Abderhalden


The Abderhalden design, employed at some French distilleries and used in the United Kingdom for distilling tar to a base-tar residue, is probably the simplest single-pass, atmospheric-pressure design (7). After straining and the addition of alkaU as a corrosion inhibitor, the cmde tar is heat-exchanged with the distillation side-streams and the hot pitch and then passed through an economizer coil in the convection section of the furnace. This furnace is essentially a rectangular chamber lined with refractory brick divided into two sections by a curtain wall, which has apertures to enable the hot flue gases to pass from one compartment to the other. The first section serves as the combustion and radiant-heating section in which coke-oven gas, fuel oil, or creosote-pitch fuel is burned at specially designed nozzles projecting into the chamber. The products of combustion are drawn by a fan from the combustion chamber into the second, or convection, chamber before exhaustion to a chimney stack via a waste-heat coil. The coils through which the tar is pumped are, in some designs, set in the walls of the convection chamber only. In other designs, the main heating coil is partly set in the combustion chamber where it is heated by direct radiation.  [c.336]

Where substances are sufficiently stable, removal of solvent from recrystallised materials presents no problems. The crystals, after filtering at the pump (and perhaps air-drying by suction), are heated in an oven above the boiling point of the solvent (but below this melting point of the crystals), followed by cooling in a desiccator. Where this treatment is inadvisable, it is still often possible to heat to a lower temperature under reduced pressure, for example in an Abderhalden pistol. This device consists of a small chamber which is heated externally by the vapour of a boiling solvent. Inside this chamber, which can be evacuated by a water pump or some other vacuum pump, is  [c.25]

Methods for removing water from solids depends on the thermal stability of the solids or the time available. The safest way is to dry in a vacuum desiccator over concentrated sulfuric acid, phosphorus pentoxide, silica gel, calcium chloride, or some other desiccant. Where substances are stable in air and melt above 100°, drying in an air oven may be adequate. In other cases, use of an Abderhalden pistol may be satisfactory.  [c.26]

Bis-(chloromethyl)durene [3022-16-0] M 231.2, m 197-198 . Crystd three times from benzene, then dried under vacuum in an Abderhalden pistol.  [c.134]

Naphthylamine [134-32-7] M 143.2, m 50.8-51.2 , b 160 , pK 3.94. Sublimed at 120° in a stream of nitrogen, then crystd from pet ether (b 60-80°), or abs EtOH then diethyl ether. Dried under vacuum in an Abderhalden pistol. Has also been purified by crystn of its hydrochloride from water, followed by liberation of the free base and distn finally purified by zone melting. CARCINOGEN.  [c.306]

Naphthylamine [91-59-8] M 143.2, m 113 , pK 4.20. Sublimed at 180° in a stream of nitrogen. Crystd from hot water (charcoal) or benzene. Dried under vacuum in an Abderhalden pistol. CARCINOGEN.  [c.306]

A -Phenyl-l-naphthylamine [90-30-2] M 219.3, m 63.7-64.0°, pK j, -0.1. Crystd from EtOH, pet ether or benzene/EtOH. Dried under vacuum in an Abderhalden pistol.  [c.331]

Abderhalden pistol. [Das et al. J Chem Soc, Faraday Trans I 78 3485 1982.] HIGHLY POISONOUS and potentially explosive.  [c.466]

A solid insensitive to air is easily dried by spreading the material over a large piece of filter paper and allowing moisture or solvent to evaporate. However, many organic solids are sensitive to air or moisture and must be dried under reduced pressure in a vacuum desiccator or vacuum oven. Moreover, complete drying of a sample to be analyzed by combustion analysis necessitates vacuum drying. For vacuum drying of small samples, an Abderhalden (drying pistol) is a convenient arrangement (Fig. A3.18).  [c.183]

In the Abderhalden plant, the cmde tar leaves the waste-heat coil at ca 150°C under a back pressure and is expanded into the dehydrator. The temperature in this cylindrical baffled vessel is maintained by circulating hot, dehydrated tar through a coil at the base. The moisture and light oils flash off and pass directly to the side-stream fractionating column. The dehydrated tar from the base of the dehydrator is pumped at 400—500 kPa (ca 4—5 amt) through the main heating coil in the radiant section of the furnace. The hot tar at 350—360°C is injected into the pitch flash chamber together with superheated steam. Steam and oil vapors join the dehydrator overhead distillate at the base of the fractionation column, from which an overhead stream of water and light oils, side-stream oil fractions, and a heavy oil residue are taken. The overhead stream is separated in a decantor and the oil layer partly returned to the bubble-cap fractionating column for reflux. A similar design differs only in the extent of heat exchange (8).  [c.336]

Methoxynaphthalene [93-04-9] M 158.2, m 73.0-73.6°, b 273°/760mm. Fractionally distd under vacuum. Crystd from absolute EtOH, aqueous EtOH, benzene or n-heptane, and dried under vacuum in an Abderhalden pistol or distd in vacuo. [Kikuchi et al. J Phys Chem 91 574 1987.]  [c.286]

Methylnaphthalene [91-57-6] M 142.2, m 34.7-34.9 , b 129-130 /25mm. Fractionally crystd repeatedly from its melt, then fractionally distd under reduced pressure. Crystd from benzene and dried under vacuum in an Abderhalden pistol. Purified via its picrate (m 114-115°) as described for 1-methylnaphthalene.  [c.295]

Nitrophenol [88-75-5] M 139.1, m 44.5-45.5 , pK 7.23. Crystd from EtOH/water, water, EtOH, benzene or MeOH/pet ether (b 70-90°). Can be steam distd. Petrucci and Weygandt [Anal Chem 33 275 1961] crystd from hot water (twice), then EtOH (twice), followed by fractional crystn from the melt (twice), drying over CaCl2 in a vacuum desiccator and then in an Abderhalden drying pistol.  [c.312]

Phenylanisole (4-methoxybiphenyl) [361-37-6] M 184.2, m 89.9-90.1". Crystd from benzene/pet ether. Dried under vacuum in an Abderhalden pistol.  [c.327]

V,/V,/V, /V -Tetramethylbenzidine [366-29-0] M 240.4, m 195.4-195.6°, pKEst(i) 3.4, pKesi(2) 4.5. Crystd from EtOH or pet ether, then from pet ether/ benzene, and sublimed in a vacuum. [Guarr et al. J Am Chem Soc 107 5104 1985.] Dried under vac in an Abderhalden pistol, or carefully on a vacuum line.  [c.363]

Tetramethylcyclobutan-l,3-dione [933-52-8] M 140.2, m 114.5-114.9°. Crystd from benzene and dried under vacuum over P2O5 in an Abderhalden pistol.  [c.363]

Cyclopropyltriphenylphosphonium Bromide (5). The lactone salt is pyrolyzed by placing it in a round-bottom flask fitted with an adaptor attached to a vacuum source (aspirator is sufficient). The flask is heated (oil bath) to 180-190° for 48 hours. The residue is a virtual quantitative yield of the tan product, which may be crystallized from ethyl acetate giving cream crystals, mp 189-190°. An alternate setup is convenient if a drying pistol (Abderhalden) is available. The compound is placed in the pistol, which is then evacuated. Decalin (bp approx. 187°) is refluxed over the pistol to provide the heating source. The work-up is the same.  [c.109]


See pages that mention the term Abderhalden : [c.139]    [c.82]    [c.26]    [c.103]    [c.121]    [c.304]    [c.324]    [c.35]    [c.44]    [c.380]    [c.439]   
Advanced organic synthesis (1971) -- [ c.183 ]