Section 4 Action of sodalime

2) Action of Sodalime: 1) Dry Heat: B) General Reactions: a-Change in appearance b-Degree of inflammability So it may be: *Nitration test: So it may be: c-Odor produced Comment: d-Residual Ash: Comment:   2) Action of Sodalime: On Cold: On Hot: Comment:

2) Action of sodalime Sodalime is a fused mixture of sodium hydroxide (NaOH) and calcium oxide (CaO) . Its main function is based upon the action of sodium hydroxide itself, while, CaO decompose or dehydrate the substance. Applied ONLY for solids and NOT applied for liquids

How to make sodalime action ? Mix one part of the substance with three parts of soda lime(1:3) and triturate this mixture in a porcelain mortar. Place the mixture in a dry test tube and add another layer of sodalime of the same thickness then heat from up to down. N.B: The upper layer of sodalime acts as a safe guard against escapement of any unreacted substance.

Actions of sodalime : a- Hydrolyzing agent (on cold &on hot) b- Decaroboxylation(on hot) C- Dehydrating agent(on hot)

Odors on cold : Amm odor : it may be an ammonium salt(hydrolysis) sweet odor of chloroform: it may be chloral hydrate.(hydrolysis) fishy odor of aniline :it may be aniline salt (hydrolysis)

Odors on hot 1.Amm odor: it may be amides or imides (hydrolysis) 2.Amm odor with bitter almond odor: it may be phthalimide or benzamide (hydrolysis) 3. Fishy odor : it may be anilides (hydrolysis) or amino acids (decarboxylation) 4.benzene odor :it may be benzoic acid , phthalic acid or their salts (decarboxylation) 5.Phenolic odor :it may be salicylic acid or its salt (decarboxylation) 6.Pleasant (styrene )odor :it may be cinnamic acid or its salt (decarboxylation) 7.Burnt sugar odor : it may be hydroxy aliphatic acid or their salt ,, carbohydartes, or salt of lactic acid .(dehydration)

a- Hydrolyzing agent Amm odor : Ex: a. on cold so it may be amm salts b.on hot so it may be amides or imides Ex:

2. Amm odor with bitter almond odor: due to the formation of benzonitrile with sodalime on heating. Ex:

3.Fishy odor: a.on cold so it may be aniline salts : Ex:

b.on hot so it may be anilide as acetanilinde or benzanilide :

4.pleasant sweet of chloroform on cold : so it may be chloral hydrate

b- Decaroboxylation : (on hot ) 1)Carboxylic and sulfonic acids on heating with sodalime giving the corresponding hydrocarbon or its derivative

2.Benzoic acid, phthalic acid, and their metallic salts (sodium or potassium) give the odor of benzene on heating. Salicylic acid or its salts give the odor of phenol. Cinnamic acid yields styrene odor (pleasant odor)

3) Amino acids e.g. and anthranilic and sulphanilic acids yield fishy odor of aniline on heating with sodalime.

C- Dehydrating agent(on hot) Burnt sugar odor on hot : so it may be: 1.carbohydrates or hydroxy aliphatic acids as tartaric acid or citric acid or their salts . 2. Salts of lactic acid (solid) ,not applied for lactic acid (liquid ) N.B Ammonium salts of hydroxy aliphatic acids give ammonia odor on cold due to hydrolysis , while it give burnt sugar odor on hot due to dehydration.

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