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Author: Subject: The Short Questions Thread (4)
CharlieA
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Just a WAG (as opposed to a SWAG): could this be some kind of device to deliver 10 mL of a reagent from some kind of reservoir?
B(a)P
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Some time ago I purchased a cheap condenser and it came with an addition funnel. I used the addition funnel for the first time today and it was almost impossible to get a constant drip rate. Can I replace the tap to get something usable, any tips for getting crappy taps to perform or do I just forget it?
clearly_not_atara
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 Quote: Originally posted by S.C. Wack The only time anyone does it (edit: should do it) cold is when they are trying to do it without glassware.

For the reaction this is true, but in order to achieve the best phase separation at workup you want the solution to be just barely above freezing IIRC

[Edited on 04-20-1969 by clearly_not_atara]
paulll
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Has anybody ever heard of such a thing as a spring-loaded flask clamp? With how handy it would be for receiving flasks it seems to be a thing that should exist and yet I don't see any anywhere.
karlos³
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 Quote: Originally posted by paulll Has anybody ever heard of such a thing as a spring-loaded flask clamp? With how handy it would be for receiving flasks it seems to be a thing that should exist and yet I don't see any anywhere.

Could you draw one, just a bad sketch to get the idea?
I'm not sure how that should look like.

I hope not like that: https://www.sigmaaldrich.com/content/dam/sigma-aldrich/produ...
Because that would mean they stole and produced your idea, and that in merely hours!
Those capitalist pigs, no respect on your intellectual property!

But seriously, like that?
Because initially I imagined a clamp to hold the receiving flask connected with the vacuum adapter(or cow) or such.
Only that I can't picture how such a thing would look like spring-loaded, which is why I was asking for a sketch of it.
And promised, not to steal the idea and sell it to sigma or whoever bids most, you have my hobby chemist word of honor on that!
paulll
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Mood: It's fine. Really.

Notwithstanding the fact that I can't draw with or without a computer... something like this. I'm thinking, e.g., for the receiving flask in a distillation rig - or any other flask that you'd want to change out mid-experiment.
So instead of tightening a thumbscrew to apply pressure to the piece, you'd be unscrewing it to release spring tension onto it, to hold it in place. The flask could then be removed and replaced by squeezing the other end of the clamp scissors-style. If that makes sense lol

[Edited on 14-9-2020 by paulll]
Morgan
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Does anyone know a company that makes these cylindrical volumetric flasks?

https://i.ebayimg.com/images/g/QqkAAOSwg35atCrz/s-l1600.jpg
https://i.ebayimg.com/images/g/GLsAAOSwuHZatCr0/s-l1600.jpg
Antigua
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 Quote: Originally posted by Morgan Does anyone know a company that makes these cylindrical volumetric flasks? https://i.ebayimg.com/images/g/QqkAAOSwg35atCrz/s-l1600.jpg https://i.ebayimg.com/images/g/GLsAAOSwuHZatCr0/s-l1600.jpg

Here - I found them through a simple search, but they do look very expensive.

[Edited on 29-9-2020 by Antigua]
Morgan
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Quote: Originally posted by Antigua
 Quote: Originally posted by Morgan Does anyone know a company that makes these cylindrical volumetric flasks? https://i.ebayimg.com/images/g/QqkAAOSwg35atCrz/s-l1600.jpg https://i.ebayimg.com/images/g/GLsAAOSwuHZatCr0/s-l1600.jpg

Here - I found them through a simple search, but they do look very expensive.

[Edited on 29-9-2020 by Antigua]

I see some cylindrical volumetric flasks there but not the identical shape. There are also square volumetric flasks I found that are close to it in proportion such as this one.
Just now found it.
Morgan
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Quote: Originally posted by Morgan
Quote: Originally posted by Antigua
 Quote: Originally posted by Morgan Does anyone know a company that makes these cylindrical volumetric flasks? https://i.ebayimg.com/images/g/QqkAAOSwg35atCrz/s-l1600.jpg https://i.ebayimg.com/images/g/GLsAAOSwuHZatCr0/s-l1600.jpg

Here - I found them through a simple search, but they do look very expensive.

[Edited on 29-9-2020 by Antigua]

I see some cylindrical volumetric flasks there but not the identical shape. There are also square volumetric flasks I found that are close to it in proportion such as this one.
Just now found it.

I noticed this 2 liter size is listed for $210.89 and probably shipping costs. I decided to buy that shape having found 4 of them (same Kimble 28040 flask) for sale for$34.25 each or best offer on eBay, new old stock so I bought one along with free shipping. The square flask is 5 X 5 X 18 inches.

[Edited on 2-10-2020 by Morgan]
j_sum1

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Anyone able to give any enlightenment as to what this reaction is?

I thought it was a stunning demo and one I would love to add to my repertoire.
CoCl2 I have. But what is the reaction mixture being used? And what kind of complexing causes the green?
DraconicAcid
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 Quote: Originally posted by j_sum1 Anyone able to give any enlightenment as to what this reaction is? https://www.youtube.com/watch?v=cVxySCgUy8A I thought it was a stunning demo and one I would love to add to my repertoire. CoCl2 I have. But what is the reaction mixture being used? And what kind of complexing causes the green?

Might be basic peroxide and carbonate? Or basic peroxide and oxalate?

Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
B(a)P
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https://uwaterloo.ca/chem13-news-magazine/march-2014/activities/sharing-chemistry-community-colorful-catalyst

I think this is what you are after.

j_sum1

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 Quote: Originally posted by B(a)P https://uwaterloo.ca/chem13-news-magazine/march-2014/activities/sharing-chemistry-community-colorful-catalyst I think this is what you are after.

Awesome. that is just great!
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Hello I have a quick question regarding how to convert aniline back to actilanilide? I assum it's simple base hydrolysis? Does anyone know of a decent procedure? I have used TFSE and am coming up with nada. I would rather start from a known procedure then go the route of trail and error as I only have a small amount of the previously stated starting material; as such I would like to optimize the yield.
Antigua
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 Quote: Originally posted by SHADYCHASE54 Hello I have a quick question regarding how to convert aniline back to actilanilide? I assum it's simple base hydrolysis? Does anyone know of a decent procedure? I have used TFSE and am coming up with nada. I would rather start from a known procedure then go the route of trail and error as I only have a small amount of the previously stated starting material; as such I would like to optimize the yield.

Why would it be a base hydrolysis? You have to acetylate the amine, for example using glacial acetic acid and zinc dust.
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I want to convert the acetanilide back to the amine. My desired product is aniline made by reacting acetanilide, I think with a base, to convert it into aniline. Can anyone help me with this?

Antigua
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 Quote: Originally posted by SHADYCHASE54 I want to convert the acetanilide back to the amine. My desired product is aniline made by reacting acetanilide, I think with a base, to convert it into aniline. Can anyone help me with this? Thank you in advance for any help you may provide.

Now it makes more sense! In your original question you mentioned the other reaction, making acetanilide out of aniline.
Anyways, here are some sources you might find useful:
1. Hydrolysis of acetanilide, attached
2. Reactivity of Acetanilides in the Alkaline Hydrolysis Reaction: Theory vs. Experiment, attached

Attachment: article.pdf (522kB)

Attachment: Reactivity_of_Acetanilides_in_the_Alkaline_Hydroly.pdf (533kB)

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Thanks Antigua, sorry if you found my first post unclear, regardless thanks for the reaction information you rock.

Be well.
Johnny Cappone
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Hi, guys!
I have some questions that I don't think are worthy of a topic of their own. These are as follows:

1) Is it possible to concentrate a diluted solution of nitric acid (say, 10%) to its azeotrope (68%) simply by heating it, as is done with sulphuric acid?

2) When I distill concentrated sulfuric acid (98%) and KNO3, do I get fuming nitric acid that boils at 83-6 degrees or the azeotrope?

3) If, on the other hand, I use diluted sulfuric acid (30%) in the previous operation, will I get 30% HNO3 or the azeotrope?

Thanks!
Antigua
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1. Yes
2. Fuming
3. You'd get a solution of HNO3 (less than 68%) that can be distilled fractionally or simply to get the azeotrope.
Tsjerk
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 Quote: Originally posted by Johnny Cappone 1) Is it possible to concentrate a diluted solution of nitric acid (say, 10%) to its azeotrope (68%) simply by heating it, as is done with sulphuric acid? 2) When I distill concentrated sulfuric acid (98%) and KNO3, do I get fuming nitric acid that boils at 83-6 degrees or the azeotrope? 3) If, on the other hand, I use diluted sulfuric acid (30%) in the previous operation, will I get 30% HNO3 or the azeotrope? Thanks!

1) In a perfect world you would boil of the water at 100 degrees, until the nitric acid reaches 68%, which would then come over at 120 degrees. In reality, depending on the efficiency of your fractionation, you will start with acid coming over a little bit over 100 degrees, slowly rising in concentration until it reaches almost 120 degrees.

The efficiency of your fractionation depends mostly on the length of your column and the speed at which you distill the acid.

2) The acid you collect from KNO3 and H2SO4 will be nearly anhydrous, but will contain a lot of NO2. I think adding water to the KNO3/H2SO4 to get azeotropic acid works better in terms of NO2 produced. You can later make anhydrous acid by adding H2SO4 to the 68% HNO3, preferably distilled under vacuum.

3) The HNO3 collected from 30% H2SO4 will behave like the acid in procedure 1. You will first collect less concentrated HNO3, followed by acid closer to the azeotrope.

[Edited on 22-12-2020 by Tsjerk]
artemov
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Just want to do a quick check if isopropanol salted-out with NaCl from 70% is safe to distill?
Antigua
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Why not? Alcohols don't form peroxides like ethers.
teodor
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 Quote: Originally posted by Johnny Cappone 1) Is it possible to concentrate a diluted solution of nitric acid (say, 10%) to its azeotrope (68%) simply by heating it, as is done with sulphuric acid?

The problem is very slope concentration/boiling temperature curve, so it is like most of the acid (4/5 when you start with 50%) goes before azeotrope. The fraction 119-121 degree will contain 50-55% and only when you get the first signs of NO2 inside the condenser you can collect something around 63-68%.
I think addition of sulfuric acid could help, on rough estimation it keeps 20-30% of water by weight of H2SO4 so it will look like you will starting with more concentrated acid vapours.

 Quote: Originally posted by Johnny Cappone 2) When I distill concentrated sulfuric acid (98%) and KNO3, do I get fuming nitric acid that boils at 83-6 degrees or the azeotrope?

When NOx is present the boiling point goes down to 80-81%. You can get either red fuming or white fuming nitric acid but the latest one I believe you can get starting only with azeotrope of high purity (without vacuum). There is a lot of difference between 97.5% and 100% HNO3 (in oxidation power) and if you don't need it as a rocket oxidiser I suggest get it around 98%. This usually will be result when the equipment, the bottle and the air is not perfectly dry.

 Quote: Originally posted by Johnny Cappone 3) If, on the other hand, I use diluted sulfuric acid (30%) in the previous operation, will I get 30% HNO3 or the azeotrope?

I found that the sulphuric acid changes the boiling curve that after azeotrope the distillation returns back to the lower concentration. And in this case most of concentration will no go higher than ~45%, it only touches the maximum with few mls of the distillate and then returns back. I think the sulfuric acid try to keep so much water to become 70-75% sulfuric acid, I think you can roughly estimate the amount you need to add based on this.

[Edited on 24-12-2020 by teodor]

[Edited on 24-12-2020 by teodor]
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 Sciencemadness Discussion Board » Fundamentals » Miscellaneous » The Short Questions Thread (4) Select A Forum Fundamentals   » Chemistry in General   » Organic Chemistry   » Reagents and Apparatus Acquisition   » Beginnings   » Responsible Practices   » Miscellaneous   » The Wiki Special topics   » Technochemistry   » Energetic Materials   » Biochemistry   » Radiochemistry   » Computational Models and Techniques   » Prepublication Non-chemistry   » Forum Matters   » Legal and Societal Issues