Organic Chemistry: Exploring Hydrocarbons, Alcohols, and More

Posted on Nov 2, 2024 in Chemistry

Hydrocarbons

Alkanes

Alkanes, also called paraffins, are saturated hydrocarbons composed of carbon and hydrogen. They are saturated because they contain only single bonds. Saturated hydrocarbons may be linear or branched.

Alkenes and Alkynes

Alkenes and alkynes are hydrocarbons containing double (alkenes) or triple bonds (alkynes). Ethylene (ethene) is used as feedstock for polyethylene and in fruit ripening. Beta-carotene gives color to various plants and is a source of vitamin A. Acetylene (ethyne) is used as fuel and in welding torches.

Ternary Organic Compounds

Ternary organic compounds involve three elements: carbon, oxygen, and hydrogen.

Alcohols

Primary Alcohol: The hydroxyl group is attached to a primary carbon atom (e.g., propanol).
Secondary Alcohol: The hydroxyl group is attached to a secondary carbon atom (e.g., 2-propanol).
Tertiary Alcohol: The hydroxyl group is attached to a tertiary carbon atom (e.g., 2-methylpropanol).

Physical Properties of Alcohols

  • Generally, colorless liquids with a pleasant odor (methanol, ethanol, propanol) turning unpleasant with higher molecular weight.
  • The first 11 alcohols are liquids at room temperature, while higher alcohols are solids.
  • Melting point increases with the number of carbon atoms.
  • Boiling point is much higher than that of alkanes with the same number of carbon atoms due to hydrogen bonding.
  • Lower molecular weight alcohols are soluble in water; solubility decreases with increasing molecular weight (e.g., hexanol is practically insoluble).
  • Primary alcohols are less dense than secondary and tertiary alcohols.

Chemical Properties of Alcohols

  1. Combustion: Alcohols burn readily in the presence of oxygen, producing carbon dioxide, water, and heat. CH3OH + 3/2 O2 → CO2 + 2H2O
  2. Oxidation:
    a) Primary Alcohols: Oxidize to aldehydes, which can be further oxidized to carboxylic acids.
    b) Secondary Alcohols: Oxidize to ketones.
    c) Tertiary Alcohols: Resistant to oxidation.
  3. Dehydration:
    a) At 170°C: Forms alkenes.
    b) At 140°C with sulfuric acid: Forms ethers.
  4. Esterification: React with organic acids in the presence of sulfuric acid and heat to form esters.

Applications and Uses of Common Alcohols

  • Methanol: Solvent, antifreeze, and in the production of methanal (formaldehyde). Poisonous and can be fatal if ingested.
  • Ethanol: Disinfectant, solvent in varnishes, explosives, rayon manufacturing, and alcoholic beverages.

Phenols

Phenol (hydroxybenzene): Used in the plastics industry, and in the preparation of picric acid for dyes, explosives, and burn treatments.

Physical Properties of Phenols

  • Colorless liquid with a faint aromatic odor.
  • Slightly soluble in water and slightly denser than water.

Chemical Properties of Phenols

  • Can yield aldehydes and carboxylic acids upon oxidation, depending on the oxidant.

Uses of Phenol

  • Antiseptics, disinfectants, insecticides.
  • Manufacture of plastics, soaps, textiles.
  • Production of trinitroglycerin for dynamite.

Alcohol Production by Fermentation

Fermentation is the catalytic breakdown of organic compounds by enzymes produced by microorganisms, animal cells, or plant cells. Enzymes, belonging to the protein family, break down carbohydrates, fats, proteins, and acids. Ethanol is industrially produced by the fermentation of glucose using brewer’s yeast, yielding ethanol and carbon dioxide. This is called alcoholic fermentation.

Isomerism

  • Chain Isomerism: Different arrangements of the carbon chain.
  • Position Isomerism: Different positions of the functional group.
  • Functional Isomerism: Different functional groups.
  • Geometric Isomerism (Stereoisomerism): Different spatial arrangements of atoms.

Chemical Properties of Hydrocarbons

Alkanes

  • Combustion: Burn in the presence of oxygen, producing carbon dioxide, water, and a blue flame.
  • Halogenation: Hydrogen atoms can be replaced by chlorine or bromine atoms.

Alkenes and Alkynes

  • Combustion: Readily combustible.
  • Addition Reactions:
    a) Hydrogenation: Addition of hydrogen to form saturated compounds, often using platinum as a catalyst.
    b) Halogenation: Used to identify double or triple bonds.
    c) Hydration: Addition of water to form alcohols, following Markovnikov’s rule.
    d) Hydrogenation of Alkynes: Forms a solid, insoluble yellow or brown precipitate.

Physical Properties of Hydrocarbons

Hydrocarbons are nonpolar molecules with weak London dispersion forces. They exhibit various states of aggregation depending on their molecular weight.

Properties of Benzene

: * A room temperature is an oily liquid, flammable, penetrating odor. * Pqtroquimica industry for disinfectants, medicamnecyos, plsticos, detergents, dyes, others. * Different chemical properties of the aromatic hydrocarbons .* Viewed unlike alkenes, substitution reactions occur. Cracking: FROM FUEL OIL TO NAFTA: Distillation consists of hydrocarbons, each day more gasoline is needed, how to increase the yield of oil. This is the catalytic cracking or disintegration uan pressure between 2 to 3 atm. Materials are used white solid, refractory and divided. The new mixture is distilled in a tower. You get: * naphtha steam quality and gaseous hydrocarbons, by the head .* superio or light catalytic gasoil, diesel po .* ctalitico medium heavy, the bottom of the queue, * carbon residue called petroleum coke covers the catalysts. ALDEHYDES AND KETONES: aldehydes and ketones are among the chemical industry .. in naturalesa substances necessary for living systems are aldehydes and ketones. In the chemically synthesized quantities are used as solvents or as feedstock. He made tons of formaldehyde sive insulating materials. FEATURES: * precent of aldehydes and ketones as the carbonyl functional group ladehidos .* the functional group is always a primary carbon atom and together with a hydrogen atom in ketones .* carbonyl group is attached to an atom carbonne secondary.