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Thread: Schiff's bases

  1. #121

    Default Re: Schiff's bases

    I only ever tried making Indolene (Indole plus Hydroxycitronellal), so cannot answer your question Justin. I still don't know if what I made was Indolene, it certainly didn't smell the same as the commercial stuff we used which was much more floral, and less Indolic. I'm sure the HCA made a contribution, but I'm also sure that there was less free Indole in the commercial stuff.

  2. #122
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    Default Re: Schiff's bases

    Quote Originally Posted by David Ruskin View Post
    I only ever tried making Indolene (Indole plus Hydroxycitronellal), so cannot answer your question Justin. I still don't know if what I made was Indolene, it certainly didn't smell the same as the commercial stuff we used which was much more floral, and less Indolic. I'm sure the HCA made a contribution, but I'm also sure that there was less free Indole in the commercial stuff.
    Thanks David, I'll try a few more with indole and see if they are similar, I'll also try heating them for longer to see if the color changes to brown eventually.
    Justin E. Beasley

  3. #123

    Default Re: Schiff's bases

    Quote Originally Posted by David Ruskin View Post
    How do you filter out Magnesium Sulphate (anhydrous I assume) from a reacted Schiff's Base that is as thick as treacle?
    david,

    there are a number of ways to filter this, you could remove MgSO4 from a product that would be crystalline, but as you have
    mentioned these types of reactions would go beyond most DIY'ers.

  4. #124

    Default Re: Schiff's bases

    Quote Originally Posted by JEBeasley View Post
    Thanks David, I'll try a few more with indole and see if they are similar, I'll also try heating them for longer to see if the color changes to brown eventually.
    justin,

    for what it's worth, if you search for some of these reactions, most use high temps, 80C to 120C, under vacuum, so
    your at a very high temp without a vacuum, they hold that temp during the reaction times of many hours, in some cases 8 or more hours.

  5. #125

    Default Re: Schiff's bases

    At these temperatures, won't the water evaporate if you open the bottle once in a while (and if working on small quantities)?

  6. #126
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    Default Re: Schiff's bases

    The Indole + hydroxycitrollal combo from yesterday has been on the hot plate for over an hour and it is turning dark brown. The "moth-ball" edge is smoothing out a little although it's still far too indole smelling and definitely moreso than Indolene 50 but it seems like a good sign that it's smoothing out and turning brown. I don't expect it to become Indolene 50, as David said it's more complicated than just heating it like the others but I am interested in seeing what happens to the color and odor as it continues to heat.

    The bases that came off cloudy were re-heated, more water vapor was evaporated, condensation formed inside the vial so I swabbed the condensation from the inside of the 1 dram vial with a 6" cotton swab and let them cool. They are no longer cloudy. Helional took the longest to clarify and Lilial was the second longest to clarify.

    I remade the C-11 and diluted with alcohol only this time, it turned out perfectly, no clouding no solubility problems. I suspect that the first vial of C-11, that is cloudy, might have one of three problems:
    1. The C-11 Schiff base is not entirely soluble in DPG
    2. I overcooked the first C-11 schiff base and it is partially solidified and not entirely soluble in alcohol or DPG (most likely the case)
    3. My DPG is of poor quality or somehow contains water

    I'm making a third C-11 schiff base according to the same specifications as the second in terms of time, heat, color and clarity and then I will dilute with DPG + alcohol to compare. If it is cloudy once again then I will assume my DPG is bad because David says that the C-11 base is soluble in DPG, if it is clear then it will tell me that I overcooked the first sample and everything else is fine (although this still doesn't settle the mystery as to why some of my absolutes are cloudy when using DPG + Ethyl Alc...).
    Justin E. Beasley

  7. #127
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    Default Re: Schiff's bases

    Quote Originally Posted by luigi_g View Post
    justin,

    for what it's worth, if you search for some of these reactions, most use high temps, 80C to 120C, under vacuum, so
    your at a very high temp without a vacuum, they hold that temp during the reaction times of many hours, in some cases 8 or more hours.
    Yikes! So, are you saying to keep it at around 50C for up to 8 hours?
    Justin E. Beasley

  8. #128
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    Default Re: Schiff's bases

    Quote Originally Posted by Nizan View Post
    At these temperatures, won't the water evaporate if you open the bottle once in a while (and if working on small quantities)?
    I'm keeping my new bases at between 50-60C, I do get condensation in the vial and there is some evaporation out of the vial but as David pointed out, if the base is cloudy then it contains water. I re-heated the cloudy ones for up to another 30 minutes, the vials formed condensation again. I took them off the hot plate and allowed them to cool. If they were still cloudy then I put them back on the hot plate, if not, then I swabbed the water off the inside of the vial. I did this with my second C-11 base and it came out very clear after dilution.
    Justin E. Beasley

  9. #129

    Default Re: Schiff's bases

    Quote Originally Posted by Nizan View Post
    At these temperatures, won't the water evaporate if you open the bottle once in a while (and if working on small quantities)?
    yes, Nizan, that is one of the reasons for the vacuum and high temps, the water MUST be removed during the reaction
    lets say it is ran at near 28 inches of vacuum,, doable with a home vacuum pump, so that is around 49-50 torr
    water boils at 40C, so an 80C reaction temp is double the boiling point of the water,

  10. #130

    Default Re: Schiff's bases

    justin,

    check this link out
    http://www.freepatentsonline.com/4840801.html

    it lists a number of aldehye reactions with MA

    here is the reaction of MA and Bergamal

    Preparation of Schiff Base of Methyl Anthranilate and Bergamal

    Into a 2 liter, 3 neck reaction flask equipped with stirrer, thermometer, glass "Y" adapter, 1 liter addition funnel, steam distillation head with a 45/50 bottom male joint attached to the reaction flask, head thermometer, curved fraction cutter with a 50 ml receiver, heating mantle controlled with a "Therm-O-Watch", dry ice trap, Bennert Manometer, vacuum bleed valve and vacuum pump is placed 302.0 grams of methyl anthranilate having the structure: ##STR148##

    With stirring using the 1 liter addition funnel, 332.0 grams of Bergamal having the structure: ##STR149## is added dropwise to the reaction mass over a one hour period while slowly heating the reaction mass to 50° C.

    The 1 liter addition funnel is then removed from the reaction flask and vacuum (50.0 mm/Hg.) is applied to the system.

    With stirring, the reaction mass is gradually heated to 100° C. over a 45 minute period.

    Heating is continued at 100° C. for a period of eight hours while removing water at a vapor temperature of 35°-45° C.

    The reaction flask is then cooled to 50° C.

    The resulting product has an intense lemony and floral aroma.

  11. #131
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    Default Re: Schiff's bases

    Quote Originally Posted by luigi_g View Post
    yes, Nizan, that is one of the reasons for the vacuum and high temps, the water MUST be removed during the reaction
    lets say it is ran at near 28 inches of vacuum,, doable with a home vacuum pump, so that is around 49-50 torr
    water boils at 40C, so an 80C reaction temp is double the boiling point of the water,
    What kind of vacuum pumps are available for this kind of work in a home work space?
    Justin E. Beasley

  12. #132
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    Default Re: Schiff's bases

    Quote Originally Posted by luigi_g View Post
    justin,

    check this link out
    http://www.freepatentsonline.com/4840801.html

    it lists a number of aldehye reactions with MA

    here is the reaction of MA and Bergamal

    Preparation of Schiff Base of Methyl Anthranilate and Bergamal

    Into a 2 liter, 3 neck reaction flask equipped with stirrer, thermometer, glass "Y" adapter, 1 liter addition funnel, steam distillation head with a 45/50 bottom male joint attached to the reaction flask, head thermometer, curved fraction cutter with a 50 ml receiver, heating mantle controlled with a "Therm-O-Watch", dry ice trap, Bennert Manometer, vacuum bleed valve and vacuum pump is placed 302.0 grams of methyl anthranilate having the structure: ##STR148##

    With stirring using the 1 liter addition funnel, 332.0 grams of Bergamal having the structure: ##STR149## is added dropwise to the reaction mass over a one hour period while slowly heating the reaction mass to 50° C.

    The 1 liter addition funnel is then removed from the reaction flask and vacuum (50.0 mm/Hg.) is applied to the system.

    With stirring, the reaction mass is gradually heated to 100° C. over a 45 minute period.

    Heating is continued at 100° C. for a period of eight hours while removing water at a vapor temperature of 35°-45° C.

    The reaction flask is then cooled to 50° C.

    The resulting product has an intense lemony and floral aroma.
    Interesting! So, can this be done at home? What is the point of dropping it in over a one hour period? Since I'm working at micro scale and seem to be able to swab out water as condensation then should I just heat continuously for 1.75 hours @ 50C without a vacuum?
    Justin E. Beasley

  13. #133

    Default Re: Schiff's bases

    Quote Originally Posted by JEBeasley View Post
    What kind of vacuum pumps are available for this kind of work in a home work space?
    i use one like this
    http://www.ebay.com/itm/2Stage-Deep-...-/390197834672

  14. #134
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    Default Re: Schiff's bases

    Quote Originally Posted by luigi_g View Post
    Nice, not a bad price either. What sort of setup is required to attach the vacuum to the top of the vessel containing the aldehyde and base?
    Justin E. Beasley

  15. #135

    Default Re: Schiff's bases

    Quote Originally Posted by JEBeasley View Post
    Interesting! So, can this be done at home? What is the point of dropping it in over a one hour period? Since I'm working at micro scale and seem to be able to swab out water as condensation then should I just heat continuously for 1.75 hours @ 50C without a vacuum?
    dropping the temp slowing will insure that all of the water is removed.

    don't think i know the answer to your second question, given what apparatus you have...
    certainly you could try/test that....

    since you mentioned you see the water, do you have any pH strips, if so could you try to test the pH?

  16. #136

    Default Re: Schiff's bases

    Quote Originally Posted by JEBeasley View Post
    Nice, not a bad price either. What sort of setup is required to attach the vacuum to the top of the vessel containing the aldehyde and base?
    oh, i just use a erlenmeyer vacuum flask;
    the large ones 1L - 2L for vacuum filtering
    or small ones like this one for small reactions
    http://www.ebay.com/itm/Corning-PYRE...item4d144fc800

    make sure you buy the heavy wall, a small tap, bump under vacuum will cause these to fracture

  17. #137
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    Default Re: Schiff's bases

    Quote Originally Posted by luigi_g View Post
    dropping the temp slowing will insure that all of the water is removed.

    don't think i know the answer to your second question, given what apparatus you have...
    certainly you could try/test that....

    since you mentioned you see the water, do you have any pH strips, if so could you try to test the pH?
    No, I was wondering what is the point of dripping the aldehyde into the MA over an hours period of time?

    I do have some PH strips around somewhere but I have to find them. I have a PH meter too but that won't help as the condensation is too little.
    Justin E. Beasley

  18. #138

    Default Re: Schiff's bases

    This is why i mention Vaccum ... the aldehydes will preserve quality, but im not sure if the shiff base reaction will be better/faster reducing atomspheric pressure.

    Lets test it

    IMG_4616 (Andere).JPG

    A lil hole do get vacuum inside
    IMG_4621 (Andere).JPG

    final construction
    IMG_4628 (Andere).JPG

  19. #139

    Default Re: Schiff's bases

    Quote Originally Posted by JEBeasley View Post
    No, I was wondering what is the point of dripping the aldehyde into the MA over an hours period of time?

    I do have some PH strips around somewhere but I have to find them. I have a PH meter too but that won't help as the condensation is too little.
    oh sorry justin,

    my vison is all but gone due to MS, so many times, i don't read / see things right.....

    so titrating in the aldehyde ensures the leaving group / water can be removed as it forms....
    these reactions are what are called reversible reactions, so if the water remains in the mixture, and if there is the slightest
    amount of an acid level, the products turn back into the reactants, or form un wanted side reactions,
    maybe not in your case but in general

    also some aldehydes are to sensitive to high heat, so added them in slowly will get that small amount to form the intermediate product which is much more stable to high heat, then when all of the aldehyde has gone thru the first reaction phase, then the higher heat can be used to drive the reaction to completion, which causes the water to form as one of the products...and the schiff base to form
    Last edited by luigi_g; 12th February 2014 at 09:52 PM.

  20. #140

    Default Re: Schiff's bases

    Quote Originally Posted by bigbang View Post
    This is why i mention Vaccum ... the aldehydes will preserve quality, but im not sure if the shiff base reaction will be better/faster reducing atomspheric pressure.

    the vacuum is used only to lower the temps and get the water out of the reaction vessel

    nice setup btw!!
    Last edited by luigi_g; 12th February 2014 at 09:59 PM.

  21. #141
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    Default Re: Schiff's bases

    I found my PH strips but they are old so hopefully they still work.
    I tested two different vials but I had to re-heat them as the bases were sufficiently clear - I already swabbed all of the vials out. From the tiny drips I was able to capture it looks as though one sample tested around 4.5 and the other around 5.0 so they both have acidic condensation. I'll test a few more later but I have to go pick up my daughter from school, it will take me a couple of hours to get back to this most likely.
    Justin E. Beasley

  22. #142
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    Default Re: Schiff's bases

    I tested the PH papers with my PH meter calibration solutions (7.0 & 4.0) and they are still accurate.
    Justin E. Beasley

  23. #143
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    Default Re: Schiff's bases

    Is there anything I'm missing? Are there any other aroma chems, besides aldehydes and ketones, that react with Methyl Anthranilate to form ANY kind of base?

    EDIT: From the linked patent paper luigi_g posted I found out that Melonal and Floralozone can be made into a schiff base as well, WOHOO!

    EDIT2: I just read that the ionones, hedione and damascones are considered "rose ketones" are these also candidates for schiff bases? What about Iso E Super? According to wikipedia it's a "synthetic ketone"...
    Last edited by JEBeasley; 13th February 2014 at 07:59 PM.
    Justin E. Beasley

  24. #144

    Default Re: Schiff's bases

    Seems like there's no escaping learning some organic chemistry
    I'm still struggling with MA and benzaldehyde.. They just won't form a basis, even though there seem to be a lot of water evaporating from the mix (I think it should lose around 6% its weight to water, but there's no way of telling what has evaporated)..
    And I know there's no base created since after a couple of hours it still smells like MA on the strip..

  25. #145

    Default Re: Schiff's bases

    Quote Originally Posted by Nizan View Post
    Seems like there's no escaping learning some organic chemistry
    I'm still struggling with MA and benzaldehyde.. They just won't form a basis, even though there seem to be a lot of water evaporating from the mix (I think it should lose around 6% its weight to water, but there's no way of telling what has evaporated)..
    And I know there's no base created since after a couple of hours it still smells like MA on the strip..
    you should lose exactly 18.01528 gr of water per the 1:1 mole ratio
    so if you used say 10% of a mole of each, you should lose exactly 1.801528 grams of water

  26. #146
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    Default Re: Schiff's bases

    Quote Originally Posted by Nizan View Post
    Seems like there's no escaping learning some organic chemistry
    I'm still struggling with MA and benzaldehyde.. They just won't form a basis, even though there seem to be a lot of water evaporating from the mix (I think it should lose around 6% its weight to water, but there's no way of telling what has evaporated)..
    And I know there's no base created since after a couple of hours it still smells like MA on the strip..
    If you have a mg scale you can weigh the solution prior to heating it and then every so often to see how much water is dissipating.

    Everything I've done so far changes color, some change faster than others and some colors are darker and richer but most of them range from light yellow to orange with a couple brown and one brown-black. I found one source online stating that ketones need to be heated at higher temps for longer and I found this to be true prior to finding this source. Most of my aldehydes showed color change and condensation after 15-20 minutes and seem complete after 30 min, a few took an hour or more, the ketones usually took one to two hours at higher temps. A couple aldehyde bases I remade because I cooked them too long and they had non-dissolving solids in dilution. A couple were cloudy after they cooled indicating water content so I put them back on the burner for fifteen to twenty minutes. Helional took longer than most of the other ketones to clarify.

    The indolene 50 experiment I tried eventually turned dark, somewhat opaque, brown and mellowed out, it smelled like it was blended with castoreum oddly enough and finally gave up the hydroxy citronellal note but it's not as deep, sweet and floral as what I purchase and the indolene 50 from PA is more transparent and stays glossy on paper for half a day. I gave up on the indole experiment after eight hours of continuous heating 50-60C.

    I still have to finish making a few ketones, dilute and test on strips so we'll see how it goes. If all goes well I should be done by this weekend.
    Last edited by JEBeasley; 14th February 2014 at 04:21 AM.
    Justin E. Beasley

  27. #147

    Default Re: Schiff's bases

    It has been heating for hours.. It did change color, but isn't very thick.. But for some reason it just smells like MA on the dry out..

  28. #148

    Default Re: Schiff's bases

    It has been heating for hours.. It did change color, but isn't very thick.. But for some reason it just smells like MA on the dry out.. Did you check the bases you made with more volatile aldehydes? Do they still smell different from MA after a couple of hours?

  29. #149

    Default Re: Schiff's bases

    Looks like you guys have things well in hand.

    Just dropped by to double facepalm and say ignore/forget nearly everything I said about indole; I forgot the aromaticity means it does not react like a typical secondary amine and does not form enamines with aldehydes/ketones. It generally reacts with them at carbon #3, not the nitrogen. I went back and crossed out all my references to it acting like a base that I could find. If I missed some feel free to drop me a message.

    I'm happy to see the thread bubbling away. Carry on.

  30. #150

    Default Re: Schiff's bases

    What are the practical implications of this?

  31. #151

    Default Re: Schiff's bases

    They'll still react, just differently than I had been thinking. See pages 39-40. luigi_g already touched on this in passing.

    Practically? It's acid-catalyzed and readily-available HCl would probably speed things up, but then you'd have to neutralize it afterwards and lose product cleaning it, plus account for the water that was added with the HCl, so driving off the water with heat is still the most user-friendly idea if the reaction will go under those conditions. I just didn't want to leave my errors sitting there without saying anything.

  32. #152
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    Default Re: Schiff's bases

    Quote Originally Posted by Nizan View Post
    It has been heating for hours.. It did change color, but isn't very thick.. But for some reason it just smells like MA on the dry out.. Did you check the bases you made with more volatile aldehydes? Do they still smell different from MA after a couple of hours?
    I have checked a few and they are considerably more stable on a smelling strip. I've even made a base from a normally top note volatile ketone and it outlasts the original 8 hour ketone by at least 24 hours. Not all of mine changed consistency, most of them are extremely thick but a few are still pretty thin even though they are bright orange or yellow. I'm not sure why yours would still smell of methyl anthranilate... perhaps that's how that base is supposed to smell. Is it possible you used too much MA in your formulation? Are your temps stable betweeen 50-60C? When you let it cool completely is it cloudy or clear?
    Last edited by JEBeasley; 14th February 2014 at 06:17 AM.
    Justin E. Beasley

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    Default Re: Schiff's bases

    Quote Originally Posted by JayH View Post
    They'll still react, just differently than I had been thinking. See pages 39-40. luigi_g already touched on this in passing.

    Practically? It's acid-catalyzed and readily-available HCl would probably speed things up, but then you'd have to neutralize it afterwards and lose product cleaning it, plus account for the water that was added with the HCl, so driving off the water with heat is still the most user-friendly idea if the reaction will go under those conditions. I just didn't want to leave my errors sitting there without saying anything.
    This is what I've read, that all of these aldehyde/ketone reactions can be catalyzed with strong acids but heat works fine accept that it takes longer.

    Nizan, mabe the benzaldehyde just takes an incredibly long amount of time. That indole I tried took over eight hours for considerable change to occur. I heated C14, C16 & C18, while I know they are not true aldehydes, they did change color and form condensation in the vial but it took around 3-4 hours and higher temps similar to the ketones. I still don't know if they are truly bases but they act like it on a smelling strip and that's all I care about.
    Justin E. Beasley

  34. #154

    Default Re: Schiff's bases

    Quote Originally Posted by JayH View Post
    Looks like you guys have things well in hand.

    Just dropped by to double facepalm and say ignore/forget nearly everything I said about indole; I forgot the aromaticity means it does not react like a typical secondary amine and does not form enamines with aldehydes/ketones. It generally reacts with them at carbon #3, not the nitrogen. I went back and crossed out all my references to it acting like a base that I could find. If I missed some feel free to drop me a message.

    I'm happy to see the thread bubbling away. Carry on.
    Now I wonder who else it was who doubted the use of Indole in this sort of experiment? Comforting to know of others' happiness though.

  35. #155

    Default Re: Schiff's bases

    Quote Originally Posted by JEBeasley View Post
    This is what I've read, that all of these aldehyde/ketone reactions can be catalyzed with strong acids but heat works fine accept that it takes longer.

    Nizan, mabe the benzaldehyde just takes an incredibly long amount of time. That indole I tried took over eight hours for considerable change to occur. I heated C14, C16 & C18, while I know they are not true aldehydes, they did change color and form condensation in the vial but it took around 3-4 hours and higher temps similar to the ketones. I still don't know if they are truly bases but they act like it on a smelling strip and that's all I care about.
    This whole buisness is pretty frustrating.. My whole apartment smells like almonds (which is nice) because I'm leaving the vial open too allow water to evaporate.. That way I know there's still benzaldehyde there.. The base is supposed to be solid which a boiling point of 400 C - and I definitely don't have that.. Though it is thickening, and still very clear. And I have no way to check the temperature yet.. What does 50 C feel like on the finger? And how about 70?

    Update - how do I know the condensation in the bottle is water and not something else? It smells of the whole mixture..
    Last edited by Nizan; 14th February 2014 at 01:00 PM.

  36. #156

    Default Re: Schiff's bases

    Quote Originally Posted by David Ruskin View Post
    Now I wonder who else it was who doubted the use of Indole in this sort of experiment? Comforting to know of others' happiness though.
    EDIT: No, never mind. I'm not engaging you.

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    Default Re: Schiff's bases

    Quote Originally Posted by Nizan View Post
    This whole buisness is pretty frustrating.. My whole apartment smells like almonds (which is nice) because I'm leaving the vial open too allow water to evaporate.. That way I know there's still benzaldehyde there.. The base is supposed to be solid which a boiling point of 400 C - and I definitely don't have that.. Though it is thickening, and still very clear. And I have no way to check the temperature yet.. What does 50 C feel like on the finger? And how about 70?

    Update - how do I know the condensation in the bottle is water and not something else? It smells of the whole mixture..
    If you have a meat thermometer you can place it in your water bath to determine the temps. Otherwise I'm not sure how to tell you to get that part right without a temp gauge or thermostat or something to regulate. Temps can vary and different conditions can increase or decrease your temps but you know that. I had a fan in the window exhausting heat and aroma out the window. My regulator was set at 60 with the temperature probe in a water bath, the temps would fluctuate due to the room being cold but they consistently stayed in the range of 52-56 most of the time, so, a little higher than the 50C that has been suggested here. If I stick my finger in 50C water I can only keep it there for a second or two before it becomes very unfomfortable, it's going to be too hot for a hot-tub. At 70C I won't stick my finger in it but the water is not yet boiling.

    Try this: Bring the water exactly up to the point of boiling (100C) - no more, look at where the thermostat is and turn it down half the distance of the regulator knob position to off, let the water come down to temp - assuming you are using a hot plate and the potentiometer temp control doesn't matter (linear or logarithmic potentiometer) I might be wrong in assuming that a hot plate potentiometer is a logarithmic taper...

    The first ones I made I really cooked the hell out of them so don't worry too much about it being perfect, if you cook one too long then start over and reduce the temp a little until you get it right. The first Cinnamic Aldehyde I made at 70C and cooked for far too long. David was right about it being a poor quality material as there are undissolved solids in the diluted bottle that don't dissolve into an alcoholic solution with heat either. It also has less tenacity on a strip compared to the second cinnamic aldehyde I made @ 50-60C for 30min (Although, the first cinnamic aldehyde is a little different and no less interesting). There were four more I cooked at the same higher temp as the cin ald. - C11, hyxyl Cin. Ald., Anisic Ald. & Methyl Cedryl Ketone. The only other one that did not fare well at the higher temp for a longer time is the C11 - it's dark brown and has solubility issues (I remade it). The rest turned out fine and in fact seemed to require higher temps to get them there. It seems to me from your comments that benzaldehyde might need more extreme treatment. Even amongst the ketones, which normally require higher temps for longer, there were a couple that reacted very quickly and finished in the same time as a typical aldehyde (Beta Damascone) so there is not a single correct temp and time for all AC's of any given type, just "typical" heat and times for most of a given type (aldehyde/ketone). Also, they are not all thick as honey, some are considerably thinner but more thick than the original materials and not until they cool down to room temps.

    The water condensation has all of the properties of water but you are right in that I don't actually know if it's water or not but I can say that it contains water because I can test it's PH with PH paper (PH 4.5-5.0). When I swab the "water" out of the vial the swab smells of the material, it does not smear or feel sticky and evaporates like water off of the swab, the consistency is that of water. I don't know what other clear liquid would condense on the inside of the bottle with all of the properties of water and not be water...
    Last edited by JEBeasley; 14th February 2014 at 05:34 PM.
    Justin E. Beasley

  38. #158

    Default Re: Schiff's bases

    Quote Originally Posted by JayH View Post
    They'll still react, just differently than I had been thinking. See pages 39-40. luigi_g already touched on this in passing.

    Practically? It's acid-catalyzed and readily-available HCl would probably speed things up, but then you'd have to neutralize it afterwards and lose product cleaning it, plus account for the water that was added with the HCl, so driving off the water with heat is still the most user-friendly idea if the reaction will go under those conditions. I just didn't want to leave my errors sitting there without saying anything.
    jayH,

    you can't use HCL, when the carbonyl O accepts the H+ from the HCL, you have a free CL ion, way to reactive
    you need to use H2SO4, that would also make H2SO4 as the leaving group, so H2O is only an intermediate
    so you would only need to remove the acid from the product as you mentioned.

  39. #159
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    Default Re: Schiff's bases

    I'm ready to move onto the next step - testing all of them on smelling strips, side by side, with their mother AC to see how they differ and see if there is any hint of MA left in product. Is it customary to test them neat before diluting? Should I dulute them prior to testing? Oranger crystals, Raspberry ketone and Ethyl Vanillin are crystals so I don't think that it's possible to test without diluting first.

    I have 35 different materials that I experimented with but I'll exclude the one indole experiment so there are 34. Probably half of them are no doubt legit because they clearly have the word "aldehyde" or "ketone" in the name of the AC. The rest are AC's that I found reference to being made into bases in patents or from web sites referring to them as ketones (ex. "Rose Ketones": damascones, ionones & hedione). Some are questionable in terms of whether or not they are definitely bases but I don't know how to rule them out because they changed color, changed viscosity and seem to act like bases on a smelling strip so, even if they aren't traditional bases they act like one as far as I can tell. That said, for some of the more difficult ones that showed no change at normal temps of 50-60C (color, condensation, viscosity, etc) I raised the temp and left them on the burner for longer until they showed some change and they all had the aforementioned changes (color, condensation, viscosity, etc) eventually - Some were heated for up to four hours @ 50C and some up to three hours at 70C. Every AC was different in terms of how dramatic and how fast the changes occured. I have already ruled out my innitial attempts that were clearly flawed and exhibited signs such as poor solubility and poor odor strength along with extremely dark coloration - These were all re-made and are included in the list. If any were cloudy after cooling then I put them back on the hot plate for another 15-20 minutes. After each base had cooled completely I swabbed out the condensation from the upper half of the vial with a 6" cotton swab.

    Through this evaluation process I fully expect that some will be eliminated as forgeries so it will be very interesting to see what is left over. I'm also not ruling out the possibility that I will be fooled by a few but I will post about that so that anyone willing to join in can try to replicate and give their opinion as well.

    For anyone wishing to repeat any part of this experiment please keep in mind that my samples were all in the micro range of .250g - .400g beginning weight in a 1 dram dropper bottle - DROPPER REMOVED - vial tops open (three experiments were made in larger amounts 3-4g ea with the same results as micro amounts). The aroma chemicals were heated in the dropper bottles. This will make a difference considering how much material you are heating, if you are heating a considerable amount of material you might not get good evaporation and vacuum may be required to complete the process. Please be sure to ventilate your work space sufficiently and be attentive.

    Following the materials list there is the list of potential aldehyde and ketone bases made with Methyl Anthranilate: Please let me know if there are any on the following list that are definitely NOT reactive with MA (neither an Aldehyde nor a Ketone and do not hold the capability to react) and I will test them with extreme prejudice.

    Materials used:
    Digital temp controlled hot plate
    1 dram glass vials (dropper tops removed)
    500ml borosilicate glass beaker (water bath)
    Water
    mg scale
    6" cotton swabs (hobby or medical supply)
    Ventilation fan + window
    Paper towels
    Watchful eye - Don't let your water bath evaporate completely below the temp probe, keep your temp probe touching the bottom of the vessel as a safeguard.
    Paper strips for evaluation
    Methyl Anthranilate

    Aldehydes
    1. Cyclamen Aldehyde
    2. Hydroxycitronellal
    3. Citronellal
    4. Helional
    5. Triplal
    6. C-8
    7. C-10
    8. C-11
    9. C-12 Lauric
    10. C-12 MNA
    11. Phenyl Acetaldehyde
    12. PADMA
    13. Hexyl Cinnamaldehyde
    14. C-14
    15. C-16
    16. C-18
    17. Ethyl Vanillin
    18. Floralozone
    19. Cinnamic Aldehyde
    20. Anisic Aldehyde
    21. Mandarine Aldehyde
    22. Lilial

    Ketones
    23. Methyl Cedryl Ketone
    24. Raspberry Ketone
    25. Methyl Hexyl Ketone
    26. Oranger Crystals
    27. Iso E Super
    28. Dihydro Ionone Beta
    29. Ionone Alpha
    30. Damascone Beta
    31. Jasmone Cis
    32. Nectaryl
    33. Melonal
    34. Hedione

    There are a few I have that I did not experiment with, they will be for a later date (Namely, Ionone Beta, Delta Damascone, etc)
    Last edited by JEBeasley; 14th February 2014 at 08:01 PM.
    Justin E. Beasley

  40. #160

    Default Re: Schiff's bases

    And we are back to the size of our retorts. I give up. I will not be participating in this thread any more.

  41. #161

    Default Re: Schiff's bases

    Quote Originally Posted by luigi_g View Post
    jayH,

    you can't use HCL, when the carbonyl O accepts the H+ from the HCL, you have a free CL ion, way to reactive
    you need to use H2SO4, that would also make H2SO4 as the leaving group, so H2O is only an intermediate
    so you would only need to remove the acid from the product as you mentioned.
    You are almost certainly correct. I found a couple references [x] [x] to using HCl as the catalyst, but it doesn't seem to be generally practiced. H2SO4 looks much more promising. Phosphoric acid also came up, interestingly enough.

    This mentions using lemon juice. Potentially very DIY friendly if you have an ultrasonic cleaner.

  42. #162

    Default Re: Schiff's bases

    Quote Originally Posted by JayH View Post
    You are almost certainly correct. I found a couple references [x] [x] to using HCl as the catalyst, but it doesn't seem to be generally practiced. H2SO4 looks much more promising. Phosphoric acid also came up, interestingly enough.

    This mentions using lemon juice. Potentially very DIY friendly if you have an ultrasonic cleaner.
    great find, my ultrasonic goes up to 80'C

    edit ...
    jayH, this is just brilliant, check out the structure of citric acid, it is perfect for this
    Last edited by luigi_g; 14th February 2014 at 08:26 PM.

  43. #163
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    Default Re: Schiff's bases

    Quote Originally Posted by JayH View Post
    You are almost certainly correct. I found a couple references [x] [x] to using HCl as the catalyst, but it doesn't seem to be generally practiced. H2SO4 looks much more promising. Phosphoric acid also came up, interestingly enough.

    This mentions using lemon juice. Potentially very DIY friendly if you have an ultrasonic cleaner.
    My ultrasonic only gets up to 65 but lemon juice seems like a great option! How does one go about removing the lemonjuice after the fact though? The water will evaporate but all of the lemon flavor will still be in there. What about white vinegar?
    Justin E. Beasley

  44. #164

    Default Re: Schiff's bases

    Lemon flavor isn't a bonus?

    Okay, I kid, I kid.

    Vinegar should work. I think typical household vinegar is close to the same pH as lemon juice, though they both vary. You're right the citric acid might be complicated to remove, though I like its status as one of few chemicals outright embraced by the "naturals" crowd. The acetic acid in the vinegar should evaporate out even before the water does...something to keep in mind but it's a possibility for removal and it doesn't look like this reaction necessarily needs to be dry. The chemists in the link were reporting good yields with water deliberately included, and I don't think it's as easily reversible as the formation of a Schiff base.

    Look up bis-indolyl methanes. Apparently there's a lot of work being done on this for one reason or another.

    EDIT: Actually, the first page of the link mentions acetic acid being used. Maybe it will benefit from ultrasound as well.

  45. #165

    Default Re: Schiff's bases

    Justin - that's pretty awesome! Can't wait to hear your insights!
    I kept warming the base I was trying to make.. There's still condensation going on, and
    it thickened a bit.. Now sure at what stage to stop and test it out..

  46. #166
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    Default Re: Schiff's bases

    Quote Originally Posted by Nizan View Post
    Justin - that's pretty awesome! Can't wait to hear your insights!
    I kept warming the base I was trying to make.. There's still condensation going on, and
    it thickened a bit.. Now sure at what stage to stop and test it out..
    I was unsure about that too and I still am for the most part but usually what I did was keep watching, assessing, smelling... I had to make a few big mistakes in order have a feel for what I was looking at and what to look for. When I made the C11 and cinnamic aldehyde for the first time I obviously overheated them and it showed because they were too thick, too dark and weren't easily soluble in alcohol. The smell was different too, the C11 was more musty and phenolic, not bad per se but different. The cinnamic aldehyde was hard like tar, didn't dissolve readily and was weak on a smelling strip. When I remade those two I made sure to take them off of the heat once the color became bright and rich, the condensation seemed to slow down or remained the same and they had become a bit thicker in consistency - most of the aldehydes seemed finished around the 30 minute mark except for C14, C16 & C18 which may or may not even be bases at all.

    After that initial overcooking experience I watched each vial as I put it on the hot plate for the first time. As soon as I noticed condensation and color change I would check on it every ten minutes to see how fast it was changing color and pay attention to the amount of condensation in the vial. If the color and condensation came on fast then it seemed like the reactions were happening fast and I made the assumption that it didn't need to be heated for as long as some others. After about 15-30 minutes I would pick up the vial and check for consistency and give it a quick whiff. Once the color became very bright and rich and it smelled more homogenized and clear (very little trace of MA) and the thickness had changed then I would watch it for another ten and then take it off of the heat. After a couple hours of cooling some of them were cloudy, those got put back on the hot plate for another 15-20 minutes.

    There were a few exceptions to my methodology, helional needed more time even though it seemed finished but after it cooled it was still cloudy... twice, third time was a charm as they say. The other curious one was beta damascone, even though it's described as a rose ketone it turned a brilliant shade of pink-orange (salmon?) pretty quickly and just kept getting richer. In evaluating the smell of it it didn't seem finished even though the color came on strong, I let it heat for longer based on it's smell mostly as the MA seemed as though it were still too present.

    So, really, my methods are pretty unorthodox and more based on an intuitive sense about how fast the reactions SEEM to be happening but I don't really know for sure, I'll see how they turned out. I wasn't able to record every aspect of every base I made but I figure this won't be my last base making excursion so next time I make each base I'll write down more specific heating times, temps, color changes, ratios, etc and really hone in on minor details. For this run it was more about getting my feet wet, figuring out the process and assessing how worth while it is to make these bases.

    If my weekend goes the same way as the past two days then I'm not sure I will get back to it until next week. For whatever reason everything that could have gone wrong yesterday happened so I'm now in a game of catching up with neglected household chores and necessities in addition to cleaning up after an all night puke fest because my daughter was up sick all night.
    Last edited by JEBeasley; 15th February 2014 at 09:10 PM.
    Justin E. Beasley

  47. #167

    Default Re: Schiff's bases

    Tuesday, I made the Phenylacetaldehyde MA schiff base, simply by adding the appropriate amounts of the material, shook it up, and put it on the shelf for two days. This Morning, it is bright yellow fluid, It's a little thick (clouded), it has a small air bubble slowly rising in the soup, can't see any stratification of water, smells nice, strong, seems like it just worked itself out very nicely with simple prep.

    YAY!

    Try it out!

    PK
    Paul Kiler
    PK Perfumes
    http://www.PKPERFUMES.com
    Gold Medal for "Best Aroma"; Los Angeles Artisan Fragrance Salon

  48. #168

    Default Re: Schiff's bases

    Quote Originally Posted by JayH View Post
    Looks like you guys have things well in hand.

    Just dropped by to double facepalm and say ignore/forget nearly everything I said about indole; I forgot the aromaticity means it does not react like a typical secondary amine and does not form enamines with aldehydes/ketones. It generally reacts with them at carbon #3, not the nitrogen. I went back and crossed out all my references to it acting like a base that I could find. If I missed some feel free to drop me a message.

    I'm happy to see the thread bubbling away. Carry on.
    I’m afraid the detailed chemistry is a bit beyond me, but I do know with some certainty that indole and hydroxycitronellal can be reacted together to form a condensation product usually referred to in the perfumery trade as a Schiff’s Base, though perhaps not correctly, and generally known as indolene.
    A person who is nice to you, but rude to the waiter, is not a nice person.”
    ― Dave Barry

    Chris Bartlett
    Perfumes from the edge . . .

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    If you are looking for a perfumery consultation I’m happy to quote: if you want free advice, that’s what these forums are for
    You can also join my blog if you wish to ask questions of me.

  49. #169

    Default Re: Schiff's bases

    Paul - so what's your impression? Together with some Clary it reminds me of Cestrum

  50. #170

    Default Re: Schiff's bases

    Well, the MA Phenylacetaldehyde Schiffs base hase some of the Phenylacetaldehyde odor profile, And I'll agree with Bill at TGSC:
    hyacinth green foliage floral mandarin sweet pea

    But also a touch of orangleblossom.

    PK
    Paul Kiler
    PK Perfumes
    http://www.PKPERFUMES.com
    Gold Medal for "Best Aroma"; Los Angeles Artisan Fragrance Salon

  51. #171

    Default Re: Schiff's bases

    Quote Originally Posted by pkiler View Post
    Tuesday, I made the Phenylacetaldehyde MA schiff base, This Morning, it is bright yellow fluid, It's a little thick (clouded), it has a small air bubble slowly rising in the soup,
    PK

    So to follow up, the juice has now cleared up, no cloudiness, or thickness. It seems that the thick stage is in the midst of reaction times.

    The odor is more blended that the first eval.

    Nice little product to make, and make more of...

    PK
    Paul Kiler
    PK Perfumes
    http://www.PKPERFUMES.com
    Gold Medal for "Best Aroma"; Los Angeles Artisan Fragrance Salon

  52. #172

    Default Re: Schiff's bases

    Is it still yellow?
    My base with benzaldehyde turned from orange to brown over time..

  53. #173

    Default Re: Schiff's bases

    yup, still yellow...

    PK
    Paul Kiler
    PK Perfumes
    http://www.PKPERFUMES.com
    Gold Medal for "Best Aroma"; Los Angeles Artisan Fragrance Salon

  54. #174

    Default Re: Schiff's bases

    Guys,

    I do like the enthousiasm about chemistry here, but be warned that just because something changes colour, appearance or scent does not mean youve succesfully made a Schiff base. Unless you have the analytical tools, there is no way of knowing what happened.

    Some of the procedures mentioned here will deliver some amount of the desired product, but as a mixture with the starting material and side products.

    Take it from someone who has been making and isolating chemicals for the last 10 years.

  55. #175

    Default Re: Schiff's bases

    That said, where a material is being used for a practical (including aesthetic) purpose, then ultimately the concern of interest is ordinarily whether that purpose is fully met without any problems, or is not. Even where purity may be lacking, or even if none of the intended compound is generated.

    As you say, without analysis one won't actually know what one has however. But the procedure to get it could be reproducible, and the product could be of use.

    Not that you were saying different!

    For those trying to make a Schiff base for which they have no authentic sample, an idea might be to also try making a Schiff base by the same procedure for which one does have an authentic sample. If the products can't be told apart, then it might be that the method is capable of generating a usefully pure intended Schiff base. If the products can be told apart, then likely the procedure cannot. But it might generate something functionally useful anyway.

  56. #176

    Default Re: Schiff's bases

    I agree that any material may be useful, irregardless its purity, but:

    Quote Originally Posted by Bill Roberts View Post
    could be reproducible
    When I read the posts above I would highly doubt that... (most are on the right track though, but 10% difference is huge when it comes to the sense of smell)

    Regarding your last suggestion: this could work, but only for very similar starting materials (think C12 and C10). In other cases the optimal procedure varies quite a bit depending on the substrates.

  57. #177

    Default Re: Schiff's bases

    I really didn't write clearly. Mostly I meant that if a self-invented procedure (not in any way verified by analysis) fails where it can be tested by sense of smell against an authentic sample, then it's relatively unlikely that it will give high purity Schiff bases in other cases either.

    It might but that wouldn't be my odds-on bet.

    It was meant more as a method of deflating an unrealistic balloon of hope (if that were the case) than a means of assuring anything or utterly ruling anything out.
    Last edited by Bill Roberts; 5th August 2014 at 06:00 PM.

  58. #178

    Default Re: Schiff's bases

    agree

  59. #179
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    Default Re: Schiff's bases

    I don't know jack about chemistry (disclaimer ;P) however the Phenylacetaldehyde that I cooked up with MA smells similar Paul, take from that what you will. Also, the PADMA I've combined with MA lasts longer on a smelling strip than it's counterparts but has a lower odor profile. I've lost steam with this schiffs base project, partly due to the negative criticism but I'm slowly integrating the materials I've bastardized into what I'm doing - atm I'm reconstructing and converting accords, bases and historical perfume blends. Also, the Ethyl Vanilin/MA combination worked well for an Ambrein base I recently made, it really gave it that extra musky-dirty, orange-vanilla, cream-sickle kick... Thought it might be worth mentioning even if it's not a real schiffs base.
    Last edited by JEBeasley; 6th August 2014 at 08:00 AM.
    Justin E. Beasley

  60. #180

    Default Re: Schiff's bases

    Just to point out that PADMA will not react with Methyl Anthranilate to form a Schiff's Base. PADMA stands for Phenylacetaldehyde Dimethyl Acetal; it cannot react.

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