June 18, 2021, 08:26:15 PM
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Water is reactive under certain conditions. Keeping water out of your reactions and work ups helps prevent nasty side reactions.
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I am an undergraduate researcher in a photochemistry lab. I am currently studying the photo physical changes that occur upon thionation of naphthalimide derivatives. The current procedure I'm following results in a tar-like substance. The next step is to crash out the product in chloroform and methanol. The result of filtering is a very static-y black powder. The NMR has shown that the solid I have is my very impure product (it worked, yay!!!).

The next step in the procedure was to recrystallize the solid in anhydrous ethanol. The paper doesn't give a reason for doing so and a search on google, web of science, and scifinder was not very helpful. Why would you want to recrystallize in anhydrous solvent? And does this have to be done under an inert atmosphere?
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Analytical Chemistry Forum / Re: How to standadize NaHCO3 using HCl
« Last post by Asim on Today at 04:19:05 PM »
A Two-Stage Reaction
When you add a hydrochloric acid (HCl) solution to a solution of sodium carbonate (Na2CO3), the hydrogen ion in HCl switches places with one of the sodium ions in Na2CO3 to produce sodium hydrogencarbonate, also known as sodium bicarbonate (baking soda), and sodium chloride (salt).

Na2CO3(aq) + HCl(aq) → NaHCO3(aq) + NaCl(aq)

Sodium hydrogencarbonate is basic, and it reacts with the HCl still in solution to produce sodium chloride, carbon dioxide and water.

NaHCO3(aq) + HCl(aq) → NaCl(aq) + CO2(g) + H2O(l)

Phenolphthalein is a good indicator for the first reaction because it responds to the pH change caused by the formation of sodium hydrogencarbonate. It is pink in basic solutions and turns colorless as soon as the solution becomes acidic. Methyl orange, on the other hand, responds to pH changes associated with the formation of NaCl, changing from yellow to red as the solution becomes more acidic. At neutrality, it is a distinct orange color

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I think your analyt curve is not present. You are seeing only curve obtained in blank..
You must try to change the mobile phase.
And clean apparatus by tap water and rinse by De-ionised water at the end.
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Analytical Chemistry Forum / Eosin-Y indicator use
« Last post by Asim on Today at 04:05:49 PM »
Eosin-Y indicator is Untied State pharmacopea mentioned indicator.
But in titration , final colour of indicator disappears on standing the solution for 2 minutes.. also it does not give sharp colour change . Thats why no satisfacory results are obtained..
Can any one help how to get accurate results using Eosin-Y indicator ??
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Citizen Chemist / Re: Fine Particle Extraction from Solvent
« Last post by billnotgatez on Today at 12:01:03 PM »
evaporation?
rotovap?


If one removes acetone via rotary evaporation, what will happen to the crystal bond?


My suggestions are wild stabs at a possible answer to the problem and @Babcock_Hall  has rightly called me on them.

But in the spirit of wild debate

Suppose that the crystalbond goes into solution with the acetone.
Suppose the dust particles are then floating in the solution.
Suppose that the dust particles eventually settle to the bottom or are encouraged to go to the bottom via centrifuge.
Suppose that the liquid is evaporated and leaves behind the crystalbond and dust in distinct layers
Could one harvest the dust from the bottom.
Sounds too optimistic to me

another possibility is combination of crystalbond and acetone evaporates together
highly unlikely don't you think?

The suggestion by the OP of using a soxhlet to somehow tease away the crystalbond from the solution is up for discussion.



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Citizen Chemist / Re: Fine Particle Extraction from Solvent
« Last post by Babcock_Hall on Today at 10:54:11 AM »
If one removes acetone via rotary evaporation, what will happen to the crystal bond?
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Mostly mumbo jumbo.

The recipe at the beginning can be to some extent correct (that is, assuming we know what are all the mentioned substances and how to understand the procedure).
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On the Separations of the Elements from Metals.
"Take salt nitre, vitriol, and alum, in equal parts, which you will distil into aqua tortis. Pour this water again on its faeces, and distil it again in glass. In this aqua fortis clarify silver, and afterwards dissolve in it sal ammoniac.
Having done this, take a metal reduced into thin plates in the same way,
that is, in the same water. Afterwards separate it by the balneum Manse,
pour it on again, and repeat this until there be found at the bottom an oil, namely, from the Sun, or gold, of a light red colour ; of the Moon, a light blue ; of Mars, red and very dark ; of Mercury, white ; of Saturn, livid and leaden ; of Venus, bright green ; and of Jupiter, yellow. All metals are not thus reduced to an oil, except those which have been previously prepared. For instance. Mercury must be sublimated ; Saturn calcined ; Venus florified ; Iron must be reduced to a crocus ; Jupiter must be reverberated ; but the Sun and Moon easily yield themselves. All metals are not thus reduced to an oil, except those which have been previously prepared. For instance. Mercury must be sublimated ; Saturn calcined ; Venus florified ; Iron must be reduced to a crocus ; Jupiter must be reverberated ; but the Sun and Moon easily yield themselves. earth and fire. For from the cold and the moisture is produced the substance and corporality of the Moon, which is, indeed, of a fixed nature, and cannot be elevated. From Mercury there remains fire at the bottom, and earth and water are elevated upwards. From Venus there also remains fire, and both, that is to say, earth and water, remain in the bath. From Saturn there remains the element of earth at the bottom, while fire and water are held in the bath. From Jupiter air remains at the bottom, while fire, water, and earth are elevated therefrom. (...)"

THE THIRD BOOK OF THE ARCHIDOXIES,
From the Theophrastia of Paracelsus the Great.

What this guy is saying make any sense chemically?
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Citizen Chemist / Re: Fine Particle Extraction from Solvent
« Last post by billnotgatez on Today at 09:59:51 AM »
evaporation?
rotovap?
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