“chemical engineering”

ĶOĶ 428

Professor Raimonds Valters

Course description: 3Credit units, 48 hours (32 lectures 16 practice)

Control forms: Exam
Course content:

• 
  Theoretical and practical application of the physical methods in organic chemistry. Classification of the physical methods. Spectroscopic methods and their classification.
  
• 
  Electronic Absorption Spectroscopy. Background of the theory of electronic spectra. Electron transitions and their classification. Molecular electronic levels of diatomic molecule. Morse function and Franck-Condon principle. Beer-Lambert rule. Solvent influence on the wavelength and the intensity of absorption bands. Solvatochromy. UV/VIS-spectrometers and their schematic design. Electronic spectra and structure of organic compounds. Olefins and polyenes. Arenes. Application of the UV/VIS spectroscopy in the quantitative determination of organic compounds and in the determination of chemical equilibrium constants.
  
• 
  Infrared Absorption Spectroscopy. Molecular vibrations and rotations. Basic principles and selection rules. IR spectrometers and their schematic design. Sample preparation and spectrum measurements in gaseous, liquid and solid phase and in solutions. Overview of the characteristic absorption of the chemical bonds. The influence of the molecular structure on the C=O group vibration band wavenumber and intensity (dependence on bond angle, electronic effects of the substituents, intramolecular dipole-dipole interaction, intramolecular hydrogen bonding). OH and NH bond absorption, intra- and intermolecular hydrogen bonding.
  
• 
  Nuclear Magnetic Resonance Spectroscopy. The resonance phenomenon (quantum mechanics model). Schematic design of NMR spectrometer, continuous wave and Fourier transform spectra. ¹H-NMR. Sample preparation and measurements of spectra. Information from NMR spectra: chemical shifts, spin-spin coupling constants, signal intensities. ¹H-chemical shifts. The influence of molecular structure on chemical shift: electronic effects of substituents, magnetic anisotropy of the neighboring groups, ring currents, intermolecular interactions - hydrogen bonding and solvent effects. Empirical correlations for predicting chemical shifts. Use of shift reagents. Spin-spin coupling. Classification of spin systems. First order and second order spectra. Interpretation of spin-spin coupling in first order spectra. Influence of the molecular structure on the ¹H,¹H coupling constants. Geminal, vicinal and long-range couplings. ¹³C,¹H coupling constants. Double resonance experiments (spin decoupling). Application of the nuclear Overhauser effect. Dynamic NMR spectroscopy. Exchange processes and measurements of their rate constants. Complete line shape analysis. ¹³C-NMR. Spin decoupling experiments: ¹H broad band decoupling, gated decoupling, ¹H off resonance decoupling.
  
• 
  ¹³C chemical shifts, effects of substiuents, g-effect. Empirical correlations for predicting chemical shifts: alkanes, alkenes, alkynes, arenes etc. ¹³C,¹³C coupling constants. Spin lattice relaxation of ¹³C nuclei. Pulse Fourier transform experiments, their advantages. Background of two-dimensional NMR experiments.
  
• 
  Mass spectrometry. The principle and the schematic design of mass spectrometer. Sample injection systems. Ionization methods. Fragmentation of organic compounds. The resolving power of mass spectrometer. Molecular ion and its relative stability. Isotopes and the elemental composition of molecular ions (M + 1, M + 2). Classification of the main fragmentation reactions of organic compounds. s-Bond cleavage, the rearrangements with hydrogen atom migration (McLafferty rearrangement), carbon skeletal rearrangements. Metastable ions. Fragmentation associated with main classes of organic compounds. Alkanes and cycloalkanes. Alkenes and cycloalkenes. Arenes. Alkanols, phenols. Ethers. Aldehydes and ketones. Carboxylic acids and their derivatives. Amines. Nitroderivatives. Haloalkanes. The characteristics of chloro and bromo containing doughtier ions. Aromatic heterocycles.
  
• 
  Problems. The determination of the molecular structure from the UV-VIS, infrared, ¹H and ¹³C- NMR, mass spectra and the molecular formula.
  

Literature:

1. 
   R.Valters. Applications of infra-red spectroscopy to the structure analysis of organic compounds (In Latvian). Riga Technical University, 1990, 81 p.
   
2. 
   R.Valters. Applications of nuclear magnetic resonance spectroscopy to organic chemistry (In Latvian). Riga Technical University, 1991, 110 p.
   
3. 
   R.Valters. Applications of electronic absorption spectroscopy to organic chemistry (In Latvian). Riga Technical University, 1992, 81 p.
   
4. 
   R.Valters. Applications of mass spectrometry to organic chemistry (In Latvian). Riga Technical University, 1993, 105 p.
   
5. 
   R.M.Silverstein, G.C.Bassler and Th.C.Morrill. Spectrometric identification of organic compounds. 3^rd ed. Wiley, New York, 1974 (Russian translation, 1977)
   
6. 
   H.Günther. NMR spectroscopy. An introduction. Wiley, Chichester, 1980 (Russian translation, 1984)
   
7. 
   M.Hesse, H.Meier and B.Zeeh. Spectroscopic methods in organic chemistry. G.Thieme Verlag, Stuttgart, 1997.
   
8. 
   D.W.Brown, A.J.Floid and M.Sainsbury. Organic spectroscopy. Wiley, Chichester, 1988.
   

Spectroscopic Data Tables:

1. 
   A.J.Gordon, R.A.Ford. The Chemist's companion (A Handbook of practical data, techniques and references). Wiley, New York, 1972 (Russian translation, 1976)
   
2. 
   E.Pretsch, Th.Clerc, J.Seibl, W.Simon. Spectral data for structure determination of organic compounds. 2^nd ed., Springer, London, 1989.
   

Problem Books:

1. 
   L.D.Field, S.Sternhell, J.R.Kalman. Organic Structures from Spectra. 2^nd ed., Wiley, Chichester, 1995.
   
2. 
   E.Pretsch, J.Seibl, A.Manz, and W.Simon. Aufgabensammlung zur Strukturaufklärung organischer Verbindungen mit spektroskopischen Methoden. Springer, Berlin, 1985.
   

Further Readings:

1. 
   H.Friebolin. Basic one- and two-dimensional NMR spectroscopy. 2^nd ed., VCH, Weinheim, 1993.
   

Organic chemistry for biomaterial technology.

ĶOĶ 429