Scientific American Supplement, No. 841, February 13, 1892Various
Science
Scientific American Supplement, No. 841, February 13, 1892
Various
Science -- Periodicals
As a general rule manufacturers employ a greater pressure than that
which was found necessary by the author. As a result, it appears from
these experiments that the wood not only loses incrusting matter, but
that part of the cellulose enters into solution. As a matter of fact,
the yield obtained in practical working from 100 parts of wood does
not exceed 30 to 35 per cent.--_Le Bull. Fab. Pap.; Chemical Trade
Journal._
* * * * *
NEW BORON COMPOUNDS.
An important paper is contributed by M. Moissan to the current number
of the _Comptes Rendus_, describing two interesting new compounds
containing boron, phosphorus, and iodine. A few months ago M. Moissan
succeeded in preparing the iodide of boron, a beautiful substance of
the composition BI_{3}, crystallizing from solution in carbon bisulphide
in pearly tables, which melt at 43 deg. to a liquid which boils
undecomposed at 210 deg.. When this substance is brought in contact with
fused phosphorus an intense action occurs, the whole mass inflames
with evolution of violet vapor of iodine. Red phosphorus also reacts
with incandescence when heated in the vapor of boron iodide. The
reaction may, however, be moderated by employing solutions of
phosphorus and boron iodide in dry carbon bisulphide. The two
solutions are mixed in a tube closed at one end, a little phosphorus
being in excess, and the tube is then sealed. No external application
of heat is necessary. At first the liquid is quite clear, but in a few
minutes a brown solid substance commences to separate, and in three
hours the reaction is complete. The substance is freed from carbon
bisulphide in a current of carbon dioxide, the last traces being
removed by means of the Sprengel pump. The compound thus obtained is a
deep red amorphous powder, readily capable of volatilization. It melts
between 190 deg. and 200 deg.. When heated _in vacuo_ it commences to
volatilize about 170 deg., and the vapor condenses in the cooler portion
of the tube in beautiful red crystals. Analyses of these crystals
agree perfectly with the formula BPI_{2}. Boron phospho-di-iodide is a
very hygroscopic substance, moisture rapidly decomposing it. In
contact with a large excess of water, yellow phosphorus is deposited,
and hydriodic, boric, and phosphorus acids formed in the solution. A
small quantity of phosphureted hydrogen also escapes. If a small
quantity of water is used, a larger deposit of yellow phosphorus is
formed, together with a considerable quantity of phosphonium iodide.
Strong nitric acid oxidizes boron phospho-di-iodide with
incandescence. Dilute nitric acid oxidizes it to phosphoric and boric
acids. It burns spontaneously in chlorine, forming boron chloride,
chloride of iodine, and pentachloride of phosphorus. When slightly
warmed in oxygen it inflames, the combustion being rendered very
beautiful by the fumes of boric and phosphoric anhydrides and the
violet vapors of iodine.
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