organic chemistry synthesis of 2 chloro 2 methylbutane PDF

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This is a lab report focusing on the lab preparation for 2 chloro 2 methlybutane and preceeding data and calculations as well the the conclusions infred...

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1 Synthesis of 2-chloro-2-methylbutane

Synthesis of 2–Chloro–2-Methybutane Student Name Institution Course Name and Number Professor Date of Submission

2 Synthesis of 2-chloro-2-methylbutane

Introduction The major aim for this experiment was to prepare 2-Chloro-2-Methylbutane utilizing 2-Methyl-2-Butanol in combination of HCl in a SN1 mechanism reaction. SN1 is a substitution mechanism reaction which exhibits 1st order kinetics (Keller, and Kendall, 2017). The SNI rate is = k [E+] (Keller, and Kendall, 2017). This therefore implies that the determining rate step is unimolecular in which the rate equation is exhibited having first order dependence for the electrophile [E+] as well as zero-order dependence for the nucleophile. SN1 is a step by step process that could be inclusive of two or more states of transition and creation of a carbocation intermediate product which is sp2 hybridised trigon planar. This give ways for two varying pathways of approaching the nucleophilic attack that is the final step of the general reaction mechanism (Keller, and Kendall, 2017). In this experiment the nucleophile could initiate the attack from the top or even the bottom part resulting in equal quantities of racemization as well as two +enantiomers, since neither pathway is favored preferentially (Esselman, Hofstetter, Ellison, Fry, and Hill, 2020). The creation of the carbocation intermediate product is the determining rate step in the SN1. SN1 mechanisms preferentially leans towards tertiary carbons the most significant the carbon that the leaving group is linked to is also linked to three other groups (Esselman, Hofstetter, Ellison, Fry, and Hill, 2020). Secondary carbons equally go through SN1, but can also for E1 products as well. Primary & 1° carbons do not go through undergo SN1 mechanism. In the duration of this experiment the mechanism reaction mechanism happened in three steps. Firstly is the protonation of the group of OH on 2-Methyl-2-Butanol. This happens when the hydrogen that is a resultant of the HCl is cleaved off owing to the electronegativity of the Chlorine atom inside HCl. The OH group protonation creates H2O+ (Esselman, Hofstetter, Ellison, Fry, and Hill, 2020). The second step is inclusive of the group that leaves leaving. In the experiment the group leaving is H2O+, and is cleaved off of the carbon chain that now forms

3 Synthesis of 2-chloro-2-methylbutane

the carbocation intermediate which is sp2 hybridized trigonal planar. That is the determining rate step inside the overall reaction. Thirdly the final step consists of a nucleophilic attack as a result of Cl- forming 2-Chloro-2-Methylbutane. Purpose The main aim of this experiment was to syntesize an alkyl halide which is 2-chloro-2methylbutane through reacting 2-methyl -2-butanol (t-amyl alcohol) and hydrochloric acid. Alkyl halides are of huge interest in the field of organic chemisty since they are generally available and have varying benefits as well as detrimental impacts ( Keller, and Kendall, 2017). The generall reaction is as The reaction is SN1. The overall reaction is: CH3 CH3 CH3 C CH2OH + HCl  CH3 C CH2Cl CH3 CH3 + H2O

Reaction Mechanism

4 Synthesis of 2-chloro-2-methylbutane

First step: Protonation. Second step: Group that leaves exits, creation of Carbocation Intermediate determining rate step. Third step: Nucleophilic attack from ClProperties and Safety Compound

Boiling

M.W

Density

Hazard

2 chloro 2

Point 86

88.15

0.86

Irritant of skin

methyl butane

2 methyl 2

and eyes

102

106.6

0.805

butanol

Flammable Irritant of skin and eye Flammable

Hydrochloric

108.58

36.6

1.2

Irritant

5 Synthesis of 2-chloro-2-methylbutane

acid

Corrosive

Goggles and gloves are to be worn at all times during this experiment. Hydrocholic acid is a corrosive substance and cause irritation when it comes in contact with the skin or when ingested ( Houk, andd Liu, 2017). If one comes in to contact with the acid, the area must be rinsed with plenty of water. All acid spill must be neutralized using Sodium Bicarbonate and be wiped immediately. Gasses are released when the sodium bicarbonate is put in the funnel therefore, care must be taken not to put a stopper to the separator funnel ( Houk, andd Liu, 2017). The separator funnel should also be vented often when it is being shaken and should not be direct towards self or another person. Liquids could spill out during the process of venting. Chlorinated hydrocarbons are very toxic substances. The target vital organs such as the kidneys and the liver ( Houk, andd Liu, 2017). The substances and any resultant gasses should not be touched or inhaled. Apparatus 

25-mL flask ( round-bottom)



distillation head



condenser



thermometer



adapter (glass with rubber),



two water hoses,



two stands with clamps



room-temperature water bath



hot-water bath (250-ml beakers)



25-ml Erlenmeyer flask (with #0 rubber stopper)



rubber stopper (#1 or #2),

6 Synthesis of 2-chloro-2-methylbutane



glass stirring rod,



glass pipette



infrared (IR) spectrophotometer

Substances 

10Ml of 2-methyl-2-butanol



25 ml concentrated hydrochloric acid (HCl)



10ml drying agent (anhydrous Na2CO3)

Experimental Procedure 10 mL of 2-Methyl-2-Butanol was added to 25 mL of concentrated HCl in a separator funnel, the mixture was afterwards shaken and vented for about 10 minutes. The desired product was on the top layer. The desired product was then extracted and then washed following the steps listed below. The bottom layer was drained and then 10 mL of cold (NaHCO3) was then added and shaken and vented. The bottom layer was drained once more and afterwards 10 mL of NaCl was then added shaken and vented. The bottom layer was discarded once more and the top layer was poured into a clean beaker and dried utilizing anhydrous sodium sulfate. The desired product was afterwards transferred in to the vial and weight of product was measured for % yield. An IR was done and a silver nitrate & sodium iodide test were equally done to confirm the identity of the product and also the reaction mechanism.

Product Analysis (Instrumental and Qualitative)

7 Synthesis of 2-chloro-2-methylbutane

1Ml of 0.1M aqueous silver nitrate was added to the two test tubes. Four drops of the products was added to one of the testutves and four drops of 2 chlro 2 methybutane added to the other test tube. The results were then analysed. The product IR was then conducted. Data & Observations 2-Chloro-2-methylbutane: 9.267g Starting amoun of 2 mehtyl 2 butanol 10mL White precipitate recorded in the silver nitrate test No precipitate recorded in the NaI test

8 Synthesis of 2-chloro-2-methylbutane

9 Synthesis of 2-chloro-2-methylbutane

Calculations % Yield = (actual theoretical )*100 Mols 2-Methyl-2-Butanol = (10 mL)(.805g/mL) = (8.05g)(1mol/88.15g) = 0.091 mols Mols HCl = (25mL)(1.2g/mL) = (30g)(1mol/36.5g) = 0.822 mols Mols 2-Chloro-2-Methylbutane = (9.267)(1mol/106.56g) = 0.08697 mols % Yield = (0.08697mol / 0.091mol )*100 = 95.5714% Discussion and Conclusion Venting is is required sinceHCl posseses a high vapor pressure (Belachew, 2020).The water washing is get rid of any excessive HCl. The NaHCO3 washing is to neutralize any acid that may still be present. Since CO28 gas is also being produced, venting is required. Water was to get rid of the NaHCO3 and HCl that could still be in the mixture (Belachew,

10 Synthesis of 2-chloro-2-methylbutane

2020). The main aimof the experimentation was to syntesize the alkyl halide, 2-chloro-2methylbutane, utilizng the tertiary alcohol, 2-methyl-2-butanol; therefore undergoing an SN1 reaction. The percentage yied was calculated to be 95.5714. Following the reaction, a silver nitrate test was perfomed and it resulted in the formation of a white precipitate. The presence of the white precipitate was confirmation for the presence of 2 chloro 2 methyl butane (Belachew, 2020). The initial step was the mixing of 2 methly 2 butanol and hydrochloric acid in order for the protonation of the –OH group to occur (Coropceanu,, Arsene, Şargarovschi, and Purcel, 2019). This is due to the fact that the –OH group is a lesser leaving group while the – OH2 group is a more leaving group. The preceding stirring was so that every reactant in the mixture could come fully in to contact ( Keller, and Kendall, 2017). The capping shaking and venting was significant since there is buildup of pressure in the vial (Coropceanu,, Arsene, Şargarovschi, and Purcel, 2019). Water addition was so that the product could be washed. The organic layers occurred as a result of 2 chloro 2 methyl butane not being soluble in water as its density is less than that of water (Coropceanu,, Arsene, Şargarovschi, and Purcel, 2019). The NaHCO3 addition was to remove excessive HCL. Sodium bicarbonate neutralizes the HCL as it is a weak base. The NaCL addition was to remove excessive water after the hydrochloric acid and sodium bicarbonate reaction and was also to aid in the creating a separation between the organic and the inorganic layer. The percentage yield obtained was high with the owing to the efficiency in the washes. Silver nitrate is a salt that is soluble in water and when in reaction with an alkyhalide it results in the observation of a white precipitate. The white precipitate is AgCl(s) that is crash out. The IR of 2-Chloro-2-Methylbutane displayed higher and sharper and higher peaks which confirm the presence of negative electro atoms including chlorine. The goal of the

11 Synthesis of 2-chloro-2-methylbutane

experiment was therefore achieved owing to the high yield and the positive test conducted for the 2 chloro 2 methyl butane. References Belachew, W. (2020). Optimizing Pre-Service Chemistry Teachers Understanding in Reaction Related Concepts of Alipahtic Hydrocarbons. Eurasia Journal of Mathematics, Science and Technology Education, 16(9). Chisam, J. D., & Dunlap, N. (2019). Development of a Two-Week Discovery-Based Technique Lab for Undergraduate Organic Chemistry. Coropceanu, E., Arsene, I., Şargarovschi, V., & Purcel, Z. (2019). Efficient method of studying the intermediate reactions in the halogenation process of 2-methyl-butane in the course of organic chemistry. Acta et commentationes (Ştiinţe ale Educaţiei), 18(4), 46-55. Esselman, B. J., Hofstetter, H., Ellison, A. J., Fry, C. G., & Hill, N. J. (2020). SN1, E1, and E2 reactions of Tert-amyl compounds: improved analysis using computational chemistry and ASAP-HSQC NMR spectroscopy. Journal of Chemical Education, 97(8), 2280-2285.. Houk, K. N., & Liu, F. (2017). Holy grails for computational organic chemistry and biochemistry. Accounts of chemical research, 50(3), 539-543. Keller, V. A., & Kendall, B. L. (2017). Independent synthesis projects in the organic chemistry teaching laboratories: Bridging the gap between student and researcher. Journal of Chemical Education, 94(10), 1450-1457. Wu, N., Kubo, T., Sekoni, K. N., Hall, A. O., Phadke, S., Zurcher, D. M., ... & McNeil, A. J. (2019). Student-Designed Green Chemistry Experiment for a Large-Enrollment,

12 Synthesis of 2-chloro-2-methylbutane

Introductory Organic Laboratory Course. Journal of Chemical Education, 96(11), 2420-2425....