Benzene → Isoprene

HRID 1981479Notes

Reaction equation

HRID 1981479 reaction equation
[CH:1]([Li])([CH2:3][CH3:4])[CH3:2].[CH:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1>>[CH2:4]=[CH:3][C:1](=[CH2:2])[CH3:6].[CH2:1]=[CH:2][C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.[CH2:4]=[CH:3][C:1](=[CH2:2])[CH3:6]

Participants

4

Reactant 2

HCID 241BenzeneHCID 178418400CID 53628100

Product 2

HCID 6557IsopreneHCID 1599892-Methylbuta-1,3-diene;styrene

Procedure

Styrene-isoprene block copolymers were synthesized by a two-stage process. In the first stage, living poly(styrene) was synthesized to initiation with sec-butyl lithium in benzene at an initiator level calculated to yield a 50,000, Mn, "living" polystyryl anion. The polymerization was carried out at 0° C. for 30 minutes after which time the reaction mixture was held at ambient temperature for 1 hour. The solution of living polymer was then split and isoprene was added to each fraction. In the first instance, an amount of isoprene sufficient to yield an isoprene block segment Mn, about 70,000, was added; in the second a larger amount of isoprene sufficient to yield an isoprene block segment of 100,000 Mn was added. In each instance the polymerization was carried out for about 2 hours at 0° C. followed by 19 hours at ambient temperature.

Workup

  1. customto yield a 50,000, Mn, "
  2. waitafter which time the reaction mixture was held at ambient temperature for 1 hour
  3. customThe solution of living polymer was then split
  4. additionisoprene was added to each fraction

Sources & evidence

ORD record
ord-68f05043ee0044a392b4ec8c86988c4a
Source dataset
uspto-grants-1986_06
Patent number
US04592989

Reaction notes

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