chapter 26 - compounds containing the carbonyl group Flashcards
What is an aldehyde
a C=O Group bonded at the end of a carbon chain
What is a Ketone
A C=O group In the middle of a carbon chain
What is a carbonyl compound
A carbonyl compound Consists of a carbon oxygen double bond.
Physical properties of carbonyl compounds
They are strongly polar, that a permanent dipole dipole forces between the molecules. These forces mean that boiling points are higher than those of alkanes.
Shorter chain aldehydes and ketones mix completely with water because hydrogen bonds form between the oxygen of the carbonyl compound and water
The reactivity of carbonyl compounds
The carbon oxygen bond in Carbonyl compounds is strong
This is because there is a big difference in electronegativity between the carbon and oxygen making the bonds strongly polar. So nucleophilic reagents can attack to the delta positive carbon. Also since they contain a double bonds, carbonyl compounds are saturated therefore addition reactions as possible.
Reduction of aldehydes and ketones
Many reducing agents will reduce both aldehydes and ketones to alcohols. One such reducing agent is sodium tetrahydridoborate(III). NaBH4.
Aldehydes ate reduced to primary alcohols and H plus acts as a nucleophile
Ketones are reduced to secondary alcohol is in a similar way
Physical properties of carboxylic acids
The carboxylic acid group can form hydrogen bonds with water molecules. Carboxylic acids up to 4 carbons are completely soluble in water.
They also form hydrogen bonds with each other in the solid-state therefore they have a much higher melting point then the alkanes of similar relative molecular mass.
One way of identifying a carboxylic acid is to measure its melting point and compare it with tables of no melting points. I thiele can be used.
What is an ester
an ester Is derived from a carboxylic acid. The hydrogen from the hydroxide group of the acid is replaced by a hydrogen group so the general formula is RCOOR1
What are the uses of esters
They are used as vegetable oils and they are also fats from animals
What is the difference between a fat and an oil
Fats are solid at room temperature while oils are liquid at room temperature.
What is propane -1,2,3- triol (glycerol)
Glycerol has three O-H bonds
It’s readily forms hydrogen bonds and is very soluble in water. It is a very important chemical in many industries and has a really wide range of uses
What are the uses of glycerol
It is used extensively in many pharmaceutical and cosmetic preparations because it attracts water, it is used to prevent appointments and creams from drying out.
It is used as a solvent in many medicines and is present in toothpastes
It is used as a solvent in the food industry for example, for food colouring
It is used to plasticise various materials
Tell me about biodiesel
One possible solution to the reliance on crude oil as a source of fuel for motor-
vehicles is is biodiesel.
To make biodiesel the oil is reacted with methanol (with a strong alkali as a catalyst) to form a mixture of methyl esters. Which can be used as a fuel in diesel vehicles with the little or no modification
What are the uses of acylation reactions
They are cheaper
They are less corrosive
They do not react with water as readily/easily
It is safer, as the byproduct of its reaction is ethanolic acid rather than hydrogen chloride (HCL)
One important use is the production of aspirin
how does Soap work step-by-step
1-Soap interacts between oil and water one clothes/skin are washed
2-Carboxylate ion and dissolves in water and the hydrocarbon end dissolves in oil
3-Soap ions arrange themselves around each drop of oil
4-Each droplet is now surrounded by a negative charge
5-The droplets then repel each other
6-each Charge/molecule forms and ionic interaction with delta H on water molecules
7-this Droplet is then carried away by flowing water
