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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36 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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50 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 ...
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1answer
4k 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
1k 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 ...
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1answer
126 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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297 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
3k 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 ...
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2answers
402 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 ...
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1answer
249 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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325 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 ...
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1answer
1k 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. ...
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1answer
486 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
292 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
3k 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
948 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 ...
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1answer
562 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 ...
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1answer
131 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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780 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
449 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
3k 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
2k 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
204 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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3answers
810 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. ...
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1answer
20k 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
77 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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1answer
273 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 a lot of ...
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1answer
613 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 ...
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1answer
9k 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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4k 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
36 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
4k 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
62 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
2k 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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3answers
7k 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
833 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
2k 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
11k 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 ...
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1answer
1k views

Why are 'table salt and sugar are both terrible candidates for recrystallization'?

I received a comment on one of my other chemistry questions stating that table salt and sugar are both terrible candidates for recrystallization, albeit for different reasons. Why are salt and ...
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6answers
9k views

Un-denaturing industrial alcohol

I have a question regarding the denaturation of industrial ethanol with methanol to discourage its consumption. The boiling point of methanol is 64.7 °C, while the boiling point of ethanol is 78.37 °...
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5k views

Role of hydrochloric acid and sodium hydroxide in isolation of citric acid from lemon juice

I'm trying to extract citric acid from squeezed lemons. After studying the subject, I found a lab manual [1, p. 68]: ISOLATION OF CITRIC ACID Reagents: Lemon juice (ca. $\pu{100 mL}$ – 3 lemons) $\...
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2answers
255 views

Concentrating Oxalic Acid by Evaporation

I bought Oxalic Acid in an aqueous solution from a hardware store years ago. I need to turn it to powder form for easier storage and other things. Can I simply evaporate the solution? I seem to ...
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2answers
1k views

Calculating the theoretical percent purity of a recrystallization

The sample contains some percent A and some percent B with A being the majority. The solubility for both is given at two different temperatures. One where both are very soluble and one where both are ...
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2answers
931 views

Can we do column chromatography for the purification of metal complexs?

In case of organic ligands there are several techniques for purification, but in case of metal complex (using $\ce{Cr,Mn,Fe,Co}$ as central metals), I have not seen any literature for the purification ...
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1answer
849 views

Purification/Extraction of Sodium Permanganate

I read this question and answer, and it seemed like a rather nice way to make sodium permanganate. Using the method with sodium hydroxide, I produced a solution. Once filtered and decanted, it was ...
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1answer
245 views

CO2 conversion to a harmless gas like oxygen [duplicate]

I am doing some research about indoor purifiers and I was wondering if there is any approach to purify co2 or convert it to harmless gases like oxygen just like what plants do.
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2answers
22k views

Extracting urea from urine

What is a process for the extraction of urea from urine? These are the steps I have come up with: Add 2-propanol to get rid of any bacteria present. (The 2-propanol likely contained some sodium ...
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2answers
4k views

Removal of tetrabutylammonium from an organic reaction

I need to synthesize some organic compound for my Ph.D. research. Everything went OK during the synthetic route but got messed up at the very end. In my final step (once the final compound has been ...
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1answer
1k views

Removal of water from sulfuric acid

Suppose I have a dehydration reaction of methanol to produce methoxymethane: $$\ce{2 CH3OH(l) ->[H_2SO_4] C2H6O(g) + H2O(l)}$$ Usually, people will use sulfuric acid to dehydrate the methanol. ...
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2answers
210 views

Drying solvents while taking care of purity

I need to dry some solvents like $\text{MeOH, EtOH, and DMSO} $ and I have to take care of purity of the solvents. These solvents are HPLC grade. I am interested in freezing point and boiling point ...
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1answer
777 views

Removal of octadecanoic acid from paraffin wax

I have some very plain candles. I don't think they contain anything but paraffin wax and octadecanoic (stearic) acid, since they are odorless and very hard to bend, tending to crack instead (even at ...