Aug., 1939
NOTES
The mixture was then brought to boiling and live steam passed through it until the total volume of distillate was 250 ml. The steam distillate wa5 extracted with two 75-ml. portions of ether and the ethereal extract dried over sodium sulfate. The ether was removed on the steam-bath and the residue vacuum-distilled: yield of phenylacetaldehyde, h. p. 87-8Ro (18 mm.), 5.4 g., 0.045 mole, 33%. The other aldehydes studied were prepared by much the same procedure. The results are summarized in the table. Time allowed lor pptn. of nddn. Aldehyde prepared
Benzaldehyde' p-Naphthaldehyde6 p-Tolualdehyde' Phenylacetaldehyde' Isccapraldehyde o-Tolualdehyde',8 e-Naphthaldehyde' 8-Hydroiypropionaldehyde'
COmpleX
Yield, %
5 hours
12 hours 12 hours 18 hours 7 days 8 days 7 days 7 days
97 91 77 33 31 9 7
n
(4) Reported by Stephen' in almost quantitative yields. (6) Oor l i t e r of hot w ~ f WPO ~ r added t o the residue and live steam pessed through the mixture as Iomr as any solid came over in the rtcam distillate. T h e solid was rceryrtollizcd from 50% aqueous alcohol. I'ulton and Robinson. 3. Chrm. SOL., 161. 200 ( l ! M l ) , reported the preparation of E-nsphthaldehyde hy the Stcphcn technique in 75% yield. Their work was published after the ~ r e i ' a ration had been eomplefed at the llnivcraify of Mcwyland. (6) Rcmovnl 01 the aldehyde by stcam distillntian was not sftcmptcd; 600 ml. of water was added to the addition complex, the mixture warmed on the steam-hsfh lor one hour. allowed 10 cool and extracted with ether. The product was n thick. tarry liquid which gave ncgrtive tcLr with Schiff and Tollcnr reagents. (71 Reported by Stephen' in poor yield. (8) Thcrc was ne precipitate after x v e n day- so one-half of the ether was removed and the reaction mixture allowecl t o stand Y O O ~ I ~ C T twenty-lour hours.
2240
and slowly cooled the white powder. In our experiments, a cellophane membrane was tied over the mouth of a test-tube (an open tube could of course be used) containing a 1% solution of NE+HPOl and the tube inverted in a slightly acidified 0.2% solution of Ph(GH3O2).3H20. A t once an almost amorphous precipitate of lead orthophosphate appeared on the under side of the membrane and in about a minute crystals of the white salt started to fall. The crystals (some of which were 2 mm. in length) were uniaxial hexagonal prisms exhibiting strong birefringence and showing an optically negative character. The values of w = 1.970 and e = 1.936 check the data in the literature for the refractive indices of lead orthophosphate. Analysis of the crystals gave a value of 17.4% as compared with the calculated value of 17.5% for PbdPOh.
CHEM~STRY LARORATORY UNIVERSITY OF MARYLAND COLLEGEPARK, MD. RECEIYED A P R ~ I14, . 1939
Crystalline Lead Orthophosphate BY EDWARD J. ROEHL
Fig. 1.
In the preparation of crystalline metathetical The accompanying photomicrograph a t (50 X) reaction products where the solubility of the reshows some of the crystals obtained. action product is very low, it is often difficult to LABORATORY obtain crystals large enough for microscopic ex- RESEARCH INTERNATIONAL NICKEL Co. amination, and a number of methods have been RAYONNII.NEWJERSEY RECEIVED APR~L 14, 1939 employed for maintaining the necessary slight supersaturation. The writer has successfully furfuryl Bromide (2-Bromomethylfuran) employed a cellophane membrane for a number of BY J. E. ZANETTIAND J. T. BASHOUR such cases. By treating a solution of lead acetate with soIn 1927 one of us' prepared an ether solution of dium hydrophosphate, Aiders and Stahler' suc- a-furfuryl bromide by acting on furfuryl alcohol ceeded in preparing lead orthophosphate, but with phosphorus tribromide. The solution proved without any signs of microscopically recognizable satisfactory in the synthesis of various furfuryl crystals. In fact, i t appears from the literature ethers but the pure bromide was not separated that the only method of preparing this salt is the as its decomposition was rapid once the solvent rather cumbersome one of Zambonini,2who fused was evaporated. Von Braun and Kohler* had (1) A i d m and Stahler. Em.. 4% 2263 (1909). (2) Zsmhooini. 2. KwsI., 68, 226 (1923).
(1) Znaetti. THISJ o m w r ~49, . 1005 (1827). (1) Von Braun and Kohlrr. Be,., OIB, 86 (1918).
