Chemistry A2 Rings,acids and amines
- Created by: Andrei stephen
- Created on: 21-08-14 16:23
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- Chemistry A2 rings ,
- aldehydes and ketones
- they bothe contain a C=O functional group
- aldehydes have the general formula of C=OH
- the general formula for the ketone is R----C=O----R
- oxidation of alcohols
- primary and secondary alcohols can be oxidized by acidified potassium dichromate
- secondary alcohols when oxidised make ketones
- they can be reduced back into primary and secondary alcohols by NaBH4
- testing for aldehydes and ketones
- 2-4-dimethyl hydrazine (2-4-DNPH)
- tollens reagent
- this can be mixed with the aldehyde or ketone
- if it is an aldehyde it will make a silver mirror for a ketone their will be no reaction
- this can be mixed with the aldehyde or ketone
- carboxylic acids
- these can be used in all basic acid reactions
- acid + carbonate ---> salt +CO2 + H2O
- acid + base ---> H2 + salt + H20
- acid+alkali ---> salt+ H2O
- react with alcohols to make esters
- esters
- have a general formula of R--COOC--R
- has to have a conc H2SO4 cat
- they can also be made by acid anhydrides and Alcohols
- esters
- these can be used in all basic acid reactions
- hydrolysis of esters
- Acid hydrolysis is when you heat an ester with a dilute acid and makes a alcohol and a carboxylic acid
- alkali hydrolysis of esters
- heat ester with dilute NaOH to make a sodium salt and a alcohol
- Benzene
- benzene symbol is a hexagon with a circle this is because it is a resonance structure
- the circle represents the constant movement of electrons round the bonds the electrons form rings above and below the carbon rings
- due to the movement of these electrons it makes benzene very stable and due to this dense electron center it creates it repels nucleophiles
- so to attach functional groups you must first make them have a positive charge
- reactions of benzene
- halogenation
- must use an halogen carrier like AlBR3 or FeCL3
- these cause the halogen to become positive as such a substitution reaction can occur
- C6H6 + Br2 --AlBr3-->C6H5Br + HBr
- nitration
- you need to use an H2SO4 acid catalyst
- this is the equation
- When the NO2 group has been attached you can then reduce it using Sn and HCl acid concentrated at 50^oC
- friedel craft reaction
- this attaches CH3 groups to benzene in order to make methybenzene
- you need to use a catalyst like aluminum chloride
- the reaction is as follows
- one name for a benzene with a methyl group is Toluene
- halogenation
- benzene symbol is a hexagon with a circle this is because it is a resonance structure
- phenol
- a phenol is benzene with a OH group attached
- this makes benzene more reactive
- this means that you can attach other functional groups more easily
- for example you can attach halogen groups without needing a halogen carrier
- C6H5OH+3Br2------->C6H2OHBr3+3HBr
- you can also add nitro groups using dilute nitric acid
- C6H5--dilute HNO3>C6H4OHNO2
- phenols
- this is more reactive then benzene as the oxygen draws the electrons closer to it
- due to this higher reactivity halogens can react without a halogen carrier
- reaction with bromine
- C6H5OH+3 Br2-------->C6H2OHBr3 + 3HBr
- it will also react with nitric acid without a catalyst to make nitro phenol
- the reaction with nitric acid
- C6H5OH+HNO3-------->C6H4OHNO2+H2O
- Making azo dyes from phenols and properties
- first phenol is dissolved in with sodium hydroxide
- C6H5OH+NaOH------>C6H5O-Na+ +H2O
- this is then cooled and reacted with cold benzenediazonium chloride
- first phenol is dissolved in with sodium hydroxide
- other reactions of phenols
- combustion of phenols
- C6H5OH + 7O2 -----> 6 CO2+ 3H2O
- A very plentiful supply of oxygen is needed
- this is due to the carbon to hydrogen ratio as oxgen usaly reacts with hydrogen first leaving carbon to group together
- it can be used to make esters but you don't react it with carboxylic acids instead you react it with acyl chlorides or acid anhydrides instead
- acyl chloride reaction
- C6H5OH + CH3COCl -----> CH3COOC6H5 + H2O
- acyl chloride reaction
- you can react it with iron 3 chloride this will give you a violet colored solution
- this could be a possible test for phenols
- combustion of phenols
- making azo dyes from amines
- first you need to make nitric acid
- NaNO2 + HCl ------> HNO2 + NaCl
- then you react the nitric aid with phentolamine and hydrochloric acid
- C6H5NH2 + HNO2 + HCl----> C6H5N+ TRIPLE BOND N CL-+ 2H2O
- the product formed from this reaction is then reacted with phenol to make a azo dye
- C6H5N+ TRIPLE BOND N CLC6H5N+ TRIPLE BOND N CL- + C6H5OH ---->C6H5N+==NC6H5OH + HCl
- making azo dyes from amines
- first you need to make nitric acid
- NaNO2 + HCl ------> HNO2 + NaCl
- then you react the nitric aid with phentolamine and hydrochloric acid
- C6H5NH2 + HNO2 + HCl----> C6H5N+ TRIPLE BOND N CL-+ 2H2O
- the product formed from this reaction is then reacted with phenol to make a azo dye
- C6H5N+ TRIPLE BOND N CLC6H5N+ TRIPLE BOND N CL- + C6H5OH ---->C6H5N+==NC6H5OH + HCl
- THIS HAS TO BE DONE AT LOW TEMPERATURES
- first you need to make nitric acid
- THIS HAS TO BE DONE AT LOW TEMPERATURES
- first you need to make nitric acid
- aldehydes and ketones
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