Sciencemadness Discussion Board

The Short Questions Thread (4)

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clearly_not_atara - 4-6-2019 at 14:48

Anyone have any references discussing the Lucas reagent and other acidic Sn2 reactions on vicinal diols?

In particular, I’m interested in the practicality of converting propylene glycol into 2-chloro-1-propanol. The secondary alcohol should be substituted faster than the primary, but I don’t know if there are any side reactions to worry about.

Incidentally, while researching this transformation, I was unable to find any references discussing the conversion of ethylene glycol to 1,2-dichloroethane, even though this transformation is commonly suggested as a route to DCE.

Abromination - 14-6-2019 at 14:42

Anyone have any suggestions on paints they have found chemically resistant? I am painting my fumehood soon.
Much appreciated

TLC Quiz

Pumukli - 27-6-2019 at 11:20

It seems that after a lot of struggle I could finaly prepare that nicotinonitrile I asked about months ago.

I ran the starting niacinamide and the crude product side by side on a tlc plate (Kieselgel on aluminum) in 6:14 denatured EtOH : Chloroform. They each gave one spot only.

I'm curious who would guess the resulting Rf values most accurately?! ;)

This "challenge" is open for a few days then I'll announce the results!

Anyone for a ride?

Abromination - 26-7-2019 at 18:01

According to pubchem.gov, 2 ethylhexanol is a brown liquid, however various images of the substance show it to be clear. Which one is it? I feel like the images are just showing a generic liquid in a flask.
Here is an example:


38B2D701-D086-47E5-93FF-FF9C9E578ED0.jpeg - 25kB

Pumukli - 26-7-2019 at 20:01

2-ethylhexanol why should it be brown? It is a simple aliphatic alcohol of which the C-chain isn't too complicated (no conjugated double or triple bonds) so there are no chromofors.
I imagine it should look exactly like 1-octanol, maybe slightly more viscous.

Herr Haber - 29-7-2019 at 03:41

Quote: Originally posted by Abromination  
Anyone have any suggestions on paints they have found chemically resistant? I am painting my fumehood soon.
Much appreciated


I recently discovered "graffitiy proof" paints based on a fluorinated polymer that also takes advantage of a phenomenon I didnt look into.
It could be great for fumehoods.

The price was not so great though... Almost 200 Euros / liter !

Abromination - 29-7-2019 at 18:06

Quote: Originally posted by Pumukli  
2-ethylhexanol why should it be brown? It is a simple aliphatic alcohol of which the C-chain isn't too complicated (no conjugated double or triple bonds) so there are no chromofors.
I imagine it should look exactly like 1-octanol, maybe slightly more viscous.

Thanks, just checking, pubchem has usually been a reliable source in the past.

Panache - 1-8-2019 at 19:32

Quote: Originally posted by bipolar  
Does acetonitrile react with sodium metal? If so, what are the products of this reaction?
I'm hoping this might be the way to make some sodium cyanide. :D


[Edited on 21-4-2019 by bipolar]


gaseous acetonitrile decomposes to HCN, a simple tube furnace (600-900C if i recall, anyway the process has 4768543983465430 references online as it is critical for fire fighters in buildings with certain types of polymers, acetonitrile became the test standard for assessing this risk) connected to a boiling flask of acetonitrile with the exiting gas stream cooled with a long air condenser then bubbled through two NaOH or KOH wash bottles, indicated to clearly show when exhausted. Clever use of three way taps will allow for changeover of the solutions.
Less safe in some respects is condensing the HCN, however it does allow one greater flexibility, ie you can weigh precise amounts out to neutralise.
Be very careful, i hear HCN has deliterious health consequences to the human organism.
Always run a lengthy test cycle at temp through your setup with compressed air or something testing for leaks.

mayko - 9-8-2019 at 08:18

So I have heard this a few places, some easily dismissed as technobabble (eg The X-Files) and others less so (Mythbusters iirc). This is that at high temperatures, the dissociation of water will create hydrogen and oxygen, which will then go on to fuel and augment the fire.

Am I completely missing something??? Isn't the whole point of their dissociation at high temperature that their combination is unfavorable? Isn't any energy released by their eventual combustion energy that the flame had previously lost? Is there some sort of potential energy transport effect I'm neglecting?

C6(NO2)5CH2CH(CH3)N(NO2)2 - 5-9-2019 at 16:09

@Mayko, I know this thread is dead, but I think your reasoning is right, and that theory is a crock of crap. The dissociation takes a certain amount of heat, but as soon as the gas gets to the flametip and even cools down by a few degrees, it recombines and makes water, releasing precisely as much energy as it took to heat it. They might as well say that pouring liquid water into a fire will heat it up, since it makes so much hot steam. The only difference is that most laymen know about evaporative cooling, but don't know about the reversible pyrolysis of water, so poorly informed popular TV shows can speculate about it without too many people calling BS. Now, if the steam stays well insulated at a few dozen megakelvins for years on end, nuclear reactions will slowly heat it up. Also, if you started out with room temperature hydrogen and oxygen and mixed them, then that will obviously heat up quite rapidly when ignited. other than those two possibilities, adding extra water into a fire will just cool it.

Dissociation does have an effect in making the peak flame temperature a bit lower, and the total moles of gas at peak temperature a bit higher, but to say it raises the temperature or adds any energy is grossly inaccurate.

Now, I've got a question. At a hardware store, I saw some Klean-Strip "green" muriatic acid, which claimed to have 90% less fumes than normal muriatic. The safety datasheet says it's 20% HCl. Do you think it simply gives off less fumes due to being diluted to <30%. or is there some other additive to supress fuming?

[Edited for format, and because I just realized the last question was old)

[Edited on 6-9-2019 by C6(NO2)5CH2CH(CH3)N(NO2)2]

magnet - 6-9-2019 at 05:42

My thermometer adapter popped up and out at the end of my last distillation because I was negligent in using a keck clip..ugh. so ordered a new one but it's different and didnt realize the system will be open using this(I use my multimeter for thermometer). I thought of filling hole with aluminum foil but I'm sure that would react with something sooner or later. Any ideas how to seal around wires? Sorry about volume level thru pic..damn phone is a pitas to screen shot.

Screenshot_20190906-070342_Chrome.jpg - 168kB

[Edited on 6-9-2019 by magnet]

j_sum1 - 6-9-2019 at 06:13

Four options.
  • Hot glue gun
  • Lots of teflon tape
  • Silicone sealant
  • Buy the adapter you want

    Sulaiman - 6-9-2019 at 06:15

    Heat seal (melt) the end of some 8mm o.d. borosilicate tubing and put the thermocouple in the glass tube.

    Pumukli - 6-9-2019 at 06:21

    To polynitrosomeone: yes, just dilution. Why, what did you think? :) No special additives, nothing. It would cost money, anyway! Dilution is cheap - but can be explained away as the most important scientific breakthrough in the XXI century. :) Like "x % less fuming"! :)

    magnet - 6-9-2019 at 06:55

    Thank you for the suggestions.

    Organic reactions with chlorate?

    Ramium - 6-9-2019 at 17:45

    I recently obtained a large amount of Sodium Chlorate, and have been looking for some use for it - aside from pyrotechnics. I like the idea of using it for some kind of organic reaction, but it doesn't seem to have many uses in organic chemistry.. After a bit of searching, the only interesting use I could find was NaClO3/HCl being used to selectively chlorinate ketones..

    Any others ideas of organic syntheses which use NaClO3 a a reagent? Maybe oxidation of benzyl alcohol to benzaldehyde.. would that be possible with chlorate?

    Cheers folks,

    karlos³ - 27-9-2019 at 14:44

    I want to do a chiral resolution on methylbenzylamine.
    However, I do not want to use a fractional crystallisation but I want to apply a selective extraction using monosodium tartrate in a two-phase system of toluene and water.
    Like this here: https://erowid.org/archive/rhodium/chemistry/amphetamine.res...
    I already applied that successfully on the amine used in there, and since it was easier and quicker, I would like to use it on 1-PEA too.
    Any objections?

    artemov - 24-10-2019 at 02:24

    Question

    Is lye (for soap making) NaOH or NaOH.H2O? Should I factor in the H2O when calculating stoichiometry?

    According to wiki, "The commercially available "sodium hydroxide" is often this monohydrate".

    [Edited on 24-10-2019 by artemov]

    artemov - 24-10-2019 at 02:32

    Question

    Is 70%-80% sulfuric acid any useful for making esters, ethers, nitric acid (from nitrates), nitrating mixture, and removing thiophenes from toluene? What about dehydration works like drying bromine?

    I have some battery acid and only able/dare to boil it down til 70-80%.

    [Edited on 24-10-2019 by artemov]

    teodor - 24-10-2019 at 04:17

    Quote: Originally posted by artemov  
    Question

    Is lye (for soap making) NaOH or NaOH.H2O? Should I factor in the H2O when calculating stoichiometry?

    According to wiki, "The commercially available "sodium hydroxide" is often this monohydrate".

    [Edited on 24-10-2019 by artemov]


    I did titration to check that, and now I know that some specific brand (De Parel) available on Dutch market is perfectly dry. It looks like small globules.

    [Edited on 24-10-2019 by teodor]

    Metacelsus - 24-10-2019 at 06:46

    Quote: Originally posted by artemov  
    Question

    Is 70%-80% sulfuric acid any useful for making esters, ethers, nitric acid (from nitrates), nitrating mixture, and removing thiophenes from toluene? What about dehydration works like drying bromine?

    I have some battery acid and only able/dare to boil it down til 70-80%.


    Generally yes, although for nitrating mixture it might not work as well.

    karlos³ - 3-11-2019 at 09:58

    I found this method here for the deprotection of N-alkyl phthalimides to the primary amine: https://www.organic-chemistry.org/abstracts/literature/523.s...
    Would it work with N-alkyl saccharin too?

    Cou - 4-11-2019 at 18:43

    Has anyone been able to make acetyldehyde from readily available chemicals?

    Tellurium - 10-11-2019 at 14:51

    Quote: Originally posted by Cou  
    Has anyone been able to make acetyldehyde from readily available chemicals?

    I don't know if KMnO4 is readily available for you, but I think you should be able synthesizing it by dripping EtOH in a warm/hot acidified KMnO4 solution and distilling of the Aldehyde right away. Boiling point of acetaldehyde is just 20°C, so a lot of it should escape before being oxidized to Acetic acid.

    Tellurium - 10-11-2019 at 14:56

    Well I Just cleaned a really messed up flask with H2SO4/CrO3.
    The stir bar was White before(and told to be PTFE coated) and now it is completely black. Did this happen to someone before? Because I thought PTFE was inert to this and with other stirbars this did not happen at all. Or did I maybe get ripped of with a few of my stir bars?:o

    IMG_20191110_234232.jpg - 4.1MB

    j_sum1 - 23-11-2019 at 19:31

    My hardware store hydrochloric acid seems to be contaminated with Ti (of all things).
    It gives a pale purple / lilac cloudy hue when reacting with zinc or magnesium.
    It forms a bright orange complex with a very small of dilute peroxide.

    Or is there something else that would give this same set of results?
    How would titanium contamination even happen?

    Decibel meters

    Morgan - 4-12-2019 at 11:29

    Any thoughts on buying a decibel meter, what weaknesses or drawbacks come into play or best buy on eBay? There're some for 15 dollars or so supposedly very accurate.

    Sulaiman - 4-12-2019 at 15:13

    Commercial decibel meters have (or did have in my time) selectable weighting curves and most importantly, they were calibrated.
    Calibrated equipment allows 'legal' measurements (in my case noise levels in train cabins),
    a cheap or diy sound level meter could be technically as good or even superior,
    but it would not be acceptable for commercial monitoring purposes.

    A sound level meter is a fairly simple device,
    it is the calibration that is important.

    G-Coupled - 4-12-2019 at 15:20

    Quote: Originally posted by Morgan  
    Any thoughts on buying a decibel meter, what weaknesses or drawbacks come into play or best buy on eBay? There're some for 15 dollars or so supposedly very accurate.
    If you've a half decent smartphone, look for any number of free apps which use your phone's hardware to act as a decibel meter.

    Some of them seem to work pretty well.

    Morgan - 5-12-2019 at 10:37

    Thanks for those thoughts all. I was reading some of the complexities of measuring sound on Wiki. This was interesting too.

    "However, the reading from a sound level meter does not correlate well to human-perceived loudness, which is better measured by a loudness meter. Specific loudness is a compressive nonlinearity and varies at certain levels and at certain frequencies.These metrics can also be calculated in a number of different ways."
    https://en.wikipedia.org/wiki/Sound_level_meter

    Sulaiman - 5-12-2019 at 19:27

    Accoustics and auditory perception is a complex area,
    accoustics and especially sonar were the key topics of some of my lecturers and their post-grad researchers,
    about 30 years ago I was designing, building and selling (small private sales) 'Hi-Fi' equipment,
    one of the important areas is perceived loudness
    https://en.wikipedia.org/wiki/Equal-loudness_contour
    but the most complex is Psychoacoustics
    https://en.wikipedia.org/wiki/Psychoacoustics
    (I can discuss this topic ad nauseum)

    What is the intended use for the sound level meter ?

    Morgan - 6-12-2019 at 10:56

    I wanted to know the level of sound some of my smallish jam jar jets make with exhaust tubes attached which increases the robustness enough so that I wear hearing protection - just hot gases going in and out a single orifice somewhat fast.

    This sort of thing as an example.
    https://www.youtube.com/watch?v=T-EoSOfaplo

    j_sum1 - 9-1-2020 at 01:32

    Quote: Originally posted by j_sum1  
    My hardware store hydrochloric acid seems to be contaminated with Ti (of all things).
    It gives a pale purple / lilac cloudy hue when reacting with zinc or magnesium.
    It forms a bright orange complex with a very small of dilute peroxide.

    Or is there something else that would give this same set of results?
    How would titanium contamination even happen?


    Bumping this since the exact same question with the same product has come up with another user. I think Ti is the most likely culprit: nothing else I know fits the symptoms. But how would Ti have gotten in there? Seems a mystery.

    sodium bichloride (say what?)

    j_sum1 - 9-1-2020 at 01:57

    My latest project has been installing a small swimming pool. It is filling as I type. (Yay! Relief from the aussie heat!)
    It comes with a couple of manuals that appear to have been kludged together from a range of models and passed through at least one poor translation process. It is a bit unclear to say the least.
    When it comes to the section(s) on chemicals to maintain correct water chemistry, there is a mountain of conflicting and contradictory information. It mentions sodium dichloroisocyanuric acid. It also mentions bromine in one place. It has an ozone generator and so mentions that. It recommends monopersulfate. But the bulk of the instruction centres around "sodium bichloride". I am wondering what on earth is meant by that.

    Any insights? It is clearly an inappropriate name for something. But what? Does anyone know of any pool chemicals that are commonly misnamed as sodium bichloride?

    woelen - 9-1-2020 at 02:57

    The only one I can think of is sodium hypochlorite. Where I live, we can buy big jugs (10 liters, or even 20 liters) of 12.5% active chlorine (solution of NaOCl in water). This is poured in a swimming pool for chlorinating purposes. Sometimes it is combined with cyanuric acid in order to stabilize the chlorine. This is important for outdoors swimming pools in full sunshine, which otherwise suffer from rapid decomposition of the hypochlorite to chloride and oxygen by UV-light.

    karlos³ - 9-1-2020 at 04:38

    Maybe they meant sodium bisulfate, which is a common pH-down pool chemical?

    wg48temp9 - 9-1-2020 at 08:32

    Quote: Originally posted by j_sum1  
    My latest project has been installing a small swimming pool. It is filling as I type. (Yay! Relief from the aussie heat!)
    It comes with a couple of manuals that appear to have been kludged together from a range of models and passed through at least one poor translation process. It is a bit unclear to say the least.
    When it comes to the section(s) on chemicals to maintain correct water chemistry, there is a mountain of conflicting and contradictory information. It mentions sodium dichloroisocyanuric acid. It also mentions bromine in one place. It has an ozone generator and so mentions that. It recommends monopersulfate. But the bulk of the instruction centres around "sodium bichloride". I am wondering what on earth is meant by that.

    Any insights? It is clearly an inappropriate name for something. But what? Does anyone know of any pool chemicals that are commonly misnamed as sodium bichloride?


    Perhaps if you gave more context by posting the relevant section of the instructions it may be obvious what chemical they are referring to.

    If the instructions are unclear and conflicting why not ignore them. There is lots of info on the web about maintaining the chemistry of a swimming pool. I would think if you are going to use the ozone generator you will have to pick a chemistry that's compatible with that.

    j_sum1 - 9-1-2020 at 14:12

    Clearest statement anywhere in the manual:
    Quote:
    We recommend using chlorine particles of sodium bichloride for water disinfection, because sodium bichloride can be completely and rapidly dissolved in water and its PH value is close to neutral.

    The most likely candidate would be Na-DCCA. Sodium salt with two chlorines so the name fits. Soluble solid with little affect on pH.

    You are correct: I am not going to rely on the manual since it is so unclear. But it was important to read anyway. I do need to select a treatment process compatible with materials used in the pool. I have read a few online guides as well. I am happy with the chemical theory. I am not happy with some of the terminology and descriptions given. And I am trying to get my head around quantities. All the guides refer to "total alkalinity" measured in ppm as separate from pH. I would much prefer molar concentration of carbonate if that is what is meant. I have read some truly shocking descriptions of chemical equilibrium. Fortunately there is some good information amidst all the crap out there.

    arkoma - 9-1-2020 at 14:37

    The Mandarin to English translator strikes again

    *edit* pulled some generic acetaminophen by refluxing the pills in acetone. The damn stuff xtallized this weird reddish color. Any thoughts?



    IMG_20200109_164103.jpg - 987kB

    [Edited on 1-9-2020 by arkoma]

    CharlieA - 9-1-2020 at 18:46

    Did you use pills that may have contained a red dye? Perhaps the dye was adsorbed on the crystals. You could try treating your acetone solution with activated carbon to remove the dye before the crystallization step. Also, washing the crystals on the filter with acetone may remove the dye, assuming that it is adsorbed onto the crystals of product.

    yobbo II - 22-1-2020 at 16:12

    Does anyone know where I can get a datasheet for a R450 photo multiplier tube.

    TIA,
    Yob

    Abromination - 26-1-2020 at 11:07

    Can sodium sulfate be used instead of potassium sulfate to precipitate neodymium and iron as a double sulfate salt?
    Thanks

    clearly_not_atara - 29-3-2020 at 11:49

    A lot of sources say that phenylacetic acids are especially prone to decarboxylation. However, I've had trouble finding any published reports describing this decarboxylation under ordinary conditions. There are some papers about gas-phase decarboxylation, papers in supercritical water, papers using UV-C photodecarboxylation, etc. I've heard the vinylogy explanation but experimentals, kinetics etc are hard to find since you just get a bunch of recent papers using this or that catalyst for decarboxylative whatever.

    In particular, the simple decarboxylation of naproxen to 2-methoxy-6-ethylnaphthalene is widely reported as an undesired side-reaction, but if you search for references you get a bunch of catalytic oxidative decarboxylations which give the wrong product and are overcomplicated. I did find this:

    https://pubs.acs.org/doi/10.1021/jp805614y

    although at this point it might be faster to just CWE some Aleve and leave it out in the sun to see what happens

    Abromination: this double salt is called "eldfellite", the data page describes it as "water-sensitive". i don't know a damn thing about neodymium. however, sodium generally does not do as good a job as potassium when it comes to precipitating highly symmetric anions like ClO4-, IO4-, or in this case Fe(SO4)2-. I don't know a damn thing about neodymium, unfortunately.

    https://www.mindat.org/min-35791.html

    [Edited on 29-3-2020 by clearly_not_atara]

    Tsjerk - 1-4-2020 at 07:56

    I found some 2,2-bipyridine! Some ideas to do some nice coordination chemistry with it?

    clearly_not_atara - 1-4-2020 at 14:32

    It forms lots of copper complexes, which are apparently good Ullmann reaction catalysts and can also catalyze the dehydrogenation of alcohols with atmospheric oxygen.

    clearly_not_atara - 12-4-2020 at 10:18

    Does the Sandmeyer reaction work for alkyl fluorides with alkali nitrite and hydrofluoric acid? All I can find with Google are a bunch of sites mentioning that it doesn't work well for aryl fluorides, but copper is not required for the alkyl Sandmeyer reaction, so that doesn't tell me very much.

    Lion850 - 13-4-2020 at 02:42

    I tried to process lead-tin solder into iodides. The lead went well, but the tin nearly all ended up as a very fine white powder which I assume is tin (iv) oxide SnO2. This powder seems very unreactive. It did not dissolve in room temperature HCl. With very hot H2SO4 I got a charcoal coloured substance which seems inert. Any suggestions how SnO2 can be processed into other tin salts?

    mackolol - 20-4-2020 at 01:29

    Hey, I have short question. Is it better (for glass or in general) to apply vacuum to distillation setup when it is fully heated, or to apply it at the beginning and then heat along with vacuum?

    [Edited on 20-4-2020 by mackolol]

    Sulaiman - 20-4-2020 at 03:45

    Apply vacuum first then heat,
    if you heat first, when you apply vacuum there is a good chance of violent boiling.

    fusso - 20-4-2020 at 03:56

    Quote: Originally posted by Sulaiman  
    Apply vacuum first then heat,
    if you heat first, when you apply vacuum there is a good chance of violent boiling.
    You forgot that the heat would also increase the pressure causing an explosion.

    mackolol - 20-4-2020 at 08:28

    Quote: Originally posted by Sulaiman  
    Apply vacuum first then heat,
    if you heat first, when you apply vacuum there is a good chance of violent boiling.


    But is there any other disadvantage beside too violent boiling? (maybe glassware damage)

    Quote: Originally posted by fusso  
    You forgot that the heat would also increase the pressure causing an explosion.


    Ah, right

    Has anyone checked the 'accuracy' of cheap Chinese pH papers ?

    Sulaiman - 25-4-2020 at 04:20


    mackolol - 25-4-2020 at 05:36

    I'm using ones and they work quite well for my purposes, but the scale isn't very precise..

    karlos³ - 30-5-2020 at 23:33

    The chemoluminescence reaction with NaBH4 and KMnO4 is known I would guess?
    I would like to try it soon, but the reaction also calls for sodium hexametaphosphate which I don't have.

    But why is that stuff involved?
    I don't understand it, because actually, it is not really involved:
    NaBH4 + Mn(III, IV or VIII)/H+→ products + Mn(II)*→ Mn(II) + light (~690nm)

    What does this salt do in there? Is it needed?
    Can it be replaced, if so, what can I use as replacement?
    I read up on that, and besides it seems that it can be substituted with sodium orthophosphate, and that it is only in there because it affects the wavelength.

    What would be a good replacement? I have no phosphorus acid, neither its salts.
    chemplayer uses phosphoric acid, instead of the sulfuric, is it just for acidification used, or does it affect the wavelenght as well?
    Only P-containing substance I can offer would be some sodium hypophosphite.

    Can someone help? I would really love to try it, but I'm just not sure if it is even worthwhile under these circumstances.

    wg48temp9 - 31-5-2020 at 08:58

    Quote: Originally posted by karlos³  
    The chemoluminescence reaction with NaBH4 and KMnO4 is known I would guess?
    I would like to try it soon, but the reaction also calls for sodium hexametaphosphate which I don't have.

    But why is that stuff involved?
    I don't understand it, because actually, it is not really involved:
    NaBH4 + Mn(III, IV or VIII)/H+→ products + Mn(II)*→ Mn(II) + light (~690nm)

    What does this salt do in there? Is it needed?
    Can it be replaced, if so, what can I use as replacement?
    I read up on that, and besides it seems that it can be substituted with sodium orthophosphate, and that it is only in there because it affects the wavelength.

    What would be a good replacement? I have no phosphorus acid, neither its salts.
    chemplayer uses phosphoric acid, instead of the sulfuric, is it just for acidification used, or does it affect the wavelenght as well?
    Only P-containing substance I can offer would be some sodium hypophosphite.

    Can someone help? I would really love to try it, but I'm just not sure if it is even worthwhile under these circumstances.


    You should read the following paper:
    Attachment: Mechanism-Permanganate-Chemiluminescence-hindson2010.pdf (436kB)
    This file has been downloaded 61 times

    Apparently polyphosphate ions complex Mn3+ which increases the chemoluminescence 50 fold. The correct ph is also required.

    Interestingly phenols and ascorbic acid can be used in place of the NaBH4.

    mayko - 31-5-2020 at 11:53

    You might be interested in this too (same first author)


    Hindson, C. M., Smith, Z. M., Barnett, N. W., Hanson, G. R., Lim, K. F., & Francis, P. S. (2013). Autocatalytic Chemiluminescence Sheds New Light on the Classic Permanganate–Oxalate Reaction. The Journal of Physical Chemistry A, 117(19), 3918–3924. https://doi.org/10.1021/jp312603m




    Attachment: Hindson et al. - 2013 - Autocatalytic chemiluminescence sheds new light on the classic permanganate-oxalate reaction.pdf (1.6MB)
    This file has been downloaded 65 times


    karlos³ - 31-5-2020 at 17:26

    Thank you both very much! :)

    karlos³ - 18-6-2020 at 06:06

    I need some dimethylamine freebase, and I have DMF, can I hydrolyse it with base simply at RT?0
    That would be very practical for me, giving me a solution I can use directly as it is for the reductive amination I intend to use it for.
    If not, I guess I have to go via the HCl hydrolysis instead.

    stoichiometric_steve - 18-6-2020 at 12:24

    Quote: Originally posted by karlos³  
    I need some dimethylamine freebase, and I have DMF, can I hydrolyse it with base simply at RT?0
    That would be very practical for me, giving me a solution I can use directly as it is for the reductive amination I intend to use it for.
    If not, I guess I have to go via the HCl hydrolysis instead.


    Why not hydrolyze with NaOH with heating, driving off the Dimethylamine through a drying column and collecting it in chilled MeOH until saturated?

    karlos³ - 18-6-2020 at 12:37

    Because the smell lingers :D
    Well guess I rather go via the HCl hydrolysis.
    Its better and easier stored this way.
    My ketone is a hydroxyketone as you well know, and so it will form an imine very readily and a stable one even.

    stoichiometric_steve - 26-6-2020 at 15:37

    Quote: Originally posted by karlos³  
    Because the smell lingers :D
    Well guess I rather go via the HCl hydrolysis.
    Its better and easier stored this way.
    My ketone is a hydroxyketone as you well know, and so it will form an imine very readily and a stable one even.


    You have a point there, but i think a solution in MeOH would be way more versatile, and if set up correctly, you won't even have to deal with any fumes whatsoever.

    Belowzero - 3-7-2020 at 04:48

    After the whole corona thing dies down I expect the market to be flooded by used cheap plexiglass , perhaps even free.
    While looking for fumehood designs I stumbled across designs that are made entirely out of plexiglass , although not the most important feat. it looks really slick.
    Relatively easy material to work with and not too heavy.

    Now I wonder if this material is resistant enough to withstand at least a few years of abuse?
    I could coat the parts exposed to the highest airflow volume with say epoxy/paint to make it more resilliant.


    [Edited on 3-7-2020 by Belowzero]

    Σldritch - 5-7-2020 at 12:24

    How much space do i need for GAMESS, macmolplt and avogadro? I want to look at orbitals of up to maybe 30 atom clusters and only have 30Gb. Do i even have enough space for all the programs?

    karlos³ - 30-7-2020 at 14:40

    How reliable is this patent regarding the reductive amination of napthylglyoxyl hydrate?
    Can aldehyde hydrates be reductively aminated like this? Never saw another example of it so far.
    The patent is United States Patent Office 3,463,808, like look at example 13.
    Or, United States Patent Office 3,312,733, example 9.
    What do you guys think? I'm trying to run a reductive amination of 2-naphthylglyoxyl hydrate right now, but I am not so confident it will work.
    Still in the process of aldimine formation.

    karlos³ - 31-7-2020 at 11:51

    Sadly, it didn't seem to work so far.
    I still have to work it up properly, but after an acidic quench way too much oil fell out, indicating my substrate hasn't reacted to an amine as intended.

    Can someone shoot an opinion about these doubtful patents please?

    LuckyWinner - 8-8-2020 at 01:25

    i dried my calcium chloride dehydrate inside an old iron pan with some minor rust on the stove.

    my CaCl appears dry but it now has a slight reddish , (iron oxide?) tint.

    will this cause any trouble when drying diethyl ether for example or other solvents?

    how can I clean my CaCl from the rust contamination?

    Sulaiman - 20-8-2020 at 03:07

    I want to make chloroform via the haloform reaction but I am presently unable to cool the bleach so
    can I add acetone to RT bleach a little at a time over an extended period?
    E. G. 5L 6% sodium hypochlorite plus acetone in 10ml portions over several hours to allow cooling.
    and
    acetone bp=56C, how high can I allow the temperature of the mixture to get without significant losses?

    j_sum1 - 20-8-2020 at 04:38

    Quote: Originally posted by Sulaiman  
    I want to make chloroform via the haloform reaction but I am presently unable to cool the bleach so
    can I add acetone to RT bleach a little at a time over an extended period?
    E. G. 5L 6% sodium hypochlorite plus acetone in 10ml portions over several hours to allow cooling.
    and
    acetone bp=56C, how high can I allow the temperature of the mixture to get without significant losses?

    No expert. I have only done it a few times.
    I have always heard that you need to keep temp brlow 20C during the reaction and that NaOH byproduct causes chloroform to decompose. Both of these would suggest problems with what you propose.
    Can't you buy a bag of ice?

    S.C. Wack - 20-8-2020 at 13:58

    The only time anyone does it (edit: should do it) cold is when they are trying to do it without glassware.

    [Edited on 21-8-2020 by S.C. Wack]

    Sulaiman - 20-8-2020 at 21:31

    I tried 5L of 5.5% NaOCl with 200ml acetone at RT (c30oC)
    here is a view of the crude product :
    yield.jpg - 30kB

    A yield of 3.7% :(
    ____________________________________________________
    I am fairly confident that the bulk of the remaining available chloroform (estimate >60ml) is dissolved in the 5L of water.
    I may try distilling the 5L solution sometime later to see what I can recover.
    _____________________________________________________
    Judging by smell (which is not quantitive) there was significant evaporation of chloroform during the experiment.
    ... 200ml of chloroform lost to the 5L solution and the environment :(
    ______________________________________________________

    Do not waste effort trying this at home :)
    ===============================================
    next: playing with tcca per this thread and links http://www.sciencemadness.org/talk/viewthread.php?tid=5686

    Jimmymajesty - 1-9-2020 at 13:14

    Is there an easy way to convert N'N'diethyl hydroxylamine back to hydroxylamine? Thanks for your help!

    solo - 8-9-2020 at 09:04

    What is this piece used for....some type of trap .?......solo

    5E578C39-EA28-4B4D-946F-BE9D527C218D.jpeg - 1.8MB

    RogueRose - 8-9-2020 at 15:57

    Quote: Originally posted by Sulaiman  
    I tried 5L of 5.5% NaOCl with 200ml acetone at RT (c30oC)
    here is a view of the crude product :


    A yield of 3.7% :(
    ____________________________________________________
    I am fairly confident that the bulk of the remaining available chloroform (estimate >60ml) is dissolved in the 5L of water.
    I may try distilling the 5L solution sometime later to see what I can recover.
    _____________________________________________________
    Judging by smell (which is not quantitive) there was significant evaporation of chloroform during the experiment.
    ... 200ml of chloroform lost to the 5L solution and the environment :(
    ______________________________________________________

    Do not waste effort trying this at home :)
    ===============================================
    next: playing with tcca per this thread and links http://www.sciencemadness.org/talk/viewthread.php?tid=5686


    Was your bleach new? I've heard of low yields from using old NaOCl. Did you chill the bleach and the acetone before mixing the two?

    RogueRose - 8-9-2020 at 16:02

    Well you kind of cut off the bottom of the picture, is it just sealed glass at the bottom? Also, does the tube from the top & middle section seal to the bottom tube, or is it open at the bottom?

    solo - 8-9-2020 at 17:16

    sealed at the bottom with a small hole on the upper side...and open on top ....solo

    [Edited on 9-9-2020 by solo]

    [Edited on 9-9-2020 by solo]

    IMG_3748.JPG - 48kBIMG_3747.JPG - 40kBIMG_3749.JPG - 43kBIMG_3750.JPG - 53kBIMG_3751.JPG - 54kBIMG_3752.JPG - 48kB

    CharlieA - 9-9-2020 at 17:03

    Just a WAG (as opposed to a SWAG): could this be some kind of device to deliver 10 mL of a reagent from some kind of reservoir?

    B(a)P - 11-9-2020 at 02:34

    Some time ago I purchased a cheap condenser and it came with an addition funnel. I used the addition funnel for the first time today and it was almost impossible to get a constant drip rate. Can I replace the tap to get something usable, any tips for getting crappy taps to perform or do I just forget it?

    clearly_not_atara - 11-9-2020 at 04:39

    Quote: Originally posted by S.C. Wack  
    The only time anyone does it (edit: should do it) cold is when they are trying to do it without glassware.

    For the reaction this is true, but in order to achieve the best phase separation at workup you want the solution to be just barely above freezing IIRC

    paulll - 12-9-2020 at 19:53

    Has anybody ever heard of such a thing as a spring-loaded flask clamp? With how handy it would be for receiving flasks it seems to be a thing that should exist and yet I don't see any anywhere.

    karlos³ - 12-9-2020 at 22:42

    Quote: Originally posted by paulll  
    Has anybody ever heard of such a thing as a spring-loaded flask clamp? With how handy it would be for receiving flasks it seems to be a thing that should exist and yet I don't see any anywhere.

    Could you draw one, just a bad sketch to get the idea?
    I'm not sure how that should look like.

    I hope not like that: https://www.sigmaaldrich.com/content/dam/sigma-aldrich/produ...
    Because that would mean they stole and produced your idea, and that in merely hours!
    Those capitalist pigs, no respect on your intellectual property! :o

    But seriously, like that?
    Because initially I imagined a clamp to hold the receiving flask connected with the vacuum adapter(or cow) or such.
    Just a plain flask clamp.
    Only that I can't picture how such a thing would look like spring-loaded, which is why I was asking for a sketch of it.
    And promised, not to steal the idea and sell it to sigma or whoever bids most, you have my hobby chemist word of honor on that! :D

    paulll - 13-9-2020 at 18:26

    Notwithstanding the fact that I can't draw with or without a computer... something like this. I'm thinking, e.g., for the receiving flask in a distillation rig - or any other flask that you'd want to change out mid-experiment.
    So instead of tightening a thumbscrew to apply pressure to the piece, you'd be unscrewing it to release spring tension onto it, to hold it in place. The flask could then be removed and replaced by squeezing the other end of the clamp scissors-style. If that makes sense lol


    Untitled 1.png - 12kB

    [Edited on 14-9-2020 by paulll]

    Morgan - 29-9-2020 at 07:54

    Does anyone know a company that makes these cylindrical volumetric flasks?

    https://i.ebayimg.com/images/g/QqkAAOSwg35atCrz/s-l1600.jpg
    https://i.ebayimg.com/images/g/GLsAAOSwuHZatCr0/s-l1600.jpg

    Antigua - 29-9-2020 at 08:02

    Quote: Originally posted by Morgan  
    Does anyone know a company that makes these cylindrical volumetric flasks?

    https://i.ebayimg.com/images/g/QqkAAOSwg35atCrz/s-l1600.jpg
    https://i.ebayimg.com/images/g/GLsAAOSwuHZatCr0/s-l1600.jpg

    https://www.wilmad-labglass.com/
    Here - I found them through a simple search, but they do look very expensive.

    [Edited on 29-9-2020 by Antigua]

    Morgan - 29-9-2020 at 15:22

    Quote: Originally posted by Antigua  
    Quote: Originally posted by Morgan  
    Does anyone know a company that makes these cylindrical volumetric flasks?

    https://i.ebayimg.com/images/g/QqkAAOSwg35atCrz/s-l1600.jpg
    https://i.ebayimg.com/images/g/GLsAAOSwuHZatCr0/s-l1600.jpg

    https://www.wilmad-labglass.com/
    Here - I found them through a simple search, but they do look very expensive.

    [Edited on 29-9-2020 by Antigua]


    I see some cylindrical volumetric flasks there but not the identical shape. There are also square volumetric flasks I found that are close to it in proportion such as this one.
    https://www.gogenlab.com/lab-supplies/flasks/volumetric-flas...
    Just now found it.
    https://kinesis.co.uk/dissolution-900ml-volumetric-flask-wit...

    Morgan - 2-10-2020 at 07:01

    Quote: Originally posted by Morgan  
    Quote: Originally posted by Antigua  
    Quote: Originally posted by Morgan  
    Does anyone know a company that makes these cylindrical volumetric flasks?

    https://i.ebayimg.com/images/g/QqkAAOSwg35atCrz/s-l1600.jpg
    https://i.ebayimg.com/images/g/GLsAAOSwuHZatCr0/s-l1600.jpg

    https://www.wilmad-labglass.com/
    Here - I found them through a simple search, but they do look very expensive.

    [Edited on 29-9-2020 by Antigua]


    I see some cylindrical volumetric flasks there but not the identical shape. There are also square volumetric flasks I found that are close to it in proportion such as this one.
    https://www.gogenlab.com/lab-supplies/flasks/volumetric-flas...
    Just now found it.
    https://kinesis.co.uk/dissolution-900ml-volumetric-flask-wit...


    I noticed this 2 liter size is listed for $210.89 and probably shipping costs. I decided to buy that shape having found 4 of them (same Kimble 28040 flask) for sale for $34.25 each or best offer on eBay, new old stock so I bought one along with free shipping. The square flask is 5 X 5 X 18 inches.
    https://www.gogenlab.com/lab-supplies/flasks/volumetric-flas...

    [Edited on 2-10-2020 by Morgan]

    j_sum1 - 18-10-2020 at 16:56

    Anyone able to give any enlightenment as to what this reaction is?
    https://www.youtube.com/watch?v=cVxySCgUy8A

    I thought it was a stunning demo and one I would love to add to my repertoire.
    CoCl2 I have. But what is the reaction mixture being used? And what kind of complexing causes the green?

    DraconicAcid - 18-10-2020 at 17:19

    Quote: Originally posted by j_sum1  
    Anyone able to give any enlightenment as to what this reaction is?
    https://www.youtube.com/watch?v=cVxySCgUy8A

    I thought it was a stunning demo and one I would love to add to my repertoire.
    CoCl2 I have. But what is the reaction mixture being used? And what kind of complexing causes the green?


    Might be basic peroxide and carbonate? Or basic peroxide and oxalate?

    B(a)P - 18-10-2020 at 19:02

    https://uwaterloo.ca/chem13-news-magazine/march-2014/activities/sharing-chemistry-community-colorful-catalyst

    I think this is what you are after.


    j_sum1 - 18-10-2020 at 19:23

    Quote: Originally posted by B(a)P  
    https://uwaterloo.ca/chem13-news-magazine/march-2014/activities/sharing-chemistry-community-colorful-catalyst

    I think this is what you are after.


    Awesome. that is just great!

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