solution are mixed and then sodium hydroxide or sodium carbonate solution is added for neutralization to form stannous octoate. This method has low requirements for equipment and is easy to achieve large-scale production. However, this method also has the following disadvantages: 1. A large amount of alkali solution is required in the neutralization process, and the control of pH and the ratio of raw material components are extremely strict. If the conditions are not well controlled, the product may be unqualified; 2. A large amount of alkaline sodium salts are used in the production process, and a large amount of water is required for desalting in the post-treatment, resulting in the generation of a large amount of high-salt sewage, which is not environmentally friendly and causes great pressure on sewage treatment. In addition, in the method of synthesizing stannous octoate by the tin oxide method, stannous oxide and isooctanoic acid are mixed in proportion, heated above 150 °C under vacuum and reduced pressure for dehydration, and then the product is obtained by filtration. Although this method is environmentally friendly, it uses expensive tin oxide as a raw material. The above two methods will both result in high costs.

[0004] The reaction of synthesizing stannous octoate by the saponification method is as follows:

[0005]

[0006] The reaction of synthesizing stannous octoate by stannous oxide is as follows:

[0007]

[0008] Patent CN110330423B discloses a method for directly synthesizing stannous octoate using the tin pressurization method. Specifically, isooctanoic acid, refined tin and water are put into a closed container and heated above 150 °C under the condition of a pressure greater than 1 MPa to react to prepare stannous octoate. Although this method has a short process flow, the reaction pressure is high, the requirements for equipment are high, and at the same time, the by-product is H 2 , which also has a certain degree of danger. Summary of the Invention

[0009] To solve the problems of high cost, harsh reaction conditions, long process flow, and high salt content in wastewater in the existing stannous octoate synthesis process, the present invention provides a stannous octoate production process with a short production process flow, high production efficiency, mild reaction conditions, low production cost, and high safety. Under the protection of an antioxidant, stannous octoate is directly prepared by reacting refined tin with isooctanoic acid in the presence of an oxygen-containing gas, and the by-product is water, which is environmentally friendly. In addition, the present invention also provides a device for synthesizing stannous octoate.

[0010] The technical solution of the present invention is as follows:

[0011] In a first aspect, the present invention provides a method for synthesizing stannous octoate, comprising the following steps:

[0012] React tin with isooctanoic acid in the presence of an antioxidant and an oxygen-containing gas to obtain a reaction solution containing stannous octoate.

[0013] According to some embodiments of the present invention, when the mass content of divalent tin ions in the reaction solution is above 16.0%, for example, 16.0 - 28.0% (16.0%, 17.0%, 18.0%, 19.0%, 20.0%, 21.0%, 22.0%, 23.0%, 24.0%, 25.0%, 26.0%, 27.0%, 28.0% or any value therebetween), the reaction is stopped. In some embodiments, when the mass content of divalent tin ions in the reaction solution is 20.0% - 28.0%, the reaction is stopped. In some embodiments, when the mass content of divalent tin ions in the reaction solution is 24.0% - 28.0%, the reaction is stopped.

[0014] According to some embodiments of the present invention, the mass ratio of tin to isooctanoic acid is (0.25 - 4):1, for example, 0.25:1, 0.3:1, 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1 or any value therebetween. In some embodiments, the mass ratio of tin to isooctanoic acid is (0.4 - 3):1. In some embodiments, the mass ratio of tin to isooctanoic acid is (1 - 3):1. In the present invention, increasing the mass ratio of tin to isooctanoic acid is beneficial to improving the reaction yield.

[0015] The method of the present invention oxidizes the raw material tin into divalent tin by adding an antioxidant, preventing the formation of excessive tetravalent tin. According to some embodiments of the present invention, the dosage of the antioxidant is 0.05% to 2.0% of the mass of isooctanoic acid, for example, 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2% or any value between them, preferably 0.1% to 1.5%, more preferably 0.4% to 1.2%. It has been found through research in the present invention that the selection of the type of antioxidant has an important impact on the yield and purity of stannous octoate. The antioxidant of the present invention is preferably one or more of aromatic esters containing tert-butyl, phosphites containing phenyl or long-chain alkyl, and phenols containing tert-butyl. According to some embodiments of the present invention, the antioxidant includes one or several of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, p-tert-butylcatechol, tris(octadecyl) phosphite. In some embodiments, the antioxidant includes phenols containing tert-butyl, aryl phosphites with or without tert-butyl, or a combination thereof. In some embodiments, the antioxidant includes one or more of p-tert-butylcatechol, a combination of p-tert-butylcatechol and tris(octadecyl) phosphite, a combination of p-tert-butylcatechol and triphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite. In some embodiments, the antioxidant includes p-tert-butylcatechol.

[0016] The oxygen-containing gas described in the present invention includes but is not limited to: oxygen, air, etc.

[0017] According to some embodiments of the present invention, the temperature of the reaction is 120 to 180 °C, for example, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C or any value between them, preferably 130 - 165 °C, more preferably 150 - 165 °C. According to some embodiments of the present invention, the reaction time is 6 - 24 hours, for example, 6 hours, 8 hours, 10 hours, 12 hours, 16 hours, 18 hours, 20 hours, 24 hours or any value between them.

[0018] According to some embodiments of the present invention, the method includes the following steps:

[0019] Mix tin, isooctanoic acid and the antioxidant to obtain a mixture;

[0020] An oxygen-containing gas is introduced into the mixture, and the reaction is heated to obtain a reaction solution containing stannous octoate; wherein the reaction is stopped when the mass content of divalent tin ions in the reaction solution is 16.0%-28.0%.

[0021] In some embodiments, the rate of introducing the oxygen-containing gas is 50-200 mL / min, for example, 50 mL / min, 80 mL / min, 100 mL / min, 150 mL / min, 200 mL / min or any value therebetween.

[0022] In some embodiments, the method further includes: before introducing the oxygen-containing gas, a first inert gas is also introduced into the mixture. In some embodiments, heating is also performed after introducing the first inert gas, preferably heating to 110-120 °C.

[0023] In some embodiments, the method further includes: after introducing the oxygen-containing gas, a second inert gas is introduced into the reaction solution containing stannous octoate.

[0024] In the present invention, the first inert gas and the second inert gas may be the same or different. In the present invention, the inert gas includes but is not limited to: nitrogen, argon, helium or a mixture of two or more of them.

[0025] In some embodiments, the time for introducing the second inert gas is 0.5-4.0 hours, preferably 2.0-3.0 hours.

[0026] In some embodiments, the rate of introducing the second inert gas is 50-200 mL / min.

[0027] According to some embodiments of the present invention, the method further includes: subjecting the reaction solution to vacuum distillation to obtain isooctanoic acid and a crude product of stannous octoate, wherein the crude product of stannous octoate is washed and dried to obtain a pure product of stannous octoate. In the present invention, the isooctanoic acid obtained by vacuum distillation can be directly used as a raw material for the production of the next batch of stannous octoate.

[0028] In a second aspect, the present invention provides an apparatus for synthesizing stannous octoate, the apparatus includes a reaction tower, a feeding port is provided at the top of the reaction tower, the feeding port is used to allow tin pellets, isooctanoic acid and an antioxidant to enter the reaction tower, an oxygen-containing gas inlet and a filter plate are provided at the bottom of the reaction tower, the filter plate is used to discharge the reaction solution after the reaction of tin pellets and isooctanoic acid, so as to monitor the mass content of divalent tin ions in the reaction solution.

[0029] The apparatus of the present invention can be used to implement the method for synthesizing stannous octoate described in the first aspect of the present invention.

[0030] According to some embodiments of the present invention, the ratio of the diameter to the height of the reaction tower is 1:(4-10), such as 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or any value therebetween.

[0031] According to some embodiments of the present invention, a plurality of tin storage trays parallel to the bottom of the reaction tower and having a horizontal length less than the diameter of the reaction tower are provided on the inner wall of the reaction tower, for enabling tin pellets to fully contact and react with isooctanoic acid and an oxygen-containing gas on the tin storage trays.

[0032] According to some embodiments of the present invention, the tin storage trays are arranged in a staggered manner left and right on the inner wall of the reaction tower.

[0033] According to some embodiments of the present invention, the maximum length of the tin storage tray in the horizontal direction is 1 / 2 to 2 / 3 of the diameter of the reaction tower.

[0034] According to some embodiments of the present invention, the height difference between two adjacent tin storage trays and the diameter of the reaction tower have a ratio of 1:(0.5-1.0).

[0035] According to some embodiments of the present invention, the tin storage tray is polygonal or bow-shaped, preferably semi-circular.

[0036] According to some embodiments of the present invention, a plurality of small holes are distributed on the tin storage tray, and the diameter of the small holes is smaller than the diameter of the tin pellets; preferably, the diameter of the small holes is 0.5-1.5 mm, more preferably 0.5-1.0 mm.

[0037] According to some embodiments of the present invention, an inert gas inlet is further provided at the bottom of the reaction tower.

[0038] According to some embodiments of the present invention, a purification device is further connected to the bottom of the reaction tower, for purifying the reaction liquid discharged from the filter plate to obtain a stannous octoate product.

[0039] According to some embodiments of the present invention, the filter plate only allows liquids and gases to pass through.

[0040] According to some embodiments of the present invention, the device further includes:

[0041] a condenser for condensing the gas phase containing isooctanoic acid obtained at the top of the reaction tower; and

[0042] an oil-water separator for separating the liquid phase condensed from the condenser to obtain isooctanoic acid and water.

[0043] In some embodiments, the oil-water separator has an oil phase outlet, and the oil phase outlet communicates with the top of the reaction tower, so that the isooctanoic acid separated by the oil-water separator returns to the reaction tower for reuse.

[0044] In a third aspect, the present invention provides an application of the device described in the second aspect in the preparation of stannous octoate.

[0045] Compared with the prior art, the present invention has the following beneficial technical effects:

[0046] 1. In the method of the present invention, by selecting a suitable antioxidant, stannous octoate is directly prepared by reacting refined tin with isooctanoic acid in the presence of an oxygen-containing gas. By monitoring the mass content of stannous ions in the reaction solution within a suitable range, the reaction yield and product purity are improved. The by-product is water, which is environmentally friendly. The method of the present invention can carry out the reaction under normal pressure, with mild conditions, short process flow, high production efficiency, low production cost, and high safety.

[0047] 2. The device of the present invention can enable solid tin and liquid isooctanoic acid to fully contact and react in the presence of an oxygen-containing gas, realize the reaction of a gas-solid-liquid three-phase system, and directly separate the remaining tin after the reaction from the reaction solution and leave it in the reaction tower, which is convenient for the reuse of tin, and can monitor the mass content of stannous ions in the reaction solution at any time, which is beneficial to improving the reaction yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Shows the device for synthesizing stannous octoate used in the embodiments of the present invention.

[0049] Figure 2 Shows the front view of the reaction tower in the device for synthesizing stannous octoate used in the embodiments of the present invention.

[0050] Figure 3 Shows the process flow chart for synthesizing stannous octoate in the embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. The specific embodiments described herein are only used to explain the present invention and do not constitute any limitation to the present invention.

[0052] The reagents used in the following experiments of the present invention are all conventional commercially available products or reagents prepared by conventional methods, unless otherwise specified. The methods used in the experiments are all conventional experimental methods, unless otherwise specified. The instruments used in the experiments can be obtained through commercial channels, unless otherwise specified.

[0053] The reaction for preparing stannous octoate in the present invention is as follows:

[0054]

[0055] As shown Figure 1 in the figure, as a specific embodiment, the device for synthesizing stannous octoate according to the present invention includes a reaction tower, a condenser and an oil-water separator; a feeding port is provided at the top of the reaction tower, and tin pellets, isooctanoic acid and an antioxidant enter the reaction tower from the feeding port; a plurality of tin storage trays parallel to the bottom of the reaction tower and with a horizontal length less than the diameter of the reaction tower are arranged on the inner wall of the reaction tower. The tin pellets are stacked on the tin storage trays from top to bottom in sequence through the feeding port, contact with the isooctanoic acid in the reaction tower and react. The tin storage trays have dense holes; air enters the reaction tower from the air inlet at the bottom of the reaction tower to participate in the reaction; a filter plate is arranged at the bottom of the reaction tower, and only liquid and gas can pass through the filter plate. The filter plate is used to discharge the reaction liquid obtained after the reaction of tin pellets and isooctanoic acid, so as to monitor the mass content of divalent tin ions in the reaction liquid. See the front view of the reaction tower in Figure 2 .

[0056] After the reaction is completed, the corresponding mass of tin pellets can be added according to the total tin content in the reaction liquid for the next batch of production.

[0057] Further, when the mass content of divalent tin ions in the reaction liquid reaches 16.0 - 28.0%, the reaction is stopped.

[0058] Further, the ratio of the diameter to the height of the reaction tower is 1:(4 - 10); preferably 1:(6 - 7).

[0059] Further, the shape of the tin storage tray is: a circular tray with a diameter equal to the inner diameter of the reaction tower is cut into a semi-circular shape of 1 / 2 - 1 / 3, preferably 1 / 2 semi-circular shape.

[0060] Further, the tin storage trays are arranged in a staggered manner left and right. Further, the arc edges of the tin storage trays and the filter plate are tightly welded to the reaction tower respectively.

[0061] Further, a plurality of small holes with a diameter smaller than the diameter of the tin pellets are distributed on the tin storage trays. For example, the diameter of the small holes is 0.5 - 1.5 mm, preferably 0.5 - 1.0 mm.

[0062] Further, the condenser is used to condense the gas phase containing isooctanoic acid obtained at the top of the reaction tower; the oil-water separator is used to separate the liquid phase condensed from the condenser to obtain isooctanoic acid and water.

[0063] Even further, the oil-water separator has an oil phase outlet, and the oil phase outlet is communicated with the top of the reaction tower so that the isooctanoic acid separated by the oil-water separator returns to the reaction tower for reuse.

[0064] As a specific embodiment, the method for synthesizing stannous octoate of the present invention is as follows:

[0065] Using the device as Figure 1 shown, add tin granules from the feed inlet, and the tin granules are stacked on the tin storage tray from top to bottom in sequence; then add isooctanoic acid to ensure that all the tin granules are submerged, and then add an antioxidant. While bubbling with nitrogen, turn on the hot oil heating (for example, 120 °C), close the nitrogen valve, turn on the air pump and continuously introduce air, control the temperature at 120 °C to 180 °C and react for 6 to 24 hours, close the air valve and the pump, introduce nitrogen bubbling for heat preservation reaction for a period of time, take samples for detection until the mass content of stannous ions in the reaction solution is 16.0 to 28.0%, cool down and discharge the reaction solution from the bottom of the reaction tower through the filter plate. The discharged reaction solution is subjected to vacuum distillation to recover isooctanoic acid until the total tin and stannous contents in the reaction solution reach the standard, followed by cooling water washing, vacuum dehydration and cooling to obtain the stannous octoate product; the unreacted tin granules in the reaction tower are left in the tower, and then isooctanoic acid and antioxidant are replenished to enter the next batch of stannous octoate production.

[0066] All the following examples of the present invention use the production device as Figure 1 and Figure 2 shown for the synthesis of high-quality stannous octoate, and the synthesis process flow chart is as Figure 3 shown.

[0067] Unless otherwise specified, in the following examples and comparative examples of the present invention, "total tin content" represents the mass content of total tin in the product; "stannous content" represents the mass content of stannous (stannous ions) in the product.

[0068] Example 1

[0069] Put 200.0 g of tin granules, 800.0 g of isooctanoic acid, and 2.0 g of p-tert-butylcatechol into the reactor. While bubbling with nitrogen, turn on the hot oil heating. When the temperature rises to 135 °C in about 1.0 h, close the nitrogen valve, turn on the air pump and continuously introduce air at 120 mL / min, control the temperature at 160 °C and react for 24 h, close the air valve and the air pump, introduce nitrogen at 120 mL / min for bubbling and heat preservation at 160 °C for 2.0 h, and take samples to measure that the mass content of stannous ions is 16.50%. Cool down to 130 °C and discharge the reaction solution through the filter plate. The excessive tin in the reaction tower can be used for the next batch of stannous octoate production. The reaction solution is subjected to vacuum distillation at 130 °C to recover the excessive isooctanoic acid for the next batch of production. The remaining stannous octoate is washed with water, dehydrated at 100 °C and then cooled to obtain 572.31 g, with a yield of 83.85%; the total tin content is 29.35%, and the stannous content is 28.19%.

[0070] Example 2

[0071] In the reactor of Example 1, tin pellets were added to the reactor until the weight of the tin pellets in the reactor was 310.0 g, isooctanoic acid was 750.0 g, and p-tert-butylcatechol was 4.5 g. Then, they were put into the reactor. While nitrogen was bubbling, the hot oil heating was turned on. It took about 1.0 h to heat up to 135°C, and then the nitrogen valve was closed. The air pump was turned on and air was continuously introduced at 120 mL / min. The temperature was controlled at 160°C and the reaction was carried out for 20.0 h. Then, the air valve and the air pump were closed, and nitrogen was introduced at 120 mL / min for bubbling and heat preservation at 160°C for 2.0 h. The mass content of divalent tin ions measured by sampling was 21.50%. The temperature was lowered to 130°C, and the reaction solution was discharged through the filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130°C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C, and then cooled to obtain 963.14 g, with a yield of 91.04%; the total tin content was 28.91%, and the stannous content was 28.03%.

[0072] Example 3

[0073] In the reactor of Example 2, tin pellets were added to the reactor until the weight of the tin pellets in the reactor was 1000.0 g. Then, 500.0 g of isooctanoic acid and 4.0 g of p-tert-butylcatechol were added in sequence. While nitrogen was bubbling, the hot oil heating was turned on. It took about 1.0 h to heat up to 135°C, and then the nitrogen valve was closed. The air pump was turned on and air was continuously introduced at 160 mL / min. The temperature was controlled at 152°C and the reaction was carried out for 11.0 h. Then, the air valve and the air pump were closed, and nitrogen was introduced at 160 mL / min for bubbling and heat preservation at 152°C for 2.0 h. The mass content of divalent tin ions measured by sampling was 26.11%. The temperature was lowered to 130°C, and the reaction solution was discharged through the filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130°C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C, and then cooled to obtain 673.20 g, with a yield of 95.86%; the total tin content was 29.13%, and the stannous content was 28.15%.

[0074] Example 4

[0075] In the reactor of Example 3, tin pellets were added to the reactor to a weight of 1000.0 g of tin pellets. Then, 500.0 g of isooctanoic acid and 5.88 g of p-tert-butylcatechol were added successively. While bubbling with nitrogen, hot oil heating was turned on. It was heated to 135 °C for about 1.0 h, then the nitrogen valve was closed, and an air pump was turned on to continuously introduce air at 160 mL / min. The temperature was controlled at 152 °C and reacted for 10.0 h. Then the air valve and the air pump were closed, and nitrogen was introduced at 160 mL / min for bubbling and insulation at 152 °C for 2.0 h. The mass content of divalent tin ions was measured to be 25.71% by sampling. The temperature was lowered to 130 °C, and the reaction solution was discharged through a filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130 °C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100 °C, and then cooled to obtain 651.41 g, with a yield of 92.75%; the total tin content was 28.72%, and the stannous content was 28.11%.

[0076] Example 5

[0077] In the reactor of Example 4, tin pellets were added to the reactor to a weight of 1000.00 g of tin pellets. Then, 500 g of isooctanoic acid and 4.0 g of p-tert-butylcatechol were added successively. While bubbling with nitrogen, hot oil heating was turned on. It was heated to 130 °C for about 1.0 h, then the nitrogen valve was closed, and an air pump was turned on to continuously introduce air at 160 mL / min. The temperature was controlled at 130 °C and reacted for 12.0 h. Then the air valve and the air pump were closed, and nitrogen was introduced at 160 mL / min for bubbling and insulation at 130 °C for 3.0 h. The mass content of divalent tin ions was measured to be 22.83% by sampling. The reaction solution was discharged through a filter plate while it was hot. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130 °C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100 °C, and then cooled to obtain 587.45 g, with a yield of 83.65%; the total tin content was 28.99%, and the stannous content was 28.04%.

[0078] Example 6

[0079] Add tin particles to the reactor of Example 5 until the weight of the tin particles in the reactor is 1000.0g, then add 500.0g of isooctanoic acid, 1.0g of tert-butyl catechol, and 3.0g of trioctadecyl phosphite in sequence, turn on the hot oil heating while bubbling with nitrogen, heat to 135°C for about 1.0h, close the nitrogen valve, turn on the air pump to continuously pass air at 160mL / min, control the temperature at 152°C for 10.0h, close the air valve and the air pump, pass nitrogen at 160mL / min, bubble and keep warm at 152°C for 2.0h, sample and measure the mass content of divalent tin ions to be 23.89%. Cool to 130°C and release the reaction solution through the filter plate, and the excess tin in the reaction tower can be used for the next batch of stannous octoate production. The reaction solution was distilled at 130°C under reduced pressure to recover excess isooctanoic acid which could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C and cooled to obtain 601.35 g, with a yield of 85.63%; the total tin content was 28.69% and the stannous content was 27.82%.

[0080] Example 7

[0081] Add tin particles to the reactor of Example 6 until the weight of the tin particles in the reactor is 1000.0g, then add 250.0g of isooctanoic acid and 1.0g of p-tert-butylcatechol in sequence, turn on the hot oil heating while bubbling with nitrogen, heat to 135°C for about 1.0h, close the nitrogen valve, turn on the air pump to continuously pass air at 160mL / min, control the temperature at 160°C to react for 8.0h, close the air valve and the air pump, pass nitrogen at 160mL / min, bubble and keep warm at 152°C to react for 2.0h, sample and measure the mass content of divalent tin ions to be 26.00%. Cool to 130°C and release the reaction solution through the filter plate, and the excess tin in the reaction tower can be used for the next batch of stannous octoate production. The reaction solution was distilled at 130°C under reduced pressure to recover excess isooctanoic acid which could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C and cooled to obtain 326.41 g, with a yield of 92.96%; the total tin content was 28.52% and the stannous content was 27.98%.

[0082] Example 8

[0083] In the reactor of Example 7, tin granules were added to the reactor to a weight of 1000.0 g of tin granules. Then, 500.0 g of isooctanoic acid, 1.0 g of triphenyl phosphite, and 1.0 g of p-tert-butylcatechol were added in sequence. While bubbling with nitrogen, the hot oil heating was turned on. It took about 1.0 h to heat up to 135°C, then the nitrogen valve was closed, and an air pump was turned on to continuously introduce air at 160 mL / min. The temperature was controlled at 160°C and the reaction was carried out for 15.0 h. Then, the air valve and the air pump were closed, and nitrogen was introduced at 160 mL / min for bubbling and heat preservation at 160°C for 2.0 h. The mass content of divalent tin ions measured by sampling was 22.18%. The temperature was lowered to 130°C, and the reaction solution was discharged through a filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130°C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C, and then cooled to obtain 567.79 g, with a yield of 80.85%; the total tin content was 28.93%, and the stannous content was 27.78%.

[0084] Example 9

[0085] In the reactor of Example 8, tin granules were added to the reactor to a weight of 1000.0 g of tin granules. Then, 500.0 g of isooctanoic acid and 4.0 g of p-tert-butylcatechol were added in sequence. While bubbling with nitrogen, the hot oil heating was turned on. It took about 1.0 h to heat up to 135°C, then the nitrogen valve was closed, and an air pump was turned on to continuously introduce air at 50 mL / min. The temperature was controlled at 160°C and the reaction was carried out for 21.0 h. Then, the air valve and the air pump were closed, and nitrogen was introduced at 50 mL / min for bubbling and heat preservation at 160°C for 4.0 h. The mass content of divalent tin ions measured by sampling was 21.86%. The temperature was lowered to 130°C, and the reaction solution was discharged through a filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130°C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C, and then cooled to obtain 598.77 g, with a yield of 85.26%; the total tin content was 29.33%, and the stannous content was 28.09%.

[0086] Example 10

[0087] In the reactor of Example 9, add tin granules to the reactor until the weight of the tin granules in the reactor is 1000.0 g. Then, successively add 500.0 g of recycled isooctanoic acid and 4.0 g of p-tert-butylcatechol. While bubbling nitrogen, turn on the hot oil heating. Raise the temperature to 135 °C for about 1.0 h, then close the nitrogen valve. Turn on the air pump and continuously introduce air at 160 mL / min. Control the temperature at 160 °C and react for 10.0 h. Then, close the air valve and the air pump, introduce nitrogen at 160 mL / min for bubbling, and keep the temperature at 160 °C for reaction for 2.0 h. Take a sample and measure that the mass content of stannous ions is 25.97%. Cool down to 130 °C and discharge the reaction solution through the filter plate. The excess tin in the reaction tower can be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution is recovered by vacuum distillation at 130 °C and can be used for the next batch of production. The remaining stannous octoate is washed with water, dehydrated at 100 °C, and then cooled to obtain 659.83 g, with a yield of 93.95%; the total tin content is 28.64%, and the stannous content is 28.25%.

[0088] Example 11

[0089] In the reactor of Example 10, add tin granules to the reactor until the weight of the tin granules in the reactor is 1000.0 g. Then, successively add 500.0 g of isooctanoic acid and 4.0 g of tris(2,4-di-tert-butylphenyl) phosphite. While bubbling nitrogen, turn on the hot oil heating. Raise the temperature to 135 °C for about 1.0 h, then close the nitrogen valve. Turn on the air pump and continuously introduce air at 160 mL / min. Control the temperature at 160 °C and react for 12.0 h. Then, close the air valve and the air pump, introduce nitrogen at 160 mL / min for bubbling, and keep the temperature at 160 °C for reaction for 2.0 h. Take a sample and measure that the stannous content is 24.59%. Cool down to 130 °C and discharge the reaction solution through the filter plate. The excess tin in the reaction tower can be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution is recovered by vacuum distillation at 130 °C and can be used for the next batch of production. The remaining stannous octoate is washed with water, dehydrated at 100 °C, and then cooled to obtain 623.79 g, with a yield of 88.82%; the total tin is 29.38%, and the stannous content is 28.57%.

[0090] Example 12

[0091] In the reactor of Example 11, tin pellets were added to the reactor to a weight of 1000.0 g of tin pellets. Then, 500.0 g of isooctanoic acid and 4.0 g of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate were added in sequence. While bubbling with nitrogen, the hot oil heating was turned on. The temperature was raised to 135°C in about 1.0 h, then the nitrogen valve was closed, and an air pump was turned on to continuously introduce air at 160 mL / min. The temperature was controlled at 152°C and the reaction was carried out for 11.0 h. Then, the air valve and the air pump were closed, and nitrogen was introduced at 160 mL / min for bubbling to keep the temperature at 152°C and the reaction was carried out for 2.0 h. The mass content of divalent tin ions measured by sampling was 23.78%. The temperature was lowered to 130°C and the reaction solution was discharged through a filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130°C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C, and then cooled to obtain 583.22 g, with a yield of 83.05%; the total tin content was 30.01%, and the stannous content was 28.16%.

[0092] Example 13

[0093] In the reactor of Example 12, tin pellets were added to the reactor to a weight of 1000.0 g of tin pellets. Then, 500.0 g of isooctanoic acid and 4.0 g of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate were added in sequence. While bubbling with nitrogen, the hot oil heating was turned on. The temperature was raised to 135°C in about 1.0 h, then the nitrogen valve was closed, and an air pump was turned on to continuously introduce air at 160 mL / min. The temperature was controlled at 152°C and the reaction was carried out for 11.0 h. Then, the air valve and the air pump were closed, and nitrogen was introduced at 160 mL / min for bubbling to keep the temperature at 152°C and the reaction was carried out for 2.0 h. The mass content of divalent tin ions measured by sampling was 22.53%. The temperature was lowered to 130°C and the reaction solution was discharged through a filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130°C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C, and then cooled to obtain 550.37 g, with a yield of 78.37%; the total tin content was 29.33%, and the stannous content was 27.63%.

[0094] Example 14

[0095] In the reactor of Example 12, 1000.0 g of tin granules were added to the reactor, and then 500.0 g of isooctanoic acid and 4.0 g of tris(octadecyl) phosphite were added in sequence. While bubbling with nitrogen, the hot oil heating was turned on. It was heated to 135°C for about 1.0 h, then the nitrogen valve was closed, the air pump was turned on, and air was continuously introduced at 160 mL / min. The temperature was controlled at 152°C and the reaction was carried out for 11.0 h. Then the air valve and the air pump were closed, and nitrogen was introduced at 160 mL / min for bubbling to keep the temperature at 152°C and react for 2.0 h. The mass content of divalent tin ions measured by sampling was 14.95%. The temperature was lowered to 130°C, and the reaction solution was discharged through the filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130°C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C, and then cooled to obtain 361.24 g, with a yield of 51.44%; the total tin content was 28.53%, and the stannous content was 28.33%.

[0096] Comparative Example 1

[0097] The difference from Example 3 is that the reaction time and the mass content of divalent tin ions at the time of sampling are different. Specifically as follows:

[0098] 1000.0 g of tin granules were added to the reactor, and then 500.0 g of isooctanoic acid and 4.0 g of p-tert-butylcatechol were added in sequence. While bubbling with nitrogen, the hot oil heating was turned on. It was heated to 135°C for about 1.0 h, then the nitrogen valve was closed, the air pump was turned on, and air was continuously introduced at 160 mL / min. The temperature was controlled at 152°C and the reaction was carried out for 5.0 h. Then the air valve and the air pump were closed, and nitrogen was introduced at 160 mL / min for bubbling to keep the temperature at 152°C and react for 2.0 h. The mass content of divalent tin ions measured by sampling was 12.51%. The temperature was lowered to 130°C, and the reaction solution was discharged through the filter plate. The excess tin in the reaction tower could be used for the production of stannous octoate in the next batch. The excess isooctanoic acid in the reaction solution was recovered by vacuum distillation at 130°C and could be used for the next batch of production. The remaining stannous octoate was washed with water, dehydrated at 100°C, and then cooled to obtain 321.45 g, with a yield of 45.77%; the total tin content was 28.92%, and the stannous content was 27.87%.

[0099] Comparative Example 2

[0100] The difference from Example 3 is that no antioxidant is added. Specifically as follows:

[0101] Add 1000.0 g of tin granules to the reactor, then add 500.0 g of isooctanoic acid. While bubbling nitrogen, turn on the hot oil heating. When the temperature rises to 135 °C in about 1.0 h, close the nitrogen valve, turn on the air pump and continuously introduce air at 160 mL / min. Control the temperature at 152 °C and react for 11.0 h. Then close the air valve and the air pump, introduce nitrogen at 160 mL / min for bubbling and keep the temperature at 152 °C for reaction for 2.0 h. Take a sample and measure that the mass content of stannous ions is 8.18%, and there are also a large amount of khaki solids (later identified as tin oxide). Cool down to 130 °C and discharge the reaction solution through the filter plate. The reaction solution is subjected to vacuum distillation at 130 °C to recover the excessive isooctanoic acid, which can be used for the next batch of production. The remaining stannous octoate is washed with water, dehydrated at 100 °C and then cooled to obtain 350.42 g, with a yield of 49.90%; the total tin content is 22.23%, and the stannous content is 11.44%.

[0102] The technical solution of the present invention is not limited to the limitations of the above specific embodiments. Any technical deformation made according to the technical solution of the present invention falls within the protection scope of the present invention.

Claims

1. A method for synthesizing stannous octoate, comprising the steps of: Tin and isooctanoic acid are reacted in the presence of an antioxidant and an oxygen-containing gas to obtain a reaction solution containing stannous octoate.

2. The method according to claim 1, characterized in that When the mass content of divalent tin ions in the reaction solution is 16.0% or more, preferably 16.0-28%, more preferably 20.0%-28.0%, further preferably 24.0%-28.0%, the reaction is stopped; and / or The mass ratio of tin to isooctanoic acid is (0.25-4):1, preferably (0.4-3):1, more preferably (1-3):1; and / or The amount of the antioxidant used is 0.05% to 2.0% of the mass of isooctanoic acid, preferably 0.1% to 1.5%, and more preferably 0.4% to 1.2%.

3. The method according to claim 1 or 2, characterized in that: The antioxidant includes one or more of an aromatic ester antioxidant containing tert-butyl, a phosphite antioxidant containing phenyl or long-chain alkyl, and a phenolic antioxidant containing tert-butyl; and / or the oxygen-containing gas includes oxygen or air; Preferably, the antioxidant includes one or more of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, tri(2,4-di-tert-butyl)phenyl phosphite, p-tert-butylcatechol, and tri(octadecyl) phosphite; Preferably, the antioxidant comprises a phenolic antioxidant containing a tert-butyl group, an aromatic phosphite antioxidant containing or not containing a tert-butyl group, or a combination thereof; More preferably, the antioxidant includes one or more of p-tert-butylcatechol, a combination of p-tert-butylcatechol and trioctadecyl phosphite, a combination of p-tert-butylcatechol and triphenyl phosphite, and tri(2,4-di-tert-butyl)phenyl phosphite.

4. The method according to any one of claims 1 to 3, characterized in that: The reaction temperature is 120-180° C., preferably 130-165° C., more preferably 150-165° C.; and / or the reaction time is 6-24 hours.

5. The method according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: Mixing tin, isooctanoic acid and the antioxidant to obtain a mixture; Passing oxygen-containing gas into the mixture, heating for reaction, and obtaining a reaction solution containing stannous octoate; wherein the reaction is stopped when the mass content of divalent tin ions in the reaction solution is 16.0%-28.0%; Preferably, the rate of introducing the oxygen-containing gas is 50 to 200 mL / min; Preferably, the method further comprises: before introducing the oxygen-containing gas, introducing a first inert gas into the mixture; and / or, after introducing the oxygen-containing gas, introducing a second inert gas into the reaction solution containing stannous octoate; Preferably, the first inert gas and the second inert gas are the same or different, and are each independently selected from nitrogen, argon, helium or a mixture of two or more thereof; Preferably, the time for passing the second inert gas is 0.5-4.0 hours, preferably 2.0-3.0 hours; Preferably, the rate of introducing the second inert gas is 50-200 mL / min.

6. The method according to any one of claims 1 to 5, characterized in that: Also includes: The reaction solution is subjected to reduced pressure distillation to obtain isooctanoic acid and crude stannous octoate, wherein the crude stannous octoate is washed and dried to obtain pure stannous octoate; and the isooctanoic acid is reused as a raw material.

7. A device for synthesizing stannous octoate, comprising a reaction tower, wherein a feeding port is provided at the top of the reaction tower, wherein the feeding port is used to allow tin particles, isooctanoic acid and an antioxidant to enter the reaction tower, and an oxygen-containing gas inlet and a filter plate are provided at the bottom of the reaction tower, wherein the filter plate is used to release a reaction liquid after the reaction of the tin particles and isooctanoic acid, thereby monitoring the mass content of divalent tin ions in the reaction liquid; Preferably, the device is used to implement the method according to any one of claims 1-6.

8. The device according to claim 7, characterized in that The inner wall of the reaction tower is provided with a plurality of tin storage plates which are parallel to the bottom of the reaction tower and whose horizontal length is smaller than the diameter of the reaction tower, so as to allow the tin particles to fully contact with isooctanoic acid and oxygen-containing gas on the tin storage plates and react; and / or The bottom of the reaction tower is also provided with an inert gas inlet; and / or The bottom of the reaction tower is also connected to a purification device for purifying the reaction liquid released from the filter plate to obtain a stannous octoate product; Preferably, the tin storage tower plates are arranged alternately on the inner wall of the reaction tower; Preferably, the maximum length of the tin storage tower plate in the horizontal direction is 1 / 2 to 2 / 3 of the diameter of the reaction tower; Preferably, the ratio of the height difference between two adjacent tin storage tower plates to the diameter of the reaction tower is 1:(0.5-1.0); Preferably, the tin storage tower plate is polygonal or arcuate, preferably semicircular; Preferably, a plurality of small holes are distributed on the tin storage tower plate, and the diameter of the small holes is smaller than the diameter of the tin particles; preferably, the diameter of the small holes is 0.5-1.5 mm, more preferably 0.5-1.0 mm.

9. The device according to any one of claims 7 or 8, characterized in that The device also includes: a condenser, the condenser being used to condense the gas phase containing isooctanoic acid obtained at the top of the reaction tower; and An oil-water separator, which is used to separate the liquid phase obtained by condensation from the condenser to obtain isooctanoic acid and water; Preferably, the oil-water separator has an oil phase outlet, and the oil phase outlet is connected to the top of the reaction tower, so that the isooctanoic acid separated by the oil-water separator is returned to the reaction tower for reuse.

10. Use of the device according to any one of claims 7 to 9 in the preparation of stannous octoate.

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