70
I N D U S T R I A L A N D ENGINEERING CHEMISTRY
of this complex will give solutions with a constant ratio of arsenic acid to lime, which has misled previous investigators to consider the complex a definite compound. There seems to be no evidence that tricalcium arsenate can be formed from aqueous solutions, nor persist in contact with them. Analytical methods purporting to separate it from other calcium compounds should be riewed with caution.
Vol. 21, No. 1
Tricalcium arsenate may be formed, as in the Cullen process, where calcium oxide and arsenic trioxide are heated in a current of air. As far as the writers know, the products so obtained are not crystalline, and one may well hesitate to express a positive opinion. That any one of them will, in contact with water, form two solutions, one solid, the other liquid, is reasonably certain.
Deterioration of Soap-Nicotine Preparations-11’ C. C. McDonnell and J. J. T. Graham FOOD,DRUG,AND INSECTICIDE ADMINISTRATION, U. S. DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C.
N OUR work in connec-
Commercial soap-nicotine preparations decrease kettle and heated somewhat in nicotine content on storage. This loss is shown to tion with the e n f o r c e below looo C. until the soap merit of the Insecticide be due to volatilization of nicotine and, in the case of attained a pasty consistency, Act it has been found that soaps made from drying oils such as fish oil, to oxidation when it was transferred to a most of the commercial soap which results in a condensation product between the shallow, flat, enameled pan preparations containing niconicotine and the fatty acids. The work here reported to cool. Small quantities of tine, especially those in cake shows that this decomposition can be prevented by water and nicotine were lost form, contain less n i c o t i n e packing the soaps S O that they are completely protected d u r i n g saponification, but t h a n t h e manufacturer from the air and that such products can be produced c o m p l e t e a n a l y s e s of the and marketed S O as to retain their nicotine content for finished soaps were made, claimed to be present. Sevat least two years. Fish-oil soaps were used in era1 years ago an investigamost of the work. They were tion to determine the cause of this shortage was begun. I n a previous paper McDonnell prepared in three types-neutral, alkaline, and superfatted and Nealon2 reported that hard soaps made from sodium hy- soda soaps (both in cake and paste form), and neutral and droxide, menhaden fish oil and nicotine solution lose nicotine alkaline potash (soft) soaps. The cottonseed oil, red oil, rapidly on storage regardless of the type of package, and that and stearic acid soaps were prepared only in the neutral form. potash soaps (soft soap) and soft soda soaps containing nico- The formulas are given in Table I. tine retain practically their original nicotine strength for a Soft soda soaps were prepared from portions of the hard period of four years. I n other words, whether or not nicotine soaps A, B, C, I, and K by adding a sufficient quantity of is lost depends upon the physical condition of the product. water to convert them to the consistency of a thin jelly and It was further reported that any loss of nicotine was due, not then enough nicotine solution to make the total nicotine to volatilization, but t o chemical changes, whereby it was content approximately 3 to 4 per cent. These were desigconverted into an insoluble, non-volatile, polymeric form nated D, E, F, J, and L. All the samples were packed in or a condensation product, probably the latter, as the de- glass jars fitted with rubber rings and tightly closed. The crease in nicotine was accompanied by a decrease in the hard soaps were cut into cakes about 4 X 4 X 10 cm. and fatty acids of the soap, indicating a reaction between the two. wrapped in heavy waxed paper before being placed in jars. The present paper reports the results of additional work A sufficient number of cakes was prepared so that a fresh on this subject, including that with soaps made from different cake could be taken for each analysis, and all samples were analyzed a t the time of packing and after storage for 1, 3, types of oils, both drying and non-drying. 5, 8, 12, and 24 months.
I
Preparation of Samples
Soda and potash soaps were prepared with the follotving oils and fatty acids: menhaden fish oil, cottonseed oil, linseed oil, red oil, and stearic acid. Nicotine was added in the form of a water solution of the ‘‘free” alkaloid. Note-Soaps containing nicotine sulfate solution, which is the most common form of commercial nicotine preparations, would no doubt act in the same way. Since alkali or soap sets nicotine free from nicotine sulfate, its use would have liberated fatty acids and added an additional factor in making i t necessary t o provide for more alkali in order t o produce a neutral soap.
The saponification values of the oils and fatty acids were determined, and the exact amount of alkali solution (prepared practically free from carbonate) required to form a neutral alkaline or superfatted soap as desired was added. Saponification was accomplished in a jacketed steam kettle equipped with an agitator, the ingredients being added to the hot 1 Presented as a part of the Symposium on Insecticides and Fungicides before the Division of Agricultural and Food Chemistry a t the 75th Meeting of the American Chemical Society, St. Louis, Mo., April 16 to 19,
Methods of Analysis
In order to secure a representative sample, a section through the center of the cake of the hard soaps was taken in each case, and the soft soaps ere thoroughly mixed and a pertion was removed for analysis. W a ~ ~ ~ - W a t ewas r determined by distilling 15 to 20 grams Of the With 50 Of dry (about lo grams Of lump rosin being added to prevent foaming) and the distillate was collected in a distilling tube and measured, according to the method described b i Dean and Stark.3 ’ FATTY Acms-For the determination of fatty anhydrides, nicotine, and insoluble material, a weighed sample of approximately 20 grams was dissolved in hot water and transferred to a separatory funnel and an excess of hydrochloric acid was added. After the solution was cool the fatty acids were extracted with ether, the ether was evaporated in a weighed beaker and the residual fatty acids were weighed. The residue in the separatory funnel was dissolved in alcohol and transferred to a weighed beaker. The alcohol was
1928. 2
IND. ENG.CHEM.,16, 819 (1924).
a
J. IND. ENG.CHEM, 12, 486 (1920).
T a b l e I-Formulas NATUREOF SOAP
71
INDUSTRIAL A N D ENGINEERING CHEMISTRY
January, 1929
LINSEED OIL
Grams
STEARIC ACID
Giams
Used in M a k i n g Soap-Nicotine P r e p a r a t i o n s a
OLEIC RED OIL Grams
NICOTINE SOLUTION COTTONSEEDMENHADEN POTASSIUM SODIUM HYDROXIDEHYDROXIDE (40%) OIL FISHOIL Grams Grams Grams Grams cc.
WATER
cc.
Soda-fish oil: 447 400 1600 .. A-Neutral, hard 500 400 1600 .. B-Alkaline, hard 350 1600 425 .. C-Superfatted, hard 47 1 700 1600 I-Neutral, hard Potash-fish oil: 2000 .. ... 375 G-Neutral soft .. .. .. 3400 660 2000 .. ... 350 H-Alkalin;, soft .. .. .. 3400 700 Soda-cottonseed oil: 2200 .. 475 350 IC-Keutral, hard .. .. 3400 ... Potash-cottonseed oil: 2000b M-Neutral. soft .. 375s .. .. 3400 .. 666 Soda-oleic red’oil: .. .. 3400 .. .. .. 16000 N-Neutral, hard 485 350 .. .. 0-Neutral, soft .. 3400 .. .. 485 350 1600 Potash-oleic red oil: .. P-Neutral, soft 350 2000 .. 3400 .. .. 679 Soda-stearic acid: Q-Neutral, hard .. 3400 .. .. .. ... 1600 511 350 Potash-stearic acid: .. ... 225 R-Neutral, soft 3000 1700 .. .. 358 Soda-linseed oil: 860 .. .. ., .. ... 400 125 100 X-Alkaline, hard 5 The saponification number of the oil used in the preparation of samples A, B , C. and H was 184.0; t h a t of the oil used in G and I, 194.2, and those of the cottonseed oil, red oil, and stearic acid were 195.89, 199.8, and 210.5, respectively. b It was necessary to add additional mater to this sample t o bring i t t o the desired consistency; additional nicotine solution was also added so t h a t the finished product contained about 2.5 per cent of nicotine. c In order t o produce a hard soap it was necessary to evaporate a part of the water from this sample.
..
..
..
...
..
evaporated and the residue was dried a t 105’ C., weighed and reported as “ether-insoluble residue.’’ P\TIcoTrNE-The extracted aqueous solution was made alkaline and steam-distilled and the nicotine was determined by precipitation with silicotungstic acid according to the method of the A. 0. A. C.4 NITROGEN-Nitrogen was determined by the KjeldahlGunning-Arnold method, the digestion being continued long enough to convert all the nitrogen of the nicotine into ammonia. From the percentage of nitrogen obtained the nicotine equivalent was calculated. ALKaLI-Alkali was determined by ashing approximately 5 grams of the soap in a platinum dish, dissolving the ash in water and titrating with a standard acid solution. The results of analyses are given in Table 11. Results An examination of the results shows that a t the expiration of 12 months: (1) All the hard soaps had lost nicotine, although in only two cases was the loss in excess of 0.25 per cent. Note-Sample (XI, the linseed oil soap, was not prepared until after the investigation had been under way for some time and the results showed that the drying or non-drying quality of the oil used had an influence on the loss of nicotine. It was stored for only 8 months, with an intermediate analysis at the expiration of 5 months.
( 2 ) The loss of nicotine from the soft soaps, with one exception, was practically negligible. (3) Excess of alkali or of fat in the soap had no apparent influence on the rate of loss of nicotine. (4) The average loss of nicotine from hard soaps prepared from drying or semi-drying oils was greater than that from soaps prepared from the non-drying oils.
The samples were analyzed after an additional 12-month period of storage under the same conditions, and the results indicate that the same general conclusions apply as for the first 12-month period. The physical appearance of the hard soaps after storage was also of interest. Those prepared from red oil and stearic acid showed no change, but, n-ith two or three exceptions, the samples prepared from fish oil and cottonseed oil had developed a discolored layer, ranging from a light brown to black, which extended into the cake for from 2 to 6 mm. This layer contained the black resinous material noted by McDonnell and Nealon2in the hard soda fish-oil soaps after storage. In one case in which no discoloration occurred it Assocn. Officidl Agr Chem., Methods, p 66 (1926).
was noted on opening the jar that there was an inrush of air, indicating that the jar had been hermetically sealed and that the oxygen had been used up. Also in two other cases the cakes showed no discoloration and the nicotine content was the same as when packed. These facts pointed to some connection between the nicotine loss and oxidation. Note-It was assumed t h a t t h e small amount of oxygen in the jars that were hermetically sealed was not sufficient t o cause any appreciable change and t h a t where loss of nicotine and marked discoloration occurred the jars were not air-tight.
Effect of Contact with Air on Deterioration In order to verify the theory that the deterioration of the soaps was caused by contact with the air, the soaps from the jars in which there had been the least deterioration after 12 months’ storage were trimmed of all the discolored layer and packed in the following ways: (1)unwrapped and placed in glass jars, care being taken to see that they were tightly sealed; (2) wrapped in tin foil, then heavily coated with paraffin by dipping to give complete protection from the air; (3) wrapped in heavy waxed paper, but not completely airtight, and stored in a dark closet; (4) the trimmings from these repacked soaps stored in a glass jar but not sealed. I n view of the observation that the soaps prepared from drying oils deteriorated more rapidly than those made from non-drying oils, it was decided to study also the effect of storage under the conditions just described on a soap prepared from linseed oil and containing nicotine. (Sample X, Tables I1 and 111) I n order to determine the influence of contact with the air on the potash (soft) soaps containing nicotine, portions of samples G and H were stored in glass jars and covered only with filter paper to exclude the dust. These samples mere stirred occasionally in order to insure more thorough contact with the air, and water mas added from time to time to replace that lost by evaporation. They were exposed in this manner for 17 months. All these samples were analyzed a t the end of 12 months except the linseed oil soap, which was stored for only 5 months. The results of this experiment are given in Table 111. As the manner of storage caused a marked drying of the samples in some cases, all results in this table are reported on a water-free basis. In order to illustrate more clearly the effect of air on the two classes of soaps, graphs embodying the data under the subheadings ( 2 ) , (3a), and (3b) in Table I11 were prepared.
72
INDUSTRIAL AND ENGINEERTNG CHEMISTRY T a b l e 11-An
NICOTINE (Calcd. TIMEOB NICOTINE from STORAGE (Detd.) nitrogen) WATER Months Per cent Per cent Per cent When made
1
3
5 8 12 24
3.18 3.14 3.01 3.02
2.93 2.95 2.75
ETHERFATTY ANHYDRIDES
Per cent
SAMPLE A
3.3
... ... ... .... .. 3.1
19.2
..
lB:3 1e:9 19.3
IN-
SOLUBLE
RESI-
ALKALI D U E P e r cent Per cent (NazO)
63.2 63.4 62.1 63.0 62.9 62.6 62.2
9.6
58.9 59.4 58.9 59.3 59.3 58.8 57.4
9.7
... ... ... ... ...
...
None Trace Trace Trace Trace Trace
1.8
SAMPLE B
When made
1 3 5
8 12 24
2.53 2.53 2.50 2.46 2.45 2.37 1.99
2.7
..
24.8
...
23:9
... 2.5
2b:0 24.0
... ...
... ... ... ...
None Trace Trace Trace Trace Trace
2.4
SAMPLE C
When made
1 3 5 8
12 24
2.66 2.63 2.50 2.59 2.61 2.52 2.06
2.7
... ... ... ...
2.1
22.0 2214 22:2 22.1
62.4 62.4 61.6 62.8 62.7 62.7 60.8
8.7
24.4 24.0
3.7
... ...
... ... ...
...
None Trace Trace Trace Trace Trace
2.6
SAMPLE D
When made 1
3 5
8
12 24
3.83 3.84 3.83 3.82 3.79 3.74 3.65
3.8
.. .. ..
66.2
..
...
60:2
...
60:2 65.7
...
3.8
2k:4 24.4 24.5 24.2
... ... ... ...
...
...
None Trace Trace Trace Trace Trace
0.2
SAMPLE E
When made
1 3
5
8
12 24
3.47 3.49 3.47 3.58 3.52 3.50 3.54
3.5
...
62.4
... ...
62:5
3.8
..
62:O 61.9
27.2 27.2 27.2 27.6 27.6 27.6 28.4
4.4
25.4 25.5 25.4 26.6 25.4 25.4 25.4
3.5
...
... ...
...
...
...
None Trace Trace Trace Trace Trace Trace
SAMPLE F
When made
1 3 5
8 12 24
3.08 3.09 3.08 3.05 3.10 3.08 3.08
3.2
...
65.9
... ...
65:7
...
...
3.2
..
6811 66.1 SAMPLE G
When made
1 3 6 8 12 24
2.76 2.75 2.65 2.73 2.73 2.73 2.65
2.9
27.8
... ... ...
20:7
...
...
3.0
..
2i:o 24.7
56.2 56.1 56.3 56.2 56.3 56.3 56.9
... ... ... ... ...
...
(52.2)
None Trace Trace Trace Trace Trace Trace
... ... ... ... ... ...
Pjone Trace Trace Trace Trace Trace Trace
11.0
Kone Trace Trace Trace Trace Trace Trace
SAMPLE H
When made 1 8 5 8
12 24
2.39 2.41 2.44 2.42 2.43 2.43 2.40
2.4
... ... ... ... ...
2.5
19.2
..
16:5 19:s 20.0
59.5 59.7 59.6 59.6 59.9 59.8 60.0
.. .. ..
... ...
...
...
SAMPLE I
When made
1 3 5
8
12 24 When made
1 3 5
5.79 5.48 5.35 5.51 5.35 4.96 4.64 5.84 5.84 5.82 5.81
5.7
.... .. ... ...
5.7 6.1
... ... ...
19.0 19:o 17:s 18.4 SAMPLE J
63.9
..
6414
Vol. 21, No. 1
alyses of Soap-Nicotine P r e p a r a t i o n s S t o r e d in Glass Jars
61.7 60.9 60.8 61.8 61.8 60.6 59.2 24.4 24.5 24.3 23.7
(h’azO)
7.8
... ... ... ... ...
...
2.6
...
.. .. ..
TIMEOF
STORAGE tDetd.) Months Per cent
8
12 24
When made 1
3 5 8 12 24 When made 1
3 5 8 12 24
0.3 0.5
... ... 3.3
5.83 5.82 5.84 2.52 2.40 2.27 2.02 1.88 1.59 1.33 2.97 2.87 2.85 2.85 2.78 2.73 2.72
NICOTINE (Calcd. from nitrogen) WATER Per cent Per cent
...
...
6.2
Figure 1 represents the average of the data for the drying oil soaps, and Figure 2 that for the non-drying oil soaps. The nicotine originally present is plotted as 100, and the average percentage remaining a t the end of a year is calculated to percentage of that originally present and plotted, thus indicating the rate of loss. At the end of the 12-month storage period there was no discoloration or evidence of physical change in any of the samples packed in tin foil and paraffined, nor in those unwrapped and packed in sealed glass jars, with the exception of sample (I), which was high in nicotine. Neither was there any change in the physical appearance of the soaps made
ANHY-
DRIDES
Per cent
Per cent (NazO)
24.4 24.4 24.4
... ...
Trace Trace Trace
62.0 61.4
7.0
None Trace Trace Trace Trace Trace
SAMPLE J
6414 64.7
INSOLUBLE RESIALKALI DUE
...
Per cent
SAMPLE K
2.6
...
... ... ...
2.5
22.5 2i:8 l9:6 21.4 SAMPLE
3.0
... ... ... ...
...
3.1
When made
1 3 5 8 12 24
2.32 2.30 2.28 2.22 2.20 2.18 1.99
2.5
2.94
3.1
2.5
... .... ..
... ...
...
... ... ... ...
6i:6 61.6 62.5 60.8
...
1.75
L
74.3
..
19.1 18.6
2.2
74:1
l8:7 18.4 18.6 18.9
... ..,
73:s 73.6 71.7
..
70:5 70:6 71.3 SAMPLE
Whp.n made 1
3 5
8 12 24
2:03 2.93 2.93 2.83 2.64
... ...
... ... ...
... ... ...
...
None Trace Trace Trace Trace Trace Trace
3.1
20.9 20.7 20.7 20.2 20.6 20.6 20.6
(Kz0) 3.6
... ...
... ... ... ...
None Trace Trace Trace Trace Trace Trace
N
17.9
..
1i:2 li:6 17.0
70.4
(NazO)
10.9
None
...
T&e Trace Trace Trace Trace
... ...
7212 71.6 71.4 71.8 71.7
...
58.2
9.0
None
... ... ...
T&e Trace Trace Trace Trace
... ...
SAMPLE 0
When made
1 3 5
8
12 24
2.49 2:51 2.52 2.49 2.47 2.44
2.7
... ...
... ...
...
2.7
31.6
..
3i:3 3i:8 30.7
... ... ...
59:l 59.3 58.6 58.8 59.7
SAMPLE P
When made 1
3 5 8
12 24
2.45 2.48 2.46 2.50 2.47 2.43 2.14
2.6
...
35.8
..
.. .. ..
34:5
2.6
3i:9 35.1
... ...
52.3 52.7 53.8 53.4 53.0 53.2 52.7
(Kz0) 9.0
... ... ...
... ...
...
None Trace Trace Trace Trace Trace Trace
SAMPLE Q
When made
1 3 5
8
12 24
2.33 2.28 2.37 2.41 2.47 2.34 2.27
2.4
... ...
... ... . I .
2.3
31.5
..
32:5 32:2 32.6
59.5 60:Q 60.9 58.5 57.7 59.6
(NazO)
9.6
None
... ... ...
Trace Trace Trace Trace Trace
...
... ...
...
SAMPLE R
1 3 5 8 12 24
1.95 1.94 1.97 1.97 1.94 1.95 2.05
2.1
2.1
3.84
*.
3.9
...
3:i6 3.13
3.9 4.0
... ... ... ...
...
3.7 Trace Trace Trace Trace
ETHERFATTY
SAMPLE M:
When made Trace
NICOTINE
55.4
31.0
3 5 8
...
6.5
... ... ...
None Trace Trace Trace Trace Trace Trace
17.8
..
63.7
...
h‘one
18:4 18.6
62:s 61.8
5i:7 5i:3 54.9 SAMPLE X
When made 1
E z 0 )
30:4 37.0 37.1 36.7 36.2
..
..
...
... ...
... ... ... .
.
I
...
...
Trace 0.9
from oleic red oil or stearic acid, other than loss of moisture, regardless of how they were packed. The fish-oil, cottonseed-oil and linseed-oil soaps stored in paper wrappings (not air-tight), however, showed marked discoloration which extended to a depth of from 2 to G mm. An examination of the chemical results sheds much light on the deterioration of nicotine soaps and indicates how the loss of nicotine can be prevented. In the samples packed so as to exclude the air entirely, there was practically no loss of niaotine, except a slight deterioration in the samples packed unwrapped in sealed glass jars, in which cases the soaps were exposed to the small amount of air contained in the jars.
IiVDCSTRIAL AiVD EXGIITEERI~VGCHEMISTRY
January, 1929
The soaps wrapped in waxed paper (not completely protected from the air) showed considerable loss of nicotine. The fish-oil (a drying oil) soaps showed much surface discoloration, a loss in fatty acids as well as in nicotine and a large insoluble residue. The nicotine equivalent of the total nitrogen, however, was practically the same as the actual nicotine originally present. The soaps prepared from cottonseed oil (a semi-drying oil) reacted very similarly, but did not show so great a loss in fatty acids nor so large an insoluble residue. Here again the nicotine calculated from the nitrogen content of the sample was as high as the nicotine originally present. I n the soap prepared from linseed oil (a drying oil) there was also a loss and fixation of the nicotine, but apparently little change in the fatty acids and very little insoluble residue was formed. The fixation product in this case was mostly soluble in the ether and was weighed along with the fatty acids. Table 111-Analyses
of Soaps after Storage of One Year Packed in Different Ways (Results calculated t o dry basis)
NICOTINE
Calcd. from FATTY INSOLUBLE nitrogen ANHYDRIDES MATERIAL Per cent P e r cent P e r cent Trace 4.08 78.1 0.3 78.8 4.05 Trace 79.1 4.15 29.5 48.2 4.95 0.5 78.8 4.07 25.5 51.7 3.83 Trace 3.58 78.4 0.7 3.46 77.9 0.3 3.49 79.2 13.6 3.64 62.7 0.3 3.46 78.9 12.8 3.42 59.5 Trace 3.46 80.0 0.5 3.42 80.3 0.4 3.59 79.5 19.3 3.79 62.4 0.4 3.34 79.9 17.9 59.2 3.31 Trace 7.00 76.1 13.5 6.70 58.4 0.6 77.4 6:93 0.8 76.0 6.50 16.2 55.3 6.02 0.7 77.3 7.51 24.8 50.7 Trace 3.41 80.0 Trace 3.33 78.2 Trace 3.31 79.7 3.52 72.6 3.6 2.79 Trace 78.7 3.40 6.9 74.1 3.58 3.84 85.8 Trace N(O) 3.85 Trace 3.25 86.3 NU) Trace 86.2 3.86 3.53 Trace 1.72 87.6 2.33 Trace 3.15 3.09 84.6 N(3b) Trace 3.14 3.15 86.2 N(4) 3.40 3.46 Trace 86.9 3.64 Trace 3.23 85.3 3.19 3.74 Trace 85.5 Q (2) 1.24 Q(3d 0.90 Trace 87.8 1.51 Trace 1.35 87.9 Q (3b) 3.04 Trace 85.6 3.28 Q (4) x (0) 4.67 4.91 77.5 None 4.90 X(1) 3.84 75.8 1.1 X(2)0 4.51 4.93 75.6 0.3 X(3)C 2.76 4.65 75.9 0.9 X(4)C 2.75 4.60 75.0 0.9 G 3.82 4.05 77.8 None Gb 2.32 3.48 71.3 3.2 H 2.69 2.68 None 67.1 Hb 2.19 2.78 72.5 2.4 (0) Analysis a t time of preparation. (1) Stored unwrapped in sealed glass jars. (2) Stored wrapped in tin foil and dipped in paraffin. (3) Stored wrapped in waxed paper (not air-tight) in dark closet. (4) Trimmings from soap, stored in glass jars without rubbers (not air-tight). - . ( a ) Outside layer of soap. ( b ) Inside portion of cake. ( c ) Stored for 8 months. ( d ) Stored for 17 months.
SAMPLE
Detd. P e r cent
881
The soaps prepared from (non-drying oils) packed in There was a loss of nicotine, the drying oil soaps, but no
oleic red oil and stearic acid this way behaved differently. although not so great as with reaction between the nicotine
73
and the fatty acids occurred. The loss appeared to be due simply to a volatilization of the nicotine. The soft soaps G and H exposed to the air lost nicotine much less rapidly than the hard soaps to which the air had access. It is of interest to note that it was the fatty acids of the drying or semi-drying oils with which the nicotine reacted to form the insoluble (soluble in the case of the linseed-oil soap) resinous material and that there was no such reaction with the non-drying oils. Moreover, where loss of nicotine occurred, the nicotine, calculated from the nitrogen de”’ 32” termination, in the sur‘2 3b face layers of the soaps a. made from the drying , 6 36 oils is g r e a t e r a f t e r -. storage than that con- $ s o tained in the center of a the cake and g r e a t e r 3 than that o r i g i n a l l y & p r e s e n t , while in the case of soaps made from Period o f s t o g e -Months. the non-drying oils it is less in all parts Of the Figure I-Soaps from Drying Oils cake but the greater decrease has occurred a t the surface. This is explained on the basis that, while there is an actual loss of nicotine in both cases, it volatilizes from non-drying oil soaps, but in the drying oil soaps it is fixed through reaction with the fatty acids and oxygen of the air. No extended investigation was made to determine the exact composition of the resinous material. However, the work done showed that it was of indefinite composition. It contained nitrogen in quantities ranging in different samples from 0.8 to 3 per cent, equivalent to from 4.5 to 17 per cent of nicotine, but only traces of nicotine could be obtained by adding sodium hydroxide to the residue and distilling with steam. Summary
Soap-nicotine prepa- c o, rations ordinarily 50 found on the market d e c r e a s e i n nicotine content on storage. Y Hard soda soaps lose nicotine more rapidly on exposure to the air t h a n potash soaps. %;od o f S t o r g e -Mo&..r. H o w e v e r , s o f t soda Figure 2-Soaps from Non-Drying Oils soaps and potash (soft) soaps lose it a t about the same rate. Excess of alkali or fat in the soaps has no appreciable influence on the rate of loss of nicotine. The loss of nicotine from soap-nicotine preparations made withdrying oils (fish oils, cottonseed oi1,linseed oil) and packed so that air is not excluded is due mainly t o oxidation, the nicotine with part of the fatty acids of the soap being converted into an insoluble condensation product of indefinite composition. The loss of nicotine from soap-nicotine preparations made with non-drying oils (oleic red oil, stearic acid) and stored without air being excluded is due to volatilization of nicotine, no insoluble condensation product being formed. Both hard and soft soaps, whether made from drying or non-drying oils, when packed so that they were completely protected from the air, suffered no loss in nicotine content during two years of storage.
