53S Intelligence and Miscellaneous Articles. 



ACTION OF OXACIDS ON PYROXYLIC SPIRIT. 

 [Continued from page 429.] 



The oxacids, by their action in pyroxylic spirit, give rise to two 

 sorts of products : true neutral salts, corresponding to compound 

 tethers formed from alcohol j and true acid salts, corresponding to 

 sulphovinic or phosphovinic acid. The former are very easily ob- 

 tained, and all contain an atom of acid, an atom of methylene, and 

 one of water. They are more easily prepared, more stable and vo- 

 latile than the corresponding alcoholic compounds. The detailed ex- 

 amination of one of these compounds will show the theory of their 

 formation j the neutral sulphate of methylene, selected for this pur- 

 pose, has no corresponding compound in the alcohol series, at least 

 not so pure. 



Sulphate of mithylene. — Distil a mixture of one part of pyroxylic 

 spirit, with eight or ten parts of concentrated sulphuric acid. As 

 soon as ebullition commences, an oleaginous liquor distils, and when 

 it is over, this is found to be equal in quantity to the spirit employed ; 

 the distillation ought to be slow, but the boiling ought to be kept up. 



With the oleaginous liquid there distils an aqueous one $ the mix- 

 ture is to be agitated with a little water, and then with chloride of 

 calcium. It is then to be rectified from finely powdered caustic 

 barytes. Lastly, it is to be exposed to sulphuric acid and potash 

 in vacuo. 



These operations are to separate the sulphuric and sulphurous 

 acids and water • the only product which remains is colourless, has 

 an alliaceous smell, and its density is 1324. It boils at 360 Fahr. 

 without suffering any alteration. The density of its vapour is about 

 4-565. 



It is composed of 



1 atom of sulphuric acid. . 501*16 64*5 



1 atom of methylene 178-05 22-4 



] atom of water 112-50 13*1 100*0 



This neutral sulphate of methylene may not only be distilled with- 

 out alteration, but it does not decompose at 392° Fahr. It is slowly 

 decomposed by cold water, and very rapidly by boiling water, which 

 immediately destroys it with violent disengagement of heat j the 

 sulphate totally disappears without producing any new oil ; sulpho- 

 methylic acid is formed, and hydrate of methylene (pyroxylic spirit) 

 is reproduced. 



This compound has no action upon caustic barytes ; on the contrary, 

 hydrate of barytes and the hydrated alkalies in general decompose it 

 with the greatest facility : when, for example, a solution of potash is 

 mixed with it, much heat is excited ; the sulphate of methylene disap- 

 pears, and sulphomethylate of potash and pyroxylic spirit are pro- 

 duced in its place. In this reaction the water is found to reproduce 

 pyroxylic spirit. 



This decided action of the dissolved alkalies, as well as analysis, 

 prove a difference between the neutral sulphate of methylene and the 

 neutral sulphate of carbonated hydrogen of Serullas, which would 

 create surprise if it were not noticed : the former contains one atom 



