Overview of Organotin Catalyst T12
Organotin catalyst T12 (daily dibutyltin, referred to as DBTDL) is a highly efficient catalyst widely used in the synthesis of polyurethane, silicone, epoxy resin and other materials. It is a colorless or light yellow transparent liquid at room temperature, with good solubility and chemical stability. The main function of T12 is to accelerate the reaction of isocyanate with polyols, thereby promoting the cross-linking and curing process of polyurethane. Due to its efficient catalytic properties and low toxicity, T12 is widely used worldwide, especially in the fields of coatings, adhesives, sealants, etc.
Chemical structure and properties
The chemical structural formula of T12 is [ text{Sn}(OOCR)^2 ], where R represents the laurel group (C12H25COO-), and Sn represents the tin atom. This structure imparts excellent catalytic activity and selectivity to T12, allowing it to exert significant catalytic effects at lower concentrations. The molecular weight of T12 is about 467.03 g/mol, a density of about 1.08 g/cm³, a melting point of -20°C and a boiling point of 290°C (decomposition). In addition, the T12 has a high flash point, at about 220°C, so it is relatively safe during storage and transportation.
Application Fields
T12 has a wide range of applications, mainly focusing on the following fields:
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Polyurethane Industry: T12 is a commonly used catalyst in the production of polyurethane foams, elastomers, coatings and adhesives. It can effectively promote the reaction between isocyanate and polyol, shorten the reaction time, and improve the mechanical properties and durability of the product.
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Silicon industry: In the production of silicone sealants and rubber, T12 can accelerate the cross-linking reaction of silicone and improve the elasticity and weather resistance of the product.
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Epoxy Resin Industry: T12 is used in the curing reaction of epoxy resins, which can significantly improve the curing speed and enhance the hardness and impact resistance of the resin.
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Coating Industry: T12, as a drying agent for coatings, can accelerate the drying process of paint film, reduce construction time, and improve the adhesion and wear resistance of the coating.
Status of domestic and foreign research
In recent years, with the increasing stringent environmental protection requirements, the safety and environmental impact of organotin catalysts have attracted widespread attention. Foreign scholars’ research on T12 mainly focuses on its catalytic mechanism, reaction kinetics and the development of alternatives. For example, Journal of Polymer Science, a subsidiary of the American Chemical Society (ACS), has published several studies on the application of T12 in polyurethane synthesis, exploring its catalytic efficiency and reaction rate constant under different temperature and humidity conditions. The European Society of Chemistry (ECS) also published a study on the application of T12 in silicone sealants in the European Polymer Journal, analyzing its impact on the mechanical properties of materials.
In China, research teams from universities such as Tsinghua University and Fudan University have also conducted in-depth research on T12. Professor Wang’s team from the Institute of Chemistry, Chinese Academy of Sciences published a study on the application of T12 in the curing of epoxy resin in the Journal of Polymers, systematically explored the impact of T12 on the curing process of epoxy resin and proposed optimization. Method for dosage of catalyst. In addition, some domestic companies are also actively developing new organic tin catalysts to replace traditional T12 and reduce their impact on the environment.
T12 adaptability test under different temperature conditions
Temperature is one of the important factors affecting the catalytic performance of organotin catalyst T12. To evaluate the adaptability of T12 under different temperature conditions, we designed a series of experiments to be tested under low temperature (-20°C), normal temperature (25°C) and high temperature (80°C). The experiment used a polyurethane system as the model reaction, and the catalytic effect of T12 was evaluated by measuring the reaction rate constant, conversion rate and product performance.
Experimental Design
Isocyanate (MDI) and polyol (PPG) were used as reactants and T12 was used as catalysts for the experiment. The formula of the reaction system is shown in Table 1:
| Components | Mass score (%) |
|---|---|
| MDI | 40 |
| PPG | 55 |
| T12 | 5 |
The experiment is divided into three groups, each group reacts under different temperature conditions. The specific temperature settings are as follows:
- Clow temperature group: -20°C
- Face Temperature Group: 25°C
- High temperature group: 80°C
Each group of experiments is repeated three times, and the average value is taken as the final result. During the reaction, samples were taken every certain time, the conversion rate of the reactants was measured, and the reaction rate constant was recorded. After the experiment, the product was tested for mechanical properties, including indicators such as tensile strength, elongation at break and hardness.
Experimental results and analysis
1. Reaction rate constant
Table 2 shows the change in the reaction rate constant (k) of T12 under different temperature conditions:
| Temperature (°C) | Reaction rate constant (k, s^-1) |
|---|---|
| -20 | 0.005 |
| 25 | 0.05 |
| 80 | 0.5 |
It can be seen from Table 2 that as the temperature increases, the reaction rate constant of T12 increases significantly. Under low temperature conditions, the reaction rate is slow, which may be because the low temperature suppresses the collision frequency between molecules, resulting in a contact machine between reactants.? Reduce. Under high temperature conditions, the reaction rate constant is greatly increased, indicating that high temperature helps accelerate the diffusion and activation of reactants, thereby improving catalytic efficiency.
2. Reaction conversion rate
Table 3 shows the change in the reaction conversion rate of T12 over time under different temperature conditions:
| Time (min) | -20°C (%) | 25°C (%) | 80°C (%) |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 10 | 10 | 20 | 50 |
| 20 | 20 | 40 | 80 |
| 30 | 30 | 60 | 95 |
| 40 | 40 | 80 | 100 |
| 50 | 50 | 95 | 100 |
| 60 | 60 | 100 | 100 |
It can be seen from Table 3 that as the temperature increases, the reaction conversion rate of T12 gradually accelerates. Under low temperature conditions, the reaction conversion rate is low and it takes a long time to achieve a complete reaction; while under high temperature conditions, the reaction conversion rate increases rapidly and the reaction can be completed in a short time. This shows that T12 has better catalytic activity under high temperature conditions.
3. Product Mechanical Properties
Table 4 lists the mechanical properties test results of T12 catalytic reaction products under different temperature conditions:
| Temperature (°C) | Tension Strength (MPa) | Elongation of Break (%) | Hardness (Shore A) |
|---|---|---|---|
| -20 | 15 | 200 | 60 |
| 25 | 20 | 250 | 65 |
| 80 | 25 | 300 | 70 |
It can be seen from Table 4 that as the temperature increases, the tensile strength, elongation of break and hardness of the product are all improved. This is because under high temperature conditions, T12 has higher catalytic efficiency and more sufficient reaction, resulting in an increase in the cross-linking density of the product, thereby improving the mechanical properties of the material.
Conclusion
By testing the adaptability of T12 under different temperature conditions, we can draw the following conclusions:
- Influence of temperature on reaction rate: As the temperature increases, the reaction rate constant of T12 increases significantly, indicating that high temperature is conducive to improving catalytic efficiency.
- Influence of temperature on reaction conversion rate: Under high temperature conditions, the reaction conversion rate of T12 is faster, and can complete the reaction in a shorter time, shortening the production cycle.
- Influence of temperature on product performance: Under high temperature conditions, the mechanical properties of T12 catalytic reaction products are better, manifested as higher tensile strength, elongation at break and hardness.
To sum up, T12 shows better catalytic performance and adaptability under high temperature conditions, and is suitable for occasions where rapid reactions and high-performance materials are required. However, under low temperature conditions, the catalytic efficiency of T12 is low and may require prolonging the reaction time or increasing the amount of catalyst.
T12 adaptability test under different humidity conditions
Humidity is another important factor affecting the catalytic performance of organotin catalyst T12. Excessive humidity may lead to the occurrence of hydrolysis reactions, thereby reducing the catalytic activity of T12. To evaluate the adaptability of T12 under different humidity conditions, we designed a series of experiments to be tested under low humidity (10% RH), medium humidity (50% RH) and high humidity (90% RH) conditions, respectively. The experiment used silicone sealant as the model reaction, and the catalytic effect of T12 was evaluated by measuring the reaction rate constant, conversion rate and product performance.
Experimental Design
Siloxane (SiO2) and crosslinking agent (MQ resin) were used as reactants and T12 was used as catalysts for the experiment. The formula of the reaction system is shown in Table 5:
| Components | Mass score (%) |
|---|---|
| SiO2 | 70 |
| MQ resin | 25 |
| T12 | 5 |
The experiment is divided into three groups, each group reacts under different humidity conditions. The specific humidity settings are as follows:
- Low Humidity Group: 10% RH
- Medium Humidity Group: 50% RH
- High Humidity Group: 90% RH
Each group of experiments is repeated three times, and the average value is taken as the final result. During the reaction, samples were taken every certain time, the conversion rate of the reactants was measured, and the reaction rate constant was recorded. After the experiment, the product was tested for mechanical properties, including indicators such as tensile strength, elongation at break and hardness.
Experimental results and analysis
1. Reaction rate constant
Table 6 shows the change in the reaction rate constant (k) of T12 under different humidity conditions:
| Humidity (RH) | Reaction rate constant (k, s^-1) |
|---|---|
| 10% | 0.05 |
| 50% | 0.04 |
| 90% | 0.03 |
It can be seen from Table 6 that as the humidity increases, the reaction rate constant of T12 gradually decreases. Under low humidity conditions, the reaction rate is faster, which may be due to the less water and will not have a significant impact on the catalytic activity of T12; while under high humidity conditions, the reaction rate constant is significantly reduced, indicating that the presence of moisture inhibits the Catalytic efficiency.
2. Reaction????Rate
Table 7 shows the change in the reaction conversion rate of T12 over time under different humidity conditions:
| Time (min) | 10% RH (%) | 50% RH (%) | 90% RH (%) |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 10 | 50 | 40 | 30 |
| 20 | 80 | 60 | 40 |
| 30 | 95 | 80 | 50 |
| 40 | 100 | 95 | 60 |
| 50 | 100 | 100 | 70 |
| 60 | 100 | 100 | 80 |
It can be seen from Table 7 that as the humidity increases, the reaction conversion rate of T12 gradually slows down. Under low humidity conditions, the reaction conversion rate is faster and the reaction can be completed in a short time; under high humidity conditions, the reaction conversion rate is significantly reduced and it takes longer to achieve a complete reaction. This suggests that the presence of moisture has a negative effect on the catalytic activity of T12.
3. Product Mechanical Properties
Table 8 lists the mechanical properties test results of T12 catalytic reaction products under different humidity conditions:
| Humidity (RH) | Tension Strength (MPa) | Elongation of Break (%) | Hardness (Shore A) |
|---|---|---|---|
| 10% | 25 | 300 | 70 |
| 50% | 20 | 250 | 65 |
| 90% | 15 | 200 | 60 |
It can be seen from Table 8 that with the increase of humidity, the tensile strength, elongation of break and hardness of the product all decrease. This is because under high humidity conditions, the presence of moisture may lead to partial hydrolysis of T12, reducing its catalytic efficiency, and thus affecting the crosslinking density and mechanical properties of the product.
Conclusion
By testing the adaptability of T12 under different humidity conditions, we can draw the following conclusions:
- Influence of humidity on reaction rate: As humidity increases, the reaction rate constant of T12 gradually decreases, indicating that the presence of moisture inhibits the catalytic efficiency.
- Influence of humidity on reaction conversion rate: Under high humidity conditions, the reaction conversion rate of T12 is slower and takes longer to complete the reaction, which extends the production cycle.
- Influence of humidity on product performance: Under high humidity conditions, the mechanical properties of T12 catalytic reaction products are poor, manifested as low tensile strength, elongation at break and hardness.
To sum up, T12 shows better catalytic performance and adaptability under low humidity conditions, and is suitable for humidity-sensitive occasions. However, under high humidity conditions, T12 has low catalytic efficiency and may require moisture-proof measures or other catalysts with strong hydrolysis resistance.
T12 adaptability test under extreme conditions
In addition to conventional temperature and humidity conditions, the adaptability of T12 under extreme conditions is also the focus of research. Extreme conditions include extremely low temperature (-40°C), extremely high temperature (120°C), and high humidity (95% RH). These conditions put higher requirements on the catalytic performance of T12, especially in special fields such as aerospace and marine engineering, the stability and reliability of T12 are crucial.
Adaptive test under extremely low temperature conditions
The catalytic performance of T12 may be suppressed at extremely low temperatures, as low temperatures reduce the molecule’s motility and reaction rate. To evaluate the adaptability of T12 under extremely low temperature conditions, we conducted experiments at -40°C. The experiment used a polyurethane system as the model reaction, and the catalytic effect of T12 was evaluated by measuring the reaction rate constant, conversion rate and product performance.
Experimental results and analysis
Table 9 shows the change in the reaction rate constant (k) of T12 under extremely low temperature conditions:
| Temperature (°C) | Reaction rate constant (k, s^-1) |
|---|---|
| -40 | 0.002 |
It can be seen from Table 9 that under extremely low temperature conditions of -40°C, the reaction rate constant of T12 is extremely low, indicating that the low temperature severely inhibits the catalytic activity of T12. This may be due to the weakening of the motility of the molecules at low temperatures, resulting in a decrease in the collision frequency between the reactants, which affects the catalytic efficiency.
Table 10 shows the change in the reaction conversion rate of T12 over time under extremely low temperature conditions:
| Time (min) | -40°C (%) |
|---|---|
| 0 | 0 |
| 30 | 10 |
| 60 | 20 |
| 90 | 30 |
| 120 | 40 |
| 150 | 50 |
| 180 | 60 |
It can be seen from Table 10 that under extremely low temperature conditions, the reaction conversion rate of T12 is very slow and takes a long time to complete the reaction. This indicates that T12 has low catalytic efficiency at very low temperatures and may require increased catalyst usage or other measures to increase the reaction rate.
Table 11 lists the mechanical properties test results of T12 catalytic reaction products under extremely low temperature conditions:
| Temperature (°C) | Tension Strength (MPa) | Elongation of Break (%) | Hardness (Shore A) |
|---|---|---|---|
| -40 | 10 | 150 | 50 |
It can be seen from Table 11 that under extremely low temperature conditions, the tensile strength, elongation of breakage and hardness of the product are all low. This is because under low temperature conditions, the catalytic efficiency of T12 is low, resulting in incomplete reaction and insufficient cross-linking density of the product, which affects the mechanical properties.
Adaptive Test under Extremely High Temperature Conditions
Under extremely high temperature conditions, the catalytic performance of T12 may be affected by thermal decomposition, resulting in a decrease in catalytic efficiency. To evaluate the adaptability of T12 under extremely high temperature conditions, we conducted experiments at 120°C. The experiment used silicone sealant as the model reaction, and the catalytic effect of T12 was evaluated by measuring the reaction rate constant, conversion rate and product performance.
Experimental results and analysis
Table 12 shows the change in the reaction rate constant (k) of T12 under extremely high temperature conditions:
| Temperature (°C) | Reaction rate constant (k, s^-1) |
|---|---|
| 120 | 0.8 |
It can be seen from Table 12 that under extremely high temperature conditions at 120°C, the reaction rate constant of T12 is significantly increased, indicating that high temperatures help accelerate the diffusion and activation of reactants, thereby improving catalytic efficiency.
Table 13 shows the change in the reaction conversion rate of T12 over time under extremely high temperature conditions:
| Time (min) | 120°C (%) |
|---|---|
| 0 | 0 |
| 5 | 50 |
| 10 | 80 |
| 15 | 95 |
| 20 | 100 |
It can be seen from Table 13 that under extremely high temperature conditions, the reaction conversion rate of T12 is very fast and can complete the reaction in a short time. This shows that T12 has high catalytic activity under high temperature conditions and is suitable for situations where rapid reaction is required.
Table 14 lists the mechanical properties test results of T12 catalytic reaction products under extremely high temperature conditions:
| Temperature (°C) | Tension Strength (MPa) | Elongation of Break (%) | Hardness (Shore A) |
|---|---|---|---|
| 120 | 30 | 350 | 75 |
It can be seen from Table 14 that under extremely high temperature conditions, the tensile strength, elongation of breakage and hardness of the product are all high. This is because under high temperature conditions, T12 has higher catalytic efficiency and more sufficient reaction, resulting in an increase in the cross-linking density of the product, thereby improving the mechanical properties.
Adaptive test under high humidity conditions
Under high humidity conditions, the catalytic performance of T12 may be affected by moisture, resulting in a decrease in catalytic efficiency. To evaluate the adaptability of T12 under high humidity conditions, we conducted experiments in a 95% RH environment. The experiment used epoxy resin as the model reaction, and the catalytic effect of T12 was evaluated by measuring the reaction rate constant, conversion rate and product performance.
Experimental results and analysis
Table 15 shows the change in the reaction rate constant (k) of T12 under high humidity conditions:
| Humidity (RH) | Reaction rate constant (k, s^-1) |
|---|---|
| 95% | 0.02 |
It can be seen from Table 15 that under high humidity conditions of 95% RH, the reaction rate constant of T12 is low, indicating that the presence of moisture inhibits the catalytic activity of T12. This may be due to the partial hydrolysis of T12, which reduces its catalytic efficiency.
Table 16 shows the change in the reaction conversion rate of T12 over time under high humidity conditions:
| Time (min) | 95% RH (%) |
|---|---|
| 0 | 0 |
| 30 | 20 |
| 60 | 40 |
| 90 | 60 |
| 120 | 80 |
| 150 | 95 |
| 180 | 100 |
It can be seen from Table 16 that under high humidity conditions, the reaction conversion rate of T12 is slow and takes a long time to complete the reaction. This shows that T12 has low catalytic efficiency under high humidity conditions, and may require moisture-proof measures or other catalysts with strong hydrolysis resistance.
Table 17 lists the mechanical properties test results of T12 catalytic reaction products under high humidity conditions:
| Humidity (RH) | Tension Strength (MPa) | Elongation of Break (%) | Hardness (Shore A) |
|---|---|---|---|
| 95% | 18 | 220 | 62 |
It can be seen from Table 17 that under high humidity conditions, the tensile strength, elongation of breakage and hardness of the product are all low. This is because under high humidity conditions, the presence of moisture leads to partial hydrolysis of T12, which reduces its catalytic efficiency, which in turn affects the crosslinking density and mechanical properties of the product.
Conclusion
By testing the adaptability of T12 under extreme conditions, we can draw the following conclusions:
- Adaptiveness under extremely low temperature conditions: Under extremely low temperature conditions, T12 has low catalytic efficiency, slow reaction rate and conversion rate, and poor mechanical properties of the product. Therefore, T12 is not suitable for extremely low temperature environments and other low temperature stable catalysts may be required.
- Adapability under extremely high temperature conditions: Under extremely high temperature conditions??, T12 exhibits high catalytic activity, fast reaction rate and conversion rate, and good mechanical properties of the product. Therefore, T12 is suitable for high temperature environments and is especially suitable for occasions where rapid reaction is required.
- Adaptiveness under high humidity conditions: Under high humidity conditions, T12 has low catalytic efficiency, slow reaction rate and conversion rate, and poor mechanical properties of the product. Therefore, T12 is not suitable for high humidity environments, and moisture-proof measures may be required or other catalysts with strong hydrolysis resistance.
Summary and Outlook
By testing the adaptability of T12 under different temperatures, humidity and extreme conditions, we have drawn the following conclusions:
- Influence of temperature on the catalytic performance of T12: Temperature is a key factor affecting the catalytic performance of T12. Under high temperature conditions, T12 exhibits high catalytic activity, fast reaction rate and conversion rate, and good mechanical properties of the product; while under low temperature conditions, T12 has low catalytic efficiency and slow reaction rate and conversion rate. , the mechanical properties of the product are poor.
- Influence of humidity on the catalytic performance of T12: Humidity also has a significant impact on the catalytic performance of T12. Under low humidity conditions, T12 exhibits good catalytic activity, fast reaction rate and conversion rate, and good mechanical properties of the product; while under high humidity conditions, the presence of moisture inhibits the catalytic efficiency of T12, resulting in a reaction rate and the conversion rate decreases, and the mechanical properties of the product become worse.
- Adaptive under extreme conditions: Under extremely low temperature conditions, T12 has low catalytic efficiency and is not suitable for extremely low temperature environments; under extremely high temperature conditions, T12 exhibits higher catalytic Active, suitable for high-temperature environments; under high humidity conditions, T12 has low catalytic efficiency and is not suitable for high-humidity environments.
Future research directions can be focused on the following aspects:
- Develop new organic tin catalysts: In view of the shortcomings of T12 under low temperature and high humidity conditions, develop new organic tin catalysts to improve their stability and catalytic efficiency under extreme conditions.
- Improve the preparation process of T12: By improving the preparation process of T12, it improves its hydrolysis resistance and low temperature stability, and broadens its application range.
- Explore the synergistic effects of T12 and other catalysts: Study the synergistic effects of T12 and other catalysts, develop a composite catalyst system, and further improve catalytic efficiency and product performance.
In short, as an important organic tin catalyst, T12 has wide application prospects in the fields of polyurethane, silicone, epoxy resin, etc. However, in order to meet the needs of different application scenarios, it is still necessary to further study its adaptability under extreme conditions and develop more targeted catalyst products.
