Organic chemistry topic 17 ( aldehydes, ketones , carboxylic acids , esters,Acyl chlorides Flashcards
I want an aldehyde ? How do I make it ?
2
- distill and heat primary alcohol
- partial oxidation with potassium dichromate
- orange to greeen
How do I make a carboxylic acid?
?
2
- Reflux with potassium dichromate
- Primary ALCOHOL
- heat
- orange to green
Name all tests for aldehyde and ketone ?
4
1 ) fehlings and bens
2) Tollens
3) potassium dichromate
4) Brady’s
Positive test for Brady’s test ? What does it test for ? Condition? PPt? 4
- tests for carbonyl group = ketones and aldehydes
- dissolved in methanol , concentrated h2so4
- if it’s positive and aldehyde and ketone is present then = BRIGHT ORANGE PPt
What mechanism does the cyanide + aldehyde or ketone ? 1
- nucleophilic ADDITION
What reagents can we use for the cyanide reaction ?
2
- HCN
- KCN in cold alkaline solution
Positive test in fehlings and bens solution colour ?
1
- Blue to brick red
Outline tollens test ?
3
2 reagents and ppt?
- add silver nitrate and nh4cl should form a:
SILVER MIRROR PPT
When aldehyde is present
How do you form an Ester ?
3
- CONC ACID CATALYST ( HCL or h2so4)
- DISTILL CARB ACID + ALCOHOL
To obtain pure product you should:
Add na2co3 to remove any carb acid left( because it’s a reversible reaction )
How do we get a carb acid or alcohol from an ester?
4
What’s it called?
- REFLUX
- dilute hcl or h2so4
- acid hydrolysis
- reversible
How do we carry out base hydrolysis on an Ester ?
4
- REFLUX
- with weak base NAOH
- you get the carboxylate ion and an alcohol
- IRREVERSIBLE
How do we carry out triodomethane reaction ?
What does it test for ?
3
- tests for : methyl carbonyl group next to carbon
- add NAOH and I2 ∧heat
- yellow ppt should form for positive result
Why is the triodomethane reaction useful?
1
- shortens the carbon change by one
What mechanism is the liAlH4 reducing reaction ?
- nucleophilic addition
What is the liAlH4 ?
What does it do ?
- reducing agent
- converts the aldehyde and ketone back to the ALCOHOL !
How do I make ketone ?
3
A reflux secondary alcohol
Potassium dichromate
Orange to green
How can I oxidise a tertiary alcohol ?
1
Burn it
Solubility of carboxylic acids ( as the carbon chain increases) …
1
- the solubility decreases
Hydrolysis (acid) of Nitriles forms ?
- conditions ?
2
- Carboxylic acid + NH4CL
- reflux with dilute HCL