Dimethylformamide (DMF) is a widely used organic solvent and reagent in various industrial and laboratory applications. It has a high boiling point, low volatility, and good solvating power for a range of organic and inorganic compounds. One of the methods to characterize DMF and its purity is by infrared (IR) spectroscopy, which measures the absorption of infrared radiation by the molecular vibrations of DMF.
In this article, we will briefly introduce the IR spectrum of DMF and its main features. We will also discuss some of the factors that can affect the IR spectrum of DMF, such as temperature, concentration, and impurities.
The IR Spectrum of DMF
The IR spectrum of DMF is shown in the figure below. The spectrum is divided into two regions: the functional group region (4000-1500 cm-1) and the fingerprint region (1500-400 cm-1). The functional group region contains the characteristic peaks of the functional groups present in DMF, such as the carbonyl group (C=O), the amide group (N-H), and the methyl group (C-H). The fingerprint region contains the peaks that are unique to the molecular structure of DMF, such as the bending vibrations of the C-N-C and C-O-C bonds.
Some of the prominent peaks in the IR spectrum of DMF are:
- The peak at 1670 cm-1 corresponds to the stretching vibration of the carbonyl group (C=O). This peak is strong and sharp, and it is one of the most distinctive features of DMF.
- The peak at 3400 cm-1 corresponds to the stretching vibration of the amide group (N-H). This peak is broad and weak, and it may overlap with the peak of water (O-H) if present in the sample.
- The peaks at 2960 cm-1 and 2870 cm-1 correspond to the asymmetric and symmetric stretching vibrations of the methyl group (C-H), respectively. These peaks are medium and sharp, and they indicate the presence of aliphatic hydrogens in DMF.
- The peak at 1530 cm-1 corresponds to the bending vibration of the amide group (N-H). This peak is medium and sharp, and it is another characteristic feature of DMF.
- The peak at 960 cm-1 corresponds to the bending vibration of the C-N-C bond. This peak is weak and sharp, and it reflects the geometry of the DMF molecule.
- The peak at 670 cm-1 corresponds to the bending vibration of the C-O-C bond. This peak is weak and sharp, and it is also related to the molecular structure of DMF.
Factors Affecting the IR Spectrum of DMF
The IR spectrum of DMF can be influenced by several factors, such as temperature, concentration, and impurities. Some examples are:
- Temperature: As the temperature increases, the molecular vibrations become more energetic and intense, resulting in higher absorption peaks. However, if the temperature is too high, some bonds may break or rearrange, causing changes in the IR spectrum.
- Concentration: As the concentration of DMF increases, the number of molecules absorbing infrared radiation also increases, resulting in higher absorption peaks. However, if the concentration is too high, some intermolecular interactions may occur, such as hydrogen bonding or dipole-dipole interactions, causing shifts or broadening in the IR spectrum.
- Impurities: If there are impurities present in the DMF sample, such as water, alcohols, acids, or bases, they may introduce new peaks or alter existing peaks in the IR spectrum. For example, water can form hydrogen bonds with DMF, causing a shift in the N-H peak from 3400 cm-1 to 3300 cm-1. Impurities can also affect the purity and quality of DMF, which may have implications for its applications.
Conclusion
In this article, we have briefly overviewed the IR spectrum of DMF and its main features. We have also discussed some of the factors that can affect the IR spectrum of DMF, such as temperature, concentration, and impurities. IR spectroscopy is a useful technique to characterize DMF and its purity, as well as to monitor its reactions and transformations.
How to Buy dimethylformamide?
If you are looking for a reliable dimethylformamide supplier in China, you can visit our SHANDONG QIBO NEW ENERGY CO., LTD. website www.qiboch.com. We have various grades and quantities of dimethylformamide(cas68-12-2) available for sale. We also sell other industrial chemicals such as acetonitrile, Methylene Chloride, glacial acetic acid, ethanol, etc. We ship our products worldwide at competitive prices. Contact us today for a free quote.
