Polycondensation of a saturated dicarboxylic acid with a polyhydric alcohol typically produces which class of resin?

Difficulty: Easy

Correct Answer: Alkyd resin

Explanation:


Introduction / Context:
Alkyds are workhorse coating resins. Recognising their synthetic origin helps distinguish them from epoxies, phenolics, and polyamides which arise from different monomer families and cure chemistries.



Given Data / Assumptions:

  • Saturated dicarboxylic acid (or anhydride) reacts with a polyhydric alcohol (polyol).
  • We consider classical resin manufacture used in coatings.



Concept / Approach:
Alkyd resins are polyesters modified with fatty acids or oils, formed by condensation of diacids/anhydrides (e.g., phthalic anhydride) with polyols (e.g., glycerol, pentaerythritol). Epoxies derive from epoxide monomers; polyamides from diamine + diacid; phenolics from phenol + formaldehyde. Thus the described reaction is characteristic of alkyd formation.



Step-by-Step Solution:
Match monomers (diacid + polyol) to polyester/alkyd chemistry.Identify coatings context → alkyd resin.Eliminate epoxy, polyamide, and phenolic which use different monomers.



Verification / Alternative check:
Coatings texts define alkyds as oil-modified polyesters made by polycondensation of polyols and polybasic acids.



Why Other Options Are Wrong:
Monomer sets and mechanisms do not match the given description.



Common Pitfalls:
Confusing generic “polyester” with the more specific, oil-modified “alkyd” used in paints.



Final Answer:
Alkyd resin

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