Interpretation: The mechanism for branching in free radical polymerisation of styrene is to be shown and the type of aliphatic hydrogen which is most likely to be abstracted is to be explained.
Concept Introduction: Free radical polymerisation is the polymerisation in which
To determine: The mechanism of the given reaction; also the type of hydrogen which is most likely to be abstracted in the given reaction.
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Chapter 26 Solutions
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- Chain branching is not as common with anionic polymerization as it is with free-radical polymerization and cationic polymerization. Propose a mechanism for chain branching in the polymerization of acrylonitrile.arrow_forwardRadical polymerization of styrene gives a linear polymer. Radical polymerization of a mixture of styrene and 1,4-divinylbenzene gives a cross-linked network polymer of the type shown in Figure 29.1. Show by drawing structural formulas how incorporation of a few percent of 1,4-divinylbenzene in the polymerization mixture gives a cross-linked polymer.arrow_forwardProvide the mechanism for the step-growth polymerization of citric acid and ethylene glycol to form poly (ethylene glycol)-citrate. Show all steps.arrow_forward
- Describe the polymerization of 2,2-dimethyloxirane by an anionic mechanism.arrow_forwardGive a mechanism, showing chain branching during the free-radical polymerization of styrene. There are two types of aliphatic hydrogens in the polystyrene chain. Which type is more likely to be abstracted?arrow_forwardFor the cationic polymerization of ethyl vinyl ether initiated with a water/aluminum chloride initiator system shown below, give the mechanisms and products for the following reactions. n H₂O AICI 3 a) initiation (include equilibrium for initiator creation), b) propagation, and c) termination by initiator recombination.arrow_forward
- Below are the reaction steps in a certain polymerization process, 22. which may occur by either an uncatalyzed or an acid-catalyzed pathway. 0–H R-C-o–H k1 + HA R-C+ A- k2 0–H Group 1 0–H 0–H k3 R-ċ+ A- + R'+o-H R—С—0—Н k4 0–H R-ó+ A- Group 2 H 0–H R–Ċ–0–H k5 R-C-0–R' + H-0 + НА A- Group 3 H Write a balanced chemical reaction for the overall process. RCOOH + HA + RCOOH2+ + A- + R'OH + RC(OH)2(R'OH)+ ® RCOOH2+ + RC(OH)2(R'OH)+ + RCOOR' + H2O + HA. RCOOH + R'OH 2 RCOOR' RCOOH + R'OH E RCOOR' + H20 RCOOH + HA 2 RCOOH2+ + A- RCOOH + R'OH + HA E RCOOR' + H2O + HAarrow_forward16 The molecular weight of polymer when styrene is polymerized in benzene is 400,000. With all other conditions the same, addition of 4.23 mg/L of n-butyl mercaptan de- creases the molecular weight to 85,000. What concentration (mg/L) of n-butyl mer- captan will give a molecular weight of 50,000 (other conditions remaining the same) ? [Ans. 8 mg L-l]arrow_forward• What do you mean by auto-acceleration? • List down the factors that affect the cationic polymerization. Fill in: Unlike free radical polymerization, the termination in cationic polymerization occurs by -----. • In cationic polymerization, Dp increases with ---- in polarity, ---- in T and ---- in acidity.arrow_forward
- Draw the structure of the polymer that results from anionic polymerization of p-trichloromethylstyrene (CCl3C6H4CH =CH2) using ethylene oxide as the electrophile to terminate the chain.arrow_forwardChain branching occurs in cationic polymerization much as it does in free-radical polymerization. Propose a mechanism to show how branching occurs in the cationic polymerization of styrene. Suggest why isobutylene might be a better monomer for cationic polymerization than styrene.arrow_forwardWhen propylene oxide is polymerized by addition of BF3/H20 catalyst to a solution of monomer, a low molar-mass polyether is formed. However, if the monomer is added slowly to a solution of the catalyst, a polymer with significantly higher molecular weight is isolated. Explain the mechanistic aspects of the polymerization that leads to these results.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning