520 Royal Society, 



The acid contained — 



Sulphur 4r3 per cent. Theory requires 4'1\ per cent. 



Thiacetic acid is also formed in small quantity and by secondary 

 action, by distilling pentasulphide of phosphorus with fused acetate 

 of soda. Pentachloride of phosphorus gives a violent reaction with 

 thiacetic acid, yielding sulphochloride of phosphorus, chloride of 

 othyle, and hydrochloric acid, 



^* h' ^ } S + PC^=C« H3 O Cl+H Cl + P S CI'. 

 Thiacetate of Othyle. — Sulphide of Othyle. — Anhydrous Sulphuretted 

 Acetic Acid. — Pentasulphide of phosphorus acts but very feebly upon 

 anhydrous acetic acid in the cold, but on heating a violent reaction 

 takes place. By distilling the product, the anhydrous acid is obtained 

 in the form of a colourless liquid, boiling at about 121" C, and having 

 an odour greatly resembling sulphuretted acetic acid. On mixing 

 with water it falls to the bottom, without, at first, suffering any 

 change ; on standing, however, it is slowly dissolved and decom- 

 posed into sulphuretted acetic acid and ordinary acetic acid. This 

 change takes place much more rapidly on heating, 



C^H^OT H-) ^_C^H501 ^ C-^H3 01 Q 



It appears that anhydrous sulphuretted acetic acid is also pro- 

 duced by acting on the othyle-sulphide of lead with chloride of othyle, 

 at all events chloride of lead is formed. Chloride of benzoyle gives 

 with the lead salt a similar reaction, and it is probable that an inter- 

 mediate sulphuretted acid is formed, having the formula 



C'^ H^ O \ c; 

 C^HiQ/*- 



Thiacetate of Othyle. — Sulphuretted Acetic ^ther. — This compound 

 may be prepared by the action of pentasulphide of phosphorus on 

 acetic jether. It is a liquid lighter than water, and possesses an 

 odour resembling acetic aether and sulphuretted hydrogen. It boils 

 at about 80° C. 



It will be seen that the action of tersulphide and pentasulphide of 

 phosphorus above described produces sulphuretted organic com- 

 pounds by substituting sulphur for oxygen. The compounds ob- 

 tained in this way may also be formed by replacing one or two 

 atoms of hydrogen in sulphuretted hydi^ogen (H- S), or one or two 

 atoms of metal in sulphide of potassium (K- S), or in sulphide of 

 hydrogen and potassium (KHS), by organic radicals. Mercaptan, 

 and the sulphides of alcohol radicals have, in fact, been long ob- 

 tained in this manner. 



The formation of a sulphuretted compound containing an acid 

 radical has been observed by Gerhardt by acting on sulphide of 

 lead with chloride of othyle. I have not made many experiments of 

 this kind, but I have observed that chloride of benzoyle is not de- 

 composed by sulphuretted hydrogen, while it (as well as chloride of 

 othyle) gives a reaction with sulphide of iiydrogen and potassium 

 yielding chloride of potassium. 



