Order now In the experiment, 1-bromobutane was synthesized through the second order mechanism in the present of concentrated sulphuric acid and sodium bromide.
This is a second order nucleophilic substituition, SN2. As we know that the reaction required a nucleophilean electrophile and a leaving group in order to apply the experiment in nucleophile second order sustituition. We a few choices to make the OH- become better leaving group.
First, we react the alcohol with p-toluenesulfonyl chloride which will convert OH- into sulfonic acid ester to react with sodium bromide to produce 1-bromobutane.
Lastly, we are using a strong acid to protonate the OH - group in the presence of the bromide ionwhich changes the leaving group in the presence of the bromide ionwhich changes the leaving the group from hydroxide to waterand allows the bromide to react in the same mixture.
In this experiment we are using the third method to prepare the 1-bromobutane. We will separate and purify the product using simple distillation.
We will carry out a reaction with the specific purpose of making new compound which is a synthetic reaction. It is our responsibility to really understand the experimentcarefully. In this experimentsodium bromide and 1-Butanol are dissolved in water.
Sulphuric acid is added cautiously which generates hydrobromic acidwhich turn reacts with the alcohol upon heating to make 1- Bromobutane. SN2 reaction always occur in with inversion configuration at the substrate carbon.
The nucleophile approaches the substracte carbon from the back side with respect to the leaving group. In this experiment we are using water as an solvent which called as protic solvent because it has a hydrogen atom which it attached to a strongly to electroneagative element.
Hydrogen bonding encumbers a nucleophile and hinders its reactivity in a substituion reaction.
As we know alcohol do not undergo nucleophilic substituition reactions because hydroxide are ion is strongly basic and poor leaving group. The leaving group is is a group of atom which depart with the electron pair used to bond them with the substrate. Howeveralcohols readily undergo SN2 because the sulphuric acid was added which protonate the hydroxyl group in the presence of the bromide ion which chenges the leaving group from hydroxide to waterand allows bromide ions to react with it in the same mixture.
The sulphuric acid serves as two purposes which is to increases the amount of protonated alcohols present in the reaction mixture and to help tie up the water molecules generated in the reaction shifting the equilibrium in favor of the alkyl bromide.
An alternative and more covenient method involves the in situ generation oh hydrobromic acid by the addition of concentrated sulphuric acid to an aqueous soluition sodium bromide. From the calculationthe percatage yielid for this experiment is It is because while we are doing an experiment the set up of the distillation apparatus is not correct so small amount of gas from the ml round bottom flask was release to surrounding so we do not get an accurate an actual mass in this experiment.
We also need to wear gloves while doing an experiment because 1- Butanol and 1-Bromobutane both are flammable fluid which ca irritate our skin.
Sulphuric acid also very concentrated acid which can effect our skin. Makesure we wash our hand and gloves after handling the substances. The 1-Bromobutane was prepared from 1-Butanol. The theoretical yield for this experiment is The percentage yield is Graham Solomons and Craig B. FryhleOrganic chemistry international student versionTenth editionWiley publisherpage: Think what is in the aqueous solution?
Alkyl halide change from the top layer to the bottom layer at the point where water is used to extract the organic layer because the alkyl halide is denser compared to the water. What is the purpose of this wash? The purpose of this wash is to prevent the formation of polybrominated butanes from addition of any more bromine to the 1-bromobutane.
The bicarbonate reacts with the unreacted bromides to form Co2 and sodium bromide which is an inert salt. Why it is important that none of the solid CaCl2 be included in the final distillation of your 1-Bromobutane? Anhydrous CaCl2 has high affinity to waterso it will absorbed water surrounding.
It is important none of CaCl2 in final distillation because it can contaminated our product and can change the reading of melting point.Synthesis of 1-bromobutane. STUDY. PLAY. What are the three steps in which you can form 1 butanol into 1-bromo butane?
1) constant-boiling hydrobromic acid (47% HBr) (2) an aqueous solu- tion of sodium bromide and excess sulfuric acid, which is an equilibrium mixture containing hydrobromic acid; or. Butyl alcohol is a four carbon linear hydrocarbon that has a hydroxy group at position 1.
from MeSH 1-Butanol, which is also known as n-butanol or 1-butanol or butyl alcohol (sometimes also called biobutanol when produced biologically), is an alcohol with a 4 carbon structure and the molecular formula of C4H10O.
1-Bromobutane is the organobromine compound with the formula CH 3 (CH 2) 3 Br. It is a colorless liquid, although impure samples appear yellowish. It is a Boiling point: to °C; to °F; to K.
The SN2 reaction is responsible for taking 1-butanol and converting it to 1-bromobutane. SN2 and SN1 are reactions that take acids and catalyze them to create alkyl halides. Tertiary alcohols follow the SN1 reaction path and primary alcohols follow the SN2 reaction path.
In this experiment, sodium bromide and 1-Butanol are dissolved in water. Sulphuric acid is added cautiously which generates hydrobromic acid, which turn reacts with the alcohol upon heating to make 1- Bromobutane. 4. Changes were observed. Results: Preparation of 1-bromobutane from 1-butanol Mass of 1-butanol used = 0 g Mass of 1-bromobutane (dried) = 9.
g Percentage yield Observation during the course of reaction: two immiscible liquid formed, the one on the top is .