Organic 2 Lab Report Essay Example
Exp.11) Identification of unknown ketones.
Introduction:
Given five samples of a known ketone derivative, the purpose of this experiment is to identify which unknown ketone derivative corresponds to the five known samples. In other words, using specific methods of compound detection, it is possible to match an unknown compound with a known compound because similar compounds will display similar characteristics. In this experiment, identification of the unknown ketone is accomplished through thin layer chromatography, melting point, and 1H-NMR spectroscopy. The unknown ketone is from a homologous series of methyl ketones.
CH3CO (CH2) nCH3
The first step in the lab is the preparation of the solvent used in the developing chamber for thin layer chromatography. The solvent used is a 3:1 mixture of toluene and petroleum. After the developing chamber is prepared, it is essential to begin preparation of the unknown DNPH derivative[6]. The preparation of the 1,2 DNPH derivative of a ketone is in fact a small organic synthesis which produces a fraction of a gram of product.
The second part of the lab makes use of NMR Spectrometry. NMR takes advantage of the magnetic properties of the 1H & 13C nuclei. We are only concerned with 13C because 12C does not have a magnetic spin and will go undetected in the NMR spectrum. Atoms with spin act like bar magnets and when placed in a large magnetic field the atoms tend to align with the field. There are two fundamental ways of obtaining an NMR spectrum; continuous-wave (CW) where a sample (unknown) is constantly irradiated with RF waves while the magnetic or RF frequency is varied, this induces a change in nuclei spin and these changes are measured and converted into peaks on a chart, Fourier-transform NMR (FT-NMR) spectrometer, is where the sample is irradiated with a short intense pulses of full-spectrum RF radiation; this action displaces the nuclei from its equilibrium division. This displacement response is recorded;
Introduction:
Given five samples of a known ketone derivative, the purpose of this experiment is to identify which unknown ketone derivative corresponds to the five known samples. In other words, using specific methods of compound detection, it is possible to match an unknown compound with a known compound because similar compounds will display similar characteristics. In this experiment, identification of the unknown ketone is accomplished through thin layer chromatography, melting point, and 1H-NMR spectroscopy. The unknown ketone is from a homologous series of methyl ketones.
CH3CO (CH2) nCH3
The first step in the lab is the preparation of the solvent used in the developing chamber for thin layer chromatography. The solvent used is a 3:1 mixture of toluene and petroleum. After the developing chamber is prepared, it is essential to begin preparation of the unknown DNPH derivative[6]. The preparation of the 1,2 DNPH derivative of a ketone is in fact a small organic synthesis which produces a fraction of a gram of product.
The second part of the lab makes use of NMR Spectrometry. NMR takes advantage of the magnetic properties of the 1H & 13C nuclei. We are only concerned with 13C because 12C does not have a magnetic spin and will go undetected in the NMR spectrum. Atoms with spin act like bar magnets and when placed in a large magnetic field the atoms tend to align with the field. There are two fundamental ways of obtaining an NMR spectrum; continuous-wave (CW) where a sample (unknown) is constantly irradiated with RF waves while the magnetic or RF frequency is varied, this induces a change in nuclei spin and these changes are measured and converted into peaks on a chart, Fourier-transform NMR (FT-NMR) spectrometer, is where the sample is irradiated with a short intense pulses of full-spectrum RF radiation; this action displaces the nuclei from its equilibrium division. This displacement response is recorded;