Hydrochloric Acid → Phenylglyoxylic Acid

HRID 128884Notes

Reaction equation

HRID 128884 reaction equation
[CH3:1][C:2]([C:4]1[CH:5]=[CH:6][C:7](O)=[CH:8][CH:9]=1)=[O:3].Cl.N([O-])=[O:13].[Na+].[OH2:16]>>[OH:16][C:1](=[O:13])[C:2]([C:4]1[CH:5]=[CH:6][CH:7]=[CH:8][CH:9]=1)=[O:3]

Participants

5

Reactant 4

HCID 313Hydrochloric AcidHCID 962WaterHCID 74694'-HydroxyacetophenoneHCID 23668193Sodium Nitrite2×

Product 1

HCID 11915Phenylglyoxylic AcidYield 83.3%

Conditions

Temperature
55 °C

Procedure

A two liter five-neck round-bottom flask is charged with 4-hydroxyacetophenone (4-HAP) (100 g, 0.74 mol) followed by the addition of 286 g water and 31% of aqueous HCl (383.3 g, 3.31 mole). The reaction mixture is stirred and heated to 55° C. Aqueous solution of 42% NaNO2 (286 g, 1.62 mol) is added to the generator at a rate of 2.9 grams per minute (100 minute addition). The temperature is maintained at 55° C. After NaNO2 addition is complete, the reaction is continued for another thirty minutes to remove the remaining NOCl. Analysis of the reaction mixture indicates the presence of 9.89 weight percent HPGO (hydroxyphenyl glyoxal) which corresponds to a HPGO yield of 83.3%. The reaction mixture is then cooled to 40° C. and then hydroxylamine free base (112 g, 0.882 mol) is added over a period of ninety minutes. After the addition is complete, the reaction mixture is cooled to 5° C. Filtration affords a solid (114 g). Analysis indicates that the solid contains 14% H2O, 76% HINAP (4-hydroxyisonitrosoacetophenone), 3% HPGO, 2% 4-HAP and 4% unknown. This corresponds to isolated HINAP to be 72%.

Workup

  1. temperatureThe temperature is maintained at 55° C
  2. waitthe reaction is continued for another thirty minutes
  3. customto remove the remaining NOCl

Sources & evidence

ORD record
ord-662a72032cc54ea3b47265467da1aba1
Source dataset
uspto-grants-1995_11
Patent number
US05464941

Reaction notes

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