From the tar distillate, the chrysene can be fractionally precipitated, and the fluoranthene can be separated from most of the pyrene by fractional distillation in a partial vacuum.
On standing, the distillate separates into two layers, an aqueous and an oily layer, the oil floating on or sinking through the water according to its specific gravity.
For this purpose the crude distillate is redistilled over sulphuric acid and then fractionated.
The temperature of the interior of the chamber soon rises to more than the fusing-point of sulphur (113° C.), and the distillate accumulates at the bottom as a liquid, which is tapped off from time to time to be cast into the customary form of rods.
The distillate consists of a conglomerate of drops ("drop zinc").
ANTHRACENE (from the Greek civOpa, coal), C 14 H 10, a hydrocarbon obtained from the fraction of the coal-tar distillate boiling between 270° and 400° C. This high boiling fraction is allowed to stand for some days, when it partially solidifies.
The distillate is freed from vanadium by digestion with sodium amalgam.
- The general observation that under a constant pressure a pure substance boils at a constant temperature leads to the conclusion that the distillate which comes over while the thermometer records only a small variation is of practically constant composition.
The composition of the distillate is determinate (by Avogadro's law) if the molecular weights and vapour pressure of the components at the temperature of distillation be known.
If M 1, M2, and P 1, P 2 be the molecular weights and vapour pressures of the components A and B, then the ratio of A to B in the distillate is M 1 P 1 /M 2 P 2.
When distilling a mixture of partially miscible components a distillate of constant composition is obtained so long as two layers are present, i.e.
The first portion of the distillate brings over the gases dissolved in the water, ammonia and other volatile impurities, and is consequently rejected; scarcely two-fifths of the entire quantity of water can be safely used as pure distilled water.
It is manufactured by distilling wood in iron retorts at about 50o C., when an aqueous distillate, containing methyl alcohol, acetone, acetic acid and methyl acetic ester, is obtained.
The distillate is treated with anhydrous calcium chloride, the crystalline compound formed with the alcohol being separated and decomposed by redistilling with water.
At Denver and Ottawa the fuel used is " first distillate " oil, which is found to be cheaper than either naphtha or gas.
Obtained by fractional distillation of the aqueous distillate, special precautions being necessary owing to the excessively poisonous nature of the free acid: K 4 Fe(NC),±3H 2 SO 4 = 2K2S04+FeS04+6HCN.
The distillate was further purified by digestion with milk of lime, precipitation with water, and further digestion with calcium bromide and barium oxide, and was finally redistilled.
Three isomeric hydrocarbons of this formula exist; they occur in the light oil fraction of the coal: tar distillate, but they cannot be separated by fractional distillation owing to the closeness of their boiling points.
The peel is first softened by maceration; then a part of the softened peel is distilled with spirit and water, and the remainder is macerated in a portion of the distillate so obtained.
To interpret Christianity out of itself is one thing; to interpret it out of Luther, even out of a distillate of Luther, is possibly a lower thing.
They also investigated certain hydrocarbons occurring in the high boiling point fraction of the coal tar distillate and solved the constitution of phenanthrene.
The distillate obtained was diluted with one hundred volumes of ligroin (previously purified by shaking with fuming sulphuric acid) and then shaken for one or two hours with sulphuric acid (using ten volumes of acid to one volume of the distillate), the acid layer diluted with water, neutralized by lead carbonate and the lead salt again distilled with an equivalent quantity of ammonium chloride.
The distillate is finally rectified.
In commerce three brands of aniline are distinguished - aniline oil for blue, which is pure aniline; aniline oil for red, a mixture of equimolecular quantities of aniline and orthoand para-toluidines; and aniline oil for safranine, which contains aniline and ortho-toluidine, and is obtained from the distillate (echappes) of the fuchsine fusion.
In 1867 Rees Reece, taking advantage of the fact that two vapours of different boiling-points, when mixed, can be separated by means of fractional condensation, brought out an absorption machine in which the distillate was very nearly anhydrous.
DIPHENYL (phenyl benzene), CGH5.C6H5, a hydrocarbon found in that fraction of the coal-tar distillate boiling between 240-300° C., from which it may be obtained by warming with sulphuric acid, separating the acid layer and strongly cooling the undissolved oil.
The alkaloid is obtained from an aqueous extract of tobacco by distillation with slaked lime, the distillate being acidified with oxalic acid, concentrated to a syrup and decomposed by potash.
In order to obtain the phenol from this distillate, it is treated with caustic soda, which dissolves the phenol and its homologues tegether with a certain quantity of naphthalene and other hydrocarbons.
PYRENE, C16H10, a hydrocarbon found together with chrysene in the last portion of the coal tar distillate, and also in "Stupp" fat.
The crude solid product from the tar distillate is digested with carbon bisulphide to dissolve the pyrene, the solution filtered and the solvent evaporated.
The boiling point, being determined by the character of the constituents of the oil, necessarily varies greatly in different oils, as do the amounts of distillate obtained from them at specified temperatures.
This may be brought about by a distillation under pressure, or by allowing the condensed distillate to fall into the highly heated residue in the still.
PHENANTHRENE, C14H10, a hydrocarbon isomeric with anthracene, with which it occurs in the fraction of the coal tar distillate boiling between 270°-400° C. It may be separated from the anthracene oil by repeated fractional distillation, followed by fractional crystallization from alcohol (anthracene being the less soluble), and finally purified by oxidizing any residual anthracene with potassium bichromate and sulphuric acid (R.
The distillate is purified by treatment with lime and calcium chloride, and subsequent distillation.
Benzene is manufactured from the low-boiling fractions of the coal-tar distillate.
The light oil fraction of the coal-tar distillate, which comes over below 140° and consists principally of benzene, toluene and the xylenes, yields on fractionation (i) various volatile impurities such as carbon disulphide, (2) the benzene fraction boiling at about 80° C., (3) the toluene fraction boiling at too°, (4) the xylene fraction boiling at 140°.
Metallurgy The principles underlying the extraction of zinc may be summarized as: (I) the ore is first converted into zinc oxide; (2) the oxide is distilled with carbon and the distillate of metallic zinc condensed.
It may be purified by redistillation over barium and silver nitrates, followed by treatment of the distillate with a stream of ozonized air.
This is distilled to dryness and the distillate repeatedly recrystallized from cymene.
In order to separate the distillate into various fractions, and to remove as much of it as possible free from condensed steam, it is now usual to employ condensing appliances of special form with outlets for running off the different fractions.
Soc., 18 9 0, 5, p. 59 o), by distilling arsenious oxide with nitric acid and cooling the distillate, obtained a green liquid which consisted of nitrogen trioxide and peroxide in varying proportions, and concluded that the trioxide could not be obtained pure.
If a more dilute acid than this be distilled, water passes over in excess and the residue in the retort reaches the above composition and boiling point; on distillation of a stronger acid, excess of acid passes into the distillate and the boiling point rises until the values of the constant boiling mixture are reached.