آزمایشگاه جداسازی وشناسایی ترکیبات آلی - شناسایی الدهید و کتون ها

آزمایشگاه جداسازی وشناسایی ترکیبات آلی

آزمایشگاه جداسازی وشناسایی ترکیبات آلی

In compounds containing carbonyl groups are operating, if the carbonyl groups with hydrogen atoms or alkyl groups is substituted, aldehyde (RCHO) or ketone (RCOR) are called. Chemical compounds in the carbonyl functional group is chemistry. The compounds identified by the characteristic functional group carbonyl reactions are possible. 


آلدهید و کتون

Aldehydes and ketones is to identify the different tests, there can be of them test 2and 4 - nitro phenyl hydrazine in the , chromic acid test, test Ydvfrm, Talnz test test test Fuchsin Benedict noted.

Test 2 and 4 -  nitro phenyl hydrazine:

Aldehydes and ketones with the reagent 2 and 4 - nitro phenyl hydrazine formation of the deposits are orange to red. The test for the detection of aldehyde and ketone other compounds are used. If the aldehyde or ketone Law to be tested if the red color of the precipitation trends will find.
تست 2 و 4 – دی نیترو فنیل هیدرازین

In the figure below represents the reaction between a ketone and 2 and 4 - nitro phenyl hydrazine reagent will see:

Method of preparation reagent 2 and 4 - nitro phenyl hydrazine:
1 g 2 and 4 - nitro phenyl hydrazine in 5 ml of concentrated sulfuric acid solution and the solution cautiously to 7 ml water and 25 ml add 95 percent ethanol. , it separated from the solids unresolved.

Methods to identify:
Two or three drops of liquid X (05 / 0 g of solid) in 2 mL of ethanol solution and drops of reagent 2 and 4 - nitro phenyl hydrazine add to it. Deposits formed on the orange to red because there is an aldehyde or ketone. Presence of conjugated double bond with the carbonyl group causes sediment to be red.

Talnz test or Tvlns:
Talnz test (Tvlns) Another practice that is used to detect aldehydes of ketones are used. Talnz reagent react with aldehydes (Tvlns) produced a silver mirror on the wall to test tubes.

Reaction in the form below to test Talnz (Tvlns) will see:
واکنش مربوط به تست تالنز
Reagent preparation method Talnz (Tvlns):

A solution of silver nitrate dissolving 3 g in 30 ml of water is available in soda solution and solution B is 10 percent. Reagent must be used immediately after preparation. Reagent for the preparation Talnz (Tvlns), one ml of solution A with one ml of solution B mix. Silver oxide deposits are formed. Then concentrated ammonia solution drop by drop to add to silver oxide deposits is resolved. Now reagent is ready for testing.

In the following reactions to prepare reagent Talnz (Tvlns) will see:
تهیه معرف تالنز

Note: Reactive Talnz (Tvlns) should be prepared and consumed during the remainder will be excreted within laundering. If the solution is maintained, the possibility of forming explosive Fulminating silver deposits there. This precipitated a mixture of silver nitride (Ag3N) and silver AZyd (AgN3) is.


5 0 / ml reagent Talnz (Tvlns) to 3 drops or 1 / 0 grams of Article X to add. Forming a silver mirror or black deposits indicate positive are tested. If did not perform reaction in normal temperature,heat in a little hot water temperature .

Note 1: If the test tube is not clean, silver, silver mirror to the wall of test tube is not formed, and to deposit or suspension appeared to be black.

Note 2: Some simple Ketons like acetone and methyl ethyl ketone also give positive response to the test.

Fuchsin Test:

in Fuchsin test  reagent should not be heated and  solution should not be alkaline. During tests on the unknowns, it is best seen as an known aldehyde used.


 Fuchsin reagent preparation method or indicator:
5 / 0 grams of pure Fuchsin (rosaniline hydrochloride) in 500 ml distilled water solution and the solution can smooth; 500 ml distilled water with sulfur dioxide, saturate, with a fully mixed solution of Fuchsin overnight and had to leave. This method, produces colorless reagent.

Fuchsin reagent in the form of infrastructure or Rvzanylyn hydrochloride can see:


2 ml of reagent Fuchsin - aldehyde in a test tube and poured a drop of aldehyde tested to add. Color produced in minutes See. (Eg willing to violet purple Bvtanal within 3 to 4 minutes to appear.) Reminded that the referral should not be heated.

Benedict test:

Benedict reagent, a reagent called by name an American chemist (Stanley Rossiter Benedict) is. Aliphatic Ldhydhay to identify (non-aromatic) no sulfur and alpha-hydroxy ketone is used. In response following an aldehyde and an alpha hydroxy ketone with Benedict reagent see:




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