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WGU-Organic Chem 13
Organic Chemistry Laboratory Techniques
Question | Answer |
---|---|
IR | The infrared spectrum of a sample is recorded by passing a beam of infrared light through the sample. Examination of the transmitted light reveals how much energy was absorbed at each wavelength |
NMR | In a magnetic field, NMR active nuclei (such as 1H or 13C) absorb at a frequency characteristic of the isotope. The resonant frequency, energy of the absorption and the intensity of the signal are proportional to the strength of the magnetic field |
Distillation | method of separating mixtures based on differences in their volatilities in a boiling liquid mixture |
IR absorption O-H | 3200-3500 strong and broad |
IR absorption N-H | 3100-3500 medium |
IR absorption C-H | 2850-3100 medium to strong |
IR absorption C triple bond H | 2100-2260 weak |
IR absorption C=O | 1630-1800 strong |
IR absorption C=C | 1600-1680 weak |
IR absorption C-O | 1050-1250 strong |
IR absorption alkane C-H stretching | 2850-3000 strong |
IR absorption alkane CH2 bending | 1450 medium |
IR absorption alkane CH3 bending | 1375 and 1450 weak to medium |
IR absorption alkene C-H stretching | 3000-3100 weak to medium |
IR absorption alkene C=C stretching | 1600-1680 weak to medium |
IR absorption alkyne C-H stretching | 3300 weak to medium |
IR absorption alkyne C triple bond C stretching | 2100-2260 weak to medium |
IR absorption alcohol O-H(hydrogen bonded) | 3200-3500 medium, broad |
IR absorption alcohol C-O | 1050-1250 medium |
IR absorptions of aromatic hydrocarbons | C-H stretching 3000 medium to weakC-H bending 690-900 strongC=C stretching 1475 and 1600 strong to medium |
IR absorptions of carboxylic acids C=O | 1700-1725 |
IR absorptions of esters C=O | 1735-1800 |
IR absorptions of amides C=O | 1630-1680 |
signal splitting n+1 rule | a proton with n neighbors appears as a cluster of this rules peaks. |
Carbon chemical shift 0-50 | sp3 carbon(tertiary>secondary>primary) |
carbon chemical shift 50-80 | sp3 carbon bonded to electronegative element such as N, O, X. the more electronegative the element,the larger the chemical shift. |
Carbon chemical shift 100-160 | sp2 carbon of an alkene or an aromatic compound |
carbon chemical shift 160-180 | carbonyl carbon of a carboxylic acid or carboxylic acid derivative |
carbon chemical shift 180-210 | carbonyl carbon of a ketone or an aldehyde |
goal of distillation | separating mixtures based on differences in their volatilities in a boiling liquid mixture |
how distillation works | Water is distilled to remove impurities, such as salt from seawater. Air is distilled to separate its components—notably oxygen, nitrogen, and argon—for industrial use |
fractional distillation | the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate |
simple distillation | simple distillation is usually used only to separate liquids whose boiling points differ greatly (rule of thumb is 25 °C)or to separate liquids from involatile solids or oils |