INDUSTRIAL A N D ENGINEERING CHEMI8TRY
178
Vol. 15, No. 2
Sulfur-Terpene Substitution Compounds’ By William Beach Pratt COMMERCIAL AND SYNTHETICAL LABORATORY, NEWTONVILLE, MASS.
T H E TERM “OIL” in-
This subject, as originalIy designated for discussion in the folAfter several years of dicates substances lowing paper, presents a broad field and one which has been SO work the direction of relittle discussed in the literature that it will be necessary to confine search indicated the use differing widely in this presentation to that class of oils and their surfur compounds of a simple reflux condenser Composition and Properties. We have the fixed Oils, which haoe been the subject of research work and its relation to cornand the ultimate process and product are now patwhich are generally dYcermercial application, as directed by our laboratory. ides of stearic, palmitic, and ented.2 oleic acids; also the essenWe had found that the tial oils, consisting wholly or in part of hydrocarbons or mix- sulfur-terpene product obtained corresponded almost exactly . tures of hydrocarbons with compounds of carbon, hydro- with our ideas of what we were originally working to secure. gen, and oxygen. Broadly, the term is used to include also The especial value was found to be in the treatment of fabric such as are known as mineral oils, which are petroleum hydro- for the manufacture of automobile tires and other rubber carbons, coal-tar hydrocarbons, and various compounds of articles. Being noncolloidal its solutions penetrated the these series. fibers as we had anticipated, so that they became impregIt will only be possible to mention sulfur products of some nated with this product and were so strengthened that of these oils in a general survey of the subject. It is the American peeler cotton thus treated became comparable to large division of the essential oils, known as the terpenes, the more expensive untreated Sea Island or Egyptian cottons. to which our work has been directed and with which we have The solution of the sulfur-terpene compounds is styled had experience in commercial application. “toron,” and the fabric, after impregnation with it, “toronThe particular terpene always associated with sulfur, and treated fabric.” Experience has shown that rubber may be on which one of the largest industries of our country has been calendered to toron-treated fabric with much greater ease established, has a well-recognizedreactionwith sulfur. Never- than to the original gray goods, and that the operation is theless, little is understood as to the real chemistry of vul- attended with a complete absence of the skips or blisters canization in the rubber industry. which occur in ordinary practice with gray goods. This is It is really remarkable in view of the commercial value in due to the fact that the treatment with toron conditions the relation to the combining of sulfur with this terpene, rubber, gray goods so that the surface of the fabric is everywhere that for so many years the other terpenes had not been uniformly prone to adhesion to and incorporation with the investigated in regard to such reaction. rubber. As a consequence “spreading” becomes unnecessary, and thus the time and expense attending this operation are CONNECTION wrm VULCANIZATION eliminated. Moreover, the “friction,” which is the t e r n About twelve years ago the interest of our laboratory was used in the rubber industry to connote the resistance of the . directed to this work through the rapidly increasing demand rubber to separation from the fabric, is markedly greater for for vulcanizing rubber to fabrics. Attempts had been made the toron-treated gray goods than for the same gray goods under pressure, in vacuo, and by every conceivable mechan- untreated. Various other advantages in use, such as proical device, to more perfectly incorporate rubber-benzene tection of the tire fabric from contact with air, moisture, solutions with cotton fabric, in order to give a better bonding and molds, follow such impregnation. But the full effects with rubber compounds. The colloidal structure of the of these are now the subject of searching investigations. rubber and the impossibility of securing a penetration even The fundamental sulfur-terpene compounds themselves between the fibers of the thread, led to this definite problemhave especially engaged the attention of the author, and it is the possibility of constructing a sulfur-terpene compound, the purpose of this paper to present the more important noncolloidal in character, which would be absorbed by the results so far obtained in the investigation of the products cotton fiber, so that when a rubber compound was placed in resulting from the reaction of sulfur and turpentine. contact with the fabric, reaction would occur between the DESCRIPTION OF PRODUCT intimately associated sulfur terpene of the fabric and the rubber mass, thereby effecting a union more permanent in The sulfur-terpene product prepared in the manner derelation to the necessary endurance test of commercial use scribed in the first patent of the series referred to above, and application. from sulfur and American oil of turpentine, which consists There has been little published in the literature concerning largely 6f a-pinene, varies physically from a dark liquid or the combination of sulfur and the liquid terpenes. Because semisolid viscous mass to a black, hard, brittle mass which of our work on the vulcani~ingof rubber, we drew the con- breaks with conchoidal fracture and presents a vitreous clusion that high temperature and high pressure were essen- luster on the surfaces of fracture, and in many respects retial factors to such reaction. I n 1915 we had a bomb consembles the mineral rubbers. The character of the product structed in order to carry out a reaction between sulfur and obtained depends on the proportions of reacting materials, the liquid terpenes at a pressure of 1200 lbs., and carried on the temperature, duration of the process, and other conditions experiments for many months with varying pressures and formation. temperatures. We found that, although little had been pre- of These products are insoluble in water, but are very soluble sented for publication, many of those connected with the in chloroform, carbon disulfide, benzene, toluene, and xylene. technical work of the rubber industry had made similar The “semisolid” products are also almost entirely soluble attempts. in most of the other common organic solvents, but they are 1 Presented before the 15th Annual Meeting of the American Institute of Chemical Engineers, at Richmond, Va , December 6 to 9, 1922.
J
U. 5. Patents 1,348.808 to 1,349,814,inclusive (1920).
TABLE I-PRODUCT WEIGXT G. Fraction 1, up to 155' C. Fraction 2 1 8 0 ' 2 1 4 0 c. Residue
Loss
179
INDUSTR€AL AND ENGINEERING CHEMISTRY
February, 1923
1.8 2.2 20.0 7.0
A
Index of Refraction at lS°C.
S
H
Light yellow liquid, smelled of turpentine mixed with sulfur compound
1.4694
85.55
10.93
3.52
Red liquid, disagreeable odor, faint turpentine odor Hard, brittle mass
1.5587
......
68.61 51.62
8 35 4.60
23 04 43.78
DESCRIPTION
WEIGHT G. 2.0 46.0
DESCRIPTION Similar to Fraction 1 of Product Stiff, viscous mass
Index of COMPOSITION Refraction -PER CENT----at 18O C. C H S 1.4784 84.51 10.68 4.81 55.22 6.57 39.21
A
......
The distillates were condensed in receivers cooled to about 10' C. The temperature of the heating bath of oil was raised slowly to 155' C. At this temperature there was a decided break in the distillation, and the succeeding fraction did not distil until a temperature of 180' c. was reached. The operation was continued up to a maximum of 214' C. The distillation at the higher temperatures was no doubt accompanied by considerable decomposition, as evidenced by the very disagreeable odor of escaping gases or vapors and by the deficiency in weight-of the total fractions.
very difficultly soluble in ethyl and methyl alcohol. The "hard" products are as a rule considerably less soluble than the others. Solutions of these sulfur-terpene compounds pass readily through parchment and according to this test are to be regarded as noncolloidal. This conclusion as to the noncolloidal nature of the sulfur-terpene compounds is confirmed by determinations of the depression of the freezing point of pure benzene by several of these compounds. The sulfur content of the various products varies with the proportions of sulfur and turpentine in the reacting mixture, as well as with the course of the reaction in their formation. Products containing as high as 50 per cent sulfur have been obtained. Analysis of sulfur-terpene compounds prepared from turpentine which contained less than 0.50 per cent of oxygen has demonstrated the absence of oxygen as a constituent of these compounds, and it has been shown further that the passage of air through the sulfur-turpentine mixture during reaction does not result in the introduction of oxygen as a constituent of the final sulfur-terpene product. The reaction between sulfur and turpentine is accompanied by the evolution of hydrogen sulfide, and this fact may be taken as proof that the reaction is in part a t least one of substitution. But the proportions of carbon, hydrogen, and sulfur in the resultant product, as shown by analysis, are not in harmony with an assumption of substitution alone. Rather, the evidence favors strongly also a simple addition of sulfur to the terpene molecule. Moreover, the resdts of determinations of apparent molecular weights by the freeaing-point method seem to require a further assumption of a reaction involving the condensation of two or more molecules of sulfur-terpene compounds. Interesting experiments were made to determine the effect of air agitation during reaction. The results show that the passage of air through the reacting sulfur and turpentine did not affect the introduction of oxygen as a constituent of the final product, but it did apparently cause a reduction in the sulfur content of the product.
DISTILLATION OF
CI'NT---
C
TABLE 11-PRODUCTB Fraction Residue
COXPOSITION ---PER
-
The results are shown in Table I. It thus appears that the sulfur-terpene product A contained about 6 per cent of unattacked turpentine which could be removed by distillation. By making due allowance for the effect of Fraction 1 on the original analysis of Product A, by calculation we obtain the corrected analysis of the sulfur-terpene product A : C, 49.16; H, 5.57; s, 45.27 per cent. If we assume that this substance is a pure, individual compound which is, however, unlikely, and that it contains the same number of carbon atoms as the original terpene from which it was derived, or a multiple of the same, we may write its empirical formula most closely in accord with analysis as C Z ~ H Z ~ S ~ .
PRODUCTB-The maximum temperature of the bath during the distillation of a sample of B (48 9.) was 156" C., and the contents of the distilling flask reached a maximum of 130' C. The pressure varied from 1 1 / 4 to 11/16 in. Only one fraction was removed. There was no evidence of any decomposition during the distillation. From this analysis the empirical formula C20H24SSmay be derived.
COMPOSITION OF A TYPICAL "HARD"SULFUR-TERPENE COMPOUND
This compound was prepared from equal parts by weight of ordinary turpentine and sulfur. The operation was conducted at a comparatively low temperature for approximately 90 hrs., after which time the reaction was completed a t about 170" C. A t the end of the operation, at 170' C., the product was so stiff that it could no longer be stirred, and it showed no tendency to flow. On cooling it became a hard, brittle mass, which for convenience of reference we shall designate as "C." ANALYSIS OF
c
................................ ............................ ...............................
Carbon Hydrogen.. Sulfur.. Oxygen (by difference).
SULFUR-TERPENE PRODUCTS IN PARTIAL VACUUM
THE
.................
Per cent 46.14 4.33 47.80 1.73
PRODUCTA (without air treatment)-A sample (31 g.) of A was
subjected to fractional distillation under a pressure lying between a maximum and minimum of 2a/, and 1 7 / 1 6 in., respectively.
The small proportion of oxygen was very probably derived from the oxygen of the crude turpentine used. Reducing this
TABLE I11
Weight of Sample
COMPOSITION -PER
SUBSTANCB
FORMULA C
BI (before distillation) Ba (after distillation)
C
C~oHzrSa
CEN-
H
S
0
....
56.80
5.82 37.50
55.22
5.57 39.21
....
4 33
1.73
C M H ~ ~ S I 46.14
47.80
0. 0.4604 1.1830 0.4176 0.2300 0.3980 0.2414
Weight of Solvent G. 26.4954 26.8366 20.4902 23.0264 19.2274
20.0012
Undercooling (Mean of 2 Observations) O
c.
0.323 0.613 0.191 0.47 0.125 0.21
Depression F. P.(Mean of 2 . Observa:ions)
C.
0.257 0.635 0.277 0.1315 0.223 0.1345
Depression of
F. P. by
1 G. Sub. in 1000. Solvent
C.
0.1474 0.1430 0.1356 0.1310 0.1075 0.1112
1
Ap arent MoPecular Weight 339 3 349:5 344.4 368.7 381.8 375.3 464.8 449.8 457.3
INDUSTRIAL AND ENGINEERING CHEMISTRY
180
Vol. 15, No.2
analysis to an oxygen-free basis, we have: C, 46.96;H, 4.41;
S,48.63per cent.
This composition corresponds very closely to that of a compound of empirical formula CloHlzS( or CZ~Hz4Ss.
DEPRESSION OF THE FREEZING POINTBY SOLUTIONS OF SULFUR-TERPENE COMPOUNDS These determinations were made in the usual manner for molecular-weight determinations by the freezing-point method, with the Beckmann apparatus, using pure benzene as solvent. The substances examined and the results are shown (Table 111). The results of these determinations show that the depression of the freezing point of benzene by the sulfur-terpene compounds is proportional to concentration ; and, furthermore, the values obtained by calculation of molecular weights from the freezingpoint data are of such magnitude as one should expect in the case of noncolloidal substances. The molecular weight as determined for Ra (375) is somewhat lower thanfhat required for a compound C2oH24Sa (424). This is true also in the case of C, where the determined value is 457 as But only an approximation against 520 required for CzoH&. to agreement was to be expected, as in neither case was the substance supposed to be a single pure compound. However, in both instances, the results indicate condensation of terpene molecules along with the introduction of sulfur.
DISCUSSION
It must be recognized that the reactions between sulfur and turpentine may be and most likely are very complicated, and that the resultant sulfur-terpene products are in consequence very probably mixtures of considerable complexity. For this reason any attempt at the present stage of our investigation to represent by equations and formulas the course of reactions and the constitution of the sulfur-terpene products can be only speculative. If we were dealing here with a pure terpene, the problem would be in large measure simplified. However, since the turpentine employed consists largely of a-pinene, we may assume the reactions in the m*ainto be those between pinene and sulfur, and on this assumption several interesting possibilities are at once suggested. We may consider one such possibility. As previously stated, the results of our experiments show ’not only substitution and simple addition in the terpene molecule, but also some kind of condensation of molecules. Assuming the Baeyer picean-ring representation of the constitution of a-pinene,a we should expect the addition of one atom of sulfur at the position of the double CH bond. The possibility of the addition of a second sulfur atom is suggested cHa by the ready intramolecular reC arrangement of the pinene molecule CH so commonly observed, wherein dipentene, containing two double bonds, is derived from pinene.4
“:3
The addition of the second atom of sulfur may be represented as accompanied by molecular rearrangement as follows:
CH
CA
The formation of a compound of the composition C2&& from the above CldH16s2 by substitution of sulfur might then be represented in the following manner: CH.
CHS
Some such explanation as this may be applicable to the formation and structure of the sulfur-terpene product A, described above, and having the composition represented by the empirical formula C~oH27S7,and with such modifications as may be required in each case, to the other products. THE ACTIONOF SULFURON ORGANIC COMPOUNDS. SOMETYPICAL EXAMPLES One of the oldest examples of the action of sulfur on organic substances is the well-known method of preparing hydrogen sulfide by the fusion of paraffin with sulfur, which appears to involve the formation of more condensed hydrocarbon molecules from which hydrogen has been partially removed in combination with sulfur.6 And in the field of the dyese
Assuming, therefore, the addition of two atoms of sulfur to one molecule of pinene, we may express this action in two stages : 8 4
Bey., as (1896),2779. Wallach, “Terpene und Campher,” 1914, 16,
5 Clarke, “Data of Geochemistry,” U.S. Geol Survey, Bull. 830 (1908). 627, footnote. 6 Lange, “Die Schwefelfarbstoffe, ihre Herstellung and Verwendung;” Nietzki, “Chemie der Organischen Farbstoffe;” Cain and Thrope, “The Synthetic Dyestuffs, etc.;” Wahl and Atack, “The Manufacture of Organic Dyestuffs.”
February, 1923
INDUSTRIAL AND ENGINEERING CHEMISTRY
we have that large class of substances known as the sulfur dyes, many of which are the result of the direct action of sulfur. The reactions involved in the formation of these dyes are doubtless in most cases quite complex, but in numerous instances they are well established as consisting essentially in the addition or substitution of sulfur, usually accompanied by the evolution of hydrogen sulfide, and the conjugation of two or more molecules through sulfur. F’urthermore, the role of sulfur in the formation of natural and artificial asphalts’ is very generally recognized as an important one and as involving the condensation and polymerization of organic materials to form products which may or may not contain sulfur as a constituent. For instance, according to Winklers artificial coal-tar asphalt can be greatly improved by heating with about 5 per cent of sulfur until the evolution of hydrogen sulfide ceases, whereby a molecular condensation takes place, with removal of hydrogen and the formation of a more difficultly fusible residue. Very similar products are the well-known wood cement of Hauslerg prepared from coal tar, pitch and sulfur, and the sulfur-tar or benzasphalt!,lO made by boiling two parts of sulfur in three parts of coal tar. Many other such examples of the action of sulfur on organic compounds are to be found in the literature, and we give below a bibliography which we believe is representative of the literature regarding those compounds whose reaction with elementary sulfur has been investigated.
BIBLIOGRAPHY Turpentine:
Lange, “Die Schwefelfarbstoffe,” 14; Winkler, Chem.
Zentr., 29 (18581,337. Ethylene: Meyer and Sandmeyer, Ber., 16 (1883),2176. Acetylene: Meyer and Sandmeyer, LOC. cit.; de Coninck, Bull. sca’. acad. roy. Belg., 1908, 303; C. A , , 8 (1909), 643; Capelle, BUZZ. SOC. chim., [4]8 (1908),150; C . A . , 2 (leos),1562. Styrene: Baumann and Fromm, Ber., 88 (1895),890. Stilbene: Baumann and Klett, Ibid., 24 (1891), 3310; cf. Ann., 38
(1841), 320. Benzene: Renard, Bull. SOC. chim., [3] 6 (1891), 194; Merz and Weith, Ber., 4 (1871),394. Toluene: Renard, Bull. SOG. chim., [3]4 (1890), 958; Ibid., 5 (1S91), 278; Lange, “Die Schwefelfarbstoffe,” 24. Dibenzyl: Szperl and Wierusz-Kowalski, Chem. Zentr., 89 (1918),908; abstract of Chem. Polski, 15 (1917),19. Haphthalene: Merz and Weith, Zilricher Chem. Harmonika; Bey., 2 (l869),341 (see Lange, “Die Schwefelfarbstoffe”). Anthracene: Badische Anilin und Soda Fabrik, D. R. P. 186,990. Indene, hydrindene, and cyclopentadiene: Friedmann, Ber., 49 (1916), 50; C. A . , 10 (1916), 896; Ber., 49 (1916), 683; C. A., 10 (19161,2712. Aniline: Merz and Weith, Zilvicher Chem. Harmonika; Ber., 2 (1869), 341 (see Lange, “Die Schwefelfarbstoffe”); Kraft, Bet‘., 7 (1874),385,1164; Kehrmann and Bauer, Ibid., 89 (1896),2363; Hofmann, Ibid., 27 (1894),
2806, 3320. +Toluidine: Merz and Weith, Ber., 4 (1871), 393; D.R. P. 34,299; Truhlar, Ber., 20 (1887), 664; Dah1 and others, D. R. P., 35,790;Jacobson, Ber., 22 (1889), 333; Gattermann, Ibid., 28 (1889), 424; 26 (1892), 1084; cf. Anschiitz and Schultz, Ibid., 22 (1889), 581; Green, Ibid., 22
(1889), 969. nt-Tolylenediamine: Cassella and Co., D. R. P. 139,430 and D. R.P. 152,595;Schultz and Beyschlag, Ber., 42 (1909),743;C. A., 8 (1909), 1176. Diphenylanime: Bernthsen, A n n , , 280 (1885),77. Benzanilide (phenylbenzamide): Hofmann, Ber., 12 (18791, 2360; 18 (1880),1223; Lange, “Die Schwefelfarbstoffe,” 18.
Tetramethyldiaminodiphenylmethane: Nietzki, Chem. d. org. Farbs. Cinnamic Acid: Baumann and Fromm, Bet‘., 88 (1895),891. Benzyl alcohol, diphenylcarbinol, dibenzyl ether, and diphenylcarbinol ether: Szperl and Wierusz-Kowalski, Chem. Zentr., 89 (1918),909,abstract o f Chem. Polski, 15 (1917),23. Phenol: Mdhlaus and Seyde, Chem.-Ztg., 81 (19071,987. Kohler, “Die Chemie und Technologie der Niiturlichen and Kiinstlichen Asphalte,” 1918. a Chem. Zentr., !3? (1858),337. 8 See Nljthling, Der Asphalte,” 192. 10 Wagner’s Jahrcsber., 1860, 554.
181
A Rapid Method for the Deterrnination of Salt in Oleomargarine and Butter’ By Fred F. Flanders CHSMICAL
LABORATORY, MAS9ACHUSETTS DEPARTMENT OF MENTAL DISEASES.BOSTON,MASS.
The following method for the determination of salt in oleomargarine and butter has been used in making hundreds of determinations and has been proved to be rapid and accurate. A 3-g. sample is weighed out on a torsion balance sensitive to 10 mg. For this purpose a small, narrow copper funnel has been found most useful. Its dimensions are 2 in. long, tapering from 3/4 in. a t the large end to a/a in. a t the small end. It is easily made by cutting a sector out of No. 22 gage sheet copper with tin shears. If the edges are smoothed with a file the piece is easily rolled into a neat funnel. When weighing, it is supported on a tripod made by twisting up No. 18 copper wire. After weighing the sample, the funnel and tripod are transferred to the neck of a 300-cc. Erlenmeyer flask. The top of the funnel, which projects about, one-third of its height above the mouth of the flask, is gently warmed with a small Bunsen flame. The fat melts and rune into the flask. The funnel is then rinsed down with 15 cc. of chloroform in such a way as to remove the film of fat, and the flask is gently rotated until solution is complete. The funnel is then washed down by playing a stream of hot water upon it from a wash bottle. Not more than 50 cc. of water should be used. Five or six drops of 10 per cent potassium chromate indicator are added and the salt titration conducted by running in 0.1 N silver nitrate solution. The flask should be rotated constantly during the titration. Duplicate determinations should check within 0.1 cc., and 0.1 cc. should be deducted for the end-point. A complete determination, including weighing, may be made in 5 or 6 min. A blank should be run on the chloroform, using 50 cc. of water and 5 drops of chromate indicator. Occasionally, old samples of chloroform develop phosgene and hydrochloric acid, so that if more than 0.1 cc. of silver nitrate solution is required to give a strong end-point, the chloroform should be shaken in a separatory funnel with dilute sodium hydroxide and Gltered through a dry, folded filter. 1 Received January
22,1923.
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