Questions tagged [separation-techniques]

For questions about the separation of mixtures and solutions into pure compounds

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Distilling milligram quantities of oil like it's late 1970s

In a currently retracted* manuscript by Tomas Hudlicky [1, Retraction Watch] the following has been noted: Fifty years ago professors took an active part in all laboratory instructions and they ...
andselisk's user avatar
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How can should one separate and purify benzophenone from salicylic acid?

I am working with two solids and I know that they are benzophenone (s)(ketone) and salicylic acid (s) (carboxylic acid). I am curious to know what is/are the best method of extraction and ...
Boo's user avatar
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How to adjust selectivity of gas-permeable PDMS membranes for environmental applications?

I have an idea about making an environmental sensor that uses a gas-permeable membrane (GMP) and how its probe could be submerged in a water source with an off the shelf gas sensor. So far, my ...
John P Santos's user avatar
2 votes
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132 views

How to choose the solvent gradient for the flash column chromatography of a complex mixture?

When performing a flash column chromatography, it is advised to select an eluent in which the desired compound has an $R_\mathrm{F}$ of about $0.25$ in TLC. However, if I want to separate and isolate ...
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Purification of Red Phosphorus

The Boring Stuff I'm well acquainted with various fields of science & engineering, but my foray into the world of chemistry is relatively recent. I'm in a location (probably most of us are to some ...
voices's user avatar
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Is there a way to form only ortho product without using fractional distillation?

Using benzene and ethane as your only source of carbon in the final molecule, synthesize the following using any useful reagents. Reaction must form pure ortho compound. I have to form the product ...
Sydney Clark's user avatar
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Hypothetically, can sufficiently powerful centrifugation separate normally miscible chemicals of differing densities?

Centrifugation is used to separate phases in suspensions by density. I read that this is not possible with colloids and solutions, but the distinction between the three seems to be optical properties ...
BatWannaBe's user avatar
1 vote
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How can I isolate products that cannot be cleanly distilled or visualised by TLC for column chromatography?

I am a first year PhD student in the UK, and without giving too many details of my work as it is industrially funded and my sponsors are a bit touchy over IP, I am struggling to isolate the products ...
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Separation of methyl acrylate from ethanol

I have liters of ethanol contaminated with methyl acrylate (MA) from cleaning UV resin 3D prints. Is there an easy way to purify this ethanol by separating MA (as unwanted product) from it? ...
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My particles won’t separate without neutralizing the solution. I want to understand why?

I etched active carbon with a concentrated KOH solution and added HCl to neutralize the KOH. Separeted the particles with centrifuge at 4000 rpm. They should be micron sized. My boss asked me to stop ...
marietiara's user avatar
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are refractometers generic?

I need to check the presence (and also purity approx) of a substance in solution. I have a very good reference (10mg/1ml - the substance in water). Can I use a refractometer to do this? I am trying to ...
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Protein purification pressure limits confusion, about the X-MPa limit for FPLC?

I have always been a bit confused about column pressure limits. I have to elaborate a bit on the problem to get to my question: In protein purification we use the äkta purification machines (e.g. ...
CuriousTree's user avatar
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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 ...
jawad ali's user avatar
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How to separate rhodium sulfate from zirconium sulfate?

I dissolved a zirconia ceramic containing rhodium with sulfuric acid, i tought this process will dissolve only zirconia ZrO2 at 100 °C and lower but it turned out that rhodium in form of powder can ...
Tintin's user avatar
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When creating a separation method in gas chromatography, calibration with compounds mixture or for each separate component?

When creating a separation method in gas chromatography, is there any difference between the calibration with the compounds mixture and the calibration for each separate component? I have 5 components....
DiMorten - Jorge Chamorro's user avatar
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Calculation of the Seperation factor of Ethanol / Water rectification based on two saturated vapor temperatures

I want to calculate the efficacy of a Water / Ethanol rectification based on two temperatures with help of a vapor-liquid equilibration diagram. The first temperature is measured right above the ...
Neidi's user avatar
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How to remove oil/grease contaminant from an aqueous solution?

I have a solution of water and calcium nitrate that is contaminated with some sort of heavy petroleum oil, semi-solid at room temperature a bit like petroleum jelly, and a strong odor of very crude ...
Max Power's user avatar
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Dynamic viscosity of gas mixture (appropriate estimation)

What estimation of the dynamic viscosity $\eta = f(T)$ $([\eta] = \pu{Pa·s})$ of the gas mixture components would you recommend during adsorption at a low temperature, approx. $\pu{293 K}$ to $\pu{333 ...
Josh E.'s user avatar
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Solubility Product, and it's relation to solubility

In order to remove temporary hardness of water, it is boiled. On boiling, while Ca(HCO3)2 gives CaCo3(ppt.) , Mg(HCO3)2 gives Mg(OH)2(ppt.). According to my book precipitation of Mg(OH)2 occurs due to ...
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Method of separating product and conserving the catalyst

I'm looking for a way to separate reaction product of iodobenzene with ethyl 2-methyl-3-oxopentanoate in 1,4-dioxane (toluene is an alternative as a solvent). The catalyst being used is $\ce{Pd2(DBA)3}...
steve d.'s user avatar
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coffee concentrate and water separated after 2 hours. How/why?

I'm asking because this makes no sense to me and making sure I'm not stupid. I brewed 10 gallons of cold brew concentrate(TDS 12.2) and mixed it with 10 gallons of water. I moved 10 gallons of the ...
notnotderrick's user avatar