(Hive Bee)
11-17-02 16:46
No 380478
      p-F-benzaldehyde from p-Cl-benzaldehyde
(Rated as: excellent)

Preparation of 4-fluorobenzaldehyde From 4-chlorobenzaldehyde

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 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%

Selectivity: 93%

Benzaldehyde content: 0.01%

See also:
../rhodium/chemistry /fluoroamphetamine.html

Reference: Patent US6166242 - Method for producing compounds containing fluorine, in particular fluorobenzaldhydes and fluorobenzonitriles

"Turn on, Tune in and Drop Out"
(Chief Bee)
11-17-02 19:45
No 380527
      PTC Arylfluorodehalogenation  Bookmark   

Oh, what a very nice and useful reaction - I have already added it to the fluoroamphetamine document above.
(Hive Bee)
12-15-02 19:03
No 389702
(Rated as: excellent)

Here's a preparation of p-chlorobenzaldehyde that can be later converted into p-fluorobenzaldehyde, as described above by pHarmacist.


A 500-mL 2-necked, RB flask is provided with an air-cooled reflux condenser, 2 cm inside diameter and filled for a length of 60 cm with 56 mm glass pearls or rings (Note 1). Chlorine is to be introduced by means of a 4-mm glass tube, inserted through a cork in a neck of the flask, extending close to the bottom of the flask and provided with a small bulb with fine perforations to break up the gas stream into small bubbles. The large quantities of hydrogen chloride formed can be disposed of by means of a gas absorption trap.
Into the tared flask are placed 126.5g (1 mole) of p-chlorotoluene (Org. Syn. Coll. Vol. I, 1941, 170) and 3.8g of phosphorus pentachloride. The flask is heated in a bath kept at 160170C (Note 2), and while illuminated with direct sunlight or with an unfrosted 100W tungsten lamp a rapid stream of chlorine is introduced directly from a cylinder until the gain in weight is 5566 (Note 3).
The pale yellow or yellow-green product is then transferred to a 4-L wide-mouthed bottle containing 400mL of concentrated sulfuric acid, and stirred vigorously (hood) for five hours (Note 4). The viscous mixture is then transferred to a separatory funnel and allowed to stand overnight, after which the lower layer (Note 5) is run slowly, with stirring, into a 3L beaker three-quarters filled with cracked ice. The cream-colored solid obtained when the ice has melted is filtered by suction, washed with water, pressed dry on the funnel, and divided into three equal parts. Each portion is dissolved in a minimum of ether, and the ether solution is repeatedly shaken with 2% sodium hydroxide solution until acidification of the washings gives no precipitate of p-chlorobenzoic acid (Note 6).
After removal of the ether by distillation on a steam bath, the residue is distilled under diminished pressure from a Claisen flask. The yield of p-chlorobenzaldehyde distilling at 108111C/25 mmHg and melting at 4647C is 7684g (5460% of the theoretical amount).


1.) The glass packing reduces the tendency of the stream of hydrogen chloride to carry away p-chlorotoluene as a spray.
If only one run is to be made, good-quality corks are satisfactory. If several runs are made, it is recommended that the corks be impregnated with sodium silicate solution to prevent excessive corrosion by the hydrogen chloride and chlorine.

2.) The bath contains either oil or graphite.

3.) The time required was 4.5 hours. In a larger run by the submitter, in which 750g of p-chlorotoluene and 23g of phosphorus pentachloride were used, the time required for a gain in weight of 330360g was 6-10 hours.

4.) Vigorous stirring is necessary to prevent undue foaming. Most of the hydrogen chloride is evolved early in stirring.

5.) The waxy upper layer is discarded.

6.) The yield of p-chlorobenzoic acid is about 20g. From the larger runs, starting with 750g of p-chlorotoluene, the yield of acid averaged 260 g.

Organic Syntheses, CV 2, 133

I'm dreaming of the white crystals.
(Hive Bee)
12-20-02 15:01
No 391013
      Thank You demorol  Bookmark   

Your post was the missing puzzle-piece, thanks to that I could synthesize pre-cursor esentiall for the synthesis of 4-fluoroamphetamine and oh boy whatta amazing compound. Thanks to Rodium for dosage advice. Whatta teamwork, this is what Hive is all about!

Thank You guys!

"Turn on, Tune in and Drop Out"
(Hive Bee)
12-27-02 04:19
No 393169
      This might also be a possibility  Bookmark   

First: Post 393163 (pHarmacist: "4-NH2-benzaldehyde from p-nitrotoluene", General Discourse)

Then something simillar to this:

Of course, by no means better than none of the above described, but still a possibility.

"Turn on, Tune in and Drop Out"
(Hive Bee)
02-07-03 17:31
No 405312
      4-fluoroamphetamine experiences?  Bookmark   

4-fluoroamphetamine and oh boy whatta amazing compound.

Hey pHarmacist- There's not a lot of first hand experiences with 4-fluoroamphetamine lying around. Would you be willing to mention a bit about it's effects, dosages and what-not? SWIM has access to some 4-fluorobenzaldehyde and is wondering if it should be considered for a project.


(Hive Addict)
02-07-03 18:03
No 405320
(Rated as: good idea!)

How about me ingesting it this weekend or next and writing a post in "real-time", while on it? That would be moust accurate way to describe the psych. effects, wouldn't you agree?

But I'll have to tune in tongue

Accept No Imitations, There Can Only Bee One;
(Hive Bee)
02-07-03 21:43
No 405376
      !  Bookmark   

How about me ingesting it this weekend or next and writing a post in "real-time", while on it? That would be moust accurate way to describe the psych. effects, wouldn't you agree?

I actually wanted to do something similar when I planned my first mescaline experience. But when the mescaline was starting to work, I stopped it at once. The substance was too intense "to waste my time on silly writings nobody would understand afterwards". So I swapped the pen for a walk in the city and several hours of wonderfully moving colours. And after all, the first couple of hours, I wasn't able to write properly at all. It was too stimulating, became mad when I sat still.

Abusus non tollit usum
(Hive Bee)
02-08-03 19:45
No 405660
      Sounds good!  Bookmark   

How about me ingesting it this weekend or next and writing a post in "real-time", while on it?

Sounds good to me! laugh


(Hive Addict)
02-09-03 15:37
No 405947
      GC_MS  Bookmark   

Yeah, but that was your _first_ M experience. I have been on 4-fluoroamphetamine several times and I'm by now familiar with the effects so I can afford to waste it in front of the screen wink

Accept No Imitations, There Can Only Bee One;
(Hive Addict)
03-01-03 18:30
No 412812
      p-CHLOROTOLUENE  Bookmark   

p-Me*C6H4*NH2 ---NaNO2/HCl---> p-Me*C6H4*N+N}Cl- ---CuCl/HCl---> p-Me*C6H4Cl

Is ther any interest in this? Should I type in the detailed lab-procedure from Vogel's fifth edition?

Yep, I've finally got it!!! laugh

Ref: Vogel's textbook of practical org. Chem. 5:th edition page 931, experiment 6.71

Accept No Imitations, There Can Only Bee One;