2423L8
EXPERIMENT 8 – Reactions of Hydrocarbons
Properties and Identification of Hydrocarbons Purpose:
a) To identify saturated and unsaturated hydrocarbons using properties and reactions.
b) Study substitution and addition reactions.
Equipments test tube rack (1) test tube holder (2) 100 mL beaker medium test tube (6)
Materials cyclohexene toluene n-hexane conc. H2SO4 Br2/CCl4 or Br2/CH2Cl2
0.50 % KMnO4 10% NaOH 10% Na2CO3 unknowns hydrocarbons
Discussion
Hydrocarbons, compounds which contain only carbon and hydrogen, can be classified into several types, depending on their structure. Aliphatic hydrocarbons are divided into three classes: alkanes have only single bonds, and are said to be saturated; alkenes and alkynes have carbon-carbon double or triple bonds, and are said to be unsaturated. Aromatic hydrocarbons are cyclic compounds whose structure is related to that of benzene, with six -electrons in a six-member ring.
Aliphatic Hydrocarbons such as Alkanes are relatively inert to chemical oxidizing agents such as neutral or alkaline permanganate, where alkenes are readily oxidized at room temperature. The change in color can be used as a test for a double bond, provided the molecule contains no easily oxidizable group. Aromatic Hydrocarbons such as toluene will be used in each of the following experiments. Although formally unsaturated, C6H6CH3 in the sense that it has multiple carbon-carbon double bonds, toluene does not give the usual reactions expected of an alkene. It is not easily oxidized, and preferably undergoes substitution rather than addition reactions. Permanganate converts cyclohexene into a diol. Since a syn-hydroxylation takes place, the reaction is thought to involve the formation
Properties and Identification of Hydrocarbons Purpose:
a) To identify saturated and unsaturated hydrocarbons using properties and reactions.
b) Study substitution and addition reactions.
Equipments test tube rack (1) test tube holder (2) 100 mL beaker medium test tube (6)
Materials cyclohexene toluene n-hexane conc. H2SO4 Br2/CCl4 or Br2/CH2Cl2
0.50 % KMnO4 10% NaOH 10% Na2CO3 unknowns hydrocarbons
Discussion
Hydrocarbons, compounds which contain only carbon and hydrogen, can be classified into several types, depending on their structure. Aliphatic hydrocarbons are divided into three classes: alkanes have only single bonds, and are said to be saturated; alkenes and alkynes have carbon-carbon double or triple bonds, and are said to be unsaturated. Aromatic hydrocarbons are cyclic compounds whose structure is related to that of benzene, with six -electrons in a six-member ring.
Aliphatic Hydrocarbons such as Alkanes are relatively inert to chemical oxidizing agents such as neutral or alkaline permanganate, where alkenes are readily oxidized at room temperature. The change in color can be used as a test for a double bond, provided the molecule contains no easily oxidizable group. Aromatic Hydrocarbons such as toluene will be used in each of the following experiments. Although formally unsaturated, C6H6CH3 in the sense that it has multiple carbon-carbon double bonds, toluene does not give the usual reactions expected of an alkene. It is not easily oxidized, and preferably undergoes substitution rather than addition reactions. Permanganate converts cyclohexene into a diol. Since a syn-hydroxylation takes place, the reaction is thought to involve the formation