Hydrochloric Acid → 2,4-Dichloro-5-carboxybenzenesulfinic acid
Reaction equation
S([O-])([O-])=O.[Na+].[Na+].[Cl:7][C:8]1[CH:16]=[C:15]([Cl:17])[C:14]([S:18](Cl)(=[O:20])=[O:19])=[CH:13][C:9]=1[C:10]([OH:12])=[O:11].[OH-].[Na+].Cl>O>[Cl:17][C:15]1[CH:16]=[C:8]([Cl:7])[C:9]([C:10]([OH:12])=[O:11])=[CH:13][C:14]=1[S:18]([OH:20])=[O:19]Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 25 °C
Procedure
A three liter flask equipped with a mechanical stirrer, thermometer and dropping funnel is charged with sodium sulfite (378 g,; 3.0 moles) and water (1 liter). The solution is cooled in an ice bath and treated with 2,4-dichloro-5-chlorosulfonylbenzoic acid (290 g.; 1.0 mole) and 10N sodium hydroxide (290 ml.) simultaneously in small portions over a period of 1.5 hours keeping the temperature below 20° C. and the pH of the reaction at 9. When the addition of the reagents is complete, the reaction is stirred for 3 hours at 25° C. then cooled to 10° C. and acidified with concentrated hydrochloric acid (440 ml.). The 2,4-dichloro-5-carboxybenzenesulfinic acid which precipitates is filtered, washed with ice water, then used in the next step without further purification.
Workup
- customA three liter flask equipped with a mechanical stirrer
- temperatureThe solution is cooled in an ice bath
- customthe temperature below 20° C.
- customthe pH of the reaction at 9
- additionWhen the addition of the reagents
- temperaturethen cooled to 10° C.
- customThe 2,4-dichloro-5-carboxybenzenesulfinic acid which precipitates
- filtrationis filtered
- washwashed with ice water
- customused in the next step without further purification
Sources & evidence
- ORD record
- ord-bb61811a6f2743e6924213fbc8dc8097
- Source dataset
- uspto-grants-1976_04
- Patent number
- US03953476
Reaction notes
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