This question is about the production of squalane, a liquid alkane which occurs naturally in human skin and is used in cosmetics.
Suggest two properties that make squalane useful in cosmetics.
Give the molecular formula of squalane.
Squalane can be produced from squalene, an alkene present in shark liver oil, by reaction with hydrogen gas in the presence of a suitable catalyst.
(1)
Squalane used in cosmetic products must contain no more than 0.2 ppm by mass of catalyst.
Calculate the maximum permitted mass of catalyst in a product containing 50 g of squalane.
(1)
A reactor at 200 °C contains 8500 mol of liquid squalene, and hydrogen gas at a pressure of 4.0 × 105 Pa.
Under these conditions, the complete hydrogenation of squalene requires 500 m3 of hydrogen gas.
Calculate the number of C=C bonds in one molecule of squalene.
You must show your working.
[pV = nRT R = 8.31 J mol-1 K-1]
(4)
State symbols are not required.
(1)
Globally, 2.8 million dm3 of squalene is used each year.
Traditionally squalene was obtained exclusively from shark liver oil, which is a mixture of liquids.
The liver of a shark yields 300 g of squalene.
(1)
Calculate the minimum number of sharks that would be needed to produce 2.8 million dm3 of squalene.
[Density of squalene = 0.86 g cm-3]
(2)
Many large corporations now use squalane obtained entirely from plants.
Squalane can be obtained sustainably from corn starch with a yield of 23% by mass.
The production of 1 tonne of corn starch requires 0.093 hectares of land.
Calculate the area of land, in km2, required to produce 2500 tonnes of squalane from corn starch.
[1 tonne = 1000 kg 1 hectare = 0.01 km2]
(3)
The E-isomer of beta-farnesene can also be obtained from corn starch.
Explain why beta-farnesene exhibits geometric isomerism and has only two geometric isomers.
You may label the structure and use this in your answer.
(2)
(2)
The compound alpha-farnesene, C15H24, is a structural isomer of beta-farnesene.
The structural formula of alpha-farnesene is
(CH3)2C=CHCH2CH2C(CH3)=CHCH2CH=C(CH3)CH=CH2
(2)
(1)
Complete the diagram to show another structural isomer of C15H24.
(1)
Did this page help you?