Condensation of formaldehyde with phenol in the presence of dilute H2SO4 yields________________?
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Answer: D. Bakelite
Explanation
Phenol and formaldehyde undergo acid-catalyzed condensation polymerization to form a rigid thermosetting network. Cross-linking reactions between formaldehyde and phenol molecules yield the synthetic polymer known as Bakelite. Dilute sulfuric acid catalyzes the initial addition and subsequent condensation steps required to build Bakelite. Bakelite was one of the earliest synthetic plastics created from cheap and accessible petrochemical precursors. Thermosetting polymers form permanent three-dimensional cross-linked networks that cannot be remelted easily. Acid catalysts protonate formaldehyde to enhance its electrophilic attack on activated aromatic phenol rings.
Bakelite revolutionized electrical engineering due to its exceptional insulating properties and thermal stability. Vintage appliance housings and electrical switches were commonly manufactured from molded phenol-formaldehyde resins. Polymer chemistry courses study Bakelite as a prime historical example of early cross-linked thermosets. Nylon 66 is produced from diamines and dicarboxylic acids rather than from phenol and formaldehyde. Urotropine is formed by reacting formaldehyde with ammonia rather than through phenol condensation. Aniline formaldehyde plastics require aniline instead of phenol as the primary aromatic reactant.
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