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Organic Chemistry Forum / Re: Degradation of aspartame at pH 8
« Last post by Babcock_Hall on Today at 10:33:36 AM »The starting material, aspartame, has a free amino group and should be positive in a ninhydrin test.
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Analytical Chemistry Forum / Re: Does N,n-dimethylformamide show up on TLC?
« Last post by Babcock_Hall on Today at 10:13:56 AM »It should not absorb strongly. Its presence may change Rf values of other compounds, depending upon the solvent system. I have sometimes thought about removing it from TLC samples, but I have not actually done so.
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Physical Chemistry Forum / Salt solution separation
« Last post by roilaa on Today at 07:46:13 AM »I have a solution containing approximately 200 g/L NaCl and 100 g/L KCl. I am trying to separate into the individual salts but without a huge energy input if possible. By chilling the solution the KCl should crystallise first, which should make it filterable but is there any easier way to do this?
Any help greatly appreciated.
Any help greatly appreciated.
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Inorganic Chemistry Forum / Re: help
« Last post by Borek on Today at 02:59:09 AM »Please read the forum rules, you have to show your efforts at answering the question to receive help.
Technically you should start by writing the reaction equation, after that calculations are rather easy.
That being said I am not convinced the obvious reaction that you can find here and there by googling is correct, my bet is that the process of thermal decomposition of KSCN is not something that follows a well defined, stoichiometric path, which makes the result of simple calculations unrealistic.
Technically you should start by writing the reaction equation, after that calculations are rather easy.
That being said I am not convinced the obvious reaction that you can find here and there by googling is correct, my bet is that the process of thermal decomposition of KSCN is not something that follows a well defined, stoichiometric path, which makes the result of simple calculations unrealistic.
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Inorganic Chemistry Forum / help
« Last post by Ethan1122664 on Today at 12:35:00 AM »How much KCN can be produced by heating 10 grams of 99% pure KSCN at 500 degrees Celsius?
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Analytical Chemistry Forum / Re: HOCL shelf life problem
« Last post by Borek on Yesterday at 05:08:24 PM »Acidifying the solution is a sure way of speeding up the decomposition.
Buffers composition is typically calculated using Henderson-Hasselbalch equation, see examples here: https://www.chembuddy.com/buffers-composition-calculation
Buffers composition is typically calculated using Henderson-Hasselbalch equation, see examples here: https://www.chembuddy.com/buffers-composition-calculation
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Analytical Chemistry Forum / Re: HOCL shelf life problem
« Last post by Hunter2 on Yesterday at 03:49:18 PM »Hydrochloric will destroy immediately to chlorine.
HOCl + HCl => H2O + Cl2
For cleaner it's better to have NaOCl not the acid.
HOCl + HCl => H2O + Cl2
For cleaner it's better to have NaOCl not the acid.
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Organic Chemistry Forum / Re: Degradation of aspartame at pH 8
« Last post by rolnor on Yesterday at 03:36:37 PM »Ninhydrin is not good for this, make solutions in NMR tubes and run spektrum after the reaction time is up. Use D2O DCl and NaOD. Or monitor by HPLC
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Analytical Chemistry Forum / HOCL shelf life problem
« Last post by angzukofi on Yesterday at 02:03:07 PM »[Chemistry/Math problem at end]
I've been making homemade HOCL(hypochlorous acid) and it doesn't last very long. I've been trying to find a way to prolong the shelf life, beside the obvious store in opaque PET container away from direct sunlight. (which by the way I have it in a spray bottle... I don't think the straw or sprayer mouth is PET, does that matter?)
One potential solution is adding phosphoric acid to act as a preservative and at the same time lowing the pH to my desired pH.
Another is adding hydrochloric acid to lower the pH and then adding a phosphate buffer like sodium phosphate to act as the preservative.
Now my question is, which solution would leave me with a cleaner or more stable product, and how much of each product do I need to add?
Say I have 6 liters of HOCL at a 6 pH
how much mL phosphoric acid do I need to add (and does it need to be 85% phosphoric acid?) To stabilize it at 5 pH. (explanation and formula would be greatly helpful for my future reference to calculate myself)
Now say I have 6 liters of HOCL at 5 pH (thanks to the hydrochloric acid) (from advice another told me that phosphoric acid does not mix well with hydrochloric acid and should not be added but instead a phosphate buffer) how much sodium phosphate should I add to have the same preservative effects of phosphoric acid (and does that affect the pH?)
Can I do add multiple preservative steps to prolong the shelf life more without tampering the HOCL pH and ppm ?
Does anyone know a better way to preserve the pH for up to 2 years?
I've been making homemade HOCL(hypochlorous acid) and it doesn't last very long. I've been trying to find a way to prolong the shelf life, beside the obvious store in opaque PET container away from direct sunlight. (which by the way I have it in a spray bottle... I don't think the straw or sprayer mouth is PET, does that matter?)
One potential solution is adding phosphoric acid to act as a preservative and at the same time lowing the pH to my desired pH.
Another is adding hydrochloric acid to lower the pH and then adding a phosphate buffer like sodium phosphate to act as the preservative.
Now my question is, which solution would leave me with a cleaner or more stable product, and how much of each product do I need to add?
Say I have 6 liters of HOCL at a 6 pH
how much mL phosphoric acid do I need to add (and does it need to be 85% phosphoric acid?) To stabilize it at 5 pH. (explanation and formula would be greatly helpful for my future reference to calculate myself)
Now say I have 6 liters of HOCL at 5 pH (thanks to the hydrochloric acid) (from advice another told me that phosphoric acid does not mix well with hydrochloric acid and should not be added but instead a phosphate buffer) how much sodium phosphate should I add to have the same preservative effects of phosphoric acid (and does that affect the pH?)
Can I do add multiple preservative steps to prolong the shelf life more without tampering the HOCL pH and ppm ?
Does anyone know a better way to preserve the pH for up to 2 years?
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Analytical Chemistry Forum / Does N,n-dimethylformamide show up on TLC?
« Last post by Tom_Boomer on Yesterday at 12:53:26 PM »Hey everyone, I am currently working on my Bachelor's thesis for which I am conducting an organic reaction. I am using TLC (with a "build-in" visualizer at 254nm UV) to monitor my reactions. As I am using N,n-dimethylformamide as a solvent in my reaction, I was wondering whether it would also show up on the TLC if I were to take a sample. Thanks for the help in advance!
