In your discussion consider a SN2 reaction mechanism concept. Propose a modification of experimental procedure that would improv
e reaction yield. Give an example of another method of ether synthesis. Illustrate it with drawn reaction scheme; describe it in few sentences.
1 answer:
Answer:
Here's what I get
Explanation:
You may have done a Williamson synthesis of guaifenesin by reacting guaiacol with 3-chloropropane-1,2-diol.
A. Mechanism
Step 1
NaOH converts guaiacol into a phenoxide ion.
Step 2
The phenoxide acts as the nucleophile in an SN2 reaction to displace the Cl from the alkyl halide.
B. Improve the yield
You probably carried out the reaction in ethanol solution — a polar protic solvent.
You might try doing the reaction in a polar aprotic solvent— perhaps DMSO.
A polar aprotic solvent does not hydrogen bond to nucleophiles, so they become stronger.
C. Another method of ether synthesis —dehydration of alcohols
Sulfuric acid catalyzes the conversion of primary alcohols to ethers.
This is also a nucleophilic displacement reaction.
Protonation of the OH converts it into a better leaving group.
Attack by a second molecule of alcohol forms the protonated ether.
A molecule of water then removes the proton.
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The given question is incomplete. The complete question is as follows.
When 70.4 g of benzamide () are dissolved in 850 g of a certain mystery liquid X, the freezing point of the solution is
lower than the freezing point of pure X. On the other hand, when 70.4 g of ammonium chloride (
) are dissolved in the same mass of X, the freezing point of the solution is
lower than the freezing point of pure X.
Calculate the Van't Hoff factor for ammonium chloride in X.
Explanation:
First, we will calculate the moles of benzamide as follows.
Moles of benzamide =
=
= 0.58 mol
Now, we will calculate the molality as follows.
Molality =
=
= 0.6837
It is known that relation between change in temperature, Van't Hoff factor and molality is as follows.
dT = ,
where, dT = change in freezing point =
i = van't Hoff factor = 1 for non dissociable solutes
= freezing point constant of solvent
m = 0.6837
Therefore, putting the given values into the above formula as follows.
dT = ,
= 3.949 C/m
Now, we use this value for calculating i for
So, moles of ammonium chloride are calculated as follows.
Moles of
= 1.316 mol
Hence, calculate the molality as follows.
Molality =
= 1.5484
It is given that value of change in temperature (dT) = . Thus, calculate the value of Van't Hoff factor as follows.
dT =
i = 1.62
Thus, we can conclude that the value of van't Hoff factor for ammonium chloride is 1.62.
Answer:
See explanation below
Explanation:
In this case we have the starting reactant which is the ethine, In the first step reacts with NaNH₂, a strong base. This base will substract the hydrogen from one of the carbon of the ethine, and form a carbanion. This will react with the propane bromide, displacing the bromine and forming a 5 carbon chain with the triple bond on the carbon 1 and 2.
In the second step, reacts with the lindlar catalyst to do a reduction, and form a double bond between carbon 1 and 2. In essence, compound A is similar to compound B.
Finally B reacts with water in acid and makes a addition reaction, and form an alcohol.
The whole process can be seen in the picture below.
Hope this helps
