FTIR spectroscopy

Introduction

Abstract:
Mineral oil is a liquid insulating material refined from petroleum. The main components of petroleum are alkanes, cycloalkanes and aromatic via, these components have excellent electrical properties and aging stability. According to the specific use of appropriate control of the content of each component, you can get transformer oil, switch oil and other insulation oil and a variety of lubricants. For example, aromatic hydrocarbons can effectively adsorb gases and can be used to make cable oils or capacitor oils, while naphthenic hydrocarbons can lower the freezing point of oils and can be used to make low-temperature lubricants.

According to DL/T 929-2005 "Infrared Spectroscopy for Determination of Structural Group Composition of Mineral Insulating Oil and Lubricating Oil”, infrared spectroscopy can be utilized to accurately and quickly determine the structural group composition of the oil in a qualitative and quantitative manner.
The infrared spectrometer can be used to accurately and quickly determine the structure group composition of the oil in a qualitative and quantitative way.

Key Words: Infrared Spectrometry, Mineral Insulating Oil, Lubricating Oil, Structure Group Composition

Click to view related products：FTIR-650 Fourier Transform Infrared Spectrometer

Principle
According to the mineral insulating oil, lubricating oil in the aromatic carbon in the infrared spectral region of 1610cm-1, chain alkanes in the 720cm-1 has a characteristic absorption, its absorbance into the empirical formula, so as to calculate the insulating oil, lubricating oil structure family composition in the

The content of aromatic carbon (CA %), alkane chain carbon (CP %) and cycloalkane (CN %) in the structural group composition of insulating oil and lubricating oil is calculated by substituting their absorbance into the empirical formula.

Experimental conditions
Instrument and accessories;
FTIR-650 Fourier Transform Infrared Spectrometer
Hydroxyl test accessories Hydroxyl test stand

Test conditions
Resolution: 4cm-1
Number of scans: 32
Detector: DTGS

Others
Carbon tetrachloride (CCl4 ): Analytically pure (A.R)

Liquid cell optical range length determination:
Using the interference fringe method, the empty fixed liquid pool in the optical path scanning (scanning range of 1900cm-1 - 600cm-1 ) to get the interference fringe containing the great and small values, according to the formula:

Sample Determination
1. Use a glass syringe to inject the oil sample carefully into the liquid cell (note that there should be no size bubbles in the liquid cell, otherwise re-inject the sample), place the liquid cell in the optical path and scan:
2. Make a baseline of the scanned spectrum as follows and record the absorbance of the sample at 1610m-1 and 720cm-1.

3. Substituting the absorbance obtained in 2 into the empirical formula gives the aromatic carbon (CA %), alkyl chain carbon (CP %) and cycloalkane (CN %) content.
4. The following table lists the test results of several samples for aromatic carbon content: Aromatic Carbon Content (CA %)

	Aromatic Carbon Content (CA %)
	1	1	1	1
1	5.59	5.59	5.58	5.586
2	5.66	5.66	5.67	5.633
3	5.49	5.48	5.49	5.486
4	5.45	5.46	5.45	5.453

Conclusion
Using infrared spectroscopy to determine the structure group composition of mineral insulating oil and lubricating oil, combined with the empirical formula in DL/T 929-2005, it is convenient, fast and accurate to determine the structure group composition of mineral insulating oil and lubricating oil.
oils can be easily, quickly and accurately determined by combining with the empirical formula in DL/T 929-2005.