Iodine → HCID 13535835, compound

HRID 1155482Notes

Reaction equation

HRID 1155482 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]2[C:9](=[O:10])[O:8][C:6](=[O:7])[C:5]2=[CH:11][CH:12]=1.II.S(=O)(=O)(O)O.[O-]S([O-])=O.ClCl.[Cl:26]C1C=C(C(O)=O)C(C(O)=O)=CC=1C>C1(C)C(C)=CC=CC=1.O>[Cl:26][C:3]1[C:2]([CH3:1])=[CH:12][CH:11]=[C:5]2[C:6]([O:8][C:9](=[O:10])[C:4]=12)=[O:7]

Participants

9

Reactant 6

HCID 807IodineHCID 1099SulfiteHCID 1118Sulfuric AcidHCID 24526Chlorine3×HCID 880694-Methylphthalic anhydrideHCID 20560951HCID 20560951, compound

Product 1

HCID 13535835HCID 13535835, compound

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 7237O-XyleneSolvent

Procedure

10 Grams of 4-methylphthalic anhydride, 0.1 g of iodine and 50 g of fuming sulfuric acid having the sulfuric anhydride content of 5 wt % were mixed, in which chlorine gas was blown at a feed rate of 7 ml/min with stirring. Feeding of chlorine gas was stopped when 0.062 mole of chlorine had been reacted with the anhydride. Then, the reaction mixture was poured into 250 g of water, cooled to effect precipitation. The precipitate was washed with a small amount of water and dried at 70° C. to give 9.2 g of a crude chlorinated product. Gas chromatographic analysis, conducted under the above-described conditions, revealed that the product consisted of 33.1 wt % of 5-chloro-4-methylphthalic acid, 42.8 wt % of 3-chloro isomer, 6.1 wt % of 3,5-dichloro compound, and 1.6 wt % of other compounds. Monosubstituted compounds were isolated from the crude mixture in the following manner. A mixture of 1 part of the crude product and 10 parts of xylene was heated at 90°-95° C. for 7 hours with stirring. The resulting hot mixture was then filtered to separate the mixture into a filtrate and solid mainly consisting of 5-chloro-4-methylphthalic acid. Xylene was distilled off from the filtrate and the distillation bottom was subjected to recrystallization with xylene several times, thereby obtaining substantially pure 3-chloro-4-methylphthalic anhydride in the form of colorless prismatic or pillared crystals. The 3-chloro product was found to have a melting point of 133°-135° C. The solid was added to xylene, which was refluxed to give a solution. The solution was cooled to effect precipitation. The resulting precipitate was subjected to repeated crystallization with xylene, thereby obtaining substantially pure (purity 99.9% or more by gas chromatographic analysis) 5-chloro-4-methylphthalic anhydride in the form of colorless hexahedral or thick platy crystals having a melting point of 152°-154° C. The chemical shifts, in terms of τ values, of the methyl group in proton NMR absorption spectrum of each of the monochloro products were found to be 7.42 ppm (in CDCl3).

Workup

  1. temperaturecooled
  2. customprecipitation
  3. washThe precipitate was washed with a small amount of water
  4. customdried at 70° C.
  5. customto give 9.2 g of a crude chlorinated product
  6. customMonosubstituted compounds were isolated from the crude mixture in the following manner
  7. temperaturewas heated at 90°-95° C. for 7 hours
  8. stirringwith stirring
  9. filtrationThe resulting hot mixture was then filtered
  10. customto separate the mixture into a filtrate and solid
  11. distillationXylene was distilled off from the filtrate
  12. distillationthe distillation
  13. custombottom was subjected to recrystallization with xylene several times

Sources & evidence

ORD record
ord-c4cd542e61b443e0a87d679bd73ef683
Source dataset
uspto-grants-1981_11
Patent number
US04302396

Reaction notes

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