OAK RIDGE NATIONAL LABORATORY Operated by UNION CARBIDE NUCLEAR COMPANY Division of Union Carbide Corporation. & Post Office Box X Ridge, Tennessee

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1 X-822 OAK RIDGE NATIONAL LABORATORY Operated by UNION ARBIDE NULEAR OMPANY Division of Union arbide orporation & Oak Post Offie Box X Ridge, Tennessee MA$T fi ORNL ENTRAL FILES NUMBER DATE: SUBJET: TO: FROM: Jvme 8, i960 External Transmittal Authorized The Reation between Sulfuri Aid and Aliphati Hydroarbons, Amso Distribution Willis H. Baldwin OPY NO. ~ ~ Distribution k G. E. Boyd E. H. Taylor F. L. uller R. E. Blano D. E. Ferguson R. H. Rainey Wallae Davis, Jr. K. B. Brown. A. Blake J. M. Shmitt J. R. Flanary M. J. Skinner IT Fred Slilio Engineering Experiment Station Georgia Institute of Tehnology E. M. Kinderman. Stanford Researh Institute L. L. Burger ' Hanford W. B. Lanham Union arbide Olefins ompany. E. Higgins W. H. Baldwin Laboratory Reords - R.. TISE Laboratory Reords entral Researh Lib. Doument Referene Setion NOTIE This doument ontains information of a preliminary nature and was prepared primarily for internal use at the Oak Ridge National Laboratory. It is subjet to revision or orretion and therefore does not represent a final report. The information is not to be abstrated, reprinted or otherwise given publi dissemination without the approval of the ORNL patent branh, Legal and Information ontrol Department.

2 DISLAIMER This report was prepared as an aount of work sponsored by an ageny of the United States Government. Neither the United States Government nor any ageny Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the auray, ompleteness, or usefulness of any information, apparatus, produt, or proess dislosed, or represents that its use would not infringe privately owned rights. Referene herein to any speifi ommerial produt, proess, or servie by trade name, trademark, manufaturer, or otherwise does not neessarily onstitute or imply its endorsement, reommendation, or favoring by the United States Government or any ageny thereof. The views and opinions of authors expressed herein do not neessarily state or reflet those of the United States Government or any ageny thereof.

3 DISLAIMER Portions of this doument may be illegible in eletroni image produts. Images are produed from the best available original doument.

4 LEGAL NOTIE This report was prepared as an aount of Government sponsored work. Neither the United States, nor the ommission, nor any person ating on behalf of the ommission: A. Makes any warranty or representation, expressed or implied, with respet to the auray, ompleteness, or usefulness of the information ontained fn this report, or that the use of any information, apparotus, method, or proess dislosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respet to the use of, or for damages resulting from the use of any information, apparatus, method, or proess dislosed in this report. As used in the above, "person ating on behalf of the ommission" inludes any employee or ontrator of the ommission, or employee of suh ontrator, to the extent that suh employee or ontrator of the ommission, or employee of suh ontrator prepares, disseminates, or provides aess to, any information pursuant to his employment or ontrat with the ommission, or his employment with suh ontrator.

5 -2- Abstrat onentrated sulfuri aid is regularly used to remove unsaturated hydroarbon impurities from saturated aliphati hydroarbons. The reation between onentrated sulfuri aid and saturated aliphati hydroarbons is not so well known. A survey of the hemial literature has been found to inlude studies that show several relatively slow reations. Isotopi exhange with D^SO., raemization of optially ative alkanes, isomerization, leavage to alkanes of lower moleular weight, ombination to ompounds of higher moleular weight and the formation of SOp have been reognized, Amso , the diluent that is used in the solvent extration ativities of the laboratory> reats with sulfuri aid forming sulfur dioxide and low boiling hydroarbon fragments. The overall reation probably results in the formation of more stable hydroarbons by rearrangement. The sulfuri aid treatment an thus produe a more desirable diluent. Introdution Olefins are soluble in 95$ sulfuri aid as the result of a hemial reation. This reation has been and still is used extensively for the removal of olefins from saturated aliphati hydroarbons. Saturated hydroarbons also reat with sulfuri aid at a slower rate and in a different way. The rate of the reation depends upon the struture of the hydroarbon; tertiary hydrogens reat faster than primary or seondary hydrogens. The struture of the remainder of the moleule has a measurable influene on the relative rates of reation of tertiary hydroarbons.

6 -3- Amso , one of the diluents that has been used in solvent extration proesses at the laboratory, ontains several branhed, saturated aliphati hydroarbons (l). It has been stated that the washing of Amso with sulfuri aid has resulted in a diluent that is more desirable for use in proessing (2). Deontamination fators are improved and the physial behavior of the solvent mixture is more favorable after the Amso has been treated with sulfuri aid. It has been demonstrated in our laboratory that sulfuri aid produed more extensive hanges than mere removal of olefins, Long ontating (several days) of Amso with 95$ sulfuri aid resulted in the darkening of the stilfuri aid layer, the formation of S0 and the formation of 9 new hydroarbons that boiled lower than any of the omponents of the starting material. All of the original omponents of the starting Amso were found in the final produt; that is, no ma^or omponent was removed ompletely by the treatment. The relative amounts of the omponents had been altered by the treatment. These observations were based upon qualitative tests of the solvent ("before and after treatment) by gas phase hromatography, Several pertinent observations about these reations were found in the hemial literature* Birh and Dunstan (3) found that 2, 3, k trimethyl pentane was leaved into smaller fragments by sulfuri aid at a faster rate than 2, 2, k trimethyl pentane, 2, 2, 3 trimethyl pentane, 2, 2, 5 trimethyl hexane or 2, 3 dimethyl butane. Whitmore and Johnson (h) stirred 2, 2, k trimethyl pentane with 95$ sulfuri o aid, at 25 for 10 days. Gaseous produts in3.uded sulfur dioxide and hydroarbons. Less than 25$ of the starting hydroarbon was reovered unhanged. More than 35$ of the liquid produt boiled lower and 25$ boiled higher than the starting material. A blak powder was obtained from the aid layer when it was

7 diluted with water. The overall reations inluded sission and ombination of the hydroarbon hains. aesar and Franis (5) heated 2, k dimethyl pentane at 50 with 97$ sulfuri aid and found that 15$ had been isomerlzed to 2, 3 dimethyl pentane. Marshner and armody (6) found 2, 2, k trimethyl pentane to be reative while n pentane and n heptane were but little affeted by sulfuri aid at 2k for 6 hours. Isotopi hydrogen exhange between the hydroarbons and sulfuri aid has been applied to the study of this reation (7,8,9,10,11,12) as well as the use of optially ative hydroarbons (8,9,10). In summary the results of these studies show the following: 1. ompounds with a tertiary hydrogen (,H) show deuterium-hydrogen- ex~ 3 hange at a faster rate than other hydroarbons: n otane exhanged at a rate that was 1$ of the rate found for 2- or 3" methyl heptane (8). 2. Primary hydrogens on methyl groups attahed to the tertiary arbon also exhange with the proton of the sulfuri aid (ll). 3. Oxidative mehanisms are involved in isotopi exhange sine nonoxidizing aids (H PQjJ do not show exhange (7). Sulfur dioxide is a produt of the reation between sulfuri aid and the hydroarbons. k. The rate of raemization of optially ative (+) 3 methyl heptane was found to be 7$ of the rate of isotopi exhange (8). 5. Isomerization was slower than raemization (8). 6. Burwell, et al (.10) have proposed a mehanism that is based on that of Otvos, et al (ll) and Stevenson, et al (12). A hain reation has been proposed that inludes:

8 (a) hain initiation by oxidation (in the following illustrations only the arbon skeletons and essential hydrogens have been used) H + H p SO.- 4 -> + (I) H o 0 + HSO (b) the arbonium ion (i) is the hain arrier that reats by isomerization, H 1 " -> + H () or by intermoleular exhange (the abbreviated ion, II, has been used merely to symbolize a different ation) " 1 + (II) H -> H + + the hain is terminated by the reation of the hain arrier to form an unreative ompound. The reations of arbonium ions that inlude sission and ombination as well as isomerization have been summarized by Whitmore (l3)«the observation (2) that washing of Amso-with sulfuri aid produes a produt that is more desirable in solvent extration proesses an be explained by the isomerization of the hydroarbons under the influene of the sulfuri aid. The ompounds that are most reative toward sulfuri aid are most reative in the solvent extration environment. The effet of the sulfuri aid is to isomerize them to less reative ompounds.

9 -6- Exnerimental Amso (6 ml*) was plaed in a glass stoppered tube with 1.2 ml 95$ sulfuri aid. The mixture was treated at 25 as desribed below. After eah treatment an aliquot (0*5 ml) of the organi phase was removed, washed with water and 10 X portions of the organi phase were examined by gas hromatography to follow the ourse of the reation. The Amso-sulfuri aid mixture was tumbled end over end for one hour. The aid layer had turned yellow but no hange was deteted in the hydroarbon. After an additional 16 hours of tumbling end over end the aid layer was muh darker and low boiling omponents were deteted by gas hromatography. The mixture was allowed to stand without agitation for two weeks. The aid layer was blak; the odor of SOp was deteted but there was no differene from the preeding sample when hromatographed. The mixture was next tumbled end over end for an additional 5 days. The low boiling omponents were now more numerous and were present in larger amounts. The hromatographi analysis has been reprodued in Figure 1. At least 9 new omponents are present. Eo attempt was made to ollet gaseous produts. The gas hromatograph (Perkin-ELner model 154) was operated with a olumn 1 meter long, that had been paked with dinonyl phthalate on mesh elite (0.3 g. ester per g. solid). The olumn was heated at 125.while 50 ml helium per minute was passed through. The results, reprodued in Figure 1, have been seleted to show the Amso before and after treatment with sulfuri aid and known hydroarbons have been inluded for standardization. The hydroarbons shown in Figure 1 appear from the olumn as a funtion of boiling point. There are no speifi interations that lead to speifi separations. Therefore, the known hydroarbons an be used as standards to estimate

10 -7- the boiling points of other omponents. Quantitatively, the weight perentage omposition of the mixtures is nearly proportional to the areas under the urves. In the ase of the Amso, however, the resolution is so poor that the estimation of the omposition beomes quite laborious. It beomes quite evident by a omparison of the Amso before and after treatment that all of the major omponents are still represented. None of the major omponents has been removed ompletely by the sulfuri aid treatment. The original omponents have reated at different rates so that the ratios of the major omponents have been altered. The olefin ontent of Amso is so low as to make the methods of the determination of the olefin quite unreliable. The extent of the deomposition represents hanges in the number of moleules that are many times greater than the apparent olefin ontent.

11 -8- Literature ited 1.. Horton and Baldwin, unpublished data. 2.. A. Blake, private ommuniation. 3. Burh and Dunstan, Trans. Faraday Soiety <3-3, 1013 (1939) 4. Whitmore and Johnson, J. Am. hem. So. 6>3_, 1482 (l94l). 5. aesar and Franis, Ind. Eng. hem. J53_, 1426 (l94l). 6. Marshner and armody, J. Am. hem. So. JJ5, 604 (1951). 7. Setkina, Kursanov, Sterligor and Liberman, hem. Abst. J?0, (1956). 8. Gordon and Burwell, J. Am. hem. So. J_0, 3128 (1948). 9. Gordon and Burwell, J. Am. hem. So. JJL, 2355 (1949). 10. Burwell, Sott, Maury and Hussey, J. Am. hem. So. J_6, 5822 (1954). 11. Otvos, Stevenson, Wagner and Beek, J. Am. hem. So. J, 5741 (1951) 12. Stevenson, Wagner, Beek and Otvos, J. Am. hem. So. Jk, 3269 (1952). 13. Whitmore, hem. Eng. News 26, 668 (1948).

12 -9- Figure 1 Gas-Liquid hromatographi Analysis of Amso Before and After Reation with HpSO^ B A A B D 2, 2, 4 Trimethyl Pentene 2, 2, 5 Trimethyl Hexane n Otane n Deane D Amso Before Treatment Minutes After Air