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[*] posted on 4-9-2011 at 05:38
Oxalic acid from Tea


Im want some Oxalic acid, but looked around the local hardware store and found nothing... black tea contains a high amount of Oxalic acid... how could i extract it? there are ways to extract the Caffeine from tea, so how can u extract oxalic acid, would appreciate any help :)



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[*] posted on 4-9-2011 at 05:50


http://www.ebay.com/itm/Oxalic-Acid-99-pure-2-lb-bags-/30059...

Free shipping and only $13 for a 2 LB bag. A thought experiment would indicate it would take many dollars worth of tea to get even a portion of the 2 pound bag listed above.




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[*] posted on 4-9-2011 at 05:55


Australia is stricked with importation of chemicals i think... and if the extraction is easy enough then i wouldnt mind trying



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[*] posted on 4-9-2011 at 06:14


If there was much oxalic acid in tea it would be too toxic to drink.
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[*] posted on 4-9-2011 at 06:28


but is there a way to do it, i am willing to try



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[*] posted on 4-9-2011 at 06:33


See the attached PDF.


Attachment: biochemj00962-0033.pdf (343kB)
This file has been downloaded 523 times

If you're up for experimentation, oxalic acid has been made by heating sawdust plus NaOH. Also ethylene glycol antifreeze might be a good starting point, say oxidising it with NaOCl with a bit of NiCl2 as a catalyst.

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[*] posted on 4-9-2011 at 06:43


If I remember right, it seems allot of cleaning products have Oxalic Acid in them. Actually yes, "BARKEEPERS FRIEND" a powder used to clean brass copper, and the such is oxalic acid and some other things.



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[*] posted on 4-9-2011 at 06:47


Oxalic acid is used in bee keeping. It kills pests that infect poor, hard working little bees. :)
If you've got such stores where you live, they ought to have it.

Extracting it from tea is extremely inefficient.




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[*] posted on 4-9-2011 at 06:48


Quote: Originally posted by not_important  
See the attached PDF.


So to sum it up, add HCl to a solution of tea, heat for 30 minutes, and then cool the solution in a ice bath to precipitate the oxalic acid... say you done large scale...




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[*] posted on 4-9-2011 at 06:49


alsosome deck cleaners are oxalic acid
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[*] posted on 4-9-2011 at 06:57


Quote: Originally posted by Chemistry Alchemist  
Australia is stricked with importation of chemicals i think
Oxalic acid is used in wood finishing as "wood bleach". Just find your local purveyor of suppliers to cabinet and furniture makers.
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[*] posted on 4-9-2011 at 07:03


Does rhubarb grow in AU? http://en.wikipedia.org/wiki/Rhubarb

If so, the oxalic acid content would be much higher than tea (but still low enough to be impractical, and would require separation of the other acids, e.g. malic).

I would try and make it from anti-freeze (but, I can just buy it;))

Cheers,

O3




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[*] posted on 4-9-2011 at 08:20


Oxidise sugar (sucrose) with conc. or 68 % HNO3 (some V2O5 helps, apparently). Interesting synth. but surplus to requirements, seen as oxalic acid is so OTC... There's a thread on it on this forum.



[Edited on 4-9-2011 by blogfast25]




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[*] posted on 4-9-2011 at 21:02


How would i get my hands on V2O5?




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[*] posted on 5-9-2011 at 01:45


In relation to the sawdust and NaOH Method. It seems that this synthesis was used as a commercial source of oxalic acid for many years.

http://pubs.acs.org/doi/abs/10.1021/ie50387a003
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[*] posted on 5-9-2011 at 03:59


Quote: Originally posted by Chemistry Alchemist  
How would i get my hands on V2O5?


Pottery stores: it's used as a yellow pigment. But the reaction appears to work w/o it too, going by my experience. It even works with quite dilute HNO3 (I used 38 %).

[Edited on 5-9-2011 by blogfast25]




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[*] posted on 5-9-2011 at 07:10


with the sawdust and sodium hydroxide method, how would you do this synthesis?



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[*] posted on 5-9-2011 at 08:06


Quote: Originally posted by Chemistry Alchemist  
with the sawdust and sodium hydroxide method, how would you do this synthesis?


Search online for The utilisation of wood-waste
By Ernst Hubbard
, an early 20th century book out of copyright

OR

Google sawdust sodium hydroxide site:www.sciencemadness.org

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[*] posted on 5-9-2011 at 11:48


Quote: Originally posted by Chemistry Alchemist  
Im want some Oxalic acid, but looked around the local hardware store and found nothing... black tea contains a high amount of Oxalic acid... how could i extract it? there are ways to extract the Caffeine from tea, so how can u extract oxalic acid, would appreciate any help :)


In my youth people would boil rhubarb leaves (which contain
oxalate's to clean their pots. Iron pot NOT aluminium!

Trivia - Why is the Dieffenbachia plant called Dumb cane?

Byda are you sure the oxalate in tea is oxalic acid? Wiki-P
sez - calcium oxalate.

---------
Scanned and you know what that means!

Toxicants Occurring Naturally in Foods
National Academy of Sciences 1973


ACUTE TOXIC EFFECTS

For many years case reports have appeared in textbooks and in the literature of acute poisoning from
ingestion of oxalate-containing plants, particularly those in the Polygonaceae family and particularly the
species rhubarb (Rheum rhaponticum L.) and sorrel grass (Rumex acetosa L.). Because of the fact that
these plants are known to contain a somewhat higher oxalate content than most other foods, the cause of
the symptoms has almost invariably been attributed to this factor. A number of textbooks on poisoning or
poisonous plants discuss the role of (20-26) oxalic, acid. Symptoms are said to be similar to those noted
in hu man beings ingesting oxalic acid, and the authors stress the occurrence of corrosive effects in the
mouth or intestinal tract, and of gastric hemorrhage, renal colic or hematuria, and sometimes
convulsions. Other authors have expressed doubt as to the role of oxalate content in rhubarb poisoning.
For example, Sollmann (27) doubts if the oxalate content of rhubarb leaves is responsible for the
poisoning. Locket (28) states that fatal poisoning by rhubarb leaves is probably mythical and that a
person would need to eat some 4 kg of rhubarb to get the lowest recorded fatal dose of oxalic acid. Drill
"mentions that the oxalate content of vegetables such as rhubarb and spinach has no "significance unless
an unlikely degree of indulgence ... is assumed." He points out that this may not be the case in cattle
eating very large quantities of vegetable matter.

Although there is no question that the ingestion of sufficient (about 5 g or more) oxalic acid as crystals
or in solution by human beings can be fatal, with associated corrosive gastroenteritis, shock, convulsive
symptoms, low plasma Ca, high plasma oxalates, and renal damage a careful examination of some of
the alleged cases of oxalate poisoning from rhubarb allows some question as to the etiology. A case that
has been repeatedly quoted is that reported by Robb." This report, published in 1919, is a brief letter to
the editor of the Journal of the American Medical Association. A housewife had prepared rhubarb for
supper by frying some of the leaves for greens and by boiling the stalks. The husband ate the stalks but
only a small quantity of the leaves. Some 12 h later the housewife developed cramp-like abdominal pains
and by about 50 h after ingestion of the rhubarb she developed symptoms of shock, vomited a brownish
fluid, and aborted a 6-week-old fetus. The woman died some hours later, and it was mentioned that there
was some bleeding from the nose after death. The husband appeared to have few symptoms except for
feeling weak and dizzy the day following ingestion of the rhubarb. There was no postmortem examination
nor was there any analysis of the ingested plant. No mention was made of oxalate crystals in the urine or
of any disturbance of kidney function. No description was given of corrosive effects in the mouth.

A more recent case is that reported by Tallqvist and Vddndnen (33) of the death of a child from oxalic
acid poisoning caused by eating rhubarb leaves. In this instance a 5-yr-old girl, along with other children
in an orphanage, was said to have eaten some raw rhubarb stalks and in addition had been fed some
rhubarb leaves by her friends. There was no evidence as to the quantity of leaves or stalks ingested. No
immediate symptoms were reported, but later in the same day the child became drowsy and would not
eat. She eventually vomited a dark material; she was treated with sedatives and developed coma and
some reduction in urinary output. No oxalate crystals in the urine were mentioned, but it was stated that a
qualitative oxalic acid test was strongly positive. No postmortem examination was done. Death, however,
was definitely attributed to oxalic acid in the rhubarb leaves and stalks.

A second case was mentioned of a 4-yr-old girl with abdominal pain and vomiting the day after eating
raw rhubarb. Vomiting persisted for some 5 days, following which the patient was hospitalized. It was
established that uremia and anuria were present. An increase in potassium in the blood was noted, but
the blood calcium was not determined. At autopsy this patient showed the typical picture of a lower
nephron nephrosis, but no oxalate crystals were found. The authors consider the etiology of this case as
not being clearly established.

Certainly neither of these cases appeared to fit the typical picture of a corrosive gastroenteritis that is
known to follow ingestion of oxalic acid. Furthermore, it is rather doubtful that oxalic acid exists in the free
form in plants. 14 The oxalates exist in vegetables such as spinach and rhubarb principally as the calcium
or potassium salts. An extensive review by Jeghers and Murphy 35 on oxalate metabolism indicates that
the oxalate content of spinach is actually not very different from that in rhubarb. It is thus apparent that the
difference in oxalate content between rhubarb leaves or stalks and other common foods, such as spin-
ach, is scarcely sufficient to establish rhubarb as a poison. Furthermore, the form in which the oxalate is
present seems unlikely to be capable of causing a corrosive tissue change.

There seems to be a scarcity of experimental work on this subject. Tanner and Tanner, however, quote
a report by Maue that he and five other individuals repeatedly ate cooked rhubarb leaves without effect
and that these leaves contained 0.4% oxalate. Maue believed oxalates were not responsible for
previously reported illnesses.

Although it is possible that, as stated by Locket, some of the reports of poisoning from rhubarb leaves
are coincidental, there does seem to be a certain amount of evidence that rather severe symptoms have
been produced at times from this source. It is somewhat remarkable that toxicologists have not generally
considered the role that might be played by various toxic anthraquinone derivatives present in these spe-
cies (31) (see Chapter 15). In a recent monograph, there is considerable discussion of the chemistry of
the anthraquinone type of purgative, andit has been pointed out that these compounds may exist in both
the roots and stems of species such as rhubarb or sorrel grass. It has also been found that the glycoside
is probably the active form of the compound and that the reduced form of the quinone may be oxidized on
storage. It therefore seems possible that these substances may have been involved in some of the
cases.

A recent report by Streicher" makes this suggestion. In this instance a 6-yr-old girl and her 4-yr-old
brother ate the stems and leaves of raw rhubarb in quantities varying from 20 to 100 g. Both developed
profuse vomiting within 2 h and eventually developed slight icterus and enlargement of the liver. The girl
developed a renal insufficiency and a 4+ albumin in the urine. It is significant that no oxalates were
present in the urine in this case. Recovery followed extracorporeal hemodialysis. Streicher suggests that
these cases could scarcely have been attributed to oxalates, since the ingestion of the latter would have
been of the order of only 0.2-0.8 g. He points out that 200 g of rhubarb stalk, 300 g of red beets, 150 g of
celery, or 200 g of spinach would have furnished the same amount of oxalate as that eaten by the girl.

It was also stated in this paper that the anthraquinone glycosides are present in the leaves, especially
in the early summer, and that in their fresh state they are extremely irritating. The content of anthra-
quinones could be as high as 0.5-1% of the weight of the fresh leaf. A study with human volunteers by
Schmid" showed that 10-20 g of fresh rhubarb leaves caused immediate vomiting. Streicher proposes
that the highly irritating reduced forms of the anthraquinone glycosides are likely to be absorbed readily
and are probably responsible for toxic effects in the liver and kidney.

Another example of confusion as to the etiology of the toxic effects of an oxalate-containing plant is
discussed in a recent study of the toxic principle in Dieffenbachia, an ornamental plant." The juice of this
plant has been known for centuries to cause a severe local irritation in the mouth, the cause allegedly
being its content of calcium oxalate crystals. The mechanism was shown to be due to the presence of a
labile proteinlike substance that was capable of causing histamine release.

There has been much interest in the nature of the toxic effects in sheep and cattle grazing on plants
containing very high levels of oxalates, such as Halogeton glomeratus and Oxalis cernua. The ability of
the rumen organisms to metabolize oxalates appears to be limited; if the intake is sufficient, both acute
and chronic effects occur. 11,41

James" considers that there are three syndromes following excessive oxalate ingestion in ruminants:
the first related to acute hypocalcernia, the second to vascular damage to the gut but no hypocalcernia,
and the third to gradual renal insufficiency from calcium oxalate deposits. Cattle are less frequently
involved than sheep, perhaps due to their grazing patterns. Abnormalities in some serum enzymes-e.g.,
serum glutamic oxalacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and
lactic acid dehydrogenase (LDH)-have been observed in sheep.

The evidence for oxalate as the cause of ruminant toxicity from grazing on Halogeton and similar
plants seems reasonable. However, no studies were found in which an effort was made to uncover other
toxic principles in these plants.

It is obvious from this review of the literature that, in spite of many reports of human poisoning attributed
to oxalic acid in plants, those cases described in any detail bear little, if any, resemblance to those known
to have occurred from the chemical oxalic acid. There seems to be little evidence for a corrosive action
on the mouth, esophagus, or stomach. The onset of symptoms seems to be delayed, and there is no
apparent uniformity regarding the matter of oxaluria. A review of inquiries at the National Clearinghouse
for Poison Control Centers 43 shows 18 reported episodes of eating of rhubarb leaves in the years 1959
through 1964; no fatalities occurred, and only five instances of nonspecific symptoms such as vomiting,
diarrhea, or abdominal cramps were reported. It is possible that oxalates may play a role in some cattle
poisoning, but it appears much more likely that toxic anthraquinone glycosides may have been involved in
human cases. Seasonal variations in glycoside content and alterations during cooking would seem to be
important variables in the toxic actions. Additional toxicologic work is needed to clarify the nature of any
toxic principles in rhubarb leaves and in other species of Polygonaceae.


CHRONIC EFFECTS
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[*] posted on 5-9-2011 at 19:16


I was reading an article n extracting it from Rubarb leaves, seems pretty easy but one thing confused me... it says once the solution has extracted all the Oxalic Acid from the Leaves, take the leaves out and then add dd one gram of precipitated chalk to the rhubarb mixture for each 100 grams 1 gram of precipitated chalk to every 100 grams f leaves... but i dont know what they mean by precipitated chalk....

Read more:
How to Extract Oxalic Acid from Rhubarb Leaves
eHow.com http://www.ehow.com/how_5941703_extract-oxalic-acid-rhubarb-...




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[*] posted on 6-9-2011 at 03:59


By 'precipitated chalk' here is meant a clean grade of calcium carbonate. The CaCO3 reacts with the oxalic acid and insoluble calcium oxalate is formed. Later the mixture of CaCO3/CaOx will be treated with H2SO4, forming insoluble CaSO4, CO2 and oxalic acid. Filtering and crystallising then yields the oxalic acid. But you need an awful lot of rhubarb leaves for a bit of OA...

[Edited on 6-9-2011 by blogfast25]




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[*] posted on 6-9-2011 at 04:14


Yeah, and i just asked my parents if when you buy rhubarb if the leaves are attached still and they said no... :/




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[*] posted on 6-9-2011 at 06:38


Quote: Originally posted by Chemistry Alchemist  
Yeah, and i just asked my parents if when you buy rhubarb if the leaves are attached still and they said no... :/


You could get the leaves from an allotment (do ask!), as they have no value to the grower.

If you can't get any 'precipitated chalk', finely crushed limestone should also work. Note that your ehow article only gives you calcium oxalate, not oxalic acid. You still need to convert the oxalate to oxalic acid. OA can be recystallised real easily for purification: it forms really nice needle like crystals, the purer the larger (generally speaking)...

Citric acid can be obtained from lemon juice with a fairly similar procedure.

[Edited on 6-9-2011 by blogfast25]




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[*] posted on 6-9-2011 at 15:52


wood sorrel, that contains oxalic acid too, dont know if it grows in Oz tho
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[*] posted on 6-9-2011 at 18:02


Quote: Originally posted by D4RR3N  
wood sorrel, that contains oxalic acid too, dont know if it grows in Oz tho


Sorrel?! Ding.


Sorrel refers to plants of either the genus Oxalidaceae e.g., Oxalis pes-caprae L
"Bermuda buttercup", or Rumex e.g., Rheum rhaponticum L "Ruhubarb"; Rumex crispus
L "Dock sorrel". Both plants contain soluble oxalates. /djh/


FATAL OXALIC ACID POISONING FROM SORREL SOUP
The Lancet 23/30 December, 1989
Merè Farrè, Judith Xirgu, Antonio Salgado, Ramón Peracaula
Hospital General De Valle Hebrat,
00035 Barcelona, Spain
Ramón Reig, Pere Sanz
Hospital Clininco Provinical, Barcelona

SIR,-- Accidental poisoning by plants containing oxalic add is uncommon [1,2] and we
describe a fatal case of poisoning due to ingestion of sorrel (Rumx crispus). Oxalic acid
has a corrosive action upon the digestive tract. Once it has been absorbed it reacts with
calcium in plasma and insoluble calcium oxalate tends to precipitate in organs such as
kidneys, blood vessels, heart, lungs, and liver; this reaction may also produce
hypocalcaernia.

A 53-year-old man, with a 4-year history of insulin-dependent diabetes, who was a heavy
smoker and drinker, was admitted to hospital because of vomiting, diarrhoea, and
progressive impairment of consciousness soon after the ingestion of a vegetable soup
containing about 500 g of sorrel. He had metabolic acidosis, hypocalcaernia (total calcium
6-3, ionised calcium 2-3 mg/dl); extensive Ever cell necrosis, as evidenced by enzyme
studies and prothrombin ratio (8%); and raised blood urea (18-5 mmol/l) and serum
creatinine (534 umol/l) levels.

The patient went into deep coma with respiratory depression (requiring mechanic
ventilation), kidney and liver failure, and severe metabolic acidosis and hypocalcaemia.
Disturbances in cardiac rhythm progressed to ventricular fibrillation, and this was the cause
of death, 2 hours after the admission, while the patient was on dialysis. A screen for
common hepatotoxins was negative.

Necropsy revealed hepatic centrilobular necrosis, swelling and retraction of glomeruli,
and crystals of calcium oxalate in renal cortex vessels and capillaries of liver, lung and
heart. These findings were consistent with the clinical picture.

In the few reported cases of oxalic acid intoxication, tubular oxalosis has been the main
feature, and hepatic involvement has not been as severe as it was in the present case. The
mean lethal dose of oxalic acid for adults has been estimated as 15-30 g although
amounts lower than 5 g can be fatal. [3] This man ingested 6-8 g oxalic acid. Plants
containing oxalic acid are used in cooking and for medicine purposes, and awareness of
their hazardous potential is important.



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