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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    Description

    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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