Dean and Stark receiver

Water content ASTM D-95 Determines the water content by distillation with a Dean and Stark receiver. 

Attach a Dean and Stark receiver for use with a heavy entrainer (Figure 5.1) and a reflux condenser. 

This is essentially a Dean and Stark tube (employed for determinations of moisture) but uncalibrated the capacity of this receiver is 7-5-10 ml. A tube calibrated in 0 -1 ml. may, of course, be employed, but for large classes the cheaper uncalibrated tube possesses obvious advantages. 

Water Determination. The sample is refluxed with toluene and the resultant toluene—water a2eotrope is distilled iato a gradual water-trap receiver (Dean and Stark apparatus). Here the water and toluene separate iato two distinct layers, permitting the volume of water to be read and its percentage calculated. 

Another test method that can be used, determination of the moisture content of moderately dry coal, can, in fact, be used for all coal samples that can be handled without appreciable loss of moisture. The principle of the method is that the coal is heated with an inert liquid that does not mix with water and which has a boiling point greater than that of water so that, on distillation, the water is carried over with the vapor from the liquid and, on condensation, separates from it in a graduated receiver. The Dean and Stark apparatus (Figure 3.1) or one of its many modifications can be used for this purpose. 

This is essentially a Dean and Stark" tube (employed for determinations of moisture) but uncalibrated the capacity of tliis receiver is pj 7 2. 

Toluene (99.8% anhydrous, water <0.001%, evaporation residue <0.005%) was purchased from Aldrich Chemical Company and used as received. The capacity of the receiver in the Dean-Stark trap was 28 mL. The initial amount of toluene placed in the flask was 88 mL. Upon heating to reflux, 28 mL of toluene was distilled from the flask and collected in the receiver. The remaining volume of toluene in the reaction flask was ca. 60 mL, corresponding to an approximately 0.50M concentration of the reactants. 

A mixture of tritylamine (13 g, 0.050 mol) and a freshly distilled aldehyde (0.055 mol) in benzene (50 mL) was heated to reflux in a Dean-Stark distillation device with a calibrated receiver. When the calculated amount of H20 (0.9 mL) had separated, the mixture was concentrated to give the product, which was recrystallized. For acetaldehyde imine 1 (R =Trt R2=Me) yield 100% mp 144-147°C (dec). 

Dialkyltin Compounds. All of the dialkyltin dimercaptides and dicarboxylates were prepared by reaction of the appropriate dialkyltin oxide (Alfa Inorganics) with the desired mercaptan or carboxylic acid. The reactions were carried out in refluxing benzene or toluene using a Dean-Stark water separator. The yields are quantitative and products require no purification (purity confirmed by H and 13C NMR). The dialkyltin dichlorides were obtained commercially (Alfa Inorganics) and used as received ... 

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