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Author Topic: Short Questions Thread  (Read 10826 times)

Methyl Man

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Re: Short Questions Thread
« Reply #940 on: July 16, 2011, 04:56:36 PM »
Quote from: Enkidu on July 15, 2011, 03:16:22 AM
Quote from: Methyl Man on July 15, 2011, 02:31:42 AM
If so, see what solvent is recommended and the type of chromatography plate they use.[/i]

The solvent is called the eluent, and the choice of eluent depends on the analyte (or whatever they call it in preparative chromatography).

Sorry, I should have specified. The hypothetical material being analyzed would be the extraction of MDMA freebase with toluene from a matrix that included aluminum, Hg/HgCl2, NaOH, MDP2P, methylamine, etc. Hypothetically speaking, of course.

I told him I would ask you all about this, but I also told him that I didn't think that chromatographic analysis was necessary in such a hypothetical situation since the proper washing of such an extract (along with good extraction technique) has been shown by experience to be sufficient to ensure purity.
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Enkidu

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Re: Short Questions Thread
« Reply #941 on: July 16, 2011, 10:34:31 PM »
^ I'm too lazy to look up the forensic analysis papers now (they're on the boards or in the rhodium archives somewhere), but they'll show you the impurities that come from the reduction of the imine. There are more impurities possible if you run a one pot ketone + amine --> desired amine.

RoidRage

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Re: Short Questions Thread
« Reply #942 on: July 17, 2011, 10:20:37 PM »
Quote from: Enkidu on July 16, 2011, 10:34:31 PM
^ I'm too lazy to look up the forensic analysis papers now (they're on the boards or in the rhodium archives somewhere), but they'll show you the impurities that come from the reduction of the imine. There are more impurities possible if you run a one pot ketone + amine --> desired amine.

Is this the paper you're talking about?

Enkidu

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Re: Elemicin from Gallic Acid
« Reply #943 on: July 22, 2011, 02:55:30 AM »
Quote from: Bardo on July 15, 2011, 04:15:09 PM
"Studies on Elemicin Synthesis" by Dorothy Huang Hains published by McNeese State University in 1976.

>>DOWNLOAD<<

reDEEMed

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Re: Short Questions Thread
« Reply #944 on: July 22, 2011, 08:31:45 PM »
Besides thionyl chloride, are there alternate methods to prepare acyl chlorides from carboxylic acids? By alternate I mean more accessible.
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Enkidu

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Re: Short Questions Thread
« Reply #945 on: July 22, 2011, 09:28:16 PM »
S2Br2, prepared by adding bromine to sulfur.

reDEEMed

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Re: Short Questions Thread
« Reply #946 on: July 23, 2011, 03:43:29 AM »
Very helpful, thank you.

I'm going to make one assumption here. Looking at bromine prices I see that pure bromine is very cost prohibitive unless the target compound is gold. I will assume that bromine tablets from the pool and spa supply will somehow suffice. It will be quite sometime before I would want to try this. Right now I'm just thinking and dreaming about what could be possible with a fully stocked chemical closet.

Thanks again.
"Ego is a structure that is erected by a neurotic individual who is a member of a neurotic culture against the facts of the matter. And culture, which we put on like an overcoat, is the collectivized consensus about what sort of neurotic behaviors are acceptable."
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Terror

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Re: Short Questions Thread
« Reply #947 on: July 25, 2011, 04:21:27 AM »
Vacuum question:

I am well confused here..

Looking at an Edwards EB3A vacuum pump / compressor. There doesn't seem to be any good information in the net but I have seen the following couple of statements:

"Vacuum - 100 Torr"
"Sucks down to -0.7 Bar"
"I was able to connect it to my vacuum gauge and it pulls and hold 29 in hg easily which is pretty much 99% vacuum"

Can anyone tell me if this pump is good for freebase distillation? The 29" hg statement leads me to think so but, maybe not? 100 Torr = 3.93" hg.. correct me if I am wrong here??
« Last Edit: July 25, 2011, 04:22:59 AM by Terror »
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akcom

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Re: Short Questions Thread
« Reply #948 on: July 25, 2011, 04:56:33 AM »
Thats fine for distillation

akcom

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Re: Short Questions Thread
« Reply #949 on: July 25, 2011, 01:44:14 PM »
has anyone ever had their Al/Hg nitromethane reaction mixture turn a rusty orange color after flooding with NaOH?

antibody2

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Re: Short Questions Thread
« Reply #950 on: July 25, 2011, 05:12:38 PM »
@ Akcom
No. It always turns grey and the organic layer is usually a hazy white/clear. That's if the the and nitromethane was pure and ketone was distilled prior to reduction/amination.

lugh

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Re: Short Questions Thread
« Reply #951 on: July 25, 2011, 08:02:58 PM »
Quote
has anyone ever had their Al/Hg nitromethane reaction mixture turn a rusty orange color after flooding with NaOH?

Impure ketone has been known to cause such colors  8)
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Tsathoggua

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Re: Short Questions Thread
« Reply #952 on: July 25, 2011, 08:06:21 PM »
NaOH, MeNO2...the hell with that!
Nomen mihi Legio est, quia multi sumus

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akcom

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Re: Short Questions Thread
« Reply #953 on: July 25, 2011, 09:37:42 PM »
The ketone was distilled twice, but it was allowed to sit at RT for a long period of time and acquired a definite 'neon yellow' color.  Thanks for the info guys

lugh

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Re: Short Questions Thread
« Reply #954 on: July 25, 2011, 11:10:05 PM »
A short column makes it possible to purify ketone better  8)
Chemistry is our Covalent Bond

akcom

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Re: Short Questions Thread
« Reply #955 on: July 25, 2011, 11:51:22 PM »
I've been putting off getting a 150mm column for a while now, I guess I should get on that.  Am I missing something obvious or is it near impossible to find anything shorter?

Enkidu

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Re: Short Questions Thread
« Reply #956 on: July 30, 2011, 12:09:51 AM »
IIRC, there's an orgsyn ref for the halohydrination of isosafrole or a similar substrate. Does anyone have it?

reDEEMed

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Re: Short Questions Thread
« Reply #957 on: July 30, 2011, 01:16:08 AM »
Let's say someone had some NaOH+NaClO+H2O in a sealed jar in the fridge/freezer for a week, never got above 4c. Could that be used in a Hoffman reaction or should it be made again?
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devongrrl

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2-chloro benzaldehyde
« Reply #958 on: July 31, 2011, 12:20:59 PM »

I've been trying to come up with a forward synthetic route to 2-chloro benzaldehyde by looking at it from the
disconnection approach but not getting very far.

Does any one have any tips ? I tried UTFSE but I haven't found any synths , just uses.

reDEEMed

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Re: Short Questions Thread
« Reply #959 on: August 08, 2011, 01:36:56 PM »
What are some reactions that will replace an existing group with a carbonyl group? I've been reading pdfs and searching for almost 12 hours straight and I'm starting to think it's just not possible.
"Ego is a structure that is erected by a neurotic individual who is a member of a neurotic culture against the facts of the matter. And culture, which we put on like an overcoat, is the collectivized consensus about what sort of neurotic behaviors are acceptable."
— Terence McKenna
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