UC

what's the name of the acid formed by oxidation of glycerol anyway? it may have a low boiling point because of dimer formation

Well, dehydration gives acrolein (acrylaldehyde) by tautomerization, and the oxidation product of that would be acrylic acid. Without dehydration there would be so many hydrogen bonding groups available that the boiling point would probably exceed decomposition temperature.

Ozone would just chew glycerol up into CO2 and formaldehyde.

Hi guys, first time posting and I am sure I will be a frequent poster as I am really trying to master this subject material.

 

My question is concerning solvolysis with ethanol:

 

If I mix 2-bromo-2-methylbutane with heated ehtanol (which is a protic solvent correct?) I should produce two products correct?.......The ethanol oxygen replacing the bromine molecule attached to the 2nd carbon as well as the hydrogen attached to the oxygen atom being bonded to the displaced bromine atom? I just want to make sure I am understanding all this for Sn2 and Sn1 reactions.

 

Scott

You have a tertiary alkyl bromide there. Bromide is a so-so leaving group and because it's tertiary, SN2 is never going to happen. Ethanol, being very weakly basic, will promote SN1 type reactions. Because the mixture is being heated, dehydrohalogenation via E1 is the favored reaction. If it were in the cold, SN1 substitution might show up more.

Merged post follows:

you are creating confusion in between two terms :- solvolysis and reaction as they differ a bit .

 

and if i am not wrong then the competing reaction is elimination reaction just because of tertiary carbon .

 

i have one problem which is blundering my CNS . when an alkyl halide is added to alc.KOH , there is an alkene formation. Alcohol is there but no ether formation takes place . how ? why ?

Depends what kind of alkyl halide you're using, and what kind of alcohol is being used. If the halide is primary and a bromide or especially an iodide, one could expect some amount of ether formation. If the alkyl halide is secondary or tertiary, E1 elimination will be the favored reaction path, especially if the mixture is heated strongly.

Someone have an idea of how lowering the ignition point of glycerol?

I'm thinking mixing ionized glycerol with ozone...

 

Regards.

*directs you toward a chemistry book and demands that you make sense*

my god, what a heap of crap.

lock please?

If there is evidence for an intentional shortage of health care workers, to inflate their wages, that would be interesting news! Let's hear it.

always gotta look for the conspiracy theory, eh?

Haha no, they still iodise salt, but if you buy over a certain amount of iodine (i think its 30mg) in any form (elemental, iodide, iodocarbons etc), you get reported to some investigations beaureau cause its used in the red (phosphorus), white (ephedrine) and blue (iodine) process of making methamphetamine.

That's a load. a $1 bottle of 2% iodine tincture has about a gram on iodine in it, IIRC. Now buying a kilo of iodine off ebay is another story, and may well get you reported to some agency or another. Technically, it's not illegal to own at all, in any quantity, though. The same is true with pseudoephedrine cold medicine. It's not illegal, just really sketchy to buy lots of it. The only thing that's truly illegal is making the drugs.

V2O5 really isn't the way to go. I'd say that the folks on sciencemadness (the ones that aren't morons and cooks) are some of the best amateur chemists out there. They've stopped trying to use V2O5 for a reason. It's just not very amenable to scale-down at all, though it works great in a huge plant where you have precise reactor controls and a continuous production system.

Ozone would work, but it's not pleasant to work with either.

Bubbling O2 through SO2/H2SO4 will do nothing. I don't think you make much "pyrosulfuric acid" (maybe a small amount of equilibrium product) so much as a solution of SO3 in H2SO4. The energy barrier for [ce] 2SO2 + O2 -> 2SO3 [/ce] is just too high to overcome without a catalyst.

Perhaps a grignard reagent can be used to add the alkyl chain onto the benzene ring. If you converted the benzene ring into benzaldehyde, isobutylmagnesium bromide dehydration, bromination, and double dehydrohalogenation would yield the desired product.

Of course, you'd need to make the isobutyl bromide and benzaldehyde first, but it avoids the sonogashira.

There is a reagent called trimethylsilyl acetylene, which has one end of a normal acetylene molecule protected from reaction. brominate the benzene, sonogashira with TMS-acetylene to TMS-ethynylbenzene, remove the TMS group (K2CO3 in methanol I believe), sonogashira #2 with iPrBr

Ah that sorta makes sense. Do you know if it matters if I use H2SO4 as the solvent instead of water, so I get H2S2O7 rather than dilute H2SO4? I've still got a litre of so of 98% which mum bought home from work for me

 

And yeah, I'll be careful mum gets really pissed off when i fumigate the house with anhydrous acid gases (she wasnt happy when i filled the house with HCl). I'll do it outside. While my parents are at work.

xD

 

I should probably order some nitrate now

You can't use conc. H2SO4 for absorbing the SO3, because it will suck up the NO and NO2 to form nitrosylsulfuric acid: http://en.wikipedia.org/wiki/Nitrosylsulfuric_acid. IIRC, H2SO4 also dissolves SO2 pretty well.

You see, a 1:1 mix of NO and NO2 dissolved in water is nitrous acid, so we can expect the following to occur readily:

[ce] NO + NO2 + 2H2SO4 -> 2NOHSO4 + H2O [/ce]

Problem with that is, i don't have a sealed lead chamber, and i don't have the equipment to make one. I've got an old lead acid battery i could take apart to get hte lead out of but no way of welding it. (I'm only 16 xD)

But perhaps I could combine the contact process and lead chamber process?

I'm thinking, instead of V2O5 catalyst, run the SO2 through XNO3 to oxidise it, a bit like you recommended. It'd get used up but I guess thats something i could live with.

What gets left over when XNO3 oxidises something? Do you get XNO2 + O, XO+N2+O or something else?

Once I've got the SO3, the rest is easy. I can bubble it through concentrated sulphuric acid to get oleum.

You can run it in a big plastic container; see here: http://www.sciencemadness.org/talk/viewthread.php?tid=2824

[ce] NO2 + SO2 -> NO + SO3 [/ce]

[ce] 2NO + O2 -> 2NO2 [/ce]

SO3 is pretty horrible stuff, as are nitrogen oxides, and not to be taken lightly.

no, no and no.

Ferric sulfate can indeed eject SO3 at high temperatures, but this requires fused quartz apparatus and at those temperatures, SO3 substantially decomposes to SO2 and O2. The most workable method for SO3 is decomposition of sodium bisulfate, as seen on sciencemadness.org.

SO2 will not substantially oxidize in water, and bubbling O2 through it will fill the room with SO2 instead.

electrochemical series is largely useless here. V2O5 is a pretty strong oxidizer and is used for a reason. It's very sensitive to preparation methods (overheating makes it useless) and works best in a molten flux of cesium and potassium sulfates on a porous catalyst support, IIRC.

You might want to try the "lead chamber" process, which involves burning sulfur mixed with KNO3 in a sealed container, within a larger container with some water in the bottom. The small amounts of NOx formed catalyze the oxidation of SO2 to SO3 by O2. SO3 dissolves in the water to produce dilute sulfuric acid.

what's the lowest temperature smelting I can do and can it be done with a bunsen?

smelting what? You need to get the temperature above the melting point of the metal. I believe that PbO with finely powdered charcoal would be workable.

You're biggest problem is that a volume of ethanol added to a volume of water does not make a volume equal to the other two volumes you just added, and the amount of volume contraction has a lot to do with the proportions.

If you use the volume of the input stream and the specific gravity (density), you can calculate the mass of the input stream.

Volume x mass/Volume = mass.

Then, apply the wt% you measure to figure out what the total mass of ethanol present. Using the specific gravity and volume of the waste stream, figure out how much ethanol is not being recovered. Then, you need the density of anhydrous ethanol and you have your number.

The difference between the boiling point of methane and chloroform. Methan's boiling point is -164 C and chloroform's boiling point is 62 C. Explain the difference between two boiling points.

 

I do not get this question at all and really need help answering this particular question. Both the CHCL3 and CH4 have the same shape....but how does that affect their boiling points.

There are two factors that govern boiling points. The first is the kind of bonds that the molecules can participate in and the second is molecular mass.

Different kinds of intermolecular bonds can be formed, and if the liquid wants to boil, these bonds need to be broken, which requires energy. The stronger the intermolecular bonds, the higher the boiling point. Mass is also important, since on a molecular level, temperature is a measure of the kinetic energy of the molecules, and kinetic energy is dependent on mass. Think about it this way: It takes a lot more effort to keep an elephant airborne than it does to keep a balloon floating.

Or something like that. I never was very good at anything physicsy.

Big hint: start with a wittig reaction to make styrene. SN2 will be important later on. Think cyanide.

so you guys are saying that its tottaly impossible to get MgO back to Mg there is no way to ever remove the O?

Oh it's real simple. Just heat the MgO with molten sodium, potassium, or lithium under argon.

Am I the only one who finds it hilarious that you're all responding to a 2 year old post?

confused apparently felt it necessary to necro the thread for a one-liner with no content.

Anyway, it should be possible to use a solid cast or machined paraffin block with some additives as a fuel source, using a separate chamber of liquid or gaseous oxidizer. Nitrous oxide could certainly work and perhaps the canisters sold for whipped cream could be utilized in some way. The rate at which the oxidizer is released into the combustion chamber would be critical, making this a far more advanced project (and much more interesting in my opinion) than a rocket using KNO3 and sugar.

Tin will react with HCl without heating, but the reaction is slower. If you use concentrated HCl, it will go faster no matter what temprature. Moderate warming should help it along nicely without sending acid spatter and fumes everywhere. I'd use excess tin (so lots, and when it stops bubbling, just use the liquid as is). If you store it in an airtight container with a little extra HCl added, it should last a very long time. Making crystals is tricky and not worth the effort if you just need a solution to test with. If I needed crystals, I'd buy them to save myself the trouble.

Look up the mechanism for thionyl chloride acting on carboxylic acids. Oxalyl chloride behaves exactly the same way, except you need to put one more arrow in. It's a little tricky and not necessarily intuitive, so looking it up is probably the best way to go.

Let's take an odd example, but one where the chemistry is relatively simple.

Potassium has a naturally ocurring isotope of mass 40 which decays (mainly- but lets ignore the other possibility for a minute) by beta decay to give argon. It has a half life of 1.25 billion years I think)

 

Imagine that we extract some of this isotope of potassium and turn it into the chloride.

 

It decays slowly but surely to argon, and of course, argon doesn't form a chloride.

 

So the reaction is

2 KCl --> 2Ar +Cl2.

The potassium was there as K+ ions and when they lost a beta particle they (briefly) became Ar++ ions.

Now Ar(II) is a much stronger oxidant that you get in any normal sort of chemistry. It's perfectly capable of oxidising chloride to chlorine.

 

In case you are wondering, the beta particle will hit something and stop. Then it's just an electron. Now tha electron (on it's own) is a very powerful reducing agent. It can certainly reduce Ar+ to Ar

Actually, beta decay would convert potassium into calcium...

[ce] KCl -> CaCl^+ + e^- [/ce]

That's an interesting concept.

Electrolysis of a solution of ammonium chloride in water giving a sodium compound.

Here's a relatively recent reference to a related compound, just to spice things up a bit.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THS-44VFYDR-15&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1a40443903d2e0c998a7cf6732838681

The older reference used sodium amalgam and concentrated NH4Cl solution. I see no electrolysis. Take note that this reference is for quaternary ammoniums and uses electrolysis. Perhaps the result of the older procedure contained a small fraction of the ammonium compound, but would have been far from pure.

I'm not quite sure, but similarly, I agree with captain panic, in that while glycerol may increase the viscosity, but a cross- linked polymer is required. Furthermore, I was recently interested in glycerol's (or glycerine's, as its more commonly known) uses, and I believe I read something regarding that if it is not combusted in a particular fashion, it will give off acrid fumes, which I assume are generally an unwanted by- product, however of glycerine's combustion, I really know little concrete knowledge of. Some justification or reconciliation by others is required, I suppose. Any help?`

You do have a point. Glycerol undergoes dehydration to generate acrolein, which is quite toxic and oxidizes to acrylic acid, which is also toxic. I suspect that as a gel, it would not be a clean burn at all. Probably rather sooty, since it isn't being force-fed oxygen to complete the combustion. If you were to solvate it in methanol and spray the mix into a burner system, sure, you could get it to burn completely without toxic fumes.

My method is to use Chemical Formula, all the best/Strong passwords are a combo of letters and numbers, And it`s easy to code the passy so you don`t forget, IE/

 

C12H22O11 you can write down "Sugar" as a reminder.

 

but it gets Really cool where the password text is Case Sensitive, you can get really funky like;

 

Na2CO310H2O you can write down "Washing soda".

 

just a thought

I do the same, using names of my favorite chemicals. If the password allows, they often have hyphens and commas as well. Some of mine are in the 30s as far as numbers of characters.

Examples (not my actual passwords):

diethyleneglycoldibutylether

1,2,4-trichlorobenzene

coppersulfatepentahydrate

dinitrogenpentoxide

6-bromoindole

thanks very much for your help.

i didn't know anything about that acid.

 

and don't you worry, i'm just a high school student, preparing for the iit jee 2009; i won't think of dealing with such dangerous stuff.

by the way, do there exist stuffs like 'super bases'?

 

could you name a few?

 

and could you please let me know about some more unconventional reagents, or links to places where i could get something?

 

that would be a very great help.

superbases? try wikipedia

by definition, they are all water reactive.

That would be an electrophilic aromatic substitution, as described here: http://www.cem.msu.edu/~reusch/VirtualText/benzrx1.htm

The HSbF6 is fluoroantimonic acid, the strongest superacid known. It is powerful enough to protonate simple alkanes, so phenol and bromine should be pretty easy.

[ce] Ph-OH + HSbF6 -> [Ph-OH2]^+[sbF6]^- [/ce]

The phenylhydronium ion there would behave like a nitro group, explained in the reference I linked you above. Therefore, substitution would occur preferably on the 3 position. Since HSbF6 is such a strong acid, you can safely assume that virtually all of the phenol is protonated all the time.

The bromine is also probably protonated on on end of the dimer, which induces a dipole moment and drives the electrophilic aromatic substitution reaction.

As for safety (from wiki): HF-SbF5 is rapidly and explosively decomposed by water. It reacts with virtually all known solvents.

If you're even vaguely considering working with this stuff, don't.