300 PROFESSOR LETTS ON PHOSPHORUS-BETAINES. 
drawn off and the phosphine collected in a separate vessel. The subjoined 
table gives statistics of the method. 
PREPARATION OF ZINC-ETHYL AND TRIETHYL-PHOSPHINE. 
Weight of Action began Action finished Zine Ethyl Phosphine 
Weight of Couple. Iodide of Ethyl. in— in— produced produced 
(1) 300 grms. | 300 germs. 50 mins. 15 mins. later. 95 grms. ) 
(2)'400°- 1 BBO" 5 Ape, int oalh food? iri (fisonte eemee 
(3) 300 __,, BOO) wats Le x 20 3 oye 2 ie 
(4) 200, 200 ,, 240 ,, 240 : G2 as, ) 
(5) 200 ,, 200° *;, 150". 65 A oO §; sony 
(6) 200 | 190 BBall Nid ber bens BO). 
(7) 200). 200. .,; oe 120 5 } 60 
(8) 200 ,, 200 2 days. — 3 ip \ boa 
(9) 400, 400.2», 30 mins. 15 ve to ys 
(10) 200 .,, 200 ox 40. 153 _ nee ore 
(11) 100 —,, 1 ara 20" 20 5 spe ptiee se 
(12) 400, | 400 , ap) | on eee aes | | Piece \ 
(13) 400 ,, 400 ,, ZT as aa, ee cea! 47 grms. 
(14) 400, AOONS, LOTS 60 iM HTS? <j, 40 ,, 
| (15) 300 ,, 800 __,, Sei os 90 s 250 pox SAL tes 
(16) 300, 5p) iit aie 120 % 8) sy | 53 
C7) S00- +3 Bo07 ty 2 ros 120 85 . Tei ss 
(18).500..;, 600,,.1,, Fiowe by 240 Bt TGOP Pees) 85 
(19) 350 ) 470 ”» 7 ”? 90 ” 117 » J a 
1442 A477 
It should be added, that although this method is undoubtedly the best we 
possess at present for preparing triethyl-phosphine, the yield of the latter is not 
very satisfactory, as it amounts to only about 50 per cent. of the calculated 
quantity. Moreover, the crude phosphine is by no means pure, and requires 
to be fractionally distilled many times before a product boiling at the right 
temperature is obtained. The higher boiling portions resulting from this 
fractionation consist mainly of oxide of triethyl-phosphine, but the nature of 
the lower boiling fractions (which amount to a considerable quantity) the author 
has not at present been able to ascertain. 
It ought also to be mentioned that triethyl-phosphine is a very disagreeable 
substance to work with for any length of time, as the constant inhalation of the 
small quantities of its vapour produces (as Hormann has remarked) sleepless- 
ness, which may continue for a considerable time. 
Although triethyl-phosphine oxidises at ordinary temperatures, it does not 
do so to any considerable extent so long as it is not heated. The author has 
always kept it in ordinary stoppered bottles, and has not adopted any special 
precautions while working with it. 
The author’s first experiments were made on the action of triethyl-phosphine 
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a 
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