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].
210 questions
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How to recrystalize 3,5 dimethoxy aniline after years of oxidation
I want to purify a quantity of 3,5 dimethoxyaniline so i can use it in a N-formylation reaction. The reagent has gained a black color from years of oxidation. Which solvent should i use for the ...
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How to remove DMI solvent from acid sensitive crude reaction mixture?
I performed a reaction in DMI (1,3-Dimethyl-2-imidazolidinone) solvent, which contains acid-sensitive vinyl borinic ester product as shown below.
It has an exact mass of 364.2, whose trace could be ...
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How can I make sure my oil do not contain salt
Vacuuming slightly wet wood with my vacuum pump resulted in making a mayonnaise with my pump oil - which turned out surprisingly stable. I mixed salt saturated water with it in order to break the ...
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Palladium coupling reactions and purification
I tried to synthesize 2-(6-fluoropyridin-3-yl) acetic acid from 5-(Chloromethyl)-2-fluoropyridine using Pd(OAc)2/PPh3 catalyst,Na2CO3 and DCC. I eluted my product on TLC with Ethyl acetate/hexane/...
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Exchange of Fluorine to Oxygen for Fluorophosphonic acid by silylating agents or other methods?
[Warning, long post!]
Dear all,
I am confronted with a seemingly easy transformation. I want to remove a fluorine atom at a fluor phosphonic acid salt. The usual method to achieve this is the basic ...
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Making an UV inactive salt UV active during purification of charged anion with HILIC purification?
In the context of a purification setup I am asking myself the question: Can a UV inactive charged substance made be UV active by a counter ion that absorbs UV light during a column run?
If so, when no ...
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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 ...
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Storage of air and temperature sensitive reagents [closed]
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 ...
user78790
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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, ...
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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 ...
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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 ...
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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 ...
user78790
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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 ...
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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 ...
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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 ...
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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....
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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/...
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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 ...
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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 ...
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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. ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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-...
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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 ...
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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 ...
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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, ...
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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 ...
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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.
...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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