Preparation method and quality control of rubber additive dibutyltin dilaurate

Introduction

Dibutyltin dilaurate (DBTDL), as an efficient catalyst and stabilizer, is widely used in the rubber industry. This article will introduce in detail the preparation method of DBTDL and its quality control measures to ensure its performance and safety in rubber additives.

1. Preparation method of dibutyltin dilaurate

1. Raw material preparation
   • Dibutyltin oxide (DBTO): As a starting material, it is usually produced by the reaction of butanol and tin tetrachloride.
   • Lauric acid: As an acidic raw material, it is usually extracted from coconut oil or palm kernel oil.
2. Reaction Principle
   • The preparation of DBTDL is usually completed through the esterification reaction of dibutyltin oxide and lauric acid. The reaction equation is as follows:

     C8H17COOH+Bu2SnO→Bu2Sn(OCOCH11H23)2+H2O\text{C}_8\text{H}_{17}\text{COOH} + \text{Bu}_2\text{SnO} \rightarrow \text {Bu}_2\text{Sn}(\text{OCOCH}_{11}\text{H}_{23})_2 + \text{H}_2\text{O}C8 ​H17​COOH + Bu2 ​SnO→Bu 2​ Sn(OCOCH11​H23​) 2​+H2​O

3. Preparation Steps
   • Mixing of raw materials: Mix dibutyltin oxide and lauric acid in a certain proportion, usually the molar ratio is 1:2.
   • Heating reaction: Heat the mixture to 120-150°C with stirring. The reaction time is usually 2-4 hours.
   • Dehydration: The water produced during the reaction can be removed through a water separator to promote the reaction toward the product.
   • Cooling filtration: After the reaction is completed, cool the reaction mixture to room temperature and filter to remove insoluble matter.
   • Refining: The product is further purified through methods such as distillation or extraction to remove residual raw materials and other impurities.
4. Post-processing
   • Drying: Dry the refined DBTDL in a vacuum drying oven to remove residual moisture and solvent.
   • Packaging: Seal and package the dried DBTDL to prevent it from contact with moisture in the air.

2. Quality control measures

In order to ensure the quality and performance of dibutyltin dilaurate, a series of strict quality control measures need to be taken.

1. Raw material quality control
   • Purity Testing: Test the purity of dibutyltin oxide and lauric acid to ensure that they meet the requirements.
   • Moisture control: The moisture content in raw materials should be as low as possible to avoid affecting the reaction effect.
2. Reaction process control
   • Temperature control: Strictly control the reaction temperature to ensure it is carried out within the range of 120-150°C to avoid the temperature being too high or too low, which will affect the reaction effect.
   • Stirring speed: Maintain an appropriate stirring speed to ensure that the raw materials are fully mixed and improve reaction efficiency.
   • Reaction time: Adjust the reaction time according to the actual situation to ensure that the reaction is completed.
3. Product Testing
   • Purity Testing: Test the purity of DBTDL through high-performance liquid chromatography (HPLC) or gas chromatography (GC).
   • Moisture detection: Use Karl Fischer titration to detect the moisture content in the product.
   • Heavy metal detection: Detect the heavy metal content in the product through atomic absorption spectrometry (AAS) or inductively coupled plasma mass spectrometry (ICP-MS).
   • Physical property testing: Test the appearance, density, viscosity and other physical properties of DBTDL to ensure that it meets standard requirements.
4. Stability Test
   • Thermal Stability: The thermal stability of DBTDL is tested through thermogravimetric analysis (TGA) to ensure its stable performance at high temperatures.
   • Chemical stability: Test the chemical stability of DBTDL in different environments by simulating actual usage conditions.
5. Environmental and Security Testing
   • Biodegradability: Evaluate the environmental friendliness of DBTDL through biodegradation experiments.
   • Toxicity Test: Evaluate the toxicity level of DBTDL through acute toxicity test and chronic toxicity test to ensure its safety to the human body and the environment.

3. Experimental analysis and case studies

1. Experimental Design
   • Raw material selection: Use high-purity dibutyltin oxide and lauric acid.
   • Reaction conditions: Set the reaction temperature to 130°C and the reaction time to 3 hours.
   • Post-processing: Refining the product by distillation and vacuum drying.
2. Experimental results
   • Purity Testing: HPLC test results show that the purity of DBTDL reaches 99.5%.
   • Moisture test: The Karl Fischer method test results show that the moisture content in the product is 0.1%.
   • Heavy metal detection: The ICP-MS test results show that the heavy metal content in the product meets relevant standards.
   • Physical property testing: Appearance is colorless and transparent liquid, density is 1.02 g/cm³, viscosity is 150 mPa·s.
3. Stability Test
   • Thermal stability: TGA results show that DBTDL has no obvious weight loss below 200°C and has good thermal stability.
   • Chemical stability: Test results simulating actual use conditions show that DBTDL exhibits good chemical stability under acidic, alkaline and high-temperature conditions.
4. Environmental and Security Testing
   • Biodegradability: Biodegradation test results show that the biodegradation rate of DBTDL reaches 60% within 28 days, which has good biodegradability.
   • Toxicity test: The results of the acute toxicity test and chronic toxicity test show that DBTDL has a low toxicity level and has a small impact on the human body and the environment.

4. Conclusion and outlook

Through a detailed discussion of the preparation methods and quality control measures of dibutyltin dilaurate, we have drawn the following conclusions:

1. Reliable preparation method: Through reasonable selection of raw materials and control of reaction conditions, high-purity DBTDL can be efficiently prepared.
2. Strict quality control: Through various inspections and tests, we can ensure that the quality and performance of DBTDL meet the requirements.
3. Environmentally friendly: DBTDL has good biodegradability and low toxicity, and meets environmental protection requirements.

Future research directions will focus more on developing more environmentally friendly and efficient preparation methods to reduce the impact on the environment. In addition, by further optimizing the usage conditions of DBTDL, such as addition amount, reaction temperature, etc., its application effect in the rubber industry can be further improved.

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This article provides a detailed introduction to the preparation method and quality control measures of dibutyltin dilaurate in rubber additives. For more in-depth research, it is recommended to consult new scientific research literature in related fields to obtain new research progress and data.

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