: : 11 L be · ;.. I OFI ORNL P 2554 . . . i . . • ! . .. - *. · . L. ". . . .. .. • in : L I.1.25 1.4 .1.6 MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS – 1963 . - - - - - - - - - - - ************** ****** **** . . ...TAR. 6.2004-257** MASTERS Corf-660947-1 MAJICA * NOV 2 9 1968 cownie OF ETHER-UNSATURATE MIXTURES* 1.0.8 1.00; mw_50 NOV 2 9 1966 RELEASED. FOR ANNOUNCEMENT CD, Bopp and W. W. Parkinson Reactor Chemistry Division Oak Ridge National Laboratory Oak Ridge, Tennessee IN NUCLEAR SCIENCE ABSTRACTS The radiation-induced codimerization of athers with un- saturated compounds is being studied since it is believed that useful products may be produced in high yield by this nethod. For example, high yields were obtained by others in the systems cyclic ether-perhalogen olefin and cyclic ether-maleic anhydride, although the nature of the products and the yield proved very : sensitive to the reaction conditions. The experimental procedure in this radiation-synthesis study involved the irradiation of solutions of cyclohexene or dihydrofuran in a saturated furan derivative. In general, the unsaturated constituent made up from 10 to 50% of the solutions. . The starting compounds were purified by refluxing over sodium and fractional distillation using a multiplate. column. .. The ether-unsaturate mixtures were placed in glass tubes, de- gassed by the freeze-thaw evacuation technique, and irradiated by a 6°co source using intensities of 106 to 107 rads/hr. In samples given high dose, space was allowed in the capsule to permit the accumulation of gas without developing excessive pressure. For high temperature irradiations, thick-walled capillary tubes were T *Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation. . mitin 2 . used which were sufficiently strong to withstand the vapor pressure of the mixture. . The codimer and dimer yields were deternined by gas chromatography; the gaseous products were not analyzed. In- itially the yields were estimated by calibration of the chroma- tographic apparatus with dodecane. Several authentic compounds have been prepared and these will be used for a more reliable estimate of quantitative yields. The retention times of the authentic compounds were used as a means for tentative identi- . fication of the radiation products. It is planned to compare the infrared spectra of the radiation products with those of authentic compounds as a further means of identification. . To reduce the analysis time and to improve resolution in chromatography, it was advantageous to use the highest tempera- ture which did not produce decomposition of the sample on the . column. A suitable temperature was chosen by examining the effect of temperature on the ratio of the peak areas of the compound in question to that of a compound known to be stable under the chromatographic conditions. Reacțion on the column was less of a problem with non-polar than with polar columns, but it proved necessary to use both types of columns to increase the certainty of identification of the products, since the order of elution differed between the two column types. With a polar column (Carbowax 20M liquid phase), an ether linkage was found to increase the retention time more than with a non-polar column (silicone rubber liquid phase). . : 1 .. . . . . .. ..... . . .. . . PELY .: :!!i bi . 3 . For the preparation of the authentic compounds which serve as chromatographic standards, the synthetic method generally used was the reaction of an organic magnesium halide (a Grignard reagent) with an organic halide. However, a simpler method was used to prepare dimers: the condensation of halides with active zinc-copper. The halides used in both of these types of reactions were synthesized by well-known methods. For example, 2-chlorotetrahydrofuran was obtained by chlorin- ation of tetrahydrofuran at -50°C; allyl-type bromides (such as 3-bromocyclohexene and 2-bromo-2,5-dihydrofuran) were ob- tained by bromination with a suspension of N-bromosuccimimido in carbon tetrachloride. Special methods which were developed recently by others were used to prepare Grignard reagents from allyl halides and alpha-chloroethers. : The system studied most extensively was cyclohexene in tetrahydrofuran and solutions of these compounds have been irradiated in various concentrations and at several tempera- tures. Chromatographic analysis of the product mixture from a 1:7 cyclohexene-tetrahydrofuran solution showed that the principal products were cyclohexenyl-tetrahydrofuran, octa- hydrodifuryl, tetrahydrodifuryl, and dicyclohexenyl. Approxi- mate yields of these products ranged from G = 0.5 to 2.0 molecules/100 ev.; however these values are being redetermined under more favorable chromatographic conditions. The overall yield of products of low volatility including polymer was LEGAL NOTICE ' 5. This report mo prepared as an account of Goverament sponsored work, Nolther the Vallad sutos, por the Commission, nor any pornog acting on behalf of the Commission: A. Makes any warranty or representation, expressed or inaplied, with respect to the accu- racy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, molhod, or process disclosed in the report may not fairing privately owned righta; or B. Assumes any liabiliues with mngpoct to the use of, or for damages resulting from the use of any information, appenatus, mothod, or proceus discloved in this roport. As used in the above, "person acting on behalf of 1}xe Commiolon" includes any en- ployee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor preparoi, diomminator, or provides access to any information pursuant to be employmeat or coatrac: with the Commission, or his employment with such contractor. 4. HAN G - 18 at 25°C (determined by evaporation in a vacuum). In a 1:3 mixture the same products as in the 1.: 7 mixture were formed and an additional conpound cyclohexyl dihydrofuran was formed in a yield comparable to that of the other products. Irradiation of a 1:3 mixture at 150°C increased the yield of dicyclohexeryl, cyclohexenyl tetrahydrofuran, and octahydro- difuryl about two-fold over the 25°c yield, but cyclohexyl dihydrofuran and tetrahydrodifuryl were not formed in apprecia- ble yield. Irradiation at 300°C (a temperature above the critical point of the mixture) produced about a two-fold increase over the yields at 150°C. Although high yields of codimers were not achieved in the system cyclohexeng-tetrahydrofuran, higher yields are to be expected with systems containing a more reactive unsaturate. . Investigation of the cyclohexene-tetrahydrofuran system is continuing and study of the system dihydrofuran-tetrahydrofuran is commencing. Summary The radiation-induced codimerization of cyclic ethers with unsaturated compounds is being studied. The products were tentatively identified by comparison of their gas chromatographic retention times with those of authentic compounds which were synthesized for this purpose. In order to deterwine the most favorable reaction conditions with cyclohexene-tetrahydrofuran mixtures the effects of composition, temperature, dose rate, and purity were examined. The principal products found by gas chromatography were cyclohexenyl-tetrahydrofuran, cyclohexyl- dihydrofuran, tetrahydrodifuryl, octahydrodifuryl, and dicyclo- hexenyl. The overall yield of products of low volatility including polymer was G - 18 at 25°C (determined by evaporation in vacuum). Although the yields of certain of the products were increased at high temperature, very high yields of codimors (such as were obtained by others in the system cyclic ether- perhalogen olefin) were not achieved. Study of the cyclohexene- tetrahydrofuran system is continuing and study of the system tetrahydrofuran-dihydrofuran is commencing. N " . A END . . . DATE FILMED 3/ 9 / 67 w : . . 1. ST ...10 2 2. . 50 A . LAPOK. Fun F ELESU ..