I. Preface

To obtain engine oil with better performance, humans have synthesized various types of engine oil through chemical methods. This is known as chemically synthesized engine oil, or simply synthetic engine oil. Synthetic engine oil is a type of artificially manufactured engine oil. During its production process, various natural substances are selected for chemical decomposition, and then combined with other substances to form synthetic engine oil. During the production and synthesis process of synthetic oil, it is very likely that a trace amount of water will dissolve in it. Although the amount is very small, it will still affect the original performance and quality of the oil. Therefore, the detection of water content is also necessary.

This method adopts Carl. The Fischer moisture meter (volumetric method) is used to measure the moisture content in it. It has good repeatability and can accurately measure the weak moisture content.

Ii. Instruments and Reagents

2.1 Instruments

JH-V3 Karl Fischer moisture titrator (volumetric method), syringe, analytical balance, etc

2.2 Reagents

Karl Fischer titrant, chloroform, n-propanol.

Iii. Experimental Methods

3.1 Sample Testing

Through the liquid discharge device of the moisture titrator, the residual liquid is removed and chloroform - n-propanol (2 3) Put 50mL of solvent into the titration cup. The solvent should cover the electrode. After setting the parameters, the instrument starts the pre-titration. When the instrument is in standby mode, click on the system injection, open the rubber stopper of the feeding port, add the sample containing an appropriate amount of water to the titration cup, immediately cover the rubber stopper, click on Start measurement, and use Karl. Titrate the Fischer titrant to the endpoint, input the sample weight, and calculate the moisture content of the sample.

The parameters of the titrator are set as shown in Table 1:

Table 1 Titration Parameter Settings

Results and Discussion

4.1 Experimental Results

The experimental results are as shown in Table 2:

Table 2 Test Results

4.2. Conclusion

The moisture content of the synthetic oil detected this time was very low, so the sampling volume was increased. However, considering the dissolution issue, n-propanol-chloroform was used as the solvent. The measured data had good repeatability and could meet the detection requirements.

References

Ren Lingyun, Hu Xuechun, Li Zhenhua, et al. Determination of Moisture Content in Animal and Vegetable Oils and Fats - Karl Fischer Method [C]