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 ...
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4 votes
0 answers
378 views

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 ...
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3 votes
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36 views

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 ...
2 votes
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767 views

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 ...
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2 votes
0 answers
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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 ...
2 votes
0 answers
46 views

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 ...
1 vote
0 answers
33 views

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 ...
1 vote
0 answers
178 views

How do I get calcium citrate to precipitate in experiment on extraction of citric acid from juice?

I was planning to extract citric acid from mango juice by first using Aspergillus niger fungus by fermentation to convert the mango juice to citric acid, then extracting by first adding sodium ...
1 vote
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32 views

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 ...
1 vote
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92 views

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. ...
1 vote
0 answers
57 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 ...
0 votes
0 answers
30 views

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 ...
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38 views

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 ...
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130 views

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 ...
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43 views

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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62 views

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}...
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44 views

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 ...
-4 votes
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37 views

Would it be possible to separate and identify plastic compounds/mixtures?

In the lab I have been trying to identify and quantify the ratios of different components of sampled plastic compounds. The ingredients are generally known: Polymer matrix (PE or PP) Pigments (...