Styrene → Styrene

HRID 1460880Notes

Reaction equation

HRID 1460880 reaction equation
[CH2:1]=[CH:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.[C:9]([O:16][CH:17]([CH3:19])[CH3:18])(=[O:15])/[CH:10]=[CH:11]\[C:12]([OH:14])=[O:13].[C:20]1(=[O:26])[O:25][C:23](=[O:24])[CH:22]=[CH:21]1.Cl.N1C=CC=C[CH:29]=1>O1C=CCCC1>[CH2:1]=[CH:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.[C:9]([O:16][CH:17]([CH3:19])[CH3:18])(=[O:15])/[CH:10]=[CH:11]\[C:12]([O:14][CH:23]1[CH2:22][CH2:21][CH2:29][CH2:20][O:25]1)=[O:13].[C:23]1(=[O:24])[O:25][C:20](=[O:26])[CH:21]=[CH:22]1

Participants

8

Reactant 4

HCID 7501StyreneHCID 7923Maleic AnhydrideHCID 6436106Monoisopropyl maleateHCID 10176127Pyridinium chloride

Product 3

HCID 7501StyreneHCID 7923Maleic AnhydrideHCID 67928807Isopropyl tetrahydropyranyl maleate

Reagents, catalysts & solvents 1

HCID 80803,4-dihydro-2H-pyranSolvent

Procedure

A 5 g sample of poly(styrene [50 mol %], isopropyl hydrogen maleate [32 mol %], maleic anhydride [18 mol %]) was suspended in 75 mL of 3,4-dihydro-2H-pyran and treated with 0.1 g of pyridine hydrochloride. The mixture was stirred at reflux for 18 hours, during which time a homogeneous solution was formed. After cooling to room temperature, the solution was stirred for 1 hour with crosslinked poly(dimethylaminomethylstyrene) to remove the catalyst. After filtration, the product was isolated from the filtrate by precipitation in methanol and dried to give 3 g of poly(styrene, isopropyl tetrahydropyranyl maleate, maleic anhydride). Titration of the starting material with 0.1N sodium hydroxide shows 4.32 meq/g of anhydride and acid. Titration of the product shows 2.49 meq/g of anhydride. IR analysis of the product shows absorption characteristic of anhydride (1855 and 1780 cm-1), but no absorption characteristic of carboxylic acid. Differential scanning calorimetry (DSC) of the product shows a sharp decomposition endotherm peaking at 153.9° C. (104.1 J/g) which is absent from the starting material. Thermal gravimetric analysis (TGA) shows a 13.36% weight loss centered at 154.54° C. which is not seen in the TGA of the starting material. The thermal event at 154° C. is the thermal loss of dihydropyran to form polymeric carboxylic acid groups.

Workup

  1. temperatureat reflux for 18 hours, during which time a homogeneous solution
  2. customwas formed
  3. customto remove the catalyst
  4. filtrationAfter filtration
  5. customthe product was isolated from the filtrate by precipitation in methanol
  6. customdried

Sources & evidence

ORD record
ord-b7889cdfefce4d0ea6e067900cc26bc1
Source dataset
uspto-grants-1991_12
Patent number
US05072029

Reaction notes

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