Write the reaction equations: 1) alkane → chloroalkane → alkene → alkanol → alkene (for ethane)
Write the reaction equations: 1) alkane → chloroalkane → alkene → alkanol → alkene (for ethane) 2) alkane → bromoalkane → alkene → dichloroalkane → alkyne (for propane) 3) alkyne → alkene → alkanol → butadiene (for ethine) 4) alkane → chloroalkane → alkene → alkanol → alkene (for propane) alkane → bromoalkane → alkene → dichloroalkane → alkyne (for pentane)
No. 1 (for ethane).
For saturated hydrocarbons – alkanes – a substitution reaction is characteristic. Let’s write the equation for the reaction between ethane and chlorine. The reaction products are chloroethane and hydrogen chloride.
Н 3С – СН3 + Сl2 → C2H5Cl + HCl.
Ethylene will be obtained from monohalogenated derivatives under the action of an alcoholic alkali solution.
C2H5Cl + KOH → H2C = CH2 + KCl + H2O.
Ethylene is characterized by the reaction of hydration – the addition of water. The result is ethyl alcohol – ethanol.
H2C = CH2 + HOH → H3C – CH2OH
In the presence of concentrated sulfuric acid and when heated, ethyl alcohol undergoes dehydration (elimination of a water molecule), while converting into ethylene.
CH3 – CH2 – OH H2SO4 conc CH2 = CH2 + H2O (ethylene)
No. 2 (for propane).
As a result of the reaction between propane and bromine, bromopropane is formed.
Н 3С – CH2 – СН3 + Br2 → C3H7Br + HBr.
Under the action of alkali, bromopropane is converted to propene.
C3H7Br + KOH → H3C –CH = CH2 + KBr + H2O.
Propene, adding chlorine, turns into 1,2 – dichloropropane.
H3C – CH = CH2 + Cl2 → H3C – CHCl – CH2Cl.
1,2 – dichloropropane (dihalogenated) under the influence of an alcoholic alkali solution is converted into propyne.
H3C – CHCl – CH2Cl + 2KOH → H3C- C ≡ CH + 2 KCl + 2H2O.
No. 3 (for ethine).
Etine adds hydrogen – a hydrogenation reaction. It turns out ethene (ethylene).
HC ≡ CH + H2 → H2 = CH2.
Ethylene reacts with water to form ethyl alcohol (hydration reaction).
H2 = CH2 + H2O → CH3 – CH2OH.
Ethanol at a temperature of 450 0 C and in the presence of catalysts (aluminum and zinc oxides) is converted into butadiene -1.3, while the reaction proceeds with the elimination of water and hydrogen molecules).
CH3 – CH2OH → H2C = CH –CH = CH2 + H2O + H2.
No. 4 (for propane)
Н 3С – CH2 – СН3 + Cl2 → C3H7Cl + HCl (chloropropane and hydrogen chloride)
C3H7Cl + KOH → H3C –CH = CH2 + KCl + H2O (propene).
H3C –CH = CH2 + H2O → CH3 – CH2 – CH2OH (propanol).
CH3 – CH2 – CH2OH H2SO4 conc CH3 – CH = CH2 + H2O (propylene).
No. 5.
C5H12 + Br2 → C5H11Br + HBr (bromopentane and hydrogen bromide are obtained).
С5Н11Br + KOH → H3C – СН2 –СН2- CH = CH2 + KBr + H2O (reaction products – pentene and potassium bromide).
H3C – CH2 –CH2 – CH = CH2 + Cl2 → H3C – CH2 –CH2- CHCl – CH2 Cl (1,2 –dichloropentane).
H3C – CH2 –CH2- CHCl – CH2 Cl + 2KOH → H3C – CH2 –CH2- C ≡ CH + 2KCl + 2 H2O (pentin).
