Two hundred and fifty grms. chloride of sulphur are added to 100 grms. glycol boiling at 196-198° contained in a dry round-bottomed flask of about -litre capacity, and the mixture is heated on the water-bath with a reflux condenser until the evolution of hydrochloric acid ceases, an operation which requires three or four days. After cooling, the contents of the flask are extracted several times with ether, which readily dissolves out the chlorhydrin and the ethereal solution is decanted from precipitated sulphur. It is shaken for a time with moist potassium carbonate. The ether is then distilled off on the water-bath, and the distillation continued over a lamp. The portion, which passes over at 128-131°, is nearly pure ethylene chlorhydrin.

Cl

2CH(OH)2 + 2S,Cl2 = 2C2H4OH 2C2H4OH + 2HCI + 3S + SO2 Glycol Chloride of Sulphur Ethylene Chlorhydrin.

Properties.-Colourless liquid; b. p. 130-131°; sp. gr. 1 24 at 8°.

litre capacity connected with a receiver furnished with an exit tube. Into the melted sulphur, chlorine, dried by passing through conc. sulphuric acid and fused calcium chloride, is conducted, and chloride of sulphur distils over (Fig. 25). When the greater portion of the sulphur has been converted into chloride the evolution of gas is stopped. In the receiver a brownish yellow liquid collects, and is redistilled. The portion passing over at 138°-139° is pure chloride of sulphur.

1.68.

Properties.-A reddish-yellow liquid; b. p. 139°; sp. gr. Fumes in the air, and decomposes with water into sulphurous acid, hydrochloric acid, and water. This liquid is best preserved in sealed vessels.

PREPARATION LIII.

SUCCINIC ACID, C4H6O4 = COOH.CH2CH2COOH. (Ethylenedicarboxylic Acid.)

LITERATURE.-Simpson (1860), Proc. Roy. Soc. 10, 574; Geuther (1861), Ann. Ch. Pharm. 120, 268.

100 grms. ethylene bromide,

One hundred grms. ethylene bromide and 75 grms. potassium cyanide in alcoholic solution are heated together on the water-bath in a round-bottomed flask of about 2-litre capacity connected with reflux condenser. This process is continued until the potassium cyanide is converted into bromide, which separates out from the solution. To the alcoholic solution, filtered from potassium bromide, the calculated quantity of caustic potash (about 70 grms.) is added, and the mixture is heated on the water-bath with an upright condenser until the strong evolution of ammonia gas begins to slacken. The cooled contents of the flask are acidified with dilute hydrochloric acid and carefully evaporated to dryness. The dry powdered residue is extracted several times with absolute alcohol. On distilling off the alcohol the succinic acid remains behind in small crystals. The product, which is slightly coloured, is re-crystal

lised from hot water (with the addition, if necessary, of animal charcoal) and, on cooling, forms colourless crystals.

CH4Br2+ 2KCN =

Ethylene Bromide.

C2H4(CN)2 + 2KBr
Ethylene Cyanide.

C2H4(CN)2 + 2KOH + 2H2O = C2H1(COOK), + 2NH3

Potassium Succinate.

C2H1(COOK), + 2HCl = C2H4fCOOH)2 + 2KCI

Succinic Acid.

Properties.-Colourless prisms which sublime above 100° without decomposition; m. p. 180°; at 235° the acid decomposes forming the anhydride; soluble in water, alcohol, and ether; insoluble in chloroform.

PREPARATION LIV.

DIBROMSUCCINIC ACID, CH,Br2O4

COOH.CHBr.CH Br. COOH.

=

LITERATURE.-Kekulé (1861), Ann. Ch. Pharm. 117, 120 and (1861) Spt. 1, 351; Burgoin (1873), Bull. Soc. Chem. 19, 148.

Twelve grms. succinic acid, 32 grms. bromine, and 12 grms. water are heated in a sealed tube with capillary end, on the air-bath, for six hours at 170°

(Fig. 26). On cooling, the tube is opened by wrapping it tightly in a cloth and softening the capillary end

FIG. 27.

The red colour of the bromine has completely disappeared, and the tube is filled with a solid greyish white mass. By recrystallising the product from