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It's workable (and has a long history) to use salicylates from willows, but it's slightly unpleasant on the stomach. It was usually taken as a tea, made directly from the willow bark. Any more concentrated form of salicylic acid (see above) is wart remover and isn't consumed internally.
Nor is it a question of dose, it's a different compound. In fact, salicylic acid is so harmful that it wasn't taken directly (there was a brief Victorian period when it was, as it was much cheaper). The compound prepared from the tree is a sugar called
salicin, and that is oxidised within the body to the acid form. However it's hard to produce large quantities of salicin cheaply. Salicyclic acid was only taken as a drug for a brief period after the development of industrial pharmacy, when salicyclic acid could be synthesised cheaply, without willows, and before the mighty
Bayer of Germany invented
Aspirin as a more acceptable form of it.
Charles Frédéric Gerhardt, one of the illustrious group of self-poisoning chemists, had first set out to synthesise a more acceptable form of salicyclic acid and found that
acetyl salicylic acid was suitable. However his synthesis wasn't very good and he gave up, thinking that the compound was wrong, rather than it just being his process. It was some decades before his original work was really proven to be right, by
Felix Hoffman at Bayer.
Note that WP's claim, "Aspirin, in the form of leaves from the willow tree, has been used for its health effects for at least 2,400 years." is just wrong (and a complete misunderstanding of a childishly simple and correct ref). But that's GA review and MEDRS for you - form over accuracy, every time.
Andy Dingley (
talk)
12:06, 11 November 2017 (UTC)reply
First, salicylates have been used for at least 5000 years, as evidenced by
Ur III, a tablet from
Ur of the Chaldees from, if I recall correctly, roughly 300 years before the birth of the biblical patriarch Abraham. Here's one source.
[1] Salicylate was available in other forms - beaver testicles notably concentrate it in a way that they would apply to toothaches and such, and were used by native Americans; there was even a myth in Europe from classical times that the beaver would castrate itself when hunters grew near to avoid capture. (see
Tractatus de Herbis)
Second, the willow bark salicylates used 5000 years ago were far safer than the only ones allowed to be sold over the counter by responsible medical authorities today.
[2] This is because
salicin comes as a
glycoconjugate that is not taken apart until after it passes through the stomach. By contrast,
aspirin was invented a century ago by industrialists who noticed that the salicylates they sold were causing stomach injury, and who figured it was due to the acid, so (after first trying to "buffer" the acid, e.g.
Bufferin) they put a simple acetyl group over the acid hoping to stop the damage. Same folks who brought you heroin as the non-addictive alternative to morphine (a racket that works to this day).
Wnt (
talk)
16:50, 11 November 2017 (UTC)reply
As willow bark has been mentioned, I think I will have a go at a bit of clarification. Pharmaceutical companies love to synthesize the most active component of any proven natural remedy and market it. Willow Bark contains salicylic acid but the 'therapeutic' dose of Willow Bark has far less salicylic acid per dose, so does not cause the same problems as therapeutic dose of pure salicylic acid nor acetylsalicylic acid. The reason for this is that Willow Bark also contains other compounds that work synergically, which enhance the therapeutic effect of the little Salicylic acid that Willow Bark has per dose. This is why many users of Willow Bark swear blind that it is more effective than drug-store bought acetylsalicylic acid pain killers. Placebo? Doctors take it rather than become dependent on anything stronger and addictive. Also many doctors are closet alcoholics. So even though Willow Bark is far from completely safe for a habitual drinkers is better than acetylsalicylic acid, acetaminophen, ibuprofen, naproxen, etc. These drugs do the kidneys in quicker. Yet, since one's HCP can't earn money from writing 'scripts for Willow Bark – one ends up being proscribed a synthetic. And why not. Your Doctor is running a business and he too, has to earn enough to put his kids through collage – and possible be the first in the street to own a Tesla etc..
Aspro (
talk)
23:15, 11 November 2017 (UTC)reply
That was the idea behind "
Bufferin", but it was generally incorrect. I think it is more accurate to say that
cyclooxygenase enzymes (especially
COX-1) in the stomach are needed to prevent injury, and if salicylate is absorbed there it will inhibit those enzymes.
Wnt (
talk)
22:37, 14 November 2017 (UTC)reply
where can I find literature on anhydrous acid-base equilibria?
It is really frustrating to me as a tutor of organic chemistry that everyone assumes that acid base reactions always take place in water. I need more information about how to estimate pKa of an organic compound in say, ethanol or glacial acetic acid, given a pKa in water and pKb of a conjugate base (and vice versa), as well as the autoionization constant of the target solvent. Also, how would I calculate the change in pKas for polar aprotic solvents?
98.14.205.209 (
talk)
15:41, 11 November 2017 (UTC)reply
It might not be a solvable problem at this point.
Acid_dissociation_constant is our main article, and its "Acidity in nonaqueous solutions" section notes:
These facts are obscured by the omission of the solvent from the expression that is normally used to define pKa, but pKa values obtained in a given mixed solvent can be compared to each other, giving relative acid strengths. The same is true of pKa values obtained in a particular non-aqueous solvent such a DMSO.
As of 2008, a universal, solvent-independent, scale for acid dissociation constants has not been developed, since there is no known way to compare the standard states of two different solvents.
The following ref (cited in that article section) has some information about comparing pKa in different solvents, especially with respect to different structural classes:
Kaljurand, I.; Kütt, A.; Sooväli, L.; Rodima, T.; Mäemets, V.; Leito, I; Koppel, I.A. (2005). "Extension of the Self-Consistent Spectrophotometric Basicity Scale in Acetonitrile to a Full Span of 28 pKa Units: Unification of Different Basicity Scales". J. Org. Chem. 70 (3): 1019–1028.
doi:
10.1021/jo048252w.
PMID15675863.
OK thank you, because I am trying to define the scope of problems that I can cover with my students, and in many cases I have to know much more than my students would need to know (to ace their exams) because their education (and mine) I realize sometimes seem to side-step certain problems with dogmatic assumptions.
98.14.205.209 (
talk)
16:38, 11 November 2017 (UTC)reply
Systems of acid and non-conjugate base (e.g. ammonium bicarbonate, pyridinium dihydrogen phosphate, boric acid - acetate)
Why aren't systems like these covered as extensively in online pages? Almost every web page seems to stop at adding a strong base to a weak acid or strong acid to weak base which is *really frustrating*. I suddenly realize that we didn't really cover many non-conjugate buffers in undergrad (the most we did was ammonium acetate, which to be honest is CHEATING since pKa + pKb = 14 and is really just a hidden version of the acid / conjugate-base problem). Basically we have a weak acid and a weak base whose pKas and pKbs do not add up to 14. Surely there must be a better way than having to brute force it through a system of equations?
98.14.205.209 (
talk)
16:34, 11 November 2017 (UTC)reply
Boric acetate is used as a buffer in
this patent. SciFinder has about 10 hits for "pyridium phosphate", the result-set of which is annotated as being an uncertain ratio, and seem to have been studied as corrosion inhibitors.
DMacks (
talk)
22:21, 11 November 2017 (UTC)reply
The permanent magnets used in constructing Axle Flux Generators are always arranged to have alternate poles such as: N-S-N-S-N-S etc. What would be the effect on the output waveform if I used similar poles such as: N-N-N-N-N etc. — Preceding
unsigned comment added by
Adenola87 (
talk •
contribs)
16:59, 11 November 2017 (UTC)reply
An
axial flux generator? The usual source for building advice on these (small scale wind turbines) is Hugh Piggott's books or
website. You need to alternate the magnets, so that there is a changing flux through the coils. If there is no change of flux, then there's no output.
A long-established design is the
claw pole alternator. This uses a single field coil (so the flux in the armature is always the same direction) and has sets of interleave pole pieces from each end, so that it has the effect of a reversing field.
Andy Dingley (
talk)
19:10, 11 November 2017 (UTC)reply
Unlike most guns with box-like magazines, some have cartridges kept in horizontal pipe-shaped magazines fitted just below their barrels (mostly clutch-action"
lever-action" or "
pump-action" rifles). Such an arrangement may be all a right for
shotguns which always use cartridges with flat front-ends, but in the rifles the cartridges' front end is never flat, it may not be sharp ( like AK-47s etc.), and is rounded to some extent, but is still narrow enough to work as a fire-pin against the front-to-it cartridge lying with its most sensitive part (cap) just touching it (bullet-tip of the neighbor behind). Is this arrangement not considered risky ? Besides the gun may also receive some unexpected jerk etc. ?
Jon Ascton (talk)17:25, 11 November 2017 (UTC)reply
It's called a tube magazine, and it's used on lever-action rifles like the
Winchester Model 94. There are a lot of videos of people fooling around with this configuration trying to set off a chain reaction in the tube. Conventional wisdom is that pointy bullets are dangerous in tube magazines, and that all rounds for such rifles should use blunt-headed shapes and soft alloys. Hornady makes a plastic-capped pointy round that's supposed to be safe, but most opinions seem to be that the added ballistic performance isn't worth the cost of the ammunition - lever-action rifles aren't really made for long-range fire, so the blunt ballistics make no real difference at ranges for which such guns are normally used. Acroterion(talk)18:10, 11 November 2017 (UTC)reply
Rifle primers are designed to allow for light strike. For example, an
M16 rifle has a free floating firing pin. When the bolt is retracted and closed as part of the cycle, the firing pin can strike the rifle primer and spec for the primer must allow for a light strike. The hammer spring must be sufficiently strong to project the firing pin into the primer. Pistol primers, however, are much more sensitive. Firing pins for pistols have many more safeguards to prevent any strike. --
DHeyward (
talk)
06:24, 12 November 2017 (UTC)reply
Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the
current reference desk pages.
It's workable (and has a long history) to use salicylates from willows, but it's slightly unpleasant on the stomach. It was usually taken as a tea, made directly from the willow bark. Any more concentrated form of salicylic acid (see above) is wart remover and isn't consumed internally.
Nor is it a question of dose, it's a different compound. In fact, salicylic acid is so harmful that it wasn't taken directly (there was a brief Victorian period when it was, as it was much cheaper). The compound prepared from the tree is a sugar called
salicin, and that is oxidised within the body to the acid form. However it's hard to produce large quantities of salicin cheaply. Salicyclic acid was only taken as a drug for a brief period after the development of industrial pharmacy, when salicyclic acid could be synthesised cheaply, without willows, and before the mighty
Bayer of Germany invented
Aspirin as a more acceptable form of it.
Charles Frédéric Gerhardt, one of the illustrious group of self-poisoning chemists, had first set out to synthesise a more acceptable form of salicyclic acid and found that
acetyl salicylic acid was suitable. However his synthesis wasn't very good and he gave up, thinking that the compound was wrong, rather than it just being his process. It was some decades before his original work was really proven to be right, by
Felix Hoffman at Bayer.
Note that WP's claim, "Aspirin, in the form of leaves from the willow tree, has been used for its health effects for at least 2,400 years." is just wrong (and a complete misunderstanding of a childishly simple and correct ref). But that's GA review and MEDRS for you - form over accuracy, every time.
Andy Dingley (
talk)
12:06, 11 November 2017 (UTC)reply
First, salicylates have been used for at least 5000 years, as evidenced by
Ur III, a tablet from
Ur of the Chaldees from, if I recall correctly, roughly 300 years before the birth of the biblical patriarch Abraham. Here's one source.
[1] Salicylate was available in other forms - beaver testicles notably concentrate it in a way that they would apply to toothaches and such, and were used by native Americans; there was even a myth in Europe from classical times that the beaver would castrate itself when hunters grew near to avoid capture. (see
Tractatus de Herbis)
Second, the willow bark salicylates used 5000 years ago were far safer than the only ones allowed to be sold over the counter by responsible medical authorities today.
[2] This is because
salicin comes as a
glycoconjugate that is not taken apart until after it passes through the stomach. By contrast,
aspirin was invented a century ago by industrialists who noticed that the salicylates they sold were causing stomach injury, and who figured it was due to the acid, so (after first trying to "buffer" the acid, e.g.
Bufferin) they put a simple acetyl group over the acid hoping to stop the damage. Same folks who brought you heroin as the non-addictive alternative to morphine (a racket that works to this day).
Wnt (
talk)
16:50, 11 November 2017 (UTC)reply
As willow bark has been mentioned, I think I will have a go at a bit of clarification. Pharmaceutical companies love to synthesize the most active component of any proven natural remedy and market it. Willow Bark contains salicylic acid but the 'therapeutic' dose of Willow Bark has far less salicylic acid per dose, so does not cause the same problems as therapeutic dose of pure salicylic acid nor acetylsalicylic acid. The reason for this is that Willow Bark also contains other compounds that work synergically, which enhance the therapeutic effect of the little Salicylic acid that Willow Bark has per dose. This is why many users of Willow Bark swear blind that it is more effective than drug-store bought acetylsalicylic acid pain killers. Placebo? Doctors take it rather than become dependent on anything stronger and addictive. Also many doctors are closet alcoholics. So even though Willow Bark is far from completely safe for a habitual drinkers is better than acetylsalicylic acid, acetaminophen, ibuprofen, naproxen, etc. These drugs do the kidneys in quicker. Yet, since one's HCP can't earn money from writing 'scripts for Willow Bark – one ends up being proscribed a synthetic. And why not. Your Doctor is running a business and he too, has to earn enough to put his kids through collage – and possible be the first in the street to own a Tesla etc..
Aspro (
talk)
23:15, 11 November 2017 (UTC)reply
That was the idea behind "
Bufferin", but it was generally incorrect. I think it is more accurate to say that
cyclooxygenase enzymes (especially
COX-1) in the stomach are needed to prevent injury, and if salicylate is absorbed there it will inhibit those enzymes.
Wnt (
talk)
22:37, 14 November 2017 (UTC)reply
where can I find literature on anhydrous acid-base equilibria?
It is really frustrating to me as a tutor of organic chemistry that everyone assumes that acid base reactions always take place in water. I need more information about how to estimate pKa of an organic compound in say, ethanol or glacial acetic acid, given a pKa in water and pKb of a conjugate base (and vice versa), as well as the autoionization constant of the target solvent. Also, how would I calculate the change in pKas for polar aprotic solvents?
98.14.205.209 (
talk)
15:41, 11 November 2017 (UTC)reply
It might not be a solvable problem at this point.
Acid_dissociation_constant is our main article, and its "Acidity in nonaqueous solutions" section notes:
These facts are obscured by the omission of the solvent from the expression that is normally used to define pKa, but pKa values obtained in a given mixed solvent can be compared to each other, giving relative acid strengths. The same is true of pKa values obtained in a particular non-aqueous solvent such a DMSO.
As of 2008, a universal, solvent-independent, scale for acid dissociation constants has not been developed, since there is no known way to compare the standard states of two different solvents.
The following ref (cited in that article section) has some information about comparing pKa in different solvents, especially with respect to different structural classes:
Kaljurand, I.; Kütt, A.; Sooväli, L.; Rodima, T.; Mäemets, V.; Leito, I; Koppel, I.A. (2005). "Extension of the Self-Consistent Spectrophotometric Basicity Scale in Acetonitrile to a Full Span of 28 pKa Units: Unification of Different Basicity Scales". J. Org. Chem. 70 (3): 1019–1028.
doi:
10.1021/jo048252w.
PMID15675863.
OK thank you, because I am trying to define the scope of problems that I can cover with my students, and in many cases I have to know much more than my students would need to know (to ace their exams) because their education (and mine) I realize sometimes seem to side-step certain problems with dogmatic assumptions.
98.14.205.209 (
talk)
16:38, 11 November 2017 (UTC)reply
Systems of acid and non-conjugate base (e.g. ammonium bicarbonate, pyridinium dihydrogen phosphate, boric acid - acetate)
Why aren't systems like these covered as extensively in online pages? Almost every web page seems to stop at adding a strong base to a weak acid or strong acid to weak base which is *really frustrating*. I suddenly realize that we didn't really cover many non-conjugate buffers in undergrad (the most we did was ammonium acetate, which to be honest is CHEATING since pKa + pKb = 14 and is really just a hidden version of the acid / conjugate-base problem). Basically we have a weak acid and a weak base whose pKas and pKbs do not add up to 14. Surely there must be a better way than having to brute force it through a system of equations?
98.14.205.209 (
talk)
16:34, 11 November 2017 (UTC)reply
Boric acetate is used as a buffer in
this patent. SciFinder has about 10 hits for "pyridium phosphate", the result-set of which is annotated as being an uncertain ratio, and seem to have been studied as corrosion inhibitors.
DMacks (
talk)
22:21, 11 November 2017 (UTC)reply
The permanent magnets used in constructing Axle Flux Generators are always arranged to have alternate poles such as: N-S-N-S-N-S etc. What would be the effect on the output waveform if I used similar poles such as: N-N-N-N-N etc. — Preceding
unsigned comment added by
Adenola87 (
talk •
contribs)
16:59, 11 November 2017 (UTC)reply
An
axial flux generator? The usual source for building advice on these (small scale wind turbines) is Hugh Piggott's books or
website. You need to alternate the magnets, so that there is a changing flux through the coils. If there is no change of flux, then there's no output.
A long-established design is the
claw pole alternator. This uses a single field coil (so the flux in the armature is always the same direction) and has sets of interleave pole pieces from each end, so that it has the effect of a reversing field.
Andy Dingley (
talk)
19:10, 11 November 2017 (UTC)reply
Unlike most guns with box-like magazines, some have cartridges kept in horizontal pipe-shaped magazines fitted just below their barrels (mostly clutch-action"
lever-action" or "
pump-action" rifles). Such an arrangement may be all a right for
shotguns which always use cartridges with flat front-ends, but in the rifles the cartridges' front end is never flat, it may not be sharp ( like AK-47s etc.), and is rounded to some extent, but is still narrow enough to work as a fire-pin against the front-to-it cartridge lying with its most sensitive part (cap) just touching it (bullet-tip of the neighbor behind). Is this arrangement not considered risky ? Besides the gun may also receive some unexpected jerk etc. ?
Jon Ascton (talk)17:25, 11 November 2017 (UTC)reply
It's called a tube magazine, and it's used on lever-action rifles like the
Winchester Model 94. There are a lot of videos of people fooling around with this configuration trying to set off a chain reaction in the tube. Conventional wisdom is that pointy bullets are dangerous in tube magazines, and that all rounds for such rifles should use blunt-headed shapes and soft alloys. Hornady makes a plastic-capped pointy round that's supposed to be safe, but most opinions seem to be that the added ballistic performance isn't worth the cost of the ammunition - lever-action rifles aren't really made for long-range fire, so the blunt ballistics make no real difference at ranges for which such guns are normally used. Acroterion(talk)18:10, 11 November 2017 (UTC)reply
Rifle primers are designed to allow for light strike. For example, an
M16 rifle has a free floating firing pin. When the bolt is retracted and closed as part of the cycle, the firing pin can strike the rifle primer and spec for the primer must allow for a light strike. The hammer spring must be sufficiently strong to project the firing pin into the primer. Pistol primers, however, are much more sensitive. Firing pins for pistols have many more safeguards to prevent any strike. --
DHeyward (
talk)
06:24, 12 November 2017 (UTC)reply