Author Topic: Ever lasting quest for 4-Fluorobenzaldehyde  (Read 129 times)

T-cowboy

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Ever lasting quest for 4-Fluorobenzaldehyde
« on: March 19, 2013, 07:33:00 PM »
As mentioned above.

Tried everything, not making it. look at the synth. (tetrakis, expensive) even contacted our beloved china mainland. but no luck.


Any input or just pinch me in the right direction would be greated with a kiss on the hand. No mean to spoonfeed.


Thanks you guys

Wizard X

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Re: Ever lasting quest for 4-Fluorobenzaldehyde
« Reply #1 on: March 19, 2013, 11:38:48 PM »
4-fluorobenzaldehyde from 4-chlorobenzaldehyde. US Patent 6166242; posted Rhodium archive.

140 g (1 mol) of 4-chlorobenzaldehyde, 58 g (1 mol) of potassium fluoride, 5 g of nitrobenzene and 7.98 g of tetrakis(diethylamino)phosphonium bromide  (phase transfer catalyst) are placed in a 500 ml four-neck flask fitted with thermometer, anchor stirrer and reflux condenser with bubble counter. The mixture is subsequently heated while stirring to 190°C. and allowed to react for 20 hours. After the reaction is complete, the reaction mixture is allowed to cool, dissolved in chlorobenzene, insoluble constituents are filtered off and the product (4-fluorobenzaldehyde) is purified by fractional distillation under reduced pressure. Yield 77%, with a selectivity of 93%.


A process which can afford a large quantity of 4-fluorobenzaldehyde was developed from halogen-exchange of 4-chlorobenzaldehyde with potassium fluoride in aromatic hydrocarbon solvents in the presence of tetraphenylphosphonium bromide plus polyethylene glycol dimethyl ether. The features of the reaction are discussed.  http://www.sciencedirect.com/science/article/pii/S0022113900839469

Use a different phase transfer catalyst.



Other Refs: http://www.chemada.com/files/626c7b55f0909d7f4c5c640a1e6c5824.pdf  | http://www.freepatentsonline.com/6455739.html | http://www.freepatentsonline.com/5138099.html
Albert Einstein - "Great ideas often receive violent opposition from mediocre minds."

Wizard X

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Re: Ever lasting quest for 4-Fluorobenzaldehyde
« Reply #2 on: March 20, 2013, 01:21:36 AM »
Alternatively, Diazotization is another synthesis route.

Aniline and its ring-substituted derivatives react with nitrous acid to form diazonium salts. Through these intermediates, aniline can be conveniently converted to -OH, -CN, or a halide via Sandmeyer reactions.  http://en.wikipedia.org/wiki/Aniline#Diazotization
Albert Einstein - "Great ideas often receive violent opposition from mediocre minds."

fractal

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Re: Ever lasting quest for 4-Fluorobenzaldehyde
« Reply #3 on: March 25, 2013, 09:57:54 AM »
You can find it in china easily still.

T-cowboy

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Re: Ever lasting quest for 4-Fluorobenzaldehyde
« Reply #4 on: March 25, 2013, 02:32:41 PM »
would rather avoid that route, have no experience doing bussines with them.