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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When is chromatography regarded as a viable industrial purification strategy?

I understand the basics that chromatography is a fairly slow and expensive process compared to direct synthesis. When a synthesis route is not feasible, the economics become favorable. Not being in ...
ericnutsch's user avatar
2 votes
3 answers
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Storage of air and temperature sensitive reagents

What's your method for storing air/moisture and temperature sensitive reagents? For example: A solid. Should I just blow some argon, screw the lid, put parafilm and put it in the fridge? Can a ...
Daniel Álvarez's user avatar
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Purify ethanol from benzene

In reference to my previous question: Separation of methyl acrylate from ethanol I have successfully get rid of acrid odor by treating ethanol with sodium hydroxide and filtering out the precipitate, ...
Tom's user avatar
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Avoid triethylphosphate as a side product during P-C-P coupling reaction with diethylchlorophosphate with LDA

I have a reaction in which I perform a deprotonation of an acidic proton at a phosphate and later do a P-C-P coupling. The coupling partner is diethylchlorophosphate. Deprotonation is performed with ...
raptorlane's user avatar
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Why does brandy have a higher methanol-to-ethanol ratio than beer, despite the distillation?

From my googling, beer tends to contain around 16mg/L of methanol. While for brandy, typical methanol content is around 1000mg/L (give or take a factor of 3, depending) The distillation that brandy ...
MWB's user avatar
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2 answers
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Organic solvents distillation for purification

I've realised that the majority of the solvent that we use in my lab are contaminated with grease (peaks at 1.26 and 0.86 ppm in $^1H$ NMR in $CDCl_3$), since they come in plastic containers (I guess ...
Daniel Álvarez's user avatar
5 votes
1 answer
459 views

Why is kerosene being used in PUREX (plutonium uranium reduction extraction) as a solvent?

I am searching for a reason, why organic solvent in PUREX consists of 30% tributyl phosphate (TBP) in kerosene. Why kerosene (or another hydrocarbon)? What properties does it have? What exactly does ...
user132092's user avatar
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Choice of nonsolvent in polymer purification by reprecipitation

Recently, I have synthesized new polymer. To purify the polymer, I tried reprecipitation. Because general nonsolvent is methanol, I dissolved the polymer in dichloromethane and reprecipitated into ...
Krang Lee's user avatar
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How to separate the salts within homemade sea salt

Goals There are a few things that I'm looking to do: Separate salt from seawater via some evaporation technique. Separate the each of the major salts from the resulting sea water to get each into ...
Mailbox's user avatar
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Is there some other way to perform fractional distillation without using Vigreux Column?

So recently I was performing an esterification reaction of oils like peanut oil or any neutral oil where I got some products which are only possible to filter using fractional distillation. I already ...
Santhosh Sathyamurthy's user avatar
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Destination of carbonyl compounds free toluene

I am currently in the process of trying to get toluene free of carbonyl compounds using a distillation processes with DNPH. Unfortunately I am no distillation expert. And am running into some problems....
Christiaan Zweegers's user avatar
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Removing Copper from drinking water by Electrolysis? What to keep in mind?

The drinking water in my flat contains a lot of copper. Although the amount of copper is around the allowed limit 2mg/l I would prefer to reduce it. I know that it is at this value from a paid ...
datenheim's user avatar
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Air purifier: What is the reaction mechanism between HCHO and negative oxygen ion

Multiple government and commercial sources claim that the negative oxygen ion generated by air purifier can reduce HCHO concentration. However, on google scholar, I find neither the reaction formula ...
dodo's user avatar
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How to remove hydrofluorosilicic acid from water?

I'd like to come as close as possible to pure water. Would a KF filter remove hydrofluorosilicic acid? If not, what would? I could not find the concentration of hydrofluorosilicic acid, but would like ...
Woodsman's user avatar
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Polymer purification by reprecipitation troubleshooting

I am synthesizing new polymer that has not been reported before. The structure of the polymer is based on indacenodithienothiophene unit and thiophene. I used Stille polymerization. As monomers, I ...
Krang Lee's user avatar
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Would it make sense to filter air through oil?

I have seen water-based air purifiers, which work by having air bubble through water supposedly leaving water-soluble molecules behind. I understand that this concept also humidifies the air due to ...
Diydumbster's user avatar
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Mixture is eluted too early from alumina in flash column chromatography

I have recently tried to purify my reaction mixture by column chromatography. Because my reaction mixture had poor resolution in silica-based TLC, I used neutral alumina-based TLC plate. After I ...
Krang Lee's user avatar
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A new green method for purifying acetylene with the help of Zeolite molecular sieve

I'm investigating for a green method for purification of acetylene in order to reduce the environmental impacts in manufacturing plants. In the current method mercuric chloride is used in the ...
Reza Koohpaee's user avatar
1 vote
0 answers
62 views

Recovery of precipitated polymer

I have recently newly synthesized the polymer. Based on its structure I tried to precipitate its concentrated solution in dichloromethane by dropping it into methanol. It seemed to work. The methanol ...
Krang Lee's user avatar
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1 answer
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What chemical reactions takes place in purifying acetylene?

Acetylene produced by water on calcium carbide method contain several impurity compound, that are harmful for welding or other purposes of acetylene and needs to be absorbed from the gas mixture ...
Reza Koohpaee's user avatar
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1 answer
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What are good ways to anticipate co-crystalization of different metal ions?

What rationale (purely theoretical/assumptive, or known by experience / backed by evidence) would you use in an attempt to effectively anticipate which other metal or elemental ions are most likely to ...
Hans's user avatar
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Why is desalination waste usually disposed back into the sea instead of converting it into chemical products?

I was reading about the desalination processes such as reverse osmosis and capacitive deionization and their alternatives. They all work on removing ions from water and disposing them back to sea/...
Belal Bahaa's user avatar
1 vote
0 answers
225 views

Activating alumina before column chromatography

Recently I synthesized some amine compounds, and because it showed better separation in the neutral alumina TLC plates than silica plates, I am planning to purify the reaction mixture using neutral ...
Krang Lee's user avatar
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2 votes
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Evaporation of sample solvent and redissolving

When I conduct a synthesis, after some workups, I usually evaporate large amount of solvent using rotovap, recover compounds sticked to the wall of the flask to the glass vial using small amount of ...
Krang Lee's user avatar
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1 answer
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Purifying ferrous sulfate

For my wood staining experiments I have purchased 1 kilo of ferrous sulphate as a source of iron(II). It turned to be quite oxidised (yellowish) and the its solution is muddy yellow instead of green. ...
e_asphyx's user avatar
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7 votes
2 answers
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Why is NMP developing a yellow color after distillation?

I got an aqueous mother liquor of N-methyl-2-pyrrolidone (NMP) from some reaction I was running and when I redistilled it under vacuum, it came out colorless but turned yellow the next day. I am ...
Pulkit Sharma's user avatar
1 vote
0 answers
65 views

Fragmentation behavior of spots in TLC

I tested multiple development using eluent condition hexane + 1% of ethyl acetate. Then I observed kind of fragmentation of spot. I'm not sure, but I guess that successive spots are from the skyblue ...
Krang Lee's user avatar
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2 votes
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Using neutral or basic alumina in column chromatography for purification of amines

I am conducting a synthesis involving amines, and it is found that some spots still hardly moves from the starting point in spite of the dichloromethane 9:methanol 1 eluent condition. Addition of ...
Krang Lee's user avatar
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1 vote
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Reaction Workup and Quenching

In the supporting information of synthetic paper by Buchwald's group, They use 2-MeTHF as solvent (See B. General Procedures for Amination part, page 8). After the reaction ends and cools the mixture ...
Krang Lee's user avatar
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How can I determine the purity of an oligonucleotide solution?

After desalting an oligonucleotide via gel chromatography, I am left with (presumably) an oligonucleotide substance suspended in a buffer. What is the simplest way to verify the oligonucleotide's ...
RecyclingBen's user avatar
1 vote
1 answer
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Water vapor permeation to the reaction flask

I am conducting a synthesis involving Buchwald-Hartwig coupling. The scale is $\approx10^{-4}$ mols of reagents. After running the reaction at 80 ℃ during 24 hours I found that sealing between the 3-...
Krang Lee's user avatar
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1 vote
0 answers
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How does ethanol separates salts from proteins [closed]

Grad student here messing around with famed TRIzol isolation protocol and looking to optimize the protein yield at the end. There are more direct ways to get protein from a sample but I like getting ...
TheCodeNovice's user avatar
2 votes
0 answers
872 views

The use of far-infrared ceramics for water purification?

I am struggling to understand how exactly far infrared ceramic balls help purify the water. It is stated that active ceramic taormine balls help purify the water by forming a 2 micrometer wavelength ...
Albertthephilosopher's user avatar
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0 answers
424 views

Cleaning used frying oil with salt water : what is the point of using salt?

In the process of making soap from used frying oil, I need to purify the oil. I filtered the cooking oil but I also want to remove the polar compounds that are formed during frying : free fatty acids, ...
Raphael's user avatar
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0 answers
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If I have an oil that contains an impurity that's more soluble in water than in oil, is there a way to "wash out" the impurity with water?

Maybe this question is better classified as "physics" than chemistry, but I'm trying it here. Suppose I'm concerned about a substance S that is highly soluble in water and less soluble in ...
James's user avatar
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2 votes
0 answers
246 views

Analysis of reaction mixture by TLC and finding column chromatography condition

I am conducting an organic synthesis. Below is the TLC image. I used dichloromethane:methanol:triethylamine=10:1:0.15 as eluent, but I stored it during 3 days, so it may be a little bit concentrated. ...
Krang Lee's user avatar
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3 votes
0 answers
107 views

Purification of Buchwald-Hartwig amination

I am conducting a synthesis involving Buchwald-Hartwig amination. I use $\ce{Pd2(dba)3}$, $\ce{P(o-tol)3}$, and $\ce{Et3N}$ as base. In many proposed mechanisms, they often omit the precatalyst. I ...
Krang Lee's user avatar
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5 votes
2 answers
188 views

Should I do solvent extraction for Buchwald–Hartwig amination?

I am conducting a synthesis involving Buchwald–Hartwig amination. Catalyst is $\ce{Pd2(dba)3},$ ligand is $\ce{P(o-tol)3},$ base is $\ce{Et3N},$ and solvent is toluene. Image below is the proposed ...
Krang Lee's user avatar
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1 vote
0 answers
684 views

Leakage during Celite filtration

I'm conducting a synthesis involving crown ether and Pd catalyst. In many papers, prior to column chromatography, they filter crude mixture through a Celite pad. I tried to, but leakage of Celite ...
Krang Lee's user avatar
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3 votes
1 answer
261 views

How can I filtrate Pd2(dba)3 and P(o-tol)3? (Celite filtration failed)

I am conducting an organic synthesis involving Stille coupling, using $\ce{Pd2(dba)3}$ and $\ce{P(o-tol)3}$ as catalysts. Reaction solvent is toluene in which the catalysts also dissolve. Many texts ...
Krang Lee's user avatar
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3 votes
1 answer
139 views

Is it possible to filter Stille catalysts using syringe filter?

I'm conducting an organic synthesis involving Stille coupling. Stille coupling uses $\ce{Pd2(dba)3}$ and $\ce{P(o-tol)3}$ as catalysts. Both catalysts dissolves in toluene which is the solvent of my ...
Krang Lee's user avatar
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1 vote
1 answer
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Microfiltration for saturated solutions of highly hygroscopic compounds?

Is it possible to pass saturated solutions of compounds with very high solubility through filters with small pores (e.g. passing a saturated aqueous ZnCl2 solution at 90C through a 2mcm glassfiber ...
Hans's user avatar
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0 votes
1 answer
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Is it possible to functionalize silica gel as Activated Carbon can be? How?

Activated carbon and Silica gel both have a high surface area. If I understand correctly it is possible to trap stuff inside activated charcoal pores to give it specific retention properties (by ...
Hans's user avatar
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-1 votes
3 answers
476 views

Doubt regarding steam distillation

According to my textbook, in steam distillation the liquid boils when the sum of vapor pressure due to the organic liquid and that due to water becomes equal to the atmospheric pressure. Why? I did ...
Massmarikamayamaranam's user avatar
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1 answer
1k views

What chemical could be used as carbon monoxide scrubber?

I am trying to produce nitrogen by passing air over a heated tube of coals. This leaves a mixture of $\ce{CO},$ $\ce{H2O}$ and $\ce{N2}.$ Only $\ce{CO}$ is unwanted in this case. Could I use calcium ...
Francis L.'s user avatar
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1 vote
1 answer
311 views

Steam distillation vs fractional distillation

I am a high school student and I am a little confused in the techniques used to purify organic compounds. For example, in steam distillation we reduce the external pressure on the compound to be ...
Arun Bhardwaj's user avatar
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0 answers
44 views

Related to liquid-liquid extraction

I was reading about purification of organic compounds and I came across this. I quote below, a line from the excerpt that caused my confusion. The organic solvent is later removed by distillation or ...
Desai's user avatar
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3 votes
1 answer
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How to separate copper(II) chloride from 4-iodophthalic anhydride?

I am planning a reaction in which I iodate phthalic anhydride. My reaction is I2, phthalic anhydride, and copper(II) chloride as a catalyst. The solvent is 99.9% isopropanol. How do I separate the ...
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2 votes
3 answers
245 views

Synthesis of anhydrous sodium tungstate

I am interested in preparing an anhydrous sample of sodium tungstate (Na2WO4), which is normally found as the dihydrate. Finding an example of this in literature is proving difficult, I am interested ...
Tristan Maxson's user avatar
1 vote
2 answers
782 views

If stirring negatively affects crystal purity, why is it so?

My Intellectual Expectations Intuitively, I would expect strong stirring to improve crystal purity during the process of crystalization. My rationale is that strong stirring would increase contact ...
Hans's user avatar
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