COMMEECIAL PRODUCTION OF THYMOL FROM HOESEMINT. 9 



A sample of 28 pounds of liorsemint oil, showing on assay 72 

 per cent of total phenols, was worked up by this process and 18 

 pounds of pure thymol was manufactured from it, which is equal 

 to a commercial yield of 64.3 per cent of thymol from the oil. When 

 made by this process a perfectly white crystalline product was 

 secured; 15 pounds of thymol made by this process in 1915 was 

 sold to the trade at a high price. Should a slightly yellow product 

 be secured a second distillation would be required. It has been 

 found, however, that with ordinary care a high-grade product will 

 result from the first distillation. By this process three residues are 

 secured in small quantities, the lower boiling fraction consisting 

 largely of cymene, the mother liquor from the last crystalHzation of 

 phenols, and the tarlike residue remaining in the retort after the last 

 fraction has been removed. Work is at present under way looking 

 to the utilization of these residues. 



In order to provide an inexpensive and practical apparatus for 

 the extraction of thymol from the oil on a moderate scale, the follow- 

 ing apparatus has been devised: 



(1) A flask 12 inches in diameter and 16 inches high, made of about 30-ounce copper. 

 The top is brought to a short neck 3 inches in diameter and reenforced by a brass 

 band half an inch wide and one-quarter inch thick, turned edgewise to form a ring 

 and brazed to the neck, forming a flange. The seam in the flask must be brazed, 

 since the temperature of the boiling oil is above the melting point of solder. 



(2) A column 22 inches long of 3-inch thin-walled brass or copper tubing. The 

 lower end is fitted with a brass ring of the same size and in the same manner as the 

 neck of the flask and with it forming a flange joint. In the lower end of the column 

 is brazed a brass or copper disk, set at an angle of about 30°. The top of the tube is 

 covered with a cap, brazed on, and in the center is set a piece of three-fourths inch 

 brass tubing, about 1 inch long, forming a neck, into which a cork can be fitted. 

 About 4 inches below the top a dde tube of 1-inch brass tubing is brazed in a slight 

 angle downward. This tube should be about 20 inches long and at the free end 

 Bhould have an elbow which just fits into the end of the condenser. 



The condenser is of copper, 4^ inches in diameter and about 20 

 inches long, and consists of an outer cylinder with a head at each 

 end. Running through from one head to the other are seven quar- 

 ter-inch tubes of copper or block tin. A side tube at the bottom 

 and one at the top serve for the inlet and outlet of the cooling water, 

 which moves from the bottom upward about the flues. To each 

 end is soldered a brass collar 2 by 2 inches, which serves as a chamber 

 about the ends of the flues. This sUps over the enlarged end of the 

 delivery tube at the top to form a fairly tight joint, while over the 

 bottom collar is placed a funnel-shaped nozzle to collect and dehver 

 as one stream the liquids which run down the flues. The entire 

 condenser can be made with soldered joints, since the water jacket 

 will prevent melting. A complete condenser can be bought from 

 dealers in chemical and pharmaceutical apparatus or can be made 

 at small expense by any good coppersmith. 



