The processing of crude oil involves key industrial steps such as fractional distillation, cracking, purification, and polymerisation.
Three of the fractions collected during the fractional distillation of crude oil are refinery gases, kerosene, and fuel oil.
(i) Identify which of these fractions has the highest viscosity.
(ii) Identify which of these fractions has the lowest boiling point.
(iii) Identify which of these fractions contains molecules with the most carbon atoms.
Industrial cracking is typically carried out under thermal or catalytic conditions.
(i) Name a catalyst used in industrial catalytic cracking.
(ii) One reaction that occurs in cracking involves the conversion of one molecule of pentadecane (C15H32\text{C}_{15}\text{H}_{32}C15H32) into one molecule of nonane (C9H20\text{C}_9\text{H}_{20}C9H20) and three molecules of an alkene. Complete the equation for this reaction.
C15H32→C9H20+‾ \text{C}_{15}\text{H}_{32} \rightarrow \text{C}_{9}\text{H}_{20} + \mathord{\underline{\quad\quad\quad\quad\quad}} C15H32→C9H20+(iii) State three distinct reasons why cracking is a vital process in the petroleum industry.
One of the compounds sometimes present as an impurity in crude oil is methanethiol, CH3SH\text{CH}_3\text{SH}CH3SH. Explain why it is important to remove this compound from a fuel before it is burned.
One compound obtained from crude oil is propene, which is used as a monomer in polymerisation. It has the following displayed formula:
HH∣∣H−C=C−CH3 \begin{array}{cc} \text{H} & \text{H} \\ | & | \\ \text{H}-\text{C} & = & \text{C}-\text{CH}_3 \end{array} H∣H−CH∣=C−CH3Complete the following structure to show two repeat units of the polymer formed from this monomer.
−C−C−C−C− -\text{C}-\text{C}-\text{C}-\text{C}- −C−C−C−C−
