Melting point Fisher-Johns apparatus

Apparatus, melting point, Fisher-Johns or similar Balance, triple beam Beakers, 400 mL Brush, column Bulb, pipet Clamp, buret... [Pg.561]

The corrected melting point is 209.5-210.0°. Melting points were obtained with a Fisher-Johns apparatus. The recrystallized sample retained a pale tan shade... [Pg.55]

In order to determine the firing time of an expl, propint or pyro vs temp of heating, a few grains of sample are placed on die surface of preheated, and maintained at desired constant temperature, devices used for determination of melting point. One of such devices is Fisher-Johns Apparatus [described in Fisher Scientific Co, Pittsburgh ... [Pg.419]

Picrates. Melting points over 210° should not be taken of picrates in the usual liquid bath apparatus. Use a melting point bar such as the Dennis bar or a Fisher-Johns apparatus (Ref 88)... [Pg.433]

The Fisher-Johns apparatus (Fig. 50) is different in that you don t use capillary tubes to hold the sample. Instead, you sandwich your sample between two round microscope cover slides (thin windows of glass) on a heating block. This type of melting point apparatus is called a hot stage. It comes complete with spotlight. Look for the following. [Pg.106]

If your melting point apparatus uses capillary tubes to determine the melting point, an evacuated sealed tube is necessary, since caffeine sublimes the melting point is above the sublimation temperature (see Chapter 4). The melting point may be obtained using the Fisher-Johns apparatus without this precaution. [Pg.235]

Instruments Div. (Oak Brook, IL) Fisher-Johns melting point apparatus, Fisher Scientific Company (Pittsburgh,... [Pg.212]

The melting point seems to depend upon the rate of heating. Use of a Fisher-Johns melting-point apparatus gives a value of 240-242°. [Pg.79]

FIGURE 7.3 Fisher-Johns melting-point apparatus. (From Product Literature, Fisher Scientific, Springfield, NJ, 1997. With permission.)... [Pg.233]

Apparatus, melting point (like Fisher-Johns)... [Pg.532]

Figure ElO-2. A Fisher-Johns melting point apparatus.

Operating a Fisher-John s Melting Point Apparatus... [Pg.563]

Melting points were determined on Fisher-Johns melting point apparatus and are uncorrected. Rf values refer to TLC performed on Analtech Uniplates GF pre-coated with silica gel 60 to a thickness of 0.25 mm. The spots were... [Pg.384]

NOTE. It is suggested that a hot-stage melting point apparatus, such as the Fisher-Johns, be used due to the high melting point of the product. [Pg.272]

To a flask equipped with a stirrer and condenser is added a solution of 132gm (0.8 mole) of chloral hydrate in 125 ml of water. The solution is stirred at 70 -80°C while 12.6 gm (0.1 mole) of pure melamine is added. Within about 2 min the melamine is all dissolved, and a granular solid begins to precipitate. After heating for another 5 min the suspension is cooled, and the product is filtered, washed with water, and dried to afford 35.0 gm (83 o). Heating the product on a spatula causes it to decompose to chloral and melamine. However, a determination of the melting point on a Fisher-John melting point apparatus indicates it melts at 327°-329" C (see Table XII). The literature [72] reports that it melts with decomposition. [Pg.36]

Two basic methods are used for melting point determination. For the first method, a Fisher-Johns melting point apparatus as shown in Figure 13-1 is most commonly used. The apparatus consists of a rheostatically controlled heated block, a... [Pg.293]

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