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Questions tagged [distillation]

For questions about the process of distillation. For the distillation process used in metal refining, also use the [metallurgy] tag.

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Evolution of distillation system over time

In my example, suppose we had a system of multiple components (benzaldehyde, benzyl alcohol, methyl benzoate) and wanted to separate the mixture using fractional distillation. If we rule out any ...
7 votes
2 answers
1k views

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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How feasible is it to separate acetone, butanol, and ethanol (and water) via simple distillation?

I have no experience distilling, though I understand the basics about it. When two liquids with different boiling points are mixed, you can sometimes separate them by boiling away one of the liquids, ...
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History of Azeotrope (azeotropic mixtures)

I'm currently researching the history of azeotropic mixtures for an essay, and I've come across some interesting information. The term "azeotrope" was coined in 1911 by English chemists John ...
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1 answer
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When Should you use grease to lubricate ground glass joints?

I am getting ready to try steam distillation following this guide which references an earlier chapter which says "If using grease as recommended by your instructor, lightly grease all joints.&...
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2 answers
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In distillation at what stage does purification happen? [closed]

A novice question: is it purified during evaporation or elsewhere? I’m getting a water distiller for drinking water after re-adding minerals for health reasons. I described how it works to my son. He ...
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How to remove color from bromostyrene/dibromostyrene

Distillation under low heat can remove color (excess bromine) but this is time consuming and there is a danger of bromostyrene polymerization even with added TBC. In aqueous, sodium thiosulphate can ...
2 votes
2 answers
249 views

How does steam distillation work to extract a substance from a mixture, below its boiling point?

This is a small confusion I have regarding steam distillation. Let us consider a sample of water mixed with an organic compound that is insoluble in water. Let us also consider that the boiling point ...
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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 ...
1 vote
1 answer
206 views

Distillation thermometer position

I am aware that in theory the position of the thermometer needs to be right at the transition point of the vapor into the condenser. In practice,I don´t reach the exact boiling temp. at this height ...
5 votes
3 answers
3k views

Does distilled water still have ions in it? Does deionized water lack ions, but still have other "stuff" in it?

This isn't a question about the difference between Deionized and Distilled water, my hope is that for once it's actually a chemistry question related to this topic. Distilled water is created by ...
2 votes
2 answers
119 views

Fractional Distillation Question

We're covering fractional distillation in my physical chemistry class. I'm confused regarding this diagram: From your starting point, you heat the binary mixture (in this case benzene and toluene) to ...
3 votes
1 answer
347 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 ...
1 vote
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Fractional Distillation Fractions

Currently, I am trying to remember the order of fractions within the fractionating column. However, I have found a contradiction. Consider the above diagrams, both from reputable sources. The first ...
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Distillation of free fatty acid from soya acid oil

I have soya acid oil with FFA percentage of about 40. After degumming and glycerolysis I am able to bring down the FFA percentage to 5. It does go down to about 2 percentage but it takes an enormous ...
1 vote
1 answer
350 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 ...
2 votes
2 answers
2k views

How can I remove water vapor from an airstream without a cold trap?

I'm trying to perform vacuum distillation at home with a rotary vane vacuum pump. In order to not ruin my vacuum pump, solvent vapor (in my case, water) should be removed from the air before it ...
0 votes
1 answer
259 views

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 ...
1 vote
2 answers
169 views

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 ...
19 votes
5 answers
14k views

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 °...
3 votes
2 answers
222 views

NMR and dienes to isolate certain isotopes?

I am looking to achieve isotope separation using transition states. In the rxn of dienes with halogens, based on the temperature, the dienes can create a thermodynamic product or a kinetic product. ...
3 votes
1 answer
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Does yeast, sugar and water really produce any noticable/significant amounts of methanol?

I just read this question on Quora about distilling during pre-industrial age, which reminded me about multiple discussions I have heard or read during the years about whether the fermentation process ...
0 votes
1 answer
761 views

Vacuum distillation of azeotropic mixtures

I was wondering if vacuum distillation can seperate azeotropic mixtures. Consider the ethanol/water system. At 95.6% ethanol content, the system forms an azeotrope because the vapor composition ...
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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 ...
1 vote
2 answers
162 views

"Cleaning" of HNO3 solution using distillation

In many industries, pickling baths are common. These are 10 cubic meter baths containing acid baths that metal components are dipped into prior to surface treatment. When the metals are dipped, some ...
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2 answers
307 views

What is the difference between distillation temperature and boiling point?

Is there a difference between the distillation temperature and the boiling point of a fluid, in my case kerosene? And if there is, what is the difference?
2 votes
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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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1 answer
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Does each liquid in a binary mixture boil at its boiling point? [closed]

I have been looking for an explanation and can't seem to find one, so I am asking my question on this forum. I appreciate your responses. Consider a binary mixture of cyclohexane and toluene (50% mol:...
5 votes
2 answers
801 views

Why is ethanol distilled off before adding water in the first step of a malonic synthesis?

I am doing a malonic synthesis shown below, and I wonder why I should distill ethanol off before adding water in the first step of the reaction (First I add absolute ethanol and solid sodium).
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Breaking an azeotrope by using different atmospheres?

I read the threads about azeotropic mixtures and distillation, and a question arose: Is it possible to distill an azeotropic mixtures properly (i. e., separate it into its single components) by ...
2 votes
1 answer
173 views

Could fluorinated gases be removed from the atmosphere? [closed]

Background Among all the discussion of 'greenhouse gas removal' (GGR) to aid climate change mitigation, almost all is concerned with removal of carbon dioxide. There are one or two mentions of ...
3 votes
1 answer
270 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 $\...
1 vote
1 answer
238 views

When to use chromatographic separation vs vacuum-assisted rectification distillation?

I'm trying to understand a bit more about industrial scale separation processes. One particular element I'm interested in is the question as to when chromatography (HPLC or Simulated Moving Bed) may ...
3 votes
2 answers
752 views

Stratification of gasses by mass [closed]

Suppose a homogenous mixture of mutually non-reactive gases is isolated in a container so that there are no external kinetic forces (vibration or rotation) that create turbulence or other mixing ...
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Distillation of water and propanone

I distilled a solution consisting of propanone and water and recorded the boiling point of propanone depending on different concentrations. I thought that the boiling point elevation would be the ...
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1 answer
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Distillation of aniline/water mixture

I read from a source that aniline and water can be separated by steam distillation. But isn't this senseless as steam distillation will simply add more water and make separation more difficult?
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4k 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 ...
2 votes
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What factors have the greatest effects on the yield from steam distillation of ginger?

I have a modest home lab setup that I use primarily for steam distillation of plant matter to extract essential oils. My yields are typically at or below the low end of estimates given by different ...
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1 answer
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What is the difference, if there is, between this two distillation methods?

Reading about water vapor distillation, I found two different approaches: Direct Indirect The direct approach has an arrangement like this: Here the chamber contains the water and the plant. It is ...
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1 answer
513 views

Why does the ethanol-water mixture not burn during fractional distillation?

Ethanol-water solution has a flash point lower than ethanol's boiling point in almost all cases. So how is the fractional distillation of the solution possible? Why doesn't the solution ignite? Is it ...
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1 answer
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Is 99% Isopropyl Alcohol sold in stores really 99%?

My understanding is that an azeotropic mixture of isopropanol and water is 91%. This makes sense as to why there are so many brands of rubbing alcohol sold at 91%. There are also some sold as 99%, ...
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206 views

Can ethanol and heat during distillation cause degradation/dissolution of vinyl tubing leading hot vapors of the distillate to the condenser?

I'm a chemist and a qa lab, and we occasionally test herbal remedy products from one of our customers for alcohol content using a distillation, then using the specific gravity of the distillate to ...
6 votes
2 answers
319 views

Alcohol (ethanol) distillation: mystery congener

I regularly home-distil small amounts of potable alcohol (ethanol), mainly from fermented sugar(s) solutions (the 'wash'). My still is a box standard, $4.5\mathrm{L}$ electrically heated (safety!), ...
1 vote
1 answer
152 views

Can the enrichment of Uranium be done via manipulating the boiling/melting point difference between differing isotopes of the same element?

I have a Physics question for which I could not find the answer on the Internet, so I would like to see if y'all know the answer to it. I have found that heavy water will have a different boiling ...
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3 answers
557 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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1 answer
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Why should the conical flask (apparatus on the right) used in Fractional Distillation be left open (without a bung)? [closed]

With context to the image shown, is there a reason as to why the conical flask shouldn't be closed with a bung and is there a way to describe this error?
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Is there such a thing as a temperature-controlled reflux column?

You know the deal - you're doing a distillation in the lab, but want a fraction that comes over at a very specific temperature. I find it very hard to control the temperature in my air-cooled reflux ...
3 votes
0 answers
302 views

Is it possible to vacuum distill citric acid?

I'm wondering if it is at all possible to vacuum distill citric acid without the slightest decomposition; it is something that can easily be done in a small lab with widely available equipment. I've ...
1 vote
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276 views

How concentrated does sulfuric acid need to be for nitric acid synthesis (H2SO4 + nitrate salt distillation)?

So I have a home lab setup and recently found myself in need of some nitric acid. I could just buy some, but I thought it would be a useful exercise to make my own. I have plenty of nitrate salts ...
1 vote
1 answer
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Are all gases equal in their ability to carry with them lower volatility matter at a given temperature? [closed]

As we all know water is a great solvent in it's liquid form relative to other substances. I wonder however how it performs as a gas relative to other stuff. Does anyone know how well steam carries ...