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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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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Is it possible to run column chromatography in reversed phase?

I'm conducting a synthesis involving aza-crown-ether. Whether aza-crown-ether acts as a base or not is unclear, but when I do TLC using dichloromethane/methanol, it hardly goes up. (see image below) ...
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1answer
54 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 e.g we study in steam distillation we reduce the external pressure on the compound to be ...
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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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Inorganic Exclusion Rate to Expect During Recrystalization?

In the following context, what approximate exclusion rate can I expect towards all combined inorganic ions (metals, ...) per recrystalization cycle? Can I expect it to radically evolve along the ...
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5k views

Role of hydrochloric acid and sodium hydroxide in isolation of citric acid from lemon juice

I'm trying to extract citric acid from squeezed lemons. After studying the subject, I found a lab manual [1, p. 68]: ISOLATION OF CITRIC ACID Reagents: Lemon juice (ca. $\pu{100 mL}$ – 3 lemons) $\...
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1answer
59 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 ...
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1answer
59 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 ...
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1answer
46 views

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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Un-denaturing industrial alcohol

I have a question regarding the denaturation of industrial ethanol with methanol to discourage its consumption. The boiling point of methanol is 64.7 °C, while the boiling point of ethanol is 78.37 °...
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66 views

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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1answer
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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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2k views

How to prepare glacial acetic acid from sodium acetate?

What would be the most practical process to prepare glacial acetic acid from sodium acetate? I'm thinking to react the sodium acetate with an acid to convert the solution to acetic acid and sodium ...
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3answers
116 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 ...
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643 views

How to clean copper(II) sulfate crystals from sulfuric acid?

I am going to prepare copper(II) sulfate by electrolysis with sulfuric acid for crystal growing. How would I separate the copper(II) sulfate from the sulfuric acid left over from the electrolysis ...
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What does it mean for meth or any other compound to be 'pure'?

In Breaking Bad, Walter White can cook $99.1\%$ pure meth. In general what does it mean for a substance to be pure? In this case, what exactly does it mean for meth to be pure? Does higher purity mean ...
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127 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 ...
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36 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 ...
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1answer
151 views

Purification of primary amines using Schiff base immobilization

I want to purify all primary amines containing compounds in a complex mixture (cell-extracted metabolites). I'm unaware of any published methods to do so. So I am thinking of making my own using a ...
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3answers
118 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 ...
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2answers
7k views

Recrystallization and purification techniques for getting a pure sample

Could someone explain in detail as to why exactly recrystallization gives a more pure solid sample? As well as why is would be better 'technique' to allow for the crystal to form slowly? I was ...
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3answers
810 views

Removing aluminum oxide from impure silica

We have an assay for a mine. Our goal is to have only silica. Is there a cost effective way to extract the contaminants? The product is a fine powder called diatomaceous earth, or fossil shell flour. ...
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2answers
113 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 ...
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2answers
734 views

Remove salt from dirt

I have a mixture that contains out of dirt/sand and salt. I want to extract and measure the salt. What would be the best way to extract the salt from this mixture?
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1answer
2k views

How to acid-wash sand?

I need some acid-washed sand to smooth out boiling in diethyl ether synthesis. I aready have pre-washed sand for general filtration purposes, but it is not labeled as acid-washed. Unfortunately, I ...
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3answers
1k views

How to extract pure potassium carbonate from ash?

In our village, lots of ash is produced which is thrown off. I want to extract pure potassium carbonate from that ash. I am able to extract the potassium compound and a soluble compound by ...
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0answers
253 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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1answer
43 views

Reduction by Activated Carbon

Does reduction by carbon itself occur when filtration is performed using activated carbon? Is it part of the central mechanisms involved in activated carbon filtration? One of the specificities of all ...
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2answers
155 views

Ways to determine the concentration of alkyl halides in organic solvents

I have a volatile alkenyl bromide dissolved in hexanes. I have to use the halide in a Grignard reaction but separating it from hexanes is hard (the bromide is light sensitive and very volatile). I ...
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3answers
7k views

What are disadvantages of using sublimation vs. recrystallization as a method of purification?

I can only think that a small sample can be sublimed while a bigger sample size can be recrystallized. Are there more?
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1answer
1k views

Isolating salt from sea water using filters

Could a filter be used to isolate salt from sea water? Could we say that the water molecules are smaller than the molecules of salt dissolved in the water. I have no relation to chemistry or physics, ...
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128 views

How do you purify gases formed in electrolysis with a potassium hydroxide electrolyte?

I am interested in the $\ce{KOH}$ vapor that is released with my gasses during electrolysis. I have two questions. What would be the best place to start research on the $\ce{KOH}$ vapor produced in ...
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1answer
273 views

How to make a sephadex slurry

I want to purify crude alpha-amylase with column chromatography. I am using a spehadex 75, but for some reason I can't find any information on how to make the slurry. I can quickly find a lot of ...
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2answers
633 views

Shea Stearin Extraction by Dry Fractionation

I have been able fractionate palm oil and extract palm stearin using the following method: Melt the palm oil (over 80 °C) Keep the melted oil at 33.5 °C for 24 hours (using an immersion circulated ...
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1answer
95 views

Is reverse osmosis a fancy term for filtration?

In Reverse Osmosis (RO) systems, the water to be purified is pushed against a semipermeable membrane and comes cleaner the other side, the path of water is the reverse of regular osmosis, hence the ...
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1answer
148 views

Concentrating sulfuric acid

Since calcium oxalate is 3000 times less soluble than calcium sulfate, would it be possible to concentrate sulfuric acid from let's say $\pu{50\%}$ solution using following steps? : adding calcium ...
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155 views

The most convenient process to purify Oxalic Acid up to a high level of purity

I am set out to purify a batch of commercial oxalic acid with the aim in mind to end up with a highly pure product (starting from $\pu{4,000 ppm}$ total impurities and doing so with basic lab ...
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2answers
343 views

Can separated and purified substances be obtained from a chromatogram?

I am studying chemistry, and I am learning about chromatography. But I am confused about how chromatography is used to ‘separate and purify’ substances. I have learnt about chromatography paper, ...
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64 views

Drying sodium tetraborate for use as a standard

I am currently attempting to purify technical grade sodium tetraborate decahydrate by recrystallization for use as a titration standard. I don't have a requirement for a specific grade or purity. I'm ...
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171 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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2answers
6k views

Denatured Ethyl Alcohol Purification

I have denatured ethyl alcohol which was obtained this formula; In 100 L ethyl alcohol there is 0.8 gr denatonium benzoate and 78 gr tert-Butyl alcohol. Is there any way to obtain absolute ethyl ...
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1answer
78 views

How can I purify Ferric or Ferrous acetate with a very basic lab?

I’ve been trying to make Ferric acetate by mixing vinegar with steel wool and allowing it to react. The result is successful in dying leather or wood black and acting as a mordant. Theoretically there ...
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1answer
3k views

Purification of the Hünig Base

My group uses a lot of Hünig base which needs to be dry and pure. The common procedure we use is to first distill from ninhydrin then from calcium chloride. Apparently the problem is that Hünig base ...
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1answer
256 views

Solar still and how it works

I use a solar still that holds 182 cubic feet of water. Here is how it works: There is an insulator on both sides of the metal bowl. On the outside it covers the whole thing. on the inside it covers ...
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1answer
2k views

Most efficient way to purify household vinegar: distillation or freezing?

I am aware that there are better ways to purify acetic acid out of a water-acid mixture than these, but which one out of distillation (using heat) and fractional freezing (using cold) would gain a ...
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1answer
38 views

Using charcoal to clean water [closed]

I have read about charcoal being used to clean water before it is then boiled or mixed with a UV light stick. I have some questions about this: 1) Does it have to be activated charcoal? 2) Can ...
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Extraction Techniques for Organic Compounds from Aqueous Media

I am looking to attempt an extraction of an organic compound that had just been prepared using a Friedel-Crafts acylation. The compound was prepared in MDC (~20 mL in total). After the reaction, the ...
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1answer
86 views

What is Meant by “Eluting with 1-2% EtOAc/pentane” in Terms of Flash Chromatography?

I am reading the experimental section of a paper, and it states [compound of interest] Isolated as a pale yellow oil after flash chromatography on silica gel, eluting with 1-2% EtOAc/pentane... ...
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1answer
80 views

Can we use HPLC to purify an organic reaction product?

I know HPLC is a form of column chromatography that uses high pressure to pump a sample mixture/eluent through a column. However, I'm not sure if this technique is being used to purify and isolate ...