Word Finder - distillation

definition

The act of falling in drops, or the act of pouring out in drops.

definition

That which falls in drops.

definition

(chemical engineering) The separation of more volatile parts of a substance from less volatile ones by evaporation and condensation.

definition

The substance extracted by distilling.

They may be prepared by the dry distillation of the ammonium salts.

Notwithstanding the inconsistency of his allocation of substances to the different groups (for instance, acetic acid was placed in the vegetable class, while the acetates and the products of their dry distillation, acetone, &c., were placed in the mineral class), this classification came into favour.

The metal is usually obtained from the flue-dust (produced during the first three or four hours working of a zinc distillation) which is collected in the sheet iron cones or adapters of the zinc retorts.

Under such conditions, distillation takes place at higher temperatures than the normal boiling-points of the constituent hydrocarbons of the oil, and a partial cracking results.

This subject is treated in the article Solution; for the properties of liquid mixtures reference should also be made to the article Distillation.

They may be separated by fractional distillation.

The distillate is purified by treatment with lime and calcium chloride, and subsequent distillation.

The ore, even if it is not blende, must be roasted or calcined in order to remove all volatile components as completely as possible, because these, if allowed to remain, would carry away a large proportion of the zinc vapour during the distillation.

On dry distillation it is resolved into trimethylamine and methyl alcohol.

If the substance operated upon be practically pure to start with, or the product of distillation be nearly of constant composition, the operation is termed "purification by distillation" or "rectification"; the latter term is particularly used in the spirit industry.

This variation is termed "distillation under reduced pressure or in a vacuum."

The vaporization of a substance below its normal boiling-point can also be effected by blowing in steam or some other vapour; this operation is termed "distillation with steam."

Distillation appears to have been practised at very remote times.

The second liquid product of the destructive distillation of coal is the ammoniacal or gas liquor, which consists of water containing ammonia salts in solution, partly condensed from the hot gas, and partly added to wash the gas in the scrubbers.

The gas which is obtained by the destructive distillation of coal, and which we employ as our chief illuminant, is not a definite com pound, but a mechanical mixture of several gases, some Gaseous .

Petroleum spirit is tested for specific gravity, range of boilingpoints, and results of fractional distillation.

If a complex mixture be operated upon, and a separation effected by collecting the distillates in several portions, the operation is termed "fractional distillation."

The Alexandrians prepared oil of turpentine by distilling pine-resin; Zosimus of Panopolis, a voluminous writer of the 5th century A.D., speaks of the distillation of a "divine water" or "panacea" (probably from the complex mixture of calcium polysulphides, thiosulphate, &c., and free sulphur, which is obtained by boiling sulphur with lime and water) and advises "the efficient luting of the apparatus, for otherwise the valuable properties would be lost."

The Arabians greatly improved the earlier apparatus, naming one form the alembic; they discovered many ethereal oils by distilling plants and plant juices, alcohol by the distillation of wine, and also distilled water.

The apparatus differs very slightly from that employed in ordinary distillation.

The main objection to the Hempel is the retention of liquid in the beads, and the consequent inapplicability to the distillation of small quantities.

On this fact depends "rectification or purification by distillation."

In this we have the theory of "distillation under reduced pressure."

The theory of fractional distillation, or the behaviour of liquid mixtures when heated to their boiling-points, is more complex.

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.

These con-, ditions pertain in cases where distillation with steam is successfully practised, the relatively high volatility of water being counterbalanced by the relatively high molecular weight of the other component; for example, in the case of nitrobenzene and water the ratio is I to 5.

As the distillation proceeded one layer would diminish more rapidly than the other until only the latter would remain; this would then distil as a completely miscible mixture.

The distillation of completely miscible mixtures is the most common practically and the most complex theoretically.

At one time it was thought that these mixtures of constant boiling-point (an extended list is given in Young's Fractional Distillation) were definite compounds.

When the substance operated upon is of uncertain composition, as, for example, coal, wood, coal-tar, &c., the term destructive distillation is employed.

Dry distillation is extremely wasteful even when definite substances or mixtures, such as calcium acetate which yields acetone, are dealt with, valueless by-products being obtained and the condensate usually requiring much purification.

For the distillation of liquids the retort is usually a cylindrical pot placed vertically; cast iron is generally employed, in which case the bottom is frequently incurved and thicker than the sides in order to take up the additional wear and tear.

Glass stills heated by a sand bath are sometimes employed in the final distillation of sulphuric acid; platinum, and an alloy of platinum and iridium with a lining of gold rolled on (a discovery due to Heraeus), are used for the same purpose.

The simple distillation of sea-water, and the production thereby of a certain proportion of chemically fresh water, is a very simple problem; but it is found that water which is merely evaporated and recondensed has a very disagreeable flat taste, and it is only after long exposure to pure atmospheric air, with continued agitation, or repeated pouring from one vessel to another, that it becomes sufficiently aerated to lose its unpleasant taste and smell and become drinkable.

The technology of distillation is best studied in relation to the several industries in which it is employed; reference should be made to the articles COAL-TAR, GAS, PETROLEUM, SPIRITS, NITRIC ACID, &c. (C. E.*)

By electrolysing an aqueous solution of the chloride with a mercury cathode, a liquid and a solid amalgam, SrHgn, are obtained; the latter on heating gives a mixture of Sr 2 Hg 5 and SrHg 5, and on distillation an amalgam passes over, and not the metal.

This water cannot be entirely removed by fractional distillation, and to prepare anhydrous or "absolute" alcohol the commercial product must be allowed to stand over some dehydrating agent, such as caustic lime, baryta, anhydrous copper sulphate, &c., and then distilled.

They are both obtained by passing chlorine over tellurium, the product being separated by distillation (the tetrachloride is the less volatile).

Amorphous carbon is obtained by the destructive distillation of many carbon compounds, the various kinds differing very greatly as regards physical characters and purity, according to the substance used for their preparation.

When the distillation is finished the iron box, after cooling, is unclamped and the product turned out beneath the surface of paraffin.

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.

The alcohol is removed by distillation in vacuo, and by further concentration in vacuo a solution may be obtained which evolves 580 volumes of oxygen.

It is also formed in the destructive distillation of many substances, as wood, coal, caoutchouc, bones, resin and the fixed oils.

The chief consideration here is that the stable form must have the lower vapour pressure, otherwise, by distillation, it would transform in opposite sense.

On dry distillation they yield nitriles and ammonia.

The potato is largely cultivated, not merely for food, but for distillation into spirits.

The hydrocarbons are separated from the "Stupp" by means of alcohol, the soluble portion on distillation giving first phenanthrene and then a mixture of pyrene and fluoranthene.

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.

Distillation of its calcium salt gives benzophenone with small quantities of other substances, but if the calcium salt be mixed with calcium formate and the mixture distilled, benzaldehyde is produced.

The valuation of pyrolusite is generally carried out by means of a distillation with hydrochloric acid, the liberated chlorine passing through a solution of potassium iodide, and the amount of iodine liberated being ascertained by means of a standard solution of sodium thiosulphate.