Cross Condensation of aldol 2015007632 Dowrie, K Contents Reaction 1 Introduction 1 Experiment Procedure 2 Experimental results 3 Table of calculations 3 Calculations 3 NMR 4 TLC 4 References 5 Reaction Introduction An aldehyde reaction is when aldehydes and keytones, both containing an α-hydrogen in the presence of an alkali group condenses and forms an enone. Acetone has α-hydrogens on each side. The proton can be removed and therefore giving a nucleophile anion. The aldehyde carbonyl is more reactive than the keytone and so it reacts rapidly with the anion. This product undergoes base catalysed hydration giving dibenzalacetone. Sodium hydroxide is a catalyst in the reaction because the NaOH reacts with water. Following this is then the …show more content…
While under the UV light the mixtures appeared a purple colour. The R_fValue Starting material: R_F=2.6/4.5 = 0.58 The sum: R_F=2.55/4.5 = 0.57 The reaction mixture: R_F=2.9/4.5 = 0.64 The final product: R_F=1.9/4.5 = 0.42 Table of calculations Benzaldehyde Acetone Sodium Hydroxide Ethanol Dibenzalacetone Co-efficient 2 1 1 1 1 Volume (ml) 4.04 1.5 30 Grams used (g) 4.2 1.185 4 0.95 2 Formula weight (g/mol) 106.12 58.08 40 46.07 234.29 Moles 0.0396 0.02 0.1 0.02 Moles/ Coefficient 0.02 0.02 0.1 0.02 Density 1.04 0.79 (1) Calculations Mass Impure compound mass: 2.02g Final compound mass: 2.88g Dibenzalactone = (4.2×234.29×1)/(106.12×2) = 4.64g (theoretical …show more content…
This process is to separate the substances within the compound. The compounds that are absorbed more travel less distance on the paper. The paper contains silica gel and the compounds stick to it as it travels up the paper. A very important aspect of TLC is to have a base line where all the compounds start from. As well as the ending line, where the solvent stopped. The higher the compounds go up the more polar the substance is. (1) On the TLC that was done in the practical 1 two lines had roughly the same distance of 2.55-2.6cm. The reaction material was higher of about 2.9cm and the final product was lower (1.9cm). This means that the reaction materials had a higher polarity than the other 3. The final product had the lowest polarity. The TLC drawing is
After 28 minutes, the mixture stopped boiling, and approximately 4.5 ml of bromobenzene was added drop by drop in the mixture, and color of the mixture was turned light brown orange. Then, the phenylmagnesium bromide was cooled in ice bath for a few minutes, and 10 ml of anhydrous diethyl ether was added in the mixture by using the syringe. After that, approximately 2.3 ml of methyl benzoate was added to the reaction, and it was added slowly slowly because the reaction was exothermic which needed to be cool in order to maintain a gentle reflux. Once all the methyl benzoate solution was added, the heating mantle was removed from the reaction flask and was cooled to the room temperature. During the reaction, a milky white salt began to precipitate, and the reaction flask was swirled for ten minutes until most of the reaction became visibly subdivided.
The better the leaving group, the faster the reaction making Br a better leaving group than Cl. Tertiary-butyl iodide reacts faster than tertiary-butyl bromide via S_N 2 mechanism because iodide is a better leaving group than bromide. True or False? True. 1-Chlorobutane (2.5 mL, d=0.886) in 20 mL of acetone is reacted with 90 mL of a 15 wt% solution of NaI in acetone.
It forms a complex with HBr and extracts it from the aqueous phase into the organic phase where the alkene is. This dehydrates the acid, making it more reactive so that the addition reaction is possible. Rapid stirring is required in order to maximize the surface area
Dehydration of 2-Methylcyclohexanol Sura Abedali Wednesday 2:00 PM January 31, 2018 Introduction: Dehydration reactions are important processes to convert alcohols into alkenes. It is a type of elimination reaction that removes an “-OH” group from one carbon molecule and a hydrogen from a neighboring carbon, thus releasing them as a water molecule (H2O) and forming a pi bond between the two carbons1. In this experiment, 2-methylcyclohexanol undergoes dehydration to form three possible products: methylenecylcohexane, 1-methylcyclohexene, and 3-methylcyclohexene in a Hickman still apparatus. Adding 85% Phosphoric Acid to protonates the “-OH” group, turning it into a better leaving group and initiating the dehydration reaction.
There are few vegetables and fruits that turns to the color brown if their surface is exposed to oxygen. Once the veggies or fruits been exposed to oxygen, then the browning begins to appear, and electrons and hydrogen will be removed. This happens because of an enzyme called catechol oxidase. The enzyme will act on its substrate catechol to form a yellow compound which then reacts with the oxygen in the air and change into benzoquinone. The more concentration of the enzyme, the more browning appears.
9. The melting point range was lower than the given range of the anti-addition product by 2 degrees Celsius. This could have been due to impurities in the product. A likely cause could have been water that still remained in the product after recrystallization (the product shifted upward during melting point analysis due to evaporation). Since water has a low melting point, it could have lowered the melting point range of the product.
For the orange, the distance the band traveled was 39mm and the distance solvent traveled was 39mm and the Rf was calculated at 1mm. For strawberry the distance band traveled 38mm and the distance the solvent traveled was 41mm and the calculated Rf was .927mm. The colors for strawberry, orange and grape Kool-Aid are made with food dye. There is also salt that is found in Kool-Aid that is why when placed in the tubes containing %NaCl, the solvent caused the drops on the strips to travel so far. The results in this were expected.
The yellow solution containing the reactants was slowly poured into the beaker containing the cold water and the acid in order to cause the precipitation of the alcohol, 9-fluorenol and to destroy (hydrolyzed) the unreacted excess sodium borohydride. Subsequently, the white precipitate was vacuum filtered and washed twice with 20.0 ml portions of distilled cold water by pouring the liquid into the Buchner Funnel during filtration. It was necessary to wash the alcohol prior to recrystallization considering that the C-OH bond is easily broken by the formation of a stable and benzylic carbocation that favors the synthesis of difluorenyl ether. Finally, before the purification by recrystallization of the obtained product, the white solid alcohol was allowed to dry over a period of a
Next, the oxygen is protonated from the 3-nitrobenzaldehyde, which is then followed by an elimination reaction where this acts as a leaving group. The product is the trans-alkene present in the product. After the reaction was completed, purification of the product was conducted using semi-microscale recrystallization.
Firstly, because the NaHCO3 compound was not stored in a sealed container, therefore dust particles could have changed the results, and making the product impure. Also, there are uncertainties associated with the instruments used in this experiment. This, if the products were measured slightly more than should be, this could have affected the concentrations of the solutions, and therefore causing a larger
The data table provided below obtained melting point data for crude product, pure product, and mixture of the pure and 4-tert-butylbenzyl. 12. The TLC data obtained is provided in a table below. The TLC data was conducted solely in a 9:1 hexane/ethyl acetate solvent solution as opposed to the 1:1 and pure hexane solution as well. This was due to the lack of time, but as explained in number 7, a very polar solvent (1:1 solution) or non-polar solvent (pure hexane) is not ideal when obtaining
C6H12 Possible side reactions: C6H6 + nH2 → cracking products C6H12 (benzene) ↔ C6H12 (methyl cyclo pentane) C6H6 + nH2 → C +
The final product weight for percent yield was only the solid E product, which missed one half of the final product produce. If both products were weight, the percent yield would have been larger that it was. Instead of 22.33%, it could have been 44.66%. To prove that both products were obtained, but only one of the two products was analyze, a TLC plate of the DCM layer, that contains both products, and of the final product, was obtain.
The actual data is the result on our experiment vs theoretical, which is based on the calculations above. I have also learned to pay more attention to draining out all of the product completely before continuing to test the experiment, as any small drop of contaminant can veer our results into a different
A small amount of sand was added after the layer of cotton. After that, a layer of silica filled almost 1/3 of the column. Finally, another small amount of sand was added just above the silica. The column was given a little tap with an aspirator to make the silica more compact. Figure 2.