Im not sure how DMT orientated but i guess its the right place for it.
I wanted a place to ask a few questions on organic chemistry.

What is an Alkanal? The answer i got was, an alkanal is an aliphatic aldehyde.
So aliphatics are compounds made up with carbon and hydrogen.

Aliphatic:


So an alkanal being an aliphatic aldehyde... Is a compound consisting of carbon atoms bonded to hydrogen, with a single oxygen double bonded to one of the carbons?

Right?

But what of the name alkanal? This suggests a hydroxyl group also. Is that right?



Secondly, If the above is true then an aliphatic compound would have R used in a structural diagram and formula.
So is carboxylic acid also aliphatic due to the R on the oxygen?
See THIS picture.

Yes, an alkanal is an aliphatic hydrocarbon (a chain of carbons all attached to one another by single bonds and saturated with hydrogens), with an oxygen double-bonded to one of the carbons... specifically a terminal carbon (if it were doublebonded to a carbon in the middle of the chain instead, then it would be a ketone instead of an aldehyde, and you'd call it an alkanone).

The name comes from alkane (an aliphatic hydrocarbon) plus -al (the suffix that denotes an aldehyde group)

Alkanal does not imply the presence of a hydroxyl group. That would make the compound an alcohol or carboxylic acid of some type, and the term "alkanal" would imply that the aldehyde is the only functional group present.

Are you sure that you can call an alkanal a hydrocarbon? I'm used to hearing the term hydrocarbon used to refer to compounds that contain only carbon and hydrogen, with no heteroatoms. Also, I'm used to hearing "aliphatic" mean "not aromatic," but it doesn't imply that there aren't any unsaturations, whether they be from rings or from double/triple bonds.

Whether or not a carboxylic acid is aliphatic would be determined by the R group. If R is an alkyl group, then sure. But if there's any aromatic constituent, like a phenyl ring, then it isn't aliphatic.

why not? does it not have a hydrocarbon moeity?
the alkyl moeity makes it a hydrocarbon, not the functional side-group.
fatty acids are technically (aliphatic) hydrocarbons with a carboxylic group.

So if one was given several examples of Alkanal structures (some false and some true), what would i be looking for? Diagnostically, point by point.

Samadhi is saying its not aliphatic, does not have a hydroxyl group and has more then one functional group.
Its not a hydrocarbon? That makes sense. What with the oxygen and all.

But we are all agreed on the double bonded oxygen.

that's a carbonyl.

and alkanals have aliphatic moeities, hence the alkan-prefix. it is a hydrocarbon with an aldehyde group.

an example is butyraldehyde (butanal). the butane group represents the aliphatic 'tail'

Err, what I mean to say is this. The word "alkanal" doesn't have anything to do with hydroxyl groups. "Alkanal" means that you have an alkane chain where a terminal carbon has a carbonyl group, and also a single hydrogen. If you want to think of this in terms of functional groups, then that means you have an alkyl group attached to an aldehyde moiety.

And alkanals are aliphatic. They don't contain any aromatic constituents, so they're aliphatic.

Benzyme, I think I see what you mean. So "hydrocarbon" is referring to the nature of a molecule being constructed from a carbon/hydrogen skeleton, and it doesn't specifically exclude heteroatoms from being anywhere on the molecule?

exactly.

i know that hydrocarbons make one think of alkanes/alkenes
but technically, all organic molecules are hydrocarbons/have hydrocarbon skeletons. the functional side groups are just a part of the whole.

Many thanks! There will be more...

I just figured id use this thread to ask... Id like to get my hands dirty doing some organic chemistry. But seeing as im not in class right now, can anyone recommend some interesting (legal) experiments/synths/fun/extractions.

Try extracting salicylic acid and try to acetylate it to acetylsalicylic acid.

I've never done it but it sounds fun and reasonably challenging.

Oh... aspirin, neat! Anything else? I was thinking about capsicum extraction too.

Bumping this in the hope some folks suggest some fun experiments!

Make beer - and possibly distil it, just for fun. It entails a combination of techniques that involves:

1) Gelatinisation and enzymatic hydrolysis of starch to simpler sugars
2) (0ptional) enzymatic hydrolysis of proteins to aminoacids and oligopeptides)
3) (optional) enzymatic hydrolysis of cell walls to simpler sugars
4) Extraction of sugars + peptides
5) AVOID extraction of tannins
6) Thermal-assisted chemical conversion and isomerisation of alpha acids during wort boiling and hopping;
7) differential dissolution of flavour and aroma compounds during beer preparation
8 ) (optional) extraction and isomerisation of alpha acids and other essential oils from hops, just for the fun of it
9) employ fining agents to precipitate tannins, proteins etc.
10) preparation of yeast, fermentation etc etc.
11) assessment of yeast metabolites in the brew; ethanol, ethyl acetate, amyl acetate, ethyl butyrate, endless list.
12) (optional) distillation.

The whole process has a bit of everything; some chemistry, some physics, some microbiology, some molecular biology. Will sure keep you busy for a long time.