I've heard that you can boil up shredded rhubarb leaves and use the resulting liquid as a pesticide. Has anyone here tried it? Are there any problems? Is it dangerous to people?
Rhubarb leaves are loaded with Oxalic acid. This is toxic to more than insects, it is also corrosive and poisonous.
If you fancy having fewer relatives try rinsing and shredding rhubarb leaves into the next salad you feed them.
Boiling up straining and then boiling down the liquor concentrates the acid nicely, wear gloves and don't spill it on anything you don't want bleached.
Traditionally the insecticide of choice was nicotine not rhubarb.
Maybe I was a little laid back, but seriously the liquor is highly dangerous DON'T get it on your clothes and/or skin, I wouldn't use food preparation utensils without both soaking in several tubs of water and repeated washings afterwards.
Concentrated Oxalic acid is used as a wood bleach. to neutralise the standard method is several gallons (approx 4.5 litres = 1 gallon) of water with 1/2 ounce (12 -15 grams) of household borax per gallon followed by repeated washing with clean water.
Finally, if you must, use glass vessels boiling rhubarb leaves was sometimes used to remove baked on (or in) stains and restore a bright surface to metal cookware - which suggests you would be corroding your pans.
Not something I'm familiar with and my old gardening books (elderly penguins) don't have anything, though they do have nicotine and Bordeaux mixture. You'd be making a solution of Oxalic acid so the best I can do is offer you the Hazcard.
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If you fancy having fewer relatives try rinsing and shredding rhubarb leaves into the next salad you feed them.
Boiling up straining and then boiling down the liquor concentrates the acid nicely, wear gloves and don't spill it on anything you don't want bleached.
Traditionally the insecticide of choice was nicotine not rhubarb.
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Concentrated Oxalic acid is used as a wood bleach. to neutralise the standard method is several gallons (approx 4.5 litres = 1 gallon) of water with 1/2 ounce (12 -15 grams) of household borax per gallon followed by repeated washing with clean water.
Finally, if you must, use glass vessels boiling rhubarb leaves was sometimes used to remove baked on (or in) stains and restore a bright surface to metal cookware - which suggests you would be corroding your pans.
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36. ETHANEDIOIC ACID AND SALTS
Applicable to ammonium ethanedioate (oxalate), sodium ethanedioate (oxalate), potassium ethanedioate (oxalate),
potassium hydrogen ethanedioate-1-ethanedioic acid-2-water (tetroxalate).
HARMFUL Ethanedioic
acid
HARMFUL Potassium
ethanedioate
Trans-butenedioic acid (fumaric acid), cis-butenedioic acid (maleic acid) and butan-1,4-dioic acid
(succinic acid) are also dibasic organic acids but are labelled IRRITANTS and, on very rare occasions,
have been known to cause sensitisation.
If swallowed:
If dust inhaled:
If dust or solution gets in eyes: Flood the eye with gently running tap water for 10 minutes. Seek medical attention.
If spilt on skin or clothes:
If spilt in laboratory:
DISPOSAL [50 g]
STORE
Wash out the mouth and give a glass or two of water. Seek medical attention as soon as possible.
Do not induce vomiting.
Remove the victim to fresh air. If breathing is affected, seek medical attention.
Brush off as much solid as possible. Remove contaminated clothing. Flood the affected area with
large quantities of water. Soak clothes.
Scoop up as much solid as possible. Pour water over the area and apply mineral absorbent.
Dissolve in 10 litres of water and wash to waste down the foul-water drain, diluting further.
With Toxics [T]. If there is no room, they may be stored with General Chemicals (organic) [GC]
in a locked store room.
* SEE CARD, † SEE INDEX
Oxalic acid and oxalates
p Harmful when in contact with the skin and when swallowed.
Solutions stronger than 0.3 M are also HARMFUL.
It is also a strong irritant (causes burns).
DANGEROUS WITH: OXIDISING AGENTS. Violent reactions
may occur.
Harmful when in contact with the skin and when swallowed.
Solutions stronger than 0.3 M are also HARMFUL. p It is also a strong irritant (causes burns).
DANGEROUS WITH: OXIDISING AGENTS. Violent reactions
may occur.
© CLEAPSS 1998
Inorganic Chemistry through Experiment, G F Liptrot, Collins, ISBN 0 263 51591 5.
ETHANEDIOIC ACID AND SALTS
Activity
General use of
solutions
Titrations
Action of heat
Addition of
concentrated
sulphuric acid
As a complexing
agent
Preparation of
esters and salts
Cis-trans
isomerism
Partition constant
1
* SEE CARD, † SEE INDEX
Level of use
Y 9+ with
careful
supervision
Y 12+
Y 12+
Y 12+
Y 12+
Y 12+
Y 12+
Y 12+
GENERAL RISK ASSESSMENTS
Experimental points
Wear eye protection. Solutions should be 0.3 M or less.
Wear eye protection. Pipette-fillers should always be used.
Wear eye protection. If 0.5 g of acid or salt is used, the reaction may be done in a
well-ventilated laboratory; for larger amounts a fume cupboard is required.
Carbon monoxide* is produced along with carbon dioxide*.
Wear eye protection. Use 0.5 g of ethanedioic acid and enough concentrated
sulphuric acid* to cover the solid. Gentle heating will be necessary. At this level, the
reaction may be done in a well-ventilated laboratory, otherwise a fume cupboard is
required. Carbon monoxide* is produced along with carbon dioxide*.
Wear eye protection. Follow instructions1 closely; a large amount of frothing occurs
due to carbon dioxide* evolution.
Wear eye protection. Small-scale reactions are possible in test tubes.
Wear eye protection when using butenedioic acids. Do not inhale the vapours if
heated.
Wear eye protection. The room must be well-ventilated. Butane-1,2-dioic acid
(0.5 to 2 g) can be added to 50 ml of a 1:1 mixture of water and ethoxyethane*.
Solutions may be titrated with solutions of sodium hydroxide*. No mouth pipetting.
© CLEAPSS 1998
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