Desiccants


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Desiccants

 

chemical preparations for drying standing crops. Many contact herbicides (DINOC, dinitro-sec-butyl-phenol, pentachlorophenol, and pentachlorophenates of alkali metals) are used as desiccants. Inorganic compounds that can be used as desiccants include sulfuric acid, arsenous acid, and sodium, magnesium, and calcium chlorates. Because of the danger of explosion, sodium chlorate is usually used in a mixture with sodium pentabromate, and magnesium chlorate is used in a mixture with sodium chloride. Thiocyanates , ethyl and isopropyl xanthates of alkali metals, bis-(ethylxanthogen)-di-, tri-, and tetrasulfides, and calcium cyanamide are also used. Other good desiccants are a mixture of endotal and ammonium sulfate, sodium cis-β-chlo- roacrylate, sodium 2,3,4,5,5-pentachloropenta-2,4-dienate, potassium and sodium cyanates, and the preparations dikvat and parakvat.

For partial drying of plants, most desiccants are used in the form of aqueous solutions or emulsions. The most widely used are chlorates, parakvat, dikvat, and salts of chloroacrylic acid. The standard consumption of chlorates is 10-20 kg per hectare, or kg/ha (in terms of chlorate), and 0.3-2.5 kg/ha for parakvat and dikvat. The last two preparations are highly toxic to animals (LD50 for rats is 17-50 mg/kg).

REFERENCES

Mel’nikov, N. N. Khimiia pestitsidov. Moscow, 1968.
Stonov, L. D. Defolianty i desikanty. Moscow, 1961.
Zakirov, T. S. Khimicheskaia defoliatsiia i desikatsiia khlopchatnika. Tashkent, 1968.

N. N. MEL’NIKOV

References in periodicals archive ?
It is common to classify desiccants as either solid or liquid depending on their normal physical state (although a material such as lithium chloride can be both, absorbing water vapor both as a solid, hydrated salt, or as an aqueous solution).
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Makers of desiccants describe their products as "adsorbers" of moisture.
Today's desiccant technology offers a reliable way of lowering moisture levels without the use of additional costly electrical air conditioning equipment.
The gas dehumidifier relies on proven desiccant technology to control relative humidity independent of the electric air conditioner.
and served in various management positions, culminating in the position of site general manager at an adsorbents and desiccants manufacturing facility.
2001, Novel desiccants based on designed polymeric blends, Journal of Applied Polymer Science 80 (3), pp.
The move toward drop-in packaging solutions began with the development of pharmaceutical-grade desiccant packets, which remain in wide use today.