Condensation of bisphenol-A with phosgene yields which engineering thermoplastic noted for high heat resistance and impact strength?
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APolyurethane
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BPolysulphone
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CPolycarbonate
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DPolyester
Answer
Correct Answer: Polycarbonate
Explanation
Introduction / Context:Knowing the monomer pairs helps identify the polymer family and its properties. Bisphenol-A and phosgene form carbonate linkages that define a widely used clear engineering plastic.
Given Data / Assumptions:
- Bisphenol-A (diol) and phosgene (carbonyl chloride) are the reactants.
- Interfacial or melt transesterification routes may be used.
- We compare to other polymer families.
Concept / Approach:Bisphenol-A + phosgene → polycarbonate (PC), featuring carbonate linkages in the backbone. Polyurethanes arise from diisocyanate + polyol; polysulphones involve sulphone linkages; generic “polyesters” are from diols with diacids/diesters (not specifically BPA + phosgene).
Step-by-Step Solution:Map BPA + phosgene → carbonate linkages → PC.Eliminate polyurethane, polysulphone, and unspecific polyester.
Verification / Alternative check:Manufacturing routes for PC include interfacial phosgenation and phosgene-free transesterification (DPC route), both anchored to BPA.
Why Other Options Are Wrong:Chemistries do not match the listed monomer pair.
Common Pitfalls:Mixing up carbonate vs ester linkages due to similar names.
Final Answer:Polycarbonate