Chapter 6 (II) - Steven Flashcards
What are the reaction conditions for reacting a halogenoalkane to form an alcohol?
- Use warm aqueous potassium hydroxide
- Heat under reflux
What are the reaction conditions for reacting a halogenoalkane to form a nitrile?
- Heat under reflux
- Use potassium cyanide in ethanol
What is a nitrile?
When there is a triple bond between the C and N
What are the reaction conditions for reacting a halogenoalkane to form an amine?
-Warm with excess ethanolic ammonia
What is an amine?
Organic compunds based on ammonia (NH3), but one or more of the hydrogen atoms are replaced by alkyl groups.
When halogenoalkanes undergo elimination reactions, what do they form?
An alkene
What are the reaction conditions for when a halogenoalkane undergoes an elimination reaction?
- React with a warm alkali dissolved in ethanol
- Heat under reflux
When alcohols are dehydrated, what do they form?
Alkenes
What do you react alcohols with to form a chlorooalkane?
HCl or PCl5
How do you make an iodoalkane from an alcohol?
By reacting the alcohol with phosphorus triidide and then iodine
When halogenoalkanes are hydrolysed, what do they form?
Water
How do you compare the reactivities of halogenoalkanes?
1) Mix the halogenoalkane with water and silver nitrate solution, so that a silver halide precipitate is formed
2) Time how long it takes for the precipitate to form in each test tube
What happens to the rate of hydrolusis of halogneoalkens as you go down group 7?
It increases as bond enthalpy decreases
What hydrolyses the quickest, a primary, secondary or tertiary alcohol?
A tertiary alcohol
When you react alcohols with PCl5 or HCl what is produced?
A chloroalkane
When you react an alcohol with HBr, what is produced ?
A bromoalalkane
When you react an alcohol with red phosphorus and iodine, what is made?
An iodoalkane
When alcohols are dehydrated, what do they form?
Alkenes
What products are formed when an alcohol is refluxed with red phosphorus and iodine?
3RI + H3PO3
What do primary alcohols oxidise to?
Aldehydes and then to carboxylic acids
What do secondary alcohols oxidise to?
Ketones
What do tertiary alcohols oxidise to?
They don’t oxidise
What is the general formula of aldehydes and ketones?
CnH2nO
What is the difference between a ketone and an aldehyde?
Ketones have 2 alkyl groups attatched to the carbonyl carbon atom, whereas aldehydes only have 1
How can you test whether a compound is an aldehyde or a ketone?
-Benedicts solution will turn brick-red if it is an aldehyde’
How do you get just an aldehyde from a primary alcohol?
You need to get it out of the oxidising solution as soon as it is formed. You can do this by gently heating excess alcohol with a controlled amount of oxdising agent in distillation apparatus, so the aldehyde is distilled off immediately
How do you oxidise secondary alcohols into ketones?
Under reflux
What is the only way of oxidising tertiary alcohols?
By burning them
What does refluxing make sure?
You don’t lose any volatile organic substances
What problem does refluxing allow you to get around?
Organic compounds evaporating or catching fire before they have time to react
How does distillation work?
By gently heating a mixture, where the substances will evaporate out of the mixture in order of increasing boiling points
If a product and its impurities have different boiling points, what should you use to seperate them?
Distillation
What does separation do?
It removes any water soluble impurities from the product
When do you use separation?
If a product is insoluble
How do you do the process of separation?
1) Pour the mixture into a separating funnel and add water
2) Shake the funnel and allow it to settle
3) The organic layer and the aqueous layer should separate
What is meant by the term reflux?
A contnuous boiling,evaporation and condensation. It’s done to prevent loss of volatile liquids while heating
How can you remove traces of water from a mixture?
Add an anhydrous salt, such as calcium chloride which binds to any water present
