Sciencemadness Discussion Board

The short questions thread (1)

 Pages:  1    3    5  ..  7

kclo4 - 2-11-2008 at 22:23

Quote:
Originally posted by Picric-A
Has anyone made this before?
All the synthesis look difficult so i was wondering if anyone has found a way that is suitable to perform in a home lab.
This method looks feasable:
Raschig synthesis: Aqueous ammonium nitrite is reduced by HSO4−/SO2 at 0°C to yield a hydroxylamido-N,N-disulfate anion, which can be hydrolyzed to give (NH3OH)2SO4.

NH4NO2 + 2SO2 + NH3 + H2O → [NH4]2[N(OH)(OSO2)2]
[NH4]+2[N(OH)(OSO2)2]2− + H2O → [NH4][NH(OH)(OSO2)] + [NH4][HSO4]
2[NH4]+[NH(OH)(OSO2)]− + 2H2O → [NH3(OH)]2[SO4] + [NH4]2[SO4]
Solid NH2OH can be collected by treatment with liquid ammonia. Ammonium sulfate is insoluble in liquid ammonia and is removed by filtration; the liquid ammonia is evaporated to give the desired product

But the liquid ammonia would be a problem along with having to use Ammonium Nitrite which is dangerously explosive.


Not to sure how it works, but it sounds like a good method.

" 40g potassium nitrite (KNO2) and 50g potassium acetate (CH3COOK) are dissolved in 100ml ice water. 750g finely crushed ice is added. Into this solution a stream of sulfur dioxide (SO2) is bubbled until the solution smells of SO2. The temperature must be kept below 0°C through the whole reaction. The salt of K2[HON(SO3)2] separates and is filtered off and washed with ice water. The salt is dissolved in 500ml 0.5 M HCl and boiled for two hours. Still boiling a solution of Barium chloride (BaCl2) is added as long as barium sulfate (BaSO4) precipitates (maybe CaCl2 will do instead). The BaSO4 is filtered off and the clear filtrate is evaporated to dryness. The residue consists of Potassium Chloride (KCl) and NH2OH*HCl. Anhydrous ethanol(EtOH) is used for extraction of the Hydroxylammonium chloride, the KCl remains undissolved. The EtOH is evaporated on a water bath and the product can be recrystallised from water (mp 151°C).

A similar method can be found in Organic Synthesis.(http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0318)

Ref: Jander-Blasius, Lehrbuch der anal. u. prep. anorg. Chemie "
That is from the rhodium archive, here is a link to one of the many mirrors of it. http://www.m-pab.ru/docs/rhodium/hydroxylaminehcl.html

Maja - 3-11-2008 at 03:45

I have searched methods for preparing allyl alcohol and found one which uses anhydrous oxalic and glycerol.. So my question is : Can I use hydrated oxalic acid ?

Oh, by the way ... Maybe someone can post allyl alcohol synthesis excluding Oxalic/Glyrecol route ? :)

Thank you.

solo - 3-11-2008 at 04:21

this may help.....solo

Allyl alcohol, 2-propen-1-ol is an organic compound with the formula CH2=CHCH2OH. It is a water soluble, colourless liquid with an ethanol like odour at low concentrations and a mustard-like pungent odour at higher concentration. Allyl alcohol is used as a pesticide and as a raw material for the production of many chemical compounds.

Allyl alcohol can be obtained by many methods: hydrolysis of allyl chloride, by oxidation of propylene oxide with potassium alum at high temperature, dehydrogenation of propanol, and by the reaction of glycerol and formic acid. Allyl alcohol is the smallest representative of the allylic alcohols. Allyl alcohols in general can be prepared by allylic oxidation of allyl compounds by for instance selenium dioxide.

.......source,

http://en.wikipedia.org/wiki/Allyl_alcohol

http://www.organic-chemistry.org/synthesis/C1O/alcohols/ally...
http://www.freepatentsonline.com/3692849.html

Synthesis of oximes, aziridines, and allyl alcohols derived from substituted 1-phenyl-1-nonen-3-ones as potential cytotoxic and antitumor agents.
1: J Pharm Sci. 1978 Nov;67(11):1536-9.

[Edited on 3-11-2008 by solo]

solo - 3-11-2008 at 11:50

I don't understand this term....in reference to heating a solution......solo

"heated in a metal-bath"

or better the whole phrase,

"The light yellow solution was heated in a metal-bath at 120' to remove water, first at atmospheric pressure and finally at 130-140' (15
mm.)"



[Edited on 3-11-2008 by solo]

Klute - 3-11-2008 at 13:40

Maybe some kind of low melting alloy? I think such mixtures used to used a long time ago.. is this aold procedure?
You could just aswell use high boiling mineral oil I guess, or even a mantle...

[Edited on 3-11-2008 by Klute]

S.C. Wack - 3-11-2008 at 15:14

For instance
http://en.wikipedia.org/wiki/Wood%27s_metal

[Edited on 3-11-2008 by S.C. Wack]

Sauron - 4-11-2008 at 02:30

Would someone plase remind me of the url for the site that provides worldwide patents fulltext for free?

I am after a DDR (E.German) Patent 26660 (1960) to Heintz (I think the name is really Heinz, Dieter Heinz) and Thilo concerning preparation of diphosphorus trioxide.

[Edited on 5-11-2008 by Sauron]

Klute - 4-11-2008 at 06:07

espacenet.com?

Thilo has only one patent in 1960 on dichlorophosphoric esters... I didn't see anything on phosphorus oxide (III)...

http://v3.espacenet.com/publicationDetails/originalDocument?...

Research results:
http://v3.espacenet.com/searchResults?locale=fr_FR&IN=Th...



No results for Neintz in 1960...

[Edited on 4-11-2008 by Klute]

Formatik - 4-11-2008 at 12:33

There are no German patents that can be found for these two authors at DEPATISnet or espacenet. But Heinz and Thilo do have 1966 British patent: GB1027679. Which is likely the English variant of the same patent.

Sauron - 4-11-2008 at 14:25

Thanks. Heinz also authored the review I posted (in German) comparing his process with those of Thorpe (1890) and the 1945 German process using PCl3 and tetramethylammonium sulfite in liquid SO2.

As I can't easily get elemental P of any sort but can get (in fact have) PBr3 it is obvious that the latter method would be my only option if I wanted to make P2O3.

My only motivation for doing so would be to test my hypothesis that the work of Roger Adams on making inorganic acid chlorides from certain oxides (in JACS) can be extended to P2O3 -> PCl3. The reagent is oxalyl chloride.

So the combination of an onerous to make, toxic precursor and an expensive reagent and liquid SO2 solvent really render this a rather academic exercise, although possibly a publishable one.

[Edited on 5-11-2008 by Sauron]

starman - 5-11-2008 at 02:20

Quote:
Originally posted by Maja
I have searched methods for preparing allyl alcohol and found one which uses anhydrous oxalic and glycerol.. So my question is : Can I use hydrated oxalic acid ?

Oh, by the way ... Maybe someone can post allyl alcohol synthesis excluding Oxalic/Glyrecol route ? :)

Thank you.

Hey Maja - Have done this one for formic acid with allyl alcohol as considerable side product.Water of crystallation is actually required or you need to add H2O.The monohydrate is said to be optimal for HCOOH concentration,dont know if the anhydrous would be ideal to maximise the alcohol.

[Edited on 5-11-2008 by starman]

[Edited on 5-11-2008 by starman]

Maja - 7-11-2008 at 16:22

Thank you solo and starman!

One more question : Can phenylanthranilic acid be hydrolysed to anthranilic acid ? If yes, what conditions ? :)

Nicodem - 10-11-2008 at 01:24

Quote:
Originally posted by Maja
One more question : Can phenylanthranilic acid be hydrolysed to anthranilic acid ? If yes, what conditions ? :)

None of the many possible isomers - for which an incomplete name such as "phenylanthranilic acid" would fit - can be hydrolysed simply because there is no hydrolysable bond (the possible isomers are N-, 3-, 4-, 5-, and 6-phenylantranilic acids). Only phenyl antranilate would be hydrolysable, but that is a different compound from any of the phenylanthranilic acids.

kazaa81 - 10-11-2008 at 10:45

Is it possible to reduce trichloroethylene in order to produce acetylene ?

solo - 10-11-2008 at 11:26

Quote:
Originally posted by kazaa81
Is it possible to reduce trichloroethylene in order to produce acetylene ?


--------------------------------------------------------------------------------


Reductive Dechlorination of DNAPL Trichloroethylene by Zero-Valent Iron
Robert Orth, Taiwo Dauda, David E. McKenzie,
Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management, Vol. 2, No. 3, July 1998, pp. 123-128,


Abstract:
The reduction of trichloroethylene (TCE) by metallic iron was studied under conditions in which the trichloroethylene would exist as a separate phase in a water/iron system. The products of the reaction were determined over time using gas chromatography (GC) and mass spectrometry (MS). The kinetics of the loss of TCE and the formation of chloride were determined to follow zero-order kinetics under these conditions with zero-order rate constants of 4.8 × 10–³ mg TCE hr–¹ g–¹ iron and 3.8 × 10–³ mg Cl hr–¹ g–¹ iron. The zero-order rate constant was observed to depend on the mass or iron present. The reaction was carried out in deuterium oxide to compare the reaction pathways suggested in the literature for solution reduction of TCE. It was observed that the major product was acetylene with minor components of ethane and ethene. The deuterium oxide showed that the ethene and ethane were composed of a 68% total deuterated ethene and 32% ethene containing only one hydrogen. No deuterium was evident when acetylene formed in the deuterium oxide system, indicating that all of the hydrogen in the dense nonaqueous phase liquid (DNAPL) arises from TCE. The result of this study indicates that metallic iron can dechlorinate DNAPL TCE.

Attachment: Reductive Dechlorination of DNAPL Trichloroethylene by Zero-Valent Iron.pdf (657kB)
This file has been downloaded 767 times

497 - 10-11-2008 at 20:29

Here's a question or two:

What exactly happens when SO2Cl2 reacts with water? I have read that with excess SO2Cl2 it forms chlorosulfuric acid, could this be a useful route in preparing ClSO2OH? Also what kind of equilibrium is there between water and ClSO2OH? Like ClSO2OH + H2O <-> H2SO4 + HCl. More importantly, could this possibly be useful in preparing H2SO4 of decent concentration? It seems like it would work since AFAIK HCl is not very reactive at all toward conc. H2SO4, only toward SO3. Or alternatively could one use a catalyst to make 2ClSO2OH --> SO2Cl2 + H2SO4 and prepare anhydrous H2SO4 while distilling off the SO2Cl2? I have seen that reaction mentioned but never any details.

I think this could be useful since SO2Cl2 looks fairly easy/cheap to synthesize. And I would really like to have some chlorosulfonic acid because it works so nice to make tosyl chloride. Also might be useful if conventional sources of H2SO4 disappear.

[Edited on 10-11-2008 by 497]

Formatik - 10-11-2008 at 23:32

The old Gmelin mentions that sulfuryl chloride decomposes in water under a strong liberation of heat, forming H2SO4 and HCl acid. A little bit of water does form chlorosulfuric acid and hydrochloric acid. The newer Gmelin might give a lot more information about its hydrolysis. It dedicated like two-thirds of a page to POCl3 hydrolysis. There are some references stating that SO2.OH.Cl reacts explosively with water (Chemie: Grundwissen für Ingenieure by G. Blumenthal, et al. (2006), p. 296). That would be a tricky way to pursue H2SO4.

In the case of regular H2SO4, why not instead bubble Cl2 into an SO2 solution oxidizing it, then just boil the water and HCl off (it could work to bubble both gases simultaneously into H2O, and one could probably even bubble these gases up until the H2SO4 gets concentrated, which in the end might need some boiling to get rid of the rest HCl), that way there is also no need to go through effort of preparing SO2Cl2 and work around the violent reaction of it with water.

Ann.

smuv - 11-11-2008 at 09:19

What journal does Ann. stand for? Annales De Chimie?

solo - 11-11-2008 at 14:48

.........see journal abbrev.'s.......solo

http://www.geocities.com/baskargreen/journalabbr.htm

smuv - 11-11-2008 at 15:06

I had previously checked that page and it doesn't just have ann. it has ann. XYZ.

thank you though.

Ann.

Formatik - 11-11-2008 at 15:21

It's Annalen der Chemie, a.k.a. Justus Liebig's Annalen der Chemie, or just Annalen.

http://en.wikipedia.org/wiki/Annalen_der_Chemie

smuv - 11-11-2008 at 15:25

Thank you!

497 - 11-11-2008 at 18:07

Quote:

In the case of regular H2SO4, why not instead bubble Cl2 into an SO2 solution oxidizing it, then just boil the water and HCl off (it could work to bubble both gases simultaneously into H2O, and one could probably even bubble these gases up until the H2SO4 gets concentrated, which in the end might need some boiling to get rid of the rest HCl), that way there is also no need to go through effort of preparing SO2Cl2 and work around the violent reaction of it with water.


I agree, that would be easier. I too have seen it mentioned that SO2Cl2 reacted "explosively" with water, but I don't think that means it wouldn't be possible to use that route. I have also seen it said that SO2Cl2 forms a hydrate in cold water, so that leads me to believe the reaction wouldn't be too hard to handle. You could even recycle the HCl back to make more Cl2 ;)

I'm also after ClSO3H, this seems to be a very useful compound.
Since

ClSO3H <--> SO2Cl2 + H2SO4

is known to work, maybe one could synthesize it by simply absorbing SO2 and Cl2 into H2SO4, since SO2Cl2 could be formed in situ? Would that work?

Here is a good book on all the uses of chlorosulfonic acid, too bad google books only lets you see a third of it. If anyone has a complete copy I would love have it...

[Edited on 11-11-2008 by 497]

woelen - 12-11-2008 at 11:05

SO2Cl2 does not react explosively with water. Actually, it reacts very slowly. I have this chemical and when I add this to water, it forms a blob at the bottom, which slowly dissolves (takes tens of minutes with plain water at room temperature).

497 - 12-11-2008 at 18:43

Thank you for that information. I guess that's why they say it can react explosively. Maybe at high temperature and large amounts?

According to Kirk-Othmer the reaction of stoiciometric amounts of SO2Cl2 with H2SO4 produces ClSO3H and is reversible with a mercury catalyst. No other details given..

Picric-A - 16-11-2008 at 07:43

I know you can use Sodium chlorite to oxidise alcohols but has anyone every used Sodium Chlorate?
Is it even possible? Sodium chlorate is a strong oxidising agent so i would think it would be possible...

UnintentionalChaos - 20-11-2008 at 23:10

I need to construct a terminal E-bromoalkene at the end of a medium length hydrocarbon chain (with a cyclic acetal at the far end). I can put a halide, amine, or alcohol on the terminal position of the original hydrocarbon chain pretty easily, so any could be starting points. I could even use a different starting compound if a decarboxylation is necessary somewhere.

Nicodem - 21-11-2008 at 00:19

Quote:
Originally posted by UnintentionalChaos
I need to construct a terminal E-bromoalkene at the end of a medium length hydrocarbon chain (with a cyclic acetal at the far end). I can put a halide, amine, or alcohol on the terminal position of the original hydrocarbon chain pretty easily, so any could be starting points. I could even use a different starting compound if a decarboxylation is necessary somewhere.

You did not explain if you want to make the end compound by homologating the starting one, like this:
R-CH2CH2-Y => R-CH2CH=CHBr
or by modifying the end group like this:
R-CH2CH2-Y => R-CH=CHBr

If the first is an possibility then you can take your OH terminated starting compound, do a Swern oxidation to the aldehyde and then a Wittig reaction with CH2Br2 derived Wittig reagent. The problem is that using this specific reagent some references claim the (Z)-product as the major while other claim the (E)-product as the major one. It might be substrate dependend, but Wittig reactions in general tend to give more of the Z diastereoisomer anyway.
Else, you can do a Takai olefination on the aldehyde instead of the Wittig. The reaction works fine even on fragile substrates, so I your acetal protection on the other side should withstand without problems (just check on what complex substrate it can be used successfully: Organic Letters, 8 (2006) 6039-6042). It also has a very great E selectivity as opposed to the Wittig which tends to give more of the (Z)-product.

497 - 21-11-2008 at 03:19

Two questions:

Does anyone know a good way of separating 4-methoxyphenol and 1,4-dimethoxybenzene? Or even an easy way to tell them apart? Hopefully other than (vacuum?) fractional distillation?

Does anyone have experience with using trimethylglycine to methylate phenols? I'm really wondering if it will methylate something like hydroquinone fully to 1,4 dimethoxybenzene or stop at 4-methoxyphenol? I haven't found any information other than the one page from the Hive.

[Edited on 21-11-2008 by 497]

Klute - 21-11-2008 at 04:54

Well, a basic wash will remove all the phenol. Also, IIRC, dimethoxybenzene is pretty volatil with steam while p-MeO-Phenol isn't.


Trimethylglycine doesn't seem very appealling. I would rather go with trimethylphosphate or ethylsulfonate/tosyl methyl esters.

UnintentionalChaos - 21-11-2008 at 09:51

Quote:
Originally posted by Nicodem
You did not explain if you want to make the end compound by homologating the starting one, like this:
R-CH2CH2-Y => R-CH2CH=CHBr
or by modifying the end group like this:
R-CH2CH2-Y => R-CH=CHBr

If the first is an possibility then you can take your OH terminated starting compound, do a Swern oxidation to the aldehyde and then a Wittig reaction with CH2Br2 derived Wittig reagent. The problem is that using this specific reagent some references claim the (Z)-product as the major while other claim the (E)-product as the major one. It might be substrate dependend, but Wittig reactions in general tend to give more of the Z diastereoisomer anyway.
Else, you can do a Takai olefination on the aldehyde instead of the Wittig. The reaction works fine even on fragile substrates, so I your acetal protection on the other side should withstand without problems (just check on what complex substrate it can be used successfully: Organic Letters, 8 (2006) 6039-6042). It also has a very great E selectivity as opposed to the Wittig which tends to give more of the (Z)-product.


I was hoping to avoid the schlosser modified wittig reaction in favor of a vinyl hailde- alkyl halide coupling using a lithium diorganocopper (Gilman reagent) for making the final product. I need to couple with cheap-as-dirt isopropyl bromide for the diorganocopper, whereas the schlosser modified wittig is very reagent heavy and I'd need isobutyraldehyde to get the double bond in the right spot.

The fact that that reaction lengthens the chain is even better since I can start with poly-caprolactone plastic and not have to extend the chain after hydrolysis (or make cycloheptanone and do a baeyer villager oxidation)

Do you think a nitrile would withstand attack by the lithium diorganocopper, because that would be an easier and even more convenient protecting group than an acetal followed by mild oxidation at the end (silver (I) or hypoiodite). It needs to be a carboxylate at the end of the day anyway

[Edited on 11-21-08 by UnintentionalChaos]

497 - 21-11-2008 at 11:24

Quote:

Trimethylglycine doesn't seem very appealling. I would rather go with trimethylphosphate or ethylsulfonate/tosyl methyl esters.


Yes I agree, but I was hoping it would be usable because I can get it pure for $30 per kilogram OTC. I haven't seen any alternative that can be bought nearly that easily and cheaply, much more effort involved with preparing them..

Also it occurred to me that it might work better to methylate 4-MeOphenol directly instead of HQ, since it can be easily prepared via the H2SO4/MeOH/HQ/BQ route.

Edit:
Another question:
I'm confused about the paper found here, does it ever actually tell how much of the various dihydroxybenzenes are put through the catalyst tube? Am I missing something? It gives all kinds of other information, but no hint of an actual quantity, at least that I can see.

It does look like an interesting alternative to conventional methylating agents. 400*C with a Cs2O catalyst isn't too bad either.

[Edited on 22-11-2008 by 497]

Klute - 22-11-2008 at 07:03

Well, it could be worth a try, I must admit I was pretty sceptical with TMP at first, especially the solventless >150°C method, and it worked great afterall.

How would you react the two solids? As a solution/suspension in DMF or similar?

For the article, I'm under the impression that the amount of solution introduced is based on how much the 18mL/H of N2 can vaporize. Not really a preparaitive procedure it seems.


Why not try the MeBr method Painkilla developped? It worked great for HQ to DMB, and you can recycled the bromide, whitout been exposed to any amount of the methylating agent if you plan things ahead?

It could nice to see how Betaine goes, but I wouldn't recommend buying a kilo immediately.

497 - 22-11-2008 at 13:49

Quote:

How would you react the two solids? As a solution/suspension in DMF or similar?


As far as I can tell they are melted and reacted directly. I think the HQ melts and dissolves (some of?) the betaine, since betaine by itself melts with decomp at ~305*C.

And thanks for telling me about the MeBr methylation, I hadn't seen that thread. I have often wondered whether it could be used, but never saw an actual procedure until now.

Edit:
Yet another (maybe not so) quick question; is there a way to add -CH2-CHO to a phenol or methoxybenzene? Or is it possible to "formylate" a methyl group?

The reason I ask is, if there was a half way simple way to 2,5-diMeO-phenylacetaldehyde it would be a piece of cake to get to the amine via hydroxylamine to form the aldoxime and then Mg/NH4COOH/MeOH reduction...

It seems like there are a lot of possible routes, but I wonder if there are there any practical ones?

Theoretically you could go HQ -> HQdiacetate -> 2,5-diOH-acetophenone -> 2,5-diMeO-acetophenone -> 2,5-diMeO-phenylethanol -> 2,5-diMeO-phenylacetaldehyde... But that's way too many step to be practical, not to mention needing Ac2O..

Hmm... maybe like this? 2,5-diMeO-benzaldehyde -> 2,5-diMeO-mandelic acid -> 2,5-diMeO-acetylmandelic acid -> 2,5-diMeO-phenylacetaldehyde... Not sure about the last step, but all the others seem to be quite high yielding according to this.

Or maybe.... 1,4-diMeO-benzene -> 2,5-diMeO-acetophenone via the Hosch reaction with acetonitrile...

Anyway it seems like an interesting possibility.. I really wouldn't mind avoiding the Pd/C, NaBH4, etc. involved with the alternatives.

PS. Another interesting reaction I just found: Acetonitrile reacts with benzyl alcohols with an HCl catalyst to form N substituted acetamides that can then be easily acid hydrolyzed to amines. Not sure about yields though..

Acetonitrile with the benzyl chloride is another way, supposedly high yielding.

[Edited on 23-11-2008 by 497]

[Edited on 23-11-2008 by 497]

Klute - 23-11-2008 at 05:15

Well, you can halomethylate withe acetaldehyde and HX IIRC, then do a gabriel or go to the aldehyde (watch out phenylacetaldehdyes polymerise extremly easily).

Your route via acetophenone will not work as you will obtain the 1-phenylethanol which cant be oxidized to pheneylacetaldehyde, just back toacetophenone. You would need the primary alcohol b-phenethylalcohol.

You could alkylate diethylmalonate with a benzyl halide, hydrolyze and decarboxylate to the propanoic acid, form the amide and do a hoffman degradation to the amide. I think there is a J Med Chem paper going on these lines.


The maandelic route doesn't seem very appealing to me, requiring cyanide and acetyl chloride, and having unknown yields.

The hösch reaction requires a very activated arene, and dimethoxybenzene is not activated enough. Maybe p-methoxyphenol could work there, but then again there isn't any direct way from acetophenone that I recall off right now...

Unfortunaly, the benzyl alcohol and acetonitrile from a N-acetyl benzylamine. Your amine will be 1 carbon too short that your targeted compounds..

[Edited on 23-11-2008 by Klute]

497 - 23-11-2008 at 05:36

Quote:

Well, you can halomethylate withe acetaldehyde and HX IIRC


Great idea! I hadn't thought of that one. Just what I was looking for. Just quickly searching around, I haven't found much information on it though. I'll have to look more.
Edit: Hah, I was searching "halomethylation" which obviously isn't going to happen with acetaldehyde :P. It is 4:50 am here after all, I have an excuse at least..
Quote:

Your route via acetophenone will not work as you will obtain the 1-phenylethanol which cant be oxidized to pheneylacetaldehyde, just back toacetophenone. You would need the primary alcohol b-phenethylalcohol.


Oh well, I wouldn't really like that route even if it would work.
Quote:

The maandelic route doesn't seem very appealing to me, requiring cyanide and acetyl chloride, and having unknown yields.


I agree...
Quote:

Unfortunaly, the benzyl alcohol and acetonitrile from a N-acetyl benzylamine. Your amine will be 1 carbon too short that your targeted compounds..


;) That's why I was hoping to use a phenylethanol (or chloride). I guess getting the extra carbon on that side chain is really the biggest problem..

[Edited on 23-11-2008 by 497]

[Edited on 23-11-2008 by 497]

stoichiometric_steve - 23-11-2008 at 07:31

497, all you want is 2C-H?

497 - 23-11-2008 at 12:54

Quote:

497, all you want is 2C-H?


Why do you ask? I wouldn't want to do anything illegal! ;)

But if I were , which I'm not, it seems like it would be awfully easy to go like so: HQ -> 4-MeO-phenol -> 1,4-diMeO-benzene -> 2,5-diMeO-phenylethyl chloride(bromide) -> 2,5-diMeO-phenethylamine...
I'm a little unsure of how well the haloethylation works. There seems to be quite a few patents and such that say it will, but I don't know how well, especially with those methoxys on there. If the methoxys were a problem you could probably haloethylate HQ and methylate later... I think all the other reactions are pretty much standard and well known, as long as the Delépine Reaction will in fact work on a -CH2-CH2-X.

As smuv says below, the Willgerodt-Kindler rearrangement could theoretically work, with sulfur, NH3, and pyridine it is said to get a pretty good yield of 2-phenylacetamide from acetophenone, but what about a substituted acetophenone? And what does it take to reduce the acetamide to amine?


[Edited on 23-11-2008 by 497]

smuv - 23-11-2008 at 13:03

@ 497

Not that its very elegant, but phenylacetamides can be made from acetophenones through the Willgerodt-Kindler. The phenylacetamides can of course be reduced to amines.

Additionally if you produce the propiophenone via the hoesch, nencki, or friedel-crafts you can produce the phenyl propionamide which theoretically could yield the phenylethylamine after a hofmann rearangement.

Maybe not practical or elegant, but...hey it gets you there from xPhenones.

Klute - 23-11-2008 at 17:09

LiAlH4 or diborane reductions (NaBH4/BF3.Et2O, NaBH4/I2, etc) will reduce acetamides to amines.

Why is it you would like to avoid the traditional nitroalkene-nitroalkane-amine? Most of the reagents you mentionned above are much harder to aquire than NaBH4 and Pd/C or even zinc dust.. If it's to explore new routes and compare results, god be with you :)

Edit: IIRC the wildergot requires a pressure vessel, no? And forms H2S.. uck..

[Edited on 24-11-2008 by Klute]

smuv - 23-11-2008 at 17:47

Quote:
Edit: IIRC the Willgerodt requires a pressure vessel, no? And forms H2S.. uck..


There are variations of the reaction that don't require a pressure vessel, but I believe they are lower yielding. The wildgerodt does indeed produce H2S (older variations also required H2S to help dissolve the sulfur).

Hey I never said it was good:P...I was just saying it could be done, and if someone did it I would tip my hat to them (so long as the product was legal;)) because the Willgerodt coupled with the Hofmann degradation is the most brutish method of making a phenylethylamine yet (IMO) from a mechanistic standpoint uses two very beautiful reactions.


[Edited on 11-23-2008 by smuv]

497 - 23-11-2008 at 18:50

Quote:

LiAlH4 or diborane reductions (NaBH4/BF3.Et2O, NaBH4/I2, etc) will reduce acetamides to amines.


Shit... that's exactly what I'm trying to avoid...

Quote:

Why is it you would like to avoid the traditional nitroalkene-nitroalkane-amine? Most of the reagents you mentionned above are much harder to aquire than NaBH4 and Pd/C or even zinc dust.. If it's to explore new routes and compare results, god be with you :)


Well, I guess I have some glimmer of hope that there is an easier way hiding out there somewhere... Maybe that's being a little too optimistic :(. Also I want to avoid NaBH4/LiAlH4 if at all possible.

Now that I think about it, part of the reason is simply that I really enjoy trying to solve problems and/or find better ways to do things. And if something I come up with happens to help someone else down the line, all the better.
Quote:

because the Willgerodt coupled with the Hofmann degradation is the most brutish method of making a phenylethylamine yet (IMO) from a mechanistic standpoint uses two very beautiful reactions.


Hah, well said.

Still for some reason I really like the idea of making an aldoxime and then reducing it. Both of those reactions are pretty high yielding and require only very basic reagents and conditions. Like really basic, KNO2, HCl, NaHSO3, H2SO4, NaOH, methanol , toluene, NH4COOH and Mg... Just getting the damn 2-phenylacetaldehyde... that's what holds everything up.

I did see a patent where they do a one-pot synth of benzaldoximes directly from brenzal bromides with a >95% yield... But I can't think of any way of getting the bromide that would work with a MeO substituted benzene... it is easy to get the benzal bromide via H2O2/HBr/H2O/CHCl3 reacting with toluenes(or ethylbenzenes in my case), but it apparently only works with deactivated toluenes like p-nitrotoluene, so I guess that won't work..

Anyway... Going back to the traditional route, is there a good way to go from nitrostyrene to amine directly. I've seen were they did it with Zn, etc but I never saw a decent yield..

[Edited on 23-11-2008 by 497]

Maja - 26-11-2008 at 09:13

Maybe some ideas how to separate toluene and N-butanol ?

JohnWW - 26-11-2008 at 10:36

Quote:
Originally posted by Maja
Maybe some ideas how to separate toluene and N-butanol ?
Some sort of gas-liquid chromatography may be possible, on an appropriate medium in the packed column (a substance which strongly adsorbs one but not the other). Their boiling-points, 110.8 and 117ºC respectively, are too close for a simple distillation to be effective; and in any case, according to Perry chapter 13, n-butanol and toluene form a minimum-boiling-point azeotropic mixture with a boiling-point of 105.5ºC containing 37% n-butanol. So, noting that n-butanol is soluble in water to the extent of 9 parts in 100 parts of water at 15ºC while toluene is practically insoluble (only 0.05 parts in 100 parts of water at the same temperature), the most effective type of non-chemical separation would be by solvent extraction with water, which could be multi-stage to be fully effective.

Failing that, a chemical separation would be necessary, most likely involving a reaction that n-butanol (which is more reactive) undergoes as a primary alcohol (e.g. esterification with an acid, other than nitric acid or another acid that would nitrate or sulfonate the toluene, or formation of a butoxide by reaction with an alkali metal), but which toluene as an aromatic hydrocarbon does not undergo. The resulting esters would be soluble in several polar solvents in which toluene is insoluble, and they would also have much higher boiling-points than toluene. The alkali metal butoxides would be insoluble in toluene, but soluble, without reacting, in non-protonating polar solvents in which toluene would be much less soluble; or they could be hydrolysed, after evaporating or distilling off the toluene, back to n-butanol and an alkali metal hydroxide by adding water.

[Edited on 27-11-08 by JohnWW]

Maja - 26-11-2008 at 10:57

Thank you ! Extracting sounds good, but I would like to keep butanol it would be handy ! I will try simple esterification with acetic acid with a few drops of H2SO4... :)

Klute - 27-11-2008 at 16:34

497, well you can get benzyl bromide via bromomethylation, which requires very accesable reagents and apparently proceeds well (even very well in some case).

What is the procedure benzyl bromide --> benzaldoxime? Do you have a ref?

raiden - 27-11-2008 at 22:45

I have a quick question! How the hell do you work a vacuum pump? I've one that has been sitting around for months and would like to actually give it a whirl. Do you just connect it and turn it on or what? How do you release the vacuum? How do you stop it from going too far and crushing the g/ware?

Cheers.

solo - 27-11-2008 at 23:04

Just put an in line valve and turn it up as needed and shut it off when you want....solo

Nicodem - 28-11-2008 at 00:27

Quote:
Originally posted by raiden
I have a quick question! How the hell do you work a vacuum pump? I've one that has been sitting around for months and would like to actually give it a whirl. Do you just connect it and turn it on or what? How do you release the vacuum? How do you stop it from going too far and crushing the g/ware?

Cheers.

Essentially you use the on/off switch and that's it (after you check if there is enough oil, of course). Also, unless you want to ruin it with corroding chemical vapours you also need to attach a liquid nitrogen trap in the vacuum line. I do not understand your question about "crushing the g/ware". Just about any round bottom flask is supposed to be rated for 1 bar, so I do not know what kind of glassware you want to use which is not resistant to 1 bar pressure difference. Give more details about it.

raiden - 28-11-2008 at 04:55

Quote:
Originally posted by Nicodem
Essentially you use the on/off switch and that's it (after you check if there is enough oil, of course). Also, unless you want to ruin it with corroding chemical vapours you also need to attach a liquid nitrogen trap in the vacuum line. I do not understand your question about "crushing the g/ware". Just about any round bottom flask is supposed to be rated for 1 bar, so I do not know what kind of glassware you want to use which is not resistant to 1 bar pressure difference. Give more details about it.

How does one check the oil! I best find the model number and a manual I think!

Ahh, sorry, I just thought that most glassware would only be able to take a certain amount of vacuum and if you left the pump on it would implode them.

Thanks for clearing this up!

497 - 29-11-2008 at 12:17

Quote:

What is the procedure benzyl bromide --> benzaldoxime? Do you have a ref?


Well, I don't know about benzyl bromide --> benzaldoxime, the refs I found were for benzal bromide --> benzaldoxime, I think via in situ hydrolysis to benzaldehyde. I wish it was benzyl, that would make life a lot easier...

Here:
http://www.wipo.int/pctdb/en/wo.jsp?IA=US1989002377&DISP...

Maybe one could brominate a benzyl bromide under more mild conditions?

Or maybe there's a different way to directly add -CH2-CHBr2 without fucking with the methoxys?

EDIT:
Maybe all hope is not lost. Apparently aryl alcohols can be converted to oximes. Looks interesting, since hopefully you could get the substituted phenylethanols easily from hydrolysis of the haloethylation product.

Refs:
http://www.informaworld.com/smpp/content~content=a714009825~...

http://sciencelinks.jp/j-east/article/200201/000020020101A08...

Hmmm... There it may be possible to do an almost one-pot synth of benzaldoximes from benzyl halides. According to this benzyl halides can be hydrolyzed to alcohols at >95% yields, maybe one could take the crude organic layer and directly add CrO3/Al2O3 and then hydroxylamine HCl to get the oxime. Don't know about yields on the second part though. Have to get that ref.

Edit2:
I see, now that I have the ref, it just is a one-pot benzyl alcohol-->benzaldehyde-->benzaldoxime, nothing very special. Still, it gets surprisingly good yields..

If only you could easily get the 2-phenylethyl halide, everything else would be easy... Does anyone have some information pertaining to haloethylation? Halomethylation seems to proceed in high yield, but haloethylation seems to be a different story... Not that I've found much useful information on it. Maybe the aqueous/PTC type reaction that PainKilla posted could work with acetaldehyde?

[Edited on 29-11-2008 by 497]

[Edited on 29-11-2008 by 497]

smuv - 30-11-2008 at 21:35

Quote:
Well, I don't know about benzyl bromide --> benzaldoxime, the refs I found were for benzal bromide --> benzaldoxime, I think via in situ hydrolysis to benzaldehyde. I wish it was benzyl, that would make life a lot easier...


I don't understand are you trying to make phenylmethylamines? Maybe I am just missing something.
Quote:
Does anyone have some information pertaining to haloethylation?

Look for a ref posted by me, it is a review of halomethylation, that has a section about haloethylation/propylation. IIRC the products are 1-phenyl-1-halo-ethanes.

The quickest way to a phenylacetaldehyde that I can think of is via a fiedel-crafts with ethylene oxide followed by a careful oxidation of the alcohol. Watch out though, ethylene oxide is a toxic carcinogen. Don't worry about the methoxies, they can take a beating before cleavage.

Nicodem - 1-12-2008 at 01:06

497, from what I understand you are looking for ways to prepare benzyl amines and 1-phenylethylamines? At least that is what your not so comprehensible posts indicate but then again in some other posts it appears you want to prepare 2-phenylethylamines. Please pay more attention to what you are talking about as you tend to clutter this thread which is supposed to be for short questions only. If you want to continue like you do now I suggest you to open a thread in Beginnings or Organic section.

497 - 1-12-2008 at 01:08

Quote:

I don't understand are you trying to make phenylmethylamines? Maybe I am just missing something.


I'm operating under the assumption that having an extra carbon (e.g. starting with 2-phenylethyl bromide) will react similarly.. Am I wrong here?
Quote:

Look for a ref posted by me, it is a review of halomethylation, that has a section about haloethylation/propylation. IIRC the products are 1-phenyl-1-halo-ethanes.


Sad, you're right, just 1-phenyl-1-halos... too bad. It's funny, that ref has about the most information on haloethylation I've ever seen in one place..
Quote:

The quickest way to a phenylacetaldehyde that I can think of is via a fiedel-crafts with ethylene oxide followed by a careful oxidation of the alcohol. Watch out though, ethylene oxide is a toxic carcinogen. Don't worry about the methoxies, they can take a beating before cleavage.


Hmm speaking of ethylene oxide, I did see where you can react the grignard phenylmagnesium halide with ethylene oxide and then acidify to get phenylethyl alcohol. Don't have too much experience/knowledge about grignards, would this be a useful route? Too bad having to deal with ethylene oxide would make it not very practical..

@Nicodem- I'm only after 2-phenylethylamines, sorry for the confusing posts, a lot of them were written late at night when I was very tired.. I think I'm pretty much done discussing the subject anyway.

[Edited on 1-12-2008 by 497]

[Edited on 1-12-2008 by 497]

Klute - 1-12-2008 at 10:13

Well, i think the major problem would be the ethylen oxide.. Making it and using it (safely)..

Aubrey - 1-12-2008 at 11:10

If one wishes to synth ethyl benzoate from benzoic acid, would denatured ethanol (with methanol) work, or would i get by products. Or alternatively does anyone have details of a source? I cannot seem to find high temp solvents such as ethyl benzoate, decalin or undecane. (uk). I imagine you'd get ethy and methyl benzoate, both of which would be useful as high temp solvents?

[Edited on 1-12-2008 by Aubrey]

Klute - 1-12-2008 at 14:54

Just reflux your denaturated ethanol over some CaO and NaOH to dry it up to absolute and destroy most denaturants, fractionnate it (disgarding the first 5% to remove the methanol-rich fraction), and directly use to esterify (using cat H2SO4, benzoic acid and excess EtOH).
You can even distill part of the excess ethanol during the reaction after a few hours reflux to remove the formed water via the 96% azeotrope, hence the advantage of starting with absolute ethanol.

Better limit the amount of impurities, as I suppose you will not be fractionnating the ethyl benzoate, carbonyls in particulia can be problematic during high temp rearrangement, aswell as amines, etc. even in catalytic amounts.

crazyboy - 3-12-2008 at 16:45

I am making copper sulfate by electrolysis of dilute sulfuric acid with two copper electrodes. I am using DC current (12 volts 1.7 amps.) One of the electrodes corrodes and gives off blue color (copper sulfate) and the other bubbles and collects a spongy red black material which I am quite sure is copper.

I know DC current is almost always used for electrolysis but could I use AC? Both electrodes are the same and I don't care which one makes copper sulfate. If anything I would think I could conserve copper because it would go from electrode to electrode but I wanted to check first because my knowledge of electrochemistry is very limited.

I am using a large transformer initially used to charge a laptop but it gets hot and progress seems to have slowed any advice? Should I add fresh electrolyte?

12AX7 - 3-12-2008 at 19:08

Quote:
Originally posted by crazyboy
I know DC current is almost always used for electrolysis but could I use AC? Both electrodes are the same and I don't care which one makes copper sulfate.


But you do care which one makes copper, and neither will be making either if you run AC. The average is zero.

What you actually need is a seperated cell so that the copper ions aren't reduced by the cathode. They will naturally be drawn to the cathode regardless, making direct electrolysis a poor method of production.

A neutral salt, however, will precipitate Cu(OH)2 (or if hot, CuO, or if Cu(I) is stable in solution (as in a strong NaCl solution), Cu2O), which precipitates with no change to the electrolyte and can be dissolved in a seperate step.
Quote:
I am using a large transformer initially used to charge a laptop but it gets hot and progress seems to have slowed any advice? Should I add fresh electrolyte?


Do what huh??

Tim

hector2000 - 4-12-2008 at 00:05

what is SDA-2B ethanol?

not_important - 4-12-2008 at 00:50

Specially Denatured Alcohol Formula No. 2-B, denatured with rubber hydrocarbon solvent - hydrocarbons boiling between 80 and 120 C, mostly alkanes (ligroin) but at one time including appreciable amounts of benzene and toluene.

A search on-line using your question would have given you that information much more quickly.

raiden - 4-12-2008 at 03:28

Do I have to use a special vacuum oil or is the one used in fridges fine yo?

12AX7 - 4-12-2008 at 03:59

Yo??

Yes, vacuum oil is a specialty oil. You must use it.

Tim

hector2000 - 4-12-2008 at 22:41

what is schema of N-methyl-d,l-alanine and 2 methyl alanine
same?



[Edited on 5-12-2008 by hector2000]

UnintentionalChaos - 4-12-2008 at 23:57

Quote:
Originally posted by hector2000
what is schema of N-methyl-d,l-alanine and 2 methyl alanine
same?[Edited on 5-12-2008 by hector2000]


No. 2-methylalanine (2-methyl-2-aminopropanoic acid) is achiral. N-methyl-d,l-alanine is the racemate of N-methyl-2-aminopropanoic acid.

2-methylalanine is on the left. both enantiomers of N-methyl-d,l-alanine are on the right.

[Edited on 12-5-08 by UnintentionalChaos]

methylalanine.bmp - 142kB

hector2000 - 5-12-2008 at 08:16

what is Eschweiler Clarke reaction
please say with real example with instruction

solo - 5-12-2008 at 08:27

The Eschweiler-Clarke reaction (also called the Eschweiler-Clarke methylation) is a chemical reaction whereby a primary (or secondary) amine is methylated using excess formic acid and formaldehyde.[1][2][3][4] Reductive amination reactions such as this one will not produce quaternary ammonium salts, but instead will stop at the tertiary amine stage. It is named for the German chemist Wilhelm Eschweiler (1860-1936) and the British chemist Hans Thacher Clarke (1887-1972).

........source,

http://en.wikipedia.org/wiki/Eschweiler-Clarke_reaction

hector2000 - 5-12-2008 at 09:14

do you have any example with this reaction?
i want to use it for methylation amine but idont know the ratio of formic acid and formaldehyde and the temp and time.
if some one write a complete reaction of methylation any amine then will be very useful for me
thx

solo - 5-12-2008 at 09:51

There is a thread on methylation where several methods are presented , within each article there is always an experiment example with ratios........also you should try the search function on this forum to see what's been posted... solo

https://sciencemadness.org/talk/viewthread.php?tid=8375&...

https://sciencemadness.org/talk/viewthread.php?tid=7512&...

UnintentionalChaos - 5-12-2008 at 10:11

Has anyone seen anything about the industrial synthesis of piperonyl butoxide? Wiki gives safrole as being a precursor to it, which means they've added the polyalkylether chain to the ring. I want to insert a substituted phenylacetyl moiety in the same spot piperonyl butoxide has the polyalkylether chain and figured any info on the butoxide synthesis might help.

JohnWW - 5-12-2008 at 13:24

Piperonyl Butoxide, or 5-[2-(2-butoxyethoxy)ethoxymethyl]-6-propyl-1,3-benzodioxole, is used as a synergist in cheap aerosol insect killers, and lice-killing preparations, which also contain at least one pyrethroid compound (which are compounds extracted from the African pyrethrum, a species of chrysanthenum, and also occur in some other related daisy species, and synthetic variants of them, usually containing a 3-membered ring). However, it is substantially less lethal to insects than pyrethroids, but much cheaper to make, having been made mainly from safrole since 1947.

The stuff is a potent cytochrome P450 inhibitor. This family of enzymes act as the principal detoxification pathway for many pesticides. Inhibiting the detoxification pathway allows higher unmetabolised systemic concentrations of the active insecticide to remain within the target animal for a longer period.
See:
http://en.wikipedia.org/wiki/Piperonyl_butoxide
http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC33...
http://www.safe2use.com/poisons-pesticides/inerts/piperonyl-...
http://www.the-piedpiper.co.uk/th13(p).htm
http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601105.htm...
http://npic.orst.edu/factsheets/pbogen.pdf
http://www.scorecard.org/chemical-profiles/summary.tcl?edf_s...
http://www.inchem.org/documents/iarc/vol30/piperonylbutoxide...
http://www.medicinenet.com/pyrethrins_and_piperonyl_butoxide...
http://www.chemindustry.com/chemnames/p/piperonyl_butoxide.h...
http://www.elsevier.com/wps/product/cws_home/700827 (review of book about it)
http://www.emea.europa.eu/pdfs/vet/mrls/053798en.pdf
http://www.drugs.com/mtm/piperonyl-butoxide-and-pyrethrins-t...

[Edited on 6-12-08 by JohnWW]

200px-Piperonyl_butoxide.png - 4kB

UnintentionalChaos - 5-12-2008 at 14:06

JohnWWW- basically the links to the first page of a google search? I wasn't looking for general information, but more importantly, what reaction is used to go from safrole --> piperonyl butoxide. I suspect the safrole is hydrogenated first. I am hoping it is or is similar to an FC alkylation, because that would make it very easy to add an acyl moiety instead.

The propyl group on the butoxide will be replaced by a protected 2-hydroxyethyl group.

sonogashira - 5-12-2008 at 14:34

The merck index gives these two patents for the preparation. Also: Science 105, 530 (1947). :)

Seems to use hydrogenation then chloromethylation of saffrole.



[Edited on 5-12-2008 by sonogashira]

JohnWW - 5-12-2008 at 15:07

Here are the details of the book that has been written about the stuff:

Piperonyl Butoxide - The Insecticide Synergist (Academic Press - 1998)
by Denys Glynne Jones, Glynne D. Jones, Denys Glynne Jones (Hardcover)
http://www.springerlink.com/index/Q54R2K270TU212N4.pdf (need paid subscription to access)
http://doi.wiley.com/10.1002/(SICI)1526-4998(200001)56:1%3C101::AID-PS91%3E3.3.CO;2-V

Piperonyl Butoxide contains 20 chapters contributed by world experts in the field on the properties, uses, plant metabolism, and mammalian and environmental toxicology of piperonyl butoxide. The mode of action of piperonyl butoxide is discussed as well as many other specialist topics, including the measurement of synergism in the laboratory, and the potential use of this chemical alone for the control of whiteflies, as well as with insect growth regulators.
This book will prove to be a valuable reference for all concerned with the designing of safe and cost-effective insecticide formulations, particularly those used in the home, industry, or on or near animals and food.

Found on Gigapedia at: http://gigapedia.org/items/199506/piperonyl-butoxide
The Rapidshare download link has been posted in the References section, under Organic Chemistry books.

[Edited on 6-12-08 by JohnWW]

9780122869754-PiperonylButoxide-DGJones(Springer)-cover.jpg - 5kB

hector2000 - 5-12-2008 at 23:19

i have 2 question:
1-does norephedrine will methylate by aluminum amalgam+formaldehyde+Etoh--->Ephedrine or psudoephedrine?

2-in the industry for make large scale of psudoephderine use of lpac and then reduce lpac to psudoephedrine but making lpac need pyruvic acid that is expensive.i wonder if in the industry use pyruvic acid how the price of psudoehedrine is cheap!!

[Edited on 6-12-2008 by hector2000]

crazyboy - 6-12-2008 at 00:11

Gonna cook up some amphetamines or do you just have stuffy sinuses?

hector2000 - 6-12-2008 at 00:38

i am not cooker or another thing
just i am interesting to know it

Picric-A - 6-12-2008 at 05:42

Does anyone know what is in those little 'O2 ABSORBER' sachets you find in packs of tea leaves?
My guess would be alkaline pyrogallol but i cant be sure,

497 - 6-12-2008 at 13:42

Iron powder works for that purpose but I'm not sure if that's what they are.

Picric-A - 7-12-2008 at 02:13

I thought that but upon testign with a maggnet it proves wrong.
I am going to dissolve it in water and test the PH.
edit- PH is neutral, now im clueless :(

[Edited on 7-12-2008 by Picric-A]

crazyboy - 7-12-2008 at 11:50

I have been thinking about getting some good quality chemicals. I have been scrounging and making my own stuff for a while and I want some real lab grade stuff with known purity.

So my question is who will ship to me. I don't have a company just an individual my question is what is the best company that has good prices and ships top individuals? I have heard a lot of people here buy from big names like Fisher, Sigma Aldrich, Spectrum and Acros. But I have also heard they only sell to big companies.

So who sells reasonably priced high quality chemicals to individuals ad hobbyists? Does anyone?

Nicodem - 8-12-2008 at 01:44

Your question is impossible to answer with a simple reply. There already is a thread about the topic and I suggest you to read trough it very carefully since the answer is very complex and extremely geography dependent. While still doing experiments at home, I used to get chemicals trough various sources (like friends, hardware stores, etc.), but I also bought many from chemical suppliers. I never bought directly from what you called "big names", but always ordered from the chemical resellers. This is also the way the university labs and most research labs do in this part of Europe. Things might be very different if you live in the USA or other parts of the world or so I heard from others, but I never heard of anybody ordering directly from the Sigma-Aldrich-Fluka conglomerate, for example. Some minor "big names" companies like Alfa-Aesar or Abcr that do not have official local representative offices do sell trough direct orders, but you will probably have to open an account with them which is not really worthy if all you want to order is just a couple of things - in this case rather go trough a local reseller of chemicals (it will cost you slightly more, but still much better that trying to deal with big companies as an individual).

raven - 8-12-2008 at 06:40

hello everybody,would liquid parrafin from a chemistshop be o.k to submerge lithium metal in.i have just got a reasonably sized sample of lithium.but the metal is poking above the oil line leaving a fare bit exposed.
i wanted to top the oil up to the brim to completely submerge it.would liquid parafin be o.k to use as is?i think its called mineral oil in the states ,im from the u.k.

12AX7 - 8-12-2008 at 07:47

Yes.

raven - 8-12-2008 at 09:41

thanks thats what i thought,but always good to get a second(3rd,4th,5th) opinion

cheers :D

Klute - 8-12-2008 at 10:03

Yes, yes, and yes :)

Picric-A - 8-12-2008 at 13:40

Dont forget you can submurge Lithium easily becuase it floats on top of practically everything.the only way you can do it is use a small bottle and fill it with oil to the brim.
I have always boiled the oil i use to store my Lithium to 200 degrees C then leave to cool in a dessicator to make sure there is no traces of O2 or H2O dissolved. That may be being a bit cautious though :P

Picric-A - 10-12-2008 at 11:17

Just a quick question.
I plan on making some Raney Nickle for hydrogenations.
To do this you make a nickle/aluminium alloy then dissolve in NaOH to give the Raney nickle.
I know nickle has a high melting point but aluminium doesnt. Does anyone know if i melt aluminium will the nickle dissolve in the aluminium or will it need to be hotter?
cheers

raven - 10-12-2008 at 12:55

i toped it up with liquid parafin,it worked perfectly.i was concerned that it might have contained a tinybit of water,so i tested 1st with just a tiny bit of lithium in some parafin ,no hydrogen formed,so i figured it was all o.k...and it was.
thanks for your replys,always helpful to be reassured

smuv - 10-12-2008 at 15:18

Picric, If you need to prepare the alloy, you might be better off with an Urushibara nickel catalyst.

That being said, I am sure if you look hard enough, you must be able to find a source of a nickel aluminum alloy.

Also, for the home experimenter Pd/C is seriously worth reconsidering as it is readily available from photo supplies and requires much lower temperature/pressures. I bought 50g of 20% Pd/C off of ebay for next to nothing, it came sealed in its original container.

P.S. If you don't get a good answer here, check out, http://www.backyardmetalcasting.com/forums/, I know you will be able to get a reasonable answer there.

12AX7 - 10-12-2008 at 16:51

Nickel and aluminum are -- what's that word? At any rate, the intermetallic formed is exothermic. It suffices to heat aluminum and nickel filings together. When the aluminum melts, it dissolves some nickel, decides it has a taste for it and heats up, keeps on dissolving and etc. A flux would help the aluminum make contact with the nickel, but would also evaporate (leading to gas production) when the stuff goes off...

Tim

Carbonyl Chloride?

smuv - 10-12-2008 at 17:28

If I stir a mixture of tetrachloroethylene water, and TCCA for a few hours, seperate the layers and then treat the organic phase with an alkali solution is there ever any chance of appreciable carbonyl chloride production?

I see no obvious method for its formation, but I have seen it pop up in some very mild oxidations of tetrachloroethylene, so I want to pass it by the forum.

Thanks.

PS Trichloroacetic acid is the desired product...

Nicodem - 11-12-2008 at 00:30

No phosgene should form. However, tetrachloroethylene is a very electron poor alkene and will take a long time for it to react in an electrophilic addition and under biphasic conditions (actually triphasic since TCCA is also poorly soluble in both, water and tetrachloroethylene). I suggest you to use acetonitrile as cosolvent (85% acetonitrile/water should do) and leave it running for several days (do not use acetone as HCl forms during the reaction and will catalyse the alpha-chlorination of acetone). A homogeneous reaction will also prevent side reactions (like for example the addition of Cl2 forming hexachloroethane due to absence of H2O in the organic layer rather than forming trichloroacetic acid). Do you have any related literature examples on halohydration of tetrachloroethylene? It appears to me that electrophilic reactions on tetrachloroethylene are not particularly rapid.

gnitseretni - 11-12-2008 at 08:02

Some folks make their own fuses with black powder. I don't have black powder, but I do have sodium nitrite, hexamine and sulfur. Could I use my sodium nitrite as a substitute for the potassium nitrate and hexamine for the charcoal and is there a way to calculate how much I need to use of which?
Any help would be appreciated.

not_important - 11-12-2008 at 08:10

Sodium nitrite is not as good of oxidiser as the nitrate, and with both of those the sodium salts are somewhat hygroscopic and so tend to get damp if exposed to the atmosphere.

Charcoal is so easy to get I'd try just a bit to get or make some and use it. Rather pure charcoal can be had by baking plain sugar, there's even a preparation in Inorganic Synthesis volume 2.


[Edited on 11-12-2008 by not_important]

hissingnoise - 11-12-2008 at 08:22

IIRC, NaNO3 is very hygroscopic (not sure about the nitrite); hexamine is a weak base *and* hygroscopic.
I'd say the mix would be very unpredictable, at best.

gnitseretni - 11-12-2008 at 12:37

if I were to leave the sodium nitrite in the open, how long would it take for it to turn into the nitrate? Hours, days, weeks? And is there a test I could to tell the two apart from each other?

Filter Paper dryness

Panache - 11-12-2008 at 12:58

I just thought about my collection of whatman filter papers this morning and wondered if they are at all hydroscopic and/or gas adsorptive and if so does that mean for sensitive to water/O2/CO2 work should the papers be kept in a vacuum dessicator, that would be sooooo convienent.
thanking people in advance
mark

smuv - 11-12-2008 at 14:10

@Nicodem, I have searched and I do not. I suspect though the halohydrin is unstable and readily rearranges to the epoxide/carboxylic acid. I agree though, tetrachloroethylene should be an unreactive substrate, but I still think it is worth a smallscale shot.

Is TCCA so insoluble in tetrachloroethylene? I recall seeing TCCA reactions done in DCM (albiet more polar than tetrachloroethylene) without co-solvent, so I thought the solubility in tetrachloroethylene wouldn't be SO bad.

The best method to do this, would be to pass oxygen through tetrachloroethylene for a few days at elevated temperatures, and I might end up doing that if I fail with the TCCA method.

Of interest, the product of the rearangement of the epoxide in anhydrous conditions is trichloroacetyl chloride.

For more info about the reaction with oxygen see US2321823, and 'Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 11, pp. 1849-1852.' linked below.

PS whether or not it is prudent, halohydrin formation in aqueous acetone is known to litterature...that being said, on a preparative scale I would be nervous to try it.


[LATE EDIT] Ok you were right :P TCCA seems to be pretty insoluble in tetrachloroethylene...I am still giving it a try w/o cosolvent because I don't have acetonitrile on hand (I should really order some).

[Edited on 12-12-2008 by smuv]

Attachment: oxidation_bromovinyl_compounds_molecular_oxygen.pdf (119kB)
This file has been downloaded 784 times

octave - 11-12-2008 at 14:14

I'm helping out a friend come up with a project that involves chemistry and basic calculus or trigonometry(He wants sin, cos, or tan in an equation that is used in chemistry), but have come up with nothing. Could anyone help me out?
 Pages:  1    3    5  ..  7