INDUSTRIAL A N D ENGINEERING CHEMISTRY
July, 1923
Erdmann allowed 10 min. for diazotization, but 1 min. appears sufficient. The time should not be too long, as the diazo compound is gradually hydrolyzed to methyl salicylate. RESULTSWITH Cy- AND /?-NAPHTHOLS-AliqUOtS Of 0.03116 g. from the solution of methyl anthranilate were taken, diazotized for 1 min., and poured into varying quantities of 0.2 per cent a- and /?-naphthol solutions in 30 per cent ethyl alcohol, adding sodium bicarbonate solution in 50 per cent excess. Weights in grams of precipitates with volumes of &naphthol were as follows: 15 cc., or calculated amount, 0.0580; 22.5 cc., 0.0588; 30 CC., 0.0584; 60 CC., 0.0560. The results with a-naphthol were: 15 cc., or calculated amount, 0.0610; 22.5 cc., 0.0628; 30 cc., 0.0628; 60 cc., 0.0582. Theory, 0.0631 g. While low results were obtained with /?-naphthol, the results with a-naphthol were close to theory. Precipitation with a-naphthol took place very quickly, the light, bulky precipitate rising t o the surface. With /?-.naphthol several hours are necessary for complete precipit.‘L t’ion. RESULTSWITH VARIOUSALKALIES-TO study in greater detail the action of different alkalies, the following series was run: Aliquots of 0.0324 g. of an alcoholic solution of methyl anthranilate were made up t o 200 cc. with water, diazotized for 1 min. with 5 cc. of N hydrochloric acid and 2 cc. of 5 per cent of sodium nitrite solution, and poured into beakers containing 20 cc. of 0.2 per cent solution of a-naphthol in 30 per cent ethyl alcohol, plus volumes of alkali noted. The weights of the precipitates thus obtained are given in Table I. TABLEI-WEIGHTS Xormal Alkali cc. 5 7.5 10 20
O F PRECIPITATES (THEORY, 0.0656 G.) NaOH NazCOa NaHC03 G. G. G. 0.0634 0.0652 0 0602 0.0622 0.0648 0.0540 0.0592 0 0624 0.0318 0.0130 0.0480 0.058s
The results with sodium bicarbonate as alkali are near theory. A moderate excess did not greatly lower the yield of precipitate. COLORIMETRIC METHOD-FOr colorimetric estimation of the ester, sodium hydroxide is the more suitable alkali, since, owing to its greater solvent action, higher concentrations of the dye remain in solution. While either of the naphthols gives a good color series, the colors produced when the alpha form is used are very much deeper. The following quantities of methyl anthranilate form a satisfactory series of standards: blank, 0.000006, 0.00001, 0.000025, 0.00005, 0.0001, 0.00015, and 0.00025 g. These quantities diazotized for 30 see. in 100 cc. with 1 cc. of N hydrochloric acid and 0.5 cc. of 5 per cent sodium nitrite are poured into Nessler jars containing 0.5 cc. of 2 per cent alcoholic a-naphthol solution and 3 cc. of N sodium nitrite. The maximum color develops within 15 min. and remains constant for several hours. A very slight color change occurs in the blank tube, but the difference between i t and the tube containing 0.000005 g. of the ester is pronounced. Amounts over 0.00025 g. produce colors rather too deep to be satisfactorily compared.
EXAMINATION OF COMMERCIAL PRODUCTS The methods developed were applied in the examination of grape juices, grape “pops” or bottled soft drinks artificially colored and flavored , and concentrated “grape” extracts used in compounding pops. The results are shown in Table 11. GRAPEJuIcEs-Having determined, by collecting a series of distillates from 500-cc. samples, that practically all the ester was carried over in the first 500-cc., this volume was
733
in each case steam-distilled, using a mercury seal and cooling the receiving flask in ice water. A 100-cc. aliquot of the distillate was treated and compared with a series of methyl anthranilate standards as described in the preceding paragraph. The samples examined were believed to be pure. Eight brands of Concord juice contained from 0.80 to 1.49 parts per million, and four brands of Catawba juice contained from 0.11 to 0.40 part per million of the ester. Power and Chestnut6 found that methyl anthranilate contents did not exceed 2 and 0.2 part per million with Concord and lightcolored juices, respectively. TABLE11-METHYL ANTHRANILATEC O N T E N T PRODUCTS
____ GRAPE JUICES--Concord Catawba Brand P D m Brand P 1-49 WS RP 1 42 BS VK 1 46 A W 1 18 M BS 112 G 0 96 AP 0.80
,---POPS--P D m Ser No P D 040 8964 17 0 13 8965 17 0 11 8556 7 0 08 S9l5 7
OF
COMMERCAL GRAPE
CONCENTRATED
EXTRACTS
m Ser No. G. Der 100 cc. 5 8632 b.342 0 B 0.270 3 B-l 0.320 1 B-2 0.513 B-3 0.477 8-4 0.510
GRAPE Pops-One hundred cubic centimeter volumes were steam-distilled to 500 cc., and 100-cc. or 50-cc. aliquots of the distillate were taken for colorimetric estimation. ARTIFICIAL GRAPE OSCENTRATED EXTRACTS-After preliminary study, the following method was applied: 25 cc. of sample were diluted to 100 cc. and steam-distilled to 500 cc., using a mercury seal and cooling the receiving flask in ice water. An aliquot of 200 cc. was diazotized for 1 min. with 5 cc. of N hydrochloric acid and 2 cc. of 5 per cent sodium nitrite solution. The diazotized solution was poured into 25 cc. of 0.2 per cent solution of a-naphthol in 30 per cent ethyl alcohol, and 6 cc. of N sodium bicarbonate. After 10 min. the precipitate was filtered on a 30-cc. weighed Gooch crucible, washed with 100 cc. of water, dried a t 100’ C. for 2 hrs., and weighed. Weight precipitate times 0.4935 equals weight of methyl anthranilate.
c
6
J . A m Chem. Soc., 43 (1921), 1741.
Meeting of Stamford Chemical Society The Stamford Chemical Society held its May meeting on the 28th at the Suburban Club, where about fifty men attended the dinner which preceded the evening program. Of these at least 20 per cent were business men and the gathering was especially honored by the presence of Hon. Schuyler Merritt, U. S. Congressman of the district. R. H. Stevens, president of the society, presided, and described the work of the society during the year. He introduced H. W. Banks, 3rd, who had been elected the next president. Mr. Banks spoke of his special interests in the coming work of the society and introduced Charles Wadsworth, 3rd, who acted as toastmaster. Mr. Wadsworth presented the Hon. Schuyler Merritt, who spoke on the lack of appreciation of chemistry during the last few years and referred to his own brief contact with the science in college days. He paid an extended tribute t o the war activity of chemists. He spoke at length of the need of science for world progress and emphasized his belief that science quickened and illuminated by religion will make possible the solution of present-day difficulties. F. H. Getman then described the work of the educational committee, which will soon award the prize of ten dollars for the best essay on chemistry in everyday life, common chemicals in the home, or chemistry in our local industries, submitted by high-school students in Stamford. Following out the suggestion that chemists cooperate in carrying the message of chemistry t o American women along the lines outlined in the Plea to American Women, the Committee on Education has been in communication with the Stamford Women’s Club, and arrangements have been made to include at least one address on chemistry during the next season. The final speaker of the evening was H. E. Howe, who spoke on “Factors in Scientific Progress,” stressing the importance of organization as one of the outstanding requirements in furthering scientific work.
