Drying agent Drierite

Another valuable drying agent of general application is anhydrous calcium sulphate, marketed under the name of Drierite. It is rapid in its action, but has only a limited drying capacity because it forms the hydrate 2CaS04,H20 and thus combines with only 6-6 per cent, of its weight of water. The vapour pressure of the system ... 

You see that vacuum adapter stuck to the top of the condenser in fig. 7a Well, a closer look at it in fig. 7b will show that it has some drying agent sandwiched between two cotton balls and the nipple (tee heel) sealed with plastic wrap or foil. The drying agent can be either a commercial product called Drierite or calcium chloride. This attachment is placed on top of a condenser when refluxing solutions that have no water in them and must remain that way during the time they are refluxed. All this is to prevent moisture in the outside air from coming into contact with the cold surface of the of the inside walls of the condenser. This will surely happen and the condensed outside-air water will drip down into the reaction flask and ruin the experiment. This is not so much a... 

Calcined Anhydrite. Soluble anhydrite, or second-settle stucco, has physical properties similar to those of gypsum plaster. It hydrates to the dihydrate rapidly in water. Its outstanding property is its extreme affinity for any moisture, which makes it a very efficient drying agent (see Desiccants). In ambient moisture-laden air, it readily hydrates to hemihydrate. Soluble anhydrite, under the trade name Drierite, is widely used as a desiccant in the laboratory and in iadustry. A small amount is also used as an insecticide carrier. Small amounts of soluble anhydrite are unintentionally produced in most commercial calciners during hemihydrate production. 

N. Y., 3rd edn, 1970]. Acetone was shaken with Drierite (25g/L) for several hours before it was decanted and distd from fresh Drierite (lOg/L) through an efficient column, maintaining atmospheric contact through a Drierite drying tube. The equilibrium water content is about lO M. Anhydrous Mg(C104)2 should not be used as drying agent because of the risk of EXPLOSION with acetone vapour. 

Calcium sulfate, CaS04> is used as a drying agent and sold under the trade name Drierite. For the reaction... 

It is necessary that the acetylene entering the reaction flask be of high purity. The acetylene purification train illustrated in Fig. 12 consists of three 500-ml. round-bottomed traps, each containing 250 ml. of concentrated sulfuric acid, followed by a 3-ft. column containing potassium hydroxide and a drying agent such as anhydrous calcium sulfate (Drierite). Empty flasks... 

For extraction of nonpolar analytes, drying agents are mixed with the matrix to adsorb moisture before extraction. Hydromatrix (Celite 566) has been used frequently. Sodium sulfate, and calcium sulfate (Drierite) are also used to dehydrate the matrix. Ratios of sample to drying agent of 1 1 up to 1 5 have been... 

Which drying agent is more efficient, Drierite or phosphorus pentoxide ... 

A range of experiments were set up that used active desiccant (310,000Bq/g), concrete (8,950 Bq/g) and metal (llOBq/g) as tritium emanating source materials. RO water, silica gel, cellulose filter paper, plastic, metal, and various desiccants were used as potential receivers. The interaction with drying agents such as silica gel, zeolites and Drierite (CaS04) were also examined. 

Some very good but specialized and reactive drying agents are potassium hydroxide, anhydrous potassium carbonate, sodium metal, calcium hydride, lithium aluminum hydride, and phosphorus pentoxide. Substances that are essentially neutral and unreactive and are widely used as drying agents include anhydrous calcium sulfate (Drierite), magnesium sulfate, molecular sieves, calcium chloride, and sodium sulfate. 

Drierite, a specially prepared form of Ccilcium sulfate, is a fast and effective drying agent. However, it is difficult to ascertain whether enough has been used. An indicating type of Drierite is impregnated with cobalt chloride, which turns from blue to red when it is saturated with water. This works well when gases are being dried, but it should not be used for liquid extractions because the cobalt chloride dissolves in many protonic solvents. 

Molecular sieves are sodium alumino-silicates (zeolites) that have well-defined pore sizes. The 4A size adsorbs water to the exclusion of almost all organic substances and is a fast and effective drying agent, but like Drierite it is impossible to ascertain by appearance whether enough has been used. MoleculcU sieves in the form of 1/16-in. pellets are often used to dry solvents by simply adding them to the container. 

Water, a common impurity, is often conveniently removed by placing the compound in a desiccator over a drying agent such as Drierite or by warming under reduced pressure. Distillation, either under reduced pressure or with steam, is often useful for separating the compound from the principal impurities. If the compound cannot be distilled easily, it is sometimes possible to convert it to a derivative which may be more easily distilled, such as in the conversion of an acid to an ester. The purified derivative may then be converted back to the original compound. 

The filter cake is broken up and returned to the same 5-1. flask. A saturated solution of sodium bicarbonate is added slowly (Note 7) with stirring until there is no further evidence of decomposition. The mixture is stirred for 2 hours longer. The solution is kept alkaline to litmus throughout by the addition of more sodium bicarbonate if necessary. The crude aldehyde is collected on an 8-in. Buchner funnel, washed with water, and allowed to dry as completely as possible. The product is dissolved in 1 1. of chloroform, the small aqueous layer is separated (Note 8), and the solution is dried with Drierite or another suitable drying agent. 

Dowex silicone fluid, 238, 241 Dowtherm A, 353, 699 Drierite, see Calcium sulfate, anhydrous Drying agents, 105-106,107, 353-354 Durene, 230, 426, 461, 674 Durenecarboxamide, 748 Durenecarboxylic add, 748 Durohydroquinone, 520 Duroic acid, 898 Duroquinone, 461, 520 Duryl 2,4-dimethyIphenol, 898 Dypnone, 24... 

Drying agents (which see) Calcium hydride. Calcium sulfate (Drierite). Cotton. Lithium aluminum hydride (see also Diglyme). Magnesium. Magnesium sulfate. Molecular sieves. Sodium sulfate. 

Drierite. Drierite, a commercially available brand of anhydrous calcium sulfate, has been around a long time and is a popular drying agent. You can put it in liquids and dry them or pack a drying tube... 

Use chunky dehydrating agents like anhydrous calcium sulfate (Drierite). Chunky drying agents have a much smaller surface area, so not much of the product gets absorbed. 

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