T H E J O U R N A L OF I N D U S T R I A L A N D E Y G I i V E E R I N G C H E M I S T R Y drying and weighing. Excess alcoholic alkali can be used without affecting t h e coumarin results if it is n o t desired t o determine t h e vanillin volumetrically. It has been found t h a t benzene, chloroform and ether are t h e best solvents for extracting vanillin and coumarin from either aqueous or alcoholic solutions. F o r t y cc. of chloroform, I O O cc. of benzene and 6 0 cc. of ether in four or five extractions will extract quantitatively large amounts of vanillin from water and alcohol solutions u p t o 2 j per cent strength. Since a half aliquot is usually taken for analysis this corresponds t o j o per cent alcohol in t h e extract which is probably more t h a n t h e average commercial extract contains. Benzene, chloroform a n d ether all extract acids and coloring matter from vanillin extracts treated with lead acetate, ether extracting b y far t h e most. Hence ether cannot be used if t h e vanillin is t o be determined by titration, because t h e acetic acid it extracts a t t h e same time cannot be removed b y washing. Benzene or chloroform can be used for such purposes. There is, therefore, a possibility of combining a volumetric vanillin with a gravimetric coumarin determination in such cases where t h e qualitative test shows t h e presence of t h e latter. The details of a volumetric vanillin determination will be published later. However, if results for coumarin only are desired, it is recommended t h a t ether be used as t h e extracting solvent as it has decided advantages in such cases. It evaporates more quickly and tho extractions and washings are speedier because ether and water can be separated faster t h a n water and chloroform or water a n d benzene. While ether extracts considerably more coloring matter a n d acid t h a n benzene or chloroform from vanilla solutions, these impurities are neutralized b y t h e alkali a n d removed with t h e vanillin in t h e subsequent washing with water. A water-white solution of coumarin in ether remains. The ether can be evaporated a n d t h e coumarin dried and weighed. S o dealcoholization is necessary a n d t h e results can be obtained speedily. I t is n o t recommended in quantitative work t o extract t h e coumarin from alkaline vanilla solutions as in t h e qualitative method, because emulsions are liable t o form, and coloring matter must be removed anyhow. I n many cases where speed is desirable it would be advantageous t o determine coumarin in one portion a n d t h e vanillin b y colorimetric or other m'ethods in another. To show t h e results t h a t can be obtained by t h e above method t h e following d a t a are submitted: To 5 0 cc. of vanilla extract various quantities of coumarin were added, the vanilla solutions then treated with lead acetate without dealcoholization, made up to 100 cc., filtered, and the excess lead precipitated with dry potassium oxalate. The removal of the lead facilitates extraction because i t reduces emulsion formation. Fifty cc. of the solutions thus prepared were extracted with ether, benzene or chloroform, as indicated in the table, a few drops oE phenolphthalein solution and excess alcoholic alkali added and the vanillin salt removed by washing with several I O cc. portions of water. The disappearance of the red phenolphthalein color in the wash water is an indication of sufiicient washing. The washed solutions containing the cou-
53 7
marin were evaporated and the coumarin dried and weighed. The results are given in Table I. Coumarin added Mg. 25.0 24.5 24.5 25.0 25.0 25.0 5.0 10.0 15.0 25.0 50.0
Extracting solvent Benzene Benzene Chloroform Chloroform Ether Ether Ether Ether Ether Ether Ether
TABLEI Quantity of extracting Number Coumarin of recovered solvent Cc. extractions Me. 100 5 2415 24.0 100 5 40 4 24.0 4.0 . 4 25.2 80 4 25.2 80 4 24.8 80 4 4.8 80 4 10.2 80 4 15.0 80 4 24.5 80 4 49.3
Coumarin recovered Per cent 98.0 97.9 97.9
98.0 98.6
T h e results shown in t h e table indicate t h a t an accurate quantitative determination of coumarin can b e made b y t h e method outlined above. Quicker methods for lead number and vanillin, t o correspond with t h e coumarin method, are in preparation. SUMXARY
A simple and quick modification of t h e original method for t h e detection of coumarin in factitious vanilla extracts has been developed. While quantitative results based on t h e qualitative method are too low, another method has been given which is shown t o be both quick and accurate for t h e determination of coumarin. u.s. DEPARTMENT OF AGRICULTURE FOODAND DRUGINSPECTION LABORATORY DENVER,COLORADO
THE DETERMINATION OF ESSENTIAL OILS IN NONALCOHOLIC FLAVORING EXTRACTS By
FRANK M. BOYLES
Received March 28, 1918
There has been appearing for some years on t h e American market, in increasing numbers, a variety of so-called non-alcoholic flavoring extracts which consist essentially of an emulsion of t h e respective essential oils in mucilage of acacia, tragacanth, karaya, or other gums. Glycerin is quite often present. I n making a survey of these products, t h e writer tried first t h e method suggested b y Redfern' which was found t o be quite unsatisfactory; first, because t h e procedure of precipitating t h e gum from 2 5 cc. of t h e sample with 2 j cc. of 95 per cent alcohol a n d filtering through a Gooch into a I O O cc. flask a n d making up t o t h e mark was too tedious and timeconsuming; and second, because t h e writer did not in this case, and never has been able t o obtain concordant results b y t h e method of Howard2 t o which Redfern refers. Indeed this method is' even less adaptable t o t h e non-alcoholic extracts t h a n t o t h e ordinary alcoholic extracts, for t h e reason t h a t t h e former contain, in a number of cases, as much as four times more oil t h a n t h e strictly standard alcoholic extracts a n d there is always danger, if not certainty, of losing oil through volatilization when from I O t o 2 0 per cent is present. Taking advantage of t h e fact t h a t many gums are precipitated b y lead subacetate, t h e following procedure was tried: 5 cc. of t h e emulsion were diluted with 2 0 cc. water and transferred t o a Babcock milk 1 2
THISJOURNAL, 8 (1916), 421. J . A m . Chcm. SOC.,SO (1908), 608.
538
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
bottle and t h e gum precipitated b y lead subacetate a n d centrifuged. T h e precipitated gum came t o t h e top and t h e volume of oil could not be read. This was t h e n modified b y adding chloroform t o absorb t h e oil after precipitation of t h e gum. On centrifuging this mixture t h e gum precipitate settled t o t h e bottom of t h e bottle with t h e chloroform, and upon decanting t h e supernatant liquid, adding ether, and heating t o expel t h e chloroform as recommended b y Howard a n d then diluting with water and centrifuging, t h e gum precipitate came t o t h e top with t h e oil and again interfered with t h e reading of t h e volume of t h e oil. Finally t h e following method which consists simply of making a n alcoholic extract from t h e emulsion and proceeding according t o t h e official method’ was found t o give satisfactory and concordant results for the lemon and orange extracts 41E T H 0 D
Measure I O cc. of the emulsion into a graduated cylinder, transfer as much as possible to a j o cc. flask, rinse the cylinder with I O cc. portions of 95 per cent alcohol, and with the aid of a glass rod transfer all of the emulsion and precipitated gum to the flask, fill to the mark, shake thoroughly, let stand about 30 min. Filter through a folded filter and determine the oil in a 2 0 cc. portion of the filtrate by the official meth0d.l The per cent of oil found in the filtrate is multiplied by 5 to give the per cent of oil in the original emulsion. The gum is completely precipitated and i t is more expeditious t o throw down t h e gum in t h e volumetric flask and t o make u p t o volume a n d use a n aliquot of t h e filtrate t h a n t o precipitate t h e gum and a t tempt t o wash the oil from it into t h e flask. I t is possible t o pipette t h e aliquot directly from t h e flask, b u t as t h e precipitated gum gathers a t t h e shoulder of t h e flask and frequently stops t h e outlet of t h e pipette this procedure offers little advantage over filtering, as it is not necessary t o avoid transferring t h e gum t o t h e filter. I n t h e case of extracts containing less t h a n j per cent oil it is necessary t o use more sample t h a n specified in t h e directions given. Non-alcoholic extracts of lemon and orange containing I O per cent of t h e respective oils were prepared according t o the formula
.
....
17.0 19.5 20.0
Contrary t o Redfern’s statement it was found t h a t “Report of Com. on Methods of Analysis,” J . A . 0. A . C., p. 262.
No. 7
TABLEI1 Lemon, . . . . Lemon. . . . .
Strength Per cent
Oil Found Per cent 10.0 9.5 9.7 10.0 10.0 9.5
For cassia, cinnamon, a n d clove extracts, t h e following modification of t h e official method’ is successful. Dilute I O cc. of the sample with 95 per cent alcohol to 50 cc. as in the case of lemon and orange. Filter. Place I O cc. of the filtrate in a separatory funnel containing 50 cc. water, add I cc. HCl (I : I ) , and shake out 4 times with 2 5 cc. portions of ether. Wash the combined ether extracts twice with water and then shake for a few minutes with about 5 g. granular calcium chloride. Place a small piece of cotton in the outlet of the separatory funnel and draw the ether into a tared beaker. Evaporate the ether on a boiling water bath, place in desiccator for 3 min. and weigh; divide the weight by the specific gravity of the oil to find the per cent of oil by volume. Table I11 gives t h e results on cassia, cinnamon and clove extracts containing I O per cent of t h e respective oils and prepared according t o t h e formula given under lemon and orange. Results on commercial extracts are also given. TABLEI11 Prepared Extracts Found Strength Per cent Per cent Cassia.. . . . . . . . . . 10 9.83 -~ Cassia.. . . . . . . . . . 10 9.90 Cassia., . . . . . . . . . 10 9.94 Cinnamon. . . . . . . . 10 9.90 Cinnamon, . . . . . . . 10 9.96 Cinnamon. . . . . . . . 10 9.90 Clove.. . . . . . . . . . . 10 10.0 Clove. . . . . . . . . . . . 10 9.89 Clove.. . . . . . . . . . . 10 9.95
The results obtained on these extracts are given in Table I. Results obtained on commercial non-alcoholic extracts are alst, given. Commercial Extracts Oil Found Per cent 7.0 17.0 15.0 6.2 14.0 6.5 7.5
IO,
quite accurate results could be obtained b y ordinary steam distillation. It is necessary first t o run blank experiments on pure oils t o determine just what percentage of recovery can be accomplished with t h e particular apparatus a t hand. Using a zoo cc. side-neck distilling flask with outlet tube midway of t h e neck a n d a cassia flask as receiver, t h e writer has consistently recovered g j per cent of lemon a n d orange oils when proceeding as follows: Measure I O cc. of the extract into a graduated cylinder and transfer it by means of about 35 cc. water to a side-neck distilling flask and distil with steam into a I ~ cc. O cassia flask. In the c,ase of lemon and orange oils 95 per cent of the oil is recovered so that the amount found must be multiplied by IOO and divided by g j . Table I1 gives the results obtained b y steam distillation on t h e I O per cent extracts described above.
Essential oil.. . . . . . . . . . . . . . . . 20 cc. Tragacanth.. . . . . . . . . . . . . . . . . 3 g. Glycerin.. . . . . . . . . . . . . . . . . . . 40 CC. Water, q. s . . . . . . . . . . . . . . . . . . .200 CC.
TABLEI Prepared Extracts Oil Found Strength Per cent Per cent 10 Orange, . . . . . . . . . 10 10 Orange, , , . , , . . , 10 9.7 Orange.. . . . . . . . . 10 10 Lemon, . . . . . . . . . 10 10 Lemon, , , , , , , . , . 10 9.5 Lemon. . . . . . . . . . 10 10 Lemon, . . . . . . . . . 10 Lemon. . . . . . . . . . . . .. Lemon. . . . . . . . . . . . .. Lemon. . . . . . . . . . . . .. Lemon. . . . . . . . . . . . ..
Vol.
Commercial Extracts Found Per cent 13.5 12.4
.... ....
17.5
....
....
Almond, anise, and nutmeg extracts of t h e nonalcoholic type are converted into alcoholic extracts as in t h e case of lemon and orange and an aliquot portion analyzed b y t h e official methods.2 P E P P E R M I K T EXTRACT
A standard extract was made u p containing I O per cent peppermint oil by t h e formula given under lemon and orange. I O cc. of this were made u p t o 1 2
“Report of Corn. on Methods of Analysis,” J . A . 0. A . C.,p. 267 I b i d . pp 266 and 269.
July, 1918
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
jo cc. with 9; per cent alcohol, filtered, and a n attempt made t o assay t h e filtrate b y t h e official method’ with t h e following results. These results are calculated t o t h e original extract. I-Following t h e method as given, z per cent of oils found. 2-Heating was carried on for only I min. (shaking a t 1 5 sec. intervals), 8 per cent oil found. 3-Heating was continued for only 45 sec., 8 per cent oil found. 4-Heating was continued for only 2 0 sec., 11 per cent oil found. ;-Heating was continued for 2 j sec., 8 per cent oil found. 6-Heating was continued for 2 0 sec. a n d t h e n t h e suction was continued for an additional I j sec. without heat, 9 per cent oil found. 7-Heating was continued for 2 0 sec. and t h e suction for a n additional I O sec. without heat, 9 per cent oil found. The writer’s experience with this method has been most unsatisfactory, even moderate agreement in duplicate determinations has never been attained. The method leaves too much t o chance. If t h e flask i s not disconnected from t h e suction t h e instant t h e last of the solvent is drawn off, there is B loss of oil, a n d we have not been able t o discover any means whereby we can be assured when this instant is a t hand. Steam distillation gives very good results for peppermint if one determines beforehand what per cent of oil can be recovered with t h e apparatus in blank experiments using known quantities of pure oil. The writer has found this recovery t o be 90 per cent, so t h a t t,he quantity of oil found is multiplied b y roo a n d divided b y 90 t o find t h e amount present i n ‘ t h e extract. Proceeding according t o t h e directions given for lemon a n d orange extracts for steam distillation t h e following results were obtained on a I O per cent nonalcoholic extract a n d on commercial extracts. TABLEIV Prepared Extracts Strength Found Per cent Per cent IO 10 Peppermint. Peppermint. . . . . . . 10 9.8 10 10 Peppermint.
......
.
~-~
......
Commercial Extracts Found Per cent 11.0 12.8
7.2
~
CHEMICALLABORATORIES A N D COMPANY MCCORMICK BALTIMORF,,MARYLAND
-___
A CONTRIBUTION TO THE COMPOSITION O F LIMESULFUR SOLUTIONS2 By 0. B. WINTER
Received April 19, 1918
The principal constituents of lime-sulfur solutions are calcium polysulfides and calcium thiosulfate. Small amounts of calcium sulfate and possibly of calcium sulfite are also present, and t h e claim has been made t h a t t h e solutions may contain other compounds such as hydrogen sulfide, calcium hydrosul1 “Report of Com. on Methods of Analysis,” J . A . 0.A . c., p. 268. 2 This work was done in the chemical laboratory of the Michigan Agricultural College Experiment Station and t h e results are published with the permission of the Director.
539
fide, calcium hydroxyhydrosulfide, different calcium oxysulfides, free lime, a n d free sulfur. How much of each of these compounds is liable t o be present? It is t h e purpose of this paper t o discuss some of the work done in this laboratory which pertains t o t h e above question. HYDROGEN
SULFIDE,
Ca(SH)2.
HzS.
CALCIUM
CALCIUM
HYDROSULFIDE,
HYDROXYHYDROSULFIDE,
CaSHOH I n reviewing t h e literature on t h e composicion of lime-sulfur spray, it is interesting t o note t h e discussions on t h e theoretical composition of t h e solution, together with t h e absence (except in a few articles) of even an attempt t o prove t h e existence of certain of t h e compounds discussed. Divers and Shimidzul give detailed methods for preparing some of t h e abovementioned compounds and s t a t e some of their properties, b u t their work has nothing whatever t o do with a n ordinary lime-sulfur solution. RoarkZ discusses t h e possible existence of these compounds in a limesulfur solution, b u t does not give experimental proof of their presence. T a r t a r a n d Bradley3 conclude t h a t they are not present in appreciable amounts. Thompson and Whittier4 claim t h e presence of hydrosulfide sulfur a n d give experimental d a t a which they believe justifies their claim. Green‘ says, “We have, liowever, never been able t o detect definitely t h e presence of hydrosulfide or free sulfuretted hydrogen in limesulfur solutions.” I t may be possible t o prepare a lime-sulfur solution which contains hydrogen sulfide, calcium hydrosulfide, or calcium hydroxyhydrosulfide, b u t it has yet t o be shown conclusively t h a t any of these compounds are present in appreciable quantities i n a “straight”6 lime-sulfur solution either as a result of t h e preparation of t h e solution, or of hydrolysis or other action taking place during storage under normal conditions. It is also interesting t o note t h a t writers seem t o have different opinions regarding t h e chemical actions which t a k e place in lime-sulfur solutions, and for this reason literature is quite confusing in regard t o t h e formation of a n y of t h e above-mentioned compounds. For example, t h e action of water on a polysulfide is represented as follows b y different chemists: Divers and Shimidzu:7 Cas5 2H20 = Ca(SH)(OH) 3s Ca(SH)(OH) 202 H2S = CaSz03
+
+
+
Auld :8 Cas, zHzO = Ca(0H)Z (x- 1)s H2Sx = HZS Roark : 7 2CaS, z H 2 0 = Ca(SH)2
+
+
+
1 2
3
+ + HzS + 0 4- 2Hz0
+ HzS, + Ca(0H)Z + ~ S , - I
J . Chem. SOC.,411 (1884), 270-91. J . A . 0. A C., [ l ] 1 (1915), 81. THISJ O U ~ N A2L (1910), , 271-7.
Delaware Agricultural College Experiment Station, BUZZ. 105 (1914), 8. Union of S. Africa Dept. of Agr., 3rd and 4th Report of the Director of Vet. Research, 1915, p. 179. 6 By a “straight” lime-sulfur solution is meant a solution prepared from ordinary commercial lime and sulfur t o which no foreign substance has been added, and which has stood for several days 7 LOG. Git. 8 J.’Chem. Sac., [ l ] 107 (1915), 482. 4
5
