Cyclohexanone
CyclohexanoneOXIDATION OF CYCLOHEXANOL
TO CYCLOHEXANONE
The oxidation of cyclohexanol to cyclohexanone involves the
removal of hydrogen from the OH group. After separation and
purification, an Infrared Spectrum will be run to determine the
composition of the recovered material.
Infrared Spectroscopy is a very powerful technique used in the
determination of molecular structure and the identification of
unknown organic materials. The infrared spectrum yields direct
information about the presence or absence of key functional groups.
�The region of the infrared spectrum which is of greatest interest to
organic chemists is the wavelength range 2.5 to 15 micrometers
which correspond to approximately 4000 to 600cm-1�(Young). �When
atoms or molecules absorb light, the incoming energy excites a
quantized structure to a higher energy level. The type of excitation
depends on the wavelength of the light. Electrons are promoted to
higher orbirtals by ultraviolet or visible light, vibrations are excited by
infrared light, and rotations are excited by microwaves� (Tissue).
IR spectroscopy is the measurement of the wavelength and
intensity of the absorption of infrared light by a sample. The
wavelength of IR absorption bands are characteristic of specific types
of chemical bonds.
An IR spectrophotometer is an instrument which is designed to
obtain an infrared spectra of a molecule. An IR spectra is obtained by
first irradiating a sample with an IR source of light. The light passes
through the sample, which can be in solution or contained within a
salt plate, and then onto an IR light detector. The spectrum is
analyzed by examining at which frequency the peaks occur. Different
peak frequencies indicate different types of vibrational motion and
hence, different types of chemical bonds. The peak intensities are
usually noted as percent transmittance which compares the amount of
light absorbed compared to the amount of IR light that was not
absorbed. The frequencies are normally listed in wave numbers (in
units of reciprocal centimeters).
Experiment
The oxidation of cyclohexanol by dichromate occurred in the
presence of sulfuric acid which yielded cyclohexanone according to the
balanced redox reaction below:
3 + Cr2O7-2 + 8H+ -- 3 + 2Cr+3 + 7H2O
In the presence of excess dichromate, cyclohexanol oxidizes to adipic
acid. To maximize yield, the following reaction was prevented:
3 + 4Cr2O7-2 + 32H+ -- 3HOOC(CH2)4COOH + 8Cr+3 + 19H2O
The addition of methanol reduced the excess dichromate according to
the balanced redox reaction below:
CH3OH + Cr2O7-2 + 8H+...
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