Sciencemadness Discussion Board

Benzaldehyde Smell

kemm10 - 11-5-2007 at 17:46

Most of what I've read about Benzaldehyde's odour, says it smells like almonds, but all the almond extract I've bought smells like cherries. Some sources, such as this one at http://www.monell.org/Newsletters/Monell_Fall00.pdf say it has a cherry-almond aroma. Why is there this difference in the smell? As an experiment, I mixed some toluene into a solution of acetone and sodium persulfate in the hopes of getting an almond extract odour, but instead got an almond odour. Is the difference in odours caused by the solvents and concentrations of benzaldehyde?

[Edited on 12-5-2007 by kemm10]

evil_lurker - 11-5-2007 at 18:09

Definatly smells like cherries.

I have some benzyl alcohol and due to the air being let in during opening and permiating thru the walls of the plastic jug there is that hint of cherries.

12AX7 - 11-5-2007 at 20:04

At work, there's this roll of sheet rubber stock that smells amazingly like cherries or a hint of cinnamon. Now, I know cinnamonaldehyde is responsible for that specific spicy aroma, but if the odor is cherries, why doesn't it smell like almonds like benzaldehyde does? More to the point might be, why don't cherries smell like almonds? (Maraschino-processed cherries aside!) I never did find a chemical claiming it is responsible for any portion of the odor of cherries, though I've seen a few references to compounds smelling like it (benzaldehyde obviously, and amazingly, tosylmethyl isocyanide).

Tim

Sauron - 12-5-2007 at 05:12

More specifically, benzaldehyde smells like burnt almonds. So does HCN.

Now if you really want to be confused, make some cherry brandy (by fermenting mashed cherries then distilling the resulting wine. Do you know what it will taste like?

Almonds. Burnt almonds. If you want to check this without all the labot buy a bottle of Kirsch (cherry) brandy, the real European stuff not the drug store crap mixed up from extracts. Real Swiss or German Kirsch.

And all makers of eau-du-vie, strong European fruit brandies will tell you that they must build a special cyanide trap into the still, because the pits at the center of most fruit release a lot of cyanide.

unionised - 12-5-2007 at 12:22

Most of the smell of almonds is due to benzaldehyde so the 2 smell pretty much the same. HCN (and nirobenzene) smell pretty similar but not the same. I can't find any information on what cherries smell of except that benzaldehyde is a component,

Eclectic - 12-5-2007 at 12:55

Cherry smell might be benzaldehyde+acetaldehyde+ethanol+ethyl acetate...

Components with fruity associations making the difference. Some of the cherry flavor formulations's I've seen use p-tolualdehyde instead of or in addition to benzaldehyde.

sonbob115 - 10-6-2009 at 17:28

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fiscalite assurance vie

kclo4 - 10-6-2009 at 19:38

Almonds and cherries are related so it makes sense to me at least that they would both contain the same crap - benzaldehydes, cyanides, and whatever that parent compound is.
Apricot seeds, though probably not the best thing to eat, taste a lot like almonds also and I believe they contain cyanide. Well, some sort of poison.

JohnWW - 10-6-2009 at 23:52

Quote: Originally posted by kclo4  
Almonds and cherries are related so it makes sense to me at least that they would both contain the same crap - benzaldehydes, cyanides, and whatever that parent compound is. Apricot seeds, though probably not the best thing to eat, taste a lot like almonds also and I believe they contain cyanide.
They, or at least their kernels, contain amygdalin (laetrile), which is a cyanosaccharide of benzaldehyde, with the shorthand structure C6H5-CH(CN)-O-(Glucose)-(Glucose). The C attached to the aromatic ring is optically active. When the kernels containing amygdalin are ingested, the diglycoside unit and the CN are cleaved off, leaving also C6H5CHO and HCN, with their characteristic almond odors and tastes.

This formation of HCN is a natural chemical protection against insects. It is probably also the basis for the use of amygdalin, as or derived from almond/peach/cherry/apricot/plum kernels, as a treatment for and preventative of cancer, which if correct would mean that cyanide preferentially affects cancerous and precancerous cells.

[Edited on 11-6-09 by JohnWW]

setback - 11-6-2009 at 12:31

Red candied cherries are almond flavored. That might be what's tripping you up there.

sparkgap - 11-6-2009 at 17:58

A memory from early childhood was that my grandfather taught me a lot of tricks in catching butterflies. One among them is that as soon as I catch one, I should place the butterfly in a closed jar with bruised cherry laurel leaves to knock the butterfly out. I commented on how good smelling it was, but I was warned not to inhale the sweet-smelling leaves.

Not until I found out about the preponderance of cyanogenic glycosides in the rose family (of which apricots, peaches, almonds, cherries, and cherry laurels are proud members) did I understand my grandfather's warning.

In any event, I probably can't distinguish the odor of prussic acid from benzaldehyde (I can smell both).

@John: there are glycosidase enzymes present in those plant parts that are activated when the cells are injured. The Laetrile nonsense has already been roundly discredited by the American Cancer Society, just so you know.

sparky (~_~)

JohnWW - 11-6-2009 at 18:09

Quote: Originally posted by sparkgap  
(cut)@John: there are glycosidase enzymes present in those plant parts that are activated when the cells are injured. The Laetrile nonsense has already been roundly discredited by the American Cancer Society, just so you know.
The so-called "American Cancer Society" is just a gravy-train, or cash cow, for its executives! I understand that something like 90% of the donations it receives go on administration costs. Of course they would want to discredit any naturopathic cures or preventatives or palliatives for cancer, because it suits them to do so, being "in the pocket" of the big drug companies. So that they should "rubbish" amygdalin/laetrile, because it is not a drug that can be patented and sold for huge profits, is not surprising.

Panache - 14-6-2009 at 16:27

When i tasted goanna for the first (and only) time i thought it tasted a little like chicken, the Aboriginals that cooked it for me laughed and said they thought chicken tasted like goanna.

Cherry flavour and almond flavour are the same concept.

I have stripped thick, high-voltage underground cable before. It was copper, oiled in some way, then wrapped in brown paper, then a polymer, these were coiled thrice together, wrapped in more paper, then protected by steel/rubber belting, then tarred. Interestingly the grease the brown paper layers were soaked in smelled very strongly of benzaldehye and i've always wondered if this was compounded into the grease as an oxygen scavenger.

chemrox - 29-6-2009 at 15:16

No Sauron had it right. All the (pome) fruit pits contain a certain amount of HCN. Benzaldehyde also smells a bit like cherries to me. BTW Sauron is probably the most knowledgeable member here on essential oils used in liqueurs.

setback - 29-6-2009 at 15:28

Quote: Originally posted by Sauron  
More specifically, benzaldehyde smells like burnt almonds. So does HCN.

Now if you really want to be confused, make some cherry brandy (by fermenting mashed cherries then distilling the resulting wine. Do you know what it will taste like?

Almonds. Burnt almonds. If you want to check this without all the labot buy a bottle of Kirsch (cherry) brandy, the real European stuff not the drug store crap mixed up from extracts. Real Swiss or German Kirsch.

And all makers of eau-du-vie, strong European fruit brandies will tell you that they must build a special cyanide trap into the still, because the pits at the center of most fruit release a lot of cyanide.


While not a liqueur, you ever have authentic kriek (not the sweetened crap)? It's a cherry infused lambic beer, real interesting stuff.

12AX7 - 29-6-2009 at 17:29

Speaking of "benzaldehyde smell", I recently melted a bunch of old acid-core solder. Now, acid flux usually consists of zinc chloride as the active ingredient, with various other organic and inorganic materials depending on how reactive the mix needs to be. This particular flux melted to a tan colored paste. There was some residue leftover in the steel can I melted it all in; a day later, it had abosrbed moisture from the air, resulting in a zinc chloride solution. I rinsed this out into a bucket of water, which happened to have chlorine in it. Soon, I smelled benzaldehyde and traced it to that bucket.

I don't know what they'd be doing with anything benzyl in that flux. The only thing I can think of is, maybe some rosins broke down, yielding something like that. Idunno.

Tim

chemrox - 30-6-2009 at 13:03

@ setback: what is lambic beer?

setback - 30-6-2009 at 13:42

Sorry for the OT:

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

It's very good stuff: dry, tart with some funk, and very refreshing. Very unique.

zajcek01 - 15-7-2009 at 00:30

Benzaldehyde smells like almonds to me, but in small concentrations it is more like cherries.