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Posts posted by UC

  1. Well yeah, water would screw with yield, resulting in some incompletion, and thus acetone formation, but I suppose the reaction will still occur to a reasonable extent, right? :-(


    No. You won't make any aluminum isopropoxide. Instead you'll make aluminum hydroxide until you run out of water, but Al(OH)3 is voluminous, so you probably would have sludge as your reaction mixture.



    Nevermind, I just looked at the structural formulas of acetaldehyde and formaldehyde. If it is so, wouldn't propionaldehyde, be able to participate in the canizzaro reaction?


    Look at the drawing below. From left to right, I have drawn formaldehyde, benzaldehyde, neopentaldehyde, acetaldehyde, propionaldehyde, and cyclohexanal (formylcyclohexane).


    The alpha carbon is the carbon adjacent to the aldehyde carbonyl carbon. If the alpha carbon has no hydrogens (alpha-hydrogens) on it, the cannizzaro reaction will occur, with no condensation products.


    For formaldehyde, there is no alpha carbon at all, so it's good to go for cannizzaro.

    For benzaldehyde, the alpha-carbon is part of the aromatic ring, and has no hydrogens.

    For neopentaldehyde, the alpha-carbon is quaternary and has no hydrogens.


    Acetaldehyde, propionaldehyde, and cyclohexanal all have at least one alpha hydrogen, and are therefore capable of undergoing keto-enol tautomerism. Thus, they are capable of forming enolates, which participate in the aldol reaction/condensation.


    There is ALWAYS an equilibrium present, but sometimes it lies so far to one side of the reaction that it effectively goes to completion. Aluminum isopropoxide is picky about which things it reduces. I'm not sure it would even work on acetaldehyde, but some research on standard enthalpies of formation should tell you the answer.


  2. Magnesium is an alkaline earth metal and will happily react with water to generate hydrogen.


    I think this is because the copper is laid down on the magnesium and forms a galvanic cell, which should predispose the magnesium to rapid reaction in water


    If you put some aluminum foil in saturated NaCl brine, you get no reaction. but it is rather vigorous upon the addition of a catalytic amount of copper salt. This is the same principle, and credit to Woelen for the experiment.

  3. Not quite. You see, this is what happens, the potassium hydroxide donates a hydroxyl group to the aldehyde, as such, the bond structure of the aldehyde shifts, and the oxygen that was formerly double bonded, is only single bonded, due to the bonding of the OH. As such, the oxygen is negatively charged.


    By nature, this configuration, as an end product is unstable, and this intermediary gives off an oxygen, to oxidise present aldehyde, generating a carboxylic acid, while the first aldehyde/ former intermediary, having lost an oxygen, and gained a hydroxyl group, is now an alcohol.


    Furthermore, given the basic environment, the potassium hydroxide, reacts with the acid, to form sodium acetate. I understand the confusion; it is a bit of a non- standard reaction really. Here's a link with pretty pictures, which I think would greatly help...




    The Cannizarro reaction is only applicable to aldehydes that cannot undergo keto-enol tautomerism. The best known of these are benzaldehyde and formaldehyde. With acetaldehyde you will mainly get aldol reaction and aldol condensation products plus an enjoyable amount of tar.


    Salt will not generate anhydrous isopropanol. It will get you to 91% and no better. Take the 91%, shake with 10% of it's weight in NaOH flakes, remove the aqueous layer. Repeat with another small amount of NaOH, and distill to give an effectively anhydrous product. If you want better, use a little sodium metal and redistill in flame-dried glass.


    I can dig up the reference if you'd like.


    Also, proper nomenclature is aluminum isopropoxide.

  4. It is more likely that the fallowing will occur then that it will yield chlorine.

    NaOCL + H202 -> NaCl + H2O + O2


    Hence my use of "some."


    If you intend this as a means to neutralize bleach, then the production of any chlorine gas is unacceptable. Go try it. I guarantee the fumes coming off are not just oxygen.

  5. I learned on this forum that if one wants to neutralize bleach one can add hydrogen peroxide. Useful if one wants to clean up after a bleach spill or clear a washing machine in a laundromat with oxyclean before putting their clothes in. The post said that one gets salt, water, and oxygen.


    My question, is this an endothermic, exothermic, or neutral reaction. Would it be safe to rinse ones hands in H2O2 after using NaOCl, or is one risking harm?


    Perhaps in theory, but bleach mixed with hydrogen peroxide will also make some chlorine gas.

  6. Classically you convert it to a grignard reagent then add water.

    Doesn't work with fluorides.


    I can't believe I forgot this one. This isn't tolerant of beta-haloethers though, which undergo elimination (see the Boord olefin synthesis), or of hydroxy groups, or other non-LiAlH4 responsive functional groups that do react with grignards.

  7. LiAlH4 reduces primary and secondary alkyl halides to the alkanes, and in some cases tertiary alkyl halides.


    assuming the structure is relatively simple and insensitive, you could dehydrohalogenate the tertiary alkyl halide and then hydrogenate it over Pd/C. (palladium on carbon)


    Googling around also found me some stuff on tributyltin hydride with catalytic InCl3, which seems to occur via a radical mechanism.

  8. Hmm...copper is below hydrogen in the activity series, right? Would hydrogen react with copper salts (like sulfate) to form the corresponding acid?


    In theory yes, but it's worthless in practice as hydrogen reductions of metal compounds need to be carried out in furnaces to get them to work.

  9. its not so much to do with heat transfer as the temperature remains pretty constant throughout the process(the heat has plenty of time to transfer to the center). although it will play a role, just not as significant as raising the temperature to get faster denaturing of the proteins.


    Very little protein to speak of ;)


    Perhaps gelatinization of starches is what you're looking for.

  10. I suggest you learn what the hell you're doing first. Don't touch organic chem, especially chlorinations, especially lachrimators, especially moisture and air sensitives until you've putzed around with inorganics for a while and then done basic organic stuff. It helps you get a feel for things. Proper glassware and a fume hood costs a fortune. Also, try doing some good old literature search. The original posts shows an incredible amount of ignorance.


    PCl3 cannot be made from red phosphorus at any rate and pool chlorine isn't "chlorine", but can be used to make it.

  11. If you already have sodium you could make the less reactive metals via a termite reaction with their respective salts.

    eg. Na + LiCl -> Li + NaCl

    2 Na + CaCl2 -> 2 NaCl + Ca

    This could be extraordinarily dangerous though, I'm to sure how much heat would be generated. Be careful.



    Also note that if you can somehow obtain the melting point of salts you can generate both group I and II metals by electrolysis of the molten salt.

    eg. CaCl2 -> Cl2 + Ca


    Thermite implies an aluminothermic reaction, which using sodium certainly is not. Lithium is a stronger reducing agent than sodium and lithium has a higher boiling point than sodium, so any attempt to make lithium with sodium is hopeless. You can often distill the product out of a molten bath of say, calcium, which uses Le Chatlier's principle to cheat standard reactivity series.


    Calcium is appreciably soluble in molten CaCl2 and as a result it is produced via some tricky engineering that pulls the forming metal up out of the CaCl2 bath as a rod, to prevent it from dissolving and being reduced at the other electrode.


    As for the original poster, there are better and less stupid ways to get BOOMS than alkali metals. I suggest you take that discussion elsewhere and try and keep your fingers.

  12. I am fairly sure urea is actually a special case. So the reaction of urea with sodium hydroxide is a bit more complex then is described in the article. Urea can be produced produced by the reaction of sodium cyanate (NaOCN) with ammonium chloride.

    NaOCN + NH4Cl -> NH2CONH2 + NaCl

    by adding NaOH to urea you are essentially reversing the process and will get sodium cyanate, ammonia and water.

    NaOH + (NH2)2CO -> NaOCN + NH3 + H2O


    References, if you please.


    Cyanic acid undergoes nucleophilic attack at the carbon by ammonia, followed by tautomerization, yielding urea. Simply adding something like NaOH will not reverse the reaction mechanism.


    The hydrolysis of urea proceeds like normal base-catalyzed amide hydrolysis, giving first sodium carbamate and ammonia. The carbamate readily undergoes a second hydrolysis reaction to give sodium carbonate and another equivalent of ammonia.

  13. I'd actually go out on a limb and say there probably is some sodium in there. That reaction with water is quite too violent for magnesium, I would think. Magnesium is, however, not a stronger reducing agent than sodium at high temperatures. Sodium, however, is volatile and will boil off from the reaction site if enough heat is supplied. Reactivity series can be cheated by Le Chatlier's principle. This heat is probably being provided by the reaction of the hydroxide portion of NaOH with the Mg, forming Na2O, MgO, and H2.


    The flames gushing out of the pot are probably burning hydrogen and some sodium vapor. That pot looks to be aluminum, which is a horrible choice, since it reacts with sodium hydroxide.


    While impressive, the amount of sodium formed is probably very small and and it is finely divided, trapped in the debris. The reaction with water was far too fast for any significant amount of Na to be present.


    Splashing paraffin in is a horrible idea. Anyone who has ever worked with concentrated NaOH knows that it's nasty and molten NaOH, which you could expect to find in the reaction mix will instantly blind you if it gets in your eye and cause some pretty horrible wounds if it gets on your skin. The paraffin is also flammable, which introduces further hazards. A stream of chilled argon would be far superior, but if you can get that, you probably wouldn't be needing to make sodium, especially like this.

  14. My new plan (following suggestion):


    First, as before, I'll add Fe2O3, in order to use up the excess hydrochloric acid, and forming an arbitrary mixture of iron (II) and (III) chloride.



    Hopefully you mean freshly prepared Fe2O3. The pottery grade stuff is calcined and extremely hard to dissolve. If you have pure Fe2O3, you'll only have Fe(III) in the resulting solution.


    You don't want to use up all the excess acid. FeCl3 is stabilized in solution by excess HCl.


    In water, FeCl3 disassociates to HCl and ferric hydroxychlorides. In dilute enough and neutral/basic solution, it proceeds all the way to ferric hydroxide and you get precipitate. Adding extra HCl drives the equilibrium to the left toward FeCl3 (hydrated).

  15. Cuthber- Where do you buy your chicken wire? Around here, what we call chicken wire has holes about 4cmx4cm. Metal mesh also goes by the name "hardware cloth" if that'll help you in your search.

  16. Fe (II) doesn't form complexes, at least not that I've heard of. You'll make lots of hydrous Fe(OH)2 which will oxidize before your eyes to rust. Fe (III) in solution will certainly form Fe(OH)3 of varying degrees of hydration the second ammonia hits it.


    Since NH4Cl decomposes into fumes, you would be quite likely to get iron oxide if an iron ammine complex were heated.


    Fe (II) is a crappy lewis acid. Strong lewis acids tend to be extremely hygroscopic, but crystallizing an anhydrous salt from aqueous solution is not unheard of. I would suspect that it is probably the dihydrate given that water is in relatively short supply in concentrated HCl.


    Bubble chlorine gas through the solution. Instant Fe (III).

    I'd tell you to add H2O2 to a solution of FeCl2 in HCl, but the iron ions catalyze the decomposition of H2O2 and you'll get a lot of hot oxygen and less chlorine than you'd like.

    Adding bleach instead of H2O2 works if you don't have a problem with sodium ion contamination.

  17. While you may look at the thread, and notice its age, just today, I was digging through my chemical "storage room," to find the solution, I had from before, left for months untouched. With much precipitate encrusted on the bottom, I decided to finally clean this ancient mess up, and poured in a generous amount of hydrochloric acid. The solution slowly grew less and less turbid, until it turned a lovely golden colour, almost like honey, and suddenly I realised- iron chloride!


    The precipitate that had looked black was actually brownish iron hydroxide, while the orangish precipitate was iron oxide! Looking back, I realise that I was using a set of electrodes I had bought which were copper- plated iron, :embarass: which needless to say would have yielded little copper salt, but substantially more iron.


    Needless, to say, this unholy mess settled out, my beaker's clean, and I'm hoping to boil down the solution, to reattain some iron chloride crystals, which I'll store for later use.


    You'll need to shield it from oxidation if you want ferrous chloride crystals. FeCl2 oxidizes to Fe(III) ion very easily and if you don't have an excess of HCl around to trap it as FeCl3 and keep it from hydrolysing, you will get nothing but rust.


    If you want FeCl2, degrease some steel wool and throw into concentrated HCl in a covered beaker (It spatters a *lot*). A white powder settles out afterward, which is some form of FeCl2. I'm not sure if this would be anhydrous or a hydrate.

  18. A two-fer:


    <Aerv> I'm bored of WoW, honestly :/ <- It finally happened!!!! The world must be ending.




    <AzurePhoenix> I found your thread on glass stirring rods to be both engaging and stimulating

    <UnintentionalChaos> lol

    <UnintentionalChaos> kinky

    <AzurePhoenix> ... this is rare for me but i cant even muster some form of followup mockery

    * UnintentionalChaos wins

    <AzurePhoenix> this is proof of the evil nature of alcohol

    <UnintentionalChaos> bwahaha

    * AzurePhoenix beats Chaos with a sack of bottles

    <UnintentionalChaos> the pain is worth it

  19. The real question is would that be better or worse than breathing in pure Chlorine, which isn't advisable from experience. :P At least you can spit Sodium out after the chemical burns and then your only left with burning NaOH in your mouth. :doh:


    But the sodium will cause thermal burns as well and you risk a hydrogen explosion...in your mouth.

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