Bromine atoms, generated by irradiation by a mercury lamp bearing a filter to assure that only wavelengths >310 nm passed, were permitted to react with a series of 1,2-diarylcyclopropanes in carbon tetrachloride solution.The major product in all cases (>80%) was the 1,3-dibromo-1,3-diarylpropane. Kinetic data a t approximately M gave a rate expression dBrddt = -h(cyclopropane)(bromine)'/*. A Hammett treatment of the data gave p = -0.5 for both the cis series and the trans series. Synthesis of several possible minor products and their comparison with the reaction mixture by TLC is reported. Possible reactions such as induced isomerization are thus eliminated from consideration.The addition of halogens to cyclopropanes to give ring opening products is generally accepted as one of the unusual properties af the three-membered ring. In studies of the 1,2-diphenylcyclopropanes and phenylcyclopropane with bromine, LaLonde' delineated three reaction modes: type A, photocatalyzed, nonpolar solvents, free-radical-like ring opening; type B, electrophilic ring opening; and type C, aromatic substitution. This paper addresses itself to type A reactions in the 1,2-diarylcyclopropane series. ResultsIt is important to assure that the reactions which we have studied were the same as those that LaLonde observed. Our work was aimed a t determining something about the reaction's sensitivity to electron density of the cyclopropane ring and, hence, used a number of compounds not used in LaLonde's work. We shall return to examine those that do overlap after considering the general character of our study.We synthesized a series of 1,2-diarylcyclopropanes by standard methods3p4 and characterized them by elemental analysis, molecular weights, and spectral examinations (cf. Table I).Carbon tetrachloride solutions of these compounds were subject to irradiation from a medium-pressure mercury arc (GE-AH-4) equipped with a Corning no. 5031 filter. This filter was effective below 310 nm as seen by the failure of this assembly to expose any malachite green leucocyanide after 1 hr of irradiation.Irradiation of the carbon tetrachloride solutions of the cyclopropanes in the absence of bromine gave no rearrangement or ring opening products after several hours with this system. Mixtures of the cyclopropane solutions with equimolar bromine under dark conditions showed no detectable reaction after 48 hr. For reference, the photo-3005 chemical studies were 90% complete on the order of 120 min.The reaction was shown to utilize 1 mol of bromine per mole of cyclopropane and to produce no HBr, except in the cases of the p-methyl and p-dimethylamino compounds which were not included in the kinetic study as a result.Major products were isolated by chromatography and characterized by spectral means. In two cases, p-chloro and unsubstituted, the 1,3-diaryl-1,3-dibromopropanes were synthesized and the compounds compared with the isolated material and with the TLC and GLC of the reaction mixtures. Several minor product candidates, 1,2-diphenyl-1,3-dibromopropane,...

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A full size mannequin was constructed of fiberglass and plaster, and instrumented with 32 thermocouples, connected to a computer, through a data acquisition system. The mannequin is mounted on a portable platform, and can be moved at a pre-determined speed, to simulate movement of a person fleeing a fire scene.The mannequin was used for a series of nine tests in which the clothing on the mannequin was ignited by a splashed flammable liquid, and the resulting temperatures monitored. In some of the tests the mannequin was equipped, additionally, with an ordinary lab coat.The test results indicate that the mannequin adequately represents the realistic fire insult suffered by the simulated skin of a fire victim. This involves temperatures which can exceed 140°C in less than 1 min.The lab coat was shown to offer a certain degree of fire protection so that the temperatures achieved in its presence were lower than in its absence, by an average of ca. 20°C.

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