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Zorluk: ZorAlkanals and Alkanones: Oxidation, Reduction, and Distinction Tests

An organic liquid XX with the molecular formula C4H8OC_4H_8O forms a yellow precipitate when warmed with iodine in alkaline solution, but shows no observable reaction with Tollen's reagent. When compound XX is reacted with lithium tetrahydridoaluminate(III) (LiAlH4LiAlH_4) in dry ether, it produces compound YY. What is the IUPAC name of compound YY?

  1. Butan-2-olCevap
  2. B
    Butan-1-ol
  3. C
    2-Methylpropan-2-ol
  4. D
    Butanoic acid

Cevap

Butan-2-ol
The positive iodoform test shows the presence of a methyl ketone carbonyl group (CH3C=OCH_3C=O), while the negative Tollen's test confirms that compound X is a ketone (butan-2-one) rather than an aldehyde. Reducing a ketone with lithium tetrahydridoaluminate(III) (LiAlH4LiAlH_4) converts the carbonyl carbon to a secondary alcohol group, yielding butan-2-ol.

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1
Analyze the chemical test results to identify the functional group of compound XX.
Compound XX (C4H8OC_4H_8O) gives a positive triiodomethane (iodoform) test (yellow precipitate) but a negative Tollen's test (no silver mirror). This confirms that compound XX is a methyl ketone, specifically butan-2-one (CH3COCH2CH3CH_3COCH_2CH_3).
Alkanals reduce Tollen's reagent to silver metal, whereas alkanones do not. The positive iodoform test indicates the presence of a CH3C=OCH_3C=O carbonyl group.
2
Determine the reaction outcome when compound XX is reduced using LiAlH4LiAlH_4.
Reduction of the ketone butan-2-one with LiAlH4LiAlH_4 converts the carbonyl group (C=OC=O) into a secondary alcohol group (−CH(OH)−-CH(OH)-).
LiAlH4LiAlH_4 acts as a hydride donor reducing agent, turning alkanones into secondary alkanols.
3
Deduce the IUPAC name of the resulting product compound YY.
Reducing CH3COCH2CH3CH_3COCH_2CH_3 produces CH3CH(OH)CH2CH3CH_3CH(OH)CH_2CH_3, which is named butan-2-ol.
The four-carbon chain with the hydroxyl group at carbon-2 is named butan-2-ol.

Anahtar Kavram

Distinction between alkanals and alkanones via Tollen's and Iodoform tests, and reduction of ketones to secondary alcohols.
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Konular

Alkanals and Alkanones: Oxidation, Reduction, and Distinction Tests

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