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Chemistry 2612 organic chemistry lab

Lab report #7

Synthesis of 2-chloro-2-Methylbutane from 2-methyl-2-Butanol Via SN1

04-6-2021

Introduction The purpose of this experiment is to synthesis 2-chloro-2-Methylbutane from 2-methyl-2Butanol Via SN1. The first set in the SN1 reaction is protonation which leads to the formation of carbocation intermediate, SN1 reaction allows rearmament of the molecule either H or R group to form the most stable product. SN1 reaction favors the formation tertiary substrate and secondary substate duo to hyperconjugation and inductive effect, methyl substrate doesn’t work well with SN1 reaction duo to the stability of carbocation. SN1 reaction stereochemistry is a 50/50 remixture which is also a multi-step mechanism and the rate of the reaction is unimolecular. SN1 reactions use polar protic solvents and SN1 involves weak nucleophiles. SN1 is first order with respect to the substrate and nucleophile. SN1 used in the experiment by Protonating 2-methyl-2-butanol using HCl making better leaving (H2O), lead to the formation of carbocation and nucleophile. The carbocation attacked by Nucleophilic attack using chlorine result information of 2-chloro-2-methylbtane.

Reaction Mechanism First step:

Second step:

Third step

Chemical Properties and Safety 2-chloro-2-methylbtane

Boing point =86°C Density= 0.866 g/cm3 Hazards include Irritant of skin, eyes, ingestion, and inhalation also flammable.

Sodium chloride

Boing point = 1,465°C Density= 1.2 g/mL Hazards include Irritant of skin, eyes, ingestion, and inhalation.

2-methly-2-butanol

Boing point =102°C Density= 0.8 g/mL Hazards include Irritant of skin, eyes, ingestion, and inhalation

Experimental Section 10. mL of 2-methyl-2-butanol and 25 mL of concentrated HCl added in a separatory funnel. Stopper and shake, swirl, and VENT for 10 minutes. The product(density is 0.86 g/mL) is the top layer which is washed and extracted by darning the bottom layer, 5-10 ml of cold sodium bicarbonate (NaHCO3) added to the mixture then swirl, VENT, and drain the bottom layer. 10 mL of water, swirl, vent, and drain the bottom layer than 10. mL of NaCl, swirl, vent, and drain the bottom layer again. The top layer poured out into a clean beaker and dried with sodium sulfate. Product is Transferred to obtain weight for yield then analyze by IR, then conduct the silver nitrate and sodium iodide tests.

Data and Observations

Calculation Percent Yield =

actual yield × 100% theoretical yield

10. mL of 2-methyl-2-butanol D =0.8 g/mL

10ml 0.8g x 1 1 ml

88.15g/mol

= 8g

8g 1 mol x = 0.091 1 88.15g

25 mL of concentrated HCl D= 1.2 g/mL

25ml 1.2g x 1 1ml 30g 1

x

36.458g/mol

=30g

1mol 36.458g

= 0.822

8.765g. 2-chloro-2-methylbtane

actual

106.59 g/mol

8.765 1mol x 1 106.59g

Percent Yield =

= 0.082

0.082 × 100% 0.091

= 90.11%

Discussion and Conclusions In conclusion, this experiment is conducted to synthesis 2-chloro-2-Methylbutane from 2-methyl-2-Butanol by SN2 reaction mechanism. The protonation of methyl-2-Butanol to which result in carbocation, then Nucleophilic attack which leads to the formation of 2-chloro-2Methylbutane. The product yield is 90% which is high, there must be error conduction in this experiment which leads to the failure of synthesis also Must be an error in the calculation of the theoretical value which produced such a high percentage. The HNMR of the 2-methyl-2-Butanol show singlet around 1.4ppm and 2-chloro-2-Methylbutane don’t have that singlet because it was attached to the OH which got protonated to form a better-leaving group. IN the IR test the OH peak around 3400 cm-1 disappeared after H-Cl reacted with 1-butanol to form 2-chloro-2Methylbutane which shows different peak forming....