1,4-Difluorobenzene

1,4-Difluorobenzene

C₆H₄F₂

CAS No.:540-36-3

One often utilized fluorine-containing medication intermediary is 1,4-difluorobenzene. There are currently two main ways to prepare 1,4-difluorobenzene: either use p-phenylenediamine to prepare 1,4-difluorobenzene through Schiemann reaction in the presence of hydrochloric acid and fluoroboric acid, or use p-chloronitrobenzene as the raw material, reacting with potassium fluoride to obtain p-nitrofluorobenzene, p-nitrofluorobenzene being reduced to p-fluoroaniline, and then using Schiemann reaction to obtain 1,4-difluorobenzene. Both techniques use the Schiemann reaction, which necessitates the diazonium salt of fluoroborate be prepared, separated, and thermally broken down. Diazonium salt solids undergo a thermal breakdown reaction that is low in yield, difficult to design for continuous operation, and prone to explosions.

After bringing the reaction kettle down to -10°C, add 400g of liquid hydrogen fluoride and 1.0 mol of p-phenylenediamine. It takes ten minutes of mechanical stirring to completely dissolve the reactants. Add sodium nitrite (75.9g, 1.1mol) gradually and let it react for three hours. Once the reaction is finished, place it in a water bath to heat. The diazonium salt is fully broken down when no bubbles appear in the air output pipe.After adding the reaction solution to a designated separatory funnel, leave it alone. After separating the organic layer, 10% sodium hydroxide was added to bring it up to alkalinity. Dry the oil phase on anhydrous sodium sulfate after separating it. To achieve a white liquid with a boiling point of 88°C and a refractive index of 1.4410, distill the dried organic layer under normal pressure.

An enhanced Schiemann reaction method is used to manufacture 1,4-difluorobenzene with p-phenylenediamine as the primary raw material. The enhanced method can operate continuously and can be used with anhydrous hydrogen fluoride without requiring the diazonium salt to be separated. The following are the reaction conditions: Choose the HF-triethylamine system; the yield is 78%, the diazotization reaction time is 3 hours, and n (sodium nitrite): n (p-phenylenediamine) = 2.2.

Synonyms:

1,4-Difluorobenzene 100mg [540-36-3];1,4-Difluorobenzene, 99+% 25ML;Ontwofluorobenzene;For fluorobenzene;1.4-Difluorobe;P-DIFLUOROBENZENE;1,4-difluoro-benzen;1,4-difluroethylene

Packing, Storage, Handling and Transportation

Hexafluorobenzene should be sealed in dry place at room temperature.

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