Specific Methods For Organic Chemicals

1. Unsaturated bond:
(1) Bromine in carbon tetrachloride solution, the red color fades away. Misjudgment: Bromine has been extracted.
(2) Potassium permanganate solution, purple fading.
2. Alkynes containing acetylene hydrogen:
(1) Silver nitrate generates a white precipitate of acetylated silver.
(2) Ammonia solution of cuprous chloride generates a red precipitate of acetylated cuprous chloride.
3. Small cyclic hydrocarbons: Quaternary alicyclic hydrocarbons can make brominated carbon tetrachloride solution leg colored.
4. Halogenated hydrocarbons: Alcohol solution of silver nitrate, generating silver halide precipitates; The precipitation rate of different structures of halogenated hydrocarbons varies, with tertiary halogenated hydrocarbons and allyl halogenated hydrocarbons being the fastest, followed by secondary halogenated hydrocarbons, and primary halogenated hydrocarbons requiring heating to precipitate. You can determine which halogen it is based on the color of the precipitate.
5. Alcohol:
(1) Reacting with metallic sodium to release hydrogen gas (identifying alcohols with less than 6 carbon atoms).
(2) Using Lucas reagent to identify primary, secondary, and tertiary alcohols, tertiary alcohols immediately become turbid, secondary alcohols become turbid after placement, and primary alcohols remain unchanged after placement.
(3) The reaction between adjacent diol and copper ion produces a crimson blue precipitate.
6. Phenol or enol compounds:
(1) Produce color with a solution of ferric chloride (phenol produces blue purple).
(2) Phenol and bromine water form a white precipitate of tribromophenol.
7. Carbonyl compounds:
(1) Identify all aldehydes and ketones: 2,4-dinitrophenylhydrazine, producing yellow or orange red precipitates. Grignard reagent can also be used.
(2) To distinguish between aldehydes and ketones, the Toronto reagent is used. Aldehydes can generate silver mirrors, while ketones cannot.
(3) Distinguishing aromatic aldehydes from fatty aldehydes or ketones from fatty aldehydes, using Fehling reagent, fatty aldehydes generate brick red precipitates, while ketones and aromatic aldehydes cannot.
(4) Identify methyl ketones and structurally active alcohols, using a sodium hydroxide solution of iodine to generate a yellow iodoform precipitate.
8. Formic acid:
Using silver ammonia solution, formic acid can generate silver mirrors, while other acids cannot.
9. Amine: There are two ways to distinguish primary, secondary, and tertiary amines:
(1) React with benzenesulfonyl chloride or p-toluenesulfonyl chloride in NaOH solution, and the product generated by the primary amine is soluble in NaOH; The product generated by secondary amine is insoluble in NaOH solution; Tertiary amine does not react.
(2) Using NaNO2+HCl:
Fatty amines: Primary amines release nitrogen gas, secondary amines generate yellow oily substances, and tertiary amines do not react.
Aromatic amines: Primary amines generate diazonium salts, secondary amines generate yellow oily substances, and tertiary amines generate orange yellow (acidic conditions) or green solids (alkaline conditions).
10. Sugar:
(1) Monosaccharides can react with both Toren and Fehling reagents to produce silver mirror or brick red precipitates.
(2) Glucose and fructose: Bromine water can distinguish between glucose and fructose. Glucose can cause bromine water to fade, while fructose cannot.
(3) Maltose and sucrose: Using Toluene or Fehling reagents, maltose can form silver mirror or brick red precipitates, while sucrose cannot..