Ch#17||Lec#6 |Grignard reagent, Organo metallic Compounds, Reactions & reactivity, preparation

Chemistry by Prof. Javed Iqbal2 minutes read

Grignard reagent, a vital organometallic compound in organic chemistry, is prepared by reacting Alkyl Halide with magnesium metal to form Alkyl Magnesium Halide, showcasing high reactivity due to its carbon-magnesium bond polarity. This compound is used to synthesize primary and secondary alcohols from ketones and carboxylic acids from carbon dioxide, highlighting its practical applications in organic synthesis.

Insights

  • Grignard reagent, a Nobel Prize-winning compound discovered by Victor Grignard, is vital in organic chemistry for creating unknown starting materials.
  • The reactivity of Grignard reagent, influenced by the alkyl group size, follows a specific order when interacting with alkyl halides, ultimately leading to the formation of primary and secondary alcohols through distinct reactions.

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Recent questions

  • What is a Grignard reagent?

    A Grignard reagent is an organometallic compound derived from Alkyl Halide by reacting with magnesium metal in dry ether. It is crucial in organic chemistry for synthesizing unknown starting materials due to its high reactivity.

  • Who prepared the Grignard reagent?

    Victor Grignard prepared the Grignard reagent in 1900, earning the Nobel Prize in 1911 and 1912 for its reactivity in organic chemistry.

  • What is the reactivity order of alkyl halides with Grignard reagent?

    The reactivity order of alkyl halides with Grignard reagent follows Iodide > Bromide > Chloride > Fluoride due to the derivative's alkyl nature.

  • What happens when Grignard reagent reacts with formaldehyde?

    When Grignard reagent reacts with formaldehyde, it results in the formation of primary alcohol, showcasing its practical applications in organic synthesis.

  • How does Grignard reagent react with ketone?

    Grignard reagent reacts with ketone to form secondary alcohol, specifically with propanone (also known as Dimethyl Ketone or Acetone). The reaction involves the use of dry ether as a solvent and the formation of a white compound.

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Summary

00:00

Grignard Reagent: Organic Chemistry Reactivity and Synthesis

  • Grignard reagent is a derivative of Alkyl Halide made by reacting light with magnesium metal, belonging to the organometallic compound family.
  • Victor Grignard prepared this compound in 1900, earning the Nobel Prize in 1911 and 1912 for its reactivity in organic chemistry.
  • Grignard reagent, also known as Alkyl Magnesium, is crucial in organic chemistry for synthesizing unknown starting materials.
  • Other organometallic compounds like Alkyl Lithium and Tetra Methyl/Ethyl Lead involve carbon bonded with metal, making them organic compounds.
  • Grignard reagent's preparation involves reacting Alkyl Halide with magnesium metal in dry ether to obtain Alkyl Magnesium Halide.
  • Impurity-free reactants and moisture-free solvents are essential in preparing Grignard reagent due to its high reactivity.
  • Grignard reagent's reactivity stems from the polarity of the carbon-magnesium bond, making it nucleophilic compared to the electrophilic nature of alkyl halides.
  • The reactivity of Grignard reagent varies based on the alkyl group, with smaller alkyl groups being more reactive.
  • The reactivity order of alkyl halides with Grignard reagent follows Iodide > Bromide > Chloride > Fluoride due to the derivative's alkyl nature.
  • Reacting Grignard reagent with formaldehyde results in the formation of primary alcohol, showcasing its practical applications in organic synthesis.

17:53

Grignard Reaction: Forming Secondary Alcohol and Acid

  • Grignard agent reacts with ketone to form secondary alcohol, specifically with propanone (also known as Dimethyl Ketone or Acetone).
  • The reaction involves the use of dry ether as a solvent and the formation of a white compound.
  • The reaction proceeds with the addition of ch3 MGBr to acetone, resulting in the formation of a ketone product.
  • Acidic hydrolysis is then carried out, leading to the formation of ch3c and ch3.
  • By replacing a methyl group with hydrogen, secondary alcohol can be produced.
  • Reaction with ethyl acetate results in the formation of territorial alcohol as the final product.
  • When the Grignard reagent reacts with carbon dioxide, carboxylic acid is formed, specifically acetic acid or ethanoic acid.
  • The process involves a two-step reaction, with the final product being acetic acid.
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