Questions tagged [purification]

For questions about purification - the process of rendering something pure, clean of foreign or undesired elements. Not to be confused with [metallurgy] or [chromatography].

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What is the most convenient way to purify Mg from Al>As>Cd?

I'd like to bring down these impurities <0.1ppm (most concerned in the order of Al>As>Cd). For As I guess I could oxidate my Mg sample (by calculating its carbonate salt?) and then dissolve & ...
0
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1answer
46 views

Would dissolving Mg in NH3 help me purify Mg from all elements other than Li, Na, K, Rb, Cs, Fr, Ca, Sr, Ba, Eu and Yb? [on hold]

According to Wikipedia all of the alkali metals, as well as $\ce{Ca, Sr, Ba, Eu,}$ and $\ce{Yb}$ (also $\ce{Mg}$ using an electrolytic process[4]), dissolve in ammonia to give the characteristic blue ...
3
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1answer
48 views

How do I remove tetrabutylammonium perchlorate from an organic synthesis?

I am trying to remove tetrabutylammonium perchlorate (TBAP) from an organic synthesis where TBAP was used as an electrolyte. I am working with compounds containing the amide group. I have used flash ...
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1answer
30 views

In HPLC, how does column diameter affect the retention time?

I am using a smaller diameter column than my previous one keeping all other factors such as stationary phase, solvent, solvent gradient constant. (Obviously, flow rate will be less in smaller column). ...
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0answers
21 views

Remove ethanol from gasoline by mixing it with water?

I have read on forums that ethanol can be removed from commercial gasoline by mixing it with water, then draining water from the bottom to remove the water-ethanol solution (for example, with a ...
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0answers
19 views

What zeolite types are typically used to absorb CO and CO2 gases at maximum zeolite absorption temperature?

Me and my friends are doing a project involving carbon monoxide and carbon dioxide as products to be filtered, we are using zeolites and would like to know the zeolite type typically used to filter $\...
3
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3answers
651 views

Is there a method to separate iron from mercury?

The mercury is contaminated with iron. Is there any way to remove iron from mercury?
2
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1answer
53 views

Techniques to extract lipids

I am planning an experiment on how to isolate casein and part of the process involves removing any lipids that may still be in it after filtering the precipitated casein out of the milk. I have read ...
6
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2answers
405 views

Recrystallisation of dibenzylideneacetone

Recently, I carried out the synthesis of dibenzylideneacetone. I had a lot of problems with the purification process, especially the part involving recrystallisation. I was instructed to carry out the ...
2
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1answer
222 views

Shea Stearin Extraction by Dry Fractionation

I have been able fractionate palm oil and extract palm stearin using the following method: Melt the palm oil (over 80 °C) Keep the melted oil at 33.5 °C for 24 hours (using an immersion circulated ...
0
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1answer
101 views

How to remove MEHQ from Methacrylic acid monomer without reduced pressure distillation?

I am aware that the standard way to remove MEHQ from Methacrylic Acid is to perform reduced pressure distillation. The papers I see suggest using ~ 10 Torr pressure to perform distillation. Sandler's ...
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1answer
2k views

When using a “dilute hydrochloric acid” solution, how diluted should it be?

Quite often when reading through some instructions or documentation or an outline that I've found online (EG: acid-base extractions), theres a step that involves using a "dilute hydrochloric acid ...
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1answer
569 views

How to acid-wash sand?

I need some acid-washed sand to smooth out boiling in diethyl ether synthesis. I aready have pre-washed sand for general filtration purposes, but it is not labeled as acid-washed. Unfortunately, I ...
2
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0answers
33 views

What is the future of water treatment, and why we don't use enough purified sea and freshwater? [closed]

I understand thermal and membrane distillation are very expensive and that slowed down their usage, but now we can bring 100% clean energy to power them. Except the set-up, the price of materials and ...
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0answers
37 views

Removing chloride ions from humic acid purification

I used HF and HCl in humic acid purification, and now I need to remove the Cl ions from solution. What should I do to remove the Cl ions? Do I just wash it with distilled water, or is there another ...
2
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1answer
2k views

How to separate sodium carbonate from sodium hydroxide?

I got a drain cleaner in dust form, which consists of $\ce{Na2CO3}$ and $\ce{NaOH}$. I wanted to extract the $\ce{NaOH}$ so I tried to heat the mixture in order to just melt the sodium hydroxide, but ...
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2answers
864 views

What acid can dissolve thorium dioxide?

In one of my projects (which is about alpha-voltaic cells, don't worry, I know that thorium isn't a strong alpha source, it's only for measurements) I would need to get water soluble thorium compound ...
4
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1answer
112 views

How to remove nitrose gasses from ozone gas mixture?

I produce ozone gas with an ozone generator based on corona discharge principle. These kind of ozone generators have the disadvantage that if $\ce{N2}$ is present, a bit of $\ce{NO}$ and $\ce{NO2}$ ...
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0answers
184 views

Refining Tin (Sn)

I am a Copper Cookware Tinner & have a problem in reusing much of the tin that I end up sweeping off the floor etc. Prob about 5kg over the year & it would be great to save this? Now, my ...
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1answer
2k views

Synthesis of Benzaldehyde and Aniline Schiff Bases

I have a problem while synthesize the schiff base. I synthesized using absolute ethanol as solvent and use reflux method for 4 hours generally. The problem occur on TLC where there is still two spot ...
3
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2answers
82 views

How does % purity on household products work?

For example, toilet bowl cleaner is 9.5% HCl. Does this mean that for every 90.5 moles of H2O (or other stuff) there is 9.5 moles of HCl? Does it mean that for every 90.5 g of H2O there are 9.5 g of ...
2
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1answer
149 views

Ester as a side product in the synthesis of bromoalkane from alcohol. Is it correct?

About 5 months ago, I answered a very interesting question albeit a very simple one. Why do we need sulfuric acid in creating alkyl bromide and not in creating alkyl iodide from alcohol and ...
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0answers
262 views

Multi-solvent recrystallization to extract solute from glycerol?

I have compound A contaminated with impurity B. Recrystallization in water would not yield pure compound A since impurity B is less soluble in it. The only solvent in which substances A and B have ...
4
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1answer
624 views

How to remove pyridine from Reaction mixture containing chiral molecule with diacetal protection group?

While working with chiral molecule, we have pyridine in our reaction mixture. Molecule has four chiral centre and protection group-diacetal and acetyl groups which may break in harsh conditions. ...
2
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1answer
211 views

Zinc Sulfate Purification

In the process for electrolysis for zinc, three things must be done: Leaching the ZnO Purifying the ZnSO4 by means of cementation Performing the electrolysis However, step 2, as it is presented by ...
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1answer
167 views

How do chemists measure purity in high purity metals and other reagents?

I have noticed that gold bars are often marked "999.9" fine: Whenever I have metallurgical assays done, they always seem to do them with ISP or DSP or whatever, some spectrometer-based system. These ...
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2answers
2k views

Pure substances have only one kind of atom

I read in a book recently that no substance is ever totally pure, even if we take great care to separate it from other substances. And also that pure substances contain only one kind of matter. But I ...
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1answer
566 views

Crystallization in a solution of 2 or more solutes

This is a very basic question I found myself wondering. For simplicity's sake, we'll say it is a super saturated aqueous solution of an equivalent measure of sugar and salt. As the solution cools and ...
6
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1answer
437 views

How does activated carbon trap impurities?

I've tried and I've tried to find an answer to this all over the web, but I can't seem to find an in depth explanation. To the best of my knowledge, activated carbon has a very microporous structure ...
2
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1answer
109 views

Minimizing Catalyst Residue in Vegetable Oil Hydrogenation

We are using a nickel catalyst in our hydrogenation process to help convert vegetable oil to vegetable wax. The issue is ensuring all additives are successfully removed once hydrogenation is complete. ...
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0answers
432 views

Purification of polar NHS esters

What are the options that I might be missing for the purification of a molecule with the following characteristic: Contains an activated ester that reacts with water (NHS) Reacts readily with ...
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1answer
194 views

Purification of isoborneol [closed]

How can I convert isoborneol powder to isoborneol flakes? I have made the isoborneol powder from reduction of camphor using sodium borohydride.
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1answer
1k views

Purification of the Hünig Base

My group uses a lot of Hünig base which needs to be dry and pure. The common procedure we use is to first distill from ninhydrin then from calcium chloride. Apparently the problem is that Hünig base ...
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1answer
834 views

How to separate two aqueous salts?

I have a mixture of two aqueous salts, $\ce{Cr(OH)3}$ and $\ce{NaNO3}$ and I'd like to separate them and purify the $\ce{Cr(OH)3}$ in order to make $\ce{KCr(SO4)12 . H2O}$ (Chromium Alum). Does any ...
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1answer
122 views

How to prepare elemental gallium from a mixture of gallium and aluminum nitrate?

How would one go about preparing and purifying elemental gallium from a mixture of aluminum(III) nitrate and gallium(III) nitrate?
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2answers
585 views

Removing aluminum oxide from impure silica

We have an assay for a mine. Our goal is to have only silica. Is there a cost effective way to extract the contaminants? The product is a fine powder called diatomaceous earth, or fossil shell flour. ...
2
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1answer
6k views

Why is the solid product washed with ice-cold solvent during in the last stages of recrystallisation?

Why is the solid product washed with ice-cold solvent during in the last stages of recrystallisation? Is this to remove soluble impurities? (for example) Well, what if the impurities were also ...
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1answer
61 views

Purify gas produced after reactions with sulfuric acid

Say, I preheat 50ml of 98% $\ce{H2SO4}$ and proceed with adding 25ml of 85% $\ce{HCOOH}$. The result of which is: $$\ce{H2SO4 + HCOOH -> CO + H2O}$$ Sulfuric acid will dehydrate formic acid ...
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0answers
92 views

How to make a sephadex slurry

I want to purify crude alpha-amylase with column chromatography. I am using a spehadex 75, But for some reason I can't find any information on how to make the slurry. I can quickly find tons of ...
2
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1answer
328 views

How to obtain pure alcohol from mixture of alcohol & carbonyl? (Grignard experiment) [closed]

If one discovers that after finishing up a Grignard reaction that their alcohol product has been contaminated with the carbonyl starting material, how could they separate the alcohol from the carbonyl ...
2
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1answer
4k views

Why is % yield in a purification table measured using activity instead of total protein?

I'm trying to understand why % yield is measured with activity instead of total protein in mg. According to my biochemistry notes, activity is "1.0 units of enzyme activity = 1.0 μmol of substrate ...
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0answers
2k views

Removal of calcium from calcium-ammonium nitrate?

I am interested in model rocketry, and need to produce small quantities of pottasium nitrate. For this process I need ammonium nitrate, but I only have calcium ammonium nitrate. Is there a simple ...
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1answer
22 views

How to liberate propylthiouracil

Two substances undergo a reaction that gives off propylthiouracil and another compound as products. Is there an additional compound I could throw into that sludgy product to strain off the $\ce{...
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1answer
3k views

Does UV water purification cause cancer? [closed]

I found out that a relative is using a machine that performs UV water purification at home (for drinking). There seems to be a distinct difference from the water that is not purified by it. Is it ...
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0answers
47 views

What needs to happen to this: Ca5(PO4)3Cl to get this: CaCl2?

$\ce{Ca5(PO4)3Cl}$ is a mineral called Chlorapatite So lets say I have some chlorapatite in my garage, what do I need to do to it so that I am left with Calcium Chloride $\ce{CaCl2}$?
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1answer
1k views

How to reduce Tin Oxide

We have a pilot atomization setup where we atomize molten tin to produce tin powder. Unfortunately a lot of tin is wasted and oxidized. I have found this video on which looks promising. Is this the ...
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2answers
3k views

What are disadvantages of using sublimation vs. recrystallization as a method of purification?

I can only think that a small sample can be sublimed while a bigger sample size can be recrystallized. Are there more?
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0answers
607 views

How to get anhydrous triflic acid from triflic anhydride?

I require a small amount of triflic acid, and while other research groups do not have any, I did locate some trflic anhydride. Does anyone have a published protocol for obtaining the anhydrous acid ...
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1answer
1k views

Confirming the presence of 4-bromoacetanilide during bromination of acetanilide

In my lab, acetanilide was added to bromine in aqueous acetic acid, and discolouration of the reaction mixture was obtained, indicating that bromine was consumed. After some discussion, it was ...
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3answers
8k views

What does it mean for meth or any other compound to be 'pure'?

In Breaking Bad, Walter White can cook $99.1\%$ pure meth. In general what does it mean for a substance to be pure? In this case, what exactly does it mean for meth to be pure? Does higher purity mean ...