Assessment: a. The percent yield was calculated as follows: 0.639g (actual) = 0.444 x 100% = 44.4% of the theoretical yield of 1.44g. b. The desired product is a white crystalline solid, which suggests that it does not have an absorption band around 400-800nm, indicating that the compound absorbs shorter wavelengths. To evaluate whether the system is conjugated, TLC should be used with the short wavelength of 254 nm. c. The melting point of the compound obtained was 75-90 degrees Celsius, indicating the presence of impurities. The melting point of the desired product, 1-cyclohexene-cis-1,2 dicarboxylic anhydride, is 102 degrees Celsius. The melting points of the reagents are lower than the product: 3-sulfolene has a melting point of 65 degrees Celsius, maleic anhydride is 52.6 degrees Celsius, and xylene has a melting point of 13.2 degrees Celsius. The wider and lower range of the obtained compound's melting point suggests the presence of impurities. d. No issues found. 0.09. The product formed from the reaction between maleic anhydride and butadiene is 1-cyclohexene-cis-1,2-dicarboxylic anhydride. This is evident from the HNMR signals, which show a multiplet at approximately 6.0 ppm with an integration of 2.00, another multiplet at around 3.6 ppm with an integration of 2.00, and a doublet of multiplets between 2.3-2.5 ppm, with one of the pairs having an integration of 2.27 and the other having an integration of 2.29. The solvent used was acetone, as indicated by the multiplet at around 2.05 ppm. A strong signal resembling a multiplet at around 0 ppm suggests that tetramethylsilane was used as the standard for 0 ppm. Traces of the starting materials, such as maleic acid, are present, as suggested by the singlet at around 7.3 ppm with an integration of 0.03. Additionally, there are traces of 3-sulfolene, indicated by the signal at 6.1 ppm with an integration of 0.09, and another signal at 3.72 ppm with an integration of 0.09.
The experiment of Diels-Alder reactions, in particular the furan and maleic anhydride as used in my experiment, observed the exo product as oppose to the exo product. This shows the tendency for the stereochemistry of the Diels-Alder to yield an exo product in preference to the endo product. To determine the stereochemistry, a melt temperature of the product was taken and compared to literature values. The melt temperature for the product was roughly around 113oC, corresponding to the exo Diels-Alder product of furan and maleic anhydride. When compared to the class data of melting ranges, the melting temperature from the reaction was relatively consistent to the majority. Based off this, the assumption can be made that the Diels-Alder prefers
The goal of this two week lab was to examine the stereochemistry of the oxidation-reduction interconversion of 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. The purpose of first week was to explore the oxidation of an alcohol to a ketone and see how the reduction of the ketone will affect the stereoselectivity. The purpose of first week is to oxidize the alcohol, 4-tert-butylcyclohexanol, to ketone just so that it can be reduced back into the alcohol to see how OH will react. The purpose of second week was to reduce 4-tert-butylcyclohexanol from first week and determine the effect of the product's diastereoselectivity by performing reduction procedures using sodium borohydride The chemicals for this lab are sodium hypochlorite, 4-tert-butylcyclohexanone
2-ethyl-1,3-hexanediol. The molecular weight of this compound is 146.2g/mol. It is converted into 2-ethyl-1-hydroxyhexan-3-one. This compounds molecular weight is 144.2g/mol. This gives a theoretical yield of .63 grams. My actual yield was .42 grams. Therefore, my percent yield was 67%. This was one of my highest yields yet. I felt that this was a good yield because part of this experiment is an equilibrium reaction. Hypochlorite must be used in excess to push the reaction to the right. Also, there were better ways to do this experiment where higher yields could have been produced. For example PCC could have been used. However, because of its toxic properties, its use is restricted. The purpose of this experiment was to determine which of the 3 compounds was formed from the starting material. The third compound was the oxidation of both alcohols. This could not have been my product because of the results of my IR. I had a broad large absorption is the range of 3200 to 3500 wavenumbers. This indicates the presence of an alcohol. If my compound had been fully oxidized then there would be no such alcohol present. Also, because of my IR, I know that my compound was one of the other 2 compounds because of the strong sharp absorption at 1705 wavenumbers. This indicates the presence of a carbonyl. Also, my 2,4-DNP test was positive. Therefore I had to prove which of the two compounds my final product was. The first was the oxidation of the primary alcohol, forming an aldehyde and a secondary alcohol. This could not have been my product because the Tollen’s test. My test was negative indicating no such aldehyde. Also, the textbook states that aldehydes show 2 characteristic absorption’s in the range of 2720-2820 wavenumbers. No such absorption’s were present in my sample. Therefore my final product was the oxidation of the secondary alcohol. My final product had a primary alcohol and a secondary ketone
...e 3. Both letters A and B within the structure of trans-9-(2-phenylethenyl) anthracene, that make up the alkene, have a chemical shift between 5-6 ppm and both produce doublets because it has 1 adjacent hydrogen and according to the N + 1 rule that states the number of hydrogens in the adjacent carbon plus 1 provides the splitting pattern and the number of peaks in the split signal, which in this case is a doublet.1 Letters C and D that consist of the aromatic rings, both are multiplets, and have a chemical shift between 7-8 ppm. 1H NMR could be used to differentiate between cis and trans isomers of the product due to J-coupling. When this occurs, trans coupling will be between 11 and 19 Hz and cis coupling will be between 5 and 14 Hz, showing that cis has a slightly lowered coupling constant than trans, and therefore have their respective positions in a product. 2
This experiment was divided into two main steps. The first step was the addition of bromine to trans-stilbene. Trans-stilbene was weighted out 2.00g, 0.0111mol and mixed with 40ml of glacial acetic acid in 100ml Erlenmeyer flask on a hot bath. Pyridinium hydrobromide perbromide of 4.00g, 0.0125mol was added carefully into the flask.
This is a contribution of the conjugated structure of the molecule that permits the absorption of the electromagnetic radiation in the visible spectrum of 400-700nm wavelength. In addition, the TPCP compound adopts a propeller shape in its three dimensional conformation. This can be described by the four phenyl rings are rotated out of the plane from the central ring due to the steric repulsion between the compounds. Lastly, after undergoing the synthesis process approximately 0.2 g of purified TPCP product was yielded. In other words, the theoretical yield was found to be 1.067 g, while the percent yield was determined to be 18.750%. (The calculations done to receive these digits could be found in the Calculations section of the article at the end of the article) The absorbance of the compound at 330 nm and 480 nm was predicted to be 1.1 and 0.2 respectively. Furthermore, the concentration of the TPCP using the equation displayed in the Calculations section at the end of the article was found to be 3.729*10-4 (330 nm) and 3.290*10-4 (480 nm).
The three butene products have been verified to elute in the following order: 1-butene, trans-2-butene, and cis-2-butene. Theory: The dehydration of 2-butanol, a secondary alcohol, progresses readily in the presence of a strong acid like concentrated sulfuric acid (H2SO4). The reaction is completed via the E1 mechanism. Initially, the hydroxyl group is a poor leaving group, but that is remedied by its protonation by the acid catalyst (H2SO4) converting it to a better leaving group, H2O. The loss of this water molecule results in a secondary carbocation intermediate that continues to form an alkene in an E1 elimination.
The overall objective of this experiment was to perform a Wittig reaction from creating an ylide and mixing it with a carbonyl (C=O) compound, cinnamaldehyde. The completion of the reaction was confirmed ultimately from the initial TLC analysis. Since TLC separates the components of the spotted material, as long as the retention factor values were different for cinnamaldehyde, the starting reagent, and the product(s), it was evident that some of the reaction had gone to completion. However, as seen in Figure 3, there was some blurred area between the product spots. This indicated that there still existed some impurities, most likely the starting reagent, which was affecting the movement of the compounds through the solvent, petroleum
Discussion The reaction of (-)-α-phellandrene, 1, and maleic anhydride, 2, gave a Diels-Alder adduct, 4,7-ethanoisobenzofuran-1,3-dione, 3a,4,7,7a-tetrahydro-5-methyl-8-(1-methylethyl), 3, this reaction gave white crystals in a yield of 2.64 g (37.56%). Both hydrogen and carbon NMR as well as NOESY, COSY and HSQC spectrum were used to prove that 3 had formed. These spectroscopic techniques also aided in the identification of whether the process was attack via the top of bottom face, as well as if this reaction was via the endo or exo process. These possible attacks give rise to four possible products, however, in reality due to steric interactions and electronics only one product is formed.
The purpose of this lab was to perform an electro-philic aromatic substitution and determine the identity of the major product. TLC was used to detect unre-acted starting material or isomeric products present in the reaction mixture.
As a final point, the unknown secondary alcohol α-methyl-2-naphthalenemethanol had the R-configuration since it reacted the fastest with S-HBTM and much slower with R-HBTM. TLC was a qualitative method and ImageJ served as a quantitative method for determining which reaction was the faster esterification. Finally, 1H NMR assisted in identifying the unknown from a finite list of possible alcohols by labeling the hydrogens to the corresponding peaks.
Reacting 1-butanol produced 2-trans-butene as the major product. 1-butanol produces three different products instead of the predicted one because of carbocation rearrangement. Because of the presence of a strong acid this reaction will undergo E1 Saytzeff, which produces the more substituted
Then the reaction tube was capped but not tightly. The tube then was placed in a sand bath reflux to heat it until a brown color was formed. Then the tube was taken out of the sand bath and allowed to cool to room temperature. Then the tube was shaken until a formation of a white solid at the bottom of the tube. After formation of the white solid, diphenyl ether (2 mL) was added to the solution and heated until the white solid was completely dissolved in the solution. After heating, the tube was cooled to room temperature. Then toluene (2 mL) was added to the solution. The tube was then placed in an ice bath. Then the solution was filtered via vacuum filtration, and there was a formation of a white solid. Then the product was dried and weighed. The Final product was hexaphenylbenzene (0.094 g, 0.176 mmol,
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.
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.