In this experiment, porphyrin is synthesized through non-solvent reaction conditions using benzaldehyde and pyrrole as starting materials. Porphyrins are molecules that play essential roles in the biological systems. Iron-containing porphyrins called hemes are important in the oxygen-carrying activity of hemoglobin. Other systems in which porphyrin plays an important role include the electron transport chain reactions and photosynthesis reactions. Preparation of porphyrin is started by building its carbon framework- porphyrinogen.
Porphyrinogen is built by a total of 8, series of substitution reactions between pyrrole and benzaldehyde. After the framework has been established, porphyrinogen is then oxidized to yield the desired product-porphyrin. Porphyrin is a fully conjugated aromatic compound with18 electrons. Figure 1: Synthesis of mesotetraphenylporphyrin via high temperature reaction conditions Figure 2: Porphyrin assembly from eight electrophilic aromatic substitution reactions Determination on the purity of the obtained compound was done through both spectral and chromatographical analyses.
Chromatographic techniques done for the purification of porphyrin include Thin Layer Chromatography (TLC) and Column Chromatography. Spectral analysis was done through the use of UV-Visible Spectroscopy. This experiment aims to synthesize 5, 1, 15, 20 -Tetraphenylporphyrin via solvent-less gas phase reaction and analysis through TLC, column chromatography and visible spectral analysis. Procedure: This experiment was carried out by capping a 5 ml conical vial with a septum bearing screw cap. The vial was then placed in a heating mantle filled with sand, where 1.
The Essay on Analysis of Chromatography Methods
Chromatography is the method of separating chemical substances that makes uses of the relative rates at which they are adsorbed from a moving stream of gas or liquid on a stationary substance, which is usually a finely divided solid, a sheet of filter material, or a thin film of a liquid on the surface of a solid. It is a versatile method that can separate very complex mixtures even in the absence ...
5 inches of the vial was submerged in the sand. Heat was then applied to the sand bath, and when the temperature of the bath reached 170°C, a 2 micro liter syringe was used to inject 10 micro liter of benzaldehyde through the septum. When the temperature reached to 180°C, a 10 micro liter syringe was used to inject 7 micro liters of pyrrole through the septum. Then the temperature of the sand was raised to 250°C. The vial was heated at 250°C for 15 min, and was left to cool down at room temperature afterwards.
After the vial was cooled down a 1- ml of CH2Cl2 was used to rinse the cap liner and walls of the vial. Figure 3: Schematic diagram of gas phase reaction synthesis of TPP Thin layer Chromatography (TLC) Thin-layer chromatography (TLC) was used as a technique for identifying compounds, determining their purity and following the progress of a reaction. It also permits the optimization of the solvent system for a given separation problem. As stationary phase, a special finely ground matrix silica gel was coated on a glass plate, a metal or a plastic film as a thin layer (~0.
25 mm).
In addition, a binder like gypsum was mixed into the stationary phase to make it stick better to the slide. A 7 : 1 mixture of hexane/ ethyl acetate was prepared. A small amount of solvent was placed in the container. The lower edge of the plate was then dipped in a solvent. The solvent travels up the matrix by capillarity, moving the components of the samples at various rates because of their different degrees of interaction with the matrix and solubility in the developing solvent. The solvent was then left to travel up the plate until ~1 cm from the top.
The Essay on Silica Gel Hexane Results Lipids
I. Introduction In this experiment, lipids from ground nutmeg are extracted using a combination of solvents and identify the lipids through chromatography. The purpose of using solvent combinations is to elute the lipids based on their polarity to binding of the silica gel. The chromatography is performed on a silica gel plate and the use of iodine to visualize the lipids. By calculating the Rf ...
The solvent was marked accordingly. A ruler was then used to observe the travel points of the leading spot and the impurities on the silica plate. Tetraphenylporphyrin spots which were violet in color and other notable marks were noted. The Rf values were computed for each accordingly. Purification- Column chromatography A silica gel column was prepared fitted with a Teflon stopcock. A 5-ml mixture of 7:1 hexane:ethyl acetate was added to it. Gently, sand was also added until the depth reached 2 cm. A 30-ml slurry, composed of 6. 5 g of silica gel in 7:1 hexane/ethyl acetate was prepared.
The flask was swirled to make sure the silica gel was suspended in the solvent, and then the suspension was poured in the column. The stopcock was opened to let the silica settle and the solvent to slowly drain until the level of the top of the silica gel stops lowering.. Then a 2 cm layer of sand was deposited to protect the top surface of the column. The solvent was then drained down to the top of the sand. The entire solution of the product was then loaded in CH2Cl2 on the top of the column. The flow was then stopped adding the elution solvent 7:1 hexane/ ethyl acetate.
The column was then run at a flow rate of 3 drops/min. After 20 min the porphyrin pinkish color was collected. Visible spectroscopy The sample was prepared by placing 2 drops of tetraphenylporphyrin solution in a sample vial diluted to 4ml with additional 7:1 hexane/ ethyl acetate. A few drops of triethylamine were added to prevent any traces of acid. The UV/ visible spectral analysis of tetraphenylporphyrin was then performed to determine the absorbance of the molecule. Tetraphenylporphyrin was added till the absorbance at 420 nm is around 1 absorbance unit.
