Comparison of Three Isomers of Butanol
The Hydroxyl group on alcohols relates to their reactivity. This concept was explored by answering the question “Does each alcohol undergo halogenation and controlled oxidation?” . Using three isomers of butanol; the primary 1-butanol, the secondary 2-butanol and the tertiary 2-methyl-2-propanol, also referred to as T-butanol, two experiments were performed to test the capabilities of the alcohols. When mixed with hydrochloric acid in a glass test tube, the primary alcohol and secondary alcohols were expected to halogenate, however the secondary and tertiary ended up doing so. This may have been because of the orientation of the Hydroxyl group when butanol is in a different shape than 1-butanol. As hypothesised, when 1-butanol and 2-butanol samples were mixed with potassium permanganate in a test tube, signs of oxidation reactions resulted.
It is often discussed that various functional groups bare ability to change the physical and chemical properties of an organic molecule. There are many varieties of functional groups, for example; Hydroxyl (a simple group with oxygen and hydrogen bonded to one another resulting in high polarity) Carbonyl (with the presence of carbon double bonded to oxygen), Carboxyl (a group with carbon double bonded to oxygen and also to a hydroxyl group), and Amine (containing nitrogen bonded to what could be a variety of elements). Each of these groups provides specific properties that are vary depending on the quantity and orientation of the groups in the molecule. Alcohols in particular (organic compounds holding one or more hydroxyl groups) are known to be very reactive because of the presence of that group. Thus the purpose of this investigation was to verify the theories of how organic molecular structure affects the properties of the molecule in question. In this specific experiment, three different alcohols with the same molecular formula but varying structures were compared. Because of this relationship, these alcohols are isomers of each other. Specifically, Butanol, an alcohol with the molecular formula C4H9OH was used. The three isomers of this alcohol used were:
n-butanol (1-butanol) – Produced industrially from hydroformylation of propylene and then subsequent hydrogenation of the resultant butanal. It is used industrially to produce various butyl esters. It can also be formed naturally as a minor product of the fermentation of sugars, and thus found in many foods and beverages. It is a primary alcohol meaning the carbon to which the hydroxyl is attached only makes one other bond to a carbon.
2-butanol – flammable, colourless liquid. It is mainly produced on the pathway to producing the very popular industrial solvent: methyl ethyl ketone. It is a secondary alcohol meaning the carbon to which the hydroxyl is attached makes 2 other bonds to carbons.
T-butanol (2-methyl-2-propanol) – A very unique alcohol, Tert-Butanol holds titles as the simplest tertiary alcohol (tertiary because the carbon to which the hydroxyl is attached makes bonds with three other carbon atoms). It is also special as an alcohol in that it is usually a white crystalline solid at room temperature, with a melting point of 25°C.
The three alcohols of varying degree were tested for their ability to undergo oxidation and halogenation. It was hypothesized that the primary alcohol (n-Butanol) would be able to undergo oxidation, resulting in the aldehyde Butanal, the secondary alcohol would also do so, resulting in Butanone, but the tertiary alcohol lacking enough hydrogen atoms to produce water would not be able to undergo the reaction. As far as halogenation, the hypothesis was that the primary and secondary alcohols would be able to halogenate because of the abundance of hydrogen atoms to replace, and the tertiary alcohol conversely would not be able to produce the alkyl halide.
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