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Question: What do the compounds \(2 - \)butanol and \(2 - \)butene have in common?...

What do the compounds 2−2 - butanol and 2−2 - butene have in common?

Explanation

Solution

Alkenes are part of the unsaturated hydrocarbons (comprised of only atoms of hydrogen and carbon) that include double bonds of carbon-to-carbon (C=C). Alcohols are substances that have a functional group called hydroxyl functional group (-OH) attached to the carbon atom belonging to any alkyl group.

Complete answer:
The compounds we are given are 2−2 - butanol and 2−2 - butene and we need to find what they both have in common. In order to do this we need to know what each of these organic compounds are;
Take 2−2 - butanol;

  • 2−2 - butanol, also known as sec-butanol, is a chemical compound that holds the molecular formula: CH3CH(OH)CH2CH3C{H_3}CH\left( {OH} \right)C{H_2}C{H_3}.
  • It has a -ol at the end of its name and −OH - OHin its structural representation, indicating that it belongs to the group of alcohols.
  • 2-butanol, colorless liquid is the secondary alcohol which is quite flammable. In organic solvents they are totally miscible and in three parts of water they are soluble.
    Take 2−2 - butene;
  • 2−2 - butene is a four-carbon atom composed acyclic alkene that has the molecular formula: CH3CHCHCH3C{H_3}CHCHC{H_3}.
  • It has an -ene at the tail end and a double bond between the two carbon atoms (C=CC = C) in its structural formula, indicating that it belongs to the alkene class.
  • Asphyxiate gas is a liquefied petroleum gas (which does not have any color), containing 2−2 - butene.
    Similarities:
    (i) Clearly both the organic compounds 2−2 - butanol and 2−2 - butene have the prefix ‘but-’. This prefix is an indication that any compound having ‘but-‘ will have only ‘four carbon’ atoms within its molecular formula. So this is a similarity since they both are definitely composed of only four carbon atoms.
    (ii) Looking at their possibilities of isomerism;
    - Since 2-butanol is asymmetric or chiral, it can be generated as one of two stereoisomers that is '(R)−(−)−2−\left( R \right) - ( - ) - 2 - butanol' and '(S)−(+)−2−\left( S \right) - \left( + \right) - 2 - butanol'. 'RR' is denoted for clockwise and 'SS' is denoted for anti-clockwise.
    - Even 2-Butene comes in the form of two geometric isomers that is it follows cis/trans-isomerism. Its two isomers are 'cis−2−- 2 -butene (\left( Z \right)$$$$ - 2 - butene)' and 'trans−2−- 2 -butene (\left( E \right) - $$$$2 - butene)'. Depending on the position of groups with higher priority, E and Z are given. E means the groups are placed at opposite sides of the double bond, while if it is placed on the same side then it is called as Z.
    So their similarity is that they both, 2−2 - butanol and 2−2 - butene have two forms of existence due to isomerism.

Note:
There exists a law according to the ‘Saytzeff rule’ that establishes a relation between 2−2 - butanol and 2−2 - butene. According to this rule, it is possible to perform dehydration on the alcohol 2−2 - butanol, to obtain 2−2 - butene as its primary product. This reaction also produces another minor product which is 1−1 - butene.