What functional groups correspond to the characteristic peaks of the infrared spectrum of methyl methacrylate?

Title: Infrared spectral characteristic peaks of methyl methacrylate: resolution of its functional groups

guide segment: Methyl methacrylate is an important acrylate compound, which contains a variety of functional groups in its structure. In infrared spectroscopy (IR) analysis, these functional groups will show specific characteristic peaks. This article will analyze these characteristic peaks and their corresponding functional groups in detail to help you better understand the structure of the substance.

1. Stretch Vibration of Carbon-Oxygen Double Bond (C = O) characteristic peak: about 1720-1750cm ^-1 Analysis: The ester group (COO) in methyl methacrylate will show a strong C = O stretching vibration peak in IR spectrum, usually located at 1720-1750cm -1. The peak in this region is due to the symmetrical stretching vibration of the carbon-oxygen double bond in the ester group. The position of the peak may vary slightly due to the electrical effects of neighboring groups, but it is usually around 1730cm ^-1.

2. Stretch Vibration of Carbon-Oxygen Single Bond (C-O) characteristic peak: about 1250-1300cm ^-1 Analysis: C- O single bond absorption peaks in esters usually appear at 1250-1300cm ^-1. In methyl methacrylate, the C- O bond in the methoxy group (OCH3) will show this characteristic peak. The absorption peak in this region is usually a medium-strong peak, which complements the stretching vibration of C = O and confirms the existence of ester groups.

3. Stretch Vibration of Carbon-Carbon Double Bond (C = C) characteristic peak: about 1600-1680cm ^-1 Analysis: Due to the unsaturated acrylate group in the structure of methyl methacrylate, its double bond (C = C) will show two asymmetric stretching vibration peaks, which are located at about 1635cm ^-1(ν1) and 1610cm ^-1(ν3) respectively. These peaks indicate the presence of a conjugated double bond system in the molecule, further validating its structure.

4. C- O-C symmetric stretching vibration in ester groups characteristic peak: about 1050-1150cm ^-1 Analysis: The C- O-C symmetrical stretching vibration in the ester group usually occurs between 1050-1150cm ^-1. The moderate intensity absorption peak in this region, coupled with the characteristic peak of the C- O single bond, can effectively confirm the presence of the ester group, especially in the relative position of the C = O and C- O-C peaks.

5. Bending vibration of a carbon-hydrogen bond (C-H) characteristic peak: about 600-900cm ^-1 Analysis: In methyl methacrylate, the C- H flexural vibration of methyl (CH3) and methoxy (OCH3) occurs at about 800cm ^-1 and 700cm ^-1, respectively. These peaks often show different shapes and positions that help distinguish different types of C- H bonds.

Conclusion: By analyzing the infrared spectrum of methyl methacrylate, the characteristic peaks of C = O, C- O, C = C, C- O-C and C- H groups can be clearly identified. The presence of these peaks not only helps to confirm the structure of the substance, but also verifies its properties as an acrylate. As a structural analysis tool, infrared spectroscopy is of great significance for the identification of functional groups in materials such as light stabilizers, coatings, adhesives, etc.