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All 27 posts Subject: 1st experience w/ Hydratropic Aldehyde -> P2P Please login to post Down

xspikehead
(Stranger)
08-29-03 04:16
No 456276
      1st experience w/ Hydratropic Aldehyde -> P2P

Swix added 90ml hydratropic aldehyde dropwise over a period of 1 hr to 400ml sulfuric acid chilled to -10-13 C with constant stirring. Solution quickly turned dark brown when first drops of aldedhyde were added. After 90ml aldehyde was added, solution was left another 15 min (putting the total time at 75 min). Poured onto 5lbs cracked ice, let resolve to room temp, extracted w/ 300ml toluene, washed organic phase w/ water. Then performed atmospheric distillation of the toluene - collected 300ml of it. Was left w/ a thick dark-golden color product in the reaction flask - about 40-50ml worth. This I THINK is P2P, but it is rather THICK and somewhat DARK... it smells like SOMETHING - kinda aromatic, a little potent... tried performing the sodium bisulfite test but to no avail due to the thickness of the ketone.

Swix understands that this is not the most popular route to P2P, but if anyone had anything to advise - to confirm if this is or isn't P2P, or what to do differently for the future, swix would greatly appreciate it.

xspikehead
(Stranger)
08-29-03 22:30
No 456403
      SwiX would greatly appreciate a response to...

SwiX would greatly appreciate a response to this synth SwiX attempted twice, because SwiX fears P2P is not his finished product... but he is hopeful!

90ml hydratropic aldehyde added dropwise to 400ml sulfuric acid for 60 minutes, let react another 15 more minutes. Stirring was used throughout, temperature was maintained around -16 C. Poured onto 5lbs cracked ice. Molten ice was treated w/ 300ml toluene to pull P2P into the toluene. Washed tol/P2P once w/ water and once w/ dilute sodium bicarbonate solution (to remove sulfuric acid). Poured mixture into reaction flask, distilled off the 300ml toluene originally added, and SwiX is assuming the 40-50ml residue in the flask (thick oily liquid, golden color) is P2P.

Only problem is, SwiX has heard that P2P is a clear to pale-yellow liquid.... this is MUCH more an oil than it is a liquid. And secondly, why, when SwiX reads writeups on this process, is the P2P distilled over? If all SwiX pours in the reaction flask in the first place is the tol/P2P, isn't there just P2P left once SwiX distills off the toluene? SwiX believes this, especially since he washed the tol/P2P phase w/ water followed by a dilute sodium bicarbonate solution.

A response would be most appreciated.

terbium
(Old P2P Cook)
08-30-03 00:14
No 456415
      Vacuum distill

If this reaction works, I would expect it likely to give you also a lot of polymerized junk along with the P2P. Your best hope will be to vacuum distill after stripping the toluene from the bicarb washed extract.

All those moments will be lost in time, like tears in rain.

java
(Hive Bee)
08-30-03 00:28
No 456420
      RE: Hydrotropic Aldehyde....
(Rated as: good read)

Did you happen to read this.......java

https://www.rhodium.ws/chemistry/phenylacetone.html

Exerpt
........It is not possible to effectively separate 2-phenylpropanal (bp 222°C/760mmHg) from phenyl-2-propanone (bp 214°C/760mmHg) through simple distillation and certainly not via vacuum distillation as the boiling points are too close. Fractional distillation could theoretically be used to separate them, but the size of the column that would have to be used makes that option impractical. A good idea for separating a mixture of the two is to oxidize the mixture with a mild oxidant which won't affect the P2P, but which will oxidize the aldehyde to 2-phenylpropionic acid. The acid can then be separated from the ketone by dissolving the mixture in a non-polar solvent and washing the solution with dilute sodium hydroxide. The P2P stays in the organic layer, which is then dried over MgSO4, the solvent removed under vacuum and the residue vacuum distilled to give pure P2P.

Also,....

Post 446496 (Rhodium: "Phenyl-2-propanal to P2P", Russian HyperLab)

Post 446720 (Timmy: "So it is...", Russian HyperLab)

Post 446886 (Rhodium: "Thanks for the translation", Russian HyperLab)

there is also much more that can be found on the search engine so dig, dig, and you will find your answers.......java

We're all in this world together,
http://www.chiapaslink.ukgateway.net/

xspikehead
(Stranger)
08-30-03 00:33
No 456422
      Did just that, can't tell the difference...

A vacuum distillation made it into a golden liquid upon entering the receiving flask, only to thicken up to an oily-consistency soon thereafter. This synthesis has been mentioned a few times on this site, on Rhodium's, and in Uncle Fester's new book, so it MUST work to some degree. But it makes me wonder why this isn't a more popular route to synthesizing P2P. Hydratropic aldehyde is easy to obtain from the U.S. suppliers, so that makes me wonder a bit.

java
(Hive Bee)
08-30-03 02:21
No 456435
      RE: Hydrotropic Aldehyde....

Well it works as you know , but then let's just fine tune it and not worry about why more bee's don't go this route.......we don't want it to go the way of ephedrine in it's prohibition. So get your methylamine and finish it up and do a write up so other bee's can keep refining the technique....java

We're all in this world together,
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java
(Hive Bee)
08-30-03 17:04
No 456493
      RE: 1st experience w/ Hydratropic ...
(Rated as: good read)

As stated in the rhodium article , fractional distillation will not work because of the proximity of both temp of products hence it is recommended .........anyway read the post's included.....also stuff about the creamy stuff you got in Jan's thread.....java

Post 319753 (Jan1983: "Succsess story: 85ml H2SO4 96% 18ml Hydratropic ...", Stimulants)

Post 409033 (Rhodium: "Separating 2-phenylpropanal and phenyl-2-propanone", Stimulants)

Post 409076 (Rhodium: "Read up some more first, you are confusing a...", Stimulants)

Post 319331 (Jan1983: "P2P from 2-Phenylpropanal > 2-PHENYLPROPANAL ...", Stimulants)

Edit: try to post the references you've found in support of your method......all the stuff I've mentioned could have been found in the hive search option....try.... 2-phenyl propanal, Hydrotropic aldehyde, 2-phenylpropanal

We're all in this world together,
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java
(Hive Bee)
12-12-03 22:47
No 476486
      RE: Hydratropic aldehyde.;.....

Here is some stuff Lugh posted on the synthesis of 2-phenylpropanal (hydratropic aldehyde)......

Post 427944 (lugh: "Hydratropaldehyde", Stimulants)

and more recently azole worked hard to provide the article were P2P is converted from 2-phenlpropanal under reflux with dilute H2SO4 in good yields....

Post 476441 (azole: "as requested by java", Russian HyperLab)

just updating the info on this process for all the bee's interested ........java

Note..there is a reference that would be appreciated ......

Preparation of 2-phenylpropanal by catalytic addition of Hydrogen and Carbon Monoxide
Adkins and Krack
JACS 70 383 (1948)

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Rhodium
(Chief Bee)
12-12-03 23:20
No 476493
User Picture       Catalytic Hydratropic Aldehyde

Preparation of Aldehydes from Alkenes by the Addition of Carbon Monoxide and Hydrogen with Cobalt Carbonyls as Intermediates
Homer Adkins, George Krsek
J. Am. Chem. Soc. 70, 383-386 (1948) (https://www.rhodium.ws/pdf/p2pal.pdf)

The Hive - Clandestine Chemists Without Borders

roger2003
(Hive Bee)
12-13-03 16:48
No 476616
      Hydratropaldehyde

The JACS procedure was not successfull (yield and poisen pp) an there was found a better way:

Patent GB1255537

Abstract:

Phenylpropanals. RUHRCHE- MIE A.G: 27 June, 1969 [24 July, 1968], No. 30083/69. Heading C2C. Phenylpropanals are obtained by hydro- formylating styrene with CO and H 2 at 80- 200 C. and 50-500 atmospheres pressure in the presence of a rhodium catalyst containing 0А05-0А000125% by weight of rhodium based on the styrene. The phenylpropanals can be hydrogenated to phenylpropanols, either with CO and H 2 without the separation of the rho- dium catalyst or the addition of another catalyst, or in the presence of a copper chromite catalyst.

See also german patents:

Patent DE1793017
Patent DE1939322

.

roger2003
(Hive Bee)
12-14-03 11:23
No 476755
      Isomerisation, Polymerisation

In Ber 60, 1050 (1927)the converting-procedure from a-Phenylpropanal to P2P is discussed.

The yield is 62% of isomerisation-product (with H2SO4 at -16°) and the rest is a polymerisation product.

The combined products (7,2 g from 9 g a-Phenylpropanal) are distilled at 11 mm (Hg):

91-92° = 1   g
92-94° = 2   g
94-96° = 2,6 g

and there was a (polymerisation) residue from 1,6 g

roger2003

java
(Hive Bee)
12-14-03 23:57
No 476861
      Re: 2-phenylpropanal conversion to P2P

Well so far it's been proven that the conversion works both in the literature , In Ber 60, 1050 (1927, and the article provided by azole...and in the most recent past , actual hands on experiments posted by Jan1983 not only provided his results as well as a now missing post Post 331698 (Jan1983: "largescale p2p", Stimulants) ...."largescale P2P" in which he describes and gives his result on a large scale run. As far as the synthesis the stating material , 2-phenylpropanal , all the procedures seem a bit difficult and involve some nasty chemicals.

The reflux method ,as noted in the article Azole provided, it seems the process with dilute H2SO4 works with better yields and avoids the large amount of acid and low temp. However the finish product still needs to be oxidised to remove the unprocessed 2-phenylpropanal and washed with a dil. NaOH solution, hence the end solution will be w/o and removed with Toluene to get cleaned P2P.

I think there is a way to re arrange styrene in the presence solvent X such that 2-phenylpropanal is the result product......ofcourse this is just a suspicion based on no facts , maybe wishful thinking .If that was the case we would have a very easy OTC method to P2P .. so the search continues......java

Edited Just as I posted this Roger2003 posted this.....
Post 476771 (roger2003: "Hydratropaldehyde", Chemistry Discourse)

so it seems that the process Xis starting to show it's face ....got to go read it now...java

We're all in this world together,
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roger2003
(Hive Bee)
12-15-03 11:17
No 476967
      Hydratropaldehyde

The from Azole provided article has the same authors like Ber. 60, 1050 (1927) - Danilov - Danilova

In Ber. 60, 1050 is also described a process with HgCl2 and higher yields (80%), but they have a mixture of P2P and a-phenylpropanal.

The oxo-process, starting from styrene, needs CO and H2 with a catalyst.

If you want to work without pressue (CO and H2) you have to start from a-methylstyrene and convert this to the corresponding Oxide (epoxide)

This epoxide you can convert directly to P2P (with H2SO4 at -16° -low yield) or to a-phenylpropanal by distilling (high yield).

There is another way directly from a-methylstyren to P2P (with Thalliumsalts) The references you will find in my posted artice (in your thread)

This method needs only a-methylstyrene and thallium(III)salts and no other chemicals, but you have to convert the thallium(I) salts to thallium(III) salts. This is possible in differnt ways.

.

CheshireHouse
(Hive Bee)
06-23-04 07:57
No 514933
      swim's attempt

720ml H2SO4 chilled to -20C. Added 162ml 2-phenylpropanal dropwise, at rate so as to keep temp below -16C, with good stirring. Allowed to remain chilled & stirred for unknown amount of time (fell asleep) but probably about a couple of hours.

Resultant mixture was dark brown. Poured onto some ice (but not nearly as much as recommended, as had only a small amount of distilled ice & didn't want to use non-distilled ice).   Seemed to turn a little white at first but remained mostly dark brown. Contained a large, lumpy, polymerized mass.

Added equal volume toluene, stirred well. Toluene picked up dark brown color, dissolved polymerized mass.

Distilled toluene at atmospheric pressure. Distilled remainder at 24mmHg, got no fraction close to proper temp. Did not continue to distill, gave up when realized temp was far too high for it to be p2p. What was left, after return to atmospheric pressure & turning off of temp, was black and formed a solid brick in the bottom of the flask.

Anybody have any tips for SWIM on where she went wrong? Not using enough ice significant? Would appreciate thoughts.

Thanks! :)

jen

knowing is the easy part

amalgum
(Hive Bee)
06-23-04 18:55
No 515008
      Cheshirehouse: You didn't say anything about...

Cheshirehouse:
You didn't say anything about washing the toluene with carbonate first before distilling. SWIM thinks since you didn't do that traces of sulfuric is what fucked it all up (polymerization).
Plus you people are just not listening. Your gonna have to use a mild oxidant before distillation. Your not gonna separate the unreacted aldehyde by distillation dammit. There are plenty of very cheap otc oxidising reagents you could use for this. Then extract back into toluene and wash again with a carbonate to convert all the hydratropic acid you just made from the left over aldehyde to a water soluable sodium salt. Then it's ready for distillation.

Come-on. SWIM has been reading about this route for a long time. It seems to be well documented. Just how much research do you all actually do before trying something?

CheshireHouse
(Hive Bee)
06-23-04 21:25
No 515040
      OK about washing with the carbonate.

OK about washing with the carbonate.

As for making sure the P2P was able to be separated from any unreacted aldehyde, I first wanted to see whether I was getting anything at all. Despite not being able to separate the close fractions, I figured I'd see whether I was getting any fractions in that range at all. Since I didn't, I'm glad I didn't waste the time.

Another question I had was, does anyone know what (if anything) happens to 2-phenylpropanal when reacted with methylamine? If nothing, then why not just leave it mixed? Or, if it does, is it easier to separate whatever the reaction product is from methamphetamine than it is to separate the aldehyde from P2P?

Thanks for your reply! :)

jen

knowing is the easy part

CheshireHouse
(Hive Bee)
06-23-04 21:33
No 515045
      Also, the polymerization [UPDATED]

Also, the polymerization appeared to occur long before I attempted to distill the mixture... as I noted above, there was a huge, gummy mass that formed after having poured the reaction product over ice & having let it melt. It did dissolve into the toluene when I added it, but I would think that it was too late at that point to wash out excess sulfuric with hopes of avoiding polymerization... unless I'm completely wrong about what that gummy mass was, which is entirely possible.

Has anyone else observed this formation of a large, gummy mass at the point when the reaction product was added to ice?

//edit: from what I remember, Rhodium originally mentioned having to separate the p2p from the aldehyde in connection with the alpha-methyl styrene synth, which gave a 45% yield of p2p & 55% hydratropic aldehyde (or vice versa). In fact, he mentioned the synth under discussion here as a possible way to convert the remaining aldehyde. So does anyone have any evidence that there's even any unreacted aldehyde left after reacting the aldehyde with the H2SO4 in this synth, that would need to be dealt with? Or did everyone just take Rhodium's comment regarding the other synth & run with it?

In fact, one of the translated articles says "In the case of concentrated sulfuric acid the yields were sometimes reduced because of formation of condensation products; the reaction products didn't contain the starting aldehyde. The experiment is carried out as follows: to sulfuric acid (sp. grav. 1.84) cooled to -20° or to -10° an aldehyde is added with stirring...". This would seem to confirm that in the case of using concentrated sulfuric at -20, there's no need to worry about any unconverted aldehyde.

jen

knowing is the easy part

java
(Hive Bee)
06-24-04 02:26
No 515091
      References please

CheshireHouse Could you please list the references you keep quoting so I can understand where you are coming from with your analysis of the reaction....java

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amalgum
(Hive Bee)
06-24-04 04:15
No 515106
      This is from: https://www.the-hive.ws/forum/sho...

This is from:
Post 319139 (Jan1983: "P2P / Hydratropic Acid", Stimulants)

(Sorry, very limited html knowledge, so somebody could please fix that link. I beleive it was posted earlier anyway in this thread. It took only five minutes to look it up with TFSE)

Rhodium
(Chief Bee)
06-10-02 03:13
No 319315
   Purification is a MUST!   Bookmark Reply

If you subject hydratropic aldehyde to an Al/Hg reductive amination with methylamine, you will get N-methyl-2-phenylpropylamine, which to my knowledge is not tested in humans and is possibly toxic.

You must certainly remove all the aldehyde from your P2P before continuing. Ask Osmium about what OTC oxidant you should use, he must know what would work best for that.

It is not possible to effectively separate 2-phenylpropanal (bp 222°C/760mmHg) from phenyl-2-propanone (bp 214°C/760mmHg) through simple distillation, and certainly not via vacuum distillation as the boiling points are too close. Fractional distillation could theoretically be used to separate them, but the size of the column that would have to be used makes that option impractical.

(Never mind, the link fixed itself, hell yeah cool )

CheshireHouse
(Hive Bee)
06-24-04 06:39
No 515118
      Sorry about that.

I brought up the synthesis from alpha-methyl styrene a few years ago, in this thread: Post 43910 (CheshireHouse: "alpha-methyl styrene", Serious Chemistry). A year or so later, Rhodium made the comment I was referring to about the inseparability of the aldehyde & p2p, in this one: Post 314878 (Rhodium: "Method choice", Chemistry Discourse).

The quote I made comes from here: Post 476441 (azole: "as requested by java", Russian HyperLab). He also says, even more to the point,
The transformation of aldehydes to ketones occurs easily under some heating in the presence of mercuric salts and especially easily, one may say, immediately, under the action of concentrated sulfuric acid with cooling. In this process, mercuric salts and concentrated sulfuric acid form loose complexes with the reactants and the reaction products. The end-products of the reaction (ketones) form more stable complexes than aldehydes do. This accounts for the fact that only ketone can be found in these complexes, especially in the case of concentrated sulfuric acid.

So it seems to me that in the particular reaction under discussion, i.e., reaction of 2-phenylpropanal with conc. H2SO4 at low temp, there should be none of the original aldehyde present -- and therefore no reason to worry about how to separate it from the p2p.

Hope that covers everything I quoted from, if not let me know. :)

p.s. sorry if the links point to a post instead of a thread, I can't get them to work the way I want them to :/

jen

knowing is the easy part

CheshireHouse
(Hive Bee)
06-27-04 00:33
No 515642
      opinions?

Does anyone have any thoughts on 1) Whether my interpretation of the article quoted in the post above is correct, and 2) Whether, if so, there might be other close-boiling fractions present other than the aldehyde, and what they might be (I ask because of xspikehead's first two posts in this thread, where he seems unsure that what he got was pure P2P, even after distillation).

Appreciate your comments.

jen

knowing is the easy part

CheshireHouse
(Hive Bee)
07-02-04 02:13
No 516835
      another attempt

OK. SWIM used the proper amount of ice this time, and with the acid suitably diluted by the melted ice, the reaction product did turn from brown to white, as it should have.

There is a good amount of yellow-whitish lumpy stuff, which SWIM thinks is some sort of sulfur compound, as there were what looked like sulfur clumps stuck to the inside of the flask after the reaction.

After extract with toluene, water wash, bicarbonate wash, attempted distill. (Did not attempt to remove unreacted aldehyde, as there shouldn't be any left, according to the journal I quoted above, and because it doesn't smell at all like the aldehyde, which has a distinctive odor.) While distilling off the toluene, the mixture suddenly turned to a darker color... not as dark as the original brown, but sort of a reddish dark gold. After distilling the toluene at atmospheric pressure, SWIM did a vacuum distillation on the dark liquid which remained.

The russian article says that "condensation products" form, causing the dark brown color, but that they break up when the acid is diluted, allowing the p2p to be isolated. That did appear to happen. But then it seemed they reformed. I'm not sure why that would happen, since I had washed the toluene, so there shouldn't have been more sulfuric left to form more of these condensation products.

Any suggestions?

jen

knowing is the easy part

java
(Hive Bee)
07-02-04 03:50
No 516862
User Picture       Oxidation needed.....

It was recommended to use to oxidation here are some quotes.......

To separate 2-phenylpropanal from phenyl-2-propanone you first need to oxidize the 2-phenylpropanal to 2-phenylpropanoic acid (perhaps with basic potassium permanganate or dilute potassium dichromate), then you can wash it away with aqueous base

....as read from Post 409076 (Rhodium: "Read up some more first, you are confusing a...", Stimulants)

a mixture of 2-phenylpropanal and phenyl-2-propanone? In that case, mild oxidation of the aldehyde to the acid shouldn't disturb the ketone, and the formed acid can be extracted as the sodium salt with 10% aqueous sodium carbonate, while the P2P will stay in the organic layer.

.......as read from Post 409033 (Rhodium: "Separating 2-phenylpropanal and phenyl-2-propanone", Stimulants)

It is not possible to effectively separate 2-phenylpropanal (bp 222°C/760mmHg) from phenyl-2-propanone (bp 214°C/760mmHg) through simple distillation and certainly not via vacuum distillation as the boiling points are too close. Fractional distillation could theoretically be used to separate them, but the size of the column that would have to be used makes that option impractical. A good idea for separating a mixture of the two is to oxidize the mixture with a mild oxidant which won't affect the P2P, but which will oxidize the aldehyde to 2-phenylpropionic acid. The acid can then be separated from the ketone by dissolving the mixture in a non-polar solvent and washing the solution with dilute sodium hydroxide. The P2P stays in the organic layer, which is then dried over MgSO4, the solvent removed under vacuum and the residue vacuum distilled to give pure P2P.

......as read from https://www.rhodium.ws/chemistry/phenylacetone.html

so you see even though you can't smell it it's gumming up the end product you want, Jan 1983 claims even in his large scale production ,post not existing , that he got good results without oxidation to salt out the aldehyde as an acid, but then he's not around to answer as to what he did.....java

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CheshireHouse
(Hive Bee)
07-02-04 04:28
No 516878
      I know this. But all of these assume that...

I know this. But all of these assume that there is still aldehyde left in the solution. Did you read my response to your request for references, above? The last article, the Russian one from the "requested by java" thread, clearly says that none of the original aldehyde remains when using the conc. sulfuric / low temp variation of this reaction. It mentions the fact several times.

I actually suspect that SWIM's bicarbonate wash was not sufficient. Testing the pH of a final water wash should tell whether any acid remains. A sulfur odor is detected in the final distillation product, SWIM has noted, so I'm thinking that the sulfuric residue caused the stuff to re-polymerize, or re-form the condensation products, or whatever it is doing, during distillation.

Well, guess SWIM will have to try again, and be more careful this time.

jen

knowing is the easy part

roger2003
(Hive Bee)
07-02-04 05:06
No 516889
      Ber. 60, 1050 (1927)

In Ber 60, 1050 (1927) they add 6 g Aldehyd to 30 ml conc. H2SO4 at -16°C in 35 minutes. Than this mixture was standing for 15 minutes under cooling to -15°C and than poured on ice. (Yield 48%)

In another experiment they take 9 g Aldehyde to 40 ml conc. H2SO4 under the same conditions (Yield 62%)

So I think it is at first a question of the time for adding (35 minutes) and standing (15 minutes) with a minimum (better cooling) of H2SO4

If you work with 100 g Aldehyde you have to do this also in 35 + 15 minutes.

roger2003

java
(Hive Bee)
07-02-04 14:49
No 516959
User Picture       The cooling time factor.....

Roger2003 You are correct in pointing this out , interesting that sometimes the smallest part in a synthesis can show it's ugly face with some unwanted results! I was sold on the comments of oxidation but completely overloooked the time factor .....

after addition of H2SO4, let it stand on stirring for 3 hrs. then take the cap off ,a large vessel used to react the acid with the aldehyde, and take the 25 liter vessel and pour everything into the 100 liter ice bucket.....fine , now wait until ice has melted, then add 10 liters of Toluol seal the large vessel and try to shake it with 2 perons or kick it around or do anything to mix the layers. then siphon of or take an adequate separator and separate the tolly, , repeat again with 5 liters and then again with 9 liters, vacumm distill the tolly then the loved stuff now you have not high purity P2P I think but it's ok for Al/Hg/Nitro. My yield was 53,98% of the method with 4 liters Hydrotropic aldehyde

............as taken from Jan1983 "Large scale P2P" post # 331698, not longer in existance at the hive.
..........and again repeating what Roger2003 pointed out .Post 319331 (Jan1983: "P2P from 2-Phenylpropanal > 2-PHENYLPROPANAL ...", Stimulants)

I would also like to point out that the old Ref to the Danilov article that Azole so kindly translated was first mentioned to my knowledge, by Jan 1983 as quoted from the same post above.

Does anyone have any thoughts on 1) Whether my interpretation of the article quoted in the post above is correct, and 2) Whether, if so, there might be other close-boiling fractions present other than the aldehyde, and what they might be (I ask because of xspikehead's first two posts in this thread, where he seems unsure that what he got was pure P2P, even after distillation).
"......from CheshireHouse post , I'm not trying your patience only giving you my thoughts of some small thing you might have missed, as you asked, I included a part of Jan1983 post to further support roger2003 point , as to the waiting period, as it was done in a larger scale.........java

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CheshireHouse
(Hive Bee)
07-14-04 08:14
No 519349
      re: cooling time factor

I guess that's possible. Though I can tell you from SWIM's experience that 2 different reactions, one in which the HTA was added over a much longer period, & allowed to stir for longer as well, seemed to yield identical results, as far as SWIM could tell.

The Danilov article mentions the formation of condensation products, which break down when the acid is diluted. SWIM definitely noted that upon pouring the reaction product over crushed ice the dark brown color disappeared, to be replaced by some sort of whitish stuff that wasn't soluble in water (nor in the dilute acid mixture). The stuff looked sort of like you'd imagine little pieces of white bread might appear after they had been floating in a jug of water for so long that they'd broken down into little semi-fibrous drifting stuff (note the high-tech analytical descriptive analogy I so skillfully deployed there ;) ).

When toluene is added, it dissolves the whitish stuff, which seems like it could definitely be problematic, as whatever it is (I assume some sort of by-product of the breakdown of the "condensation products", but I don't know what it is) is now mixed in with the P2P which is hoped to be there. So I wonder if it might be filtered out before the toluene extraction.

But I also wonder whether it might be bonding to the P2P to some extent -- because otherwise I would think that the P2P would separate from the dilute sulfuric solution... but leaving a sample of the reaction product / dilute sulfuric solution overnight did not show any separation (note, however, that the whitish stuff was not removed before letting it stand).

I have a feeling that this stuff is floating around in there with the P2P, and then after the solvent is removed, and with further heating during distillation, some sort of complex is reforming. It definitely seemed like there was a sudden reversion to the brownish color while trying to distill the P2P from what was left after removal of the toluene.

I note that Jan1983 (and it seems as if someone else said the same thing in another post, I'm not sure) just used the crude product left after removal of the toluene as if it were the pure product, in completing the synth to meth. Maybe that's the way to go, as I suspect that the water/alcohol mixture used in the standard methylamine/P2P synth would inhibit the formation of the unwanted gunk (SWIM's attempted distillation of the reaction product after the HTA/H2SO4 synth left a rock-hard amberish substance glued to the bottom of the flask, which only seemed to dissolve completely in acetone. Upon pouring out the acetone into the sink, SWIM observed that the acetone with the dissolved gunk in it, which was a dark reddish-brown color, immediately turned white upon mixing with some standing water in the bottom of the sink... my take on this is that these same "loose complexes" that were broken down when pouring the reaction product over ice & allowing it to melt, reformed once they were free of the water & able to come into contact with the P2P again (when taken up into the toluene). Washing the toluene with water didn't help; but when in the acetone, which is miscible with water, water again broke the stuff up. So maybe the same thing would happen in the water/alcohol mixture used in the meth synth, the water allowing the P2P to break away from whatever it's bonding to.)

Alternatively, I was thinking that the P2P might be extracted from the stuff before distillation, as a bisulfite adduct, as mentioned here: https://www.rhodium.ws/chemistry/p2p.phenylacetic.html

Chemical separations were conducted by means of a bisulfite addition complex and Girard's reagent T. The aqueous sodium bisulfate extraction of the reaction mixtures removed most of the P2P present; however, higher ketones do not produce bisulfite adducts as easily because of the sensitivity of the additions to steric hindrance⁴⁵. The water-soluble bisulfite-P2P addition product may be hydrolyzed with strong acid or base to regenerate P2P for examination. The nonbisulfite retained compounds were reacted with Girard's reagent T, a material known to react with ketones to also form water-soluble adducts, which allows separation of ketonic and nonketonic compounds. An organic extraction allowed clean isolation of all nonketonic compounds into an organic phase.

That Girard's reagent T stuff sounds promising, as well, heh... though it sounds like it's really not needed for P2P, and that a sodium bisulfate extraction would work... though, again, if the P2P is already tied up in some sort of complex, I'm not sure whether it would react to form the bisulfite adduct...

*sigh*. SWIM plans next time to just take the viscous liquid left after removing the toluene & toss it in to the Al/Hg/Nitro synth. Maybe this is all much ado about nothing.

p.s. Please forgive my (undoubtedly) awkward way of describing my questions / problems / ideas about this stuff. I'm well aware that I don't know squat about chemistry compared to a lot of people here, and so am not sure when whatever ideas I'm trying to express might be either ridiculous errors in understanding, or painfully obvious restatements of already well-known concepts that everyone else, as a matter of course, takes as a 'given'. But I do my best to work things out using what little I do know, and what I'm able to gather from the research & ruminations of other bees who appear to know what they're talking about a lot more often than I do. So thanks for all the help, peoples, and please bear with me.

knowing is the easy part

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