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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213 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
800 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 ...
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333 views

To heat or not to heat; distillation?

One of the questions in a recent past paper I completed was: One way to make water from the reservoir suitable for drinking is by distillation. Describe how water is distilled. And I answered ...
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1answer
440 views

Chemical desalination

Is there a way to remove salt from water, even just partially, using chemical or filtration methods prior to a reverse osmosis? The problems is that salt is very hard on a reverse osmosis membrane ...
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1answer
1k views

How to separate butane from air?

I work in a manufacturing company specializing in polyethelene foam and I have been struggling to separate butane from air in our warehouse during curing period where all the butane gas used to make ...
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2answers
2k views

Most efficient way to purify household vinegar: distillation or freezing?

I am aware that there are better ways to purify acetic acid out of a water-acid mixture than these, but which one out of distillation (using heat) and fractional freezing (using cold) would gain a ...
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2answers
799 views

Remove salt from dirt

I have a mixture that contains out of dirt/sand and salt. I want to extract and measure the salt. What would be the best way to extract the salt from this mixture?
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2answers
7k views

Denatured Ethyl Alcohol Purification

I have denatured ethyl alcohol which was obtained this formula; In 100 L ethyl alcohol there is 0.8 gr denatonium benzoate and 78 gr tert-Butyl alcohol. Is there any way to obtain absolute ethyl ...
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1answer
4k views

How to check purity of mercury metal

Mercury is a very good solvent for many metals. We have mercury metal available, how do we check for its purity? Is there some kind of test available to verify its purity? And, more helpfully, which ...
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1answer
2k views

How can I isolate glycolic acid from sugarcane juice?

This beginning of a bachelor thesis uses ethylene glycol as a catalyst in the isolation of glycolic acid. I can't find the rest of the article (it ends in the middle of the description) to find out ...
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1answer
401 views

Textbook chemistry vs Real life chemistry and impurities

Long ago when I took chemistry courses in high school and lower, chemistry seemed so simple and elegant. All equations and exercises involved pure elements, pure compounds, with a very clean ...
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1answer
2k views

Mechanism of protein precipitation with TCA

In practice, TCA (trichloroacetic acid) is widely used for quantitative protein precipitation, but so far I have failed to discover the exact mechanism of TCA action. I highly doubt it's just the ...
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1answer
106 views

opperating a distillation column far from flooding

I know that flooding will ruin the performance of a distillation column. There are many correlations (Eckert, kister, billet, etc.) that will tell you when a column will flood based on your fluid ...
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660 views

How to clean copper(II) sulfate crystals from sulfuric acid?

I am going to prepare copper(II) sulfate by electrolysis with sulfuric acid for crystal growing. How would I separate the copper(II) sulfate from the sulfuric acid left over from the electrolysis ...
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1answer
87 views

How to recycle olive oil manufacturing wastes?

The fact that only 20% of the olive used to make olive oil becomes olive oil and the other 80% is spread between hard wastes and liquid water wastes made me want to ask this question. Isn't there a ...
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1answer
445 views

What [if anything] is special about the boiling process of purifying water (excluding temperature)?

I know that water boils at $100~^{\circ}\rm C$. I also know that the standard way to purify water is to boil it for roughly a minute. What I'm curious about is, what properties of the boiling process ...
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1answer
834 views

How to remove dichlorometane from water?

I will have water that have been through dichloromethane. Doing so, the dichlorometane (solubility $2~\%$) will contaminate my water by forming an azeotrop which will have a $38~\mathrm{^\circ C}$ ...
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2answers
536 views

Clarification on Recrystallization concept

Any help you could provide me would be greatly appreciated and I thank you for reading (even if you don't comment) I am in an organic laboratory and as a 3rd chemistry major these concepts usually ...
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167 views

How to purify volatile haloalkanes prepared by Darzens halogenation?

We know that the Darzens method of substitution works on $S_n i$ and is considered the best method in terms of yield of product. Also the side products are $\ce{SO_2}$ and $\ce{HCl}$ so the ...
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1answer
137 views

Is there a way to concentrate the vitamin content of a particular food?

I'm looking for a way to extract vitamins out of common food sources of, well, vitamins. Let's take, as an example, Vitamin A which is commonly found in carrots. A carrot (weighing around 60g) should ...
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0answers
819 views

Cell voltage required for refining copper

If you put Zinc or Iron solids into aqueous copper (II) sulphate solutions, copper solids form spontaneously due to the fact, that Zinc/Iron oxides into ions more willingly than Copper does. And if ...
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0answers
2k views

How to prepare glacial acetic acid from sodium acetate?

What would be the most practical process to prepare glacial acetic acid from sodium acetate? I'm thinking to react the sodium acetate with an acid to convert the solution to acetic acid and sodium ...
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1answer
145 views

Flavor components of high end vodka?

I always thought vodka was just alcohol and water, and that the ideal vodka was one lacking all flavor components characteristic of the grain or potato mash that it was distilled from. I once saw a ...
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1answer
355 views

Does precipitated copper carbonate contain impurities

I recently performed a double replacement reaction between copper sulfate and sodium carbonate to yield copper carbonate as a precipitate. I then filtered the precipitate, but I noticed that the ...
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101 views

Removing harmful gases from automobile exhaust using electrostatic precipitation

If I attach an electrostatic precipitator to a car's exhaust - and also make the smoke pass through an area containing $\ce{NaOH}$ in order to absorb sulfur dioxide - does that mean that the smoke ...
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2answers
4k views

Dry Hydrogen Production

I am building a set-up to produce a controlled flow of dry hydrogen. I'm aiming for around 99.5 percent purity. Am I right in thinking a PEM cell and Deterite drying tube should be fine for this? Or ...
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3answers
14k views

What makes oceanic desalination so expensive?

What specifically makes oceanic desalination so expensive?
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1answer
796 views

Purification of Ethanol

In Vogel's organic book, they have mentioned that in the Lund and Bjerrum method of purification of ethanol, magnesium is added, which forms ethanolate. But they said to activate the magnesium first ...
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1answer
1k views

Comparing purity grades for ethanol

I am trying to determine if the following two grades of ethanol are equivalent: Ethanol absolute, 99.8% Normapur AR (Analytical Reagent) Ethanol alcohol, pure ACS reagent, ≥99.5% Information on the ...
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170 views

How can I purify ethanol from formic / boric / salicylic acid?

I need some ethanol pure and strong enough for technical purposes (fuel, solvent, cleaning agent, dissolving rosin for soldering flux, etc.). Food quality is not required though, denaturated one is ...
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1answer
458 views

Old sample of sodium tetraphenylborate—why it is red?

I have a really old sample of sodium tetraphenylborate. It should be white, but it is red. Does anyone know what was formed and how it influences precipitation of cations in water?
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1answer
96 views

Protein purification with Cobalt

Cobalt exhibits a more specific interaction with histidine tags, resulting in less nonspecific interaction than nickel. For this reason, cobalt is the preferred divalent cation for purifying His-...
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3answers
897 views

Obtain precipitated iron?

Is it possible to obtain pure, precipitated iron with no oxidation by some chemical process? Alternatively is it possible to electrically purify iron using an anode and cathode?
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187 views

Make pure phthalocyanines from phthalocyanine dyes

We need a pure copper phthalocyanine for our experiments. Of course, we can buy it from Sigma Aldrich, but this means we'll have to wait a while. In local area we can buy only dyes which are about 98% ...
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2k views

how to separate gamma-butyrolactone from N-methyl-2-pyrrolidone

Since these two chemicals have different freezing temps (pyrrolidone is $-11~\mathrm{^\circ F}$ [$-24~\mathrm{^\circ C}$] and $\unicode[Times]{x3b3}$-butyrolactone freezes (also called melting) at $-...
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1answer
780 views

Is the following paragraph about steam distillation accurate?

I've been struggling with the various methods of purification of organic compounds. If a question comes up in my examination, asking me to explain steam distillation in my own words, I'd like to know ...
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1answer
969 views

How does the production of pure, crystalline silicon via the Czochralsky or Siemens process?

I have a few questions regarding the production of pure, crystalline silicon: As far as I know Silicon usually appears in nature in the form of sand or $\ce{SiO2}$ and then is split apart and brought ...
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1answer
158 views

Removing trace amounts of water from agricultural grade anhydrous ammonia

Agricultural grade anhydrous ammonia (liquefied gas) contains 2000 ppm $\ce{H2O}$. What would be the process to remove this water to obtain refrigeration grade (<100 ppm $\ce{H2O}$) anhydrous ...
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2answers
944 views

How to purify water with activated carbon?

If I am not mistaken, distilling water does not remove all possible impurities. Chemicals with boiling points less than $100\ \mathrm{^\circ C}$ will be transferred as well. Does the usual tap water ...
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1answer
1k views

How do I purify the resulting compound after a nitro- to amine-group reduction?

I have an aromatic compound that I reduced with either $\ce{Fe + HCl}$ or $\ce{Sn + HCl}$. How would you choose to go about extracting the compound? I'm thinking to dry off all the $\ce{HCl}$, ...
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3answers
28k views

What would be the most suitable solvent for a single-solvent recrystallization?

The compound in question is acetanilide, and the solvents in question are: water, ethanol, and ethyl acetate I was thinking all three would be suitable since upon experimentation, acetanilide ...
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2answers
7k views

Recrystallization and purification techniques for getting a pure sample

Could someone explain in detail as to why exactly recrystallization gives a more pure solid sample? As well as why is would be better 'technique' to allow for the crystal to form slowly? I was ...
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1answer
933 views

HCl/diethyl ether + Nitrogen?

Just wondering if anyone can tell me why bubbling nitrogen through a solution of $\ce{HCl}$/diethyl ether catalyst would remove said mix from my solution. My current thought is that the $\ce{N2}$ ...
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1answer
713 views

Chlorination of Water

Does passing chlorine gas through water form hydrochloric acid or bleach? Also, will a mixture of hydrogen and chlorine gas from electrolysis of brine do the same?
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1answer
3k views

How to obtain pure aniline from a mixture of phenol and aniline?

There is a mixture of aniline and phenol. I need to obtain (just the procedure) pure aniline. So I think the mixture should heat with Zn powder(to convert phenol to benzene) and then I thought to ...
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0answers
909 views

How to crystallize out reaction mixture from DMF?

Reaction was carried out in DMF, and TLC shows that the reaction has completed. But how to separate reaction mixture i.e. product from DMF? Edit Steglich Esterification was carried out and the ...
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1answer
259 views

Solar still and how it works

I use a solar still that holds 182 cubic feet of water. Here is how it works: There is an insulator on both sides of the metal bowl. On the outside it covers the whole thing. on the inside it covers ...
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1answer
1k views

Recrystallization of two unknown compounds?

I managed to separate a binary mixture(in solid form) of two unknown substances into two individual solid compounds. For the separation, I used an acid-base extraction with dichloromethane, NaOH, and ...
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1answer
29k views

Why is crystalline aspirin washed with chilled water in the purification process?

Take as example this or even better this: Wash the crystals with 2-3 ml of chilled water. Why does the aspirin need to be cooled down? And why do we wash the aspirin with chilled water?
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2answers
1k views

What is a good way for a laymen to purify alcohol to near 200 proof?

I'm making herbal and medicinal mushroom tinctures and extracts. Normally I'll use everclear but it isn't cheap and 95% alcohol. Also I don't know what that other 5% is. Is it just water? Is ...