je prodsend It may we mitalled from ano wi then forms Vaguthu så reading of m. p. 220. It de mordanted fabrics red. 1900. Phloro glucod páratriozy-benzine, (1:3:51, results from the decompension of po oret n and querostin with potassic hydrate solution. mod by furing pedane o hydrate with gambøge, dragon's blood, moritanse neid, mil several cater bodies of this nature. It crystallises from wesome watery solution in rhombic prisms of the formula C,M,(011), 28,0 It lows all its crystal water at 100° and melts ** 228. It is soluble in water, alcohol, and ether, and gives a deep violet, coloration with ferric salts. The triacetate, C¿H2(Q.C2H2O)3, forms insoluble prisms.

On treatment with ammonia thin shining crystals of phloramine are produced, thus:

CH(OH) + NH,

H2O+CH2(NH2)(OH)2.

51

Nitrous weid forms a substance of the composition C12H ̧05, termed phlorein, which gives a deep purple solution with alkalies.

The following compounds of phloro-glucol have also been described:
Tribromide, CBra(OH)3.

Trinitro-phloro-glucol, Ca(NO2)3(OH)3.
Phloro-glucide, C12H10O5.

Tetrasubstitution Derivatives of Benzene.

1001. All three possible tetrachlor-benzenes are known. Symmetrical, (1:2:4:5), is obtained by the action of chlorine on benzene; it crystallises in needles, melts at 139°, and boils at 240°. Unsymmetrical, (1:3:4:5), obtained from ordinary trichlor-aniline, melts at 150° and boils at 246°.

Consecutive, (1:2:3:4), produced from consecutive trichlor-aniline, crystallises in needles, melts at 46°, and boils at 254°.

Unsymmetrical tetrabrom-benzene, (1:3:4:5), is obtained by the action of phosphoric bromide on ordinary tribrom-phenol or from ordinary tribrom-aniline; it forms long needles, melting at 98.5°.

Another modification of as yet undetermined constitution has been obtained by the action of bromine on benzene; it melts at 140°.

Tribrom-phenol, (1:2:4:6), obtained directly by the action of bromine on phenol, forms colourless needles, which melt at 95°.

Triiodo phenol, (1:2:4:6), obtained by the action of iodine and iodic acid on phenol, melts at 156°.

Two trichlor-anilines are known.

1:2:4:5, prepared by reducing the corresponding nitro-trichlorbenzene, forms colourless needles, melting at 96.5° and boiling at 270°. 1:2:4:6 is obtained by the action of chlorine on aniline; it crystallises in brilliant needles, melts at 77·5°, and boils at 260°. Tribrom-anilines, CH,Br3.NH2.

1:2:4:6, colourless needles, melting at 118°.

1:3:4:5 is crystalline, and appears to decompose below the temperature of fusion.

Trinitraniline, picramide, C6H2(NO2)3. NH2 (1:2:4:6), is obtained by the action of ammonia on trinitrochlor-benzene or on ethylic picrate. It forms dark green or violet crystals, which melt at 188°. The most important member of the group is

Trinitro-phenol, or Picric Acid, C6H2(NO2)3.OH (1:2:4:6).

1002. Trinitro-phenol is obtained by the action of excess of nitric acid (finally assisted by heat) on phenol, on paranitro-phenol, on both dinitro-phenols, also on indigo, aniline, and many resins. It is difficultly soluble in cold water, more readily in hot water, alcohol, and ether, and crystallises in brilliant pale yellow prisms and plates; it melts at 122° and explodes on stronger heating.

Its solutions dye silk and wool of a permanent yellow colour. Its taste is intensely bitter, and it behaves to metallic compounds like a strong acid (hence the name picric acid). The salts crystallise well, are of a deep yellow colour, and explode with great violence on heating or percussion. Potassic picrate, C6H2(NO2)3QK, forms needles difficultly soluble in water, whilst the sodic, ammonic, and baric salts are difficultly soluble.

Picric acid also yields peculiar crystallisable compounds with many

the ammonie air of permie ted sirnei, from which acetic acid „iberates the free acid is flauteramica-sheaoi, CENO, NHÀÒH, forming et needles of acid properties neiting at 1552.

In weens seulton, e her land. 4x moieenies of sulphurerted by imeen react in unmonic perate, Felting tamudo-nitrophemi, (ANG (N2, 95, salising in tars yellow needles or plates and melding wine comprands with ota wuis and bases.

By the action of “n and antrenoric acid in phenol, when heated, a crystalline stannons chlorite fontie sait separates, which, by decomposit on with sulphuretted hydrogen and evaporation of the filtrate, Fiends colourless needles of ramulo-gnenoi i perseturule :

readily winnie in water, fiffienitly in hyirenlerie wid, from which triamido-phenol cannot be parated unchanged. By mixing with sointion of ferric chloride yellowish brown needles with bush Instre separate of amido-kutriza-phenol hydrochloride, which dissolve with bluish colour in water. The reaction proceeds according to the equation:

CH2OH, NH,C1, + Fe,CI; = Fe.C1, + 4HC

3

+ CHOH (NH,CL

NH

NH

By slow addition of a hot solution of one part of pieric acid in nine parts of water to a wintion of two parts of potassie evanide in four parts of water heated to 60°, a red criour is developed, and on cooling brownish red scales of metallic green lustre separate of potassic picro cyamate or isopurpurate, C,H,KN;0, (comp. $922), which are little soinble in cold, but readily in hot water, and dissolve in alcohol with deep red colour, and in the dry state explode violently on heating. The free isopurpuric acid has not yet been obtained.

Penta Substitution Derivatives of Benzene.

1003. The chlorine and bromine compounds are known; they both crystallise in needies. Pentachlor-benzene, CHC1,. melts at 85° and boils at about 270°; pentabrom-benzene does not melt at 240°.

Trinitro-resorcin, CH(NO2)(OH), also known as oxypierie

acid or styphnic acid, is obtained by the action of cold nitric acid on resorcin, and from moritannic acid, many gum resins (e.g. galbanum, ammoniacum), also from the extracts of Brazil and Sapan woods by boiling with nitric acid. It crystallises in yellow hexagonal plates or prisms, melts at 175°, and can be sublimed by careful heating, but explodes on quick heating. It is difficultly soluble in water, readily in alcohol and ether, and behaves as a strong dibasic acid, whose salts, CH(NO2)3(OM), crystallise well and are explosive.

Tetrabrom-aniline, CHBr,.NH2 (1:2:3:4:6), is formed by the action of excess of bromine on metabrom-aniline, or on the dibromanilines, (1:2:4) or (1:3:6); it crystallises in needles, melting at 115.3°.

Hexa Substitution Derivatives of Benzene.

1004. Hexachlor-benzene, CC, also termed perchlor-benzene or Julin's chloride of carbon, is the last product of the action of chlorine on benzene, especially when assisted by antimonic chloride at the boiling temperature. It is obtained synthetically by passing the vapours of chloroform or tetrachlor-ethylene through red-hot tubes:

and from acetylene tetrachloride (§ 752) at 360° :

It crystallises in colourless prisms, melting at 222°-226° and boiling at about 330°.

Hexabrom-benzene is prepared by the action of bromine in presence of iodine on benzene. It resembles the chlor compound, but melts at above 310°, crystallises in needles, and can be sublimed.

Pentabrom-aniline, CBr,(NH2), is formed by the action of bromine on symmetric dibrom-aniline. It crystallises in transparent needles and does not melt at 222°.

Quinone and Hydroquinone Derivatives.

1005. Tetrachlor-quinone, or chloranil, CaClO2, is obtained, together with trichlor-quinone, by the chlorination of quinone, or still better by careful treatment of aniline, salicylic acid, or phenol with hydrochloric acid and potassic chlorate. It crystallises in brilliant yellow plates, readily soluble in boiling alcohol, which can be sublimed undecomposed, and is converted by phosphoric chloride into hexachlorbenzene.

Tetrachlor-quinone dissolves with purple-red colour. in hot potassic hydrate solution, and on cooling purple-red crystals of potassic chloranilate, CCl2O2(OK)2,H,O, separate, from which sulphuric acid liberates chloranilic acid, crystallising in reddish white scales of the formula CCl,O,(OH)2,H2O.

Sulphurous acid converts chloranil into tetrachlor-hydroquinone :

C¿CO2 + 2H2O + SO2 = H2SO4 + C¿C1(OH)2.

Chloranilic acid, on heating at 100° in closed vessels with sulphurous

acid, is converted into hydrochloranilic acid or dichlor-tetrahydroxybenzene:

C ̧€1,0 ̧(OH), + 2H ̧0 + 80, = H2SO ̧ + C ̧Cl2(OH),Hydrochloranilic acid crystallises in white needles; when exposed to air in a damp condition it is reconverted into chloranilic acid; with chloracetyl it yields a crystalline acetate, CgCl2(O.C2H2O), which melts unaltered at 235°.

1006. Tetrabrom-quinone, or bromanil, C,Br,O,, is obtained by adding 1 part of phenol to a mixture of 10 parts of bromine and 3 parts of iodine placed under water; after heating for two hours the crude product is extracted with carbonie disulphide, when bromanil remains undissolved. It crystallises in golden yellow plates and behaves similarly to chloranil.

1007. Tetrabrom-procatechin, C,Br,(OH),, is obtained by rubbing together pyrocatechin and excess of bromine; it crystallises in brownish red needles, insoluble in water.

Tribrom-pyrogate, C ̧Br,(OH),, is prepared from pyrogallul by action of bromine; it formus flat yellow-coloured needles, which dissolve in boiling water.