BENZYL PHOSPHINES AND THEIR DERIVATIVES. 601 



products of the oxidation of the primary, secondary, and tertiary phosphines respectively ; 

 while, on concentrating the mother-liquors from the monobenzyl phosphinic acid, we 

 obtained a fourth, viz., monobenzyl phosphine, which we suspected to originate from a 

 fifth, namely, benzyl phosphinous acid, C 7 H 7 .P0 2 H. 2 . 



Fresh experiments were therefore necessary, not only to decide whether this latter 

 compound is really produced, but also to ascertain the quantities of the different 

 substances formed, the nature of the reactions which yield them, and the conditions under 

 which they are originated. 



Experiment 3.— Three quantities, each consisting of 50 grms. benzyl alcohol and 50 

 grms. of the phosphorus mixture (very carefully prepared with pure materials and 

 thoroughly free from bisulphide of carbon), were worked up as follows : — 



The weighed quantity of phosphorus mixture was placed in a flask of about 500 c.c. 

 capacity. The flask was then filled with carbonic anhydride, attached to an upright 

 condenser, and the benzyl alcohol allowed to drop from a tap funnel down the condenser. 

 Action occurred spontaneously as soon as some of the phosphorus mixture became 

 moistened with the alcohol, and at first violet vapours of free iodine appeared. It 

 seemed better to run in the alcohol in tolerably large quantities, so as to keep up a brisk 

 action, sufficient to cause rapid ebullition, but care had to be exercised, or the reaction 

 became unmanageable. When most of the alcohol had been added the reaction grew 

 sluggish, but was started afresh by shaking the flask, so as to thoroughly mix its 

 contents. 



In the case of two of the quantities the flasks were heated after all action was over, 

 but we think this was not advisable, as a sudden puff of hydriodic acid occurred. Always 

 towards the close of the reaction a little phosphonium iodide sublimed in the 

 condenser. 



The product in each case consisted of a dark brown resinous mass. About 300 c.c. 

 of cold water were next added to the contents of each flask and thoroughly incorporated 

 with them by shaking, when the mixture grew slightly warm. A current of steam was 

 next passed as long as oily liquid distilled over. By this means, from the three 

 quantities operated upon, 45 grms. of toluol were obtained boiling at 110°-i20°C. A 

 small quantity of a less volatile liquid remained above this temperature, but its amount 

 was trifling. Each of the products was steamed with three separate quantities of water, 

 so as to extract all soluble substances as thoroughly as possible. The residue was well 

 squeezed in a linen bag, and repeatedly digested with baryta solution as long as anything 

 was dissolved. For this purpose the mass was pounded in a mortar with hot baryta 

 solution, the extract decanted through a linen filter, and the operation repeated. Finally, 

 the residue was well squeezed in a linen filter, and next again and again boiled with 

 alcohol so long as anything was dissolved out. What remained undissolved consisted 

 apparently of amorphous phosphorus, and weighed 35 grms. 



The product of the reaction was thus split up into — 



(1) Aqueous extracts, containing hydriodic acid, monobenzyl phosphinic acid, some 



