yield of the pure product was determined to be 95.42%. PURPOSE 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. RESULTS The theoretical yield of the m-nitrobenzoate was de-termined to be 4.59 grams. 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 was 8 centimeters. Many reactants want to form the more stable product, whether that be in terms of sub-stituents (Markovnikov), or stability in terms of reduc-ing charges on the molecules. The more stable a product is, the quicker the reaction will take place, and the more stable product will also be formed in more quantity. This stability of charges comes into play while discussing ortho, para, and meta addition. Electron releasing groups (ERG) activate electrophilic substitution, and make the ortho and para positions negative, and are called ortho para directors In these reactions the ortho and para products will be created in a much greater abundance. Electron Withdrawing groups (EWG) make the ortho and para positions positive. The electrophile is positively charged, so it will not go to the ortho and para positions, but to the meta positions in greater abundance. Therefore, the majority of EWGs (with the exception of halogens), are meta directors. In this experiment a meta director is used. If the product added to the ortho or para positions would produce a carbocation intermediate that has a positive charge on a carbon that is directly touching the EWG. This carbocation intermediate has more energy, and is therefore less stable. Therefore, it is expected that the methyl meta-nitrobenzoate would be the product formed faster and in greater quantities because it has the more stable intermedi-ate. Thin layer chromatography uses a solvent (in this case 85% hexane–15% ethyl acetate) to separate dif-ferent products based on differences in polarity of the molecules. Typically more polar compounds will have more interaction with the stationary phase, and will not move as from the solvent front. This means that the less polar a substance is, the farther it will move. Using the mechanism o electrophilic benzylic substitution, it can be determined at where each step of the mechanism is occurring, and at
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
Depending on which face of carbonyl the hydride attacks, the ketone could result in two different diastereomers of product. Since the two ketone faces are nonequivalent, there will be stereo selectivity in reduction which means that one diastereomer will be more prevalent than the other. There are three reduction conditions can be used to reduce the 4-tert-butylcyclohexanone : NaBH4, MPV , and L-selectride. For NaBH4, the hydride attach itself to the carbonyl oxygen to become the hydroxyl group and it more likely from the top because the hydride isn’t blocked by a bulky group (Fig mech prez). Both sodium borohydride and lithium aluminum hydride are less bulky hydride reducing agents so it is expected that they will be able to attack from the top face of the molecule since the bulky tert-butyl group will not hinder the attack. For L-selectride mechanism is similar to NaBH4, the L-selectride is a source of hydride for the carbonyl oxygen but there are bulky groups that block the hydride. Since L-selectride is much larger and bulkier hydride reagent so likely not be able to attack from the top face in the presence of the bulky tert-butyl group (fig 1 and 2 like web) For MPV, the ketone is reduced with aluminum isopropoxide in isopropanol. The carbonyl oxygen attack the aluminum which causes the carbonyl oxygen to have a +1 charge, a hydrogen as
This paper describes the methods used in the identification, investigation of properties, and synthesis of an unknown compound. The compound was identified as calcium nitrate by a variety of tests. When the compound was received, it was already known to be one of twelve possible ionic compounds. The flame test identified the presence of the calcium anion in the compound. The compound tested positive for the nitrate cation using the iron sulfate test. At this point it was hypothesized that the compound was calcium nitrate. Reactivity tests and quantitative analysis comparing the unknown compound with calcium nitrate supported this hypothesis. Synthesis reactions were then carried out and analyzed.
The purpose of the experiment was to study the kinetics of the hydrolysis of ester, p-nitrophenyl acetate (NPA) that is catalyzed by the buffer imidazole (Im). In terms of kinetics, specifically speaking, the rate of reaction as determined by the concentration, reaction orders, and rate constant with each species in a chemical reaction. By using the concentration of the catalyst and the temperature, the overall reaction rate was determined. The rate constants of K0, Kobs, and Kcat can be derived via the plotting of the absorbtion at 400nm of p-nitrophenol vs. the concentration of the catalyst imidazole. Lastly, the free energy of activation, ΔGǂ, that is necessary to force the reactant’s transformation of the reactants to the transition state structure will be determined by using the equation ΔGǂ = ΔHǂ – TΔSǂ derived from the Eyring plot.
A double replacement reaction, also called a double displacement reaction, is a type of chemical reaction in which two compounds react, and the anions and cations of the two reactants switch places to form two new compounds (products). A general equation for a double replacement reaction would be: AX + BY → AY + BX, along with any states of matter subscripted after each compound. Simply put, a double replacement reaction is the exchange of positive ions, or cations, between two compounds to form two new compounds. A precipitation reaction is a double replacement reaction in which two aqueous reactants
The objective of part A was to determine the rate of the substitution reaction between 1-Chlorobutane and KOH. This information was obtained by using the titration method to record the concentration of KOH over a given amount of time. To start this procedure, 1-Chlorobutane was added to a round bottom flask, which was connected to a reflux apparatus. Once it was observed that reflux had started the KOH was added with EtOH; this is the start of the reaction. The aliquot was then titrated with 0.100 M HCl and the concentration was noted at each interval. By graphing the data one can determine the order of the reaction and the rate of the leaving group. This data will provide the type of the reaction, whether it is SN1 or SN2.
The distance of the initial extract line to a pigment band was divided by the distance of the marked solvent front to the initial extract line both were measured in cm. The RF (relative to front) was calculated for each pigment band, indicating the travelled distance between the pigment and the front (solvent line) on the chromatography
There is another type of mechanism called an elimination mechanism that is competing with the substitution mechanisms to attack the molecules. There are two types of elimination reactions, E1 and E2. E1 and SN1 mechanisms compete with each other as E2 and SN2 mechanisms compete with each other. To ensure that our experiment favors the substitution reaction, an environment must be created in which the leaving group, H2O, is a weak base and the nucleophile, bromine, has strong polarity. This is obtained in this experiment by adding sulfuric acid to the reacting solution. Sulfuric acid not only donates protons but also acts as a dehydrating catalyst to push the reaction more toward the products. Without sulfuric acid
The amount of methyl cinnamate was 1.4g. The percent yield was 1.4/1.52x100= 92%, atom economy was 162.19/148.2=1.09, and reaction efficiency was 0.92/1.09x100= 84%. The percent yield was shown to be less than 100 for several reasons: the reactants are failed to convert to product completely so that reactions are not completed, and it is not purified well. Overall, the result most likely shown to be successful since the percent yield was close to 100%.
During the Organic Molecules experiment, four reagents were used to test for the presence of three of the four basic categories of Organic Molecules, carbohydrates, lips, and proteins, in control substances and Cheerios. For carbohydrates, I was testing, specifically, for the presence of reducing (polysaccharides) and non-reducing sugars (monosaccharides). Carbohydrates, both reducing and non-reducing, are important to the cell because they act as an energy source and are an important factor in building and the structure of important sugars like Ribose. Monosaccharides are important, specifically, because they are sources of nutrients to cells. An example of this would be glucose. (Campbell, 2014, 68) Non-reducing sugars, such as starch, serve as storage for cells and are hydrolyzed and broken down when sugars are needed for the cell. Some polysaccharides, such as cellulose, are used for structural purposes in cells. In plants, cellulose is
Ensure gloves are worn at all times when handling strong acids and bases within the experiment of the preparation of benzocaine. 4-aminobenzoic acid (3.0g, 0.022 moles) was suspended into a dry round-bottomed flask (100cm3) followed by methylated sprits (20 cm3). Taking extra care the concentrated sulphuric acid of (3.0 cm3, 0.031 moles) was added. Immediately after the condenser was fitted on, and the components in the flask were swirled gently to mix components. It should be ensured that the reactants of the concentrated sulphuric acid and the 4-aminobenzoic acid were not clustered in the ground glass joint between the condenser itself and the flask. In order to heat the mixture to a boiling point, a heating mantle was used and then further left for gently refluxing for a constituent time of forty minutes. After the duration of the consistent forty minutes the rou...
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%).
Initially, 0.5mL of dimethyl maleate was used. The density of dimethyl maleate is 1.15g/cm3, resulting in an initial mass of 0.575g. The final mass of dimethyl fumarate was 0.386g, which gives a percent yield of 67.1%, which is greater
In the lab we added bromine (Br2) to trans cinnamic acid, which formed the product 2,3-dibromo-3-phenylpropanoic acid. This product could be in either Erythro form or Threo form. We know what form was produced based on the melting point. A high melting point, between 200 and 202 °C, or 115-160 °C for an impure form, means it is an erythro type. If the melting point of the product was between 80-91 °C it was a threo form compound. There are 2 places or centers on the molecule where the bromine could bond, which makes 4 stereoisomers possible in the reaction. The product could attack either anti or syn, and could attack to either the top or bottom side. Anti means the bromines would attack to the opposite sides, so they aren’t in the way of each other. Syn means on the same side, so both bromine’s
When benzoic acid paired with 1.0 M NaOH, it was observed that both compounds were soluble. Upon the addition of 6.0 M HCl into this solution, benzoic acid became insoluble. Benzoic acid was also insoluble in 1.0 M HCl. Ethyl 4-aminobenzoate was found to be insoluble in 1.0 M NaOH and soluble in 1.0 M HCl. But then, after adding 6.0 M NaOH into the test tube C (mixture of ethyl 4-aminobenzoate and 1.0 M HCl), a white powdery solid (undissolved compound) was formed. These demonstrate that both the acid and base became more soluble when they were ionized and less soluble when they were