Author Topic: Benzaldehyde Synthesis - Douchermann  (Read 8187 times)

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Offline Vesp

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Benzaldehyde Synthesis - Douchermann
« on: August 14, 2009, 08:01:14 PM »
Benzaldehyde is a useful chemical in many pharmaceutical syntheses. A great it example is it's use to prepare mandelic acid, or cinnamic acid. It is also used as an artificial flavor, specifically almonds, or bitter almonds. It has a very sweet smell, not unlike nitroaromatics. Pure benzaldehyde is a clear, colorless liquid. It can be prepared by the sommelet reaction of benzyl chloride, or by the hydrolysis of benzal chloride.

Into a 1000ml flask, add 45g of hexamine. Prepare either a 60% ethanol solution by mixing 80ml of ethanol in 55ml of distilled water, or a 50% acetic acid solution by mixing 80ml glacial acetic acid with 80ml of distilled water. Swirl the flask at least enough to dissolve all visible solids - it doesn't have to become a completely clear solution, you just don't want a cake of hexamine at the bottom. Add 35ml of benzyl chloride to the flask and fit the reflux column to the flask. If you used ethanol, you can use a water bath, otherwise, use an oil bath to heat it to reflux and hold it there for about two hours. Prepare a ~10% solution of hydrochloric acid by mixing 20ml of 31.45% with 40ml of distilled water, or 30ml of 20% with 30ml of distilled water. After the materials in the flask have refluxed for two hours, add the above solution of hydrochloric acid to it and continue refluxing for at least 15-20min. After this, remove the flask from the bath and let it cool to room temp. You should see two layers, the bottom layer is usually a light orange and the top layer can be yellow to orange. The top layer is your benzaldehyde.

Set the flask up for simple distillation and begin heating it on an oil bath.  You will now be steam distilling the benzaldehyde from the reaction mixture/by products.  After many tests, I have found this to be the most efficient (and easiest method) to obtain the benzaldehyde.  If you used ethanol, collect the first fraction all the way up to ~98C.  Now, collect everything else distilling over (whether you used ethanol or acetic acid) until the distillate is running out is mostly clear and benzaldehyde free.  You may need to add more water to the distillation flask to aid in the steam distillation.  

If you used ethanol, take the first fraction you collected and add it to a 500ml separatory funnel.  Dilute it with about the same volume of distilled water and shake.  Let the layers separate and drain the bottom (aqueous) layer.  Add the rest of the distillate you collected (with a very obvious difference in layers) and dilute with enough water to fill the funnel up.  Drain off the lower (aqueous) layer, saving the benzaldehyde.  If you used ethanol, wash the benzaldehyde a few times with plain distilled water.  Be conservative on the water you use though, because benzaldehye is a little soluble in pure water.  If you used acetic acid, you must neutralize the benzaldehyde by washing it a few times with dilute sodium (bi)carbonate solution and distilled water.  Clearly, it is much more beneficial to use the ethanol solution as opposed to the acetic acid solution.  Once the benzaldehyde has been washed/neutralized, dry it with magnesium sulfate. It should be a clear yellow to clear orange liquid now. Distill the benzaldehyde under reduced pressure to minimize decomposition. Use a monograph to predict the boiling point of the pure benzaldehyde. You can also distill it under atmospheric pressure, but expect slight decomposition. Collect the portion coming over between 178-180C. Theoretical yield is 29.4g. Last time I attempted this, I obtained ~22g which is about a 75% yield; 70% yields are standard for this procedure.

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Offline SweetJesus

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #1 on: June 11, 2015, 04:42:00 AM »
Cant you just get almomd extract from the store? I know years ago when I wanted to learn  chemistry i had picked up some and besides getting a few odds and ends to start i didnt get any further. Is it not useable or is it not made of beneldzahyde?

Offline Vesp

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #2 on: June 11, 2015, 04:48:53 AM »
Not at the quantity and quality.
Although now manganese persulfate with toluene is the way to go.
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Offline Burgi-Dunit-Again

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #3 on: June 11, 2015, 04:33:05 PM »
I had good success with cinnamaldehyde retro-aldol. Cassia oil is very cheap and easy to obtain in large quantities. No need to purify the cinnamaldehyde even. Other than that all you need is baking soda :)

Offline Vesp

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #4 on: June 11, 2015, 05:36:37 PM »
Ah, a million different ways.
Would be a fun book to write - like a reverse tell your own story book.

"if you want your benzaldehyde to come from toluene, go to page 102, if you want your benzaldehyde to come from cinnamaldehyde, go to page 110, if you want it to come from benzyl alcohol, etc..."
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Offline SweetJesus

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #5 on: June 12, 2015, 10:18:43 PM »
The fact that you can go so many ways to make the same thing, and mixing molecules makes learning chemistry sound pretty fun. Too bad im in the same spot as years ago and dont have the time to learn it properly and too proud and a bit of lack of trust to ask for a spoon feeding lol. Maybe one day.

Offline ricky

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #6 on: March 12, 2016, 09:20:43 PM »
Seems it has also been identified as the main product in a heat-assisted Fenton reaction with mandelic acid...

http://sci-hub.io/http://www.tandfonline.com/doi/abs/10.1080/10643380500326564

It also lists phenol and hydroquinone, among others.

Offline d00d00d00

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #7 on: March 20, 2016, 09:37:43 PM »
I don't even think b-dehyde is illegal in the USA, just some sources have been harassed by DEA.  It's such a commonly used compound sold under so many different names from so many different places, but I can definitely see the need for total synthesis of it.  Hell, buying bulk Toluene raises more red flags usually because it is banned in many places due to solvent inhalant abuse.  Wow, yes, people do huff Toluene apparently....

Not knocking anything, this is very useful info, but so is the fact that benzaldehyde is definitely not illegal, just some retailers have been harassed.
I am not a chemist, just a persistent idiot.

Offline eesakiwi

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #8 on: March 21, 2016, 08:24:37 AM »
Sometimes when I fill up the car with gas, it reeks of Tolulene, and sometimes it doesn't.
It makes me wonder what actually is in our fuel.

Side note, somewhere in Aussie they realised they were loosing fuel tax $$, then relised Tolulene sales in bulk had jumped 1000%, then connected the two.

Online Tsathoggua

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #9 on: March 22, 2016, 02:47:13 PM »
Inhalant abuse, for ABuse it always is, barring a very few, cleaner, safer compounds like nitrous oxide, diethyl ether (mmmm, yum, toady loves the scent and flavour of EtOEt :D), xenon, and one could conceivably  lump in those sorts of anaesthetic polyfluorinated ethers used in surgical anaesthesia.

Sevofluorane felt pretty damn good, a far more powerful general anaesthetic agent than ether of course, so if not in a surgical context, then keeping doses small and breathing carefully so as not to simply knock oneself out cold, the dissociative effects are much more pronounced than is produced with even pretty large quantities of inhaled diethyl ether or diisopropyl ether, can't really compare it too easily with sevofluorane if the dose of ether be taken via the oral route, as of course, its probably a pretty rotten idea to go drinking the stuff :P

But in larger concentrations, such as induction in anesthesia, breathed from a mask with an oxygen supply, its really fast acting, managed to count a total of 7 breaths before blacking out.
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Offline ricky

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #10 on: March 23, 2016, 08:17:57 PM »
yeah i don't huff ether to get high, i just like the way it smells :v

mmmm, the flavour

Offline Zippy

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #11 on: March 23, 2016, 08:39:35 PM »
I like a nice ether buzz in the afternoon.

Online Tsathoggua

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #12 on: March 27, 2016, 02:09:42 PM »
Time to share this one methinks, before its ingredients become so old as to cease availability in some cases. I came up with a cocktail of sorts, based on a mixture of vodka, diethyl ether (1/3rd to 1/4 vodka, use good  stuff, ,and inhibitor-free, fresh, clean peroxide free ether, about a third of a long glass of that mixture, float a layer of mixed care+ brand codeine linctus (the sugar free orange one doesn't taste any good), this adds a faint tang of the chloroform this brand uses as a preservative) and tesco brand lime soda equal parts, ideally layering the two mixtures, and then float a little measuring cup of neat ether on top, ala jagerbomb.

Never had so wide an audience as to get a formal name, but, I propose 'manhattan...project', as a nod to the race for the atomic bomb, and manhattan cocktail. :D

Ether belches do tend to come back on one though, ala chloral hydrate, or chlorbutol. And its both longer acting and  more potent orally. So watch it, that recipe is decently drinkable, but it packs a punch that needs to be either experienced or witnessed first hand to be believed.
« Last Edit: March 27, 2016, 02:12:23 PM by Tsathoggua »
Nomen mihi Legio est, quia multi sumus

I'm hyperbolic, hypergolic, viral, chiral. So motherfucking twisted my laevo is on the right side.

Offline overunity33

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #13 on: March 27, 2016, 11:26:38 PM »
Time to share this one methinks, before its ingredients become so old as to cease availability in some cases. I came up with a cocktail of sorts, based on a mixture of vodka, diethyl ether (1/3rd to 1/4 vodka, use good  stuff, ,and inhibitor-free, fresh, clean peroxide free ether, about a third of a long glass of that mixture, float a layer of mixed care+ brand codeine linctus (the sugar free orange one doesn't taste any good), this adds a faint tang of the chloroform this brand uses as a preservative) and tesco brand lime soda equal parts, ideally layering the two mixtures, and then float a little measuring cup of neat ether on top, ala jagerbomb.

Never had so wide an audience as to get a formal name, but, I propose 'manhattan...project', as a nod to the race for the atomic bomb, and manhattan cocktail. :D

Ether belches do tend to come back on one though, ala chloral hydrate, or chlorbutol. And its both longer acting and  more potent orally. So watch it, that recipe is decently drinkable, but it packs a punch that needs to be either experienced or witnessed first hand to be believed.

Does the ethanol prevent any ether toxicity? How are the effects of drinking ether? I always wondered because it was drunk historically.

Online Tsathoggua

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #14 on: March 27, 2016, 11:31:21 PM »
Toxicity?  IMO its possibly less toxic than ethanol itself, because it cannot form a nasty aldehyde metabolite like acetaldehyde, formaldehyde in MeOH poisonings etc.

If not consumed with ethanol, there  is no hangover, pounding head, dehydration etc..
Oral lasts longer than inhaled, quite potent, very pleasant,, dissociative anaesthetic type effect reminiscent of nitrous, Got a kick like the fucking well proverbial though.
Nomen mihi Legio est, quia multi sumus

I'm hyperbolic, hypergolic, viral, chiral. So motherfucking twisted my laevo is on the right side.

Offline Halogen

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #15 on: March 17, 2017, 12:20:34 AM »
what about benzyl bromide as a sommelet reaction precursor? i know it's theoreticaly possible, but what about practice? ever tried it instead of benzyl chloride?
« Last Edit: March 17, 2017, 12:23:20 AM by Halogen »
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Offline byko3y

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #16 on: March 17, 2017, 02:12:37 AM »
There's a lot of routes to convert alkyl halide to aldehyde. In fact, first step of kornblum oxidation is formation of alkyl halide form alcohol.
Hass-Bender reaction[1],  the Sommelet reaction[2],  the Krohnke reaction[3],  the Kornblum reaction[4],  the Masaki photooxidation[5],  and oxidations using NaOCl[6],  MnO2[7], KNO3[8], DMSO[9],  Pyridine N-Oxide in the presence of Ag2O[10], and transition metal complexes[11],  green oxidation of benzyl halides with V2O5-H2O2 [12] .
1. (a) Hass, H. B.; Bender, M. L. The reaction of benzyl halides with the sodium salt of 2-nitropropane: A general synthesis of substituted benzaldehydes. J. Am. Chem. Soc. 1949, 71, 1767–1769; (b) Klanderman, B. H. Aldehyde synthesis: A study of the preparation of 9,10-anthracene-dicarbox aldehyde and other aromatic dialdehydes. J. Org. Chem. 1966, 31, 2618–2620; (c) Klein, T. A.; Schkeryantz, M. S. Tandem Hass–Bender-Henry reaction for the synthesis of dimethylnitro alcohols from benzylic halides. Tetrahedron Lett. 2005, 46, 4535–4538.
2. Larock, R. C. Comprehensive Organic Transformation; John Wiley: New York, 1999; vol. 2.
3. Nishimura, T.; Onoue, T.; Ohe, K.; Uemura, S. Palladium(II)-catalyzed oxidation of alcohols to aldehydes and ketones by molecular oxygen. J. Org. Chem. 1999, 64, 6750–6754.
4. Kornblum, N.; Jones, W. J.; Anderson, G. J. A new and selective method of oxidation: The conversion of alkyl halides and alkyl tosylates to aldehydes. J. Am.. Chem. Soc.
1959, 81, 4113–4114.
5. Akichika, I.; Tomohiro, K.; Shinji, I.; Masaki, Y. Photooxidation of arylmethyl bromides with mesoporous silica FSM-16. Org. Lett. 2000, 16, 2455–2457.
6. Khurana, J. M.; Sahoo, P. K.; Titue, S. S. Ultrasound assisted oxidation of benzylic halides with sodium hypochlorite. Synth. Commun. 1990, 20, 1357–1361. 18 P.
7. (a) Goswami, S.; Jana, S.; Dey, S. A simple and convenient manganese dioxide oxidation of benzyl halides to aromatic aldehydes under neutral condition. ChemInform 2006, 36, 28–31; (b) Goswami, S.; Jana, S.; Dey, S.; Adak, A. K. A simple and convenient manganese dioxide oxidation of benzyl halides to aromatic aldehydes under neutral condition. Chem. Lett. 2005, 34(2), 194–195.
8. Liu, Q. F.; Lu, M.; Sun, F.; Li, J.; Zhao, Y. B. Oxidation of benzyl halides to aldehydes and ketones with potassium nitrate catalyzed by phase-transfer catalyst in aqueous media. Synth. Commun. 2008, 38, 4188–4197.
9. (a) Climent, M. S.; Marinas, J. M.; Sinisterra, J. V. Ba(OH)2 catalyst in organic reactions, XIII. Oxidation of benzyl halides to benzaldehydes. React. Kinet. Catal. Lett. 1987, 34(1), 201–206; (b) Bratulescu, G. Synthesis of aromatic aldehydes by a fast method involving Kornblum’s reaction. Synth. Commun. 2008, 38, 2748–2752; (c) Kshirsagar, S. W.; Patil, N. R.; Samant, S. D. Mg–Al hydrotalcites as the first heterogeneous basic catalysts for the Kornblum oxidation of benzyl halides to benzaldehydes using DMSO. Tetrahedron Lett. 2008, 49, 1160–1162.
10. Chen, D. X.; HO, C. M.; Wu, Q. Y. R.; Wu, P. R.; Wang, F. M.; Wu, W. M. Convenient oxidation of benzylic and allylic halides to aldehydes and ketones. Tetrahedron Lett. 2008, 49, 4147–4148.
11. (a) Griffith, W. P.; Jolliffe, J. M.; Ley, S. V.; Williams, D. J. A new ruthenium(VI) oxidant: Preparation, X-ray crystal structure, and properties of (Ph 4 P)[RuO 2 (OAc)Cl 2 ]. J. Chem. Soc., Chem. Commun. 1990, 18, 1219–1221; (b) Peyman, S.; Irai, M-B. Tetrakis (pyridine)silver(II)peroxodisulfate, [Ag(py) 4 ]S 2 O 8 , a reagent for the oxidative transformations. Bull. Chem. Soc. Jpn. 1992, 65, 2878–2880; (c) Bressan, M.; Forti, L. Ruthenium-catalyzed oxidation of alkylaromatics by monopersulfate with preferential oxidative fission of the benzene ring. J. Mol. Catal. 1993, 84, 51–58.
12. Li, C. B.; Zheng, P. W.; Li, J.; Zhang, H., Cui, Y.; Shao, Q. Y.; Ji, X. J.; Zhang, J.; Zhao, P. Y.; Xu, Y. L. The dual roles of oxo diper oxo-vanadate both as a nucleophile and an oxidant in the green oxidation of benzyl alcohols or benzyl halides to aldehydes and ketones. Angew. Chem. Int. Ed. 2003, 42, 5063–5066.
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« Last Edit: March 17, 2017, 02:14:33 AM by byko3y »

Offline atara

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #17 on: March 29, 2017, 10:43:16 PM »
IIRC BnBr will react with DMSO under reflux without needing an activating agent to give the benzyloxysulfonium which undergoes spontaneous in situ decomposition to BzH.

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Re: Benzaldehyde Synthesis - Douchermann
« Reply #18 on: March 31, 2017, 05:14:57 PM »
IIRC BnBr will react with DMSO under reflux without needing an activating agent to give the benzyloxysulfonium which undergoes spontaneous in situ decomposition to BzH.

thanks for that info!
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