Spectra, Aldrich Library

The Aldrich Library of Infrared Spectra , 3rd ed., Aldrich chemical Company, Milwaukee, WI, 1981, by Pouchert contains more than 12,000 IR spectra so arranged that the user can readily see the change that takes place in a given spectrum when a slight change is made in the structure of a molecule. The same company also publishes the Aldrich Library of FT-IR Spectra and the Aldrich Library of NMR Spectra , both also by Pouchert. A similar volume, which has ir and Raman spectra of about 1000 compounds, is Raman/Infrared Atlas of Organic Compounds , 2nd ed., VCH, New York, 1989, by Schrader. 

FT-IR 1(2) 186A. The Fourier-Transform Infra-Red spectrum of benzoic acid is in Edition 1, Volume 2, page 186A of The Aldrich Library of FT-IR Spectra. 

Aldrich Library of FTIR Spectra (1985), 3 Vols. Milwaukee, WI Includes vapor-phase spectrum Vol. 3... 

Nuclear Magnetic Resonance (NMR) Spectroscopy is by far the most widely used analytical technique in the modern organic chemistry lab. Numerous monographs have been written on this subject. It would be impossible to cover all of the significant points here. The reader who is interested in knowing what the proton ( H) or carbon (13C) spectrum of a particular compound is directed to the Aldrich Library of NMR Spectra or the Sadtler Library. 

Fig. 2.6. NMR spectrum of l-phenyl-2-butanol showing tiie diastereotopic nature of C(l) protons. Reproduced from Aldrich Library of C and NMR Spectra, Vol. 2, 1993, p. 386.

FtGURE 19-44 Proton NMF spectrum. (From C. J. Poucherl, The Aldrich Library of NMR Spectra, 2nd ed.. Milwaukee, Wl The Aldrich Chemical Company. With permission.)... 

Pouchert, C. J. The Aldrich Library of Infrared Spectra, 3d ed. Aldrich Chemical Company, Milwaukee, 1981, p. 1,592, spectrum A. 

Infrared spectrum reference to the Aldrich Library of FT-IR spectra NMR spectrum reference to the Aldrich Library of and FT-NMR spectra Literature references to the primary literature on the uses of the compound Toxicity... 

Weigh the yellow needles of usnic acid and calculate the percentage of the acid extracted from the dry lichen. Determine the melting point (use the evacuated melting point technique) and compare your value to that found in the literature. Using a solvent system of ethyl acetaterhexane (1 4) and a UV lamp for visualization, compare the crude extract with the purified usnic add byTLC (Revalue for usnic acid is 0.32). Obtain an IR spectrum and compare it with that of an authentic sample or one from the literature (The Aldrich Library of IR Spectra and/or SciFinder Scholar). 

Record the infrared spectrum and compare it to that reported in the literature Aldrich Library of Infrared Spectra and/or SciFinder Scholar). 

Record the weight of product and calculate the percent yield. Determine the boiling point and refractive index (optional) of your material and compare your results with those reported in the literature for octane. Obtain an IR spectrum. Compare your results with those reported in the literature Aldrich Library ofIR Spectra and/or SciFinder Scholar). Also, compare your IR spectrum to that of the 1-octene starting material. Can you establish from the above data if your sample is contaminated by traces of the pentane extraction solvent If not, how would you go about determining the presence of this potential impurity ... 

Obtain an IR spectrum of the alcohol and compare your result to that recorded in the literature (Aldrich Library of IR Spectra and/or SciFinder Scholar). 

Obtain an IR spectrum of each material and compare the results with an authentic sample or spectra found in the literature The Aldrich Library ofIR Spectra and/or SdFinder Scholar). Interpretation of the spectra allows an unambiguous determination of substitution based on the presence or absence of absorption in the 1100- to 900-wavenumber region of the spectrum. 

Weigh the dried product and calculate the percent yield. Deterrnine the melting point and compare it with that listed in the Reagent and Product table. Obtain an IR spectrum and compare your result to that of an authentic sample, or to one in the literature The Aldrich Library oflR Spectra and/or SdFinder Scholar)... 

Purification and Characterization. Weigh the air-dried sucdnirnide and calculate the percent yield. Determine the melting point and compare your value to that in the literature. Obtain an IR spectrum and compare your spectrum with that shown in the literature (The Aldrich Library ofIR Spectra and/or SciFinder Scholar). 

Obtain the IR spectrum of your product and compare it with one in the literature (The Aldrich Library of IR Spectra and/or SdFinder Scholar). 

Purification and Characterization. No further purification of the product is usually necessary. Note the hyacinth-like odor of the liquid. Determine the refractive index and compare it to the literature value (lit. value = 1.6070 at 20 °C, 78% trans isomer). Obtain IR and NMR spectra of the oil. In the infrared, the cis isomer shows a phenyl C—H bend at 770 cm , while the trans isomer shows this bending mode at 731 and the alkene C—H out-of-plane mode is found at 941 cm (see Bibliography, Strom et al.). Compare your results with the spectrum recorded in the literature The Aldrich Library ofIR Spectra and/or SciFinder Scholar). 

Obtain an IR spectrum and NMR spectra of the sample and compare your results with those in the literature The Aldrich Library of IR Spectra, The Aldrich Library of NMR Spectra, and/or the corresponding spectral data available online (e.g., SdFinder Scholar)). 

Figure 24.5 The High-Resolution Proton NMR Spectrum of 2-Propanol Dissolved in Deuterated Chloroform. From Charles J. Pouchert and John R. Campbell, The Aldrich Library of NMR Spectra, The A dr ch Chemical Co., 1974, Vol. I, p. 85.

Figure 24.6 The Proton NMR Spectrum of Ethanol, (a) With a trace of water present. Because of exchange of the hydroxyl proton with water protons, the hydroxyl proton shows no spin-spin splitting. From G. W. Castellan, Physical Chemistry, 3rd ed., Addison-Wesley, Reading, MA, 1983, p. 606. (b) Highly purified ethanol. In the absence of water, the spin-spin splitting of the line from the hydroxyl proton is split into three lines by the methylene protons. From I. N. Levine, Molecular Spectroscopy, Wiley, New York, 1975, p. 353. (c) In deuterated chloroform. In this spectrum, the solvent interaction with chloroform moves the hydroxyl line to near 2.6 ppm. The splitting into three lines is not quite resolved. From C. J. Pouchert and J. R. Campbell, The Aldrich Library of NMR Spectra, The Aldrich Chemical Co., 1974, Vol. I, p. 79.

The infrared absorption spectrum of aspartame is also recorded in the Aldrich IR Library [47], and by Grant and coworkers [8,23]. 

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