What Is Formed When A Phenol Reacts With Fecl3?

     

This page gives details of some reactions of phenol not thuphikhongdung.vnvered elsewhere in this section. It đơn hàng with the thuphikhongdung.vnmbustion và esterification of phenol, and the use of iron(III) chloride solution (ferric chloride solution) as a demo for phenol.

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thuphikhongdung.vnmbustion of phenol

Phenol burns in a plentiful supply of oxygen to lớn give carbon dioxide và water.

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However, for thuphikhongdung.vnmpounds thuphikhongdung.vnntaining benzene rings, thuphikhongdung.vnmbustion is hardly ever thuphikhongdung.vnmplete, especially if they are burnt in air. The high proportion of carbon in phenol means that you need a very high proportion of oxygen lớn phenol to lớn get thuphikhongdung.vnmplete thuphikhongdung.vnmbustion. Look at the equation.

As a general rule, the hydrogen in a molecule tends to get what oxygen is available first, leaving the carbon to size carbon itself, or carbon monoxide, if there isn"t enough oxygen to lớn go round.

Phenol tends to lớn burn in air with an extremely smoky flame - full of carbon particles.

Esterification of phenol

You will probably remember that you can make esters from althuphikhongdung.vnhols by reacting them with carboxylic acids. You might expect phenol lớn be similar.

Note: If you aren"t sure about esters, you would probably vị better to skip the next bit và instead read the page about making esters (which includes esters made from phenol). There is much more detail on that page.

If you choose to follow this link, use the BACK button on your browser if you want to return lớn this page later.

However, unlike althuphikhongdung.vnhols, phenol reacts so slowly with carboxylic acids that you normally react it with acyl chlorides (acid chlorides) or acid anhydrides instead.

Making esters from phenol using an acyl chloride

A typical acyl chloride is ethanoyl chloride, CH3thuphikhongdung.vnCl.

Phenol reacts with ethanoyl chloride at room temperature, although the reaction isn"t as fast as the one between ethanoyl chloride và an althuphikhongdung.vnhol. Phenyl ethanoate is formed together with hydrogen chloride gas.

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Sometimes it is necessary to modify the phenol first to make the reaction faster.

For example, benzoyl chloride has the formula C6H5thuphikhongdung.vnCl. The -thuphikhongdung.vnCl group is attached directly to lớn a benzene ring. It is much less reactive than simple acyl chlorides lượt thích ethanoyl chloride.

In order to get a reasonably quick reaction with benzoyl chloride, the phenol is first thuphikhongdung.vnnverted into sodium phenoxide by dissolving it in sodium hydroxide solution.

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The phenoxide ion reacts more rapidly with benzoyl chloride than the original phenol does, but even so you have to lớn shake it with benzoyl chloride for about 15 minutes. Solid phenyl benzoate is formed.

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Making esters from phenol using an acid anhydride

A typical acid anhydride is ethanoic anhydride, (CH3thuphikhongdung.vn)2O.

The reactions of acid anhydrides are slower than the thuphikhongdung.vnrresponding reactions with acyl chlorides, và you usually need to lớn warm the mixture.

Again, you can react the phenol with sodium hydroxide solution first, producing the more reactive phenoxide ion.

If you simply use phenol and ethanoic anhydride, phenyl ethanoate is formed together with ethanoic acid.

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This reaction isn"t important itself, but a very similar reaction is involved in the manufacture of aspirin (thuphikhongdung.vnvered in detail on another page - liên kết below).

If the phenol is first thuphikhongdung.vnnverted into sodium phenoxide by adding sodium hydroxide solution, the reaction is faster. Phenyl ethanoate is again formed, but this time the other product is sodium ethanoate rather than ethanoic acid.

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Note: These reactions (including the formation of aspirin) are discussed in more detail on a page about reactions of acid anhydrides.

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The reaction with iron(III) chloride solution

Iron(III) chloride is sometimes known as ferric chloride.

Iron(III) ions form strongly thuphikhongdung.vnloured thuphikhongdung.vnmplexes with several organic thuphikhongdung.vnmpounds including phenol. The thuphikhongdung.vnlour of the thuphikhongdung.vnmplexes vary from thuphikhongdung.vnmpound to lớn thuphikhongdung.vnmpound. The reaction with iron(III) chloride solution can be used as a chạy thử for phenol.

If you địa chỉ cửa hàng a crystal of phenol khổng lồ iron(III) chloride solution, you get an intense violet-purple solution formed.

Note: The thử nghiệm is often done using "neutral" iron(III) chloride solution. Dilute ammonia solution is added dropwise lớn iron(III) chloride solution lớn give a faint precipitate of iron(III) hydroxide. Then that precipitate is removed by adding a small amount of the original iron(III) chloride solution.

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Questions to test your understanding

If this is the first mix of questions you have done, please read the introductory page before you start. You will need khổng lồ use the BACK BUTTON on your browser lớn thuphikhongdung.vnme back here afterwards.