E13 – Infrared Spectral Interpretation

Infrared Spectral Interpretation

One-Day Course E13-30, Wednesday, November 20th, 8:30am – 5:00pm

 Dr. Brian C. Smith, Spectros Associates, Shrewsbury, MA

This is a one-day introduction to infrared spectral interpretation. You will learn how to integrate the peak position, height, and width information in a spectrum to successfully determine unknown molecular structures and to perform identities properly. The five ways of attacking mixture spectra are discussed, then a 12-step program to interpret spectra is presented. The diagnostic infrared bands of many economically important molecules including hydrocarbons, alcohols, ketones, esters, and polymers are presented. Attendees practice interpreting many unknown spectra in class with the instructor’s guidance.

This course will benefit anyone who analyzes samples to determine chemical structures, and everyone for whom measuring infrared spectra is part of their job. Beginners will benefit from the introductory nature of this course. Experienced interpreters will benefit by learning systematic approaches to interpreting spectra and the review of spectra of important functional groups.

1. The Fundamentals of Infrared Interpretation
     * The properties of light
     * Molecular vibrations
     * The meaning of peak positions, heights, and widths
     * A strategic approach to spectral interpretation
        – Dealing with mixtures
        – Performing identities properly
        – A systematic 12-Step approach to infrared interpretation
2. Functional Group Analysis of Hydrocarbons
     * Alkanes: C-H stretching and bending vibrations
        – Straight chain alkanes
        – Estimating hydrocarbon chain length from IR spectra
     * Aromatic hydrocarbons
        – Mono-substituted benzene rings
        – Distinguishing ortho, meta, and para isomers
3. Alcohols and Phenols
     * Differentiating primary, secondary, and tertiary alcohols
     * Phenols
     * Distinguishing alcohols from water
4. The Carbonyl (C=O) Functional Group
     * Introduction to carbonyl spectra
     * Ketones
     * Esters: the rule of 3
     * Summary
5. Introduction to the Infrared Spectra of Polymers
     * Low- and high-density polyethylene
     * Polypropylene
     * Polystyrene
     * Polyethylene Terephthalate (PET)

Dr. Brian C. Smith is founder and principal of Spectros Associates. He has been a spectroscopist for over 30 years and was employed by Bell Labs and Digilab. He is an experienced trainer; thousands of people have benefited from his instruction as part of Spectros Associates since 1992. Dr. Smith is the author of three popular books on spectroscopy; Fundamentals of FTIR and Infrared Spectral Interpretation published by CRC Press, and Quantitative Spectroscopy: Theory and Practice published by Academic Press. Dr. Smith earned his Ph.D. in Chemistry from Dartmouth College and graduated with highest honors from Rochester Institute of Technology with a B.S. in Chemistry.