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[*] posted on 15-6-2011 at 01:09
cinnamon oil to benzaldehyde


My lab was at my friends house and we did our little experiments in his garage. Unfortunately his mother has found a new guy and he is now living in the house and has started asking questions about us. I cant experiment in there anymore and it would be far too difficult for me to do it anywhere else. Also, I'm still living at home with my parents and they'd kill me if they sore me doing those sort of things :(
Thus I'm hoping to find people who have already done these things and can help me out, it sucks I know :(

EDIT by Nicodem: I split questions' off topic posts from the toluene --> benzaldehyde thread and the replies, and merged them in this thread he finally created for his questions.

[Edited on 25/12/2011 by Nicodem]
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[*] posted on 26-8-2011 at 15:59
benzaldehyde from cinnamon oil


Quote: Originally posted by CycloKnight  
Hi peeps, been off the forum a good while but its good to be back :).

I’ve significantly improved the original batch method I posted last year, what follows is my latest method.

This approach uses the same setup as the last steam distillation variation graphically depicted in in this thread.

Basically, the items used were:
hot plate, pressure cooker steam generator & associated tubing, etc
3L 3-neck RBF & mantle
vigreux column, right angle bend & still head
condenser
Vacuum pump & glassware for purfying the final product & recycling unreacted cinnamaldehyde.

chemicals: 2 litres tap water, lecithin, cinnamon oil, NaOH

Essentially, a large reaction vessel and a means of steam & vacuum distilling are all the equipment really required.


Begin by setting up all equipment, add 2 L water & ~1.5g lecithin.
The first variation is to use OTC sodium hydroxide instead of sodium carbonate, simply add the alkali to adjust the pH within the range of 12-13, only small amounts are required.

The second variation is to slowly drip in the cinnamon oil during the course of the reaction, the benzaldehyde being steam distilled as it forms. Begin the addition once the pH adjusted solution has heated to boling temperature and the steam is passing though the solution.

The third variation is to stop the cinnamon oil addition after 5 min, then check the distillate. If benzaldehyde is clearly distilling over, then continue with the addition.
A crude test is to simply taste the steam distillate as it drips into the receiving vessel, if it burns your tongue off, then you're doing well. If it tastes sweet, then significant quantities of cinnamon are being carried over. Should this not change after a short while, then double check the pH !

Provided that the pH is correct and the cinnamaldehyde content is high (70%+) then benzaldehyde laden distillate should start collecting almost immediately after the addition has begun.
However, if it is not, wait for the benzadehyde to start collecting, THEN continue with the addition. This prevents unnecessary amounts of cinnamaldehyde being steam distilled at the start of the process, which is a serious problem with the old batch mode reaction.

Note that by slowly dripping the cinnamon oil instead of adding it all at once to the reaction mix, single run conversion is increased by 20-30%.

Ensure the rate of cinnamon oil drip rate is approximately equivalent to the quantity of oil being steam distilled, thus maintaining high dilution in the reaction mixture.

After 300 to 500 ml of cinnamon oil had been added, the drip rate is stopped and the steam distillation continued until all the aldehyde has been steam distilled from the reaction mix. If using less than 2L of water, then adjust proportionally to maintain the same dilution. At this point, dump the mix and replace with clean pH adusted water with at least ~1.5g lecithin.
This step removes tar and other junk that slows down the reaction and reduces benzaldehyde production. Significantly reduced tar formation will also result from periodically carrying out this step (very imporant if high yields are desired).
Also note that with this method, the pH tends to slowly drop over time during the course of the steam distillation, so check the pH every couple hours, and top up with NaOH if and when required. Its preferable to simply add small amounts concentrated NaOH solution when topping up, using a dropper makes the alkali addition much simpler since NaOH pellets will rapidly collect moisture and stick to the sides of the reaction vessel.

Efficiency is further improved if the steam distillate (after oil separation) is also extracted with DCM, though this isn't absolutely necessary.

Once the the product oil is pooled, vacuum distillation will remove the benzaldehyde - no need to vacuum distill the recycle cinnamon aldehyde, just drip it into the steam distillation vessel, just as with the cinnamon oil feed. Expect the quantity of unreacted cinnamon aldehyde to be circa 25%, but if the reaction mix was kept clean during the process then it may be considerably less. The benzaldehyde distillate is clear, & much purer than the original solvent extraction method that doesn't employ the steam distillation. Give the batch solvent extraction a rest folks, use the steam distillation variation if producing benzaldehyde from cinnamon oil!
Far, far less work.

Using the above approach, overall molar conversion to benzdehyde is at least 80%.

I’ve managed higher conversion efficiencies (~90%), but the reaction efficiency is subject to variation according to varying reaction conditions, i.e. feed rate, reaction mix volume (i.e. dilution), and the quantity of cinnamon oil fed to the reaction mix before changing the solution. >80% seems to be a realistic overall figure.

Also...
Remember to keep the reaction mix free of tar & cinnamon oil impurities as much as possible to give consistent high yields.

If dripping the aldehyde into the mixture isn't practical for any reason, you can periodically add the cinnamon oil in small batches, say 20-50 ml at a time to give good conversion, but expect a little more cinnamonaldehyde to distill over.


OK, here cyclonknight described an attractive process for making benzaldehyde from cinnamon oil by slowly dripping the cinnamon oil into the already boiling water with dissolved NaOH at around a PH of 12 to 13.
What I dont understand is that on the wikipedia they say that benzaldehyde is converted into two other chemicals when exposed to highly concentrated NaOH, and I quote

"Benzaldehyde undergoes disproportionation upon treatment with concentrated alkali (Cannizzaro reaction): one molecule of the aldehyde is reduced to the corresponding alcohol and another molecule is simultaneously oxidized to sodium benzoate."

So if the cinnamon oil is being converted to benzaldehyde, and is steam disstilled out, why isn't the benzaldehyde being converted into other products as described by the wikkipedia?
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[*] posted on 27-8-2011 at 06:59


A concentrated solution of NaOH will in fact disproportionate aldehydes. However, this is by far not a concentrated solution. If you notice, Cycloknight said "only small amounts [of NaOH] are required." A concentrated solution of NaOH will be pH 14, whereas a very dilute solution will be 12-13.

Thus, the Cannizzaro shouldn't occur very readily in these conditions.




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[*] posted on 27-8-2011 at 16:45


Quote: Originally posted by questions  
Quote: Originally posted by CycloKnight  
OK, here cyclonknight described an attractive process for making benzaldehyde from cinnamon oil by...



This is the easiest way (best)!! A while back I dismissed this method due to there being no cinnamaldehyde available. I just found a source of trans-cinnamaldehyde. Does anyone know if it will work for the trans isomer of cinnamaldehyde? Does anyone know of a good source of cinnamaldehyde? :cool:

[Edited on 28-8-2011 by MeSynth]
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[*] posted on 27-8-2011 at 16:59


trans-Cinnamaldehyde is the molecule that occurs in nature so it will work with trans-Cinnamaldehyde since this is what is found in essential oil of cinnamon.
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[*] posted on 27-8-2011 at 17:38


Here is the actual example described in the patent used by cyclo.

-------------------------------------------------------------------------------------------------

EXAMPLE II

Preparation of Natural Cinnamaldehyde and Natural Benzaldehyde

Into a three neck flask equipped with stirrer, thermometer and reflux condenser is placed 10 grams of cassia oil and 100 ml of a 3% aqueous sodium carbonate solution. Boiling chips are added and a water-washed stream of nitrogen is passed over the reaction mass to help prevent oxidation of the formed benzaldehyde. The mixture is heated to reflux and refluxed for a period of 7 hours (100° C.). The resulting material contains 70% benzaldehyde and 30% cinnamaldehyde.

-------------------------------------------------------------------------------------------

Cassia oil is not pure cinnamaldehyde so it is more than likely that you would want to use less cinnamaldehyde if that is what your using for the reaction. In the pattent they said their cassia oil contained 88% cinnamaldehyde. That means that only 8.8 garms of cinnamaldehyde was used.
to prevent oxidation of the benzaldehyde they used a water washed stream of nitrogen. The lose of benzaldehyde to oxidation shouldn't be so bad that you need a stream of nitrogen.
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[*] posted on 27-8-2011 at 18:07


What I hate about making benzaldehyde from cinnamon oil is that is is very difficult to separate the benzfrom the cinamon and so usually a solvent based extraction must be employed about four times followed by a vacuum disstilation. If you ask me it's still alot of work and the process requires the right equipment and glassware.
If we could find a way to separate the benzaldehyde from the cinnamon oil without the need of vacuum disstillation than that would make the process much easyer and using sodium metabisulfite is not a good idea to recover the benzaldehyde because it will also form a duct with the cinnamon aldehyde, for it's name suggests it to is an aldehyde :(
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[*] posted on 27-8-2011 at 20:03


The sodium bisulfide method could work. Benzaldehyde has a boiling point that is close to 50 degrees less than that of cinnamaldehyde. So when the crystals are heated to 170 degrees the benzaldehyde will boil out while the cinnamaldehyde will just liquify (in theory). I have not read about the effects of heating the sodium bisulfide adduct of cinnamaldehyde and I have not had the pleasure of conducting any tests so for all I know the crystals will explode.
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[*] posted on 27-8-2011 at 20:14


Here is a relatively usless link. http://www.scientific.net/AMR.183-185.1942

You will find a little more info about the sodium bisulfide adduct of cinnamaldehyde.

-------------------------------------------------------------

And here is a post by: arsphenamine
in the forum titled: Cinnamaldehyde from cinnamon bark powder
_

Aldehydes have classically been purified by precipitation of the bisulfite adduct, filtration and washing of the solid, and regeneration by gentle hydrolysis with bicarbonate or acid as circumstances dictate.

TLC roughly shows you how impure it is. GC exactly shows you, but doing TLC using coffee filter strips is often all you need.

You can purify by vacuum distillation if you need something analytically pure although you lose some product to the pot.

OrgSynth has a good prep for 3-methyl phenylpropanal.

The money shot:

A completely pure sample of the aldehyde is readily obtained by stirring the crude aldehyde with excess saturated aqueous sodium bisulfite solution for several hours, filtering the solid bisulfite adduct, washing with ether, and liberating the aldehyde with excess aqueous sodium bicarbonate.


------------------------------------------------------------------

From what I read above I found that I can purify a crude mixture of aldehyde by a sodium bisulfide adduct. This is however not going to separate the benzaldehyde from the cinnamaldehyde and aldehyde. So far the only way I can imagine is fractional distillation which is probably the best way.

[Edited on 28-8-2011 by MeSynth]

Check this clip out! I got it from patent #4673766

___


In a preferred mode of conducting the method, the cinnamaldehyde is dispersed in the water in the presence of shearing agitation and a surfactant. In another aspect of this invention, it is preferred to employ an anionic surfactant such as sodium lauryl sulfate. Preferably, the hydroxide ion is furnished by means of sodium hydroxide which also achieves the pH in the range of about 11 to about 13. It has critically been determined that the fractional steam distillation of benzaldehyde from the cinnamaldehyde must be conducted at a pH within the range of about 11 to about 13, preferably about 12 to about 12.5. Below and above this pH range, very poor conversions are obtained of 50% or far less and competing reactions interfere with the production of benzaldehyde. Outside of this critical pH range, side reactions, polymerization and other adverse reactions prohibit any significant yield of benzaldehyde. Yet, within the pH range of about 11 to about 13, especially about 12 to about 12.5, significant yields on the order of 75% or greater are achieved and benzaldehyde is recoverable in substantially pure form free of side reaction products. These results are considered to be unexpected especially at the high pHs of the reaction where it may have been expected that side reactions would have significantly lessened or prevented the yield for the desired product.

___

This may be the method I've been looking for.

[Edited on 28-8-2011 by MeSynth]

------------------------------------------------------------------

Again I took the liberty. Please correct anything wrong with the following.... :)


I dont think foaming should be a problem when done on a small scale like the one I'm about to describe. After doing the math this is what I came up with. This is the scale I would do it at.

4673766

A stir bar and 32.5 ml of cinnamaldehyde is added to a 500ml round bottom flask (I'm going to do it in a 3 necked 500ml RB 14/20) followed by 222.5 ml of DH2O followed by just enough sodium hydroxide to make the ph 12-12.5 (something like 1.386 grams). A reflux adaptor is then fitted to this flask. Attach another condencer to the top of the reflux condencer and set it up for distilation. The reflux adaptor is then flooded with ice cold water. The mixture is then heated on an oil bath to reflux at 105C. The reflux is to be held for one hour with carful monitoring of the ph (to monitor it I will use the free neck of the 3 necked rb flask) making sure to keep it within the range of 11 - 13. If the ph is starting to drop sodium hydroxide is added (this could be done by adding a drip or two of concentrated aqueous sodium hydroxide via addition funnle). After one hour the condencer set up for distillation is flooded with ice cold water. After it has cooled considerably the reflux condencers water supply is replaced with warm tap water and then left alone (or you can keep the waters temp set to 37.7 like the patent says) creating a temperature within the reflux condencer that will allow the water vapor to escape. The condencer set up for distilation will condence the vapor containing the benzaldehyde. As water leaves the mixture more water should be dripped in at the same rate it is leaving and the ph should still be monitored. This is not covered in the patent but I'm sure it is important.

The patent then distills the benzaldehyde under a vacuume that allows it to boil at 70C. This is done to separate it from the impurities. I'm sure this step could be skipped by doing a work up with sodium bisulfite.



[Edited on 28-8-2011 by MeSynth]
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[*] posted on 27-8-2011 at 20:38


Thanks guys, I really appreciate your thoughts on my questions :)

And it's good to see that we're all participating in helping one another, keep up the good work :)
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[*] posted on 30-8-2011 at 13:05


Hey guys

I was told by someone that the cannizaro reaction only happens when the solution is alkalai and this is when the ph is 14 plus. I'm confused because i'm thinking about a reaction that happens between the ph range of 12 to 13 to make benzaldehyde from cinnamon aldehyde as previously disscussed
.
Thus does the cannizaro reaction only happen at a ph of at least 14 or can it even happen at a range of say between 12 and 13 with aldehydes?
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[*] posted on 22-9-2011 at 02:24


I'm trying to find out at what PH the cannizarro reaction will happen at, does anyone know?
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[*] posted on 30-10-2011 at 22:27


Does anyone know what drip rate cyclonight used when he made benzaldehyde by slowly driping the cinnamon oil into the boiling mixture of water and NaOH.
That is, how many seconds between each drop of cinnamon ?
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[*] posted on 31-10-2011 at 01:06


Quote: Originally posted by CycloKnight  
Hi peeps, been off the forum a good while but its good to be back :).

I’ve significantly improved the original batch method I posted last year, what follows is my latest method.

This approach uses the same setup as the last steam distillation variation graphically depicted in in this thread.

Basically, the items used were:
hot plate, pressure cooker steam generator & associated tubing, etc
3L 3-neck RBF & mantle
vigreux column, right angle bend & still head
condenser
Vacuum pump & glassware for purfying the final product & recycling unreacted cinnamaldehyde.

chemicals: 2 litres tap water, lecithin, cinnamon oil, NaOH

Essentially, a large reaction vessel and a means of steam & vacuum distilling are all the equipment really required.


Begin by setting up all equipment, add 2 L water & ~1.5g lecithin.
The first variation is to use OTC sodium hydroxide instead of sodium carbonate, simply add the alkali to adjust the pH within the range of 12-13, only small amounts are required.

The second variation is to slowly drip in the cinnamon oil during the course of the reaction, the benzaldehyde being steam distilled as it forms. Begin the addition once the pH adjusted solution has heated to boling temperature and the steam is passing though the solution.

The third variation is to stop the cinnamon oil addition after 5 min, then check the distillate. If benzaldehyde is clearly distilling over, then continue with the addition.
A crude test is to simply taste the steam distillate as it drips into the receiving vessel, if it burns your tongue off, then you're doing well. If it tastes sweet, then significant quantities of cinnamon are being carried over. Should this not change after a short while, then double check the pH !

Provided that the pH is correct and the cinnamaldehyde content is high (70%+) then benzaldehyde laden distillate should start collecting almost immediately after the addition has begun.
However, if it is not, wait for the benzadehyde to start collecting, THEN continue with the addition. This prevents unnecessary amounts of cinnamaldehyde being steam distilled at the start of the process, which is a serious problem with the old batch mode reaction.

Note that by slowly dripping the cinnamon oil instead of adding it all at once to the reaction mix, single run conversion is increased by 20-30%.

Ensure the rate of cinnamon oil drip rate is approximately equivalent to the quantity of oil being steam distilled, thus maintaining high dilution in the reaction mixture.

After 300 to 500 ml of cinnamon oil had been added, the drip rate is stopped and the steam distillation continued until all the aldehyde has been steam distilled from the reaction mix. If using less than 2L of water, then adjust proportionally to maintain the same dilution. At this point, dump the mix and replace with clean pH adusted water with at least ~1.5g lecithin.
This step removes tar and other junk that slows down the reaction and reduces benzaldehyde production. Significantly reduced tar formation will also result from periodically carrying out this step (very imporant if high yields are desired).
Also note that with this method, the pH tends to slowly drop over time during the course of the steam distillation, so check the pH every couple hours, and top up with NaOH if and when required. Its preferable to simply add small amounts concentrated NaOH solution when topping up, using a dropper makes the alkali addition much simpler since NaOH pellets will rapidly collect moisture and stick to the sides of the reaction vessel.

Efficiency is further improved if the steam distillate (after oil separation) is also extracted with DCM, though this isn't absolutely necessary.

Once the the product oil is pooled, vacuum distillation will remove the benzaldehyde - no need to vacuum distill the recycle cinnamon aldehyde, just drip it into the steam distillation vessel, just as with the cinnamon oil feed. Expect the quantity of unreacted cinnamon aldehyde to be circa 25%, but if the reaction mix was kept clean during the process then it may be considerably less. The benzaldehyde distillate is clear, & much purer than the original solvent extraction method that doesn't employ the steam distillation. Give the batch solvent extraction a rest folks, use the steam distillation variation if producing benzaldehyde from cinnamon oil!
Far, far less work.

Using the above approach, overall molar conversion to benzdehyde is at least 80%.

I’ve managed higher conversion efficiencies (~90%), but the reaction efficiency is subject to variation according to varying reaction conditions, i.e. feed rate, reaction mix volume (i.e. dilution), and the quantity of cinnamon oil fed to the reaction mix before changing the solution. >80% seems to be a realistic overall figure.

Also...
Remember to keep the reaction mix free of tar & cinnamon oil impurities as much as possible to give consistent high yields.

If dripping the aldehyde into the mixture isn't practical for any reason, you can periodically add the cinnamon oil in small batches, say 20-50 ml at a time to give good conversion, but expect a little more cinnamonaldehyde to distill over.


OK everyone, I've given this alot of thought and now I need everyones help on this because I am not in a possition to do the experiment myself.

When cyclonight said that after the 300-500ml had finished dripping the cinnamon oil into the 2L of boiling water with NaOH in it, how long did it take for the whole 300-500ml to completely drip in because he never said what the drip rate was?
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[*] posted on 8-11-2011 at 17:47


does anyone know how long it took cyclonnight to drip the 300 to 400ml of cinnamon oil into the 2l of boiling water with naoh in it at ph 12to 13?

ANYONE?

ANYONE AT ALL?..........
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[*] posted on 8-11-2011 at 17:56



Quote:

Ensure the rate of cinnamon oil drip rate is approximately equivalent to the quantity of oil being steam distilled, thus maintaining high dilution in the reaction mixture.



That long.
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[*] posted on 11-11-2011 at 04:19


OK Neil, I appreaciate your input put there are several factors that will affect how long it takes for the benzaldehyde/cinnamon disstillate to come over, some are;

1) the drip rate
2) the amount of steam that is blown into the solution
3) the presure of the steam as it goes into the solution

these ar the three crucial factors that cyclonights posts have ommited, and naturaly if you were to alter one/some/all of the three points i've mentioned above you will get different disstilation amounts and different conversion amounts into benzaldehdye.
I'm wanting to know that based on "cyclonights" conversions (circa 75%), how long did it take him to get te whole300ml to 500ml through the solution

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[*] posted on 11-11-2011 at 06:29


Quote: Originally posted by questions  
1) the drip rate
2) the amount of steam that is blown into the solution
3) the presure of the steam as it goes into the solution
It sounds like you've got some good parameters for an experimental design. Please report what you find here. I'm sure others will appreciate it.
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[*] posted on 11-11-2011 at 07:08


doing that experiment would be the one thing i would love to do, but unfortunately I am living with my mum and dad and they dont like the idea of me doing stuff like that. Also I have not the equipment and location right now to do the experiment.
Thus, I'm just wanting to see if anyone else has done the experiment and can shed some light on it.
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[*] posted on 11-11-2011 at 08:04


Quote: Originally posted by questions  
I am living with my mum and dad and they dont like the idea of me doing stuff like that. Also I have not the equipment and location right now to do the experiment.
So why do you care? If you can't do the experiment, you wouldn't be able to do the synthesis either.
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[*] posted on 11-11-2011 at 18:34


I'm only interested in knowing how it works for my own knowledge. I'm curious.

Also, what would happen if benzaldehyde made contact with aluminum?
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[*] posted on 16-11-2011 at 01:26


Quote: Originally posted by questions  
I'm only interested in knowing how it works for my own knowledge. I'm curious.

Also, what would happen if benzaldehyde made contact with aluminum?


Depends on the temperature. I know fairly certainly that if the temperature of the aluminum is less than -150C, the benzaldehyde will likely freeze and nothing further will occur. If the aluminum is at 3000C or above the benzaldehyde will likely be destroyed quickly. Other than that I can't say for sure.
Hope this helps!




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[*] posted on 20-12-2011 at 02:04


There is no easy way to make benzaldehyde, I think the best way is to get it from a chemical company that use it for their business and try buying it from them.

I have tried most of the benzaldehyde making methods and they all yeild very little product.
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[*] posted on 23-12-2011 at 19:18


I cant do the experiment myself right now as I'm in the process of relocating but my situation is this;

I'm wanting to try cyclonights method that he explained on page six where he slowly dripped the cinnamon oil into the boiling solution of NaOH with a ph of around 12.6 and had steam blowing in at the same time to disstill the formed benzaldehyde.
The product he obtained was about 75% benzaldehyde and the other 25% was the unreacted cinnamon oil. He then took this product and vacuumed disstilled it to get pure benzaldehyde, very interesting method.

He doesnt state how many seconds that were between each drip of cinnamon as it dripped into the 2L boiling solution of water and NaOH and he doesnt state how long it took for the product to be completely distilled.

If I was to use the same amount of cinnamon oil that cyclonight used but instead of using 2L of boiling solution of water and NaOH like he used, say I used an 8L of solution instead, does that mean I would need four times as much steam pressure to get the same amount of product to disstill over?
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[*] posted on 24-12-2011 at 02:26


Is there a reason people are so intrigued with methods other than toluene, uv, chlorine, then hydrolysis with hcl to benzaldehyde. Its reliable, scalable and safe, if you consider producing chlorotoluenes safe.

Also when i tried the method of dripping the cinnamon oil into the naoh i found it considerably superiorto bleed the cinnamon oil into the steam line, this created a massive dispersion of fine oily droplts.

Also don't try doing this in glass, it doesn't work reliably at those pressures.simply use two camping gas cylinders, one for generating the steam, the other for the reaction. Lead the outlet vapour into a glass condenser, downwards, a coiled jacketed one to handle the shitloads of steam one needs to condense, also did i mention this method is unreliable, inconsistent and a pain in the arse. :D




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