TY  - BOOK
AU  - Simeen Sattar
TI  - Quinacridone Red and Violet: An Infrared Surprise:  (Journal Article)
T2  - American Chemical Society, Volume 100, Issue 8
SN  - 0021-9584
U1  - 540.7 
PY  - 2023///
CY  - USA
PB  - :American Chemical Society
KW  - Nonmajor Courses
KW  - Laboratory Instruction
KW  - Hands-On Learning/Manipulatives
KW  - Applications of Chemistry
KW  - Dyes/Pigments UV−Vis
KW  - Spectroscopy IR Spectroscopy
N1  - ***______{For Hard Copy, Please visit Library.}________***
N2  - Abstract
 
Quinacridone red and violet are visually different colors, an observation confirmed by their visible reflectance spectra and CIE L*a*b* coordinates. However, their IR spectra are extremely similar. Though chemically identical, the two quinacridones are polymorphs. In this experiment, designed for and tested by nonscience majors, the pigments are extracted from oil paints with hexane in a short procedure involving sonification and centrifugation. ATR-FTIR spectra of the recovered brilliantly colored powders reveal the presence of a calcium carbonate filler in one of the two paints. Factoring out the carbonate bands, the spectra are nearly identical. Students must reconcile the evidence of color and the evidence of the spectra.


UR  -  https://pubs.acs.org/doi/epdf/10.1021/acs.jchemed.3c00316
ER  -