Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  ..  11    13    15  ..  25
Author: Subject: toluene --> benzaldehyde
len1
International Hazard
*****




Posts: 595
Registered: 1-3-2007
Member Is Offline

Mood: NZ 1 (goal) - Italy 1 (dive)

[*] posted on 9-4-2008 at 16:51


Quote:
Originally posted by solo
Synthesis of benzaldehyde, heat phenylalanine with 5N NaOH solution for 5 hours, at 110 C, it then decomposes, yielding benzaldehyde........solo


..............source of information,


http://www.ajinomoto.co.jp/amino/e_aminoscience/bc/amino_13....


Somehow I find that hard to believe given the Cannizzaro reaction - which is well known and normally proceeds under much milder conditions.
View user's profile View All Posts By User
MagicJigPipe
International Hazard
*****




Posts: 1554
Registered: 19-9-2007
Location: USA
Member Is Offline

Mood: Suspicious

[*] posted on 9-4-2008 at 16:53


I agree. Also, if it were that easy wouldn't that be the method of choice and be more wide spread?

I think the best method (other than oxidation of BnOH) is hydrolysis of benzal chloride.

[Edited on 4-9-2008 by MagicJigPipe]




"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
View user's profile View All Posts By User This user has MSN Messenger
Fleaker
International Hazard
*****




Posts: 1242
Registered: 19-6-2005
Member Is Offline

Mood: nucleophilic

[*] posted on 10-4-2008 at 16:54
The benzyl cyanide reference


Here is one taken from the literature. Apparently I was wrong about the yield; it is 77% rather than 75% of BzCN from phenyl alanine.

While this isn't related to benzaldehyde, I did offer the paper and several members have asked me for it so I will provide it here for their convenience.

Attachment: Hiegel.pdf (95kB)
This file has been downloaded 5174 times





Neither flask nor beaker.


"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
View user's profile View All Posts By User
Shingoshi
Harmless
*




Posts: 49
Registered: 20-4-2008
Location: Salem, Oregon
Member Is Offline

Mood: No Mood

[*] posted on 21-4-2008 at 00:00


I just couldn't resist joining you guys. Although, that's not meant to be sexist :o in the presence of women. Found this site looking information on azeotropic solutions of Trichloroisocyanuric-acid (TCCA).

Glad I found you!
Shingoshi




The distribution of knowledge must not be the commodity of tyranny.
Solution: The immediate equalization of all knowledge among all beings.
>=(o_6)=>
Expand your mind, Advance our world!
http://www.linuxquestions.org/blog/shingoshi-297853/
View user's profile View All Posts By User
Shingoshi
Harmless
*




Posts: 49
Registered: 20-4-2008
Location: Salem, Oregon
Member Is Offline

Mood: No Mood

[*] posted on 21-4-2008 at 03:15
Yes, precisely


Quote:
Originally posted by Sauron
Welcome

TCCA is a solid. So I am not sure what you mean by an azeotropic solution of TCCA.

Do you mean an azeotropic mixture (of two or more solvents) in which TCCA is soluble?


Acetone and chlorine will make chloroform. I want to try mixing tcca with various solvents to produce special refrigerants. Using Ethanol, produces another refrigerant as well. IRC, it's R-130.

Shingoshi




The distribution of knowledge must not be the commodity of tyranny.
Solution: The immediate equalization of all knowledge among all beings.
>=(o_6)=>
Expand your mind, Advance our world!
http://www.linuxquestions.org/blog/shingoshi-297853/
View user's profile View All Posts By User
not_important
International Hazard
*****




Posts: 3873
Registered: 21-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 21-4-2008 at 03:37


R-130 is 1,1,2,2-tetrachloroethane, moderately nasty stuff. Ethanol + chlorine source generally gives di- or tri- chloro-acetaldehyde, or chloroform, depending on reaction conditions.
View user's profile View All Posts By User
Shingoshi
Harmless
*




Posts: 49
Registered: 20-4-2008
Location: Salem, Oregon
Member Is Offline

Mood: No Mood

[*] posted on 21-4-2008 at 04:37
I admit, I don't have the skill most of you have...


Quote:
Originally posted by not_important
R-130 is 1,1,2,2-tetrachloroethane, moderately nasty stuff. Ethanol + chlorine source generally gives di- or tri- chloro-acetaldehyde, or chloroform, depending on reaction conditions.


My assumptions are often incorrect. ;) But I am only concerned with having a mixture with a very low freezing point.

Question: Should I start another topic, so as not to pollute this one? That's fine by me, and would likely feel better about that also.

Shingoshi

Ok, here's the new thread. http://www.sciencemadness.org/talk/viewthread.php?tid=10387&...

EDIT by Nicodem: Yes, please open a new thread rather than continuing this off topic discussion.

[Edited on 21/4/2008 by Nicodem]

[Edited on 2008.4.21 by Shingoshi]




The distribution of knowledge must not be the commodity of tyranny.
Solution: The immediate equalization of all knowledge among all beings.
>=(o_6)=>
Expand your mind, Advance our world!
http://www.linuxquestions.org/blog/shingoshi-297853/
View user's profile View All Posts By User
Panache
International Hazard
*****




Posts: 1287
Registered: 18-10-2007
Member Is Offline

Mood: Instead of being my deliverance, she had a resemblance to a Kat named Frankenstein

[*] posted on 1-5-2008 at 14:31
Accidental omission


Quote:
Originally posted by Panache
Using a 1L beaker H2SO4 (98%, 100g) was poured into distilled water (500mL) with heavy overhead stirring, the temperature rising from 25C to ~42C. Silver nitrate was added (2.15g) followed by toluene (40g) and heating begun. The temperature rose steadily over the next several minutes to 51C where it began rising quickly, ice blocks were added to the water bath around the beaker and the temperature rise was brought under control, after some 25 minutes the solution was at 65C and held here for a further 90minutes.
Stirring was ceased and the contents were poured over 300g of ice and the contents extracted with two portions of 100mL of dichloromethane.
The benzaldehyde/DCM solution was dried with MgSO4, the DCM and residual toluene evaporated off.
The benzaldehyde was vac distilled without a manometer. One fraction at 52-55C was collected (the flask contents bumping heavily during this process). The cloyingly almond smelling compound was found to have a bp of 177-179C and a density of ~1g/mL. Final mass was 17g or 35%yield, pretty shit really but damm easy and reasonably cheap.
1 drop (~.05mL) was placed into my coffee (short black with 1 sugar) and it tasted damm fine albeit a little dimensionless.


I just re-read this post of mine and realised i omitted the oxidant (ammonium persulphate), 200g were used and added to the sulphuric acid solution. Apologies.




View user's profile View All Posts By User
Klute
International Hazard
*****




Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline

Mood: No Mood

[*] posted on 1-5-2008 at 15:30


It appears that the two articles Trilobite posted in Polverone's thread are not available anymore. Considering how complete the first is on the persulfate/Fe2+/Cu2+ oxidation is, and that the other one does shed some light on the H2O2/Cu+ oxydation, I am attaching them.

Thanks alot to Trilobite for finding and sharing these articles.

Paper 1:
Electron transfert process: Selective syntheses of aromatic aldehydes of industrial interest by catalyzed-peroxydisulfate oxidation
P. Maggioni, F. Minisci
Chimica & Indus. (2), 61, 101-105 (1979)

[Edited on 2-5-2008 by Klute]

Attachment: Paper1.pdf (1.1MB)
This file has been downloaded 1030 times





\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"

-Alice Parr
View user's profile View All Posts By User
Klute
International Hazard
*****




Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline

Mood: No Mood

[*] posted on 1-5-2008 at 16:06


Paper 2:

pH dependence in the Cu+ mediated oxidation of toluene by oxygen or hydrogen peroxide
Okunowski et al.
Rec. Trav. Chim., 109, 103-106 (1990)

(Sorry: forgot to attach file! :) )

[Edited on 2-5-2008 by Klute]

Attachment: pH_dep.pdf (1.4MB)
This file has been downloaded 1136 times





\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"

-Alice Parr
View user's profile View All Posts By User
LSD25
Hazard to Others
***




Posts: 239
Registered: 29-11-2007
Member Is Offline

Mood: Psychotic (Who said that? I know you're there...)

[*] posted on 13-5-2008 at 02:22


I just finished reading the attached article about extracting BnO from aqueous solution and thought it would probably be of interest.

Of rather more interest to myself is whether or not strongly basic exchange resins (generally tertiary amines) could be used in place of hexamine in a modified Sommelet reaction with Benzyl halide (Chloride/Bromide).

I was thinking this would remove the problems associated with phase-transfer one encounters with 2-phase reactions, the n-benzyl amine resin would then be extracted rather simply by filtration. It would be interesting to see whether the benzaldehyde could be regenerated easily or not...

Any ideas?

Attachment: Recovery.BnO.fromAqSoln.with.ExchangeResin.pdf (425kB)
This file has been downloaded 2200 times





Whhhoooppps, that sure didn't work
View user's profile View All Posts By User
manimal
Hazard to Others
***




Posts: 180
Registered: 15-1-2008
Member Is Offline

Mood: ain't even mad

[*] posted on 14-5-2008 at 02:55


Incidently, I wonder if manganese persulfate would oxidize ethylbenzene to phenylacetaldehyde/phenylacetic acid.
View user's profile View All Posts By User
not_important
International Hazard
*****




Posts: 3873
Registered: 21-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 14-5-2008 at 04:00


Quote:
Originally posted by manimal
Incidently, I wonder if manganese persulfate would oxidize ethylbenzene to phenylacetaldehyde/phenylacetic acid.


No, the benzylic carbon is attacked first, giving the aromatic ketone like acetophenone, or benzoic acid.
View user's profile View All Posts By User
Siddy
Hazard to Self
**




Posts: 81
Registered: 8-10-2007
Member Is Offline

Mood: No Mood

[*] posted on 17-5-2008 at 23:25


Quote:
Originally posted by not_important
Quote:
Originally posted by manimal
Incidently, I wonder if manganese persulfate would oxidize ethylbenzene to phenylacetaldehyde/phenylacetic acid.


No, the benzylic carbon is attacked first, giving the aromatic ketone like acetophenone, or benzoic acid.


Which is why you use Cr6+ instead.
Na2Cr2O7 + H2SO4 > Phenylacetic Acid
View user's profile View All Posts By User
not_important
International Hazard
*****




Posts: 3873
Registered: 21-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 18-5-2008 at 00:11


Quote:
Originally posted by Siddy
Which is why you use Cr6+ instead.
Na2Cr2O7 + H2SO4 > Phenylacetic Acid



I suspect that is not so, from

Oxidation of ethylbenzene with aqueous sodium dichromate
Donald G. Lee and Udo A. Spitzer
pp 1493 - 1495; DOI: 10.1021/jo01257a078

Quote:
Several attempts were made to find the proper conditions for the conversion of ethylbenzene to phenylacetic acid. In some twenty-four different experiments the temperature was varied from 126 to 282", the time of reaction was varied from 0.5 to 12 hr, the ratio of oxidant to reductant was varied from 2: 1 to 1 : 2, and the pH was varied from 5 to 11. However, in every experiment the only isolable products obtained were acetophenone and benzoic acid. In general, long reaction times, high temperatures, low pH, and an excess of oxidant tended to favor the production of benzoic acid, while less vigorous conditions decreased the amount of reaction and tended to make acetophenone the main product. Some typical results are presented in Table I, no. 1-10. (Friedman and coworkers5 have also been unable to reproduce the results reported by Reitsema and Allphin.z)
View user's profile View All Posts By User
Siddy
Hazard to Self
**




Posts: 81
Registered: 8-10-2007
Member Is Offline

Mood: No Mood

[*] posted on 19-5-2008 at 23:59


Quote:
Originally posted by not_important

I suspect that is not so, from



The method for the oxidation is very important -as with all oxidations. Just chucking the precursors in a flask and mixing probably wont get you PAA. What your reference obtained is probably accurate. Commonly oxidations dont stop at the desired compound, you have to remove them as they form and make a complex reaction vessel.


You will find a practical method at anyone of your drug site:
http://designer-drug.com/pte/12.162.180.114/dcd/chemistry/ph...

Note, the acetophenone obtained from a more simple approach can give PAA easily
View user's profile View All Posts By User
Siddy
Hazard to Self
**




Posts: 81
Registered: 8-10-2007
Member Is Offline

Mood: No Mood

[*] posted on 27-5-2008 at 23:10


Has anyone had any luck with:

Toluene + Na(OCl)2 > Benzyl Chloride + Benzal Chloride

Benzal Chloride + H2O > Benzaldehyde


n.b. Na(OCl)2 could be any hypochloride salt
H20 could need -OH from salt, eg NaOH.
benzyl chloirde + H2O > Benzyl alcohol
benzyl alcohol [O] > Benzaldehyde
[O] = ammonium persulphate and conc. sulphuric acid.
View user's profile View All Posts By User
not_important
International Hazard
*****




Posts: 3873
Registered: 21-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 27-5-2008 at 23:36


Do you mean Sodium hypochlorite - NaOCl?

The relatively dilute aqueous solutions NaOCl comes in work against it in this case.

Earlier in the thread are discussions on using TCT, the current equavalent of hypochlorites in swimming pool applications. It can also do the oxidation to benzaldehyde. Ring chlorination is a potential problem with chlorine based routes.
View user's profile View All Posts By User
kalacrow
Harmless
*




Posts: 38
Registered: 23-5-2008
Member Is Offline

Mood: No Mood

[*] posted on 9-6-2008 at 20:54
General purpose oxidation, electrochemistry


I've found this thread fascinating, but most especially the bits given by Cycloknight early on. His excellent treatment of an electrocell is really fantastic, and I was wondering if anyone could answer a question I had.

He states late in his posts that you could use the cell to simply generate MAA, remove it from the cell, put in more MAS and continue on. The MAA could be reacted with your starting material outside the cell with "no heating".

Assuming you've worked out the molar amounts, would this simply be a process of:

1) measuring out starting material (let's assume we want vanillin from eugenol, so eugenol to start)

2) Combining it with the MAA

3) With stirring react over time until completion

4) Extract with low boiling point solvent

5) Heat the now depleted MAA (now it should be MAS) to drive off the remaining solvent

6) Save it to turn it back into MAA in the cell

Or.. do you need H2SO4 in there as a promoter? I'm guessing not. Also, in the particular case of eugenol -> vanillin, the classic case has you isomerizing it before oxidizing.. would this be accomplished in situ here?

With a solid (at RT) starting product, would you simply dissolve it in an appropriate solvent to react? I'm assuming you'd need to be careful about that solvent as you'd want one that was relatively impervious to oxidation by this material. Im also aware that this is a complicated question.. so a general answer with one theoretically working example would be great.. not looking for case by case.. just the general theory!

Thanks very much in advance! Im fascinated by electrochem.. I've done all the basic stuff.. cl2, H + O2, and so on. Love the mechanism of it :)

[Edited on 9-6-2008 by kalacrow]
View user's profile View All Posts By User
Siddy
Hazard to Self
**




Posts: 81
Registered: 8-10-2007
Member Is Offline

Mood: No Mood

[*] posted on 16-6-2008 at 22:07


kalacrow, PM Cycloknight he will answer.

AFAIK, no one was successful in converting Benzyl Chloride to Benzaldehyde in 1 step (without going though Benzyl alcohol).
Here is something i read, NOT ATTEMPTED though.


Quote:
Strike
In a flask with stirring is added 126g benzyl chloride, 140g hexamine and either, 500mL 50% aqueous acetic acid or 500mL 60% aqueous ethanol. The solution is refluxed for 2 hours, then 200mL 3N HCL is added and refluxing is continued for 15 minutes more. When cool, the solution is extracted with ether, the ether washed 4 times with water, dried through NaSO4 and vacuum distilled to afford benzaldehyde (yield=70%). The two products are quite fragrant which will give the chemist an idea of the success of the procedure. Did you know that a lot of methylamine is produced as a side product of this reaction? How it can be salvaged Strike has no idea.


So Benzyl Chloride (easily made from toluene) can either be hydrolyzed to benzyl alcohol, then oxidized to benzaldehyde with Persulfate, or directly from chloride to aldehyde with hexamine. Both are not particularly high yields, but as long as you benzyl chloride was easy enough to make who cares.
Alternatively, Len1's write up, advising Benzal Chloride from Cl2+Light radical chlorination of toluene, + HCl > Benzaldehyde.
NB: Benzyl chloride can be made from heating Toluene and Hypochlorite to 105oC, but not Benzal Chloride, it needs Cl2 (TCCA + HCl).
View user's profile View All Posts By User
Ephoton
National Hazard
****




Posts: 463
Registered: 21-7-2005
Member Is Offline

Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.

[*] posted on 27-6-2008 at 18:11


http://en.wikipedia.org/wiki/Sommelet_reaction

yes it has

methylamine im not so sure on as I think it goes through
benzylamine so I can not see how methyl amine can be produced.

it is truly an easy reaction just add water hexamine and reflux
for 2 too 4 hours. steam distill out aldehyde.

alcohol and acetic acid make clean up harder.

[Edited on 28-6-2008 by Ephoton]




e3500 console login: root
bash-2.05#

View user's profile View All Posts By User
brew
Hazard to Self
**




Posts: 96
Registered: 25-4-2008
Member Is Offline

Mood: enthralled

[*] posted on 17-7-2008 at 01:17


I know this thread is to do with the conversion of toluene to benzaldehyde, but I found the following that produced this target compound along with some other things that could be quite useful. I have purchased 250g of almond meal and due to not having a stirring device will not reflux it in ethanol. Instead I will let it sit for some time and add heat and stir occasionally.

Amygdalin is extracted from almond or apricot kernel cake by boiling ethanol; on evaporation of the solution and the addition of diethyl ether, amygdalin is precipitated as white minute crystals. Liebig and Wöhler were already able to find three decomposition products of the newly discovered amygdalin: sugar, benzaldehyde, and prussic acid.[2] Later research showed that sulfuric acid decomposes it into d-glucose, benzaldehyde, and prussic acid (hydrogen cyanide); while hydrochloric acid gives mandelic acid, d-glucose, and ammonia.[3]

The decomposition induced by enzymes may occur in two ways. Maltase partially decomposes it, giving d-glucose and mandelic nitrile glucoside, C6H5CH(CN)O·C6H11O5; this compound is isomeric with sambunigrin, a glucoside found by E.E. Bourquelot and Danjou in the berries of the common elder, Sambucus nigra. Emulsin, on the other hand, decomposes it into benzaldehyde, cyanide, and two molecules of glucose; this enzyme occurs in the bitter almond, and consequently the seeds invariably contain free cyanide and benzaldehyde. An "amorphous amygdalin" is said to occur in the cherry-laurel. Closely related to these glucosides is dhurrin, C14H17O7N, isolated by W. Dunstan and T. A. Henry from the common sorghum or "great millet," Sorghum vulgare; this substance is decomposed by emulsin or hydrochloric acid into d-glucose, cyanide, and 4-hydroxybenzaldehyde.[

I will also be careful if indeed I attempt the decomposition with the potential hydrogen cyanide being produced. Perhaps this is a known method and been already discussed. Perhaps not.
View user's profile View All Posts By User
manimal
Hazard to Others
***




Posts: 180
Registered: 15-1-2008
Member Is Offline

Mood: ain't even mad

[*] posted on 21-7-2008 at 16:19


I tried to make benzaldehyde using the method from US780404 which uses a divided cell to oxidize manganese sulfate to manganese persulfate.

For the cell I used a gallon glass jar into which I placed ~1165 ml of 93% H2SO4 from drain cleaner and ~1478 ml of water, which should equal ~55% acid if my calculations were correct. For the cathode compartment I used a small flower pot which I filled with the same acid mix and suspended in the glass jar. I put into the jar approx. 450 grams of mn sulfate fertilizer, which I assume is the monohydrate (the bag says 31% Mn content, and Mn makes up 32% by weight of the monohydrate).

I used a battery charger set to 6 V with no current control, which passed about 6-8 amps of current. I electrolysed the mixture for around 28 hours or so, until it turned dark purplish black. There was a lot of undissolved sulfate at the bottom which would just resettle when stirred, but with continued electrolysis it too turned brownish purple with white flecks.

When it didn't seem to be doing much else, I removed the electrodes and put ~250 ml of toluene into the jar. I used an electric eggbeater to stir it around, and put it outside overnight to react. In the morning, nothing much had happened except that it had formed an emulsion. This was probably because it had gotten quite cold outside (9 C) which had retarded the reaction. I then placed the jar on a hotplate set to low and commenced mixing. I could smell the benzaldehyde within about half an hour. But after a long time (18+ hours) nothing much more seemed to be happening.

As you can see, it looks almost exactly like the first photo from Hilski's experiment (http://www.sciencemadness.org/talk/viewthread.php?tid=6882&page=3) with this method except that mine only has two layers. If the benzaldehyde is in there, it's trapped in a wicked emulsion. The inside of the jar has the sweet smell of cherries and I can't detect any toluene, but maybe that's because the benzaldehyde is masking the odor. Incidentally, the metal mixers from the eggbeater, which were unaffected after mixing overnight, became badly corroded within an hour after I started warming the mixture. I coated them with epoxy, but after many hours even that started to dissolve. I'll have to find some better mixers if I continue experimenting with this.

According to Hilski, his reaction was done in just 12 hours, but mine is still black, even though I used the same proportions of ingredients. Maybe he used 450 g of the tetrahydrate, and if mine was the monohydrate I would have ended up with a greater mass of oxidant. I don't think significant toluene would have evaporated. I'll probably try adding 100ml more of toluene and continue oxidizing till the mix turns sand colored. Does anyone else have experience with this particular reaction?

Please excuse the shitty quality of my cellphone pic, k thnx.

benzaldehyde.jpg - 65kB




View user's profile View All Posts By User
Dr.3vil
Hazard to Self
**




Posts: 59
Registered: 27-7-2006
Location: Secret Underground Bunker
Member Is Offline

Mood: 4He + 8.7 MeV

[*] posted on 30-7-2008 at 14:31
electrochemical benzaldehyde


I mentioned this in a prior post (kolbe) but figured it needed to be here since the scope of the article is more about the production of benzaldehyde.

Attachment: reduction of aromatic carboxylic acids.pdf (438kB)
This file has been downloaded 3449 times





DR.3vil

- Paper chemistry works the first time every time -
View user's profile View All Posts By User
HeilHamas
Harmless
*




Posts: 3
Registered: 19-9-2007
Member Is Offline

Mood: No Mood

[*] posted on 25-8-2008 at 11:50


Is vacuum distillation or distillation through a column necessary for the toluene/benzaldehyde mix? I tried simple distillation at atmospheric pressure, and got clear toluene and toluene/water azeotrope, and distillate all the way from 85C to about 145C, however after that smoke and orange liquid came through, that looked not unlike the pre-distillation liquid. Is that caused by high temperatures degrading the benz?
View user's profile Visit user's homepage View All Posts By User
 Pages:  1  ..  11    13    15  ..  25

  Go To Top