Aim The aim of this experiment was to prepare a pure sample of the organometallic compound ferocene. Introduction1 Ferrocene [bis( – cyclopentadienyl)iron] was the first compound of its kind to be discovered and gave rise to the class of organometallic compounds known as metallocenes. Ferrocene consists of iron metal coordinated to two cyclopentadienyl rings, one on each side of the metal. It was discovered accidentally by Pauson and Kealy, as they were trying to make fulvalene. More generally, these compounds can be classified as sandwich complexes. In a sandwich complex the metal centre lies between two pi bonded ligands. The metal centre in ferrocene is bonded to all 5 carbon atoms of the Cp ligand. To prepare ferrocene, the cyclopentadienyl …show more content…
The melting point range of the product was 167-172 OC. This is slightly below the literature value of 172-174 OC2, indicating that the product was not completely pure. The crude yield was 3.71g. The limiting reagent is the cyclopentadiene, and the reacton is 2:1 with respect to cyclopentadiene. Therefore the theorectical yield of ferrocene is 32.8 mmol. This yield is reasonable, however it must be noted that this was the crude yield before the product was purified by sublimation. At this point the crystals most likely still contained impurities and solvent, so this is not a true yield. One potential source of loss in this experiment is the cyclopentadiene. This usually exists in the form of a dimer, but is cracked by heating during distillation. It must be used fresh or it will redimerise. It is possible that some cyclopentadiene dimerised and therefore was not available for reaction, reducing the yield. Although ferrocene itself is air stable, the reaction was carried out in a nitrogen atmosphere as the reactants are air sensitive. If air was allowed to enter the system at some point, some reactant could have been destroyed, again lowering the …show more content…
This suggests that the background scan may not have run properly. However, all of the ferrocene peaks are still clearly visible. The most important peaks in this spectrum are the aromatic ones, which show that the cyclopentadienyl ligand retains its aromaticity on binding to the metal centre. The aromatic C-H peaks occur higher than the C-H stretch in an alkene, and there are also aromatic overtones at 1636 cm-1. The Fe-Cp stretch occurs at 471 cm-1 and is a single sharp peak, confirming that the iron is equally bonded to all 5 carbons of each ligand. The peak at 471 cm-1 also has a slight side peak at a higher frequency, which is the Cp tilt. A slight broad OH peak an be seen in the spectrum around 3500 cm-1. This shows that the sample still contained water. This fits with the melting point data, which showed that the ferrocene was not completely pure. Other than the water peak, the spectrum is quite clean, suggesting no other impurities. In test 2, sublimation is occurring. This is a method of purification where the ferrocene is heated so it goes into the gas phase without going through the liquid phase. It then solidifies and forms pure ferrocene crystals on the upper watch glass and leaves non-volatile impurities behind on the lower
The percent yield of products that was calculated for this reaction was about 81.2%, fairly less pure than the previous product but still decently pure. A carbon NMR and H NMR were produced and used to identify the inequivalent carbons and hydrogens of the product. There were 9 constitutionally inequivalent carbons and potentially 4,5, or 6 constitutionally inequivalent hydrogens. On the H NMR there are 5 peaks, but at a closer inspection of the product, it seems there is only 4 constitutionally inequivalent hydrogens because of the symmetry held by the product and of this H’s. However, expansion of the peaks around the aromatic region on the NMR show 3 peaks, which was suppose to be only 2 peaks. In between the peaks is a peak from the solvent, xylene, that was used, which may account to for this discrepancy in the NMR. Furthermore, the product may have not been fully dissolved or was contaminated, leading to distortion (a splitting) of the peaks. The 2 peaks further down the spectrum were distinguished from two H’s, HF and HE, based off of shielding affects. The HF was closer to the O, so it experienced more of an up field shift than HE. On the C NMR, there are 9 constitutionally inequivalent carbons. A CNMR Peak Position for Typical Functional Group table was consulted to assign the carbons to their corresponding peaks. The carbonyl carbon, C1, is the farthest up field, while the carbons on the benzene ring are in the 120-140 ppm region. The sp3 hybridized carbon, C2 and C3, are the lowest on the spectrum. This reaction verifies the statement, ”Measurements have shown that while naphthalene and benzene both are considered especially stable due to their aromaticity, benzene is significantly more stable than naphthalene.” As seen in the reaction, the benzene ring is left untouched and only the naphthalene is involved in the reaction with maleic
The theoretical weight was 599.6 mg. This yields a percent yield of 3.7%. Table 1 also illustrates the experimental melting point of 99.3-102.1◦C. A melting point that has a range larger than 3◦C is indicative of impurities in the sample. A few possibilities of impurities could have been unreacted norbornene, and water. Evidence that supports that there was unreacted norbornene in the final sample was the fact that the product was a jelly-like structure. Norbornene by itself has a jelly-like structure. However, once norbornene reacted with the acid-catalyst (H2O2), then it should have changed the chemical structure of the molecule and once the solution was brought back down to room temperature, crystals should have formed. Since a jelly-like, or oil-like product was present at the end of the reaction, then this is indicative that there was unreacted norbornene in the sample. The second impurity that may have been present in the final product was water. Instead of adding 3 mL of sodium bicarbonate and then 3 mL of brine, 3 mL of brine was added first and then 3 mL of sodium bicarbonate was added. This experimental error caused excess aqueous solution to be added to the diethyl ether. Since excess water was added to the final product, about 4x the amount of anhydrous sodium sulfate was needed in order to remove the water from the product. This was another indication that there was too much water in
Felder, M. Richard, Elementary Principles of Chemical Processes, 3rd ed.; Wiley: New Jersey, 2000; p 631.
water than last time, less products were formed, and most of the ester was used
The IR spectrum that was obtained of the white crystals showed several functional groups present in the molecule. The spectrum shows weak sharp peak at 2865 to 2964 cm-1, which is often associated with C-H, sp3 hybridised, stretching in the molecule, peaks in this region often represent a methyl group or CH2 groups. There are also peaks at 1369 cm-1, which is associated with CH3 stretching. There is also C=O stretching at 1767 cm-1, which is a strong peak due to the large dipole created via the large difference in electronegativity of the carbon and the oxygen atom. An anhydride C-O resonates between 1000 and 1300 cm-1 it is a at least two bands. The peak is present in the 13C NMR at 1269 and 1299 cm-1 it is of medium intensity.
The actual amount of crude product was determined to be 3.11 grams. The percent yield of the crude product was determined to be 67.75 %. The actual amount of pure product formed was found to be 4.38 grams. The percent yield of the pure product was determined to be 95.42%. Regarding the thin layer chromatography, the line from the solvent front is 8 centimeters.
The CFU/ml obtained for the dilution is >3 x 102 (Est.). For the second dilution that is 10-1, the viable cell form on the first plate is 190 colonies. The CFU/ml for this plate is 1.9 x 103 CFU/ml. for the second plate with same dilution, the viable cell form is 72 colonies. The CFU/ml for this second plate is 7.2 x 102. The range that the CFU/ml should be is 0-9×104 CFU/ml and the CFU/ml obtained is in the range (Salman and Hagar, 2013). For the third dilution, both of the dilution shows no growth of viable cell. The CFU/ml for the dilution is <1.0 x 102 CFU/ml.
In a small reaction tube, the tetraphenylcyclopentadienone (0.110 g, 0.28 mmol) was added into the dimethyl acetylene dicarboxylate (0.1 mL) and nitrobenzene (1 mL) along with a boiling stick. The color of the mixed solution was purple. The solution was then heated to reflux until it turned into a tan color. After the color change has occurred, ethanol (3 mL) was stirred into the small reaction tube. After that, the small reaction tube was placed in an ice bath until the solid was formed at the bottom of the tube. Then, the solution with the precipitate was filtered through vacuum filtration and washed with ethanol. The precipitate then was dried and weighed. The final product was dimethyl tertraphenylpthalate (0.086 g, 0.172mmol, 61.42%).
The isomerization procedure was done in order to create dimethyl fumarate from dimethyl maleate. Dimethyl maleate and dimethyl fumarate are cis and trans isomers, respectively. This procedure was done via a free radical mechanism using bromine. The analysis of carvones reaction was done in order to identify the smell and optical rotation of the carvone samples that were provided. The odor was determined by smelling the compound and the optical rotation was determined using a polarimeter.
Fractional Distillation and Gas Chromatography 6. Data and Results Reference Attached Pages 7. Discussion The purpose of this experiment was to identify the chemical constituents of an unknown solution and its ratio.
In order to separate the mixture of fluorene, o-toluic acid, and 1, 4-dibromobenzene, the previously learned techniques of extraction and crystallization are needed to perform the experiment. First, 10.0 mL of diethyl ether would be added to the mixture in a centrifuge tube (1) and shaken until the mixture completely dissolved (2). Diethyl ether is the best solvent for dissolving the mixture, because though it is a polar molecule, its ethyl groups make it a nonpolar solvent. The compounds, fluorene and 1, 4-dibromobenzene, are also nonpolar; therefore, it would be easier for it to be dissolved in this organic solvent.
Iron comes from the Latin word ferrum. From ferrum its symbol became Fe. The atomic number of iron is 26, and its atomic weight is 55.845. Iron is a magnetic, bendable, shiny white metallic element.
The anomalous temperature, 60°C, has been highlighted. red on the first graph. Here, the line can be seen clearly overtaking. the line at 70°C after 15 seconds, and the results at the 60°C are. anomalous as a result of the.
Mixed melting point was used to confirm the identity of the product. The smaller the range, the more pure the substance. When the two substances are mixed; the melting point should be the same melting range as the as the melting range obtained after filtering. If the mixed melting point is lower one taken from the crystals, then the two substances are different.
The expected melting point of Semicarbazone of Cyclohexanone is 166°C.1 The assumed product is Semicarbazone of Cyclohexanone. Observed temperature being lower than the expected may indicate a contamination or an impurity. The low temperature result was shown to be more accurate than the room temperature result. Perhaps, in the room temperature, there was more of a mix in the products (i.e. containing both Semicarbazone of Cyclohexanone and Furaldehyde). This is reinforced by the pale yellow colour observed, when Semicarbazone of Cyclohexanone is supposed to be white. Room temperature result could be close to the eutectic point. This is kinetic control, as it is formed much quicker than the product of the high temperature reaction. To fix the problem of lower than expected melting point could be have a set temperature as to how cold the low temperature should be (e.g.