Synth: Benzaldehyde

fan of zwitterion · Sun Feb 06, 2005 2:40 pm

Benzaldehyde has many routes to it synthesis:

1)Mno2+H2so4+Toluene---->benzaldehyde(low Yield `20%)
2)Ammonia Persulfate+Toluene+[(Cuso4 and or Feso4)]-->Benzaldehyde
3)Toluene+(Na/Ca-Hypochlorite)-->Benzyl Chloride+Hexamine----->Benzaldehyde

I have tested method 2 and 3, and prefer 2 in simplicity, and yield is almost quantative, the hypochlorite method is too dangerous,.

zwit

java · Consumer

It would be nice if you would post the complete synthesis of method 2 which you prefer for safety reasons?....I would guess there is a method to upload articles and put up some reaction drawings in a form of jpeg's or gif's.........java

Guest · Wed Feb 09, 2005 7:48 am

Patent -- CN1446789 -New method for preparing natural benzaldehyde by hydrolyzing bay leaves oil

For those of us that have given the Loomis a go; that is NaOcl- and the Toluene, with the gloriuos run-away temp, of slighty over 105C

"No, I would say, don't do it in the Kitchen",
"do it up on the roof!"
And then coming home fom work to find the kitchen covered in 1.5 Litres of a foul smelling combo of chlorine and Bzcl(benzyl Chloride), really dampened my whole experience,
When a succesfull smaller reaction were done, coming to grips with Boiling toluene, wasn't so bad, even after the hexamine, you still really only get say a 20% final yield.\

Well maybee for larger quantities, but overall I did not feel safe, with the horror of thermal runnaway,

So I began researching further,
Turns out that it can be accomplished so many other ways,

Toluene+Sodium Persulfate( Knew there had to be a use for this tasty little bugger, quietly hiding in the electronics store,.)

I am searching for the patent now, and will post at the end of this thread,

The patent says that yield is over 95%, reaction conditions are a piece of piss, and the co-catalyst are only Cuso4 & Feso4, there is a variety of other Ring protecting catalysts, so don't worry, and there amount is less than 1% : other ingredients.
But in the meantime,

IndoleAmine · Dreamreader Deluxe

I think I have what you're looking for - the thing is called "Elbs persulfate oxidation" and uses ferrous, cupric and/or silver salt catalysts together with sodium persulfate in the oxidation of toluene or (benzyl alcohol) to benzaldehyde....

Patent US4146582 "Process for preparing aromatic aldehydes and ketones", P.Maggioni filed Jan. 31, 1977:

page 4, example 9:

"p-Anisaldehyde

Ferrous-copper catalyst: Anisic alcohol (50g), ferrous sulfate heptahydrate (0.3892g), copper acetate (0.7783g), demineralized water (100ml) and methanol (40ml) are placed in a reactor.
The temperature of the rection mixture is raised to 80°C and a flow of nitrogen is fed to the reactor under fierce agitation while drip feeding a solution of sodium persulfate (103.4g of Na2S2O8 in 335ml of H2O). The reaction is complete within two hours. The products are extracted with diethyl ether and, after evaporation of the solvent, 0.8g of anisic alcohol and 43.86g of p-anisaldehyde are obtained by distillation at 100mm Hg.
The yield of p-anisaldehyde with respect to the reaczted anisic alcohol is 90.5%."

...some time ago, a friend told me he had had this strange dream involving BzOH, some lab glassware, some turquoise and green salts and much of a white, stinging oxidizing agent - and a buttload of BzCHO after the dream was finished - in retrospect I think his dream is just what is claimed in the above patent...

The trick is that with toluene, a 2x molar excess of oxidizing agent is required, whereas with benzyl alcohol, only one molar equivalent is needed. This makes me think the toluene would be oxidized to BzOH anyway before being oxidized further to the aldehyde, and that therefore Elbs persulfate oxidations of hydrocarbons to aldehydes/ketones always proceed via an alcohol intermediate. But that's just my 2 cents.

http://l2.espacenet.com/espacenet/bnsviewer?CY=de&LG=de&DB=EPD&PN=US4146582&ID=US+++4146582A1+I+

Mr. Green

tina_craig · Thu Feb 10, 2005 9:24 pm

What about cinnamaldehyde and sodium carbonate?

Guest · Sun Feb 13, 2005 10:00 am

Have a look here for some recent experiments:

Electrolytic success and from cinnamaldehyde:
http://www.sciencemadness.org/talk/viewthread.php?tid=2223

and:

Toluene chlorination and Sommelet:
http://www.sciencemadness.org/talk/viewthread.php?tid=1751

Guest · Mon Feb 14, 2005 6:44 am

That is a great link, Org,
I wonder, If the poster of thoses pictures, would mind us storing them here, as they are extremely good.

ie, any member with permissions, feel free to upload those pictures here, then display them.

If memory serves me,
Cinnamaldehyde, comes from the Cassia Oil, yes?

I have dreamt the conversion of Toluene to Benzaldehye with Ammonium persulfate, and the results very very good, and very easy,

That's the patent Indole, I'll put it up in the patents as well, along with the loomis patent.

Patent 4,146,582
http://www.shroogle.org/synthetika/viewtopic.php?t=283
thaks indole,

Loomis Patent
http://www.shroogle.org/synthetika/viewtopic.php?t=284
yes, I have seen this reaction done many times,

Using simple catalyst that swim found handy,
Ie, Cuso4 & Feso4, both from Hardware stores

The reaction is fast, and boasts a high conversion, and it's all complety OTC,

Swim, prefers this one, as it happens, around the 70c mark

Here is essentially what I followed

IndoleAmine · Dreamreader Deluxe

Cupric acetate is made very easily by dissolving some CuO in CH3COOH (it takes some minutes for the GAA to dissolve all solids completely, but not really long), distilling away 2/3 of the resulting blue-greenish solution, and placing the remainder in the freezer. Result: nice turquoise crystals of Cu(OAc)2 after filtering.

But nice to hear that CuSO4 works too! :lol:

And when using benzyl alcohol, the methanol isn't required; it just disturbs the steam distillation/extraction of product, and its only purpose is to make the np phase slightly miscible with the oxidant-containing aequous phase: BzOH dissolves in 10x its own volume of H2O, so there is no real need for MeOH. And I would say that with real good stirring, it isn't necessary with toluene either. And way more OTC...

BTW as I speak of toluene and "OTC"-ness: can't sodium persulfate be prepared from 30% H2O2 and Na2SO4? Any ideas?

I_A

IndoleAmine · Dreamreader Deluxe

Yes, cassia oil = cinnamaldehyde.

I heard that it is turned to benzaldehyde in 60% yield by cheaply distilling the whole thing from a few percent of solid KOH - is that right?

Guest · Wed Feb 16, 2005 9:50 am

No, I am not aware of that, most probably I skipped over it at science maddness,

Koh+Cinn.----> Benzaldehyde,

Very interesting,
If someone can verify this, well, I'll just have to look more into it,

syn

IndoleAmine · Dreamreader Deluxe

Strike wrote something about cassia oil being turned into BzCHO cheaply and directly after harvesting the cassia, even "in the fields" - and assumed it would have to be a very easy process.

There's some thread on this topic going on, over at WetDreams, this is where I read about it recently, and I thought "hey! That's probably the thing strike wrote about! Distilling with KOH can really be done even by non-chemists" - as soon as I can, I will look it up and copy&paste it here (WD is inaccessible since the last two hours at least for me, dang internet)...

T_C:

IndoleAmine · Dreamreader Deluxe

Nevermind, I found it:

"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 DEG C.). The resulting material contains 70% benzaldehyde and 30% cinnamaldehyde"

Patent US4617419

(thanks Beebo!)

I_A

IndoleAmine · Dreamreader Deluxe

And another one...

United States Patent 4,673,766
Buck , et al. June 16, 1987
Method of producing benzaldehyde

Abstract

A method is disclosed for producing benzaldehyde by fractionally steam
distilling benzaldehyde from cinnamaldehyde in the presence of hydroxide
catalyst and at a pH on the order of about 11 to about 13. Conversions of
cinnamaldehyde to benzaldehyde can be achieved on the order of about 75% or
more.
Inventors: Buck; Keith T. (Cincinnati, OH); Boeing; Anthony J. (Cincinnati,
OH); Dolfini; Joseph E. (Cincinnati, OH)
Assignee: Mallinckrodt, Inc. (St. Louis, MO)
Appl. No.: 856595
Filed: April 25, 1986

Current U.S. Class: 568/433; 568/458
Intern'l Class: C07C 045/51
Field of Search: 568/433,458
References Cited [Referenced By]

Other References

Guthrie et al., Can. Jour. Chem., vol. 62 (1984), 1441-1445.

Primary Examiner: Helfin; Bernard
Attorney, Agent or Firm: Wood, Herron &Evans
Claims

What is claimed is:

1. A method of making benzaldehyde com- prising

dispersing cinnamaldehyde in water,

converting the cinnamaldehyde to benzaldehyde under the action of heat in the
presence of a catalytic amount of hydroxide ion and at a pH of about 11 to
about 13,

fractionally steam distilling benzaldehyde and acetaldehyde from the
cinnamaldehyde, and

recovering benzaldehyde from the distillate.

2. The method of claim 1 which is conducted at a pH in the range of about 12
to about 12.5.

3. The method of claim 1 wherein the benzaldehyde distillate resulting from
the steam distillation is fractionally distilled for separation of the
benzaldehyde in substantially pure form.

4. The method of claim 1 wherein the acetaldehyde is vaporized during the
course of the conversion while the benzaldehyde is condensed.

5. The method of claim 1 conducted in the presence of an anionic surfactant.

6. The method of claim 1 conducted under shearing agitation to facilitate the
dispersion of the cinnamaldehyde in the water.

7. A method of making benzaldehyde com- prising

dispersing cinnamaldehyde in water in the presence of an anionic surfactant,

agitating the dispersion under the action of heat in the presence of a
catalytic amount of hydroxide ion and at a pH of about 12 to about 12.5 for
the conversion of cinnamaldehyde to benzaldehyde,

fractionally steam distilling benzaldehyde and acetaldehyde from the
cinnamaldehyde in a still having a pot temperature of about 105.degree. C. and
a column temperature of about 99.degree. C., and

fractionally distilling the benzaldehyde from the distillate for the
separation of substantially pure benzaldehyde to obtain a yield of at least
about 75% based upon the cinnamaldehyde.

8. The method of claim 7 wherein cassia oil is employed as a natural source
for the cinnamaldehyde employed in the conversion.
Description

BACKGROUND OF THE INVENTION

The retroaldol reaction of cinnamaldehyde is well known. In this reaction,
cinnamaldehyde is converted to benzaldehyde and acetaldehyde with various
potential side reactions. Recently, for example, an investigation of the
kinetics of the retroaldol reaction of cinnamaldehyde has been reported by J.
Peter Guthrie, et al, Can. J. Chem., Vol. 62, pp. 1441-1445 (1984). While the
conversion of the cinnamaldehyde to benzaldehyde has been long known and well
studied, it has not been heretofore known to produce benzaldehyde from
cinnamaldehyde in substantial yields and favorable reaction conditions for
production of such yields have not been reported.

SUMMARY OF THE INVENTION

This invention is directed to a method of making benzaldehyde by conversion of
cinnamaldehyde in the presence of water with surprisingly high yields
heretofore unachieved. The invention involves the dispersion of cinnamaldehyde
in water and, in the presence of an effective catalytic amount of hydroxide
ion, fractionally steam distilling benzaldehyde from the cinnamaldehyde. The
reaction is conducted at a pH on the order of about 11 to about 13 and,
unexpectedly, within this pH range it has been discovered that a substantial
conversion of cinnamaldehyde to benzaldehyde can be achieved on the order of
about 75% or more. It has also been found that the conversion may be achieved
at such a high pH without adverse side reactions.

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.

During the course of the fractional steam distillation of benzaldehyde from
the cinnamaldehyde, acetaldehyde is also vaporized and removed. The removal of
acetaldehyde thus prevents the forward polymerization reaction which otherwise
competes in the presence of the catalyst. The benzaldehyde which has been
steam distilled is then subsequently fractionally distilled for separation of
the benzaldehyde from other components in the distillate such as minor amounts
of acetaldehyde, terpenes and orthomethoxybenzaldehyde. It has also been found
that a natural source for the cinnamaldehyde such as cassia oil may be
employed containing a substantial amount of the natural cinnamaldehyde. Thus,
a natural product such as cassia oil may be employed in the fractional steam
distillation method of this invention and still the significant yields on the
order of about 75% or more are achieved.

DETAILED DESCRIPTION

The following detailed operating example illustrates the practice of the
invention in its most preferred form, thereby enabling a person of ordinary
skill in the art to practice the invention. The principles of this invention,
its operating parameters and other obvious modifications thereof will be
understood in view of the following detailed procedure.

OPERATING EXAMPLE

A solution was made up from 38.6 lbs. sodium hydroxide, 4 lbs. sodium lauryl
sulfate and 10 liters antifoam agent in 760 gallons of water. The solution was
stirred until a homogeneous solution was obtained. Then, 1320 lbs. of cassia
oil were placed in a 1150 gallon still. The oil contained approximately 72% by
weight of cinnamaldehyde. The still had a pot volume of about 1150 gallons
onto which was mounted a 4 foot fractionating column containing 1".times.1"
ceramic tubes and a water cooled condenser was thereafter connected in series
for condensing the benzaldehyde-water azeotrope.

The above prepared sodium hydroxide solution was then added to the cassia oil
and introduced into the pot of the still. The pot was equipped with a stirrer.
Using pressurized steam and vigorous stirring, the pot was heated to reflux
with a pot temperature of 105.degree. C. Reflux was established with a column
head temperature of about 99.degree. C. Once reflux was established, it was
continued for about 1 hour. During the course of the conversion of the
cinnamaldehyde in the cassia oil to benzaldehyde, pH was monitored and was
maintained at about 12 to about 12.5. In the event the pH fell below about 12,
sodium hydroxide was added to bring the pH back up to the range of about
12-12.5. After refluxing for about 1 hour, take-off of the water-benzaldehyde
azeotrope was initiated. The water cooled condenser was operated at
100.degree. F. thereby enabling the water-benzaldehyde azeotrope to be
condensed and collected in a chilled receiver. The acetaldehyde by-product was
principally vaporized at the temperature of the condenser and was taken off as
vapor. The distillate principally containing benzaldehyde in an amount of
about 75% or more with minor amounts of cinnamaldehyde, terpenes,
orthomethoxybenzaldehyde and acetaldehyde was obtained. The crude benzaldehyde
was thus collected in a chilled receiver and, in a continuous feed operation
the condensed water was continuously fed back to the still to replace what had
been taken off and the distillation of the azeotrope continued. The fractional
steam distillation of the crude benzaldehyde continued until about 670 lbs. of
crude benzaldehyde were obtained. The crude distillate containing benzaldehyde
was then dried under vacuum and fractionally distilled under vacuum of about
29" thereby providing a boiling point for the benzaldehyde at about 70.degree.
C. in order to obtain a substantially pure benzaldehyde free from residual
terpenes and other impurities.

Thus, by means of practicing the above process, the objectives of this
invention are achieved in that cinnamaldehyde is converted into benzaldehyde
in substantially pure form even from the natural source of cassia oil.
Surprisingly, it has been found that substantial yields in excess of 75% or
more of substantially pure benzaldehyde are achieved by this method. Moreover,
it has been found that there is a surprising window of high pH at which the
conversion may take place in a fractional steam distillation column in order
to separate the benzaldehyde and acetaldehyde from the reaction mixture and
still avoid the adverse side reactions from occurring.

Having described this invention and its operating parameters, variations may
be achieved without departing from the spirit and scope hereof."

Now THAT'S a cool one, isn't it? 75% conversion through simple distillation! Did you read the "oerating example"? They use straight cassia oil... Cool

I_A

IndoleAmine · Dreamreader Deluxe

And acetaldehyde - the by-product of above reaction - is useful by its own already. Overall, nice thing: benzaldehyde and acetaldehyde VERY cheaply from cassia oil...

nyarlothotep · Sat Feb 19, 2005 7:57 am

Any guesses?
They left that part out.....maybe i'm just supposed to know?

The entire surfectant use is still a new concept to me.