sample_FTIR_report - They DOUBLED SPACED the report so I...

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Unformatted text preview: They DOUBLED SPACED the report so I could add comments between the lines clearly stated the unknown # Conclusion Unknown number O-69 was an ester and was correctly identified as ethyl butyrate. O showed they were capable of using ISIS draw to draw and import an image of a chemical structure O The sample was prepared neat between salt plates and gave a distinguishable FTIR spectral reading. The presence of a strong sharp stretch for the carbonyl C=O at listed absorbancies that clearly nailed the functional group 1717.3cm– and C—O at 1170.7 cm– and absorbencies were determined. The absence of O-H/N-H, and aromatic undertone absorbencies associated with alcohols, amines and listed the most important aromatics the eliminated these as possibilities and functional groups were no longer absorbancies in the body of the report. considered. The absence of double and triple bonding absorbencies (excluding the NOTE, these are their measured values obvious carbonyl) left only the ethers, esters, ketones and aldehydes as possibilities. The determining factor in the identification of unknown O-69 as an ester was the presence of a strong sharp stretch for the C-O at 1170.7 cm– in the C–O region between 1100-1300 cm–. This characteristic coupled the carbonyl stretch left only the ester and eliminated ether and aldehyde functional groups as possible matches. The fingerprint region of the original sample was carefully examined and matched alongside to the actual spectrum for said how possibilities were eliminated ethyl butyrate referenced on the NIST web site1 which confirmed unknown O-69 as ethyl butyrate. discussed how their spectrum matched to that of actual provided appropriate references Ref: 1. MISSING — perhaps the student could have added a list of the names and structures of other possible esters that were good candidates from the list of possibilities given in class. ADD a Cover Sheet gave their observed measured values Correlation Table Specific Functional Group carbonyl C=O alkene CH2 alkane CH3 saturated C-C ester C-O Observed Frequency Vibration (cm-1) 1717.3 1468.1 1371.6 1300.0 1170.7 Intensity strong moderate strong medium strong Shape peak sharp peak sharp sharp clearly stated how the sample was prepared Experimental FT-IR Spectrum - Ethyl Butyrate, Sample Ran Neat Although their spectrum gave a poor PDF file appearance, it was included. Actual FT-IR Spectrum * - Ethyl Butyrate, Neat O O * Source: correctly scaled the actual and measured spectra so the 1000 and 2000 cm regions matched for easy comparison ...
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This note was uploaded on 09/09/2011 for the course CHEM 231l taught by Professor Gergens during the Spring '11 term at Mesa CC.

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