Synthesis of carboxylic acids

Summary

This video offers an insightful overview of synthesizing carboxylic acids, a fundamental component in organic chemistry. It covers various methods, including oxidative cleavage of alkynes with ozone, oxidation of primary alcohols, and reactions involving Grignard reagents and nitriles. The video also touches on the conversion of carboxylic acid derivatives like esters, amides, and acid halides. The presenter promises detailed mechanisms and further exploration in subsequent videos, making it an engaging introduction for students and enthusiasts alike.

Takeaways

• 🔍 Carboxylic acids are often encountered as products of various reactions in undergraduate organic chemistry courses.
• 🌐 Oxidative cleavage of alkynes with ozone can yield carboxylic acids, with the specific acid produced depending on the alkyne's structure.
• 🍾 Primary alcohols can be oxidized to carboxylic acids using chromic acid or other oxidizing agents like potassium permanganate after neutralization.
• 🌿 The oxidation of alkyl side chains on benzene rings with chromic acid or potassium permanganate results in benzoic acid.
• 🧪 Grignard reagents can react with carbon dioxide to form carboxylic acids, with the mechanism involving nucleophilic addition to the carbonyl group.
• 💧 Aqueous acid workup of Grignard reagent reactions is necessary to protonate and generate the carboxylic acid.
• 🧩 Carboxylic acid derivatives such as esters, amides, acid halides, and nitriles can be hydrolyzed to yield carboxylic acids.
• 🔄 Nitriles can be synthesized from various compounds and serve as versatile precursors to carboxylic acids.
• 🌡 Hydrolysis of nitriles to carboxylic acids typically requires heat and acidic conditions.
• 🧲 Cyanide anions can act as nucleophiles in SN2 reactions with electrophiles to form nitriles.
• 📚 The video script provides a comprehensive overview of the synthesis of carboxylic acids, including mechanisms and various methods.

Q & A

What is the main topic of the video?

The main topic of the video is the synthesis of carboxylic acids in organic chemistry.

How does oxidative cleavage of alkynes with ozone lead to the formation of carboxylic acids?

Oxidative cleavage of alkynes with ozone leads to the formation of carboxylic acids when the alkyne is not symmetric, resulting in different carboxylic acids. If it's terminal, the carbonyl group is cleaved off, releasing carbon dioxide.

What is the role of chromic acid in the synthesis of carboxylic acids?

Chromic acid is used to oxidize primary alcohols to carboxylic acids. The process is detailed in videos on the oxidation of alcohols, including the types of oxidizing agents that can be used.

Why is the carboxylate anion formed during the oxidation of alcohols?

The carboxylate anion is formed because the oxidation process involves the removal of hydrogen atoms from the alcohol, which after neutralization with acids, results in the formation of a carboxylic acid.

How can alkyl side chains on benzene be oxidized to form carboxylic acids?

Alkyl side chains on benzene can be oxidized using either chromic acid or basic potassium permanganate to form benzoic acid, a type of carboxylic acid.

What is the sequence of events when a Grignard reagent reacts with carbon dioxide?

The sequence involves the reaction of the Grignard reagent with carbon dioxide, followed by neutralization with aqueous acid to produce a carboxylic acid.

What is the role of the carbonyl group in the reaction of Grignard reagents with carbon dioxide?

The carbonyl group in carbon dioxide acts as an electrophile, where one of the carbon-oxygen double bonds breaks during the nucleophilic addition by the Grignard reagent, forming a carboxylate anion.

Why is aqueous acid necessary in the workup of a Grignard reaction with carbon dioxide?

Aqueous acid is necessary to protonate the carboxylate anion formed in the reaction, converting it into a carboxylic acid.

What are the different types of carboxylic acid derivatives mentioned in the script?

The script mentions esters, amides, acid halides, hydrides, and nitriles as different types of carboxylic acid derivatives.

How can nitriles be synthesized from other compounds?

Nitriles can be synthesized from other compounds by reacting electrophiles with the cyanide anion, a nucleophile.

What is the significance of the reaction involving sodium cyanide and DMSO in the synthesis of nitriles?

The reaction involving sodium cyanide and DMSO is an SN2 type of reaction that allows for the synthesis of nitriles from a variety of other compounds.

What is the general process for hydrolyzing nitriles to form carboxylic acids?

Nitriles are generally hydrolyzed under acidic conditions and require heat to generate the carboxylic acid.

How can benzonitriles be synthesized from benzene diazonium chloride and copper cyanide?

Benzene diazonium chloride reacts with copper cyanide to form benzonitriles, which can then be hydrolyzed to produce carboxylic acids.

Outlines

00:00

🧪 Synthesis of Carboxylic Acids Through Oxidation and Reactions

This paragraph introduces the topic of carboxylic acid synthesis, focusing on the oxidative cleavage of alkynes with ozone and the oxidation of primary alcohols to carboxylic acids using chromic acid or potassium permanganate. It also touches on the oxidation of alkyl side chains on benzene to benzoic acid. The paragraph mentions the reaction of Grignard reagents with carbon dioxide, leading to the formation of carboxylic acids, and provides a brief overview of the mechanism involved, including nucleophilic addition and protonation to yield the final product.

05:02

🌐 Hydrolysis of Carboxylic Acid Derivatives and Nitriles

The second paragraph delves into the synthesis of carboxylic acids through the hydrolysis of their derivatives such as esters, amides, acid halides, and nitriles. It emphasizes the unique role of nitriles as they can be synthesized from various compounds and serve as versatile precursors to carboxylic acids. The paragraph outlines different methods to generate nitriles, including reactions with sodium cyanide and the use of diazonium salts with copper cyanide. It also discusses the hydrolysis process of nitriles under acidic conditions, which requires heat, and mentions that the mechanism will be covered in subsequent videos. The summary concludes by noting that this process is a valuable method for synthesizing carboxylic acids from a variety of starting materials.

Keywords

💡Carboxylic Acids

Carboxylic acids are organic compounds containing a carboxyl functional group (-COOH). They are central to the video's theme as they are the main topic being discussed. The script mentions various methods of synthesizing carboxylic acids, such as through the oxidative cleavage of alkynes, oxidation of alcohols, and hydrolysis of their derivatives.

💡Oxidative Cleavage

Oxidative cleavage refers to a chemical reaction where a molecule is broken down into two or more smaller molecules by the addition of oxygen. In the context of the video, the oxidative cleavage of alkynes with ozone is highlighted as a method to produce carboxylic acids, with the specific outcome depending on the structure of the alkyne.

💡Ozone

Ozone (O3) is a molecule consisting of three oxygen atoms and is a strong oxidizing agent. In the script, it is mentioned as a reactant in the oxidative cleavage of alkynes to form carboxylic acids, emphasizing its role in organic chemistry for breaking down unsaturated hydrocarbons.

💡Chromic Acid

Chromic acid is a solution of chromium trioxide (CrO3) in water, used as an oxidizing agent in organic chemistry. The video script explains its use in oxidizing primary alcohols to carboxylic acids, illustrating a common method for synthesizing carboxylic acids from alcohols.

💡Oxidation

Oxidation in organic chemistry involves the increase in the oxidation state of an atom or the addition of oxygen to a molecule. The script discusses oxidation as a key process in the synthesis of carboxylic acids from various precursors, such as alcohols and alkyl side chains on benzene.

💡Grignard Reagent

A Grignard reagent is an organomagnesium compound used in organic synthesis, typically prepared from an alkyl or aryl halide and magnesium. The script describes its reaction with carbon dioxide to form a carboxylic acid, demonstrating its utility in organic synthesis for creating new functional groups.

💡Nitriles

Nitriles are organic compounds with the functional group -C≡N. The video script notes that nitriles can be synthesized from various compounds and are precursors to carboxylic acids through hydrolysis, showcasing their importance as versatile intermediates in organic chemistry.

💡Hydrolysis

Hydrolysis is a chemical reaction involving the splitting of a compound by the addition of a water molecule. In the context of the video, hydrolysis of carboxylic acid derivatives, such as nitriles, esters, and amides, is discussed as a method to obtain carboxylic acids.

💡Esters

Esters are organic compounds derived from acids (or acid derivatives) and alcohols by esterification. The script mentions the hydrolysis of esters as a route to regenerate the parent carboxylic acid, illustrating the reversible nature of esterification.

💡Benzoic Acid

Benzoic acid is a carboxylic acid derivative of benzene and is mentioned in the script as a product of the oxidation of alkyl side chains on benzene. It serves as an example of how functional groups can be transformed into carboxylic acids.

💡Diazonium Salts

Diazonium salts are compounds containing the diazonium cation (-N2+) and are used in organic synthesis. The script describes the formation of benzene diazonium chloride and its reaction with copper cyanide to form benzonitrile, which can be hydrolyzed to benzoic acid, highlighting a complex synthetic pathway.

Highlights

Introduction to the synthesis of carboxylic acids in undergraduate organic chemistry.

Summary of reactions that produce carboxylic acids.

Oxidative cleavage of alkynes with ozone to form carboxylic acids.

Different carboxylic acids produced from symmetric and non-symmetric alkynes.

Oxidation of primary alcohols to carboxylic acids using chromic acid.

Types of oxidizing agents for alcohol oxidation, including chromic acid and potassium permanganate.

Formation of carboxylate anion and its conversion to carboxylic acid.

Oxidation of alkyl side chains on benzene to benzoic acid.

Grignard reagents' reaction with carbon dioxide to synthesize carboxylic acids.

Mechanism of nucleophilic addition of Grignard reagents to carbon dioxide.

Hydrolysis of carboxylic acid derivatives like esters, amides, and nitriles.

Synthesis of nitriles from various compounds using cyanide anion.

SN2 reaction of sodium cyanide with electrophiles to form nitriles.

Hydrolysis of nitriles under acidic conditions to generate carboxylic acids.

Copper cyanide reaction with aromatic diazonium salts to form aromatic nitriles.

Diazotization and coupling reactions as a method to synthesize nitriles.

Practical applications and versatility of nitriles as precursors to carboxylic acids.

Upcoming detailed discussion on the hydrolysis mechanism of nitriles.

Conclusion of the video on carboxylic acid synthesis.

Transcripts

hello in this video I'm going to talk

about the synthesis of carboxylic acids

by the time most people get to

carboxylic acids in an undergraduate

organic chemistry course you've probably

encountered them as the products of a

number of reactions and I'm going to

quickly summarize those kinds of

reactions and I'll talk about the

mechanisms where it's important Oh

one place where you encounter the

carboxylic acid is through oxidative

cleavage of alkynes with ozone all kind

of arrow I have a video on this reaction

of my series of videos on all kinds that

goes into more detail about how this

reaction works and how it's different

from the oxidative cleavage of alkenes

but basically if the alkyne is not Qura

to get to it the same carboxylic acid if

it's not symmetric you get different

carboxylic acids and cetera if it's

terminal the Karlin gets chewed off the

carbon dioxide so here's one way to make

carboxylic acids another way is through

you know there's other oxidation

reactions so for example primary

alcohols can be oxidized by chromic acid

and in my videos on the oxidation of

alcohols I've described this process in

some detail including the types of

oxidizing agents that can be used as

there are more than just chromic acid

generally I mean anything that chromic

acid does basic potassium permanganate

can do after you neutralize it so

I say permanganate sodium hydroxide this

reaction actually produces the

carboxylate anion which after your

neutralization with acids you'd have the

carboxylic acid over here

so oxidation works there are other

functional groups that can be oxidized

for example alkyl side chains on benzene

can be oxidized II begin both of these

methods work both chromic acid and basic

apps in permanganate will oxidize alkyl

benzene to benzoic acid and that

oxidation chews off some carbons if

they're there there's a pretty cool

reaction out there that is reaction of

grignard reagents never necessary didn't

I did not cover this reaction in and

migrated reagents review a series bill

probably or at least as of making this

video I haven't covered it it's probably

going to end up there in some detail but

I'm just gonna it's it's it's a quickie

so I'll share the the oval for you

overview and the mechanism so generic

grignard reagent i just want to get out

here the sequence of events one we react

it with carbon dioxide and then we we

neutralize that and you know sometimes I

will write water actually I tend to

prefer to white write aqueous acid to

work up a grignard reaction but in this

case it is required because we are

producing something that is acidic to

make sure we have acid to protonate it

from a mechanism standpoint here's our

our grignard reagent we know grignard

reagents react the carbonyl

electrophiles and honestly carbon

dioxide's like a molecule that has two

carbons coming off the same carbon

so we can here we go look kind of like I

want it to tool here fix that area and

so honestly you this this nucleophilic

addition occurs in very much the same

sort of way that you would expect one of

the carbon oxygen double bonds breaks

the other one stays together now we have

a carboxylate anion carboxylate anion is

not reactive further under these

conditions and so when you protonate it

using aqueous acid you generate the

carboxylic acid that's cool then

generally the the last kind of reaction

that synthesize carboxylic acid are the

hydrolysis of carboxylic acid

derivatives include esters amides acid

halides and hydrides and nitriles and

all of these reactions are going to be

covered in more detail in the subsequent

videos on those functional groups and

the types of Regents and things that are

needed but the nitriles are worth

particular note because hey crowds can

be synthesized from you know um from a

variety of other compounds because this

cyanide anion the nucleophile most of

the other carboxylic acid derivatives

are synthesized from carboxylic acids

talking about synthesizing carboxylic

acid from an ester when the ester was

made from the carboxylic acid originally

is a little bit in a circular and may be

counterproductive but because nitriles

can be generated from other

electrophiles by reacting those

profiles with cyanide nucleophiles so

here is just one example using let's say

sodium cyanide in DMSO so this is an sn2

for kind of reaction and our group Oh

get to my suck pool because I want to

show the carbon label air because I'd

like to do that then the night trials

are generally hydrolyzed under its

thorough aqueous acidic hydrolysis and

after this requires heat so even you

need a molecule that can withstand those

kinds of conditions but you can generate

the carboxylic acid for the nitrile

where you started from a halide or some

other leaving group and the sn2 is not

the only reaction that can get a Hydra a

cyanide are nuclei Oh

cyanide reacts without a heights and

ketones to make say no hydrants and that

video is in that reaction is covered

under the videos on their my videos

series on that topic and then copper

cyanide reacts with erring diet sodium

salts to make benzo night trials and so

there's another source there of night

trials that can be hydrolyzed to

carboxylic acids and converted into

other functional groups or here's the

Chris this fire hydrant thing and then

just is a one last reminder of how you

can go about making night trials

we react annalen with sodium nitrite and

hydrochloric acid and this converts

annalen into benzene diazonium chloride

is better than this diazonium salt can

react with copper cyanide to make bends

of nitrile you're not the only way to

make benzo nitrile but it is a way to

make them to micro and I'm going to

actually put this down here so it's not

hiding behind my head so my krauser can

be generated in a lot of ways which

makes them a useful precursor to

carboxylic acids I'm going to talk about

the mechanism of the hydrolysis of

nitriles

in the videos on night trials and I do

note that esters and other carboxylic

acid derivatives can also be hydrolyzed

to carboxylic acids so this concludes my

video on the synthesis of carboxylic

acids thank you for watching