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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 08:52 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 08:59 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 06:59 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 03:21 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?

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