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Author: Subject: The Short Questions Thread (4)
redshield5
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[*] posted on 8-4-2023 at 18:12


Quote: Originally posted by Variscite  
I bought some Clean Shot H2SO4 drain cleaner the other day, it says it contains inhibitors in it. It has a clear purple color to it. I was wondering if anyone knew what these inhibitors were? Ive done some research on this, but havent found much, some say they are flourinated. I would also like to know the purity of this stuff, ive read about suspected Se impurities (eek)! What could the applications and constraints be of this H2SO4 vs say technical grade?

<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: added to subject field]

[Edited on 7/12/13 by bfesser]


Hey Variscite, I've gotten so used to reddit lately that I kinda forgot how old school forums work lol. But hopefully you can see my reply as a notification.

For what it's worth (and I've never tried this): My mentor (and I consider him a very reliable, skilled chemist), once described to me a method to clean H2SO4 from liquid drain cleaners.
He told me to add a few drops of 3% H2O2 and then gently simmer/boil until the solution starts fuming and turns clear, then remove from heat.

Not sure how well it works or if there are any dangerous "side effects" of this procedure, so PLEASE be careful and DO YOUR OWN RESEARCH before simply taking me at my word and carelessly boiling strong acids. Hope it helps you!

[Edited on 9-4-2023 by redshield5]




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[*] posted on 8-4-2023 at 19:16


You just replied to a post from 10 years ago by a member who hasn’t been active in 10 years.



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[*] posted on 10-4-2023 at 16:10



If starting a 3 phase motor (about 20kW) which is on a centrifugal pump, how big a generator do you need (I am going to run the 3 phase motor from a 3 phase generator). The power going into the generator is not an issue (PTO driven).
Reading on the net (AFAICS) you seem to need a generator that is much bigger than the motor.
Asking a generator seller I was told that the generator needs to be about 4 times bigger. A 20kW motor needes an 80kW generator.
Seems very big.
I have no control gear on the motor so no gentle start etc. I can arrange to have no water in the pump at startup so that may help.

I was hopeing to buy a 30kW generator and use that. It it big enough. The geneator is an old type (Brush, makers name) so the rating would be generous (I think).

TIA,
Yob

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[*] posted on 10-4-2023 at 23:50




https://www.engineeringtoolbox.com/amp/locked-rotor-code-d_9...

A picture of the pump plate would be helpfull. Most large 3p motors have a "class" which tells you about what conditions the motor can withstand, and a "code" to calculate the startup current, so circuit sizing, thermal overloads, etc can be calculated.

Assuming 480v code "d", the math would look like the following
Full Load Amps
Power / voltes = amps
Watts ÷ (Voltage * √3) = Amps
20000 ÷ 480 * 1.732 = 24.22

Starting current
FLA × code_minimium = Lock Rotor Amps minimum
FLA × code_maximum = Lock Rotor Amps maximum
24.22 × 4 = 96.90 amps
24.22 × 4.49 = 108.77 amps.

Back to watts(KVA)
108.77 × 480 × √3 = 89800 watts or 90 KVA peek power

So now we get into the accounts screwing things up, selling you something that is not as described.
Most generators are advertised as their peek power output.
For example small generator usually can only continuously deliver 60% of the power they are advertised as. You have to read the literature and find the peek power and continuous power

Please do not run your pump dry. every time you do a gasket crys

[Edited on 11-4-2023 by Rainwater]




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[*] posted on 11-4-2023 at 11:14


Quote: Originally posted by Texium  
Assuming it doesn’t contain other volatile components that are problematic, that sounds good. Depending on what range of alkanes are in it you may even be able to fractionate it into portions with different boiling ranges. Also look for “non-flammable” brake parts cleaner. It is usually pure tetrachloroethylene. It seems to be getting more difficult to find, though.


I have been fractionally distilling the above and I'm getting two main fractions, one at ~50 deg C and another at around 70 deg C.

I am confused which alkane or isoalkane these could be as the boiling pointds don't coincide very well.

Also the can states less that 5% n-hexane so i'm ruling that out mostly.

[Edited on 11-4-2023 by Chemgineer]
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[*] posted on 11-4-2023 at 11:29


There could be a larger portion of mixed hexane isomers that would explain the 70° fraction. SDS aren’t always the most reliable and exhaustive things out there. 50° is kinda weird though since that’s between pentane and hexane. Only thing I can think of that’s close is cyclopentane.

What do these fractions smell like?




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[*] posted on 11-4-2023 at 11:51


Quote: Originally posted by Texium  
There could be a larger portion of mixed hexane isomers that would explain the 70° fraction. SDS aren’t always the most reliable and exhaustive things out there. 50° is kinda weird though since that’s between pentane and hexane. Only thing I can think of that’s close is cyclopentane.

What do these fractions smell like?


You could be right with the mixed isomers, I have a bottle of that from a chem supplier and it smells very similar, not strong smelling really though.

The 50 deg C fraction has a slightly stronger smell, sort of reminds me of turpentine.
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[*] posted on 12-4-2023 at 08:34


Doesn't cyclopentane easily form a clathrate with water? Eg:

https://pubs.acs.org/doi/full/10.1021/ie800949k

Maybe you could try this with the 50 C fraction. The clathrates are of interest in water purification, but they might also be useful for purifying the cyclopentane itself.




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 23-4-2023 at 07:02


....unable to find physical properties of 2-(Tert-butylamino)-1-phenylethanone. I will do the Hinsburg Reaction check for secondary amines .....have been reacting 2-bromo acetophenone with tert-butylamine .....solo



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[*] posted on 23-4-2023 at 12:37


Quote: Originally posted by yobbo II  

If starting a 3 phase motor (about 20kW) which is on a centrifugal pump, how big a generator do you need (I am going to run the 3 phase motor from a 3 phase generator). The power going into the generator is not an issue (PTO driven).
Reading on the net (AFAICS) you seem to need a generator that is much bigger than the motor.
Asking a generator seller I was told that the generator needs to be about 4 times bigger. A 20kW motor needes an 80kW generator.
Seems very big.
I have no control gear on the motor so no gentle start etc. I can arrange to have no water in the pump at startup so that may help.

I was hopeing to buy a 30kW generator and use that. It it big enough. The geneator is an old type (Brush, makers name) so the rating would be generous (I think).

TIA,
Yob



Yes, there's a huge starting current with such inductive loads. Many times higher than the normal operating current.
I don't know if your motor is connected as star or delta. But for starting it should be started in star connection (lower coil voltage) and for a higher torque this may be switched to delta afterwards. There are special switches for this.
In star the current and stress to the power source and motor coils will be lower.

Of course the generator should withstand overloading for a short time because in the starting process an electric motor is basically overloaded too. The problem here is overheating or it might even stall the engine. So the engine power might pose the next problem.
What you could do is to connect something in series, maybe three smaller single phase consumers to each phase to increase the overall resistance and limit power draw. It's just a bit difficult with a 20kW beast. In any case the generator should have a significantly bigger continuous power rating than the motor. I'd say at least 2 times bigger but its difficult to say. 4 times bigger sounds reasonable.

But with such a rotary pump it should be no problem to run it dry for a short time.
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[*] posted on 28-4-2023 at 04:11
Volatility of sodium dichromate


I have attempted to produce my own sodium dichromate by fusing pottery grade chromium oxide with sodium nitrate. The product was mixed with water and filtered resulting in a deep red-orange solution. This was boiled down and is now sitting in a vacuum desiccator with a dish of concentrated sulfuric acid. It is now nearly dry.

Two observations have confused me.

1. The sulfuric acid has taken on an orange colour. Evidently the dichromate is somewhat volatile and is absorbing into the acid. I did not expect this. Or maybe I am interpreting the situation incorrectly.

2. The crystals as they dry have become quite yellow -- more like a chromate than dichromate. Again this is unexpected.

Can someone help me understand what is occurring here?
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[*] posted on 28-4-2023 at 07:27


Is it possible that you're getting Na2Cr2O7 <==> Na2CrO4 + CrO3?



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[*] posted on 24-5-2023 at 15:00


...need help naming this , PhCH (OMe)CH,CI...i can't find its physical properties under my naming it .....2-chloro-1-methoxy phenylethane....solo



…….just found it…..
(2-Chloro-1-Methoxyethyl)Benzene. CAS No.: 3898-26-8

[Edited on 25-5-2023 by solo]




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[*] posted on 25-5-2023 at 02:16


J_sum, that looks like you have some CrO3 in your product. Really strange result, CrO3 is usually formed in extremely acidic environment.
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[*] posted on 25-5-2023 at 09:58


J_sum1:
Perhaps if the "drying acid" was to be mostly neutralized and a reductant like ascorbic acid were to be added, you'd see if it turns green which would indicate unpleasant chromates flying around...

If some of the nitrate decomposed to oxides, It'd go alkaline and therefore yellow but that doesn't explain why it went reddish orange when in solution, as if it it is dichromates. I've done the experiment with NaOH in addition to nitrate and Cr2O3, and it turned lime-yellow.
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[*] posted on 25-5-2023 at 19:06


It is still sitting there. I have not pulled a vacuum on it for a while. The solid material is a lighter orange than when I put it in. The sulfuric acid is dark orange: almost tarry-looking.

When I get around to it, I can use the crystals as an oxidant. I am assuming that it is a mixture of sodium chromate and sodium dichromate. I can bottle up the coloured acid which I assume contains chromic acid. It will be good for cleaning glassware.

Nothing wasted.


The surprise is the volatility. I was just not expecting any chromium compounds to migrate.
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[*] posted on 4-6-2023 at 06:13
Post about strange blue liquid


Hi!

Some time ago someone on this forum posted report on some strange blue liquid, which climbed on walls of the beaker. It was something organic, probably something nitrite related. I searched for it quite a long time in the forum engine and on Google, but I couldn't find it. I am not glad that I post this stupid question, but doesn't somebody here remember this post? It was really interesting, I never saw compound like that before.
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[*] posted on 4-6-2023 at 06:44


Glycine dizotization in HCl - blue nitroso product?



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[*] posted on 4-6-2023 at 07:24


Thanks! That's exactly it!
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[*] posted on 5-6-2023 at 10:00


...need help in method to aminate 2-Chloro-1-phenylethanol with tert butylamine...I thought of using DCM with a short time reflux , since 2-Chloro-1-phenylethanol is soluble in DCM and so is tert butylamine....to the target molecule 2-(tert-butylamino)-1-phenylethanol however not sure.......solo

[Edited on 5-6-2023 by solo]




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[*] posted on 6-7-2023 at 05:08
A quick question


Hi there. Can a diprotonated base for example piperazine be protonated with 2 different acids ? For example piperazine mononitrate monoperchlorate by (reacting piperazine nitrate with HCLO4) ?

Also will a diprotonated salt go monoprotonated when its base will be added or it will stay like this, for example dissolving an equal molarity of piperazine dihydrochloride and piperazine freebase will cause all piperazine turn to monochloride or there will only be there as a solution (dichloride and freebase stay as it is)

Thanks

[Edited on 6-7-2023 by underground]
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[*] posted on 10-8-2023 at 15:13


In Ignition!, John Clark mentions a short-lived project which investigated dimethyl mercury as a rocket fuel :o

But there's a part that I don't understand:

Quote:
I thought that it would be an excellent idea to have somebody else make the compound for me. So I phoned Rochester, and asked my contact man at Eastman Kodak if they would make a hundred pounds of dimethyl mercury and ship it to NARTS. I heard a horrified gasp, and then a tightly controlled voice (I could hear the grinding of teeth beneath the words) informed me that if they were silly enough to synthesize that much dimethyl mercury, they would, in the process fog every square inch of photographic film in Rochester, and that, thank you just the same, Eastman was not interested.


Why would mass-producing dimethylmercury damage film?

(interesting, tangentially related: https://orau.org/health-physics-museum/collection/nuclear-we... )




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[*] posted on 10-8-2023 at 19:56


100 pages, might be time to start a new thread maybe?
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[*] posted on 10-8-2023 at 20:17


Quote: Originally posted by underground  
Hi there. Can a diprotonated base for example piperazine be protonated with 2 different acids ? For example piperazine mononitrate monoperchlorate by (reacting piperazine nitrate with HCLO4) ?

Also will a diprotonated salt go monoprotonated when its base will be added or it will stay like this, for example dissolving an equal molarity of piperazine dihydrochloride and piperazine freebase will cause all piperazine turn to monochloride or there will only be there as a solution (dichloride and freebase stay as it is)

Thanks

[Edited on 6-7-2023 by underground]


It's possible to form a double salt like that, but only if the double salt is less soluble than either of the regular salts. I know of one example of a complex chromium ion that forms a salt with one chloride and one nitrate. I'm not sure how one would predict the solubilities of these salts.




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[*] posted on 20-8-2023 at 07:30
Ethyl chloride production risk


I am making p-aminophenol by the hydrolysis of acetominophen following the beginning of the procedure in this paper.

Quote:

Reaction in aqueous medium. A suspension of the correspond-
ing acetanilide 2 (4.2 mmol) in hydrochloric acid (3M, 15 mL)
and methanol (5 mL) was heated to reflux until the solid was
completely dissolved (approximately 5 h).



I am using ethanol instead of methanol.
Is there a risk of producing ethyl chloride during the reaction ?

[Edited on 21-8-2023 by andyloris]




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