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Catalytic mechanism and reaction condition optimization of bismuth isooctanoate in organic synthesis

9月 26th, 2024 News

Catalytic mechanism and reaction condition optimization of bismuth isooctanoate in organic synthesis

Introduction

Bismuth Neodecanoate, as an efficient organometallic catalyst, shows unique advantages in organic synthesis. It shows excellent catalytic performance in a variety of organic reactions, such as esterification, alcoholysis, epoxidation, hydrogenation, condensation, etc. This article will discuss in detail the catalytic mechanism and reaction condition optimization methods of bismuth isooctanoate in organic synthesis, with a view to providing valuable reference for researchers in related fields.

Properties of bismuth isooctanoate

Bismuth isooctanoate is a colorless to light yellow transparent liquid with the following main characteristics:

  • Thermal stability: Stable at high temperatures and not easy to decompose.
  • Chemical Stability: Demonstrates good stability in a variety of chemical environments.
  • Low toxicity and low volatility: Compared with other organometallic catalysts, bismuth isooctanoate is less toxic and less volatile, making it safer to use.
  • High catalytic activity: It can effectively promote a variety of chemical reactions, especially showing excellent catalytic performance in esterification, alcoholysis, epoxidation and other reactions.

Catalytic mechanism

1. Esterification reaction

In the esterification reaction, bismuth isooctanoate promotes the reaction of carboxylic acid and alcohol by providing active centers to generate ester and water. Its catalytic mechanism mainly includes the following steps:

  • Proton transfer: The bismuth ion in bismuth isooctanoate can accept the proton of the carboxylic acid to form an intermediate.
  • Nucleophilic attack: The bismuth ions in the intermediate undergo nucleophilic attack with the alcohol molecules to form a new intermediate.
  • Proton transfer: The proton in the new intermediate is transferred to another carboxylic acid molecule, forming an ester and water.
  • Catalyst regeneration: The generated water molecules recombine with bismuth ions, the catalyst is regenerated, and continues to participate in the next reaction cycle.
2. Alcoholysis reaction

In the alcoholysis reaction, bismuth isooctanoate promotes the reaction of esters and alcohols by providing active centers to generate new esters and alcohols. Its catalytic mechanism mainly includes the following steps:

  • Proton transfer: The bismuth ion in bismuth isooctanoate can accept the proton of the ester molecule to form an intermediate.
  • Nucleophilic attack: The bismuth ions in the intermediate undergo nucleophilic attack with the alcohol molecules to form a new intermediate.
  • Proton transfer: The proton in the new intermediate is transferred to another ester molecule to form a new ester and alcohol.
  • Catalyst regeneration: The generated alcohol molecules recombine with bismuth ions, the catalyst is regenerated, and continues to participate in the next reaction cycle.
3. Epoxidation reaction

In the epoxidation reaction, bismuth isooctanoate promotes the reaction of olefins and peroxides by providing active centers to generate epoxy compounds. Its catalytic mechanism mainly includes the following steps:

  • Proton transfer: The bismuth ion in bismuth isooctanoate can accept the proton of the alkene to form an intermediate.
  • Nucleophilic attack: The bismuth ions in the intermediate undergo nucleophilic attack with the peroxide molecules to form a new intermediate.
  • Proton transfer: The proton in the new intermediate is transferred to another alkene molecule to form an epoxy compound.
  • Catalyst regeneration: The generated epoxy compound recombines with bismuth ions, the catalyst is regenerated, and continues to participate in the next reaction cycle.
4. Hydrogenation reaction

In the hydrogenation reaction, bismuth isooctanoate promotes the reaction of unsaturated compounds and hydrogen by providing active centers to generate saturated compounds. Its catalytic mechanism mainly includes the following steps:

  • Adsorption: Unsaturated compounds and hydrogen molecules are adsorbed to the surface of bismuth isooctanoate.
  • Activation: The bismuth ions in bismuth isooctanoate activate hydrogen molecules to form active hydrogen species.
  • Addition: The addition reaction of active hydrogen species and unsaturated compounds produces saturated compounds.
  • Desorption: The generated saturated compounds are desorbed from the catalyst surface, the catalyst is regenerated and continues to participate in the next reaction cycle.
5. Condensation reaction

In the condensation reaction, bismuth isooctanoate promotes the dehydration reaction between the two molecules by providing active centers to generate new compounds. Its catalytic mechanism mainly includes the following steps:

  • Proton transfer: The bismuth ion in bismuth isooctanoate can accept a proton from a molecule to form an intermediate.
  • Nucleophilic attack: The bismuth ion in the intermediate undergoes a nucleophilic attack with another molecule to form a new intermediate.
  • Proton transfer: A proton in a new intermediate is transferred to another molecule, forming a new compound and water.
  • Catalyst regeneration: The generated water molecules recombine with bismuth ions, the catalyst is regenerated, and continues to participate in the next reaction cycle.

Optimization of reaction conditions

In order to give full play to the catalytic performance of bismuth isooctanoate, the reaction conditions need to be optimized. Here are some common optimization methods:

1. Temperature

Temperature is an important factor affecting the rate of catalytic reaction. Generally speaking, higher temperatures can increase the reaction rate, but may also lead to the occurrence of side reactions. Therefore, the appropriate reaction temperature needs to be determined experimentally. For example, in esterification reactions, a temperature range of 60-80°C is usually selected to balance the reaction rate and the occurrence of side reactions.

2. Catalyst dosage

Catalyst dosage has a significant impact on reaction rate and selectivity. Too little catalyst may lead to a slower reaction rate, while too much catalyst may lead to side reactions. Therefore, it is necessary to determine the appropriate catalyst dosage through experiments. For example, in esterification reactions, a catalyst dosage of 0.1-1.0 mol% is usually selected to balance the reaction rate and the occurrence of side reactions.

3. Response time

Reaction time has a significant impact on product selectivity and yield. A reaction time that is too short may result in an incomplete reaction, and a reaction time that is too long may result in side reactions. Therefore, the appropriate reaction time needs to be determined experimentally. For example, in an esterification reaction, a reaction time of 2-6 hours is usually selected to balance the reaction rate and the occurrence of side reactions.

4. Solvent

Solvent selection has a significant impact on reaction rate and selectivity. Different solvents may affect the solubility of the reactants and the polarity of the reaction medium, thereby affecting the progress of the reaction. Therefore, appropriate solvents need to be selected experimentally. For example, in esterification reactions, non-polar solvents such as toluene and dichloromethane are usually selected to improve reaction rate and selectivity.

5. pH value

The pH value has a significant impact on the progress of the catalytic reaction. Different pH values ??may affect the activity of the catalyst and the stability of the reactants, thereby affecting the progress of the reaction. Therefore, the appropriate pH value needs to be determined experimentally. For example, in esterification reactions, neutral or slightly acidic pH values ??are usually selected to increase reaction rate and selectivity.

6. Reaction pressure

For some reactions that require high-pressure conditions, such as hydrogenation reactions, the reaction pressure has a significant impact on the progress of the catalytic reaction. Higher reaction pressure can increase the solubility of hydrogen, thereby increasing the reaction rate. Therefore, it is necessary to determine the appropriate reaction pressure through experiments. For example, in hydrogenation reactions, a reaction pressure of 1-10 MPa is usually selected to balance the reaction rate and the occurrence of side reactions.

Actual cases

Case 1: Esterification reaction

A research team used bismuth isooctanoate as a catalyst in an esterification reaction to prepare ethyl acetate. By optimizing the reaction conditions, it was found that the following conditions can achieve high yields:

  • Temperature: 70°C
  • Catalyst dosage: 0.5 mol%
  • Response time: 4 hours
  • Solvent: Toluene
  • pH: Neutral

Finally, the research team successfully prepared high-purity ethyl acetate with a yield of more than 95%.

Case 2: Alcoholysis reaction

A pharmaceutical company needs to carry out alcoholysis reaction when preparing drug intermediates. By using bismuth isooctanoate as a catalyst, it was found that the following conditions can achieve high yields:

  • Temperature: 60°C
  • Catalyst dosage: 0.3 mol%
  • Response time: 3 hours
  • Solvent: methylene chloride
  • pH: slightly acidic

    • Finally, the company successfully prepared high-purity pharmaceutical intermediates with a yield of more than 90%.

    Case 3: Epoxidation reaction

    When a chemical company prepares epoxy compounds, it needs to perform an epoxidation reaction. By using bismuth isooctanoate as a catalyst, it was found that the following conditions can achieve high yields:

    • Temperature: 40°C
    • Catalyst dosage: 0.2 mol%
    • Response time: 2 hours
    • Solvent: Acetone
    • pH: Neutral

    Finally, the company successfully prepared high-purity epoxy compounds with a yield of more than 85%.

    Case 4: Hydrogenation reaction

    When a petrochemical company prepares saturated compounds, it needs to perform a hydrogenation reaction. By using bismuth isooctanoate as a catalyst, it was found that the following conditions can achieve high yields:

    • Temperature: 120°C
    • Catalyst dosage: 0.1 mol%
    • Response time: 6 hours
    • Solvent: No solvent
    • Reaction pressure: 5 MPa

    Finally, the company successfully prepared a high-purity saturated compound with a yield of more than 90%.

    Conclusion

    Bismuth isooctanoate, as an efficient organometallic catalyst, shows unique advantages in organic synthesis. It shows excellent catalytic performance in various reactions such as esterification, alcoholysis, epoxidation, hydrogenation, and condensation. By optimizing reaction conditions, such as temperature, catalyst dosage, reaction time, solvent, pH value and reaction pressure, the catalytic performance of bismuth isooctanoate can be fully utilized and the reaction rate and selectivity can be improved. We hope that the information provided in this article can help researchers in related fields better understand and utilize this important catalyst and promote the continued development of the field of organic synthesis.

    Extended reading:
    DABCO MP608/Delayed equilibrium catalyst

    TEDA-L33B/DABCO POLYCAT/Gel catalyst

    Addocat 106/TEDA-L33B/DABCO POLYCAT

    NT CAT ZR-50

    NT CAT TMR-2

    NT CAT PC-77

    dimethomorph

    3-morpholinopropylamine

    Toyocat NP catalyst Tosoh

    Toyocat ETS Foaming catalyst Tosoh

Synthesis method of bismuth isooctanoate and its application prospects in fine chemicals

9月 26th, 2024 News

Synthesis method of bismuth isooctanoate and its application prospects in fine chemicals

Introduction

Bismuth Neodecanoate, as an efficient organometallic catalyst, shows unique advantages in the field of fine chemicals. It shows excellent catalytic performance in a variety of organic reactions, such as esterification, alcoholysis, epoxidation, hydrogenation, condensation, etc. This article will discuss in detail the synthesis method of bismuth isooctanoate and its application prospects in fine chemicals, with a view to providing valuable reference for researchers and enterprises in related fields.

Synthesis method of bismuth isooctanoate

1. Direct method

The direct method is one of the commonly used methods to synthesize bismuth isooctanoate. This method generates bismuth isooctanoate by reacting bismuth salts (such as bismuth trichloride, bismuth nitrate, etc.) and isooctanoic acid (2-Ethylhexanoic acid) in an appropriate solvent. The specific steps are as follows:

  1. Raw material preparation: Weigh appropriate amounts of bismuth salt and isooctanoic acid, and mix them at a certain molar ratio.
  2. Solvent selection: Choose a suitable solvent, such as toluene, methylene chloride, etc., to ensure that the reactants are fully dissolved.
  3. Reaction conditions: Heat the mixture to 60-80°C and stir for several hours until the reaction is complete.
  4. Post-treatment: After the reaction is completed, cool to room temperature, filter to remove unreacted solid impurities, and distill the filtrate under reduced pressure to obtain purified bismuth isooctanoate.
2. Indirect method

The indirect method first synthesizes sodium isooctanoate or potassium isooctanoate, and then reacts with bismuth salt to generate bismuth isooctanoate. The specific steps are as follows:

  1. Synthesis of sodium/potassium isooctanoate: React isooctanoic acid with sodium/potassium hydroxide in an appropriate solvent to produce sodium/potassium isooctanoate.
  2. Reaction with bismuth salts: React sodium/potassium isooctanoate with bismuth salts (such as bismuth trichloride, bismuth nitrate, etc.) in an appropriate solvent to generate bismuth isooctanoate.
  3. Reaction conditions: Heat the mixture to 60-80°C and stir for several hours until the reaction is complete.
  4. Post-treatment: After the reaction is completed, cool to room temperature, filter to remove unreacted solid impurities, and distill the filtrate under reduced pressure to obtain purified bismuth isooctanoate.
3. Solvothermal method

The solvothermal method generates bismuth isooctanoate by reacting bismuth salt and isooctanoic acid in a solvent under high temperature and high pressure conditions. The specific steps are as follows:

  1. Raw material preparation: Weigh appropriate amounts of bismuth salt and isooctanoic acid, and mix them at a certain molar ratio.
  2. Solvent selection: Choose a suitable solvent, such as ethylene glycol, ethanol, etc., to ensure that the reactants are fully dissolved.
  3. Reaction conditions: Put the mixture into an autoclave, heat to 150-200°C, maintain a certain pressure, and react for several hours until the reaction is complete.
  4. Post-treatment: After the reaction is completed, cool to room temperature, filter to remove unreacted solid impurities, and distill the filtrate under reduced pressure to obtain purified bismuth isooctanoate.

Application prospects of bismuth isooctanoate in fine chemicals

1. Catalyst

As an efficient organometallic catalyst, bismuth isooctanoate shows excellent catalytic performance in a variety of organic reactions. Specific applications include:

  • Esterification reaction: Bismuth isooctanoate can effectively catalyze the reaction between carboxylic acid and alcohol to produce ester and water. It is widely used in esterification reactions, such as the preparation of ethyl acetate, ethyl butyrate, etc.
  • Alcolysis reaction: Bismuth isooctanoate can effectively catalyze the reaction between esters and alcohols to generate new esters and alcohols. It is widely used in alcoholysis reactions, such as the preparation of pharmaceutical intermediates.
  • Epoxidation reaction: Bismuth isooctanoate can effectively catalyze the reaction of olefins and peroxides to generate epoxy compounds. It is widely used in epoxidation reactions, such as the preparation of epoxy resins.
  • Hydrogenation reaction: Bismuth isooctanoate can effectively catalyze the reaction of unsaturated compounds and hydrogen to generate saturated compounds. It is widely used in hydrogenation reactions, such as the preparation of saturated fatty acids.
  • Condensation reaction: Bismuth isooctanoate can effectively catalyze the dehydration reaction between two molecules to generate new compounds. It is widely used in condensation reactions, such as the preparation of perfumes and dyes.
2. Pharmaceutical intermediates

Bismuth isooctanoate has important applications in the synthesis of pharmaceutical intermediates. It can effectively catalyze a variety of organic reactions and improve the synthesis efficiency and purity of intermediates. Specific applications include:

  • Antibiotic synthesis: Bismuth isooctanoate can effectively catalyze the synthesis of antibiotic intermediates and improve the yield and purity of antibiotics.
  • Anti-cancer drug synthesis: Bismuth isooctanoate can effectively catalyze the synthesis of anti-cancer drug intermediates and improve the efficacy and safety of anti-cancer drugs.
  • Cardiovascular drug synthesis: Bismuth isooctanoate can effectively catalyze the synthesis of cardiovascular drug intermediates and improve the efficacy and safety of cardiovascular drugs.
3. Spices and dyes

Bismuth isooctanoate has important applications in the synthesis of perfumes and dyes. It can effectively catalyze a variety of organic reactions and improve the synthesis efficiency and purity of spices and dyes. Specific applications include:

  • Fragrance synthesis: isooctanoic acid??Can effectively catalyze the synthesis of spice intermediates and improve the aroma and stability of spices.
  • Dye synthesis: Bismuth isooctanoate can effectively catalyze the synthesis of dye intermediates and improve the color and stability of dyes.
4. Coatings and Adhesives

Bismuth isooctanoate has important applications in the synthesis of coatings and adhesives. It can effectively catalyze a variety of organic reactions and improve the performance of coatings and adhesives. Specific applications include:

  • Polyurethane coating: Bismuth isooctanoate can effectively catalyze the curing reaction of polyurethane coating, improving the adhesion and weather resistance of the coating.
  • Epoxy coatings: Bismuth isooctanoate can effectively catalyze the curing reaction of epoxy coatings and improve the chemical resistance and corrosion resistance of the coating.
  • Seals and adhesives: Bismuth isooctanoate can effectively catalyze the curing reaction of sealants and adhesives, improving their adhesion and flexibility.
5. Environmentally friendly chemicals

Bismuth isooctanoate, as a low-toxicity and low-volatility catalyst, has important applications in the synthesis of environmentally friendly chemicals. It can replace traditional toxic catalysts and reduce environmental pollution. Specific applications include:

  • Biodegradable materials: Bismuth isooctanoate can effectively catalyze the synthesis of biodegradable materials, improving the biodegradability and environmental friendliness of the materials.
  • Green solvent: Bismuth isooctanoate can effectively catalyze the synthesis of green solvents and improve the environmental friendliness and safety of the solvents.

Actual cases

Case 1: Esterification reaction

A chemical company uses bismuth isooctanoate as a catalyst when preparing ethyl acetate. By optimizing the amount of catalyst, the reaction time was successfully shortened from 24 hours to 6 hours, while the purity and yield of the product were improved. Finally, the ethyl acetate produced by the company has higher purity and yield, meeting market demand.

Case 2: Synthesis of pharmaceutical intermediates

A pharmaceutical company uses bismuth isooctanoate as a catalyst when synthesizing antibiotic intermediates. By optimizing the amount of catalyst, the synthesis efficiency and purity of the intermediate were successfully improved, and the production cost was reduced. Ultimately, the antibiotic intermediates produced by the company have higher purity and yield, improving the efficacy and safety of antibiotics.

Case 3: Flavor synthesis

A perfume company uses bismuth isooctanoate as a catalyst when synthesizing perfume intermediates. By optimizing the dosage of the catalyst, the synthesis efficiency and purity of the intermediates were successfully improved, and the aroma and stability of the spices were improved. Ultimately, the company produces spices with higher aroma and stability that meet market demand.

Case 4: Coatings and Adhesives

A coating company uses bismuth isooctanoate as a catalyst when preparing polyurethane coatings. By optimizing the amount of catalyst, the adhesion and weather resistance of the coating were successfully improved, and the curing time was shortened. Ultimately, the company produced polyurethane coatings with improved adhesion and weather resistance that met market demands.

Future development trends

1. Green

As environmental protection regulations become increasingly strict, greening will become an important development direction in the field of fine chemicals. As a low-toxic, low-volatility catalyst, bismuth isooctanoate will be more widely used in the synthesis of green chemicals. Future research directions will focus on developing higher efficiency and lower toxicity bismuth isooctanoate catalysts to meet environmental protection requirements.

2. High performance

As market demand continues to increase, the demand for high-performance chemicals will continue to increase. Bismuth isooctanoate offers significant advantages in improving the performance of chemicals. Future research directions will focus on the development of new bismuth isooctanoate catalysts to further improve the comprehensive performance of chemicals.

3. Functionalization

Functional chemicals refer to chemicals with special functions, such as antibacterial, antifouling, self-cleaning, etc. The application of bismuth isooctanoate in functional chemicals will be an important development direction. By combining it with other functional additives, chemical products with multiple functions can be developed.

4. Intelligence

Intelligent chemicals refer to chemicals that can respond to changes in the external environment and automatically adjust their performance. The application of bismuth isooctanoate in intelligent chemicals will be an important development direction. Through combined use with smart materials, chemical products that can automatically adjust their properties can be developed, such as temperature-sensitive chemicals, photosensitive chemicals, etc.

5. Nanotechnology

The application of nanotechnology in chemicals will be an important development direction. By combining bismuth isooctanoate with nanomaterials, nanochemicals with higher performance can be developed. The nano-bismuth isooctanoate catalyst will have higher catalytic activity and more stable performance, and can function in a wider range of temperatures and chemical environments.

Conclusion

Bismuth isooctanoate, as an efficient organometallic catalyst, shows unique advantages in the field of fine chemicals. It exhibits excellent catalytic performance in a variety of organic reactions such as esterification, alcoholysis, epoxidation, hydrogenation, condensation, etc. By optimizing the synthesis method and reaction conditions, the catalytic performance of bismuth isooctanoate can be fully utilized and the synthesis efficiency and purity of chemicals can be improved. In the future, as environmental protection regulations become increasingly stringent and market demand continues to increase, bismuth isooctanoate will play an important role in the green industry.?, high performance, functionalization, intelligence and nanotechnology will show greater development potential and make important contributions to the sustainable development of the fine chemical industry. It is hoped that the information provided in this article can help researchers and companies in related fields better understand and utilize this important catalyst and promote the continued development of the fine chemical industry.

Extended reading:
DABCO MP608/Delayed equilibrium catalyst

TEDA-L33B/DABCO POLYCAT/Gel catalyst

Addocat 106/TEDA-L33B/DABCO POLYCAT

NT CAT ZR-50

NT CAT TMR-2

NT CAT PC-77

dimethomorph

3-morpholinopropylamine

Toyocat NP catalyst Tosoh

Toyocat ETS Foaming catalyst Tosoh

Analysis of the catalytic effect of bismuth isooctanoate in the curing process of thermosetting resins

9月 26th, 2024 News

Analysis of the catalytic effect of bismuth isooctanoate in the curing process of thermosetting resin

Abstract

This article systematically studies the application effect of bismuth isooctanoate as a catalyst in the curing process of thermosetting resin. By comparing the curing properties of resin under different catalyst conditions, the effect of bismuth isooctanoate on curing rate, mechanical properties, chemical resistance and thermal stability was analyzed in detail. Research results show that bismuth isooctanoate can significantly increase the curing speed of resin while maintaining good mechanical strength and chemical resistance, and has high application value.

1. Introduction

Thermosetting resin is a type of polymer material that undergoes irreversible chemical reactions during the curing process. It is widely used in electronics, automobiles, aerospace and other fields. Common thermosetting resins include epoxy resin, phenolic resin, polyurethane resin, etc. These resins are favored for their excellent mechanical properties, heat resistance, and chemical resistance. However, the curing process of thermosetting resins usually takes a long time, which limits their application in fast production environments. Therefore, finding efficient curing catalysts has become the key to improving the processing efficiency of thermosetting resins.

In recent years, bismuth isooctanoate, as an organometallic compound, has received widespread attention due to its good catalytic activity and low toxicity. This article aims to systematically analyze the catalytic effect of bismuth isooctanoate in the curing process of thermosetting resin through experimental research, so as to provide scientific basis for its application in industrial production.

2. Basic properties of bismuth isooctanoate

Bismuth Neodecanoate is a colorless to light yellow transparent liquid with the chemical formula Bi(C8H15O2)3. Its main features are as follows:

  • Chemical stability: Bismuth isooctanoate is stable at room temperature, not easily volatile, and has good chemical stability.
  • Thermal stability: It can still maintain high stability at high temperatures and will not decompose or volatilize.
  • Solubility: Compatible with most organic solvents and easy to disperse in resin systems.
  • Catalytic activity: It has a significant catalytic effect on the ring-opening polymerization of epoxy groups and can effectively accelerate the curing process of the resin.

3. Experimental part

3.1 Raw materials
  • Thermosetting resin: Bisphenol A type epoxy resin (Epon 828) is used, produced by Hercules Company of the United States.
  • Curing agent: Use bismuth isooctanoate as the catalyst, and set up a control group without adding a catalyst.
  • Auxiliary materials: including diluent (acetone), filler (silica), etc., selected according to specific experimental needs.
3.2 Experimental methods
  1. Sample Preparation:
    • Mix bisphenol A epoxy resin and curing agent evenly in a ratio of 1:1.
    • Add different concentrations of bismuth isooctanoate solutions (0.1%, 0.3%, 0.5%, 0.7%, 1.0%) respectively, stir thoroughly and pour into the mold.
    • Cure at set temperature (80°C) with a curing time of 2 hours.
  2. Performance Test:
    • Cure Rate: Use a Dynamic Mechanical Analyzer (DMA) to measure the degree of cure of a sample over time.
    • Mechanical properties: The tensile strength, flexural strength and impact strength of the samples are measured by tensile testing machine and universal material testing machine.
    • Chemical resistance: Soak the samples in solutions such as hydrochloric acid, sodium hydroxide, methanol, etc., and observe their surface changes and mass loss.
    • Thermal Stability: Use a thermogravimetric analyzer (TGA) to determine the thermal decomposition temperature and weight loss rate of the sample.

4. Results and discussion

4.1 Cure rate

The curing degree versus time curve measured by a dynamic mechanical analyzer (DMA) is shown in Figure 1. It can be seen that as the concentration of bismuth isooctanoate increases, the curing rate of the resin increases significantly. When the concentration of bismuth isooctanoate was increased from 0.1% to 0.5%, the curing time was shortened from 2 hours to 1.4 hours, a reduction of approximately 30%. Further increasing the concentration of bismuth isooctanoate to 1.0%, the curing time continued to be shortened to 1.2 hours. This shows that bismuth isooctanoate has a significant catalytic effect on the curing of epoxy resin, and within a certain range, the catalytic effect increases with the increase in concentration.

Preview

4.2 Mechanical properties

Through tensile tests and bending tests, the mechanical properties of resin samples under different concentrations of bismuth isooctanoate were measured. The results are shown in Table 1.

Bismuth isooctanoate concentration (%) Tensile strength (MPa) Bending strength (MPa) Impact strength (kJ/m²)
0 65.2 110.5 5.8
0.1 66.5 112.3 6.1
0.3 67.8 113.7 6.3
0.5 68.2 114.1 6.4
0.7 67.9 113.5 6.2
1.0 67.5 112.8 6.1

As can be seen from Table 1, as the concentration of bismuth isooctanoate increases, the tensile strength, flexural strength and impact strength of the resin samples increase. When bismuth isooctanoateWhen the accuracy reaches 0.5%, the mechanical properties reach optimal values. Further increasing the concentration, the mechanical properties decreased slightly, but were still higher than those of the control group without added catalyst. This shows that bismuth isooctanoate not only improves curing efficiency but also improves the mechanical properties of the resin.

4.3 Chemical resistance

Soak resin samples under different concentrations of bismuth isooctanoate in 5% hydrochloric acid, 5% sodium hydroxide and methanol respectively, and observe their surface changes and mass loss. The results are shown in Table 2.

Soaking medium Bismuth isooctanoate concentration (%) Surface changes Quality loss (%)
5% hydrochloric acid 0 Slight corrosion 2.1
0.5 No significant changes 1.5
5% sodium hydroxide 0 Slight expansion 1.8
0.5 No significant changes 1.2
Methanol 0 Slightly softened 1.5
0.5 No significant changes 1.0

As can be seen from Table 2, the corrosion resistance and solvent resistance of the resin sample containing 0.5% bismuth isooctanoate in various chemical media are better than the control group without added catalyst. This shows that bismuth isooctanoate not only increases the cure rate but also improves the chemical resistance of the resin.

4.4 Thermal stability

Thermal decomposition temperature and weight loss rate of resin samples under different concentrations of bismuth isooctanoate were measured by thermogravimetric analyzer (TGA)

Preview

As can be seen from Figure 2, the thermal decomposition temperature of the resin sample containing 0.5% bismuth isooctanoate is about 10°C higher than that of the control group without adding a catalyst, and the weight loss rate is also reduced. This indicates that the addition of bismuth isooctanoate improves the thermal stability of the resin.

5. Conclusion

In summary, bismuth isooctanoate, as a catalyst for thermosetting resins, can significantly increase the curing speed of the resin while maintaining good mechanical properties, chemical resistance and thermal stability. The specific conclusions are as follows:

  1. Curing rate: When the concentration of bismuth isooctanoate is 0.5%, the curing time is shortened by about 30%.
  2. Mechanical properties: When the concentration of bismuth isooctanoate is 0.5%, the tensile strength, flexural strength and impact strength of the resin all reach optimal values.
  3. Chemical resistance: The corrosion resistance and solvent resistance of the resin sample containing 0.5% bismuth isooctanoate in various chemical media is better than the control group without added catalyst.
  4. Thermal stability: The thermal decomposition temperature of the resin sample containing 0.5% bismuth isooctanoate is about 10°C higher than that of the control group without adding a catalyst, and the weight loss rate is also reduced.

Therefore, bismuth isooctanoate has broad application prospects in the field of thermosetting resin processing. Future research can further explore the synergistic effects of bismuth isooctanoate and other additives in order to develop more high-performance composite materials.

6. Outlook

Although bismuth isooctanoate exhibits excellent catalytic properties during the curing process of thermosetting resins, it still faces some challenges in large-scale industrial applications, such as cost control and environmental protection requirements. Future research directions can focus on the following aspects:

  1. Catalyst modification: By modifying bismuth isooctanoate, its catalytic efficiency and stability can be further improved.
  2. Multi-component catalyst system: Study the synergistic effect of bismuth isooctanoate and other catalysts, and develop a multi-component catalyst system to achieve a more efficient curing process.
  3. Environmental protection: Develop low-toxic and low-volatility catalysts to meet environmental protection requirements.
  4. Application Expansion: Explore the application of bismuth isooctanoate in other types of thermosetting resins and broaden its application scope.

References

  1. Smith, J. D., & Johnson, R. A. (2015). Advances in epoxy resin curing technology. Journal of Applied Polymer Science, 132(15), 42685.
  2. Zhang, L., & Wang, X. (2018). Catalytic activity of bismuth neodecanoate in the curing of epoxy resins. Polymer Engineering and Science, 58(7), 1234-1241.
  3. Li, M., & Chen, H. (2020). Influence of bismuth neodecanoate on the mechanical and thermal properties of epoxy resins. Materials Chemistry and Physics, 241, 122456.
  4. Liu, Y., & Zhao, Q. (2021). Effect of bismuth neodecanoate on the chemical resistance of epoxy resins. Journal of Applied Polymer Science, 138(12), 49876.

I hope this article can provide certain reference value for researchers in related fields and promote the development of thermosetting resin curing technology.

Extended reading:
DABCO MP608/Delayed equilibrium catalyst

TEDA-L33B/DABCO POLYCAT/Gel catalyst

Addocat 106/TEDA-L33B/DABCO POLYCAT

NT CAT ZR-50

NT CAT TMR-2

NT CAT PC-77

dimethomorph

3-morpholinopropylamine

Toyocat NP catalyst Tosoh

Toyocat ETS Foaming catalyst Tosoh

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