Alcohols and some of their Reactions Flashcards
what are alcohols
- a homologous series of compounds
- with the general formula CnH2n+1OH
what are alcohols usually the product of
halogenalkanes going through hydrolysis
what symbol is used to represent an alkyl group
R
using that symbol, what is the simplified formula of an alcohol
ROH
what is a primary, secondary and tertiary alcohol
- a primary alcohol has the OH group bonded to only one carbon atom or alkyl group
- a secondary has it bonded to two
- and a tertiary has it bonded to three
what would be the abbreviated formula for primary, secondary and tertiary alcohols
- for primary it is ROH
- for secondary it is R2CHOH
- for tertiary it is R3COH
what are the three reactions of alcohols covered in this section
- combustion
- conversions to halogenalkanes
- dehydration of alkenes
what is the equation for the complete combustion of ethanol
C2H5OH + 3O2 = 2CO2 + 3H2O
what do the conversions of halogenalkanes invlove
replacing the hydroxyl group in an alcohol molecule with a halogen atom
what is the other name of this reaction that could be used, but what is the catch
- halogenation
- but adding a halogen to an alcohol doesnt work
- so different methods are needed for each halogen
what is the chlorination of an alcohol carried out using
- phosphorus V chloride
- a white solid also known as phosphorus pentachloride
why does the reaction between an alcohol and phosphorus V chloride not need heating
because the reaction is very vigorous and exothermic itself
what are the two inorganic products in this reaction
hydrochloric acid and phosphorus oxychloride
what is the structural formula equation for the reaction between propan-1-ol and phosphorus pentachloride
CH3-CH2-CH2OH + PCl5 = CH3CH2CH2Cl + POCl3 + HCl
how is the chlorination of tertiary alcohols done
the alcohol is mixed with concentrated hydrochloric acid, by shaking, at room temp
what is used to carry out bromination
- a mixture of potassium bromide
- and 50% concentrated sulfuric acid
what is done to carry out bromination
the reaction mixture is simply warmed with with the alcohol
what are the two inorganic products that could be produced and the product you want from either reaction
- you can get either potassium hydrogensulfate or potassium sulfate
- however the product you want from both reactions is hydrogen bromide
what is the hydrogen bromide then used to do
react with the alcohol
what would be the equation of the reaction between hydrogen bromide and butan-1-ol
CH3-CH2-CH2-CH2OH + HBr = CH3-CH2-CH2-CH2Br + H2O
what is used to carry iodination out and how is it done
- a mixture of red phosphorus and iodine is used
- the reaction mixture including the alcohol is heated under a reflux
what do the two inorganic reagents from when they react and what is the equation for this
- phosphorus (III) iodide
- 2P + 3I2 = 2PI3
what would the equation for the reaction between phosphorus iodide and ethanol
3C2H5OH + PI3 = 3C2H5I + H3PO3
what is the name of the inorganic product produced in this reaction
phosphonic / phosphorous acid
how is the dehydration of alcohols carried out
by heating the alcohol with concentrated phosphoric acid
what happens during this reaction
- the OH group and a hydrogen atom from an adjacent carbon atom is removed
- causing a C=C bond to form between the carbon atoms
why is this reaction called dehydration
because water is the inorganic product
what are the equations for the dehydration of butan-2-ol, without having to include the phosphoric acid
- CH3-CH(OH)-CH2-CH3 = CH2=CH-CH2-CH3 + H2O
- CH3-CH(OH)-CH2-CH3 = CH3-CH=CH-CH3 + H2O
what is the difference between the two organic products
- the first one is but-1-ene
- the second one is but-2-ene
why are there actually three different types of organic products that could form from this reaction
- because but-2-ene has two different isomeric forms using the E-Z notation
- including the but-1-ene which only has itself, it makes three
what happens to the phosphoric acid in the reaction
the water mixes with it and dilutes it
