IndexAbstractIntroductionMethodsAcetylation reactionBromination reactionSpectroscopic tables of 4-bromoacetanilideDiscussionConclusionsAbstractThis experiment was completed with the aim of using green chemistry principles in the Analysis of the two-step organic synthesis of 4-bromoaceanilide. This experiment was relevant to the importance of green chemistry principles regarding the safety of the environment and human health. It was found that an adequate percent yield of 68% could still be achieved through the altered reaction sequence (Table 1). Both class and individual yields demonstrated that it is possible to perform the alternative, greener reaction and still obtain desirable results. Spectroscopic data were analyzed to confirm the identity of acetanilide and 4-bromoacetanilide. The alternative reaction proved to be the more optimal reaction than the standard one, thanks to the green chemistry principles it followed. These principles are important for human health and environmental protection, and the altered reaction used in the laboratory was a step in the right direction to make reactions chemically greener. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Introduction The purpose of this experiment was to use the principles of green chemistry to analyze the two-step organic synthesis of 4-bromoacetanilide. The standard reaction sequence discussed in this experiment produces harmful byproducts and waste.3 The cost of properly disposing of hazardous substances is high.2 Green chemistry principles are used to create a better, safer reaction sequence. In this experiment an acyl transfer reaction is used to form acetanilide from aniline. This acyl transfer reaction is used as a protecting group, which allows the acetanilide to undergo mono-substitution instead of multiple substitutions.1 Since acetanilide is more acidic, it will facilitate the reaction between HOCl and NaBr as these reactions are generally assisted by acid.4 This implements the green chemistry principles of prevention and use of less hazardous chemicals. The balanced equations for the two-step synthesis performed in the laboratory are shown below. The first reaction forms the compound acetanilide while the second forms 4-bromoacetanilide. Methods Acetylation reaction First, 2 ml (22 mmol) of aniline and 4 ml (69 mmol) of glacial acetic acid were mixed together in a dry and clean 25 ml round-bottom flask. A stir bar was incorporated into the mixture and the air condenser and adapter were attached to the flask. The mixture was brought to the boil at around 370-430 °C while stirring. During this period the movement of the condensation ring was carefully observed. When the condensation ring rose halfway up to two-thirds of the condenser, the heat dropped by 5-10°C. At this point the reaction was refluxed for 90 minutes and the height of the condensation ring was again carefully monitored. The reaction was removed from the heat after 90 minutes and cooled before being poured into 30 mL of cold ice water inside a 100 mL vessel. glass. This mixture was cooled and stirred in an ice water bath until crystallization was complete. The crystals were then collected with a Büchner filter and washed twice with 10 ml of ice water. Once the acetanilide crystals were dried, they were massed obtaining 1.808 g(61%) of a white solid: mp 108-111°C with decomposition [lit.5 mp 113-114°C]; IR 3291, 3067, 3027, 1662, 1499, 1262 cm-1; 1H NMR (500 MHz, CDC13) δ 2.16 (3H, s), 7.11 (1H, t), 7.31 (2H, m), 7.5 (2H, d), 7.65 (1H , s); 13C NMR (125.7 MHz, CDC13) δ 24.6, 120.1, 124.5, 129.1, 138, 168.8. Bromination reactionFirst of all, 1.0 g (7.4 mmol) of acetanilide was mixed with 1.8 g (17.5 mmol) NaBr in a 125 mL Erlenmeyer flask with 6 mL 95% ethanol, 5 mL acetic acid, and a stirring rod. This reaction was stirred in an ice water bath for 5 minutes. After completion, 10.7 mL (7.8 mmol) NaOCl was added to the mixture and the reaction was removed from the ice-water bath after stirring for an additional 5 minutes. After allowing the mixture to rest for 15 minutes, it was cooled again over an ice water bath. A solution of 1.0 g sodium thiosulfate added to 1.0 g sodium hydroxide in 10 mL distilled water was prepared. This preparation was incorporated into the reaction mixture and then mixed for 15 minutes. The crude product formed was then collected by vacuum filtration and washed with 10 mL of distilled water. Once dried, 50% ethanol was used to recrystallize the crude product. The recrystallized 4-bromoacetanilide product was collected and massaged obtaining 1.076 g (68%) of a white solid: mp 167-168°C with decomposition [lit.5 mp 167-169°C]; IR 3300, 3064, 2928, 1667, 1536, 1258 cm-1; 1H NMR (500 MHz, DMSO) δ 2.04 (3H, s), 7.47 (2H, d, J = 2.5 Hz), 7.57 (2H, d, J = 2.5 Hz), 10.06 (1H, s); 13C NMR (125.7 MHz, DMSO) δ 24.4 (2.04), 114.9, 121.3 (7.57), 131.9 (7.47), 139.1, 168.9. Table 1. The following table shows the yields and percentage yields of the class and individual data of the acetanilide and 4-bromoacetanilide products. It can be seen that the class average acetanilide yield was 1.84 grams while the individual yield was 1.808 grams. The lower individual performance is why the overall individual percentage performance is lower than the class value. The standard deviation of the acetanilide class yield was 0.23. This means that there was almost no deviation from the average, meaning that the individual performance was actually below average. The standard deviations of the percent class yields for acetanilide and 4-bromoacetanilide are 7.9 and 12.2, respectively. This means that there were a larger number of groups that deviated from the actual average, which shows that the individual percentage yields for both substances were comparatively similar to the average. Table 2. The following table shows the IR spectrum frequencies of acetanilide along with their assignments. The frequency at 3291 cm-1 was assigned to an NH bond, which is consistent with the NH bond that was part of the amide at the frequency of 1662 cm-1. This amide group also confirms the identity of the acetanilide product. Table 3. The following table shows the 13C NMR spectrum peaks for acetanilide in ppm along with the number of hydrogen atoms attached and peak assignments. The tree on the left of the table shows where each peak is assigned on the tree. The number of hydrogen atoms attached is consistent with the structure assignments for each different peak. This confirms the identity of acetanilide instead of 4-bromoacetanilide since there was 1 hydrogen atom attached to carbon 6, while in 4-bromoacetanilide there were 0 hydrogen atoms attached. Table 4. The following table shows the 1H NMR spectrum for acetanilide along with the structure that corresponds to the assignments. Peak values ​​in ppm are provided along with the number of hydrogen atoms attached to each different peak. The peak values ​​are consistent with the valuesprovided in the initial information. The amount of hydrogen atoms that correspond to each different peak is also consistent with its corresponding assignment in the acetanilide structure. The identity of acetanilide is further confirmed due to the hydrogen atom attached to the carbon at position E, while in 4-bromoacetanilide there was no hydrogen atom at that position. Spectroscopic Tables of 4-Bromoacetanilide Table 5. The following table shows the frequencies of the IR Spectrum of 4-bromoacetanilide along with their assignments. The frequency at 3300 cm-1 was assigned to an NH bond, which is consistent with the NH bond that was part of the amide at the frequency of 1667 cm-1. This amide group also confirms the identity of the product as 4-bromoacetanilide.Table6. The following table shows the 13C NMR spectrum peaks for 4-bromoacetanilide in ppm along with the number of hydrogen atoms attached and peak assignments. The tree on the left of the table shows where each peak is assigned on the tree. The number of hydrogen atoms attached is consistent with the structure assignments for each different peak. This confirms the identity of 4-bromoacetanilide instead of acetanilide since there are 0 hydrogen atoms attached to carbon 6, while in acetanilide there was 1 hydrogen atom attached. Table 7. The following table shows the 1H NMR spectrum for 4-bromoacetanilide along with the structure that corresponds to the assignments. Peak values ​​in ppm are provided along with the number of hydrogen atoms attached to each different peak. The peak values ​​are consistent with the values ​​provided in the initial information. The amount of hydrogen atoms corresponding to each different peak is also consistent with its corresponding assignment in the structure of 4-bromoacetanilide. The identity of 4-bromoacetanilide is further confirmed by the fact that there is no longer a hydrogen atom attached to the carbon which is now attached to the bromine, whereas in the acetanilide there was a hydrogen atom at that position. The COZY's pairing information is also displayed in the Mult. column. Table 8. The following table shows the HSQC data for 4-bromoacetanilide. 13C NMR peaks are shown along with corresponding 1H NMR peaks, if applicable. Only three 1H NMR peaks are shown because the final peak had a nitrogen atom attached rather than a carbon atom. This confirms the identity of the 4-bromoacetanilide product. DiscussionBoth reactions performed in this experiment demonstrate green chemistry principles. The main guiding principles shown are prevention, the use of less hazardous chemical syntheses, safer solvents and auxiliaries, efficiency, reduction of derivatives and intrinsically safer chemistry for the prevention of accidents.5 Prevention is an important principle to use in this discussion due to the change of experiments from the more dangerous standard procedure to the safer procedure actually performed. In this sense, the use of less hazardous chemical syntheses and safer solvents and auxiliaries are two key factors in the green chemistry analysis of this experiment. These factors show the negative qualities of the standard procedure and exemplify the positive qualities of the modified one. The efficiency can be checked in the standard procedure and will be explained in more detail later. The green chemistry principle of reduced derivatives manifests itself in the use of protecting groups in both reactions and for this reason is included in this discussion. The final guiding principle to discuss is the use of inherently safer chemicals for accident prevention. This principle can be used to examine how the modified reaction is chemically safer than thestandard procedure. These are the main guiding principles that can be used to analyze the two reaction sequences and their ability to be considered green. The first principle to discuss is prevention. In the standard procedure for the formation of 4-bromoacetanilide, HBr was produced as a byproduct along with the possibility of unreacted Br2 being present after completion of the reaction. This is a problem due to the fact that HBr is a strong and toxic acid, while Br2 is corrosive and toxic.5 These are not substances that are good to keep around after a reaction is complete. The altered reaction sequence, however, solves this problem. In the altered reaction, safer reagents are used to produce only water and NaCl as byproducts. Water can easily be returned to the environment and NaCl is a much safer alternative than Br2 or HBr. Therefore, the altered reaction sequence is chemically greener than the standard procedure regarding the prevention principle. Along the lines of prevention there are principles of use of less dangerous chemical syntheses and safer solvents and auxiliaries. The standard reaction uses materials such as acetic anhydride and bromine, which are reactive and toxic to humans and the environment. The standard reaction then generates more toxic and corrosive materials such as HBr and Br2. This demonstrates the standard reaction's total disregard for green chemistry. Even the materials used in the modified reaction sequence are not entirely safe and harmless. Bleach is used as a source of HOCl, instead of acetic anhydride. Being able to avoid acetic anhydride is beneficial, but bleach is also toxic to humans and the environment and can be deadly if mixed with the wrong substances. On the other hand, the altered reaction using NaBr as a reagent is positive due to its low toxicity. Again, the altered reaction also generates safer byproducts that are not as harmful as those produced in the standard reaction. Even with the use of bleach, the altered reaction is still considered chemically greener than the standard reaction sequence. Two principles of green chemistry that both reaction sequences show are efficiency and reduced derivatives. Aside from the production of toxic materials in the standard reaction sequence, both reactions work very well on their own.5 It is possible to obtain a high percentage yield from these reactions and obtain a pure compound that has a melting point almost identical to that reported in the literature value.3 Efficiency is an important part of green chemistry since less energy and resources need to be used to achieve the desired product. Both reactions also demonstrate the principle of reduced derivatives. One reagent used in both reaction sequences is aniline. Since aniline strongly activates the benzene ring to which it is attached, this can cause the ring to undergo numerous substitution reactions. This can be problematic as multiple substitutions can produce uncontrollable side products, which could cause various complications. To counteract this, the amino group can be acetylated, which would cause it to undergo only one mono-substitution. The acyl group serves as a protecting group in both of these reaction sequences. While SPGs help prevent additional byproducts and waste from being generated, they require an additional step, which goes against the principle of derivative reduction.1 The final principle of green chemistry used in the discussion is the use of intrinsically greener chemistry. safe for accident prevention. The purpose of this principle is to use substances that are relatively safe and that minimize the possibility that.