Benzaldehyde and MEK - TwoDogs Method

[lalalander]

I was performing the aldol condensation between benzaldehyde and MEK by heating with aqueous HCl, then washing to neutral and vacuum distilling.

However, I cannot isolate the aldol product by vacuum distillation because my vacuum pump is broken.

It is easy to make sure that things are going well when I get a black oily liquid when heating, but because my reflux condenser is not efficient enough, HCl gas escapes.

So I stir it with aqueous HCl first at 0 degrees for 6 hours and then at room temperature for 24 hours and wait for the mixture to darken in color. But it doesn't happen. It's only a deep red color.

I cannot crystallize the resulting organic layer in any way.

Can anyone help?

Thanks.

 

[The-Hive]

An old fridge compressor are good for vacuum. You can source them from any junkyard.

 

[lamer]

2 köpek methodu he

 

[AKINCI]

What is the dog method?

 

[Osmosis Vanderwaal]

I think for under $15 i could build a venturi type asperator

 

[Field7]

Steam distillation

 

[lalalander]

Can unsaturated ketone be steam distilled? I didn't know. Thanks.

 

[lamer]

rojin napıo

 

[BayHyde]

When 10 grams of Benzaldehyde + 10 grams of MEK and 7 grams of 30.5% aqueous HCl are mixed for 24 hours at room temperature, I obtain an organic layer.

The reaction should be carried out in an inert reactor, and the mouth of the reactor should be sealed with an inert stopper (such as LDPE, Teflon, glass, etc.).

I wash the organic layer with NaHCO3 solution until it is neutral and put it directly into the freezer. No heating. I filter it using a vacuum cleaner motor. This separates the remaining residual Benzaldehyde and MEK. White crystals remains behind.

When I pour -18 degree methanol on it, I obtain completely snow-white crystals. In my last test, I used 50 grams of Benzaldehyde + 50 grams of MEK and 35 grams of 30.5% aqueous HCl. I obtained 46 grams of snow-white crystals.

Methanol must be cooled in the freezer. Otherwise a lot of crystal will dissolve in the washing step.

I also think you can use ice water when washing, but I haven't tried it yet.

I no longer have any problem with aldol condensation step.

Here is a picture showing the upper organic layer, the lower aqueous layer, and the crystals obtained after freezing, before washing with cold methanol, for anyone is interested;

 

[lalalander]

When 10 grams of Benzaldehyde + 10 grams of MEK and 7 grams of 30.5% aqueous HCl are mixed for 24 hours at room temperature, I obtain an organic layer.

The reaction should be carried out in an inert reactor, and the mouth of the reactor should be sealed with an inert stopper (such as LDPE, Teflon, glass, etc.).

I wash the organic layer with NaHCO3 solution until it is neutral and put it directly into the freezer. No heating. I filter it using a vacuum cleaner motor. This separates the remaining residual Benzaldehyde and MEK. White crystals remains behind.

When I pour -18 degree methanol on it, I obtain completely snow-white crystals. In my last test, I used 50 grams of Benzaldehyde + 50 grams of MEK and 35 grams of 30.5% aqueous HCl. I obtained 46 grams of snow-white crystals.

Methanol must be cooled in the freezer. Otherwise a lot of crystal will dissolve in the washing step.

I also think you can use ice water when washing, but I haven't tried it yet.

I no longer have any problem with aldol condensation step.

Here is a picture showing the upper organic layer, the lower aqueous layer, and the crystals obtained after freezing, before washing with cold methanol, for anyone is interested;

 

[lalalander]

I'm grateful to everyone who approaches my problems with the intention of helping, whether it benefits me or not. I'm just very tired. I'm sorry if my behavior was hurtful to you.

Thanks.

 

[layla]

hello how can i prepare peracetic acid for benzaldehyde and butanone method thank you

 

[HIT MONKEY]

The end result is P2P, right? And how many % purity is it? thank you

 

[lalalander]

No. It is 3-methyl-4-phenyl-3-buten-2-one. It is oxidized to the enol acetate ester of P2P and hydrolyzed to rearrange P2P.

 

[AKINCI]

Is this P2P?

 

[lalalander]

Are you serious? Someone else already asked this, and I already answered. Are you blind or something? It's 3-methyl-4-phenyl-3-buten-2-one.

 

[Newbee]

can anybody provide me receipt to it

• lalalander

 

[lalalander]

When 10 grams of Benzaldehyde + 10 grams of MEK and 7 grams of 30.5% aqueous HCl are mixed for 24 hours at room temperature, I obtain an organic layer.

The reaction should be carried out in an inert reactor, and the mouth of the reactor should be sealed with an inert stopper (such as LDPE, Teflon, glass, etc.).

I wash the organic layer with NaHCO3 solution until it is neutral and put it directly into the freezer. No heating. I filter it using a vacuum cleaner motor. This separates the remaining residual Benzaldehyde and MEK. White crystals remains behind.

When I pour -18 degree methanol on it, I obtain completely snow-white crystals. In my last test, I used 50 grams of Benzaldehyde + 50 grams of MEK and 35 grams of 30.5% aqueous HCl. I obtained 46 grams of snow-white crystals.

Methanol must be cooled in the freezer. Otherwise a lot of crystal will dissolve in the washing step.

I also think you can use ice water when washing, but I haven't tried it yet.

 

[LabPsycho]

The reaction was carried out: 53 g of benzaldehyde + 36 g of MEK + 36 g of hydrochloric acid (0.50 mol reaction). Temperatures: 115°C to 125°C degrees. Time: 4 hours.
The reaction was carried out: 82 g benzaldehyde + 55 g MEK + 55 g hydrochloric acid (0.76 mol reaction). Temperatures: 115°C to 125°C degrees. Time: 7 hours.

Those were washed with brine, pure water and neutralized to pH: 7.

The combined dark brown oil from both reactions was dried for some time with the help of mild heat and acetone, because both had still accumulated a little water at the bottom, and the substance had to be steamed a little cleaner so that the dark oil would eventually become an orange-colored crystal. The rest of the water was sucked out with a measuring syringe. A black colored oil remained.
There was 133.26g of oil (waste without a measuring cup) and it was put in the freezer for 12 hours, during which time everything had crystallized into orange crystals.

 

[LabPsycho]

After those reactions, I made peracetic acid and left 133 g of MPB in (almost neutralized, little "overflow..") peracetic acid at room temp, got 106,3 g of the acetoxy ester. So the yield was ~ 75% (molar). Little dissaponted, but hey, there is some product to be hydrolyzed...

 

[lalalander]

I can't get the peracetic acid and performic acid to work. Any suggestions?

 

[LabPsycho]

But why do you make things so complicated? That I was wondering ...
Just believe you have oxidized the shit, and extract the ester, hydrolyze it.
But now you know, the procedure works. The oxidation needs H2SO4-catalyst.

 

[lalalander]

It's okay. We're all human beings.

---

It would make a lot of sense if I wrote all my tests on a chronological timeline; you'd see that they all have really logical explanations.

When I performed oxidation with pre-prepared peracetic acid, I was left with a crystallized liquid. Since I used a buffering agent, I thought these were sodium acetate crystals.

However, when I didn’t use a buffering agent, I noticed that I obtained crystals with a strong acetic acid smell, and no matter how much I washed them, the smell wouldn’t go away.

These crystals also had a lower melting point than the starting ketone. I never encountered this in an in-situ reaction.

That’s why I thought the crystals were the unreacted aldol product, and since everyone said I should have smelled a "sweet aroma," I assumed the reaction was a failure.

In Böeseken's article, he stated that this ester could form two isomers and give a semi-liquid, semi-solid ester.

The acetic acid smell was due to partial hydrolysis because when the acetoxy ester undergoes hydrolysis, it forms P2P and acetic acid. It took me a while to put all the pieces together.

Although I'm still not entirely sure whether what I obtained is P2P, it should be. I performed a reductive amination, but I’m not keen on using the product without confirming its identity.

It freezes between -15 and -22 degrees, and when I take it out of the freezer, it turns liquid again within a short time.

As you know, aldol products maintain their crystalline form once frozen. This is definitely not the aldol product. But we will see.

 

[AKINCI]

Is this P2P?