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Morgan
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[*] posted on 5-11-2021 at 06:06


Quote: Originally posted by walruslover69  
probably either magnetite which is what makes obsidian black, or carbon powder. can't be certain though


I was wondering if it's a surface coating/impregnation of some sort or possibly some manganese or selenium but I don't know anything about what it might be.Selenium can make a dark red and maybe mixed with another agent make black. Someone probably has a better idea than selenium.

"Heraeus Black Quartz (HBQ®) is a unique black opaque quartz glass composite that benefits from high purity ..,"

"The total level of impurities in HBQ® is <50 ppm, resulting in a bulk purity of >99.995%. Even for the most sensitive leading-edge semiconductor applications HBQ® is a qualified and viable material solution. HBQ® is free of carbon and problem metals like Iron, Titanium, Tungsten, Chrome or Nickel."

"In almost any atmosphere HBQ® can be used at temperatures up to 1300°C safely and reliably."

There's this listing on eBay and I wondered if it used selenium or something else and if the fused quartz tubes were used for heating or what?
"Ruby/red fused quartz tubing, OD 16mm x WT 1.2mm x L 48", 10 pcs"

[Edited on 5-11-2021 by Morgan]
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[*] posted on 5-11-2021 at 13:53


Quote: Originally posted by j_sum1  
But, again, a blue complex has me stumped.


The most Occamite culprit is Cu+2. It's a quite intense blue.




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[*] posted on 7-11-2021 at 10:17


I need a little bit of naphthalene, and at my usual suppliers, its either too much, too costly, or both at the same time.

Now I stumbled upon mothballs, brand "eagle", and they are literally called that.
"Naphthalene balls".
Said to be 99% pure naphthalene somewhere(but not on an MSDS).
Apparently shipped from sri lanka, as seen on ebay.
Now, if thats a 2nd-3rd world product, I have not much doubt about its composition being really mostly just naphthalene.

I still thought I might ask what you think of this?
It looks, probably tastes and feels too, like naphthalene.
It might even sound like naphthalene.
Could it bee naphthalene? :)

Are these old fashioned mothballs(are they even legal to import into the EU, would be the next questions?) a good OTC source of naphthalene?
I don't think I require more than 100 grams at all, and those seem to be a cheap source.
Amazon on the other hand also offers "presto!" brand mothballs.
Also said to be naphthalene based, but I haven't found any MSDS yet.
Neither from the other, "eagle" brand, thats mostly sold on ebay.

For other mothballs though, and it doesn't look to me like they are all pure naphthalene, sometimes they contain nasties such as camphor.

TL;DR: are naphthalene mothballs a good naphthalene source?

Obviously one would think yes, they are, and thats why I ask first.
There might be something obvious I just did not notice.




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[*] posted on 7-11-2021 at 11:06


Here's an sds for Enoz old fashioned mothballs. 99.95% napthalene.

Attachment: ec93188d-b321-4f9e-a9b8-3e3aa9cee264.pdf (271kB)
This file has been downloaded 99 times

I suspect Eagle brand and Seagull brand (a cheap knockoff) are both also pure napthalene.
They both say so on the package.

I see ads for Eagle and Seagull using the word camphor, but the package in the ad says pure napthalene.

Maybe camphor is used as a generic term for mothballs in some parts of the world?
Maybe its a translation problem.

You could always recrystalize from methanol,(EDIT: or etnanol?) or even sublimate to avoid any nasty surprises.

I really doubt there will be any.

I found all these product on Ebay.


[Edited on 7-11-2021 by SWIM]

[Edited on 7-11-2021 by SWIM]

[Edited on 7-11-2021 by SWIM]




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karlos³
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[*] posted on 8-11-2021 at 06:59


Thank you, thats great to hear :)
I will go for the cheaper version, or whose smallest package size contains more.
After all, I definitely want to prepare more than just one substance from it.

At least I will know if there's camphor in it, my nose got pretty sharp now thats 3 years after I stopped smoking, but I would even bet I could smell a tiny hint camphor in the odour of naphthalene :)




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[*] posted on 8-11-2021 at 20:26


Have about .5l chrome VI waste and I don't want to use the last of my bisulfite to reduce it to Chrome III. Suggestions?



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[*] posted on 9-11-2021 at 01:29


Quote: Originally posted by arkoma  
Have about .5l chrome VI waste and I don't want to use the last of my bisulfite to reduce it to Chrome III. Suggestions?


Any chance you can precipitate ammonium dichromate? What else is in the waste?
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[*] posted on 9-11-2021 at 07:33


Quote: Originally posted by arkoma  
Have about .5l chrome VI waste and I don't want to use the last of my bisulfite to reduce it to Chrome III. Suggestions?


Bubbling SO2 through it should work, but you'd have to set up a gas generator.

Or, dry it out, mix with aluminum powder, and ignite!




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[*] posted on 9-11-2021 at 07:36


Shouldn't Cr-6+ be reducible with say, metallic iron? Just to make it simple and non-toxic.
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[*] posted on 13-12-2021 at 17:23


When preforming a fractional distillation with a column. How will the separation compare when distilling under vacuum vs at atmospheric pressure? Is one method better at fractionating compounds?
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[*] posted on 13-12-2021 at 18:21


Quote: Originally posted by Jome  
Shouldn't Cr-6+ be reducible with say, metallic iron? Just to make it simple and non-toxic.

Yes, thats actually the standard way how you should treat chromate waste.
I do it like this, all the chromate waste gets reduced with iron powder.




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[*] posted on 14-12-2021 at 00:54


Quote: Originally posted by arkoma  
Have about .5l chrome VI waste and I don't want to use the last of my bisulfite to reduce it to Chrome III. Suggestions?

You can also get rid of it by adding acidified aqueous ethanol to it (e.g. a mix, containing 10% HCl and 20% ethanol). That reaction is fairly fast. Gently heating speeds it up even more. Wait until your solution is green.

Use a fine whiskey for a good reduction :P




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[*] posted on 16-12-2021 at 06:49


pretty much any easily oxidized compound will work with dilute solutions of chromium (vi) compounds.
just add the compound and slowly acidify.
glycerin, isopropanol, methanol, propylene glycol, ethylene glycol, even table sugar.
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[*] posted on 24-1-2022 at 05:18


Guys, I have a suspicion, tetrachloroethene can be dehydrochlorinated simply by calcium hydroxide, right?

Now if one would run an SN2 reaction with an amine, diethylamine in that case(but I had over a half year ago two trials with ethyl- and methylamine, same outcome, but I thought its been the fault of the ketones and not of the solvent....), in tetrachloroethene....
Maybe even with some additional heating at the end?
It was a bromoketone the amine was substituted with, by the way, so a tertiary aminoketone in the end and those are pretty stable.
I distilled some diethylamine off too, before starting the workup.

So, my question, could my solvent have eaten up the amine, prevented a well succeeding reaction?
Sorry, proper terms: could primary or secondary amines, in combination with moderate heating, also dehydrochlorinate tetrachlorethene to TCE as could calcium hydroxide?
Makes sense to me.
Way too much sense actually.

I will carefully pay attention when I redistill that stuff.
Because if this had happened(I did not pay attention when I redistilled it after the last use, because as said, suspected the self made ketones and not the solvent), it should be observeable easily by a fraction of TCE in the "perc".




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[*] posted on 24-1-2022 at 13:12


Cr6+ is reduced by ascorbic acid solution, it is a standard practice to render Cr6+ spills harmless

I prepped some Pd(NH3)2Cl2 it settled out of the solution however the remaining ~1litre (pH ~2 with excess of HCl) on top of it was still yellow, as an attempt to reduce its volume to ~200ml I tried to evaporate it at ~60°C, the solution became dark in the process and Pd(NH3)2Cl2 precipitate disappeared, some of it changed color from yellow to orange. What is this dark very water soluble compound? Addition of excess NH4OH gave the pink precipitate as usual. Heating the pink ppt (pH~14) redissolved the palladium complex giving blue color without residue.
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[*] posted on 25-1-2022 at 12:22


In a reaction involving the ester reaction between PABA and an aminol will there be any reaction with the amine on the benzene ring....during a fisher esterification....some insight would be appreciated. ....the target compound is dimethocaine.......solo

[Edited on 26-1-2022 by solo]




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[*] posted on 27-1-2022 at 01:52


Quote: Originally posted by solo  
In a reaction involving the ester reaction between PABA and an aminol will there be any reaction with the amine on the benzene ring....during a fisher esterification....some insight would be appreciated. ....the target compound is dimethocaine.......solo

[Edited on 26-1-2022 by solo]


......ok, so the paba is a result of a combination of a strong addition and a strong withdrawing groups, an electrophilic aromatic addition with the amine directing to the ortho para position, .....modifying the withdrawing component with a Lewis acid to make an ester with an aminol.....to me it seems some reaction may occurr with the two available hydro gens on the amine , hence some protection ,maybe a Boc or acylation , or maybe nothing will happen and esterification will occurr without any hitch ( wishful thinking)... Any thoughts?.....solo




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[*] posted on 27-1-2022 at 07:36


I believe that an amine will usually be inert under Fischer esterification conditions because it is protonated. So it should work fine.



[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 27-1-2022 at 14:47


Quote: Originally posted by clearly_not_atara  
I believe that an amine will usually be inert under Fischer esterification conditions because it is protonated. So it should work fine.



........thank you, on the other hand instead of PABA benzocaine is used , hence a transterification under basic condition using sodium methoxide, will the amine have to be protected , say an acid chloride to an amide, will the transterification effect the carbonyl group on the amide , or is there another way to protect it ( if it's needed) so the transterification goes smoothly to avoid those possible events ,....thanks again for your time ......solo




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[*] posted on 28-1-2022 at 19:43


Solo,

Since your synthesis route involves a transesterification you do not need to protect the PABA amino group. Amine protection would only make the process more complicated since you would have to remove the protective group without losing the new ester group. Also keep in mind that protection of the amino group via acylation will create an acidic NH (like an imide) which will consume base used in transesterification.

Your target is very interesting. It looks like no one has published an alternative synthesis since the original by Mannich.

AvB
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[*] posted on 29-1-2022 at 09:22


Thank you for your evaluation , I will stay on without concern with the amine interfering with the transterification....will post results.....solo



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[*] posted on 31-1-2022 at 19:30


......this was helpfull.

The Synthesis of 2,2-Dimethyl-3-(4-morpholinyl)-l-propanol and Analogous Amino Alcohols by the Mannich and Crossed Cannizzaro Reactions
LEE C. CHENEY
American Chemical Society
73(2), 685�686.
doi:10.1021/ja01146a053

Summary
The crossed Cannizzaro reaction has been found
to constitute an excellent method for the reduction
of a, a-disubstituted amino aldehydes.
A unit process involving a combination of the
Mannich and crossed Cannizzaro reactions has been
described which affords a direct and practical
synthesis for a variety of 2,2-disubstituted amino
alcohols analogous in constitution to 2,2-dimethyl-
3-(4-morpholinyl)-l-propanol.

https://pubs.acs.org.sci-hub.se/doi/10.1021/ja01146a053
[Edited on 1-2-2022 by solo]

[Edited on 1-2-2022 by solo]




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[*] posted on 6-2-2022 at 13:42


On a similar reaction 4-aminobenzophenone , once chlorinated with TCCA the 3,5 positons get chlorinated as a result of the activating position ortho para by the amine and the deactivation and of the carbonyl group .....now the ketone needs to be brominated hence my question ...will the amine be affected the condensation and brominate with Br in ChCl3......Ooh,.... target compound is Clenbuterol.....solo



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[*] posted on 7-2-2022 at 14:41


...had a thought, perhaps the most direct way is to brominate acetone than add the ter- butylamine, then again brominate the ketone and do a FC in toluene using ZnO , it will go to the para position relative to the amine since the amine is strong activating and directs ortho para. but because of the bulkyness of of the alkane it will avoid steric interference and place it salf para -relative to the amine.......then reduce with NaBH4 /methanol to get the desired compound base.......solo



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[*] posted on 7-2-2022 at 20:34


Solo,

I do not believe that your "...had a thought" route stands much of a chance. Too many things can go haywire.

There are two "standard" syntheses of your target clenbuterol that I have reference to. Both use a nitro group as a "protected" amino group while other chemistry is carried out.

Synthesis 1.

p-Nitroacetophenone is brominated on the methyl group. t-Butylamine reacts with the bromoketone to provide the t-butylaminoacetophenone intermediate. The nitro group is then selectively reduced (vs the ketone) with RaNi. The amino compound then is chlorinated with Cl2 in HOAc followed by borohydride reduction of the ketone to clenbuterol.

Synthesis 2.

2-t-Butylamino-1-phenylethanol is nitrated (HNO3). The hydroxy and amino functions are then protected as an oxazolone analog by reaction with phosgene. The resulting nitro compound was reduced to the amine and chlorinated as in Synthesis 1. Treatment with KOH removed the oxazolone group to give clenbuterol.

If I were to attempt to make clenbuterol (assuming I could not easily get any of the other starting materials) I would start with 1-phenylethanol (styryl alcohol) which is easily obtained as a fragrance chemical. Nitration should give the p-nitro derivative as the predominant isomer. Oxidation of the p-nitro alcohol will give the p-nitroacetophenone for Synthesis 1. This route has the nitration at the beginning of the synthesis so that isomer problems related to nitration do not arise late in the synthesis costing valuable material.

Alternatively, easily available acetophenone could also be a starting material. Bromination of the methyl group followed by reaction with t-butylamine then reduction of the ketone gives the starting material for Synthesis 2. Phosgene used in Synthesis 2 could be replaced by carbonyldiimidazole (CDI). The nitration late in the synthesis after manipulating acetophenone seems to me not to be so desirable.

I hope that what I have written is clear and helpful.

AvB

[Edited on 8-2-2022 by AvBaeyer]
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