Melting points apparatus

The electrically heated type of melting-point apparatus, which has certain advantages over the above types, is described on p. 6i, Fig 33-... 

Hold the tube horizontally and quickly seal this end in a micro-burner. Attach the tube (with the open end upwards) to a thermometer in the melting-point apparatus (Fig. i(c), p. 3) so that the trapped bubble of air in the capillary tube is below the surface of the bath-liquid. Now heat the bath, and take as the b.p. of the liquid that temperature at which the upper level of the bubble reaches the level of the surface of the batn liquid. 

Fig. 32). Using a fine pipette insert about i cm. length of the liquid into the bottom of the tube. Now place in the tube A a fine inverted melting-point tube B of about i mm. diameter, sealed at the upper end. Fasten the capillary tube to the ther- Fio. 32. mometer by means of a rubber band and place in a melting-point apparatus. Heat slowly until a stream of bubbles rises from the bottom... 

Fig. 11,10, 3, depicts a housing for the apparatus of Fig. 11,10, 2, a it is easily constructed from lengths of angle iron and asbestos board. If desired, torch bulbs may be fixed in the appropriate holders in the walls, and connected with a dry battery or accumulator in order to provide illumination of the melting point apparatus. The electric bulb immediately behind the apparatus should be connected to an inde pendent micro-switch. Alternatively,... 

This is the Reflected Light Melting Point Apparatus " marketed by Townson sind Harcar Ltd., Croydon, Englsind. 

A melting point test has been described for diazo compounds. The first 1 mm of a melting-point tube filled with c. 10 mg of test compound is inserted in a melting-point apparatus heated at 270°C. Once decomposition starts, the tube is removed. The decomposition rapidly propagates through the entire mass for unstable diazo compounds no such propagation is reported for stable versions. 

The submitters obtained 3.0 g. (78%) of product which melted at 99-100°. The melting point of 97-98° shown above was obtained by the checkers using a Tottoli melting point apparatus (Biichi) equipped with a 50° range Anschutz thermometer. A melting point of 98° has been reported ... 

The viscosity measurement was carried out using Brookfield Engineering Rheometer model HA DV-III equipped with small sample adapter, using spindle 28 and speed 10 rpm. Meanwhile, the melting point of the lipstick was observed with SMPI Melting Point Apparatus (Stuart Scientific). 

Melting points, measured in open capillary tubes using a Thomas-Hoover melting point apparatus, are uncorrected. Elemental analyses were performed by Galbraith Laboratories, Knoxville, Tennesee. % and 19C-NMR spectra were generally obtained with an IBM AF-100, if necessary the higher field Bruker WP-200 or AM-400 NMR spectrometer were employed. Chemical shifts are given in parts per million (ppm) on a a scale downfield from tetramethylsilane (TMS). Infrared spectra were recorded with a Perkln-Elmer 283 spectrophotometer. 

Melting Point Apparatus for Metals. Report UCRL-1056 (22. Dez. 1950). J. Amer. chem. Soc. 73, 3399 (1951)-... 

Sodium valproate does not melt, decompose, or physically change in the normal working range of the Thomas Hoover capillary melting point apparatus [5]. Valproic acid boils at 120-121 °C [2]. 

Fig. 3.4. Biichi Melting Point Apparatus. Biichi Melting Point Models B-540 and B-545 can determine melting points on routine and non-routine substances in research and quality control labs of pharmaceutical and chemical companies. Both models have a temperature range from ambient to 400°C and a selection of nine heating speeds. Heating (from 50 to 350°C) takes approximately 7 min and cooling (from 350 to 50°C) takes approximately 10 min. The units can simultaneously determine melting points of three samples or two...

There are al o several methods for the determination of the boiling point, with small amounts of substance, in the melting-point apparatus. 

A very elegant and simple method by which the molecular weight of organic substances can be determined in a melting point apparatus was recently described by K. East.1... 

Melting points were determined on a Thomas Hoover melting point apparatus or an Electrothermal melting point apparatus and are corrected. 

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