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| Phenol reactions in Organic chemistry |
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Phenol reactions in organic chemistry are also called phenolics. This is another name for it. This is a chemical compound which consists of hydroxyl group which is directly bonded to an aromatic hydrocarbon group. The simplest class is phenol (C6H5OH). Phenols are similar to alcohols. They have an unique property. They are not classified as alcohols. The acidities are higher because of the aromatic rings which are tightly couples with oxygen. Phenols have a relatively loose bond between hydrogen and oxygen. Phenols have more than two hydroxy groups which are bonded to the aromatic rings which are in the same molecule. The simplest examples of such are benzenediols which have two hydroxy groups on a single benzene group, but this change during phenol reaction.
Phenol reactions take place in a variety ways. Some of them are : Reaction of Esterfication and ether formation, Electrophilic aromatis substitutions, reaction of naphtols and hydrazines and sodium bisulfite, oxidative cleavage, oxidative de-aromatization with quinones which is also known as Teuber reation, phenols are oxidized to phediols, etc. These are some of the phenol reactions.
The combustion of phenol is a phenol reaction which burns in plenty of oxygen and gives carbon dioxide and water. But here the compounds contain benzene rings. Thus the combustion is hardly ever complete, especially if burnt in air. There is a high proportion carbon in phenol which means that it needs a higher proportion of oxygen to get completely combusted. Hydrogen in a molecule takes the oxygen which is available first. This leaves the carbon to form. Sometimes even carbon monoxide is formed if there is not enough oxygen. Phenol burns leaving a smoky flame which is full of carbon. This is an assorted phenol reaction.
Phenol reactions help in making esters. One can make esters from alcohols by reacting with carboxylic acids. Phenols are similar. But they react slowly with carboxylic acid. When phenol reacts with ethanol chloride at room temperature, the reaction is not as fast as ethanol chloride and alcohol. The formation of phenol ethanoate takes place with hydrogen chloride acid. It is necessary to make modification in the phenol first to make the reaction fast. Phenol reactions are slow.
How can we make esters for a phenol reaction? This needs an acid anhydride. This is ethnic anhydride, (CH3CO)2O. This acid reacts slower than corresponding reactions with acyl chlorides. You will need to warm the mixture. The phenol can react with sodium hydroxide solution which produces reactive phenoxide ion. Phenol and ethnic anhydride will form phenyl ethanoate with ethnic acid. This is not an important reaction but is similar to the manufacture of aspirin. In order to make the reaction faster, phenol should be first converted into sodium phenoxide by adding hydroxide solution. This is also another way to have phenol reactions.
Phenol reactions with Iron (III) ions forms strongle colored complexes. The colour may vary from compound to compound. This is also used as a test for phenol. Phenol reactions help in many reactions in organi chemistry.
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