How to Identify the IR of Methyl m-Nitrobenzoate

How to Identify the IR of Methyl m-Nitrobenzoate
••• Ryan McVay/Digital Vision/Getty Images

Infrared (IR) spectroscopy provides a rapid instrumental technique for identifying the major structural elements of organic (i.e., carbon-based) compounds. IR instruments measure the frequencies at which various bonds in a compound absorb radiation in the IR region of the electromagnetic spectrum. By convention, chemists state these frequencies in units of reciprocal centimeters (1/cm), or “wavenumbers.” The absorption frequencies of specific bonds tend to be distinctive. An O-H bond, for example, exhibits a broad absorption around 3400 1/cm. After obtaining the spectrum for a given compound, chemists use IR spectroscopy correlation tables to identify the types of bonds that occur in the compound. Methyl m-nitrobenzoate comprises a nitro group, or -NO2, and a methyl ester group, or C(=O)-O-CH3, attached to a benzene ring.

Step 1:

Identify the absorption peak of the C=O group of the ester by its strong absorption between 1735 and 1750 1/cm. This should be the strongest peak in the spectrum.

Step 2:

Locate the C-C(=O)-C stretch between 1160 and 1210 1/cm.

Step 3:

Identify the two -NO2 stretches in the ranges of 1490-1550 and 1315-1355 1/cm.

Step 4:

Locate the two C=C aromatic stretches at about 1600 and 1475 1/cm.

Step 5:

Identify the C-H stretch of the -CH3 group located between 2800 and 2950 1/cm. A -CH3 bend absorbance should also occur near 1375 1/cm.

Step 6:

Identify the C-H bends associated with the benzene ring. Locate the ortho C-H at 735 to 770 1/cm. Locate the meta C-H at 880 1/cm, and between 690 and 780 1/cm. The para C-H should be between 800 and 850 1/cm.

Related Articles

How to Read IR Spectrums
How Does IR Spectroscopy Work?
How to Calculate the Isoelectric Point of Peptides
How to Calculate HPLC Resolutions
How to Calculate the Coefficient of Molar Absorption
Chemical Properties of Benzoic Acid
Spectrometer Experiments
How to Calculate Alkalinity
What Is a Hydrocarbon Chain's Relationship to Fats...
What Is a Hydrocarbon Chain?
How to Identify Molecules as Polar or Non-Polar
Can We See Light Emitted by Hydrogen Atoms When They...
How to Calculate PH of Buffer Solutions
Types of Spectrometers
What Dissolves Oil?
How to Calculate the Calculations for Spectrophotometers
How to Calculate an Ionic Strength of a Buffer Solution
How to Calculate a Fraction Covalent
How to Calculate End Point

Dont Go!

We Have More Great Sciencing Articles!