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FLINN METHOD
#22b Peroxides, Organic
Organic peroxides are particularly dangerous materials that are highly flammable
and explosive. Peroxides are sensitive to heat, shock, friction or contact with
combustible materials. These materials are classified by the EPA as characteristic
(reactive) hazardous wastes. Leftover organic peroxides may be hydrolyzed as part
of an experimental procedure.
Examples
Benzoyl peroxide and lauroyl peroxide
Materials Required
Hydrochloric acid solution, HCl, 6 M
Sodium hydroxide solution, NaOH, 3 M—tenfold volume excess of the material to
be destroyed, in a large glass beaker
Glass stirring rod
pH paper
Plastic spoon (optional)
Overview
When reacted with base, benzoyl peroxide and lauroyl peroxide (the only
substances we catalog for which this procedure is suggested) will cleave between
the two joined oxygen atoms and form sodium benzoate or sodium laurate, which
are soluble in water and innocuous. Use care not to go past the neutral point when
adding acid to the aqueous solution. If the solution is acidic, some benzoic acid
may precipitate out.
(C6H5CO2)2 + 2NaOH → 2C6H5CO2¯Na+ + O2
Procedure
1
Perform this procedure in a fume hood. Wear chemical splash goggles, chemicalresistant
gloves and a lab coat or chemical-resistant apron. Exercise caution
working with dry organic peroxides—they are friction- and shock-sensitive.
5
Flush the neutral solution down the
drain with excess water.
FLINN METHOD
#23 Sulfides, Inorganic
Inorganic sulfides release highly toxic hydrogen sulfide gas on treatment with acid.
These materials are classified by the EPA as characteristic (reactive) hazardous
wastes and may not be disposed of in the trash or drain. Leftover soluble inorganic
sulfides may be oxidized as part of an experimental procedure.
Examples
Sodium sulfide, ammonium sulfide
Materials Required
Sodium hydroxide solution, NaOH, 0.5 M
Sodium hypochlorite solution, NaOCl
Glass stirring rod
Large glass beaker
Overview
Inorganic sulfides are easily oxidized to sulfate ions using sodium hypochlorite as
an oxidizing agent.
Na2S + 4OCl¯ → Na2SO4 + 4Cl¯
A small amount of base is added to keep the solution basic. A basic solution is
needed because inorganic sulfides react with acid to produce highly toxic hydrogen
sulfide gas and the hypochlorite ion is more stable at a higher pH.
The products from the reaction are sulfate salts, which are nonvolatile, odorless
and have low toxicity. These materials can be rinsed down the drain.
Procedure
1
Perform this procedure in a fume hood. Wear chemical splash goggles, chemicalresistant
gloves and a lab coat or chemical-resistant apron.
FLINN METHOD #23 continued on next page.
2
Carefully add a small amount of water
and break up any lumps in the organic
peroxide with a plastic stirring rod. Do
not grind the dry solid.
Water
Organic
Peroxide
3
Pour the material into 3 M sodium
hydroxide solution. Allow to stand
at least 24 hours, stirring frequently.
Benzoyl peroxide has low water
solubility, so frequent agitation is
important to bring the decomposition
reaction to completion.
Organic
Peroxide
3 M NaOH
4
Using pH paper as a monitor, neutralize
the solution with 6 M hydrochloric acid.
6 M
HCI
pH Paper
2
Dissolve the inorganic sulfide in 0.5 M
NaOH solution. For ammonium sulfide,
use 100 mL of NaOH solution for every
10 mL of sulfide solution. NaOH
Inorganic Sulfide
3
Slowly add sodium hypochlorite
solution (bleach) to the inorganic
sulfide. Add 200 mL bleach for each
10 mL of ammonium sulfide or 5 g of
sodium sulfide.
Bleach