Phytochemistry Lecture 4: Oxygenated Compounds
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Questions and Answers

What is the melting point of geraniol derivative?

  • 52 - 53 °C
  • 82.2 °C (correct)
  • 20 - 25 °C
  • 35 - 40 °C
  • Which of the following statements about citronellol is true?

  • It is stable due to having only one double bond. (correct)
  • It is optically inactive.
  • It contains two double bonds in its structure.
  • It is commonly used for its citrus scent.
  • Which product is known to contain nerol?

  • Oil of lavender
  • Oil of rose
  • Oils of neroli (correct)
  • Oil of citronella
  • What characteristic do geraniol and nerol share?

    <p>Both have esters that occur with them.</p> Signup and view all the answers

    What odor is commonly associated with citronellol?

    <p>Rose-like odor</p> Signup and view all the answers

    What is a primary use of Linalol?

    <p>In the flavor industry</p> Signup and view all the answers

    Which of the following is the most common isomer of Menthol?

    <p>l-menthol</p> Signup and view all the answers

    What percentage of Menthol is typically found in oil of Japanese mint?

    <p>75 - 90 %</p> Signup and view all the answers

    Which method is primarily used for isolating Menthol from Japanese mint oil?

    <p>Cooling and filtration</p> Signup and view all the answers

    What centers of asymmetry does Menthol have?

    <p>Three</p> Signup and view all the answers

    Which compound can be used for the semi-synthesis of dl-menthol?

    <p>Thymol</p> Signup and view all the answers

    Which method causes the deposition of menthol crystals during isolation?

    <p>Cooling</p> Signup and view all the answers

    What reaction is associated with converting Thymol to Menthol?

    <p>Catalytic reduction</p> Signup and view all the answers

    Which type of alcohol is classified as primary?

    <p>RCH2OH</p> Signup and view all the answers

    What classification method is used for alcohols based on their carbon skeleton?

    <p>Aliphatic, Alicyclic, and Aromatic</p> Signup and view all the answers

    Which of the following is an example of a monocyclic alicyclic alcohol?

    <p>Menthol</p> Signup and view all the answers

    What type of alcohol is Nerolidol classified as?

    <p>Primary sesquiterpenoid alcohol</p> Signup and view all the answers

    Which of the following is NOT a saturated aliphatic alcohol?

    <p>Citronellol</p> Signup and view all the answers

    Which aromatic alcohol is characterized by a benzene ring with an alcohol group?

    <p>Benzyl alcohol</p> Signup and view all the answers

    What method is typically used for the isolation of alcohols from volatile oils?

    <p>Fractional distillation</p> Signup and view all the answers

    Which of the following statements regarding alcohol classification is accurate?

    <p>Alcohols can be classified both by type of alcoholic group and carbon skeleton.</p> Signup and view all the answers

    Which type of alcohol is most reactive in dehydration reactions?

    <p>Tertiary alcohols</p> Signup and view all the answers

    What is the primary purpose of esterification in the context of alcohols?

    <p>To separate different types of alcohols</p> Signup and view all the answers

    What reaction occurs with primary alcohols when treated with anhydrous calcium chloride?

    <p>Formation of crystalline derivatives</p> Signup and view all the answers

    Which type of ester does not react with tertiary alcohols?

    <p>All of the above</p> Signup and view all the answers

    In fractional distillation under reduced pressure, which property of the liquid is primarily utilized?

    <p>Boiling point</p> Signup and view all the answers

    Which type of reaction occurs when a primary alcohol is hydrated?

    <p>Addition</p> Signup and view all the answers

    What happens to secondary alcohols under more drastic dehydration conditions?

    <p>They react to form unsaturated hydrocarbons</p> Signup and view all the answers

    Which of the following statements is true regarding the reactivity of alcohols in the context of phthalic acid esters?

    <p>Primary alcohols require less drastic conditions than secondary alcohols</p> Signup and view all the answers

    What is one of the pharmacological actions of menthol?

    <p>Local anesthetic</p> Signup and view all the answers

    Which compound is primarily associated with a camphor-like odor?

    <p>d-Borneol</p> Signup and view all the answers

    What is the main constituent of pine needle oils derived from borneol?

    <p>Bornyl acetate</p> Signup and view all the answers

    How is isoborneol classified in relation to borneol?

    <p>An artifact during the preparation of borneol-rich oils</p> Signup and view all the answers

    Which method is used to isolate borneol from pine needle oil?

    <p>Fractional distillation after saponification</p> Signup and view all the answers

    What chemical reaction is used to obtain borneol from α-pinene?

    <p>Reduction</p> Signup and view all the answers

    What is the primary odor profile associated with α-terpineol?

    <p>Floral</p> Signup and view all the answers

    Which property of menthol contributes to its use in personal care products like mouthwashes and toothpastes?

    <p>Cooling sensation</p> Signup and view all the answers

    What happens to 3ry alcohols under the specified reaction conditions?

    <p>They are rapidly dehydrated.</p> Signup and view all the answers

    Which of the following methods can be used to extract acid phthalates?

    <p>Extracted with NaHCO3.</p> Signup and view all the answers

    Which alcohol type is quantitatively determined using the described processes?

    <p>Primary alcohols.</p> Signup and view all the answers

    What type of compounds are formed from the reaction of carbamic acid with primary and secondary alcohols?

    <p>Carbamates or urethanes.</p> Signup and view all the answers

    Which reaction can separate primary alcohols from secondary and tertiary alcohols?

    <p>Saponification.</p> Signup and view all the answers

    What is indicated by the formation of diphenyl urethane derivatives in the context of geraniol and nerol?

    <p>Their differing melting points.</p> Signup and view all the answers

    Which of the following statements about secondary alcohols is true?

    <p>They can form higher temperatures around 120-130°C.</p> Signup and view all the answers

    How can the hydrolysis of acid phthalates be achieved?

    <p>Through saponification with alcoholic alkalis.</p> Signup and view all the answers

    Study Notes

    Oxygenated Compounds

    • Phytochemistry Lecture 4 covers oxygenated compounds, including alcohols, phenols, aldehydes, ketones, esters, oxides, and peroxides.

    Alcohols in Volatile Oils

    • Alcohols in volatile oils are frequently found with their esters.
    • They are typically terpenoid or aromatic in nature.
    • Classification:
      • Based on the alcoholic group type: Primary (RCH₂OH), Secondary (R₂CHOH), and Tertiary (R₃COH).
      • Based on the carbon skeleton: Aliphatic (acyclic), Alicyclic, and Aromatic.
      • Further categorized into saturated, unsaturated, monoterpenoid, sesquiterpenoid, and aromatic alcohols. Specific examples of each type are included in the slides.

    Isolation of Alcohols in Volatile Oils

    • Methods of isolation: Fractional distillation under reduced pressure, Chromatography (CC, HPLC, GLC), Counter Current Extraction, Formation of crystalline derivatives (derivatization).

    Reactions of Alcohols in Volatile Oils

    • Derivatization of Terpenoid Alcohols:

      • Reactions similar to those of terpenoid hydrocarbons: Addition reactions (hydration, hydrogenation, halogenation).
      • Reactions due to the presence of the alcoholic groups: Reactivity varies by alcohol type (1°, 2°, or 3°).
      • The formed derivatives often have definite melting points used for identification or quantitative determination.
    • Dehydration Reactions: Used for 3° alcohols. 2° alcohols require harsher conditions; 1° alcohols generally do not readily dehydrate. Geraniol is an exception.

    • Calcium Chloride Additive Compounds: Used to separate 1° alcohols (e.g., geraniol) from other alcohols by forming crystalline salts.

    • Esterification:

      • Reaction speeds depend on the type of alcohol (1°, 2°, or 3°).
      • Borates, acid phthalates, and urethans (carbamates) are common esters.
      • Used to separate 1° and 2° alcohols from 3° alcohols.
      • Specific ester types, such as benzoates, react with specific alcohol types (1° and 2°).
    • Phthalic Acid Esters (Phthalates): These esters are used to identify and separate primary and secondary alcohols from tertiary ones by forming water soluble salts, and under differing conditions.

    • Carbamic Acid Esters (Carbamates/Urethanes): Used for identifying 1° and 2° alcohols. Specific derivatives have distinct melting points enabling identification.

    Acyclic Terpenoid Alcohols

    • Citronellol:

      • Source: Oil of citronella, geranium, and rose.
      • Properties: Optically active liquid with a rose-like odor.
      • Uses: Perfume, cosmetics, soaps, rose oil substitute, insecticide.
    • Geraniol & Nerol:

      • Source: Geranium, oils of neroli, and other oils.
      • Properties: Optically inactive liquids with a rose-like odor.
      • Reactions: Reactive under certain conditions (degradation), used in preparing derivatives for identification and separation.
      • Uses: Perfume, cosmetics, flavorings, and oil substitutes.
    • Linalool:

      • Source: Oils of lavender, bergamot, coriander, nutmeg.
      • Properties: Optically active liquid with a lavender-like odor, highly unstable.
      • Reactions: Easily dehydrates to monoterpene hydrocarbons. Often oxidized.
      • Uses: Perfume, cosmetics, oils substitutes, in flavorings.

    Alicyclic Terpenoid Alcohols

    • (-)-Menthol:

      • Source: Oils of peppermint and Japanese mint.
      • Properties: Crystalline, has a mint-like odor and a cooling taste, optical isomers.
      • Isolation: Isolated by cooling Japanese mint oil.
      • Semi-synthesis: Can be created through enzymatic or catalytic reduction.
      • Reactions: Shows various reactions, including oxidation, dehydrogenation, and dehydration.
      • Uses: Flavoring agent, topical anesthetic (cough drops, etc.).
    • a-Terpineol:(detailed properties and uses exist in other sections)

      • Source: Neroli, pine, camphor tree, and cajuput oil.
      • Types: Different forms depending on the source.
      • Isolation: Fractional distillation and acid phthalate preparation.
      • Uses: Perfume, soaps, flavorings.
    • Borneol & Isoborneol:

      • Source: Pine needle oils.
      • Borneol: Natural, useful for perfumes, and other preparations.
      • Isoborneol: Artifact, unstable in harsher conditions, but important in the separation process.
      • Isolation: Fractional distillation from pine needle oil, sometimes use acid phthalates.

    Aromatic Alcohols

    • Benzyl Alcohol:
      • Source: Balsam Peru, balsam Tolu, and storax oils, and in jasmine oil.
      • Properties: Used as a fixative in perfume.
      • Reactions: Forms esters used in perfumery.
    • Phenyl Ethyl Alcohol:
      • Source: Rose, Neroli.
      • Properties: Rose-like odor used in perfumes, and flavors, and other related products.

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    This quiz covers Oxygenated Compounds discussed in Phytochemistry Lecture 4, focusing on alcohols, phenols, aldehydes, and more. Learn about the classification, isolation methods, and reactions of alcohols in volatile oils.

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