- Sulphuryl fluoride
Sulphuryl fluoride has been developed as an effective fumigant for controlling dry wood termites. This gas has outstanding dispersion and penetrating qualities which permit it to infiltrate termite tunnels and crevices and destroy the insects. Sulphuryl fluoride does not escape through plastic sheets used in structural fumigation as rapidly as methyl bromide or other organic fumigants. Because this gas is odourless, chloropicrin, discharged separately, is recommended as a warning agent.
Description
Common Name:
Sulphuryl fluoride |
Chemical Name:
Sulphuryl fluoride |
Chemical formula:
SO2F2 |
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Physical Properties | |||||||||||||||||||||||||||||||||||||||||||||||||||
State:
Odourless & Colourless Gas |
Odour:
None |
Boiling Point :
-55.2°C |
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Freezing Point : | Molecular Weight:
102.06
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Specific gravity:
i) At gaseous stage : 2.88 |
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Melting Point:
-120°C |
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ii) At liquid stage :
1.342 at 4°C |
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Latent Heat of Vapourisation:
79.5 BTU/lb at -55.2°C |
Flammability :
Nonflammable |
Solubility in water:
0.075 g/100 g at 25°C |
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Chemical Properties
Non-corrosive, relatively unreactive and harmless to wide variety of household materials |
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Relation between weight and volume of Liquid:
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Relation between dosages and concentration of Gas in air
1Ounces per 1000 cubic feet or milligrammes per litre |
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Natural Vapour Pressure at 20 0 C:
10°C (50°F) 9 150 mm Hg
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Mode of Action:
Sulfuryl fluoride is thought to inhibit the glycolysis and fatty acid cycles via the release of fluoride ions in the insects, thereby depriving them of energy necessary for survival. |
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Threshold Limit value (TLV):
5 ppm |
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Method of Evolution as a fumigantFrom steel cylinders under natural pressure |
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Effects on different commodities
Effect on Metals, Paints, Enamels, Plastics, etc.:No effects on Metals, paper, leather, rubbers, plastics, clothes, wall papers and other household articles.Effect on Plants:Germination of Seeds: Does not affect germination.Effects on Plant Products:Forms residual fluorides in food stuff in low quantities, but in certain items such as cheese, meat etc., high quantity of fluoride is formed. |
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Toxicity:Although highly toxic to humans acutely exposed, there have been few reports of accidental poisoning. This may be due to the fact that sulphuryl fluoride aerates very rapidly from fumigated buildings and also because, in its present usage, it is only applied by properly qualified operators. Its mammalian toxicity by inhalation, is about equal to that of methyl bromide. Sulphuryl fluoride is generally very toxic to all postembryonic stages of insects (Kenaga, 1957b; Bond and Monro, 1961), but the eggs of many species are extremely resistant. It has been suggested that this resistance is largely due to the impenetrable nature of the eggshell layers to this chemical (Outram, 1967). |
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Residues
Conversion: Residual fluorides Residues : Food Articles- Very low.. |
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Poison Symptoms
Respiratory irritation, central nervous system depression and then excitement. |
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PrecautionsDo not expose to the Gas for longer period. The safe periods are 7 hr. at 200 ppm; 1 hr at 400 ppm; 5 minutes at 2000 ppm. The threshold limit is 5 ppm for repeated 8 hr exposure for five days. Special canister meant for this fumigant alone should be used. Alternatively, a self breathing apparatus should be used. |
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First Aid:“Send for a doctor in case of accident. If a person should be overcome from breathing this gas, immediately place patient in fresh air, face downward, with head slightly below level of lungs. Keep warm. If breathing stops, give artificial respiration. Note to physician: First symptoms expected are those of nausea, respiratory irritation and central nervous system depression; excitation may follow. Treat symptomatically. There is no known antidote.” |
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Usage as Fumigant
Extremely toxic to all stages of insects except egg stage which is tolerant even at high concentration. It has since been used to control termites and wood boring insects in timber. |
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Dosage
Empty structures, wood: 32 g/m3 for 24 hr at 10 to 14°C 16 g/m3 for 24 hr at 20°C.
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