322 



SCIENCE 



[N. S. Vol. LII. No. 1344 



has recently attracted considerable attention be- 

 cause of the fact that it is obtained in rather 

 large quantity as a by-product in the spruce pulp 

 industry. Thymol, which is of considerable com- 

 mercial importance and which bears the same re- 

 lation to p-cymene as does phenol to benzene, can 

 not be obtained from p-oymene by the ordinary 

 methods of getting a phenol from its correspond- 

 ing hydrocarbon. However, by using the follow- 

 ing rather indirect method the synthesis of thymol 

 was accomplished: p-cymene was nitrated and the 

 compound with the nitro group in the position 

 ortho to the methyl group was obtained. This 

 compound was reduced to the corresponding amino 

 p-cymene or cymidine, which when sulphonated 

 gave cymidine sulphonic acid, the sulphonic group 

 entering the position ortho to the isopropyl group. 

 The amino group of cymidine sulphonic acid was 

 then removed through diazotization and subse- 

 quent reduction with alcohol and copper powder. 

 The cymene sulphonic acid thus obtained was con- 

 verted into its sodium salt and the latter when 

 fused with sodium hydroxide was converted into 

 thymol. 



The vapor pressure of phthalic anhydride: K. P. 



MONEOE. 



The prepatration of furfural: K. P. Monroe. 

 Corn-cob adhesive prepared according to the 

 method of La Forge and Hudson (J. Ind. Eng. 

 Chew,., 10 (1918, 925) by extracting corn-cobs 

 with water under pressure at 150° 0. is an excel- 

 lent source for furfural, since the gums so ob- 

 tained are rich in pentosan and yield 26 per cent. 

 of pure furfural. The essential improvements over 

 the previously published methods of obtaining fur- 

 fural from pentosan containing material are (1) 

 removal of furfural from the reaction mixture by 

 a rapid current of steam during the hydrolysis by 

 25 per cent. H-SO,; (2) separation of furfural 

 from the dilute aqueous solution which constitutes 

 the distillate by distillation with the acid of a 

 fractionating column. Uses for furfural in the 

 industries and arts are outlined; among these are 

 the preparation of: hard resins similar to the 

 well-known "Bakelite," soluble resins which may 

 find application in the varnish trade, a series of 

 dyes which may be obtained by condensation with 

 various coal-tar products. 



The vapor pressure of phthalic anhydride: K. P. 

 MONKOE. The vapor pressure of phthalic anhy- 

 dride was determined by the static isoteniscope 

 method of Smith and Menzies {J. Am. Chem. Soc, 

 32 (1910), 1412-59). The following equation, of 



the type obtained by integration of the Clausius- 

 Clapeyron equation with simplifying assumptions, 

 was found to express the results: 



2S23.5 

 T 



(1) 



logio p = 7.94234 ■ 



where p = vapor pressure in millimeters of mer- 

 cury and T = absolute temperature. The molar 

 latent heat of vaporization was calculated to be 

 12,910 colories, while the value 18.6 was obtained 

 for the entropy of vaporization divided by 22 (the 

 gas constant) at the temperature (near 218°) at 

 which the concentration of vapor is 0.00507 mole 

 per liter. According to the criterion of Hilde- 

 braud {J. Am. Chem. Soc., 37 (1915), 970), this 

 indicates phthalic anhydride to be a normal liquid. 



The present independence of American synthetic 

 dyes and hoiv it was accomplished: Bobekt E. 

 HussET. Prior to the war all of the biological 

 dyestuffs used in the bacteriological laboratories 

 and in the laboratories of public health came from 

 Germany. The two chief difficulties upon the ces- 

 sation of imports that confronted the American 

 manufacturer were lack of raw supplies and lack 

 of accurate information as to their manufacture. 

 All of these dyes must be absolutely uniform and 

 standardized as certain arbitrary amounts are used 

 in certain dilution to attain specific results. The 

 army had to be supplied. Quantity production 

 took place and, after much experimentation, this 

 experience has now made it possible to supply 

 scientific dyes equal and in some cases, superior to 

 those formerly imported. Investigators should 

 mention that American dyes were used to obtain 

 their result for by this method proper encourage- 

 ment to this industry would be given. 



Chaeles L. Paksons, 

 Secretary 

 (To he continued) 



SCIENCE 



A Weekly Journal devoted to the Advancement of 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for 

 the Advancement of Science 



Published every Friday by 



THE SCIENCE PRESS 



LANCASTER. PA. GARRISON. N. Y. 



NEW YORK. N. Y. 



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