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Questions tagged [separation-techniques]

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

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-3 votes
0 answers
28 views

Can i separate oil from paint thinners

I have a drum of paint thinners which has been used to clean engine parts and has a high content of engine oil in it. When pouring it into another drum it is transparent black and still quite thin in ...
4 votes
1 answer
343 views

Meaning for chromatography terms linear velocity and volume flow rate

I am learning about chromatography and there are two terms that confuse me a lot: linear velocity and volume flow rate. These terms are defined in Daniel Harris's Qualitative Chemical Analysis: ...
1 vote
2 answers
453 views

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 ...
2 votes
0 answers
48 views

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/...
0 votes
0 answers
114 views

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 ...
1 vote
0 answers
61 views

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 ...
-4 votes
1 answer
262 views

Separation of benzoic acid and naphthalene from its mixture [closed]

The best method for the separation of naphthalene and benzoic acid from their mixture ? a)chromatography b)crystallization c)distillation. d)sublimation many sources says answer is crystallization ...
3 votes
1 answer
366 views

How can I read an Anschütz/Bennert manometer and how can I make sense of it?

Recently I have come across a mercury-filled manometer for vacuum distillation that somewhat resembles a U-tube shaped manometer, but with one arm sealed and completely filled with mercury. Searching ...
3 votes
3 answers
3k views

How to separate a mixture of sodium chloride and sodium hydroxide?

I recently did a double displacement reaction in which I formed a solution of water with sodium hydroxide and sodium chloride dissolved in it. Now I want to separate both of them. How can I do this?
1 vote
0 answers
41 views

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? ...
1 vote
1 answer
355 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 ...
0 votes
0 answers
54 views

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....
5 votes
1 answer
367 views

How to effectively replace DMSO with LC–MS-compatible solvent for the samples from a well plate?

I want to do LC–MS analysis of the samples from a 384-well plate where each compound (at around 1–10 μM) is dissolved in 10–15 μL of DMSO. I am worried about the DMSO dwarfing the analyte’s signal, as ...
1 vote
1 answer
214 views

How to interpret gas chromatography results?

I am having trouble interpreting gas chromatography (GC) results for the production of ethyl acetate from acetic acid and ethanol. I am trying to find the reaction order from these results, as well as ...
-3 votes
1 answer
296 views

How can titanium be separated from magnesium by washing?

I saw this question in a GCSE past paper: After this reaction, there is a mixture of the solids magnesium, titanium and magnesium chloride. Titanium does not react with dilute hydrochloric acid. ...
3 votes
3 answers
2k views

Why does a molecular sieve work for gas separation?

I was looking at membrane separation of air to nitrogen / oxygen and saw some details on the molecular sieve which on Wikipedia states you can get much higher purity from an adsorber / sieve, but when ...
2 votes
0 answers
146 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 ...
1 vote
2 answers
264 views

How does industry separate glucose from fructose using liquid chromatography when producing high-fructose corn syrup?

Can someone explain how the separation of glucose and fructose is achieved using liquid chromatography in the industrial production of high-fructose corn syrup? I've seen references to ion-exchange ...
2 votes
1 answer
427 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 ...
2 votes
1 answer
7k views

How viable is production of magnesium oxide and sulfuric acid from Epsom salt?

Epsom salt $(\ce{MgSO4})$ is really cheap (less than 0.5 €/kg), whereas $98\,\%$ or better grade magnesia $(\ce{MgO})$ is much more expensive (3 to 4 €/kg). Is it possible to convert magnesium sulfate ...
2 votes
3 answers
3k views

Which process would separate the mixture of toluene, cyclohexane and water?

I think that answer would be: Toluene and cyclohexane do not dissolve in water (since they are nonpolar), so I would first separate the water from the mixture with a separator funnel. A mixture of ...
3 votes
3 answers
2k views

Can I separate paint thinner into acetone and toluene by simply boiling it?

I have a paint thinner that contains 60% toluene and 40% acetone. I would like to obtain some more-or-less pure toluene. Considering the big difference in boiling points (110°C toluene vs 56°C acetone)...
6 votes
1 answer
768 views

What is the correct unit of a RI detector used for HPLC analysis?

I analyze sugar compounds in soft drinks with HPLC using refractive index detection (RID) on Agilent 1260 Infinity Binary LC (System User Guide (PDF)). I am not sure which unit to put next to the $y$-...
2 votes
1 answer
186 views

Is it possible to separate $\ce{CO2}$ from exhaled air? How?

Just for fun, I would like to see if I could make my own concentrated $\ce{CO2}$ by separating it from my own exhaled breath. I would also love to see if I could pressurize it so I could make my own ...
-2 votes
2 answers
223 views

How do we separate H2O from CO2? [closed]

Let's say I have a mixture of $\ce{CO2}$ and $\ce{H2O}$ gases. I've read that $\ce{CO2}$ is heavier (molar mass is $\pu{44.01 g/mol}$) than $\ce{H2O}$ (molar mass is $\pu{18.02 g/mol}$). So, if the ...
0 votes
1 answer
139 views

What matters for ion exchange: net or local charge?

I am interested in separating two small organic molecules by ion exchange chromatography. Following the example set by several old papers for these molecules, I want to use a cation exchanger. Both ...
2 votes
1 answer
240 views

Is Silica Gel fit for Ultra-High Dessication?

I had the (perhaps wrong) notion that silica gel wasn't that strong of a dessicant, especially compared to CaO, MgO, CaSO4, H2SO4, KOH, Mg(ClO4)2), but I've been exposed to information* that might ...
-1 votes
3 answers
651 views

How to make clean water from urine in a wastewater treatment plant? [closed]

Referring to a video here, describing a filter that treats wastewater, wouldn't urine in the wastewater not get filtered out because a sand filter alone does not separate urine from water? How is ...
0 votes
0 answers
91 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 ...
3 votes
1 answer
272 views

Separation of methanol–water mix in a plate distillation column

I conducted an experiment to separate methanol and water. I am trying to determine the mole fraction of the distillate collected but having a little trouble with the calculation. The flow rate was $\...
0 votes
1 answer
70 views

Why does a big protein move during gel electrophoresis but to a lesses extent through a size exclusion column?

A big protein going through gel electrophoresis will be forced through the gel, it will drift a small way and will show on the top of the gel, while in size exclusion, the big protein is not forced to ...
5 votes
2 answers
6k views

Reaction of amines with diethyl oxalate (Hofmann amine separation method)

Why does only one molecule of secondary amine react with diethyl oxalate and two molecules of primary amine react with diethyl oxalate? I feel secondary amine also should have reacted similar to ...
1 vote
1 answer
156 views

How does a freeze-thaw cycle separate a mixture?

Imagine that I defrost a tube of serum (only the yellow stuff, with blood cells removed) standing still and upright in ambient air. I have seen that as it defrosts the sample separates into different ...
0 votes
0 answers
54 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 ...
4 votes
2 answers
561 views

What solvent dissolves calcium nitrate but not ammonium nitrate?

I am experimenting with a precipitation reaction between ammonium sulfate solution and calcium nitrate. Calcium sulfate precipitates and can be filtered out easily. I am wondering if there's a way I ...
-4 votes
1 answer
37 views

Separation methods [closed]

I put some iron nails in water, and obviously, those started oxidizing, making those hydrogen bubbles. Some days after, the water was orange, indicated that the FeO has just dissolved in it. I found ...
3 votes
1 answer
125 views

Why can I extract all metabolites from blood plasma with one solvent, but to extract only fatty acids I must use many solvents?

I want to do a metabolite study using GC- without derivatization and UPLC-MS (RP and NP) on samples of plasma and urine. My hypothesis is agnostic about which metabolite will correlate with the ...
1 vote
0 answers
35 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 ...
2 votes
1 answer
249 views

How do I separate an Indium-Gallium alloy into Indium and Gallium?

I've recently learned more about Indium and Gallium, and I find them quite interesting, especially how an alloy can be manually made simply by rubbing them together. I'm curious though, is there a ...
2 votes
1 answer
117 views

Has anyone added dyes to a mixture about to separated by chromatography in order to visualize where the desired product lies?

Usually in preparative chromatography one needs to know when the desired substance to be separated is coming down the pike. Often this required some sophisticated instrumentation. But, it occurred to ...
3 votes
0 answers
47 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 ...
1 vote
1 answer
266 views

What is the function of thin layer in thin layer chromatography?

I just learned about the thin layer chromatography, which I think is basically the same as the paper chromatography. I am wondering what is the function of the thin layer? I mean, what's special about ...
-1 votes
1 answer
63 views

How to separate manganese(IV) oxide and chromium(III) hydroxide?

I am trying to find a reagent that keeps either $\ce{MnO2}$ or $\ce{Cr(OH)3}$ solid and make other soluble so I can centrifuge or use filtration. I thought of $\ce{NaOH},$ but I could not find any ...
3 votes
2 answers
2k views

What is the principle of “scrubbing” in liquid extraction or solvent extraction?

There are many steps in solvent extraction: Extraction Scrubbing Back extraction I understand the 1st and the 3rd. What is the principle of scrubbing? Is it just washing the organic phase? How ...
3 votes
1 answer
138 views

How are Silanol groups functionalized unto mesoporous silica structures?

As described in this research paper: Immobilization of Jacobsen type catalysts on modified silica, Jairo Cubillos , Edwing Grajales, Santiago Vásquez, Consuelo Montes de Correa, Rev. Fac. Ing. Univ. ...
3 votes
1 answer
370 views

How do you separate microcrystalline cellulose from amino acids in a powder mixture?

I am looking to separate out the microcrystalline cellulose that has been mixed in with amino acids in a powder mixture. I have tried suspending the powder mixture in water and then filtering out the ...
0 votes
0 answers
66 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}...
8 votes
2 answers
1k views

How to separate Cu and Ni from alloy containing different metals such as Al, Cu, Ni, (Zn, Pb, Sn < 5%)?

I have an alloy containing different metals such as Al, Cu, Ni, (Zn, Pb, Sn, Ag, Si in small amount < 5%). How can I separate Cu and Ni from this alloy? I tried to dissolve alloy in sulfuric acid, ...
2 votes
1 answer
7k views

How to remove sugar from juice

My son has autism and we noticed that blueberries make him feel much better. The problem is blueberries contain sugars which interfere with diet he has (low carbohydrate). How do I filter out the ...
5 votes
1 answer
847 views

What is the state of stationery phase in paper chromatography?

As per my textbook: Partition Chromatography: Partition chromatography is based on continuous differential partiotioning of components of a mixture between stationary and mobile phases. Paper ...