Home >
Community >
Why does benzoyl chloride react preferentially with the phenoxide anion and not with water?
Upvote
13
Downvote
+ Chemistry
+ Organic chemistry
Posted by
Kane Cochrane
Why does benzoyl chloride react preferentially with the phenoxide anion and not with water?
Why does benzoyl chloride react preferentially with the phenoxide anion and not with water?
Implied in the question is that we want to prepare phenyl benzoate, and we want to depend on the reaction with benzoyl chloride being faster with phenoxide ion than with water.
I would not bet on it. Sure, phenoxide is a better nucleophile than water*, but its concentration is going to be far far less than water, which is presumably the solvent, right?
Me, I’d do the reaction between phenol and benzoyl chloride in chloroform. Don’t bother with converting the phenol to phenoxide. The reaction will be plenty fast and there won’t be any benzoic acid by-product (and wasted reagents). Maybe include a bulky base (like triethylamine) as an acid scavenger to absorb the HCl that is formed.
*That’s the straightforward answer to the question as asked, but the planned synthesis is fatally flawed with the presence of water.
Why does benzoyl chloride react preferentially with the phenoxide anion and not with water?
Implied in the question is that we want to prepare phenyl benzoate, and we want to depend on the reaction with benzoyl chloride being faster with phenoxide ion than with water.
I would not bet on it. Sure, phenoxide is a better nucleophile than water*, but its concentration is going to be far far less than water, which is presumably the solvent, right?
Me, I’d do the reaction between phenol and benzoyl chloride in chloroform. Don’t bother with converting the phenol to phenoxide. The reaction will be plenty fast and there won’t be any benzoic acid by-product (and wasted reagents). Maybe include a bulky base (like triethylamine) as an acid scavenger to absorb the HCl that is formed.
*That’s the straightforward answer to the question as asked, but the planned synthesis is fatally flawed with the presence of water.
nucleophilic acyl substitution at acid chloride requires a good nucleophile. Here, water being neutral molecule is a weaker nucleophile than phenoxide ion.
nucleophilic acyl substitution at acid chloride requires a good nucleophile. Here, water being neutral molecule is a weaker nucleophile than phenoxide ion.
Why does benzoyl chloride react preferentially with the phenoxide anion and not with water?
Implied in the question is that we want to prepare phenyl benzoate, and we want to depend on the reaction with benzoyl chloride being faster with phenoxide ion than with water.
I would not bet on it. Sure, phenoxide is a better nucleophile than water*, but its concentration is going to be far far less than water, which is presumably the solvent, right?
Me, I’d do the reaction between phenol and benzoyl chloride in chloroform. Don’t bother with converting the phenol to phenoxide. The reaction will be plenty fast and there won’t be any benzoic acid by-product (and wasted reagents). Maybe include a bulky base (like triethylamine) as an acid scavenger to absorb the HCl that is formed.
*That’s the straightforward answer to the question as asked, but the planned synthesis is fatally flawed with the presence of water.
Why does benzoyl chloride react preferentially with the phenoxide anion and not with water?
Implied in the question is that we want to prepare phenyl benzoate, and we want to depend on the reaction with benzoyl chloride being faster with phenoxide ion than with water.
I would not bet on it. Sure, phenoxide is a better nucleophile than water*, but its concentration is going to be far far less than water, which is presumably the solvent, right?
Me, I’d do the reaction between phenol and benzoyl chloride in chloroform. Don’t bother with converting the phenol to phenoxide. The reaction will be plenty fast and there won’t be any benzoic acid by-product (and wasted reagents). Maybe include a bulky base (like triethylamine) as an acid scavenger to absorb the HCl that is formed.
*That’s the straightforward answer to the question as asked, but the planned synthesis is fatally flawed with the presence of water.
More
VOTE
nucleophilic acyl substitution at acid chloride requires a good nucleophile.
Here, water being neutral molecule is a weaker nucleophile than phenoxide ion.
hence, the answer/
nucleophilic acyl substitution at acid chloride requires a good nucleophile.
Here, water being neutral molecule is a weaker nucleophile than phenoxide ion.
hence, the answer/
More
VOTE